Claims
        
                - 1. An optically active compound having the formula (1): ##STR65## wherein R and R' are the same or different alkyl groups containing 1 to 20 carbon atoms, which are each unsubstituted or are each substituted with at least one substituent selected from the group consisting of F, Cl and alkoxy groups; X is a direct bond, O, S, COO, OCO, OCOO or C.tbd.C; Y.sub.1 is COO, O, CH.sub.2 O or C.tbd.C; A.sub.1 is 1,4-phenylene (ph), fluoro-substituted 1,4-phenylene, or 2,5-pyridylene (pyr) and m is 1 Nt represents 2,6-naphthylene.
 
                - 2. The compound of claim 1, wherein at least one of R and R' is an optically active alkyl group which is unsubstituted or is substituted with F, Cl or an alkoxy group.
 
                - 3. The compound of claim 1, wherein X is a direct bond or O.
 
                - 4. The compound of claim 1, wherein Y.sub.1 is --COO--.
 
                - 5. The compound of claim 1, wherein X is a direct bond.
 
                - 6. The compound of claim 1, wherein A.sub.1 is Ph.
 
                - 7. The compound of claim 5, wherein Y.sub.1 is --COO--.
 
                - 8. The compound of claim 6, wherein Y.sub.1 is --COO--.
 
                - 9. The compound of claim 5, wherein A.sub.1 is Ph.
 
                - 10. The compound of claim 1, wherein A.sub.1 is Ph.
 
                - 11. The compound of claim 9, wherein Y.sub.1 is --COO--.
 
                - 12. The compound of claim 8, wherein X is a direct bond or oxygen.
 
                - 13. The compound of claim 7, wherein A.sub.1 is Ph or fluoro substituted Ph or 2,5-pyridylene.
 
                - 14. The compound of claim 9, wherein Y.sub.1 is --COO--, --O--, --CH.sub.2 O-- or --C.tbd.C--.
 
        
                        Priority Claims (8)
        
            
                
                    | Number | 
                    Date | 
                    Country | 
                    Kind | 
                
            
            
                    
                        | 1-47948 | 
                        Feb 1989 | 
                        JPX | 
                         | 
                    
                    
                        | 1-47949 | 
                        Feb 1989 | 
                        JPX | 
                         | 
                    
                    
                        | 1-49468 | 
                        Mar 1989 | 
                        JPX | 
                         | 
                    
                    
                        | 1-49469 | 
                        Mar 1989 | 
                        JPX | 
                         | 
                    
                    
                        | 1-49470 | 
                        Mar 1989 | 
                        JPX | 
                         | 
                    
                    
                        | 1-192061 | 
                        Jul 1989 | 
                        JPX | 
                         | 
                    
                    
                        | 1-299928 | 
                        Nov 1989 | 
                        JPX | 
                         | 
                    
                    
                        | 1-303851 | 
                        Nov 1989 | 
                        JPX | 
                         | 
                    
            
        
                        Parent Case Info
        This is a division of U.S. patent application Ser. No. 07/486,008, filed on Feb. 27, 1990, now U.S. Pat. No. 5,160,662.
                
                
                
                            US Referenced Citations (2)
            
                
                    
                        | Number | 
                        Name | 
                        Date | 
                        Kind | 
                    
                
                
                        
                            | 
4576732                             | 
                            Isogai et al. | 
                            Mar 1986 | 
                             | 
                        
                        
                            | 
4613209                             | 
                            Goodby et al. | 
                            Sep 1986 | 
                             | 
                        
                
            
            Foreign Referenced Citations (4)
            
                
                    
                        | Number | 
                        
                        Date | 
                        Country | 
                    
                
                
                        
                            | 293910 | 
                            
                            Dec 1988 | 
                            EPX | 
                        
                        
                            | 294852 | 
                            
                            Dec 1988 | 
                            EPX | 
                        
                        
                            | 62-169883 | 
                            
                            Jul 1987 | 
                            JPX | 
                        
                        
                            | 8909764 | 
                            
                            Oct 1989 | 
                            WOX | 
                        
                
            
            Non-Patent Literature Citations (4)
            
                
                    
                        | Entry | 
                    
                
                
                        
                            | Liquid Crystals and Ordered Fluids, vol. 4, pp. 1-32, Goodby et al., "Some Novel Ferroelectric Smectic Liquid Crystals". | 
                        
                        
                            | Chem. Abst., vol. 110, No. 11 Mar. 13, 1989, p. 656, Abst. No. 94711x. | 
                        
                        
                            | Mol. Cryst. Liq. Cryst. 1984, vol. 110, pp. 175-203, Goodby et al. Ferroelectric Liquid Crystals-Structure and Design. | 
                        
                        
                            | Synthesis, Journal of Synthetic Organic Chemistry, No. 8, Aug. 1986, pp. 605-692. | 
                        
                
            
                        Divisions (1)
        
            
                
                     | 
                    Number | 
                    Date | 
                    Country | 
                
            
            
    
        | Parent | 
            486008 | 
        Feb 1990 | 
         |