Abstract: A diffusing plate is formed so as to have a surface having a larger surface roughness than a predetermined wavelength and having an aperiodic roughness shape. A plurality of fine concave/convex portions are formed on the surface so as to be regularly arranged within a cycle equal to and smaller than a predetermined wavelength.

Abstract: A light quantity distribution control element includes a substrate of 20 mm×20 mm×3 mm made of a material that transmits light, such as optical glass or acryl, and a antireflective structure provided on a surface of the substrate. As the antireflective structure, a conical antireflective structure of a pitch of 0.15 ?m (periodic structure having conical convexities) is formed. This corresponds to a antireflective structure having a pitch of a wavelength or less in the ultraviolet band (150 nm to 400 nm) at the time when ultraviolet light is used as incident light.

Abstract: A light-absorbing member has a substrate (101, 111) made of a material capable of absorbing light of which reflection is to be prevented, and an antireflection structure (102, 112, 303) having structural elements arranged on the surface of the curve in an array form at a period smaller than the wavelength of the light. The substrate having the shape of a curve viewed from a macroscopic viewpoint. The structural elements have a shape protruding or being recessed from a reference face corresponding to the curve of the substrate, and are arranged so that the straight lines connecting the reference face to the tips of the respective structural elements are nearly parallel to one another.

Abstract: A distance-measuring optical apparatus for measuring a distance to an object as a target comprises an imaging optical system; an image sensor; a driving section for moving at least the imaging optical system substantially perpendicular to an optical axis; an image sensor control section for outputting a periodical timing signal for designating a timing at which the image sensor takes an object image; and a driving control section for controlling the driving section to reciprocate the imaging optical system. The timing signal is periodically output when the imaging optical system is located near two positions away from each other in a direction substantially perpendicular to the optical axis. The distance-measuring optical apparatus further comprises an image processing operation section for finding, through an operation, a distance from the imaging optical system to the object using the image signal when the imaging optical system is at each of the two positions.

Abstract: The over-field type optical scanner includes a first imaging optical system disposed between a light source and a rotating polygon mirror for forming, on one surface of the rotating polygon mirror, a linear image with a width larger than a width along a main scanning direction of the one surface of the rotating polygon mirror; and a second imaging optical system composed of a curved mirror for focusing, on a scan surface, a light beam having been reflected by the rotating polygon mirror. The first imaging optical system includes a first conversion optical system for converting the light beam emitted from the light source into a divergent light beam with respect to the main scanning direction and into a convergent light beam with respect to the sub scanning direction; and a second conversion optical system having a refracting power in the main scanning direction.

Abstract: An object of the present invention is to provide a light-absorbing member capable of preventing the reflection of light at the interface with air and absorbing the light substantially completely. A light-absorbing member has a substrate (101) made of a material capable of absorbing light of which reflection is to be prevented, and an antireflective structure (102) including structural elements, the structural elements forming an array with a period shorter than the wavelength of the light.

Abstract: A single lens element used for converting a divergent pencil of rays, radiated from a light source, into a predetermined convergent state, wherein the single lens element is made from a resin and has a positive optical power due to a refraction effect and a positive optical power due to a diffraction effect, the diffraction effect is based on a diffraction structure formed on at least one of an incident side surface and an exit side surface of the single lens element, and the following expressions are satisfied: 0.1<NA<0.3 0.4<T/f<0.75 2.2<fr/f<3 here, f is a focal length of the entire single lens element, fr is a focal length due to the refraction effect of the single lens element, T is a thickness of the single lens element on an optical axis, and NA is a numerical aperture of a single lens element at an incident side.

Abstract: An illumination optical system includes a light source for emitting a plurality of different colors of light, a plurality of rotating optical scanners, and a plurality of scanning lenses. Each of the optical scanners has a reflecting surface that is formed helically around a cylindrical body. The different colors of light enter the respective reflecting surfaces in the direction parallel to the rotation axis, are reflected therefrom, and pass through the scanning lenses, so that each color of light is magnified and then scans the region to be illuminated sequentially. This makes it possible to provide an illumination optical system that can improve scanning linearity, lower noise because of its reduced wind resistance, and achieve reduction in the cost and power consumption.

Abstract: A light quantity distribution control element includes a substrate of 20 mm×20 mm×3 mm made of a material that transmits light, such as optical glass or acryl, and a antireflective structure provided on a surface of the substrate. As the antireflective structure, a conical antireflective structure of a pitch of 0.15 ?m (periodic structure having conical convexities) is formed. This corresponds to a antireflective structure having a pitch of a wavelength or less in the ultraviolet band (150 nm to 400 nm) at the time when ultraviolet light is used as incident light.

Abstract: A single lens element used for converting a divergent pencil of rays, radiated from a light source, into a predetermined convergent state, wherein the single lens element is made from a resin and has a positive optical power due to a refraction effect and a positive optical power due to a diffraction effect, the diffraction effect is based on a diffraction structure formed on at least one of an incident side surface and an exit side surface of the single lens element, and the following expressions are satisfied: 0.1<NA<0.3 0.4<T/f<0.75 2.2<fr/f<3 here, f is a focal length of the entire single lens element, fr is a focal length due to the refraction effect of the single lens element, T is a thickness of the single lens element on an optical axis, and NA is a numerical aperture of a single lens element at an incident side.

Abstract: An illumination optical system includes a light source for emitting a plurality of different colors of light, a plurality of rotating optical scanners, and a plurality of scanning lenses. Each of the optical scanners has a reflecting surface that is formed helically around a cylindrical body. The different colors of light enter the respective reflecting surfaces in the direction parallel to the rotation axis, are reflected therefrom, and pass through the scanning lenses, so that each color of light is magnified and then scans the region to be illuminated sequentially. This makes it possible to provide an illumination optical system that can improve scanning linearity, lower noise because of its reduced wind resistance, and achieve reduction in the cost and power consumption.

Abstract: An optical scan apparatus includes an optical deflection unit (4), an image formation optical system (3), and curved surface mirrors (7a to 7d). Light fluxes from the image formation optical system (3) come onto the deflection surface (4a) of die optical deflection unit (4) in an oblique direction. Light fluxes from the optical deflection unit (4) come onto the curved surface mirrors (7a to 7d) in an oblique direction. When a boundary is a plane (6) including a normal at the center of the deflection surface (4a) and parallel to the main scan direction, the curved surface mirrors (7a to 7d) are arranged in the same space divided by the boundary and the scan speeds of fluxes scanning the surfaces to be scanned (8a to 8d) are almost identical. Thus, it is possible to obtain identical drive frequencies of the light sources (1a to 1d), thereby simplifying the circuit.

Abstract: A reflection of unnecessary light, which should be prevented, can be suppressed, and occurrence of stray light can be reduced using a member having an antireflection structure, comprising a plate-like portion 2, and an aperture portion 3 formed in the plate-like portion 2, wherein the antireflection structure having an aspect ratio of 1 or more and comprising structural elements arranged in an array form at a period smaller than the shortest wavelength of light, the reflection of which should be prevented, is formed on an inner wall 4 of the aperture portion 3.

Abstract: An illumination optical system includes a light source for emitting a plurality of different colors of light, a plurality of rotating optical scanners, and a plurality of scanning lenses. Each of the optical scanners has a reflecting surface that is formed helically around a cylindrical body. The different colors of light enter the respective reflecting surfaces in the direction parallel to the rotation axis, are reflected therefrom, and pass through the scanning lenses, so that each color of light is magnified and then scans the region to be illuminated sequentially. This makes it possible to provide an illumination optical system that can improve scanning linearity, lower noise because of its reduced wind resistance, and achieve reduction in the cost and power consumption.

Abstract: A method for manufacturing an optical element comprises a step of press molding an optical element material 6 disposed between an upper press head (7) and its paired lower press head (8), wherein in the upper press head (7) and/or the lower press head (8) is formed a groove-like component that forms a non-cylindrical face or a cylindrical face as an optically effective component in the optical element material (6). This makes it possible to obtain an optical element with stable face shape precision, boosts productivity, and is also advantageous in terms of cost.

Abstract: An image reading device comprising a rotary polygon mirror (6) for scanning a light flux from a light source (1), an imaging optical system (4) for forming on a reflection plane of the mirror (6) a linear image larger than the width in a main scanning direction of the one reflection plane, and a curved-face mirror (7), wherein the light source (1), the imaging optical system (4), the rotary polygon mirror (6) and the curved-face mirror (7) are disposed in different positions in a sub-scanning direction, a light flux from the imaging optical system (4) shines obliquely onto the polygon mirror (6), and a light flux reflected off the mirror (6) beams obliquely onto the curved-face mirror (7). Since one curved-face mirror can beam a light flux reflected from the rotary polygon mirror onto a surface to be scanned and the rotary polygon mirror having a small inscribed radius and many reflection planes can be used, satisfactory optical performance and high-speed feature can be realized.

Abstract: By a first image forming optical system (42a to 42d), a plurality of light beams from light sources (41a to 41d) form linear images on a common deflecting surface (46) of an optical deflector (44). Light beams reflected off the optical deflector (44) are reflected by a plurality of curved surface mirrors (45a to 45d) and are allowed to scan over photosensitive members (4a to 4d), respectively. The plurality of curved surface mirrors (45a to 45d) are disposed on the same side with respect to a plane that includes a normal line at a center of the deflecting surface (46) and is parallel to a main scanning direction. Further, curved surfaces of the plurality of curved surface mirrors (45a to 45d) vary in shape. Thus, a tandem type color image forming apparatus that achieves low cost and has excellent optical performance and an optical scanning device that is used favorably in the color image forming apparatus can be provided.

Abstract: An illuminating device comprising a light source for emitting a plurality of light beams (207, 208, 209) of different colors, a plurality of rotating beam scanners (102, 103, 104) and a plurality of scanning lenses (109, 110, 111). The beam scanners have spiral reflection surfaces (102, 103, 204) formed on the outer peripheries of cylindrical bodies, Each colored light beam is shone onto each reflection surface from a direction parallel to a rotating axis, and magnified by each scanning lens after reflected to scan an illuminated area with a plurality of beams of different colors one after another. Accordingly, the illuminating device can enhance scanning linearity, reduce noise due to a minimal windage loss, and decrease costs and power consumption.

Abstract: A distance-measuring optical apparatus for measuring a distance to an object as a target comprises an imaging optical system; an image sensor; a driving section for moving at least the imaging optical system substantially perpendicular to an optical axis; an image sensor control section for outputting a periodical timing signal for designating a timing at which the image sensor takes an object image; and a driving control section for controlling the driving section to reciprocate the imaging optical system. The timing signal is periodically output when the imaging optical system is located near two positions away from each other in a direction substantially perpendicular to the optical axis. The distance-measuring optical apparatus further comprises an image processing operation section for finding, through an operation, a distance from the imaging optical system to the object using the image signal when the imaging optical system is at each of the two positions.

Abstract: By a first image forming optical system (42a to 42d), a plurality of light beams from light sources (41a to 41d) form linear images on a common deflecting surface (46) of an optical deflector (44). Light beams reflected off the optical deflector (44) are reflected by a plurality of curved surface mirrors (45a to 45d) and are allowed to scan over photosensitive members (4a to 4d), respectively. The plurality of curved surface mirrors (45a to 45d) are disposed on the same side with respect to a plane that includes a normal line at a center of the deflecting surface (46) and is parallel to a main scanning direction. Further, curved surfaces of the plurality of curved surface mirrors (45a to 45d) vary in shape. Thus, a tandem type color image forming apparatus that achieves low cost and has excellent optical performance and an optical scanning device that is used favorably in the color image forming apparatus can be provided.