Abstract: A light beam scanning device scans a luminous flux irradiated from a light source and deflected by a deflector to a scanned surface through an optical system having a set of mirrors. A apparatus, such as the light beam scanning device, further includes a scanning line curve adjusting device to bend a first mirror of the set of mirrors so as to correct a curve in a scanning line on the scanned surface, and a scanning line tilt adjusting device to change orientation of a second mirror of the set of mirrors so as to correct a tilt in the scanning line on the scanned surface. The light beam scanning device may be provided in an image forming apparatus.

Abstract: An optical device includes: a light source that emits a light beam; a deflector that deflects the light beam in a main-scanning direction; and a scanning/image-forming optical system that includes a scanning lens that causes the light beam deflected by the deflector to converge to a scanned surface to form an image on the scanned surface. The scanning lens has refractive index gradient. At least one surface of the scanning lens is a tilt-decentered surface that has a tilt angle, which depends on a position in the main-scanning direction, in a sub-scanning direction. The tilt angle is set so as to compensate for variation, which results from the refractive index gradient, in direction of the light beam in the sub-scanning direction.

Abstract: A group 13 nitride crystal of hexagonal crystal including at least one or more metal atom selected from the group consisting of B, Al, Ga, In, and Tl, and a nitrogen atom, the group 13 nitride crystal comprises: a first region provided on the inner side of a cross section crossing a c-axis; a third region provided on an outermost side of the cross section; a second region provided between the first region and the third region at the cross section and having characteristics different from characteristics of the first region and the third region, wherein a shape formed by a boundary between the first region and the second region at the cross section is non-hexagonal.

Abstract: A group 13 nitride crystal having a hexagonal crystal structure contains at least a nitrogen atom and at least one metal atom selected from a group consisting of B, Al, Ga, In and Tl. Dislocation density of basal plane dislocations in a cross section parallel to a c-axis is 104 cm?2 or more.

Abstract: An optical device includes: a light source that emits a light beam; a deflector that deflects the light beam in a main-scanning direction; and a scanning/image-forming optical system that includes a scanning lens that causes the light beam deflected by the deflector to converge to a scanned surface to form an image on the scanned surface. The scanning lens has refractive index gradient. At least one surface of the scanning lens is a tilt-decentered surface that has a tilt angle, which depends on a position in the main-scanning direction, in a sub-scanning direction. The tilt angle is set so as to compensate for variation, which results from the refractive index gradient, in direction of the light beam in the sub-scanning direction.

Abstract: A light beam scanning device scans a luminous flux irradiated from a light source and deflected by a deflector to a scanned surface through an optical system having a set of mirrors. A apparatus, such as the light beam scanning device, further includes a scanning line curve adjusting device to bend a first mirror of the set of mirrors so as to correct a curve in a scanning line on the scanned surface, and a scanning line tilt adjusting device to change orientation of a second mirror of the set of mirrors so as to correct a tilt in the scanning line on the scanned surface. The light beam scanning device may be provided in an image forming apparatus.

Abstract: A light source device includes a light source that includes a vertical cavity surface emitting laser; a drive circuit that drives the light source; and a circuit board that includes at least one mounting surface on which the light source and the drive circuit are mounted. The light source is mounted on a first area of the mounting surface, the drive circuit is mounted on a second area of the mounting surface, and a highest end of the first area is at a same height or lower than a lowest end of the second area with respect to a gravity direction.

Abstract: A light beam splitting element that is arranged on an optical path of a light beam emitted from a VCSEL element splits an incident light beam into a first light beam and a second light beam. An optical system focuses the first light beam on the scanning surface and moves an optical spot formed by a focused light beam on the scanning surface in the main scanning direction. A light receiving element that is mounted on a circuit board receives the second light beam. A dust-proof member bridges a space between the circuit board and a circuit-board holding member that holds the circuit board and surrounds the light receiving element.

Abstract: A light beam splitting element that is arranged on an optical path of a light beam emitted from a VCSEL element splits an incident light beam into a first light beam and a second light beam. An optical system focuses the first light beam on the scanning surface and moves an optical spot formed by a focused light beam on the scanning surface in the main scanning direction. A light receiving element that is mounted on a circuit board receives the second light beam. A dust-proof member bridges a space between the circuit board and a circuit-board holding member that holds the circuit board and surrounds the light receiving element.

Abstract: A light source device includes a light source that includes a vertical cavity surface emitting laser; a drive circuit that drives the light source; and a circuit board that includes at least one mounting surface on which the light source and the drive circuit are mounted. The light source is mounted on a first area of the mounting surface, the drive circuit is mounted on a second area of the mounting surface, and a highest end of the first area is at a same height or lower than a lowest end of the second area with respect to a gravity direction.