Hi
Here is the limitation with display type of field you can only select one type either OVS or Link.
But As a work around you can add two field bind with same BO model field.
Make one as OVS and other as Link, And set the Visible property of each field.
when you select edit mode then set the property of OVS as Visible true(in calculation Rule).
and when UI is in display mode hide the OVS and set the visible property of field type link as visible in calculation rule.
Regards
Sunil