Abstract: A polygon mirror includes: a base body having a plurality of side surfaces, a first surface adjacent to the plurality of side surfaces, and a second surface adjacent to the plurality of side surfaces and opposite to the first surface; and a film formed on the plurality of side surfaces and extending from the plurality of side surfaces over the first surface and the second surface, wherein the film includes: a first region formed on the first surface along the plurality of side surfaces; a second region formed on the second surface along the plurality of side surfaces, and wherein a first volume of the first region and a second volume of the second region are different from each other.

Abstract: An optical system 10 includes a front group 11, a light shielding member 4, and a rear group 12 disposed in order from a side of an object to a side of an image. The light shielding member 4 has an opening. The rear group 12 has a diffraction surface 5 and an aspherical surface 6. The aspherical surface 6 in a first section has a non-circular-arc shape. The grating spacing of the diffraction surface 5 in the first section changes from a center portion toward a peripheral portion to include an extremum value at the center portion. In the first section, the shape of at least one of a base surface of the diffraction surface 5 and an optical surface disposed closer than the diffraction surface 5 to the side of the object is asymmetric with respect to a normal line at a vertex thereof.

Abstract: Optical system includes a front group, light-shielding member, and rear group that are arranged in this order in direction from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group does not image the object at the opening in first section parallel to the first direction and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. Light beam that is emitted from the front group 11 and that enters the opening is non-parallel light in the first section.

Abstract: A polygon mirror includes: a base body having a plurality of side surfaces, a first surface adjacent to the plurality of side surfaces, and a second surface adjacent to the plurality of side surfaces and opposite to the first surface; and a film formed on the plurality of side surfaces and extending from the plurality of side surfaces over the first surface and the second surface, wherein the film includes: a first region formed on the first surface along the plurality of side surfaces; a second region formed on the second surface along the plurality of side surfaces, and wherein a first volume of the first region and a second volume of the second region are different from each other.

Abstract: In order to provide a polygon mirror which can reduce a light amount difference among respective image heights on a scanned surface with suppressing an increase in size in a light scanning apparatus, the polygon mirror according to the present invention includes a plurality of rectangular reflecting surfaces in which the following condition is satisfied: 0.02<|1?B/A|<0.10 where A represents a reflectivity at a center of the reflecting surface with respect to a light flux which is incident at a predetermined incident angle, and B represents the reflectivity at a predetermined point between the center and an end in the longitudinal direction of the reflecting surface with respect to the light flux which is incident at the predetermined incident angle.

Abstract: Optical system includes front group, light-shielding member, and rear group that are arranged from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group has aspherical surface, does not image the object at the opening in first section parallel to the first direction, and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. The curvature radius of the aspherical surface in the second section at on-axis position in the first direction differs from that at outermost off-axis position in the first direction.

Abstract: Provided is a light source device including a plurality of light emitting points arranged in matrix within a first cross section parallel to a first direction and a second direction. When light emitting points are projected within a second cross section parallel to first direction and a third direction perpendicular to first cross section, light emitting points have equal intervals between projections adjacent to each other. When light emitting points are projected within a third cross section parallel to second and third directions, light emitting points have equal intervals between projections adjacent to each other. An interval between light emitting points adjacent to each other in a row of matrix, an interval between light emitting points adjacent to each other in a column of matrix, an angle between row and column, an angle between column and first direction, and an angle between row and second direction are appropriately set.

Abstract: An optical system 10 includes a front group 11, a light shielding member 4, and a rear group 12 disposed in order from a side of an object to a side of an image. The light shielding member 4 has an opening. The rear group 12 has a diffraction surface 5 and an aspherical surface 6. The aspherical surface 6 in a first section has a non-circular-arc shape. The grating spacing of the diffraction surface 5 in the first section changes from a center portion toward a peripheral portion to include an extremum value at the center portion. In the first section, the shape of at least one of a base surface of the diffraction surface 5 and an optical surface disposed closer than the diffraction surface 5 to the side of the object is asymmetric with respect to a normal line at a vertex thereof.

Abstract: Provided is a light source device including a plurality of light emitting points arranged in matrix within a first cross section parallel to a first direction and a second direction. When light emitting points are projected within a second cross section parallel to first direction and a third direction perpendicular to first cross section, light emitting points have equal intervals between projections adjacent to each other. When light emitting points are projected within a third cross section parallel to second and third directions, light emitting points have equal intervals between projections adjacent to each other. An interval between light emitting points adjacent to each other in a row of matrix, an interval between light emitting points adjacent to each other in a column of matrix, an angle between row and column, an angle between column and first direction, and an angle between row and second direction are appropriately set.

Abstract: Optical system includes front group, light-shielding member, and rear group that are arranged from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group has aspherical surface, does not image the object at the opening in first section parallel to the first direction, and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. The curvature radius of the aspherical surface in the second section at on-axis position in the first direction differs from that at outermost off-axis position in the first direction.

Abstract: Optical system includes front group, light-shielding member, and rear group that are arranged in this order in direction from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group has aspherical surfaces, does not image the object at the opening in first section parallel to the first direction, and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. Tilt angles of the aspherical surfaces in the second section change in the first direction.

Abstract: Optical system includes front group, light-shielding member, and rear group that are arranged in direction from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group does not image the object at the opening in first section parallel to the first direction and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. F-number for the side of the image in the first section differs from an F-number for the side of the image in the second section.

Abstract: Optical system includes a front group, light-shielding member, and rear group that are arranged in this order in direction from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group does not image the object at the opening in first section parallel to the first direction and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. Light beam that is emitted from the front group 11 and that enters the opening is non-parallel light in the first section.

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

Abstract: An optical scanning device includes a deflector for deflecting a light beam to optically scan a scanned region on a scanned surface in a main scanning direction, and an imaging optical system for guiding the light beam deflected by the deflector, to the scanned surface. The imaging optical system includes an imaging optical element in which, in the main scanning direction, a distance to an optical axis from one effective end portion through which a light beam that enters one end portion of the scanned region passes is longer than a distance to the optical axis from another effective end portion through which a light beam that enters another end portion of the scanned region passes. In the imaging optical element, a thickness in an optical axis direction of the one effective end portion is thinner than a thickness in the optical axis direction of the other effective end portion.

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

Abstract: There is provided a light scanning apparatus that is free from main scanning jitter and allows size reduction of a deflector. The light scanning apparatus has a plurality of light sources, a deflector that deflects a plurality of light fluxes emitted from a plurality of light sources to scan a plurality of scanned surfaces along a main scanning direction, and a first stop arranged between the plurality of light sources and the deflector and provided with an aperture that regulates the width of the plurality of light fluxes with respect to the main scanning direction. The number of apertures of the first stop is smaller than the number of light sources.