User defined types

 Hello:
 I have a user define type called VALID_TIME. It is declared as follows:
 CREATE TYPE VALID_TIME AS (t_s TIMESTAMP, t_e TIMESTAMP);
 Once I have used this in a table declaration, is it possible to extract
parts of it, for example to only read t_s or t_e? If so, how do I do this?
 Thank you. -Reza