US Patent 11066038 Occupant protection system

An occupant protection system includes a seat disposed such that a rear surface of a seatback in a seat front-rear direction faces a wall portion of a vehicle cabin; an airbag provided in the wall portion or the seatback and configured to support the seatback by inflating and deploying between the wall portion and the seatback; and an inflator configured to generate gas to be supplied to the airbag in a case where a collision that causes an occupant seated in the seat to inertially move rearward in the seat front-rear direction is detected or predicted. The airbag has a vent hole through which the gas inside the airbag is discharged outside.