Patent ID: 7853381

Claim:
A vehicle occupant protection device comprising: a headrest configured to be movable forward with respect to a vehicle; a processor configured to determine whether a collision can be avoided; an actuator configured to receive collision information from the processor and to implement the forward movement of the headrest in a pre-crash stage before an object crashes into a backside of the vehicle, the pre-crash stage indicating that a crash cannot be avoided; and an electrical capacitance sensor disposed in the headrest and connected to the processor, and wherein the processor is configured to control an amount of the forward movement of the headrest during the pre-crash stage according to an electrical capacitance change gradient, which is derived from a change in a ratio of a detected electrical capacitance and a reference electrical capacitance with respect to a change in time, and wherein said detected electrical capacitance is detected by the electrical capacitance sensor when the headrest moves forward.