Patent ID: 8180215

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 to the X-axis that is a given axis of symmetry; 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 n ⁢ ⁢ m ⁡ ( 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; and a ratio between a first bending rigidity along the X-axis of at least the dust-screening member and vibrating member in the section orthogonal to the X-axis at the intersection of the X- and Y-axes, to a second bending rigidity along the Y-axis of at least the dust-screening member in the section orthogonal to the Y-axis at the intersection is 0.4 or more, but less than 1.0, the Y-axis being orthogonal to the X-axis in a virtual rectangle which has the same area as the surface of the dust-screening member, and which has long sides including the one side of the dust-screening member.