RU97114889A - ELECTROOPTIC LIQUID CRYSTAL INDICATOR - Google Patents

Claims (13)

1. Electro-optical liquid crystal indicator with a reorientation layer for liquid crystals, the field of which has a significant component parallel to the liquid crystal layer containing a liquid crystal medium with positive dielectric anisotropy, characterized in that the medium contains
a) at least one mesogenic compound with a 3,4,5-trifluorophenyl group, and / or
b) at least one mesogenic compound, which is a structural element of formula 2

where A is O or CH;
Z is —COO— or a single bond;
L ¹ means F or, if A means O, also H;
L ² means H or F. 2. The liquid crystal indicator according to claim 1, characterized in that the medium contains at least one compound of formula I

where R ¹ means H, unsubstituted, once substituted by CN or CF ₃ or at least once substituted by halogen alkyl or alkenyl radical with 1-15 C-atoms, while in these residues also one or more CH ₂ groups, respectively, independently from each other may be substituted by —O—, —S—,

—CO — O—, —O — CO— or —O — CO — O— such that the O atoms are not directly bonded to each other;
A ¹ and A ^2, respectively, from each other mean (a) a 1,4-cyclohexenylene or trans-1,4-cyclohexylene radical in which one or more non-adjacent CH ₂ groups can be substituted by —O— and / or —S -, (b) a 1,4-phenylene residue in which one or two CH groups can be substituted with N, (c) a residue from the 1,4-bicyclo (2,2,2) -octylene group, piperidin-1, 4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, while residues (a) and (b) can be substituted with one or two fluorine atoms;
Z ¹ and Z ^2, respectively, independently of one another, mean —CO — O—, —O — CO—, —CH ₂ O—, —OCH ₂ -, —CH ₂ CH ₂ -, —CH = CH, —C

C- or single bond, one of the residues Z ¹ and Z ² also means - (CH ₂ ) ₄ - or —CH = CH — CH ₂ CH ₂ -;
m = 0, 1 or 2. 3. The liquid crystal indicator according to one of claim 1 or 2, characterized in that the medium contains at least one compound that has a group of formula 3

where L ³ and L ⁴ means H or F. 4. The liquid crystal indicator according to one of claims 1 to 3, characterized in that the medium contains at least one compound of formula II

where L ³ and L ⁴ have the indicated meanings;
R ² has the meaning indicated for R ¹ ;
A ³ and A ⁴ are respectively independently of one another the values indicated for A ¹ and A ² ;
Z ³ and Z ⁴ are respectively from each other indicated for Z ¹ and Z ² values;
n = 0, 1 or 2. 5. The liquid crystal indicator according to claim 4, characterized in that the medium contains at least one compound of formula II in which R ² , A ³ , A ⁴ , Z ³ , Z ⁴ and n have the indicated meanings, L ³ means F, and L ⁴ is H or F. 6. The liquid crystal indicator according to one of claims 1 to 5, characterized in that the medium contains at least one compound selected from formulas IIa, IIb and IIc

where respectively R ² , L ³ and L ⁴ have the indicated meanings.  7. The liquid crystal indicator according to one of claims 1 to 4, characterized in that the medium is characterized by anisotropy ΔEE> 8.5. 8. The liquid crystal indicator according to one of claims 3 to 7, characterized in that the medium contains at least one compound of formula III
R ³ - (A ⁵ -Z ⁵ ) _o -A ⁶ -R ⁴ ,
where R ³ and R ^4, respectively, independently of one another, have the meaning indicated for R ¹ ;
A ⁵ and A ⁶ are respectively independently of one another the value indicated for A ¹ and A ² ;
Z ⁵ has, respectively, independently of one another the values indicated for Z ¹ and Z ² ;
o = 1, 2 or 3. 9. The liquid crystal indicator according to one of claims 3 to 8, characterized in that the medium contains at least one compound of formula IV

where R ⁵ has the meaning indicated for R ¹ ;
A ⁷ and A ⁸ are respectively independently of one another the values indicated for A ¹ and A ² ;
Z ⁷ and Z ⁸ are respectively independently from each other indicated for Z ¹ and Z ² values;
L ⁵ and L ⁶ mean respectively independently from each other H or F;
Q means a polyfluoroalkylene residue of the formula - (O) _g - (CH ₂ ) _r - (CF ₂ ) _s -, in which g = 0 or 1, r = 0 or 1-6, s = 1-6,
X is H, F or Cl,
p = 0, 1 or 2.  10. The liquid crystal indicator according to one of claims 1 to 9, characterized in that the image elements are controlled by an active matrix.  11. A liquid crystal medium with positive dielectric anisotropy, which is the composition specified in claims 3-10.  12. The liquid crystal medium according to claim 11, characterized in that it contains 10-60 weight. %, preferably 15-40 wt.%, at least one compound of the formula I, 15-40 wt.%, preferably 20-35 wt.%, at least one compound of the formula II, 20-55 wt.%, preferably 25 -50 wt.%, At least one compound of the formula III, and 0-30 wt.%, Preferably 20-25 wt.%, At least one compound of the formula IV.  13. The liquid crystal medium according to claim 9 or 12, characterized in that it contains at least one compound selected from formulas Ia and Ib.

at least one compound selected from formulas II1, II2, II3 and II4,

at least one compound selected from formulas IIIa, IIIb and IIIc,

and if necessary, at least one compound selected from formulas 1Va and 1Vb

in which the following values hold

respectively

and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , L ¹ , L ² , L ³ , L ⁴ , L ⁵ and L ⁶ have the indicated meanings, respectively.