Abstract: There is provided an optical system of an optical pick-up for a plurality of types of optical discs, which is provided with a plurality of light sources that support the plurality of types of optical discs, a first coupling lens that is used at least for the first optical disc, and an objective lens that is used for the plurality of types of optical discs. A beam for the first optical disc emitted by the plurality of light sources passes through the first coupling lens and is incident on the objective lens as a diverging beam, the diverging beam being given spherical aberration by the coupling lens. When the objective lens shift occurs, a coma component relating to the spherical aberration of the diverging beam which is shifted with respect to the objective lens due to the shift of the objective lens is canceled by a coma generated by the objective lens and the cover layer of the first optical disc.

Abstract: A scanning optical system includes a polygonal mirror that deflects the even number of beams, which are incident thereon along optical paths arranged symmetrically with respect to a plane perpendicular to a rotation axis thereof. An imaging optical system for converging the beams includes lenses for converging the beam, in an auxiliary scanning direction, respectively. The lenses have the same shapes, and are arranged symmetrically with respect to the plane. The orientation of the lenses on one side of the plane is oriented oppositely, in the auxiliary scanning direction, to the other lenses located on the other side of the plane.

Abstract: There is provided a scanning optical system including a collimator lens being placed on an optical path between a light source and a deflecting system. At least one of a front surface and a rear surface of the collimator lens includes a central area through which part of the laser beam in the vicinity of a central axis of the laser beam passes, at least one first outer area having an effect on the laser beam so that the laser beam after passing through said at least one first outer area is given a first phase difference not including a phase difference of zero, and at least one second outer area having an effect on the laser beam so that the laser beam after passing through said at least one second outer area is given a second phase difference being different from the first phase difference and including a phase difference of zero.

Abstract: A scanning optical system that emits a plurality of beams to a plurality of surfaces to be scanned, respectively. The scanning optical system includes a light source and a polygonal mirror. The plurality of beams incident on the polygonal mirror are inclined with respect each other in an auxiliary scanning direction. The scanning optical system further includes an imaging optical system that converges the deflected beams on the plurality of surfaces, respectively. The imaging optical system includes a front lens group and a plurality of rear lens groups. All the beams are incident on the front lens group, and then incident on the respective rear lens groups. Each of the plurality of rear lens groups has a shape which is designed in accordance with an angle of a beam incident thereon with respect to an optical axis of the front lens group.

Abstract: There is provided a scanning optical system, which is provided with a deflector that deflects the plurality of beams, and an imaging optical system that converges the plurality of beams deflected by the deflector to form a plurality of beam spots on surfaces to be scanned, respectively. The imaging optical system has at least one lens whose position is changeable in a plane including an optical reference axis thereof and parallel with the main scanning direction. In this configuration, the imaging optical system satisfies a condition: 0.05<|f/fL|<0.5, where, f represents a focal length of the imaging optical system in the main scanning direction, and fL represents a focal length of the at least one lens in the main scanning direction.

Abstract: A scanning lens which converges a beam deflected by a deflector on a surface to be scanned, is provided with at least one refractive lens, and a diffractive lens structure formed on at least one surface of the at least one refractive lens. The scanning lens is configured to satisfy the following condition: 9.0<fd/f<17.0, where fd is a focal length of the at least one diffractive lens structure, f is a focal length of the scanning lens as a whole including the at least one diffractive lens structure and the at least one refractive lens. Further, the scanning lens is configured so that lateral chromatic aberration is compensated for both of a first wavelength and a second wavelength which is different from the first wavelength.

Abstract: An objective lens for an optical pickup has a single lens element. One surface of the objective lens is divided into a central area and a peripheral area, and a step providing a level difference along a direction of the optical axis is formed at a boundary therebetween. The step provides a phase shift between light passing through the central area and the peripheral area. The level difference is formed such that a thickness on the peripheral area side is greater than a thickness on the central area side at the boundary.

Abstract: An objective lens for an optical pickup is configured such that, when a light beam having a wavelength corresponding to the optical disc requiring the higher NA is converged on the optical disc requiring the higher NA at the higher NA, the phase of light flux passed through the peripheral area is substantially the same as that passed through the central area. When a light beam having a wavelength corresponding to the optical disc requiring the lower NA is converged on the optical disc requiring the lower NA at the lower NA, the phase of light flux passed through a first annular region included in the peripheral area is different from that passed through the central area, and the phase of light flux passed through a second annular region, which is outside the first region, is substantially the same as that passed through the central area.

Abstract: A scanning optical system includes first and a second lens elements, at least one of which is a plastic lens element. Each surface of the plastic lens element is an aspherical surface that is configured such that a shape in a main scanning plane is defined as a function of a distance, in the main scanning direction, from a surface reference axis thereof, and that a curvature in an auxiliary scanning plane which is perpendicular to the main scanning plane is defined as another function of a distance, in the main scanning direction, from the surface reference axis. At least one of the two surfaces of the plastic lens element are arranged such that the surface reference axis thereof is decentered from an axis of the beam in the auxiliary scanning direction.

Abstract: There is provided a scanning optical system, which is provided with a deflector that deflects the plurality of beams, and an imaging optical system that converges the plurality of beams deflected by the deflector to form a plurality of beam spots on surfaces to be scanned, respectively. The imaging optical system has at least one lens whose position is changeable in a plane including an optical reference axis thereof and parallel with the main scanning direction. In this configuration, the imaging optical system satisfies a condition: 0.05<|f/fL|<0.5, where, f represents a focal length of the imaging optical system in the main scanning direction, and fL represents a focal length of the at least one lens in the main scanning direction.

Abstract: A scanning optical system includes a polygonal mirror that deflects the even number of beams, which are incident thereon along optical paths arranged symmetrically with respect to a plane perpendicular to a rotation axis thereof. An imaging optical system for converging the beams includes lenses for converging the beam, in an auxiliary scanning direction, respectively. The lenses have the same shapes, and are arranged symmetrically with respect to the plane. The orientation of the lenses on one side of the plane is oriented oppositely, in the auxiliary scanning direction, to the other lenses located on the other side of the plane.

Abstract: A scanning optical system that emits a plurality of beams to a plurality of surfaces to be scanned, respectively. The scanning optical system includes a light source and a polygonal mirror. The plurality of beams incident on the polygonal mirror are inclined with respect each other in an auxiliary scanning direction. The scanning optical system further includes an imaging optical system that converges the deflected beams on the plurality of surfaces, respectively. The imaging optical system includes a front lens group and a plurality of rear lens groups. All the beams are incident on the front lens group, and then incident on the respective rear lens groups. Each of the plurality of rear lens groups has a shape which is designed in accordance with an angle of a beam incident thereon with respect to an optical axis of the front lens group.

Abstract: A scanning optical system is configured to include a light source, an anamorphic optical element, a polygonal mirror, and an imaging optical system. The imaging optical system has a scanning lens including a first lens provided on a polygonal mirror side and a second lens provided on a surface side, and a compensation lens provided on the surface side with respect to the scanning lens, the compensation lens compensating for curvature of field. The scanning lens includes at least one convex surface that has a toric surface having a stronger power in the auxiliary scanning direction than in the main scanning direction. One surface of the compensation lens has an anamorphic aspherical surface, which is a surface whose radius of curvature in the auxiliary scanning direction at a point spaced from the optical axis thereof is determined independently from a cross-sectional shape thereof along the main scanning direction.

Abstract: A scanning optical system includes a light source, an anamorphic optical element, a polygonal mirror, and an imaging optical system that converges the beam(s) on a surface to be scanned. The imaging optical system has a scanning lens, and a compensation lens provided on the surface side for compensating for curvature of field. All the surfaces of the scanning lens are rotationally symmetrical, and the compensation lens has an aspherical surface. A cross section of the aspherical surface in the auxiliary scanning direction is asymmetrical with respect to the optical axis thereof, and a SAG amount defining the aspherical surface is expressed by a two-dimensional polynomial.

Abstract: A three-group zoom lens has, from an object side, a first group lens having a positive power, a second group lens having a negative power and a third group lens consisting of a positive lens. The second lens group includes an aperture stop. When a distance to be focused is infinity, only the first lens group and the second lens group move for zooming. At least one positive lens included in the zoom lens has an aspherical surface whose positive power is greater at a portion farther from an optical axis thereof. The zoom lens satisfies the following conditions: −0.85<f2/f1<−0.65 and 5.0<f3/fw<8.0  where, fw represents a focal length when positioned at a wide-extremity, and f1, f2 and f3 respectively represent focal lengths of the first, second and third lens groups.

Abstract: A scanning lens which converges a beam deflected by a deflector on a surface to be scanned, is provided with at least one refractive lens, and a diffractive lens structure formed on at least one surface of the at least one refractive lens.

Abstract: The optical system of the microscope includes a close-up optical system that faces an object, a pair of imaging optical systems that take object light rays passing through regions of the close-up optical system, and an illuminating optical system that guides illumination light emitted from a light source to illuminate the object. Each lens included in the close-up optical system has a semicircular shape in which one side is cut out. The close-up optical system is held in a first lens barrel, and the illuminating optical system is held in a second lens barrel. The second lens barrel is arranged in the cutout space of the close-up optical system inside the first lens barrel. A light shielding member is attached to the second lens barrel to prevent a leak of the illumination light through grooves formed on the second lens barrel.

Abstract: Disclosed is a manufacturing method of a complex lens for a tandem scanning optical system that includes a step for preparing molding dies for forming a cavity to form the complex lens as a single-piece element, and a step for injecting lens material into the cavity. The molding dies include a pair of single-piece mirror surface cores that form a plurality of lens surfaces of the complex lens at an incident side and a plurality of lens surfaces at an exit side, respectively. The complex lens has a plurality of stacked lens portions and the lens portions converging a plurality of light beams, which are modulated independently and deflected by a deflector, onto a surface to be scanned, respectively, for forming a plurality of scanning lines at the same time.

Abstract: Disclosed is a scanning optical system that includes a laser source for emitting a laser beam, a scanning deflector that deflects the laser beam, an imaging optical system that converges the scanning laser beam onto an object surface, first and second mirrors that bend the optical path of the scanning laser beam. The first and second mirrors are movable to adjust the optical path length between the deflector and the object surface for changing a width of the scanning range on the object surface. Since the optical path length is adjusted by moving the first and second mirror, which changes the width of the scanning range, correcting the size error of the printed image. When the size error of the printed image is detected, an operator moves the first and second mirrors to correct it.

Abstract: The stereoscopic microscope includes a common close-up optical system that faces an object, a pair of zoom optical systems that form a pair of primary image, a pair of field stops, a pair of relay optical systems that relay the primary images to form a pair of secondary images, an inter-axis distance reducing element, an image taking device and an illuminating optical system. The object light rays incident on the close-up optical system form the primary images having predetermined parallax at the field stops through the zoom optical systems. The inter-axis distance reducing element reduces the inter-axis distance of the right and left light rays. The primary images are re-imaged by the relay optical systems as the secondary images on the adjacent regions on the single image taking surface of the image taking device, respectively.