From polymorph, under transmutation (where all the important stuff on beast shape is, 100 pages away from it....)
Items that provide constant bonuses and do not need to be activated continue to function while melded in this way (with the exception of armor and shield bonuses, which cease to function). Items that require activation cannot be used while you maintain that form.
An iron band, this simple ring generates a shield-sized (and shield-shaped) wall of force that stays with the ring and can be wielded by the wearer as if it were a heavy shield (+2 AC). This special creation has no armor check penalty or arcane spell failure chance since it is weightless and encumbrance-free. It can be activated and deactivated at will as a free action.
I would say no, but i agree its a little iffy. While i can see the argument that you can activate the ring and let the shield stay out 24/7, what is really standing out at me is the phrase "Items that provide constant bonuses AND do not need to be activated continue to function while melded in this way" The ring of force shield provides a constant bonus, but it does need to be activated, making it IMHO unable to be used while wild shaped. It will shut off. If items that provide constant bonuses and do not need to be activated continue to function, that implies that items that fall into either or both categories do not continue to function. The ring is such an item and ceases to function because it requires activation.
Can this ring be activated and used during wildshape? It is at-will to activate, requiring no interaction with the ring itself (unlike boot items, sadly). Wanting to use for a PFS druid, so no house rulings
Page 212 = Polymorph
"""...Items that provide constant bonuses and do not need to be activated continue to function while melded in this way (with the exception of armor bonuses, which cease to function). Items that require activation cannot be used while you maintain that form..."""
You can not activate the ring while wildshaped.