Authentiation allowing for lower case password

I have created a regex that requires the user create a pw with 6-15 charaters including 1 upper case and 1 number. The login page is allowing me to be authenticated when I type in all lowercase. Why is this happening?  I'm using a stored procedure:
Protected Sub Login1_Authenticate(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.AuthenticateEventArgs) Handles Login1.Authenticate         If Authentication(Login1.UserName, Login1.Password) Then             e.Authenticated = True             ' Store your authentication mode in session variable             Session("Check") = True             FormsAuthentication.RedirectFromLoginPage(Login1.UserName, Login1.RememberMeSet)
Go to the complete details ...