Scanning optical device
AssigneeCanon Kabushiki Kaisha
InventorKoji Toyoda
Life of this patent
Estimating the term…
Abstract
In a scanning optical device, a light beam emitted from a light source is deflected by a deflector to reach as a light spot a surface to be scanned through a scanning optical system. At least one of the optical surfaces of optical elements constituting the scanning optical system is provided with a diffraction grating having a power based on a change in pitch. The power of the diffraction grating asymmetrically changes within a plane of the optical element surface, on which the diffraction grating is formed, without any symmetrical axis, in at least one of a main scanning direction and sub-scanning direction.
Claims20
A scanning optical device comprising:
- light source means;
- deflection means for deflecting a light beam emitted from said light source means;
- and
- scanning optical means for forming a spot of the light beam deflected by said deflection means on a scanned surface,
- wherein a diffraction grating having a power based on a change in pitch is formed on at least one of optical surfaces of optical elements constituting said scanning optical means, and the power of said diffraction grating asymmetrically changes within a plane of the optical element surface, on which said diffraction grating is formed, without any symmetrical axis, in at least one of a main scanning direction and sub-scanning direction.
A scanning optical device comprising:
- light source means;
- deflection means for deflecting a light beam emitted from said light source means;
- and
- scanning optical means for forming a spot of the light beam deflected by said deflection means on a scanned surface,
- wherein a diffraction grating is formed on at least one of optical surfaces of optical elements constituting said scanning optical means, a pitch of said diffraction grating changes without any symmetrical axis in at least one of a main scanning direction and sub-scanning direction, and
- at least one of the optical surfaces of said optical elements constituting said scanning optical means is asymmetrically shaped from an on-axis position to an off-axis position in at least one of the main scanning direction and sub-scanning direction.
Dependencies are inferred from the claim text.