Patent ID: 8076563

Claim:
A keyboard device comprising: a keyboard chassis; a key provided on the keyboard chassis in a manner to be rotatable in a vertical direction; a hammer member for applying an action load to the key by rotating to be displaced in response to depression of the key; and an elastic section provided in at least one of either the hammer member or the key, which is elastically deformed in response to the depression of the key; wherein the keyboard device is configured such that, when considered as a mechanical oscillation system model where L represents a distance in a horizontal direction from a rotation support of the hammer member to a contact point at which the key comes into contact with the hammer member, I represents a moment of inertia around the rotation support of the hammer member, and K represents an elastic modulus in a vertical direction of the elastic section in at least one of either the hammer member or the key, in an initial state in which the key has not been depressed, a relationship of the distance L in the horizontal direction, the moment of inertia I, and the elastic modulus K is set to (2/π) 2 ·K·10 −4 ≦(I/L 2 )≦4·(2/π) 2 ·K·10 −4 , and a timing at which the action load applied to the key by the hammer member in response to the depression of the key reaches a maximum is delayed by a predetermined amount of time.