Patent ID: 8253853

Claim:
A vibrating device comprising: a dust-screening member which is shaped like a plate as a whole and has at least one side that is symmetric with respect to a symmetry axis; a vibrating member secured to the dust-screening member and configured to produce, at the dust-screening member, vibration having a vibrational amplitude perpendicular to a surface of the dust-screening member; and a drive unit configured to drive the vibrating member to produce vibration Z(x, y) at the dust-screening member, the vibration being expressed as follows: Z ( x,y )= W mn ( x,y )·cos(γ)+ W nm ( x,y )·sin(γ) where Z(x, y) is vibration at a given point P(x, y) on the dust-screening member; m and n are positive integers including 0, indicating the order of natural vibration corresponding to a vibrational mode; W mn ⁡ ( x , y ) = sin ⁡ ( n ⁢ ⁢ π · x + π 2 ) · sin ⁡ ( m ⁢ ⁢ π · y + π 2 ) ; W nm ⁡ ( x , y ) = sin ⁡ ( m ⁢ ⁢ π · x + π 2 ) · sin ⁡ ( n ⁢ ⁢ π · y + π 2 ) ; ⁢ and γ is +π/4 or ranges from −π/8 to −π/4.