the liquid crystal compounds with optical activity having high helical twisting power according to the present invention can be multi - ring organic esters with optical activity represented by formula ( i ) comprising compound t1 , t2 , and t3 within the structure of optically active terpenol natural product , compound b1 , b2 , and b3 within the structure of optically active borneol natural product , compound c1 , c2 , and c3 within the structure of optically active cinchonidine natural product , and compound q1 , q2 , and q3 within the structure of optically active quinine natural product . the liquid crystal compounds with optical activity having high helical twisting power according to the present invention can also be multi - ring organic esters with optical activity represented by formula ( ii ) comprising compound t4 within the structure of optically active terpenol natural product , and compound b4 within the structure of optically active borneol natural product . the organic acid according to the present invention can be an organic acid having similar core structure to liquid crystal represented by formula ( iii ) or formula ( iv ), such as benzoic acid , cyclohexanecarboxylic acid , biphenyl carboxylic acid , para - cyclohexane - dicarboxylic acid , terephthalic acid , 4 - n - hexyloxy - benzoic acid 4 - n - propyl - cyclohexanecarboxylic acid , 4 - decyloxy - biphenyl - 4 - carboxylic acid , cyclohexane - 1 , 4 - dicarboxylic acid , or derivatives thereof . in one aspect of the present invention , the method of preparing liquid crystal compounds represented by formula ( i ) comprises providing an organic acid , such as 4 - n - hexyloxy - benzoic acid , to react with terpenol , borneol , cinchonidine , and quinine respectively to obtain compound t1 , b1 , c1 , and q1 via esterifications , referring to the reactions as shown below . in another aspect of the present invention , the method of preparing liquid crystal compounds represented by formula ( i ) comprises providing an organic acid , such as 4 - n - propyl - cyclohexanecarboxylic acid , to react with terpenol , borneol , cinchonidine , and quinine respectively to obtain compound t2 , b2 , c2 , and q2 via esterifications , referring to the reactions as shown below . in yet another aspect of the present invention , the method of preparing liquid crystal compounds represented by formula ( i ) comprises providing an organic acid , such as 4 ′- decyloxy - biphenyl - 4 - carboxylic acid to react with terpenol , borneol , cinchonidine , and quinine respectively to obtain compound t3 , b3 , c3 , and q3 via esterifications , referring to the reactions as shown 10 below . in still another aspect of the present invention , the method of preparing liquid crystal compounds represented by formula ( ii ) comprises providing an organic acid , such as cyclohexane - 1 , 4 - dicarboxylic acid to react with terpenol , and borneol respectively to obtain compound t4 and b4 via esterifications , referring to the reactions as shown below . in the present invention , the liquid crystal composition comprises a component of at least one liquid crystal compound represented by formula ( i ) or formula ( ii ), preferably compound t1 , t2 , t3 , b1 , b2 , b3 , c1 , c2 , c3 , q1 , q2 , q3 , t4 or b4 . the following embodiments are intended to illustrate the invention more fully without limiting their scope , since numerous modifications and variations will be apparent to those skilled in this art . the method of preparing liquid crystal compounds represented by formula ( i ) and formula ( ii ) are described in detail through examples 1 to 14 . the helical pitch ( p ) of liquid crystal compounds can be found by testing as follows . first , a liquid crystal compound according to the present invention ( 1 % by weight ) was added to a liquid crystal composition “ zli - 1132 ” ( a commercially available product manufactured by merck company ) to prepare a chiral nematic liquid crystal composition . this composition was filled in a wedge type cell subjected to a parallel treatment , followed by observing the resulting cell under a polarizing microscope , such as olympus mx50 polarizing microscope . as a result , the resulting helical pitch was observed as follows . the helical twisting power can be calculated from the helical pitch ( p ) of liquid crystal compound using the formula htp =( p × c ) − 1 . in a nitrogen atmosphere , a mixture of 1 . 0 g of terpenol , 1 . 46 g of 4 - n - hexyloxy - benzoic acid , 1 . 36 g of n , n &# 39 ;- dicyclohexyl carbodimide ( dcc ), 0 . 80 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane was added into a round - bottom flask at room temperature . after mixing completely for 60 minutes , the resulting mixture was heated to reflux for 24 hours with stirring . after cooling , the resulting mixture was subjected to extraction with water and ch 2 cl 2 , dried over anhydrous mgso 4 , filtered , and condensed . the residue was subjected to purification by column chromatography from a mixed solvent ( ea : n - hexane = 1 : 3 ), giving [( 4s )- 4 - isopropenyl - 1 - cyclohexenyl ] methyl 4 -( hexyloxy ) benzoate , a liquid crystal compound according to the present invention , as a white solid having a melting point about 45 - 46 ° c . in a 38 % yield . the compound exhibited a specific rotation [ α ] of − 81 . 27 and a helical pitch p of 84 . 6 μm , and helical twisting power ( htp ) value thereof is 1 . 18 μm − 1 . example 2 was performed as example 1 except for substitution of 1 . 0 g of terpenol , 1 . 3 g of 4 - n - propyl - cyclohexane - carboxylic acid , 1 . 61 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 1 . 0 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to purification by column chromatography from a mixed solvent ( ea : n - hexane = 1 : 20 ), giving [( 4s )- 4 - isopropenyl - 1 - cyclohexenyl ] methyl 4 -( hexyloxy ) benzoate , as a white solid in a 32 . 4 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of − 52 . 4 and a helical pitch p of 80 . 9 μm , with helical twisting power of 1 . 24 μm − 1 . example 3 was performed as example 1 except for substitution of 0 . 47 g of terpenol , 1 . 0 g of 4 ′- decyloxy - biphenyl - 4 - carboxylic acid , 0 . 71 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 42 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from methanol / hexane , giving [( 4s )- 4 - isopropenyl - 1 - cyclohexenyl ]- 4 -( decyloxy )- biphenyl benzoate , as a white solid having a melting point about 45 - 46 ° c . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of − 31 . 03 and a helical pitch p of 75 . 7 μm , with helical twisting power of 1 . 32 μm − 1 . example 4 was performed as example 1 except for substitution of 0 . 97 g of terpenol , 0 . 5 g of cyclohexane - 1 , 4 - dicarboxylic acid , 1 . 38 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 82 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to purification by column chromatography from a mixed solvent ( ea : n - hexane = 1 : 5 ), giving di [( 4s )- 4 - isopropenyl - 1 - cyclohexenyl ] 1 , 4 - cyclohexanedicarboxylate , as a white solid having a melting point about 89 ° c . in a 18 . 11 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of − 66 . 1 and a helical pitch p of 50 . 5 μm , with helical twisting power of 1 . 98 μm − 1 . example 5 was performed as example 1 except for substitution of 0 . 76 g of l - borneol , 1 . 0 g of 4 - n - hexyloxy - benzoic acid , 1 . 11 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 68 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to purification by column chromatography from a mixed solvent ( ea : n - hexane = 1 : 4 ), giving ( 1s , 2r , 4s )- 4 , 7 , 7 - trimethylbicyclo [ 2 . 2 . 1 ] hept - 2 - yl - 4 -( hexyloxy ) benzoate , as a white solid in a 74 . 53 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of − 25 . 7 and a helical pitch p of 8 . 2 μm , with helical twisting power of 12 . 23 μm − 1 . example 6 was performed as example 1 except for substitution of 1 . 0 g of l - borneol , 1 . 28 g of 4 - n - propyl - cyclohexanecarboxylic acid , 1 . 61 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 95 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from a mixed solvent ( ch 2 cl 2 : methanol = 1 : 3 ), giving ( 1s , 2r , 4s )- 4 , 7 , 7 - trimethylbicyclo [ 2 . 2 . 1 ] hept - 2 - yl 4 - propyl - 1 - cyclohexanecarboxylate , as a white solid in a 21 . 36 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of − 22 . 82 and a helical pitch p of 11 . 8 μm , with helical twisting power of 8 . 45 μm − 1 . example 7 was performed as example 1 except for substitution of 1 . 0 g of l - borneol , 1 . 28 g of 4 ′- decyloxy - biphenyl - 4 - carboxylic acid , 1 . 61 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 95 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from a mixed solvent ( ch 2 cl 2 : methanol = 1 : 3 ), giving ( 1s , 2r , 4s )- 4 , 7 , 7 - trimethylbicyclo [ 2 . 2 . 1 ] hept - 2 - yl 4 -( decyloxy )- biphenylbenzoate , as a white solid in a 48 . 32 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of − 18 . 94 and a helical pitch p of 10 . 2 μm , with helical twisting power of 9 . 85 μm − 1 . example 8 was performed as example 1 except for substitution of 0 . 99 g of l - borneol , 0 . 5 g of cyclohexane - 1 , 4 - dicarboxylic acid , 1 . 38 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 82 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from a mixed solvent ( ch 2 cl 2 : methanol = 4 : 7 ), giving di [( 1s , 2r , 4s )- 4 , 7 , 7 - trimethylbicyclo [ 2 . 2 . 1 ] hept - 2 - yl ] 1 , 4 - cyclohexanedicarboxylate , as a white solid having a melting point about 77 ° c . in a 82 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of − 21 . 33 and a helical pitch p of 13 . 5 μm , with helical twisting power of 7 . 39 μm − 1 . example 9 was performed as example 1 except for substitution of 2 . 91 g of cinchonidine , 2 . 0 g of 4 - n - hexyloxy - benzoic acid , 2 . 33 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 1 . 32 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from methanol , giving ( r )- 1 -( 4 - quinolyl )- 1 -[( 2s , 4s , 5r )- 5 - vinyl - l - azabicyclo [ 2 . 2 . 2 ] oct - 2 - yl ] methyl 4 -( hexyloxy ) benzoate , as a white solid having a melting point about 70 ° c . in a 72 . 3 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of + 57 . 59 and a helical pitch p of 5 . 1 μm , with helical twisting power of 19 . 7 μm − 1 . example 10 was performed as example 1 except for substitution of 2 . 7 g of cinchonidine , 1 . 5 g of 4 - n - propyl - cyclohexanecarboxylic acid , 2 . 1 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 1 . 2 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from methanol , giving ( r )- 1 -( 4 - quinolyl )- 1 -[( 2s , 4s , 5r )- 5 - vinyl - 1 - azabicyclo [ 2 . 2 . 2 ] oct - 2 - yl ] methyl 4 - propyl - 1 - cyclohexanecarboxylate , as a white solid with a chemical purity 91 . 31 %. the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of + 5 . 52 and a helical pitch p of 3 . 1 μm , with helical twisting power of 32 . 2 μm − 1 . example 11 was performed as example 1 except for substitution of 1 . 83 g of cinchonidine , 2 . 0 g of 4 ′- decyloxy - biphenyl - 4 - carboxylic acid , 1 . 4 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 83 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from methanol , giving ( r )- 1 -( 4 - quinolyl )- 1 -[( 2s , 4s , 5r )- 5 - vinyl - 1 - azabicyclo [ 2 . 2 . 2 ] oct - 2 - yl ] methyl 4 -( decyloxy ) biphenylbenzoate , as a white solid having a melting point about 81 ° c . in a 29 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of + 105 . 96 and a helical pitch p of 2 . 8 μm , with helical twisting power of 35 . 5 μm − 1 . example 12 was performed as example 1 except for substitution of 1 . 61 g of quinine , 1 . 0 g of 4 - n - hexyloxy - benzoic acid , 1 . 11 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 66 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to purification by column chromatography from ethyl acetate , giving ( r )- 1 -( 6 - methoxy - 4 - quinolyl )- 1 -[( 2s , 4s , 5r )- 5 - vinyl - 1 - azabicyclo [ 2 . 2 . 2 ] oct - 2 - yl ] methyl - 4 -( hexyloxy )- benzoate , as a white solid with a chemical purity 90 . 1 % in a 19 . 1 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of + 12 . 07 and a helical pitch p of 4 . 5 μm , with helical twisting power of 22 . 2 μm − 1 . example 13 was performed as example 1 except for substitution of 2 . 97 g of quinine , 1 . 5 g of 4 - n - propyl - cyclohexanecarboxylic acid , 2 . 1 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 1 . 22 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from a mixed solvent ( ch 2 cl 2 : methanol = 1 : 3 ), giving ( r )- 1 -( 6 -( r )- 1 -( 6 - methoxy - 4 - quinolyl )- 1 -[( 2s , 4s , 5r )- 5 - vinyl - 1 - azabicyclo [ 2 . 2 . 2 ] oct - 2 - yl ] methyl - 4 - propyl - 1 - cyclohexanecarboxylate , as a white solid with a chemical purity 97 . 2 % in a 10 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of + 9 . 27 and a helical pitch p of 2 . 82 μm , with helical twisting power of 35 . 46 μm − 1 . example 14 was performed as example 1 except for substitution of 1 . 0 g of quinine , 1 . 0 g of 4 ′- decyloxy - biphenyl - 4 - carboxylic acid , 0 . 7 g of n , n ′- dicyclohexyl carbodimide ( dcc ), 0 . 41 g of n , n -( dimethyl amino )- pyridine ( dmap ) and 80 ml of dichloromethane into a round - bottom flask . after filtering and condensing , the residue was subjected to recrystallization from a mixed solvent ( ch 2 cl 2 : methanol = 1 : 3 ), giving ( r )- 1 -( 6 -( r )- 1 -( 6 - 5 methoxy - 4 - quinolyl )- 1 -[( 2s , 4s , 5r )- 5 - vinyl - 1 - azabicyclo [ 2 . 2 . 2 ] oct - 2 - yl ] methyl 4 - propyl - 1 - cyclohexanecarboxylate , as a white solid in a 35 . 8 % yield . the optical properties of the resulting compound were tested as in example 1 . the compound exhibited a specific rotation [ α ] of + 15 . 76 and a helical pitch p of 1 . 7 μm , with helical twisting power of 59 . 1 μm − 1 . the results of optical properties for liquid crystal compounds as described in examples 1 to 14 are shown in table 1 . preparation of liquid crystal composition the liquid crystal compound with the htp value more than 15 μm − 1 as described above , such as compound q3 , is provided to process solubility tests and mix with various nematic liquid crystals to prepare liquid crystal compositions with a peak reflected wavelength about 560 nm . according to the present invention , suitable nematic liquid crystal can be zli - 5100 - 100 , zli - 5200 - 100 , zli - 5400 - 100 , mlc - 6657 - 100 , mlc - 6700 - 100 ( trademark , liquid crystal product sold by e . merck , germany ), or rpd - 88873 ( trademark , liquid crystal product sold by dic ). the processes and results are described in detail through examples 15 to 20 . the liquid crystal composition ( a ) with a selectively reflected wavelength 560 nm was obtained by uniformly mixing 90 parts by weight of a commercially available nematic liquid crystal , zli - 5100 - 100 ( available from e . merck , germany ) and 10 parts by weight of the compound q3 of the present invention prepared in example 14 . afterward , the liquid crystal composition ( a ) filled a pda having a 2 - inch diagonal display ( manufactured by picvue electronics , ltd ) to distinguish the exact relationship between reflectivity and operational voltage at a measuring wavelength of 560 nm . the result is shown in fig1 . the liquid crystal composition ( b ) with a selectively reflected wavelength 560 nm was obtained by uniformly mixing 86 . 5 parts by weight of a commercially available nematic liquid crystal , zli - 5200 - 100 ( available from e . merck , germany ) and 13 . 5 parts by weight of the compound q3 of the present invention prepared in example 14 . the relationship between reflectivity and operational voltage of the resulting composition was distinguished as in example 15 , and the result is shown in fig2 . the liquid crystal composition ( c ) with a selectively reflected wavelength 560 nm was obtained by uniformly mixing 88 parts by weight of a commercially available nematic liquid crystal , zli - 5400 - 100 ( available from e . merck , germany ) and 12 parts by weight of the compound q3 of the present invention prepared in example 14 . the relationship between reflectivity and operational voltage of the resulting composition was distinguished as in example 15 , and the result is shown in fig3 . the liquid crystal composition ( d ) with a selectively reflected wavelength 560 nm was obtained by uniformly mixing 87 . 78 parts by weight of a commercially available nematic liquid crystal , mlc - 6657 - 100 ( available from e . merck , germany ) and 12 . 22 parts by weight of the compound q3 of the present invention prepared in example 14 . the relationship between reflectivity and operational voltage of the resulting composition was distinguished as in example 15 , and the result is shown in fig4 . the liquid crystal composition ( e ) with a selectively reflected wavelength 560 nm was obtained by uniformly mixing 87 . 78 parts by weight of a commercially available nematic liquid crystal , mlc - 6657 - 100 ( available from e . merck , germany ) and 11 . 38 parts by weight of the compound q3 of the present invention prepared in example 14 . the relationship between reflectivity and operational voltage of the resulting composition was distinguished as in example 15 , and the result is shown in fig5 . the liquid crystal composition ( f ) with a selectively reflected wavelength 560 nm was obtained by uniformly mixing 88 parts by weight of a commercially available nematic liquid crystal , rpd - 88873 ( available from dic ) and 12 parts by weight of the compound q3 of the present invention prepared in example 14 . the relationship between reflectivity and operational voltage of the resulting composition was distinguished as in example 15 , and the result is shown in fig6 . the respective relative proportions of liquid crystal compound q3 of the present invention prepared in example 14 and various nematic liquid crystal as described in examples 15 to 20 are shown in table 2 . the liquid crystal compounds according to the present invention have high htp value resulting from the natural alcoholic structure with high specific rotation and numerous chiral centers thereof . particularly , the htp values of liquid crystal compounds having the structure of cinchonidine or quinine , such as compound c3 and q3 , exceed that of conventional liquid crystal compounds . as well , core structures similar to those of liquid crystal are designed to join in the liquid crystal compounds according to the present invention . as a result , miscibility between the liquid crystal compounds and nematic liquid crystal is significantly improved . for that matter , there is still excellent miscibility when the liquid crystal compounds are added into a liquid crystal composition over 15wt %. another advantage of the present invention is that the raw material , such as terpenol , borneol , cinchonidine , or quinine , of the liquid crystal compounds is generally available , since these natural alcohols resulting from optical activity , purity , and high htp value thereof are used frequently industrially , presenting readily available large quantities . compared to conventional liquid crystal compounds , manufacturing costs can be substantially reduced . the method of preparing liquid crystal compounds according to the present invention comprises providing an organic acid compound having similar core structure to liquid crystal to react with a natural alcohol with optical activity having multi - ring structure to undergo esterification by easy synthesis step . hence , the method according to the present invention is suitable for mass production of liquid crystal compounds . increasingly popular portable and outdoor - use reflective displays demand enhanced temperature dependance and resistance to light . the liquid crystal composition according to the present invention provides this high resistance to light and low temperature dependance , and , for this reason , it is very suitable for use in reflective display . liquid crystal compounds having the structure of cinchonidine or quinine , such as compound c1 c2 c3 q1 q2 and q3 as described above , can be used to form cholesteric liquid crystal reflective polarizer or color filter by polymerization with reactive type liquid crystal . conventional liquid crystal compounds with lower htp value must be used in increased amounts mixing with nematic liquid crystal to conform to lcd requirements . on the contrary , the doping amount of liquid crystal compounds according to the present invention used in the liquid crystal composition for lcd , such as tn - lcd , stn - lcd , and tft - lcd , can be decreased resulting from the high htp value thereof . for this reason , the manufacturing cost of the liquid crystal composition is reduced . while the invention has been described by way of example and in terms of the preferred embodiments , it is to be understood that the invention is not limited to the disclosed embodiments . to the contrary , it is intended to cover various modifications and similar arrangements ( as would be apparent to those skilled in the art ). therefore , the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements .