Abstract: A scanning device for scanning a flat scanned surface by means of a rotating or rotatively vibrating deflector. The scanning device is provided with a rotational asymmetric image forming optical system disposed between the deflector and the scanned surface for forming an image of the scanned surface at a substantially equal distance from the deflecting surface of the deflector in the plane defined by the path of movement of the normal to the deflecting surface of the deflector in accordance with the rotation thereof.

Abstract: A two-dimensional scanning optical system comprising a deflector capable of two-dimensional deflection of a light beam in two mutually orthogonal directions, an imaging lens system provided with a predetermined distortion characteristic and capable of focusing the light beam deflected by said deflector onto a plane to be scanned, and a light source for introducing said light beam into said deflector in a direction parallel to the optical axis of said imaging lens system, thereby achieving a scanning on said plane with substantially linear scan lines.

Abstract: A scanning image forming optical system disposed in a scanning optical system includes a single lens having the both surfaces thereof divided into a light-transmitting area and a light-reflecting area, whereby the scanning optical system is compact and various aberrations in the image forming optical system is improved.

Abstract: Two-dimensional scanning apparatus scans a stationary two-dimensional surface with a first deflector and a second deflector which deflects a light beam in a direction perpendicular to the deflecting direction of said first deflector. An afocal optical system is provided between said first and second deflectors, while an imaging lens system is provided between said second deflector and the scanning surface. Said first deflector, afocal optical system and imaging lens system cooperate to displace the light beam at a constant speed in a principal scanning direction on the scanning surface, while said second deflector and imaging lens system cooperate to displace the light beam at a constant speed in an auxiliary scanning direction on said surface.

Abstract: A light beam scanning device provided with a light source section to emit a scanning beam, a deflector to deflect the light beam from the light source section at a constant angular speed in a predetermined direction, and a lens system to focus the scanning beam deflected by the deflector on a scanning surface, wherein the lens system consists of two single lenses which are mutually positioned at a finite distance, the single lens at the side of the deflector has a negative refractive power, the single lens at the side of the scanning surface has a positive refractive power, and the scanning beam moves at a constant speed on the surface to be scanned due to the lens system having the f-.theta. characteristics.