examples 2 1 to 2 3 the results are also shown in table 2 in 495 0 g of perfluorohexane was dissolved 5 0 g of the perfluoropolyether modified aminosilane synthesized in each of synthetic examples 1 to 3 the coating solution was spin coated onto a glass lens the coating was allowed to stand for 2 hours in an atmosphere at 40 u00b0 c and humidity 85 whereby the coating cured the surface was wiped off with dry fabric completing the cured coating this test specimen was examined by the following tests using a contact angle meter model a3 kyowa kaimen kagaku k k the contact angle of the coated lens with water was measured as the rating of water repellency the forefinger was pressed against the coated lens for 5 seconds leaving a fingerprint the lens was visually examined whether the fingerprint was definite or obscure it was also examined how the fingerprint was wiped off with dry fabric the evaluation was made according to the following criterion the rating was an average of a 5 member panel a coating solution was prepared and examined as in examples 3 1 to 3 3 except that the fluoroaminosilane synthesized in synthetic example 4 was used instead of the inventive aminosilane the results are also shown in table 3 a coating solution was prepared and examined as in examples 3 1 to 3 3 except that c 8 f 17 ch 2 ch 2 si och 3 3 was used instead of the inventive aminosilane the results are also shown in table 3 without applying the coating solution the glass lens was examined as in examples 3 1 to.