Claims
- 1. An optically active compound expressed by the formula ##STR37## wherein R.sup.1 represents an alkyl group 2-12 carbon atoms, R.sup.2 represents an alkyl group of 3-8 carbon atoms, and * represents an unsymmetric carbon atom.
- 2. A liquid crystal composition comprising at least two components at least one of which is an optically active compound of the formula (I) as set forth in claim 1.
- 3. A liquid crystal composition according to claim 2, exhibiting chiral smectic phase.
- 4. A liquid crystal composition according to claim 2, exhibiting chiral nematic phase.
- 5. A liquid crystal display element containing a liquid crystal composition which comprises at least two components at least one of which is an optically active compound of the formula (I) as set forth in claim 1 and exhibits chiral smectic phase.
Priority Claims (2)
| Number |
Date |
Country |
Kind |
| 61-267206 |
Nov 1986 |
JPX |
|
| 61-313310 |
Dec 1986 |
JPX |
|
BACKGROUND OF THE INVENTION
This application is a division of now abandoned application, Ser. No. 07/119,067 filed on Nov. 10, 1987 now abandoned.
1. Field of the Invention
This invention relates to a novel compound suitable as a component of liquid crystal compositions, and more particularly it relates to a chiral compound having an optically active group and a liquid crystal composition containing the same, particularly a ferroelectric liquid crystal composition.
2. Description of the Related Art
At present, TN (twisted nematic) mode display has been most broadly employed as liquid crystal display elements, but it is inferior in the aspect of the response rate to emissive mode display elements (electroluminescence, plasma display, etc.); hence various improvements in this respect have been attempted, but it does not appear that a possibility of improvement to a large extent remains. Thus, various liquid crystal display devices based on another principle in place of that of TN mode display elements have been attempted, and as one such device, there is a display mode making use of ferroelectric liquid crystals (N. A. Clark et al, Applied Phys. lett., 36,899 (1980)). This mode makes use of chiral smectic phases such as chiral smectic C phase (hereinafter abbreviated to SC.sup.* phase), and the temperature range exhibiting these phases is preferred to be in the vicinity of room temperature. In addition, as liquid crystal phases exhibiting ferroelectricity, not only SC.sup.* phase but also chiral smectic F, G, H, I, J, etc. phases have been known.
In order to search for compounds having superior characteristics as a component of liquid crystal materials used for liquid crystal display mode making use of the ferroelectricity, the present inventors have extensively searched for a large number of compounds and have attained the present invention.
The present invention resides in: an optically active compound expressed by the formula ##STR2## wherein R.sup.1 represents an alkyl group, an alkoxy group or an alkoxycarbonyl group each of 2 to 18 carbon atoms, R.sup.2 represents an alkyl group of 3 to 18 carbon atoms or an alkoxy group of 1 to 18 carbon atoms, A represents ##STR3## wherein X represents hydrogen atom, fluorine atom, chlorine atom, cyano group, methyl group or trifluoromethyl group, and the symbol * represents an unsymmetric carbon atom, and a liquid crystal composition containing at least one of the above-mentioned optically active compounds.
US Referenced Citations (11)
Foreign Referenced Citations (6)
| Number |
Date |
Country |
| 164814 |
Dec 1985 |
EPX |
| 175591 |
Mar 1986 |
EPX |
| 63-44551 |
Feb 1988 |
JPX |
| 63-63664 |
Mar 1988 |
JPX |
| 8705012 |
Aug 1987 |
WOX |
| 8803525 |
May 1988 |
WOX |
Non-Patent Literature Citations (1)
| Entry |
| Goodby et al., Liquid Crystals & Ordered Fluids, vol. 4, pp. 1-32 (1984). |
Divisions (1)
|
Number |
Date |
Country |
| Parent |
119067 |
Nov 1987 |
|
Patent Grant
5055222
