Patent ID: 8243184

Claim:
A vibrating device comprising: a dust-screening member shaped like a plate as a whole, having front and back surfaces and having a light-transmitting region for transmitting light between the front surface and the back surface; a support member configured to support the dust-screening member, thereby to render the back surface of the dust-screening member airtight; a vibrating member arranged at a circumference of the dust-screening member and shaped like a rectangle; and a vibration control unit configured to input an electrical signal to the vibrating member to generate, in the light-transmitting region, vibration forming a plurality of ridges of peaks defining a closed loop around a virtual intersection at which a virtual vibrational axis passing the half-length point of the vibrating member intersects with a virtual vibrational axis passing the half-length point of the dust-screening member, the vibration being one of vibration whose peak including the virtual intersection gradually increases in terms of amplitude as the amplitude of the peak approaches the virtual intersection, and becomes the largest in terms of amplitude at the virtual intersection, and vibration whose peak nearest the virtual intersection is the largest in terms of amplitude, wherein the dust-screening member and the vibrating member have the following relation: 1.2≦ Ts/Tg≦ 1.6 where Tg is the thickness of the thickness of the dust-screening member, and Ts is the thickness of the vibrating member.