Film for optical elements

A film for optical elements is formed by a liquid crystalline composition comprising the following components (a) and (b): PA1 (a) a liquid crystalline polymer which exhibits an optically positive uniaxial property; and PA1 (b) a polycyclic compound having a molecular weight of not more than 1,000 and wherein a plurality of alicyclic rings and/or aromatic rings are connected together through a linkage chain of 0 to 4 main-chain carbon atoms bonded to different ring carbon atoms, with hydrocarbon groups each having 1 to 20 carbon atoms being bonded respectively to both end rings through a linkage chain of 0 to 4 main-chain carbon atoms, PA2 an orientation form formed in the state of liquid crystal of said liquid crystalline composition being fixed.

FIELD OF THE INVENTION
 The present invention relates to a film for optical elements in which the
 orientation of a composition containing a liquid crystalline polymer
 exhibiting a uniaxial property is fixed. More particularly, the invention
 is concerned with a viewing angle improving film and a twisted nematic
 liquid crystal display device having the said film.
 BACKGROUND OF THE INVENTION
 An active drive twisted nematic type liquid crystal display device
 (hereinafter referred to simply as "TN-LCD") using TFT element or MIM
 element affords an image quality comparable to a CRT as seen from the
 front side, in addition to the characteristics inherent in LCD such as
 small thickness, light weight and low power consumption. For this reason,
 the TN-LCD is spread widely as a display for notebook type personal
 computers, portable telephone and portable information terminals. However,
 the conventional TN-LCD inevitably involves a problem associated with a
 viewing angle such that there occurs change in display color or a lowering
 of display contrast when seen obliquely, due to refractive index
 anisotropy. It has keenly been desired to solve this problem, and various
 attempts have been made for improvement. For example, there have been
 proposed a method (halftone gray scale method) wherein one pixel is
 divided and the voltage applied to each divided pixel is changed at a
 certain ratio, a method (domain dividing method) wherein one pixel is
 divided and a rising direction of liquid crystal molecules in each divided
 pixel is changed, a method (IPS method) wherein a lateral electric field
 is applied to liquid crystal, a method (VA liquid crystal method) wherein
 a vertically oriented liquid crystal is driven, and a method (OCB method)
 wherein a bend orientation cell and an optical compensator are combined
 together. Developments and trial manufacture have been made in connection
 with these proposed methods.
 Although these methods afford certain effects, it is necessary that
 alignment layer, electrodes and liquid crystal orientation be changed from
 those so far adopted.
 For this change it is required to establish appropriate manufacturing
 techniques and new manufacturing equipment, with consequent difficulty of
 manufacture and increase of cost.
 On the other hand, a method has been proposed wherein the viewing angle is
 enlarged by incorporating an optical compensating film in the conventional
 TN-LCD without changing at all the structure of TN-LCD itself. This method
 is simple and very economical because it is not necessary to make reform
 or increase of the TN-LCD manufacturing equipment. For this reason, this
 method is now attracting attention of many concerns.
 In manufacturing the said film, the following are mentioned as examples of
 conditions required of the film material:
 1) Should a high reliability worthy of commercialization in point of
 resistance to heat, moisture and light.
 2) Should be capable of being oriented under wide conditions and should
 afford products having little irregularity and few orientation defects.
 3) Should have a high film strength and a sufficient impact resistance and
 be superior in handleability.
 However, in the case of forming a film with use of a known film material,
 it has been difficult for the film to fully satisfy all of the above
 conditions. Under the circumstances, it has been considered necessary to
 develop a material which satisfies the above conditions without
 deteriorating the optical performance of the film.
 OBJECTS OF THE INVENTION
 It is an object of the present invention to solve the above-mentioned
 problems and particularly provide a film for optical elements which film
 is of a good quality, superior in reliability and strength and having few
 defects and little irregularity.
 SUMMARY OF THE INVENTION
 The present invention, in the first aspect thereof, resides in a film for
 optical elements, formed by a liquid crystalline composition comprising
 the following components. (a) and (b):
 (a) a liquid crystalline polymer which exhibits an optically positive
 uniaxial property; and
 (b) a polycyclic compound having a molecular weight of not more than 1,000
 and wherein a plurality of alicyclic rings and/or aromatic rings are
 connected together through a linkage chain of 0 to 4 main-chain carbon
 atoms bonded to different ring carbon atoms, with hydrocarbon groups each
 having 1 to 20 carbon atoms being bonded respectively to both end rings
 through a linkage chain of 0 to 4 main-chain carbon atoms,
 an orientation form formed in the state of liquid. crystal of the said
 liquid crystalline composition being fixed.
 The present invention, in the second aspect thereof, resides in the above
 film for optical elements, wherein the orientation form is a nematic
 hybrid orientation form.

DETAILED DESCRIPTION OF THE INVENTION
 The present invention will be described in more detail hereinunder.
 The film for optical elements according to the present invention is
 applicable to various optical elements by adjusting the orientation form
 of the liquid crystalline polymer which determines optical characteristics
 of the film. For example, the film of the invention is employable suitably
 as optically functional films typical of which are a viewing angle
 improving film, a color compensating film, and a polarizing film.
 Particularly, the film with a nematic hybrid orientation fixed is suitable
 as a viewing angle improving film for TN-LCD and it can greatly improve
 the viewing angle dependence of TN-LCD.
 A description will now be given of TN-LCD to be subjected to compensation.
 TN-LCDs can be classified by driving methods into a simple matrix type and
 an active matrix type using an active element such as electrode, i.e., TFT
 (Thin Film Transistor) electrode or MIM (Metal Insulator Metal) or TFD
 (Thin Film Diode) electrode. For any of the driving methods the viewing
 angle improving film of the present invention exhibits an outstanding
 viewing angle improving effect.
 The known halftone gray scale method (pixel dividing method) and domain
 dividing method have been developed in an effort to widen the viewing
 angle of LCD from the driving liquid crystal cell side. Even for such LCDs
 somewhat improved in viewing angle, the viewing angle improving film of
 the present invention is effective and can make a further improvement for
 the viewing angle.
 It is desirable that the film in question have a fixed nematic hybrid
 orientation. The nematic hybrid orientation indicates an orientation form
 wherein the liquid crystalline polymer is nematic-oriented and the angle
 of director in the liquid crystalline polymer relative to the film upper
 surface and the angle of director in the liquid crystalline polymer
 relative to the film lower surface are different from each other. Thus,
 since the director-film surface angle is different between the vicinity of
 the upper interface and the vicinity of the lower interface, it can be
 said that the said angle changes continuously between the upper and lower
 surfaces of the film.
 In the viewing angle improving film of the present invention having the
 nematic hybrid orientation form, the directors of the liquid crystalline
 polymer face at different angles at all positions in the film thickness
 direction. Thus, when the film is observed as a structure, there no longer
 is any optical axis.
 The film in question can be obtained by using a liquid crystalline
 composition comprising (a) a liquid crystalline polymer which exhibits an
 optically positive uniaxial property and (b) a specific compound which
 will be described later.
 As examples of the liquid crystalline polymer are mentioned condensed type
 liquid crystalline polymers obtained by condensing compounds having
 carboxyl, alcohol, phenol, amino, or thiol group, liquid crystalline vinyl
 polymers starting from liquid crystalline compounds having a double bond
 such as acryloyl, methacryloyl, vinyl, or allyl group, liquid crystalline
 polysiloxanes prepared from liquid crystalline compounds having
 alkoxysilane group, liquid crystalline epoxy resins prepared from liquid
 crystalline compounds having epoxy group, and mixtures of these liquid
 crystalline polymers. Above all, condensed type liquid crystalline
 polymers are most preferred in view of optical characteristics of the
 resulting film.
 Usually, a condensed type liquid crystalline polymer can be prepared by
 condensing a bifunctional monomer in a suitable manner. As the
 bifunctional monomer, an aromatic or cyclohexane ring-containing
 bifunctional monomer is preferred. Examples are diamines such as
 phenylenediamine, diols such as hydroquinone, 2-methylhydroquinone,
 resorcinol, catechol, 4-methylcatechol, 4-tert-butylcatechol, and
 2,3-dihydroxynaphthalene, dithiols such as 1,4-phenylenedithiol and
 1,2-phenylenedithiol, hydroxycarboxylic acids such as salicylic acid,
 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 3-hydroxy-2-naphthoic acid,
 6-hydroxy-2-naphthoic acid, and 7-hydroxy-2-naphthoic acid, amino acids
 such as 2-aminobenzoic acid, 3-aminobenzoic acid, and 4-aminobenzoic acid,
 and dicarboxylic acids such as phthalic acid, isophthalic acid,
 terephthalic acid, 1,4-naphthalenedicarboxylic acid,
 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid,
 4,4'-biphenyldicarboxylic acid, 4,4'-stilbenedicarboxylic acid, and
 1,4-cyclohexanedicarboxylic acid. Particularly, condensed type liquid
 crystalline polymers containing a catechol unit as a hydroxyl-containing
 component and as an essential structural unit are most preferred.
 Also employable are condensed type liquid crystalline polymers obtained by
 adding any of the following compounds into the starting monomer to such an
 extent as will not destroy the liquid crystallinity: aliphatic
 dicarboxylic acids such as oxalic acid, fumaric acid, succinic acid,
 glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and
 sebacic acid, aliphatic diols such as ethylene glycol, propylene glycol,
 butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol,
 and decanediol, aliphatic diamines such as diaminoethane, diaminopropane,
 diaminobutane, diaminopentane, diaminohexane, diaminoheptane,
 diaminooctane, diaminononane, and diaminodecane, aliphatic
 hydroxycarboxylic acids such as hydroxyacetic acid, hydroxypropionic acid,
 hydroxybutyric acid, hydroxyvaleric acid, hydroxyhexanoic acid,
 hydroxyheptanoic acid, hydroxyoctanoic acid, hydroxynonanoic acid, and
 hydroxydecanoic acid.
 If necessary, a monofunctional monomer may be added into the starting
 monomer for modifying main-chain ends of the liquid crystalline polymer
 used. As examples of the monofunctional monomer are mentioned monomers
 containing one carboxyl, amine, alcohol, phenol, or thiol group in each
 molecule.
 Aromatic and aliphatic carboxylic acids are mentioned as examples of
 carboxyl-containing monofunctional monomers.
 As preferred examples of aromatic carboxylic acids are mentioned benzoic
 acids substituted in the 2-, 3-, or 4-position with a C.sub.1-20 alkyl or
 alkoxy group such as methoxybenzoic acid, ethoxybenzoic acid,
 propoxybenzoic acid, butoxybenzoic acid, pentoxybenzoic acid,
 hexyloxybenzoic acid, heptyloxybenzoic acid, octyloxybenzoic acid,
 nonyloxybenzoic acid, decyloxybenzoic acid, toluic acid, ethylbenzoic
 acid, propylbenzoic acid, butylbenzoic acid, pentylbenzoic acid,
 hexylbenzoic acid, heptylbenzoic acid, octylbenzoic acid, nonylbenzoic
 acid, and decylbenzoic acid.
 As examples of aliphatic carboxylic acids are aliphatic mentioned
 carboxylic acids having 2 to 20 carbon atoms such as acetic acid,
 propionic acid, butyric acid, pentanoic acid, hexanoic acid, heptanoic
 acid, octanoic acid, nonanoic acid, and decanoic acid.
 Particularly preferred among the above monofunctional monomers are those
 substituted in the 4-position such as 4-methoxybenzoic acid,
 4-ethoxybenzoic acid, 4-propoxybenzoic acid, 4-butoxybenzoic acid,
 4-pentoxybenzoic acid, 4-hexyloxybenzoic acid, 4-heptyloxybenzoic acid,
 4-octyloxybenzoic acid, 4-nonyloxybenzoic acid, and 4-decyloxybenzoic
 acid.
 As examples of monofunctional monomers having an amine group are mentioned
 aromatic and aliphatic amines.
 Examples of aromatic amines are anilines substituted in the 2-, 3-, or
 4-position with a C.sub.1-20 alkyl or alkoxy group, and examples of
 aliphatic amines are aliphatic amines having 2 to 20 carbon atoms.
 Where required, the monofunctional monomers exemplified above may contain
 an optically active group. Examples are benzoic acid derivatives derived
 by partial substitution of aromatic rings with an optically active group,
 and optically active aliphatic acids. Particularly preferred are benzoic
 acid compounds with aromatic ring partially substituted by an optically
 active group, such as 4-methylpropoxybenzoic acid,
 4-(2-methylbutoxy)benzoic acid, 4-methylbutoxybenzoic acid,
 4-methylpentyloxybenzoic acid, 4-methylhexyloxybenzoic acid,
 4-methylheptyloxybenzoic acid, 4-menthyloxybenzoic acid,
 4-isomethyloxybenzoic acid, and 4-bornyloxybenzoic acid.
 As examples of monofunctional monomers having a alcohol or phenol group are
 mentioned phenols and aliphatic alcohols. Examples of phenols include
 those substituted in the 2-, 3-, or 4-position with a C.sub.120 alkyl,
 alkoxyl, or alkoxycarbonyloxy group. Examples aliphatic alcohols include
 those having 2 to 20 carbon atoms. As more concrete examples of such
 phenols and aliphatic alcohols are mentioned cresol, ethylphenol,
 nonylphenol, butanol, pentanol, hexanol, and cyclohexanol, with cresol and
 nonylphenol being preferred.
 The alkyl, alkoxy and aliphatic groups referred to above may contain an
 unsaturated bond or may contain an optically active group.
 If necessary, there also may be used monomers having three or more
 functional groups such as trimellitic acid, dihydroxybenzoic acid,
 hydroxybenzenedicarboxylic acid, benzenetricarboxylic acid, and
 pyromellitic acid, as well as optically active monomers such as
 1-methylethanediol, 1-ethylethanediol, 1-methylpropanediol,
 1-methylbutanediol, 2-methylbutanediol, 1-methylpentanediol,
 2-methylpentanediol, cyclopentanediol, cyclohexanediol, 2-methylsuccinic
 acid, and 3-methyladipic acid.
 No special limitation is placed on how to condense the above monomers to
 prepare condensed type liquid crystalline polymers, more particularly,
 liquid crystalline polyesters. Any method known in this field may be
 adopted. For example, there may be adopted a method involving activating a
 carboxylic acid by making the carboxylic acid into an acid halide or using
 a dicyclohexylcarbodiimide and subsequent reaction with alcohol or amine,
 a method involving subjecting phenol to an acetic-esterification and
 subsequent reaction with a carboxylic acid, allowing a deacetylation
 reaction to take place, or a method involving esterifying a carboxylic
 acid into an ester such as methyl ester, subsequent reaction with alcohol
 in the presence of a suitable solvent if necessary, and a dealcoholation
 reaction.
 Two or more kinds of such condensed type liquid crystalline polymers
 exemplified above may be used as a mixture, or any of them may be mixed
 with a non-liquid crystalline polymer or a liquid crystalline vinyl
 polymer, polysiloxane or epoxy resin insofar as the effect of the present
 invention is not impaired thereby.
 It is desirable that the liquid crystalline polymer used in the invention
 possess a tilt-orientability or a homeotropic-orientability in the state
 of liquid crystal. The tilt-orientability means a property capable of
 assuming a state such that when the liquid crystalline polymer is
 heat-treated on a suitable substrate with an upper side opposite to the
 substrate being made an air or vacuum side, an acute angle of director in
 the liquid crystalline polymer to a film surface in the vicinity of the
 air- or vacuum-side interface is larger than that in the vicinity of the
 substrate. On the other hand, the homeotropic-orientability means a
 property such that in the same case as above, the directors of the liquid
 crystalline polymer can assume a state of orientation nearly perpendicular
 to the substrate surface.
 Whether the liquid crystalline polymer possesses a tilt-orientability or a
 homeotropic-orientability is determined by forming a layer of the liquid
 crystalline polymer on a substrate and judging the state of its
 orientation. The substrate employable in this judgment is not specially
 limited, but as examples there are mentioned glass substrates such as soda
 glass, potash glass, borosilicate glass, and optical glasses, e.g. crown
 glass and flint glass, as well as films and sheets of plastic materials
 which are heat-resistant in a temperature region in which the liquid
 crystalline polymer assumes a state of liquid crystal, such as
 polyethylene terephthalates, polyethylene naphthalates, polyphenylene
 oxides, polyimides, polyamide-imides, polyether imides, polyamides,
 polyether ketones, polyether ether ketones, polyketone sulfides, and
 polyether sulfones.
 The substrate exemplified above is used after cleaning its surface with an
 acid, alcohol, or detergent. It is desirable that the aforesaid judgment
 of orientability be made on a substrate not having been subjected to any
 surface treatment such as silicone treatment, rubbing, or uniaxial
 stretching. But in the judgment of tilt-orientability there also may be
 used a substrate having been subjected to rubbing or uniaxial stretching.
 It is desirable that the liquid crystalline polymer exhibiting a positive
 uniaxial property and used in the invention form a 0.1.about.1,000 .mu.m
 thick film thereof on any of the substrates exemplified above and that
 when heat-treated at a temperature at which the liquid crystalline polymer
 presents a liquid crystal state, the polymer exhibits a tilt orientation
 or a homeotropic orientation on at least any one of the exemplified
 substrates. Certain liquid crystalline polymers exhibit a peculiar
 homeotropic orientation at temperatures near the liquid crystal-isotropic
 phase transition point. Usually, therefore, it is preferable that the
 above heat treatment be conducted at a temperature 15.degree. C.,
 preferably 20.degree. C., lower than the liquid crystal-isotropic phase
 transition point. In this case, if the liquid crystalline polymer exhibits
 a tilt orientation, it is possible to see a state (a state of opposite
 tilt directions as will be described later) in which a discrimination line
 is observed despite the quenching axes of adjacent domains being the same.
 If the polymer exhibits a homeotropic orientation, it is possible to make
 sure the orientation with use of a conoscope or the like.
 The molecular weight of the liquid crystalline polymer used in the present
 invention is usually in the range of 0.01 to 1.0, preferably 0.03 to 0.5,
 more preferably 0.05 to 0.3, in terms of an inherent viscosity as
 determined in any of various solvents, say, a mixed
 phenol/tetrachloroethane (60/40 weight ratio) solvent, at 30.degree. C. If
 the inherent viscosity is lower than 0.01, the mechanical strength of the
 resulting film may be deteriorated or the reliability thereof against high
 temperature and high humidity may be impaired. If the inherent viscosity
 is higher than 1.0, there is a fear that the orientation may be impaired
 or the viscosity in the formation of liquid crystal may become too high,
 with consequent increase of the time required for orientation.
 The present invention provides a liquid crystalline composition obtained by
 adding to the above liquid crystalline polymer (a) which exhibits an
 optically positive uniaxial property a polycyclic compound (b) having a
 molecular weight of not more than 1,000 and wherein a plurality of
 alicyclic rings and/or aromatic rings are connected together through a
 linkage chain of 0 to 4 main-chain carbon atoms bonded to different ring
 carbon atoms, with hydrocarbon groups each having 1 to 20 carbon atoms
 being bonded respectively to both end rings through a linkage chain of 0
 to 4 main-chain carbon atoms.
 The polycyclic compound (b) used in the present invention, which has the
 above chemical structural characteristic, can be represented by the
 following general formula (1):
EQU R.sup.1 --(B.sup.1 --A.sup.1)--(B.sup.2 --A.sup.2)-- . . . --(B.sup.n
 --A.sup.n)--B.sup.n+1 --R.sup.2 (1)
 where R.sup.1 and R.sup.2 are each independently a hydrocarbon group having
 1 to 20 carbon atoms, A.sup.1 to A.sup.n are each a ring structure bonded
 through different constituent atoms to two adjacent B.sup.n s, B.sup.1 to
 B.sup.n+1 are each a single bond or an organic group of 1 to 4 atoms
 interposed between any of adjacent R.sup.1, R.sup.2, and A.sup.n, and n is
 an integer of 2 to 8.
 The A.sup.1 to A.sup.n are each a ring structure bonded through different
 constituent atoms to two adjacent B.sup.n s. It is preferable that the
 ring structures include at least one six-membered ring. The ring
 structures as referred to herein are represented as aliphatic rings and/or
 aromatic rings. As examples thereof, mention may be made of benzene group,
 indene group, polycyclic aromatic groups such as naphthalene, anthracene,
 phenanthrene, triphenylene, pyrene, and perylene, heteroaromatic groups
 such as pyridine, pyrimidine, pirazine, pyridazine, and triazole, and
 polycyclic aromatic groups containing a hetero-atom such as isoquinoline
 and quinoline. The ring structures may be such that the aromatic groups
 exemplified above are connected together through a plurality of
 non-aromatic ring structures, examples of which include fluorene,
 acenaphthylene, dibenzofuran, carbazole, xanthene, phenoxazine, phenazine,
 and dibenzodioxin groups. Unsaturated bonds in the ring structures may be
 hydrogenated partially or wholly, examples of which include cyclohexane,
 cyclohexene, tetrahydroxynaphthalene, decahydroxynaphthalene, and
 acenaphthene groups. Where required, the ring structures may each contain
 one or more substituent groups. As examples of such substituent groups are
 mentioned C.sub.1-10 hydrocarbon groups, as well as alkoxy, phenoxy,
 trifluoromethyl, hydroxyl, amino, and nitro groups, and halogen atoms. If
 plural substituent groups are present, they may be the same or different.
 In the general formula (1), B.sup.1 to B.sup.n+1 are each a single bond or
 an organic group of 1 to 4 atoms interposed between any of adjacent
 R.sup.1, R.sup.2, and A.sup.n, provided the intervening atoms do not
 constitute a part of the ring structures. As examples of such organic
 groups are mentioned:
 --O--, --NR.sub.1 --, --(C.dbd.O)--, --O--(C.dbd.O)--,
 --NR--(C.dbd.O)--, --CR.sub.1.dbd.CR.sub.1 --, --C.ident.C--,
 --CR.sub.2 --CR.sub.1.dbd.CR.sub.1 --CR.sub.2 --, --CR.sub.2 --, --CR.sub.2
 --C.ident.C--CR.sub.2 --,
 --O--(C.dbd.O)--C.ident.C--, --(S.dbd.O)--,
 --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --O--CR.sub.1.dbd.CR.sub.1 --O--,
 --O--(C.dbd.O)--C.dbd.C--,
 --(CR.sub.2).sub.n --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.2)
 --(CR.sub.2).sub.n --O--CH.sub.2 -- (n=1, 2),
 --O--(CR ).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --NR--(CR.sub.2).sub.n --(n=1.about.3),
 --N.dbd.CH--(CR.sub.2).sub.n --(n=0.about.2),
 --(CR.sub.2).sub.n --O--(CO)--(n=1.about.2),
 where R.sub.1 and R.sub.2 are each a hydrogen atom or a hydrocarbon group
 having 1 to 10 carbon atoms, provided R.sub.1 s need not be the same, and
 if there are n number of R.sub.2 s, the R.sub.2 s may be mutually
 different.
 The following organic groups are particularly preferred:
 --O--, --(C.dbd.O)--, --O--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 --CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1
 --,
 --O--(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --, --(CR.sub.2).sub.n
 --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2).sub.n --O--(CO)--(n=1.about.2),
 In the general formula (1), R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms. Examples are
 straight-chain, saturated hydrocarbon groups such as methyl, ethyl,
 propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl,
 dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl,
 octadecyl, nonadecyl, and eicosyl; branched, secondary or tertiary,
 saturated hydrocarbon groups such as methylethyl, 1-methylpropyl,
 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl,
 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl,
 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl,
 1-methylheptyl, 2-methylheptyl, 3-methylheptyl, 4-methylheptyl,
 5-methylheptyl, 6-methylheptyl, 1-methyloctyl, 1-methylnonyl,
 3,7-dimethyloctyl, 3,5,5-trimethylhexyl, and dimethylethyl; unsaturated
 hydrocarbon groups such as allyl, butenyl, pentenyl, and hexenyl; and
 hydrocarbon groups having a cyclic structure such as cyclopentyl,
 cyclohexyl, cyclohexenyl, cyclohexylmethyl, cyclohexylethyl,
 cyclohexylpropyl, phenyl, benzyl, phenethyl, naphthyl, naphthylmethyl,
 menthyl, norbornyl, bornyl, and isomenthyl.
 More concrete structural formulas of the foregoing general formula (1) will
 be described below:
 Structural Formula 1
 ##STR1##
 In the structural formula 1, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.10 are
 each independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1 is a single bond or at least one organic group
 selected from group A, X.sub.2 and X.sub.3 are each a single bond or an
 organic group selected from --O-- and --O--(C.dbd.O)--, provided in the
 organic groups of X.sub.1, X.sub.2 and X.sub.3 there also is included a
 structural formula with valences being reversed right and left.
 &lt;Group A&gt;
 --O--, --(C.dbd.O)--, --O--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 --CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1
 --,
 --O--(C.dbd.O),
 --(CR.sub.2).sub.n --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2)n (n=1.about.2),
 --(CR.sub.2).sub.n --O--(C.dbd.O)--(n=1.about.2),
 where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided Rs need not be the
 same, and if there are n number of R.sub.2 s, the R.sub.2 s may be
 mutually different.
 Structural Formula 2
 ##STR2##
 In the structural formula 2, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.14 are
 each independently a hydrogen atom, F, Cl, R, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1 and X.sub.2 are each independently a single bond
 or at least one organic group selected from group A, and X.sub.3 and
 X.sub.4 are each independently a single bond or an organic group selected
 from --O-- and --O--(C.dbd.O), provided in the organic groups of X.sub.1,
 X.sub.2, X.sub.3 and X.sub.4 there also is included a structure with
 valences being reversed right and left.
 &lt;Group A&gt;
 --O--, --(C.dbd.O)--, --O--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 --CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1
 --,
 --O--(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --(CR.sub.2).sub.n --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2).sub.n --O--(C.dbd.O)--(n=1.about.2)
 Where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided R.sub.1 need not
 be the same, and if there are n number of R.sub.2, the R.sub.2 s may be
 different from each other.
 Structural Formula 3
 ##STR3##
 In the structural formula 3, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.18 are
 each independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1 and X.sub.2 are each independently a single bond
 or at least one organic group selected from group A, and X.sub.3 and
 X.sub.4 are each independently a single bond or an organic group selected
 from --O-- and --O--(C.dbd.O)--, provided in the organic groups of
 X.sub.1, X.sub.2, X.sub.3 and X.sub.4 there also is included a structural
 formula with valences being reversed right and left:
 --CR.sub.1 --CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1 --CR.sub.1 --,
 --O--(C.dbd.O).sub.n --CR.sub.1.dbd.CR.sub.1 --,
 --(CR.sub.2).sub.n --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2).sub.n --(C.dbd.O)--(n=1.about.2)
 where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided R.sup.1 s need not
 be the same, and if there are n number of R.sub.2 s, the R.sub.2 s may be
 mutually different.
 Structural Formula 4
 ##STR4##
 In the structural formula 4, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.14 are
 each independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1 and X.sub.2 are each independently a single bond
 or at least one organic group selected from group A, X.sub.3 and X.sub.4
 are each independently a single bond or an organic group selected from
 --O-- and --O--(C.dbd.O)--, provided in the organic groups of X.sub.1,
 X.sub.2, X.sub.3 and X.sub.4 there also is included a structural formula
 with valences being reversed right and left.
 &lt;Group A&gt;
 --O--, --(C.dbd.O)--, --O--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 --CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1
 --,
 --O--(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --(CR.sub.2).sub.n --(n=1.about.4)
 --O--(CR.sub.2).sub.n --O--(n=1.about.4)
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2).sub.n --O--(C.dbd.O)--(n=1.about.2),
 where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided R.sub.1 s need not
 be the same, and if there are n number of R.sub.2 s, the. R.sub.2 s may be
 mutually different.
 Structural Formula 5
 ##STR5##
 In the structural formula 5, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.14 are
 each independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1 and X.sub.2 are each independently a single bond
 or at least one organic group selected from group A, and X.sub.3 and
 X.sub.4 are each independently a single bond or an organic group selected
 from --O-- and --O--(C.dbd.O)--, provided in the organic groups of
 X.sub.1, X.sub.2, X.sub.3 and X.sub.4 there also is included a structural
 formula with valences being reversed right and left.
 &lt;Group A&gt;
 --O--, --(C.dbd.O)--, --O--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --O--(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --(CR.sub.2).sub.n --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2).sub.n --O--(C.dbd.O)--(n=1.about.2),
 where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided R.sub.1 s need not
 be the same, and if there are n number of R.sub.2 s, the R.sub.2 s may be
 mutually different.
 Structural Formula 6
 ##STR6##
 In the structural formula 6, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.18 are
 each independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1 and X.sub.2 are each independently a single bond
 or at least one organic group selected from group A, and X.sub.3 and
 X.sub.4 are each independently a single bond or an organic group selected
 from --O-- and --O--(C.dbd.O), provided in the organic groups of X.sub.1,
 X.sub.2, X.sub.3 and X.sub.4 there also is included a structural formula
 with valences being reversed right and left.
 &lt;Group A&gt;--O--, --(C.dbd.O)--, --O--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 --CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1
 --,
 --O--(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --(CR.sub.2).sub.n --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2)--O--(C.dbd.O)--(n=1.about.2),
 where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided R.sub.1 s need not
 be the same, and if there are n number of R.sub.2, the R.sub.2 s may be
 mutually different.
 Structural Formula 7
 ##STR7##
 In the structural formula 7, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.18 are
 each independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1, X.sub.2 and X.sub.3 are each independently a
 single bond or at least one organic group selected from group A, and
 X.sub.4 and X.sub.5 are each independently a single bond or an organic
 group selected from --O-- and --O--(C.dbd.O)--, provided in the organic
 groups of X.sub.1, X.sub.2, X.sub.3, X.sub.4 and X.sub.5 there also is
 included a structural formula with valences being reversed right and left.
 &lt;Group A&gt;
 --O--(C.dbd.O)--, --0--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 --CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1,
 --O--(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --(CR.sub.2).sub.n --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2).sub.n --O--(C.dbd.O)--(n=1.about.2),
 where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided R.sup.1 s need not
 be the same, and if there are n number of R.sub.2 s, the R.sub.2 s may be
 mutually different.
 Structural Formula 8
 ##STR8##
 In the structural formula 6, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sub.22 are
 each independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1, X.sub.2, X.sub.3, and X.sub.4 are each
 independently a single bond or at least one organic group selected from
 group A, and X.sub.5 and X.sub.6 are each independently a single bond or
 an organic group selected from --O-- and --O--(C.dbd.O), provided in the
 organic groups of X.sub.1, X.sub.2, X.sub.3, X.sub.4, X.sub.5 and X.sub.6
 there also is included a structural formula with valences being reversed
 right and left.
 &lt;Group A&gt;
 --O--, --(C.dbd.O)--, --O--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 --CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1
 --,
 --O--(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --(CR.sub.2).sub.n --(n=1.about.4),
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2).sub.n --O--(C.dbd.O) (n=1.about.2),
 where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided R.sup.1 s need not
 be the same, and if there are n number of R.sub.2 s, the R.sub.2 s may be
 mutually different.
 Structural Formula 9
 ##STR9##
 In the structural formula 9, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sub.3 to R.sup.6 are each
 independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group or
 alkoxy group, X.sub.1 and X.sub.2 are each independently a single bond or
 an organic group selected from --O-- and --O--(C.dbd.O)--, provided in the
 organic groups of X.sub.1 and X.sub.2 there also is included a structural
 formula with valences being reversed right and left.
 Structural Formula 10
 ##STR10##
 In the structural formula 10, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.6 are each
 independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group or
 alkoxy group, and X.sub.1 and X.sub.2 are each independently a single bond
 or an organic group selected from --O-- and --O--(C.dbd.O)--, provided in
 the organic groups of X.sub.1 and X.sub.2 there also is included a
 structural formula with valences being reversed right and left.
 Structural Formula 11
 ##STR11##
 In the structural formula 11, R.sup.1 and R.sup.2 are each independently a
 hydrocarbon group having 1 to 20 carbon atoms, R.sup.3 to R.sup.10 are
 each independently a hydrogen atom, F, Cl, Br, C.sub.1-6 hydrocarbon group
 or alkoxy group, X.sub.1 and X.sub.2 are each independently a single bond
 or at least one organic group selected from group A, and X.sub.3 and
 X.sub.4 are each independently a single bond or an organic group selected
 from --O-- and --O--(C.dbd.O), provided in the organic groups of X.sub.1,
 X.sub.2, X.sub.3 and X.sub.4 there also is included a structural formula
 with valences being reversed right and left.
 &lt;Group A&gt;
 --O--, --(C.dbd.O)--, --O--(C.dbd.O)--, --NR.sub.1 --(C.dbd.O)--,
 --CR.sub.1.dbd.CR.sub.1 --, --NR.sub.1 --(C.dbd.O)--CR.sub.1.dbd.CR.sub.1
 --,
 --O--(C.dbd.O)--CR.sub.1.dbd.CR.sub.1 --,
 --(CR.sub.2).sub.n --(n=1.about.4)
 --O--(CR.sub.2).sub.n --O--(n=1.about.4),
 --(CR.sub.2).sub.n --O--CH.sub.2 --(n=1, 2),
 --O--(CR.sub.2).sub.n --(n=1.about.3),
 --O--(C.dbd.O)--(CR.sub.2).sub.n --(n=1.about.2),
 --(CR.sub.2).sub.n --O--(C.dbd.O)--(n=1.about.2),
 where R.sub.1 and R.sub.2 are each independently a hydrogen atom or a
 hydrocarbon group having 1 to 10 carbon atoms, provided R.sub.1 s need not
 be the same, and there are n number of R.sub.2 s, the R.sub.2 s may be
 mutually different.
 Regarding how to prepare the compounds of the above structures, there is no
 special limitation. There may be adopted any method known in the field
 concerned. The compounds in question need not be pure compounds. For
 example, they may be used without removing impurities by produced during
 synthesis insofar as there is no obstacle to formation or use of the film
 of the invention such as deterioration of orientability or colorization .
 Further, plural such compounds may be used as a mixture.
 Any of the compounds represented by the general formula (1) is used in an
 amount of 0.1 to 20 wt %, preferably 0.3 to 10 wt %, relative to the
 liquid crystalline polymer described previously. If its amount is smaller
 than 0.1 wt %, it may be impossible to obtain a uniform orientation, while
 if it is larger than 20 wt %, a bad influence may result in a reliability
 test such as a heat resistance test.
 In the present invention, a liquid crystalline composition comprising the
 liquid crystalline polymer exhibiting an optically positive uniaxial
 property and the compound of the general formula (1) is oriented
 preferably in a nematic hybrid orientation form uniformly on an orienting
 substrate and in the state of liquid crystal, which orientation is then
 fixed, to prepare a film for optical elements. To this end, it is
 desirable to use the following orienting substrate and go through the
 following steps.
 Generally, for obtaining a nematic hybrid orientation with use of a liquid
 crystalline composition, it is desirable that a layer of the said liquid
 crystalline composition be sandwiched vertically in between different
 interfaces. In this case, if the upper and lower interfaces are the same,
 the same orientation will result at the upper and lower interfaces, thus
 making it difficult to obtain a nematic hybrid orientation.
 According to a concrete method for forming the film of the invention, a
 single orienting substrate and an air interface are utilized, and lower
 and upper interfaces of a layer of the liquid crystalline composition are
 brought into contact with an orienting substrate and air, respectively. It
 is also possible to use upper and lower orienting substrates of different
 interfaces, but from the standpoint of a manufacturing process it is
 desirable to use one orienting substrate and an air interface.
 It is preferable for orienting substrates employable in the invention to
 possess anisotropy so that they can define a tilt direction of the liquid
 crystal molecules (the projection of directors to the orienting
 substrate). If the orienting substrates cannot define a tilt direction of
 liquid crystal at all, there will be obtained only such an orientation
 form as tilts in disorderly directions (disorderly vectors as director
 projections to the substrate).
 As examples of orienting substrates employable in the present invention
 there are mentioned film substrates and uniaxially stretched film
 substrates both formed using such plastic materials as polyimides,
 polyamide-imides, polyamides, polyether imides, polyether ether ketones,
 polyether ketones, polyketone sulfides, polyether sulfones, polysulfones,
 polyphenylene sulfides, polyphenylene oxides, polyethylene terephthalates,
 polybutylene terephthalates, polyethylene naphthalates, polyacetals,
 polycarbonates, polyacrylates, acrylic resins, polyvinyl alcohols,
 polypropylenes, cellulosic plastics, epoxy resins, and phenolic resins, as
 well as metallic substrates such as aluminum, iron and copper substrates
 having slits in the surfaces thereof, and glass substrates such as alkali
 glass, borosilicate glass and flint glass substrates having slit-like
 etched surfaces.
 In the present invention there may be used rubbed plastic film substrates
 obtained by rubbing the above plastic film substrates, as well as rubbed
 thin plastic films such as rubbed polyimide films and rubbed polyvinyl
 alcohol films. Further, the substrates exemplified above may have
 obliquely vapor-deposited films of silicon oxide.
 Among the various orienting substrates exemplified above, preferred
 examples for forming the nematic hybrid orientation of the liquid
 crystalline composition are substrates each having a rubbed polyimide
 film, rubbed polyimide substrates, rubber polyether ether ketone
 substrates, rubbed polyether ketone substrates, rubbed polyether sulfone
 substrates, rubbed polyphenylene sulfide substrates, rubbed polyethylene
 terephthalate substrates, rubbed polyethylene naphthalate substrates,
 rubbed polyarylate substrates, and cellulosic plastic substrates.
 In the case where the liquid crystalline composition in the film of the
 present invention forms a nematic hybrid orientation, the angle of
 director in the liquid crystalline composition to a film surface is
 different between the upper and lower surfaces of the film. At the
 substrate-side film surface the said angle can be adjusted to an angle in
 either the range of 0.degree. to 200 or the range of 30.degree. to
 90.degree. by suitably selecting an orienting method or the kind of the
 liquid crystalline composition to be used. From the standpoint of a
 manufacturing process it is usually desirable to adjust the director-film
 surface angle in the vicinity of the film interface contacting the
 orienting substrate to an angle in the range of 0.degree. to 20.degree..
 In this case, the director-film surface angle in the vicinity of the film
 interface not in contact with the orienting substrate is adjusted to an
 angle in the range of 30.degree. to 90.degree..
 The film of the invention is obtained by applying the liquid crystalline
 composition uniformly onto the orienting substrate described above and
 then going through a uniformly orienting step and an orientation fixing
 step. The application of the liquid crystalline composition onto the
 orienting substrate can be done in a state of solution of the liquid
 crystalline composition dissolved in any of various solvents or in a
 melted state thereof. The former, solution coating, is preferred in the
 manufacturing process.
 For the solution coating, first the liquid crystalline composition is
 dissolved in a solvent to prepare a solution having a predetermined
 concentration. The film thickness (the thickness of a layer formed by the
 liquid crystalline composition) is decided at the stage of applying the
 liquid crystalline composition onto the substrate and therefore it is
 necessary to control the concentration of the solution and the film
 thickness accurately.
 What solvent is to be used cannot be said sweepingly because it depends on
 the kind (say composition ratio) of the liquid crystalline composition
 used, but examples of solvents employable include halogenated hydrocarbons
 such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane,
 tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene,
 and orthodichlorobenzene, phenols such as phenol and parachlorophenol,
 aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene,
 and 1,2-dimethoxybenzene, as well as acetone, ethyl acetate, tert-butyl
 alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol
 monomethyl ether, diethylene glycol dimethyl ether, ethyl cellosolve,
 butyl cellosolve, 2-pyrrolidone, N-methyl-2-pyrrolidone, pyridine,
 triethylamine, tetrahydrofuran, dimethylformamide, dimethylacetamide,
 dimethyl sulfoxide, acetonitrile, butyronitrile, carbon disulfide, and
 mixtures thereof such as mixed solvents of halogenated hydrocarbons and
 phenols.
 The concentration of the solution used depends on the solubility of the
 liquid crystalline composition used and the thickness of the film to be
 obtained, but is usually in the range of 3 to 50 wt %, preferably 5 to 30
 wt %.
 In the case of using a solvent having a high surface tension, a surface
 active agent may be added into the solution if necessary for performing
 the application of the solution stably. Any surface active agent may be
 used insofar as it can lower the surface tension of the solution and
 stabilize the film formed. But fluorine-based surfactants are particularly
 preferred. Suitable surfactants available commercially are employable such
 as Fluorad, (a product of 3M Co.), Paintadd (Dow Corning Co.), SURFLON
 (Asahi Glass Co.), Unidyne (Daikin Kogyo Co.), MEGAFAC (Dainippon Ink
 Co.), F-TOP (Shin Akita Kasei Co.), SOTERJET (NEOS Co.), ARON-G (Toa Gosei
 Co.), and Modiper (Nippon Oils & Fats Co.). No limitation is made to these
 surfactants, but it goes without saying that products of other companies
 having equal chemical structures are also employable.
 The amount of the surfactant used is usually in the range of 0.001 to 1 g
 based on 1 kg of the solution. A larger amount than 1 g may result in the
 surfactant becoming a foreign matter in the liquid crystalline composition
 and causing a defect of the composition. There also is a fear that a
 longer time may be required for the formation of orientation or the
 orientation form of liquid crystal may be badly influenced, such as
 impairment of orientation.
 After adjustment to a desired concentration with use of the solvent, the
 solution of the liquid crystalline composition is applied onto the
 orienting substrate described above. In this case there may be adopted a
 suitable coating method such as spin coating, roll coating, die coating,
 printing, dipping/pulling-up, or curtain coating.
 After the coating the solvent is removed, allowing a layer of the liquid
 crystalline composition having a uniform thickness to be formed on the
 orienting substrate. How to remove the solvent is not specially limited.
 Any method may be adopted insofar as the solvent can mostly be removed and
 the layer of the liquid crystalline composition does not flow or drop.
 Usually the solvent is removed by drying at room temperature, drying in a
 drying oven, or by spraying of warm or hot air.
 This coating and drying stage intends to form a uniform layer of the liquid
 crystalline composition on the substrate, with a liquid crystal
 orientation of the composition being not formed yet. A liquid crystal
 orientation of monodomain, preferably a nematic hybrid orientation, is
 completed by a heat treatment which follows.
 In forming a nematic hybrid orientation by heat treatment, the lower the
 viscosity of the liquid crystalline composition, the better, for promoting
 the orientation induced by an interfacial effect. Therefore, the higher
 the heat treatment temperature, the more desirable. In certain liquid
 crystalline compositions, an average tilt angle, which will be described
 later, may differ depending on the heat treatment temperature. In this
 case, it is necessary to set a heat treatment temperature suitable for
 obtaining a desired average tilt angle. For example, when there occurs the
 necessity of performing the heat treatment at a relatively low temperature
 for obtaining an orientation of a certain tilt angle, the low temperature
 keeps the liquid crystalline composition high in viscosity, resulting in
 that the time required for orientation becomes longer. In such a case, it
 is effective to adopt a method wherein heat treatment is once conducted at
 a high temperature to afford a monodomain orientation and thereafter the
 heat treatment temperature is dropped to a desired level stepwise or
 gradually. Anyhow, it is desirable to perform the heat treatment at a
 temperature above the glass transition point of the liquid crystalline
 composition used in accordance with characteristics of the composition,
 more particularly, of the liquid crystalline polymer. In the case where
 two or more liquid crystalline polymers are used, it is desirable to set a
 suitable heat treatment temperature in accordance with the glass
 transition points of the polymers. More specifically, it is desirable that
 the heat treatment be carried out at a temperature higher than the glass
 transition point of the polymer which is the highest in the same point
 among the two or more liquid crystalline polymers.
 The heat treatment temperature necessary for the formation of a liquid
 crystal orientation is usually in the range of 50.degree. to 300.degree.
 preferably 70.degree. to 280.degree. C., more preferably 100.degree. to
 260.degree. C. As noted previously, there also may be adopted a continuous
 heat treatment involving plural temperatures, namely, a continuous heat
 treatment comprising a heat treatment at a certain temperature and
 subsequent heat treatment at a lower or higher temperature.
 The heat treatment time necessary for the liquid crystalline composition to
 exhibit a satisfactory orientation on the orienting substrate depends on
 the kind (say, composition ratio) of the liquid crystalline composition
 used and the heat treatment temperature adopted, but is usually in the
 range of 10 seconds to 120 minutes, preferably 30 seconds to 60 minutes.
 If the heat treatment time shorter than 10 seconds, there is a fear that
 the orientation obtained may be unsatisfactory. Also, a longer time than
 120 minutes is not desirable because the productivity may be deteriorated.
 In this way, in the state of liquid crystal, it is possible to obtain a
 nematic hybrid orientation which is uniform throughout the whole surface
 of the orienting substrate.
 A magnetic or electric field may be utilized in the above heat treatment.
 However, if a too strong magnetic or electric field is applied during heat
 treatment, a uniform field force will be exerted on the liquid crystalline
 composition during application of the field, so that the directors of the
 liquid crystal are apt to face in a certain direction. In other words, it
 becomes difficult to obtain such a nematic hybrid orientation as in the
 present invention wherein the directors define different angles at
 different positions in the film thickness direction.
 The nematic hybrid orientation thus formed in the state of liquid crystal
 of the liquid crystalline composition can be fixed, without impairing the
 uniformity of the orientation, by cooling to a temperature below the
 liquid crystal transition point of the composition. Generally, in the case
 of using a liquid crystalline composition which has a smectic phase or a
 crystal phase in a lower temperature region than the nematic phase, the
 nematic orientation in the state of liquid crystal may be destroyed by
 cooling. The liquid crystalline composition used in the present invention
 possesses the following properties:
 1 Does not have any smectic phase or crystal phase below the nematic phase
 temperature region.
 2 Even if the liquid crystalline composition has a smectic or crystal phase
 latently, the smectic or crystal phase does not appear at the time of
 cooling.
 3 In the working temperature range of the film for optical elements, the
 liquid crystalline composition does not exhibit fluidity nor any change in
 its orientation form even with an external field or force applied thereto.
 Thus, there will not occur the destruction of the orientation form caused
 by a phase transition to the smectic phase or crystal phase, and a liquid
 crystal orientation, preferably a nematic hybrid orientation, of a
 completely monodomain can be fixed.
 The foregoing cooling temperature is not specially limited if only it is
 below the liquid crystal transition point of the liquid crystalline
 composition used. For example, by cooling at a temperature 10.degree. C.
 lower than the liquid crystal transition point, it is possible to fix a
 uniform liquid crystal orientation. Means for cooling is not specially
 limited. The orientation formed can be fixed by merely transferring the
 liquid crystalline composition from within the heating atmosphere in the
 heat treatment step into an atmosphere held at a temperature below the
 liquid crystal transition point of the composition, for example, into a
 room temperature atmosphere. For enhancing the production efficiency there
 may be adopted a forced cooling such as air or water cooling, or removal
 of heat. In certain liquid crystalline compositions, however, the average
 tilt angle obtained somewhat differs, depending on the cooling rate. When
 such a liquid crystalline composition is used and when there occurs the
 necessity of controlling the average tilt angle strictly, it is desirable
 that appropriate cooling conditions be established in carrying out the
 cooling operation.
 The following description is now provided about controlling the angle in
 the film thickness direction of the nematic hybrid orientation. When the
 nematic hybrid orientation is fixed in the film of the invention, the
 absolute value of the composition director-film surface angle in the
 vicinity of the upper or lower interface of the film is in the range of
 one to 20.degree. at one of the upper and lower surfaces of the film and
 is in the range of 30.degree. to 90.degree. at the opposite surface.
 Control can be made to a desired angle by selecting a suitable kind (say,
 composition ratio) of a liquid crystalline composition to be used. a
 suitable orienting substrate and suitable conditions for heat treatment.
 Even after fixing the nematic hybrid orientation, control can be made to a
 desired angle by adopting a suitable method such as a method of scraping
 the film surface uniformly or a method of dipping the film in a solvent to
 melt the film surface uniformly. In this case, it is necessary to select a
 suitable solvent according to the kind (say, composition ratio) of the
 liquid crystalline composition used and that of the orienting substrate
 used.
 In the film of the invention obtained through the above steps, a uniform
 nematic hybrid orientation is fixed. Since the said orientation is formed,
 the upper and lower portions of the film are not equivalent to each other
 and anisotropy is found also in the intra-film surface direction. Thus,
 the film can be utilized as a viewing angle improving film for a liquid
 crystal display (LCD), and by disposing the film in an LCD it is possible
 to derive various characteristics.
 A more detailed description will be given below about a method of using the
 film of the invention as a viewing angle improving film.
 In the case of disposing a viewing angle improving film in a twisted
 nematic type liquid crystal cell, the film can be used in any of the
 following modes of use:
 1 The orienting substrate is peeled from the film and the film is used
 alone as a viewing angle improving film.
 2 The film formed on the orienting substrate is used as it is.
 2 The film as a viewing angle improving film is laminated onto another
 substrate different from the orienting substrate and is used.
 In the case of using the viewing angle improving film alone, the film alone
 can be obtained by, for example, any of a method in which the orienting
 substrate is peeled off at the interface with the viewing angle improving
 film mechanically using a roll or the like, a method in which the film and
 the orienting substrate are dipped in a solvent which is a poor solvent
 for all of the constituent materials and thereafter the orienting
 substrate is peeled off mechanically, a method in which the orienting
 substrate is peeled off by the application of ultrasonic wave thereto, a
 method in which a temperature change is induced by utilizing the
 difference in thermal expansion coefficient between the orienting
 substrate and the film, and a method in which the orienting substrate
 itself or an alignment layer thereon is dissolved off. Since releasability
 differs depending on the kind of the liquid crystalline composition used
 and the adhesion thereof to the orienting substrate, there should be
 adopted a method most suitable for the system concerned. In the case of
 using the viewing angle improving film alone, a certain film thickness
 does not afford a self-supporting property of the film. In such a case,
 for ensuring the strength and reliability of the film, it is desirable
 that the film be fixed through an adhesive or a pressure-sensitive
 adhesive onto a substrate which is preferred in point of optical
 properties, such as a plastic substrate, examples of which are
 polymethacrylates, polycarbonates, polyvinyl alcohols, polyether sulfones,
 polysulfones, polyacrylates, polyimides, amorphous polyolefins, and
 triacetyl cellulose.
 A description will now be given of the case where the viewing angle
 improving film is used as it is formed on the orienting substrate. If the
 orienting substrate is optically isotropic or if it is required for a
 TN-LCD (twisted nematic liquid crystal display), the film on the substrate
 can be incorporated into the TN-LCD as it is as a desired compensating
 element.
 A description will now be given of the case where the viewing angle
 improving film of the invention obtained by fixing the orientation of the
 liquid crystalline composition on the orienting substrate is peeled from
 the substrate and is then laminated onto another substrate more suitable
 for optical use. In this case, the viewing angle improving film of the
 invention can be incorporated into a TN-LCD as a compensating laminate
 constituted at least by the film and the another substrate different from
 the orienting substrate. For example, when the orienting substrate used
 exerts an undesirable influence on a TN-LCD although it is necessary for
 obtaining a nematic hybrid orientation, the said substrate can be removed
 from the viewing angle improving film after fixing the orientation. More
 specifically, it is possible to adopt te following method.
 A substrate ("the second substrate" hereinafter) suitable for a liquid
 crystal display to be installed into a TN-LCD and the viewing angle
 improving film on the orienting substrate are affixed together using, for
 example, an adhesive or a pressure-sensitive adhesive. Then, the orienting
 substrate is peeled off at the interface with the viewing angle improving
 film, allowing the film to be transferred onto the second substrate side
 suitable for the liquid crystal display, to afford a compensating element.
 As to the second substrate to be used for the transfer, no special
 limitation is placed thereon if only it has a moderate flatness, but glass
 substrates and transparent plastic films having an optical isotropy are
 preferred. As examples of such plastic films are mentioned films of
 polymethyl methacrylates, polystyrenes, polycarbonates, polyester
 sulfones, polyphenylene sulfides. polyacrylates, amorphous polyolefins,
 triacetyl cellulose, and epoxy resins. Above all, polymethyl
 methacrylates, polycarbonates, polyacrylates, polyether sulfones, and
 triacetyl cellulose are preferred. Even optically anisotropic films are
 employable if they are required for the TN-LCD concerned. As examples of
 optically anisotropic films are mentioned retardation films obtained by
 stretching plastic films such as polycarbonate and polystyrene films, as
 well as polarizing films.
 As an example of the second substrate there is mentioned a liquid crystal
 cell itself. The liquid crystal cell uses two upper and lower glass or
 plastic substrates with electrodes. If the viewing angle improving film of
 the present invention is transferred onto one or both of the upper and
 lower glass or plastic substrates, it follows that the incorporation of
 the film has been completed. Of course, the viewing angle improving film
 of the present invention can also be fabricated using as an orienting
 substrate a glass or plastic substrate itself which is a constituent of
 the liquid crystal cell.
 It is not necessary for the second substrate to substantially have an
 orientation controlling ability for the liquid crystalline composition,
 nor is it necessary to form an alignment layer or the like between the
 second substrate and the film.
 As to the adhesive or pressure-sensitive adhesive for affixing the second
 substrate used for the transfer and the viewing angle improving film of
 the invention to each other, there is no special limitation if only it is
 of an optical grade. For example, there may be used any of acrylic,
 epoxy-, ethylene/vinyl acetate copolymer-, rubber- and urethane-based
 adhesives and pressure-sensitive adhesives, as well as mixtures thereof.
 As the adhesive there may be used any of thermosetting, photo-setting, and
 electron beam-curable type adhesives insofar as they are optically
 isotropic.
 The transfer of the viewing angle improving film of the present invention
 onto the second substrate suitable for a liquid crystal display can be
 accomplished by peeling off the orienting substrate at the interface with
 the film after the bonding. As examples of peeling methods, though
 referred to previously, there are mentioned a mechanical peeling method
 using a roll or the like, a method involving dipping in a solvent which is
 a poor solvent for all of the constituent materials and a subsequent
 mechanical removal of the orienting substrate, a peeling method using
 ultrasonic wave in a poor solvent, a peeling method using a temperature
 change based on the difference between the orienting substrate and the
 film, and a method of dissolving off the orienting substrate itself or the
 alignment layer thereon. There should be adopted a method most suitable
 for the system concerned because releasability differs depending on the
 kind of the liquid crystalline composition used and the adhesion thereof
 to the orienting substrate.
 The viewing angle improving film of the invention may be coated with a
 protective layer such as a transparent plastic film for the purpose of
 protecting the surface, enhancing the strength and improving the
 environmental reliability.
 The viewing angle improving film thus obtained exhibits an excellent
 viewing angle compensating effect for TN-LCDs. The thickness of the film
 required to exhibit a more suitable compensating effect for various
 TN-LCDs cannot be said sweepingly because it depend on the type of the
 TN-LCD concerned and various optical parameters. But it is usually in the
 range of 0.1 to 20 .mu.m, preferably 0.2 to 10 .mu.m, more preferably 0.3
 to 5 .mu.m. If the film thickness is smaller than 0.1 .mu.m, a
 satisfactory compensating effect may not be obtained, and if it exceeds 20
 .mu.m, the display may be colorized unnecessarily.
 However, for deriving the performance of the viewing angle improving film
 to a higher extent, it is desirable that a more detailed consideration be
 given to optical parameters and axial configuration of the film.
 A more detailed description will be given below.
 Reference will be made first to an intra-film surface apparent retardation
 value obtained when the viewing angle improving film is seen in the normal
 line direction thereof. In the film which is In a state of nematic hybrid
 orientation, the refractive index ("ne" hereinafter) in a direction
 parallel to directors and the refractive index "no" hereinafter) in a
 direction perpendicular to directors are different from each other.
 Assuming that the value obtained by subtracting no from ne is an apparent
 birefringence, an apparent retardation value is given as the product of
 apparent birefringence and absolute film thickness. This apparent
 retardation value can be obtained by polarimetry such as ellipsometry.
 Apparent retardation value in the viewing angle improving film of the
 invention is usually in the range of 5 to 500 nm, preferably 10 to 300 nm,
 more preferably 15 to 150 nm. If the apparent retardation value is smaller
 than 5 nm, there substantially is no difference from homeotropic
 orientation and a satisfactory viewing angle widening effect may not be
 obtained. If it is larger than 500 nm, there may occur an unnecessary
 colorization in the liquid crystal display when the film is seen
 obliquely.
 The following description is now provided about the angle of director.
 In the thickness direction of the viewing angle improving film with nematic
 hybrid orientation fixed, the angle of director is usually in the range of
 30.degree. to 90.degree. at one of the upper and lower surfaces of the
 film in terms of an acute-side angle between director in the liquid
 crystalline polymer at a film interface and a projection component of the
 director to the film interface. On the opposite surface side the angle in
 question is usually in the range of 0.degree. to 20.degree., preferably
 40.degree. to 90.degree. as an absolute value of one angle, 0.degree. to
 10.degree. as an absolute value of the other angle.
 Now, an average tilt angle will be described below.
 In the present invention, an average value in the film thickness direction
 of angles between directors of the liquid crystalline polymer and
 projection components of the directors to the substrate surface is defined
 to be an average tilt angle. The average tilt angle can be determined by
 the application of a crystal rotation method. The average tilt angle of
 the viewing angle improving film of the invention is usually in the range
 of 10.degree. to 60.degree., preferably 20.degree. to 50.degree.. If the
 average tilt angle is smaller than 10.degree. or larger than 60.degree.,
 it may be impossible to obtain a satisfactory viewing angle widening
 effect although a certain degree of a viewing angle widening effect will
 be obtained.
 A concrete description will now be given about in what position the viewing
 angle improving film is to be disposed when the film is to be used for
 widening the viewing angle of a TN-LCD. One or plural such films may be
 disposed between a polarizing plate and a liquid crystal cell. In the
 present invention it is desirable from the standpoint of practical use
 that one or two such films be used for compensation purpose. The use of
 three or more such films cannot be said so desirable because it leads to
 an increase of cost although it will be possible to effect compensation.
 Reference will be made below to concrete positions where the film is to be
 disposed, which positions, however, are typical examples, with no
 limitation made thereto.
 First, upper and lower surfaces of the viewing angle improving film are
 defined as follows.
 The film surface at which the angle between director in the liquid
 crystalline polymer exhibiting an optically uniaxial property and the film
 surface is in the range of 30.degree. to 90.degree. on an acute angle
 side, is assumed to be surface b, while the film surface at which the said
 angle is in the range of 0.degree. to 20.degree. on an acute angle side,
 is assumed to be surface c.
 Next, the tilt direction of the viewing angle improving film is defined as
 follows.
 When the surface c of the film is seen from the surface b through the
 liquid crystal layer, the direction in which the angle between director
 and a projection component of the director to the surface c is acute and
 which is parallel to the projection component, is defined to be the tilt
 direction.
 A pretilt direction of a liquid crystal cell is defined as follows. A
 driving low-molecular liquid crystal is usually not parallel to a liquid
 crystal cell interface but tilts at a certain angle, which angle is
 defined to be a pretilt angle. The direction in which the angle between
 director of the liquid crystal at a cell interface and a projection
 component of the director to the interface is acute and which is parallel
 to the projection component of the direction, is defined to be a pretilt
 direction.
 The following description is now provided about incorporating a single
 viewing angle improving film of the invention into a TN-LCD on the basis
 of the above definitions. The film is disposed between a polarizing plate
 and a liquid crystal cell. It is optional whether the film is to be
 located on the upper surface side or the lower surface side of the cell.
 In disposing the film, it is desirable that the tilt direction of the film
 and the pretilt direction at the liquid crystal cell interface not
 adjacent to the film is substantially coincident with each other. The
 angle between the tilt direction and the pretilt direction is, as an
 absolute value, usually in the range of 0.degree. to 15.degree.,
 preferably 0.degree. to 10.degree., more preferably 0.degree. to
 5.degree.. If the said angle is larger than 15.degree., it may be
 impossible to obtain a satisfactory viewing angle compensating effect.
 Reference will now be made to the case where two viewing angle improving
 films are used in a TN-LCD.
 The two films are disposed on the upper surface and/or the lower surface of
 a liquid crystal cell located between a pair of upper and lower polarizing
 plates. It is optional whether the two films are to be located on the same
 side or respectively on the upper and lower sides. It is also optional
 whether the two films are of the same parameters or of different
 parameters.
 In the case where two viewing angle improving films are disposed
 respectively in upper and lower positions of a liquid crystal cell, it is
 desirable to dispose them in the same condition as in the case of using
 only one such film which has been referred to above. That is, it is
 desirable that in each of the two films the tilt direction of the liquid
 crystalline composition and the pretilt direction of the cell liquid
 crystal at the cell interface not adjacent to the film are substantially
 coincident with each other. The angle between the tilt direction and the
 pretilt direction is, as an absolute value, usually in the range of
 0.degree. to 15.degree., preferably 0.degree. to 10.degree., more
 preferably 0.degree. to 5.degree..
 In the case where two viewing angle improving films are disposed on either
 the upper or the lower surface of a liquid crystal cell, the film located
 closer to the cell is disposed in the same condition as in the case of
 using one such film. That is, it is desirable that the tilt direction of
 the one film and the pretilt direction of nematic liquid crystal at the
 cell interface not adjacent to the film are substantially coincident with
 each other. The angle between the tilt direction and the pretilt direction
 is, as an absolute value, usually in the range of 0.degree. to 15.degree.,
 preferably 0.degree. to 10.degree., more preferably 0.degree. to
 5.degree., The other film is disposed between the one film and a
 polarizing plate. In this case, it is desirable to dispose the other film
 so that the pretilt direction of nematic liquid crystal at the liquid
 crystal cell interface adjacent to the one first and the tilt direction of
 the other film are substantially coincident with each other.
 Since the viewing angle improving film of the invention has a nematic
 hybrid orientation, its upper and lower portions are not equivalent to
 each other. Therefore, when the film is loaded into the liquid crystal
 cell, a slight difference is recognized in the viewing angle improving
 effect, depending on which side of the film is located closer to the cell.
 More preferably, the film is actually loaded into a TN-LCD in such a
 manner that a surface of the film where the angle between director in the
 liquid crystalline polymer and the film surface is larger (the surface
 where the said angle is in the range of 30.degree. to 90.degree.), is
 located closer to the liquid crystal cell and remote from a polarizing
 plate.
 Reference will be made lastly to the arrangement of polarizing plates.
 Usually, in TN-LCD, upper and lower polarizing plates are disposed so that
 the respective transmission axes are orthogonal or parallel to each other.
 Where the transmission axes of upper and lower polarizing plates are
 orthogonal to each other, both polarizing plates are disposed so that the
 transmission axis of each polarizing plate and the rubbing direction of
 the liquid crystal cell closes to the polarizing plate are orthogonal or
 parallel to each other or at an angle of 45.degree.. Where a polarizing
 plate is disposed above the viewing angle improving film of the invention,
 the viewing angle improving effect will be obtained no matter in which of
 the above arrangements the polarizing plate may be. But it is most
 desirable to dispose upper and lower polarizing plates so that their
 transmission axes are orthogonal to each other. As to the relation between
 the transmission axis of a polarizing plate and the rubbing direction of
 the liquid crystal cell on the side closer to the polarizing plate, both
 parallel and perpendicular relations will do although there will be a
 slight difference in the viewing angle improving effect.
 The viewing angle improving film of the present invention is greatly
 effective in improving the viewing angle of TN-LCDs using TFT or MIM
 elements and is also effective in improving the viewing angle and color
 compensation of other modes of LCDs such as STN (Super Twisted
 Nematic)-LCD, ECB (Electrically Controlled Birefringence)-LCD, OMI
 (Optical Mode Interference)-LCD, OCB (Optically Compensated
 Birefringence)-LCD, HAN (Hyrid Aligned Nematic)-LCD, and IPS (In Plane
 Switching)-LCD.
 As described above, the film for optical elements according to the present
 invention fully satisfies reliability requirements such as high resistance
 to heat, to moisture and to light. Its strength is also high. Further, a
 wide range of conditions can be adopted for the orienting treatment, and
 the film, with little irregularity and few orientation defects, can be
 obtained industrially. Thus, its industrial application value is extremely
 high.
 EXAMPLES
 Examples will be described below, but it is to be understood that the
 invention is not limited thereto. The following analyzing methods were
 adopted in the Examples.
 (1) Determining the Composition of a Liquid Crystalline Polymer and the
 Structure of a Compound
 A liquid crystalline polymer was dissolved in deuterated chloroform or
 deuterated trifluoroacetic acid and the composition thereof was determined
 by .sup.1 H-NMR of 400 MHz (JNM-GX400, a product of Japan Electron Optics
 Laboratory Co., Ltd.)
 (2) Determining an Inherent Viscosity
 Using a Ubbelohde's viscometer, an inherent viscosity was determined in a
 mixed phenol/tetrachloroethane (60/40 weight ratio) solvent at 30.degree.
 C.
 (3) Determining a Liquid Crystal Phase Series
 Determined using a DSC (Perkin Elmer DSC-7) and by observation through an
 optical microscope (a polarizing microscope BH2, a product of Olympus
 Optical Co., Ltd.).
 (4) Refractive Index
 Determined using an Abbe's refractometer (Type-4, a product of Atago K.K.).
 (5) Polarization Analysis
 Conducted using an ellipsometer DVA-36VWLD (a product of Mizoshiri Kogaku
 Kogyo K.K.).
 (6) Film Thickness
 Measured using SURFACE TEXTURE ANALYSIS SYSTEM Dektak 3030ST (a product of
 SLOAN). There also was adopted a method of determining the film thickness
 by interference wave measurement (an ultraviolet, visible, near infrared
 spectrophotometer V-570, a product of Nippon Bunko K.K.) and on the basis
 of refractive index data.
 Reference Example 1
 Using 40 mmols of terephthalic acid, 40 mmols of
 2,6-naphthalenedicarboxylic acid, 80 mmols of catechol diacetate, and 80
 mmols of acetoxybenzoic acid, polymerization was carried out in a nitrogen
 atmosphere at 260.degree. C. for 4 hours, at 290.degree. C. for 2 hours,
 and then at 290.degree. C. for 4 hours in a current of nitrogen gas fed at
 a rate of 100 ml/min, to afford a liquid crystalline polyester (formula
 1). This liquid crystalline polyester had an inherent viscosity of 0.16,
 had a nematic phase as a crystal phase, and had an isotropic phase--liquid
 crystal phase transition temperature of not lower than 300.degree. C. and
 a glass transition point of 120.degree. C.
 Using this liquid crystalline polyester, there was prepared a 10 wt %
 solution thereof in a mixed phenol/tetrachloroethane solution (6/4 weight
 ratio) solvent. This solution was then applied onto a soda glass plate in
 accordance with a bar coating method, then dried, heat-treated at
 190.degree. C. for 30 minutes, and thereafter cooled at room temperature
 to fix the resulting orientation. As a result, there was obtained a liquid
 crystalline film having a thickness of 1 .mu.m. By observation of the film
 under a polarizing microscope there was found out a portion where a
 discrimination line was present despite of the same quenching axes of
 adjacent domains, and thus the orientation obtained was found to be a tilt
 orientation.
 Formula 1
 ##STR12##
 Reference Example 2
 Using 10 mmols of 4-octyloxybenzoic acid, 50 mmols of terephthalic acid, 45
 mmols of naphthalenedicarboxylic acid, 50 mmols of catechol diacetate, 50
 mmols of 3-methylcatechol diacetate, and 50 mmols of 4-acetoxybenzoic
 acid, a deacetylation polymerization was carried out in a nitrogen
 atmosphere at 270.degree. for 4 hours, and then at the same temperature
 for 2 hours in a current of nitrogen gas fed at a rate of 30 ml/min. The
 resulting reaction product was then dissolved in tetrachloroethane and
 thereafter purified by reprecipitation with methanol to afford a liquid
 crystalline polyester (formula 2). This liquid crystalline polyester had
 an inherent viscosity of 0.10, had a nematic phase as a liquid crystal
 phase, and had an isotropic phase-liquid crystal phase transition
 temperature of 240.degree. C. and a glass transition point of 75.degree.
 C.
 Using the liquid crystalline polyester, there was prepared a 10 wt %
 solution thereof in a mixed phenol/tetrachloroethane (6/4 weight ratio)
 solvent. The solution was then applied onto a soda glass plate by a spin
 coaing method, then dried, heat-treated at 220.degree. C. for 30 minutes,
 and thereafter cooled at room temperature to fix the resulting
 orientation. As a result of conoscope observation of the film, the film
 was found to have a homeotropic orientation.
 Formula 2
 ##STR13##
 Reference Example 3
 10 mmols of tert-butylhydroquinone diacetate and 20 mmols of
 1,6-pentyloxy-2-naphthoic acid were reacted in a nitrogen atmosphere at
 250.degree. C. for 4 hours, at 270.degree. C. for 2 hours, and then at
 27.degree. C. for 2 hours in a current of nitrogen gas fed at a rate of 30
 ml/min. Subsequent recrystallization of the resulting reaction product
 from a mixed methanol/ethyl acetate (1/1) solvent afforded the compound of
 formula (3).
 Formula 3
 ##STR14##
 Example 1
 75 parts of the liquid crystalline polyester (formula 1), 20 parts of the
 liquid crystalline polyester (formula 2), and 5 parts of the compound
 (formula 3), prepared in the above reference examples, were mixed together
 to afford a liquid crystalline composition. Then, there was prepared an 8
 wt % solution of the said composition in tetrachloroethane. This solution
 was then applied onto a glass substrate having a rubbed polyimide film by
 a spin coating method, then dried, heat-treated at 220.degree. C. for 20
 minutes, and thereafter cooled with air, to afford film 1. The film 1 on
 the glass substrate was a uniform, transparent film free of any
 orientation defect and having a thickness of 1.55 .mu.m.
 Then, using an optical measurement system shown in FIGS. 1 and 2, a
 retardation value of the film was measured while the film was tilted in
 the rubbing direction of the substrate. The result proved to be asymmetric
 right and left as in FIG. 3 and include no angle corresponding to a
 retardation value of zero. From this result it turned out that the
 directors of the liquid crystalline polyesters tilted with respect to the
 substrate and that the orientation obtained was not a uniform tilt
 orientation (a state of orientation in which the director-substrate
 surface angle is constant in the film thickness direction).
 The film 1 on the substrate was cut into five divided films, each of which
 was then dipped in a methanol solution containing 3 wt % of chloroform for
 a predetermined certain time, allowing elution to take place from the
 upper surface of the liquid crystal layer. When the films were dipped for
 15 seconds, 30 seconds, 1 minute, 2 minute and 5 minutes, respectively,
 the thicknesses of their liquid crystal layers left uneluted were 1.35
 .mu.m, 1.10 .mu.m, 0.88 .mu.m, 0.56 .mu.m, and 0.37 .mu.m, respectively.
 Using the optical system shown in FIGS. 1 and 2, retardation values (front
 retardation values) at .theta.=0.degree. were measured and there was
 obtained such a film thickness--retardation value relation as shown in
 FIG. 4. As is seen from the same figure, the film thicknesses and the
 retardation values are not in a linear relation, thus indicating that the
 orientation obtained is not a uniform tilt orientation. The dotted line in
 the figure is a straight line which is usually observed in a film of
 uniform tilt orientation.
 Then, in the same way as above, the above liquid crystalline composition
 was oriented and orientation-fixed on a glass substrate of a high
 refractive index (1.84) having a rubbed polyimide film, to prepare film
 1'. Using the film 1', there was made a refractive index measurement.
 The film 1' was disposed in such a manner that the glass substrate came
 into contact with a prism surface of the refractometer and that the
 substrate interface side of the film was positioned below the air
 interface side thereof. In this case, intra-film surface refractive
 indices were anisotropic. The refractive index in a surface perpendicular
 to the rubbing direction was 1.55 and the refractive index in a surface
 parallel to the rubbing direction was 1.71. Further, the refractive index
 in the film thickness direction was 1.55 independently of the film
 direction. Thus, it turned out that, on the glass substrate side, rod-like
 liquid crystal molecules constituting the liquid crystalline polyesters
 were oriented planarly in parallel with the substrate. Next, the film was
 disposed in such a manner that its air interface side came into contact
 with the prism surface of the refractometer. In this case, no anisotropy
 was found in intra-film surface refractive indices, and there was observed
 a constant refractive index of 1.55. Also in the film thickness direction
 there was observed a constant refractive index of 1.71 independently of
 the direction of the film 1'. Thus, it turned out that, on the air
 interface side of the film, rod-like liquid crystal molecules of the
 liquid crystalline polyesters were oriented perpendicularly to the
 substrate surface.
 The above results show that the film obtained in this Example has such a
 nematic hybrid orientation as shown in FIG. 5 and that the orientation is
 ensured with a restricting force of the substrate interface induced by
 rubbing and that of the air interface.
 Next, the following operation was performed to determine the angle of
 director direction at the substrate interface more accurately.
 Another glass substrate having a rubbed polyimide film was brought into
 close contact with the upper surface of the film 1' formed on the above
 high refractive index glass substrate having a rubbed polyimide film. That
 is, the film 1' was sandwiched in between two rubbed polyimide films. In
 this case, both glass substrates were disposed so that the rubbing
 directions of the upper and lower rubbed films were at 180.degree.
 relative to each other. In this state there was made heat treatment at
 190.degree. C. for 30 minutes. The sample film thus obtained was then
 subjected to refractive index measurement and polarization analysis. As a
 result of the refractive index measurement there was obtained the same
 value for both upper and lower surfaces of the sample film. Intra-film
 surface refractive indices were 1.55 in a plane perpendicular to the
 rubbing direction, 1.71 in a plane parallel to the rubbing direction, and
 1.55 in the film thickness direction. From this result it turned out that,
 in the vicinity of substrate interfaces, directors were nearly parallel to
 substrate surfaces in both upper and lower portions of the sample film.
 Further, as a result of polarization analysis, the sample film proved to
 have a substantially uniaxial refractive index structure. On this regard,
 a detailed ananlysis was made in accordance with a crystal rotation
 method. As a result, a slight tilt of director was observed in the
 vicinity of a substrate interface and the director-substrate surface angle
 was about 3.degree.. Further, the tilting direction of the director was
 coincident with the rubbing direction (the film tilt direction and the
 rubbing direction coincide with each other).
 From the above results it is presumed that the direction of director at a
 substrate interface is determined substantially by an interaction between
 the liquid crystalline polyesters and an orienting substrate interface.
 Consequently, the direction of director at a substrate interface in the
 nematic hybrid orientation of each of the films 1 and 1' formed on a
 single orienting substrate described above is presumed to be a direction
 of 3.degree. relaltive to the substrate interface.
 Example 2
 There was prepared a solution in tetrachloroethane containing 8 wt % of the
 same liquid crystalline composition as that in Example 1. The solution was
 applied onto a glass substrate having a rubbed polyimide film by a spin
 coating method and then dried, followed by heat treatment at 210.degree.
 C. for 10 minutes and subsequent cooling, to afford film 2. The film 2 on
 the substrate was transparent and uniform, involving no orientation
 defect. The film thickness was 0.42 .mu.m and an average tilt angle in the
 film thickness direction was 36.degree..
 Using two films 2, optical elements were disposed in such an axial
 configuration as shown in FIG. 6. At this time, the films 2 were disposed
 respectively above and below a liquid crystal cell. The liquid crystal
 cell, which was formed using a liquid crystal material ZLI-4792, had such
 cell parameters as a cell gap of 4.8 .mu.m, a twist angle of 90.degree.
 (left-hand twist) and a pretilt angle of 4.degree.. A voltage was applied
 to the liquid crystal cell using a square wave of 300 Hz. With the ratio
 in transmittance of white display OV to black display 6V, (white
 display)/(black display), as contrast ratio, contrast ratios in all
 directions were measured using an FFP optical system, DVS-3000 (a product
 of Hamamatsu Photonics Co.), to describe equicontrast curves, the results
 of which are shown in FIG. 7.
 Such a voltage as divides the difference in transmittance between white
 display and black display into eight equal parts in the configuration of
 FIG. 6, was applied to the liquid crystal cell and gradation
 characteristics in a lateral direction (0.degree.-180.degree. direction)
 were measured using a color luminance meter BM-5 (a product of Topcon
 Co.), the results of which are shown in FIG. 8.
 Comparative Example 1
 Using the same TN type liquid crystal cell as in Example 2 and under the
 same conditions as in Example 2 except that the film 2 was not used,
 contrast ratios were measured in all directions and gradation
 characteristics were measured in the lateral direction
 (0.degree.-180.degree. direction), the results of which are shown in FIGS.
 9 and 10.
 Reference Example 4
 22 mmols of 4-(2-ethylhexyloxy)phenol was dissolved in 500 ml of pyridine,
 and a solution of 10 mmols terephthalic acid dichloride in 200 ml
 methylene chloride was added dropwise at 0.degree. C. over a period of 30
 minutes while stirring was conducted using a mechanical stirrer. Reaction
 was allowed to take place at 0.degree. C. for 2 hours and at room
 temperature for 5 hours, thereafter, pyridine was distilled off under
 reduced pressure. Then, 500 ml of 1N hydrochloric acid was added to the
 residue, followed by extraction with ethyl acetate. The extract was washed
 again with IN hydrochloric acid, then washed with water, aqueous sodium
 bicarbonate, and saturated aqueous NaCl successively in this order. The
 extract was then dried over magnesium sulfate and the solvent was
 distilled off, then the residue was recrystallized from a mixed
 methanol/ethyl acetate solvent, to afford a compound of formula 4.
 Formula 4
 ##STR15##
 Example 3
 70 parts of the liquid crystalline polyester (formula 1), 27 parts of the
 liquid crystalline polyester (formula 2), and 3 parts of the compound
 (formula 4), prepared in the above Reference Examples 1, 2 and 4,
 respectively, were mixed together to prepare a liquid crystalline
 composition.
 Then, a 10 wt % solution of this composition in N-methylpyrrolidone was
 prepared. Further, for lowering the surface tension of the solution, KH-40
 (a product of Asahi Glass Co.) was added 0.005% based on the total weight
 of the solution.
 Coating, drying and heat treatment were conducted under the same conditions
 as in Example 2 to prepare film 3.
 The film 3 had a thickness of 0.50 .mu.m and an average tilt angle in the
 film thickness direction of 30.degree.. Using this film, contrast ratios
 were measured in all directions in the same manner as in Example 2, the
 results of which are shown in FIG. 11.
 Reference Example 5
 Using 20 mmols of 4-benzyloxybenzoic acid and 10 mmols of catechol
 diacetate, a deacetylation reaction was conducted in a nitrogen atmosphere
 at 270.degree. C. for 4 hours, and then at the same temperature for 2
 hours in a current of nitrogen gas fed at a rate of 30 ml/min. The
 resulting reaction product was dissolved in tetrachloroethane and
 subsequent reprecipitation using methanol afforded a compound of formula
 5.
 Formula 5
 ##STR16##
 The compound thus prepared was then dissolved in 500 ml of ethyl acetate
 and the resulting solution was subjected to a hydrogenolysis reaction in a
 hydrogen atmosphere of 2 atm. at room temperature for 2 hours together
 with 1 g of 5% Pd/C catalyst, allowing the benzyl group to split off.
 Then, the reaction product was dissolved in a mixture of 500 ml methylene
 chloride with 1 g of dimethylaminopyridine added thereto and 100 ml of
 pyridine, and a solution of 20 mmols 4-octyloxybenzoic acid chloride in
 200 ml methylene chloride was added dropwise at 0.degree. over a 30-minute
 period. Reaction was allowed to take place at 0.degree. C. for 2 hours and
 at room temperature for 5 hours, thereafter, pyridine was distilled off
 under reduced pressure. 500 ml of 1N hydrochloric acid was added to the
 residue, followed by extraction with ethyl acetate. The extract was washed
 again with IN hydrochloric acid and then washed with water, aqueous sodium
 bicarbonate, and saturated aqueous NaCl successive in this order. The
 extract was then dried over magnesium sulfate and thereafter the solvent
 was distilled off. Subsequently, the residue was dissolved in chloroform
 and the resulting solution was subjected to reprecipitation with methanol
 to afford a compound of formula 6.
 Formula 6
 ##STR17##
 Reference Example 6
 20 mmols of 2-benzyloxyphenol was dissolved in 500 ml of pyridine and a
 solution of 10 mmols 4,4'-oxybis(benzoic acid dichloride) in 200 ml
 methylene chloride was added dropwise over a 30-minute period. Reaction
 was allowed to take place at 0.degree. C. for 2 hours and at room
 temperature for 5 hours, thereafter, pyridine was distilled off under
 reduced pressure. 500 ml of 1N hydrochloric acid was added to the residue,
 followed by extraction with ethyl acetate. The extract was washed again
 with iN hydrochloric acid and then washed with water, aqueous sodium
 bicarbonate, and saturated aqueous NaCl successively in this order. The
 extract was then dried over magnesium sulfate and thereafter the solvent
 was distilled off. The resulting residue was recrystallized using a mixed
 methanol/ethyl acetate solvent to afford a compound of formula 7.
 Formula 7
 ##STR18##
 The compound thus prepared was then dissolved in 500 ml of ethyl acetate
 and the resulting solution was subjected to a hydrogenolysis reaction in a
 hydrogen atmosphere of 2 atm. at room temperature for 24 hours together
 with 1 g of 5% Pd/C catalyst, allowing the benzyl group to split off. The
 reaction product was then dissolved in a mixture of 500 ml methylene
 chloride with 1 g of dimethylaminopyridine added thereto and 100 ml
 pyridine, and a solution of 20 mmols 4'-butoxystilbene-4-carboxylic acid
 chloride in 200 ml methylene chloride was added dropwise over a 30-minute
 period at 0.degree. C. Reaction was allowed to take place at 0.degree. C.
 for 2 hours and at room temperature for 5 hours, thereafter, pyridine was
 distilled off under reduced pressure. 500 ml of 1N hydrochloric acid was
 added to the residue, followed by extraction with ethyl acetate. The
 extract was washed again with IN hydrochloric acid and then washed with
 water, aqueous sodium bicarbonate, and saturated aqueous NaCl successively
 in this order. Then, the extract was dried over magnesium sulfate and
 thereafter the solvent was distilled off. Subsequently, the residue was
 dissolved in N-methylpyrrolidone and the resulting solution was subjected
 to reprecipitation with methanol to afford a compound of formula 8.
 Formula 8
 ##STR19##
 Reference Examples 7.about.18
 100 mmols of a compound X in Table 1 and 20 mmols of a compound Y in the
 same table were mixed together and reaction was allowed to take place in a
 nitrogen atmosphere at 250.degree. C. for 4 hours, at 270.degree. C. for 2
 hours, and subsequently at 270.degree. for 2 hours in a current of
 nitrogen gas fed at a rate of 30 ml/min. As to compounds (11), (13), (15),
 (16), (17) and (20), they were purified by recrystallization from a mixed
 methanol/ethyl acetate-(1/1) solvent. On the other hand, as to compounds
 (9), (10), (12), (14), (18) and (19), they were purified by dissolving
 crude products in chloroform and subsequent dropwise addition into
 methanol and reprecipitation of products.
 TABLE 1
 Reference Com-
 Example pound X Y
 7 (9) bisphenol 4-hexyloxy-
 A-diacetate benzoic acid
 8 (10) resorcinol 5-hexyloxy-2-
 diacetate naphthoic acid
 9 (11) 1,4-diacetoxy- 4-pentyloxy
 naphthalene cinnamic acid
 10 (12) 1,8-diacetoxy (.+-.)-4-methyloxy
 naphthalene benzoic acid
 11 (13) hydroquinone 3-heptyloxy
 diacetate benzoic acid
 12 (14) methylhydro- 3,4-dipentyloxy
 quinone diacetate benzoic acid
 13 (15) methylhydro- 4-octyloxy
 quinone diacetate benzoic acid
 14 (16) 4,4'-diacetoxy 3-octyloxy
 biphenyl benzoic acid
 15 (17) catechol 4-hexyloxy
 cinnamic acid
 16 (18) 3-methyl 4-pentyloxyphenyl
 catechol acetic acid
 17 (19) 3-tert-butyl tert-butyl
 catechol benzoic acid
 18 (20) chlorohydro- 4-pentyloxyphenyl
 quinone acetic acid
 Formula 9 (Compound 9)
 ##STR20##
 Formula 10 (Compound 10)
 ##STR21##
 Formula 11 (Compound 11)
 ##STR22##
 Formula 12 (Compound 12)
 ##STR23##
 Formula 13 (Compound 13)
 ##STR24##
 Formula 14 (Compound 14)
 ##STR25##
 Formula 15 (Compound 15)
 ##STR26##
 Formula 16 (Compound 16)
 ##STR27##
 Formula 17 (Compound 17)
 ##STR28##
 Formula 18 (Compound 18)
 ##STR29##
 Formula 19 (Compound 19)
 ##STR30##
 Formula 20 (Compound 20)
 ##STR31##
 Reference Examples 19.about.25
 200 ml of a compound X in Table 2 was dissolved in 500 ml of pyridine and a
 solution of a compound Y in the same table dissolved in 200 ml methylene
 chloride was added dropwise over a 30-minute period at 0.degree. C. while
 stirring was conducted using a a mechanical stirrer. Reaction was allowed
 to take place at 0.degree. C. for 2 hours and at room temperature for 5
 hours, thereafter, pyridine was distilled off under reduced pressure. 500
 ml of 1N hydrochloric acid was added to the residue, followed by
 extraction with ethyl acetate. The extract was washed again with 1N
 hydrochloric acid and then washed with water, aqueous sodium bicarbonate,
 and saturated aqueous NaCl successively in this order. The extract was
 then washed over magnesium sulfate and the solvent was distilled off.
 Therafter, as to compounds (21), (23), (25), (26) and (27), they were
 purified by recrystallization from a mixed methanol/ethyl acetate (1/1)
 solvent. On the other hand, as to compounds (22) and (24), they were
 purified by dissolving crude products in chloroform and subsequent
 addition into methanol and reprecipitation of products.
 TABLE 2
 Reference Com-
 Example pound X Y
 19 (21) 2,4-dibutoxy 4-hexylphenol
 benzoic
 dichloride
 20 (22) isophthalic 4-octyloxyphenol
 dichloride
 21 (23) terephthalic 4-benzyloxy-1-
 dichloride naphthol
 22 (24) 2,6-naphthalene nonylphenol
 dicarboxylic
 dichloride
 23 (25) trans-1,4-cyclo- 4-hexylphenol
 hexane dicarbo-
 xylic dichloride
 24 (26) terephthalic 4-hexyloxybenzyl
 dichloride alcohol
 25 (27) 4,4'-oxybis 4-hexyloxyphenol
 (benzoic chloride)
 Formula 21 (Compound 21)
 ##STR32##
 Formula 22 (Compound 22)
 ##STR33##
 Formula 23 (Compound 23)
 ##STR34##
 Formula 24 (Compound 24)
 ##STR35##
 Formula 25 (Compound 25)
 ##STR36##
 Formula 26 (Compound 26)
 ##STR37##
 Formula 27 (Compound 27)
 ##STR38##
 Examples 4.about.34
 Films were prepared in the same way as in Example 3 and then evaluated, the
 results of which are shown in Table 3.
 TABLE 3
 Orien- View-
 tation Ave- ing
 LC Composition .largecircle.: rage
 Angle
 Additive LC Polymer uni- Thick- Tilt Compen-
 Amount (parts) form ness Angle tion
 Ex. No. Compd. (parts) (1) (2) defects (.mu.m) (deg.) Effect
 4 (3) 10 90 0 .largecircle. 0.70 19
 .largecircle.
 5 (3) 10 81 9 .largecircle. 0.50 25
 .largecircle.
 6 (3) 10 63 27 .largecircle. 0.40 33
 .largecircle.
 7 (4) 5 85 10 .largecircle. 0.51 27
 .largecircle.
 8 (5) 5 65 30 .largecircle. 0.53 33
 .largecircle.
 9 (6) 5 65 30 .largecircle. 0.57 32
 .largecircle.
 10 (7) 5 65 30 .largecircle. 0.54 34
 .largecircle.
 11 (8) 5 65 30 .largecircle. 0.49 33
 .largecircle.
 12 (9) 5 65 30 .largecircle. 0.53 31
 .largecircle.
 13 (10) 5 65 30 .largecircle. 0.57 36
 .largecircle.
 14 (11) 5 65 30 .largecircle. 0.77 34
 .largecircle.
 15 (11) 3 65 32 .largecircle. 0.75 34
 .largecircle.
 16 (12) 5 65 30 .largecircle. 0.66 36
 .largecircle.
 17 (13) 5 65 30 .largecircle. 0.63 34
 .largecircle.
 18 (14) 5 65 30 .largecircle. 0.59 32
 .largecircle.
 19 (15) 5 65 30 .largecircle. 0.60 35
 .largecircle.
 20 (16) 5 65 30 .largecircle. 0.61 31
 .largecircle.
 21 (17) 5 65 30 .largecircle. 0.62 33
 .largecircle.
 22 (18) 5 65 30 .largecircle. 0.58 35
 .largecircle.
 23 (19) 5 65 30 .largecircle. 0.55 29
 .largecircle.
 24 (20) 5 65 30 .largecircle. 0.54 34
 .largecircle.
 25 (21) 5 65 30 .largecircle. 0.57 35
 .largecircle.
 26 (22) 5 65 30 .largecircle. 0.60 36
 .largecircle.
 27 (23) 5 65 30 .largecircle. 0.53 29
 .largecircle.
 28 (24) 5 65 30 .largecircle. 0.61 30
 .largecircle.
 29 (25) 5 65 30 .largecircle. 0.62 33
 .largecircle.
 30 (26) 5 65 30 .largecircle. 8.61 31
 .largecircle.
 31 (27) 5 65 30 .largecircle. 0.66 34
 .largecircle.
 32 (28) 5 65 30 .largecircle. 0.62 36
 .largecircle.
 33 (29) 5 65 30 .largecircle. 0.64 35
 .largecircle.
 34 (30) 5 65 30 .largecircle. 0.67 37
 .largecircle.
 Com. Ex. 2 . . . . 100 0 X 0.70 21 --
 Com. Ex. 3 . . . . 90 10 X 0.50 26 --
 Com. Ex. 4 . . . . 70 30 X 0.40 35 --
 Compound 28: didecyl-4,4'-biphenyldicarboxylate
 Compound 29: 4,4'-didodecyloxy- -methylstylbene
 Compound 30: (4-hexylphenyl)-4-octyloxybenzoate