US patent 5938197 shows that it is expired due to non-payment (according to the search here: http://portal.uspto.gov/pair/PublicPair ).
This patent has several children/continuations.
Does the fact that the parent has expired due to non-payment automatically mean that the children have expired as well? They do not all show expired when I search for them, but I am not sure to what extent a continuation is connected to it's parent patent.
As an example of what is causing my confusion, here is a continuation which says it is still a patented case (rather than saying expired due to non-payment): 6,123,332
However, there is a continuation of THAT patent which is expired due to non-payment: 6,318,720
So 6,318,720 (expired) is a continuation of 6,123,332 (not expired??), which is a continuation of 5938197 (expired).
Another example: d455462 does not say it is expired. It is a division of D436635 which does not say it is expired and is a continuation of 5,938,197 which is the original one mentioned expired due to non-payment.