Pentax Corporation

Hoya Corporation

Pentax Ricoh Imaging Company, Ltd.

Yutaka Takakubo

Eijiroh Tada

Shuichi Takeuchi

Toshiki Nakamura

Naomi Matsumoto

Yoshitake Tanno

Akitoshi Usui

Koichi Maruyama

Takashi Iizuka

Masaru Eguchi

Koichi Sato

Yoshihiro Hama

Shimpei Shinozaki

Yasushi Suzuki

Kazuo Sugitani

Toshimitsu Saito

Yasushi Tsutsumi

An optical element includes a glass body including a colored layer provided inside the glass body and positioned at an optical function surface of the optical element. An optical apparatus including the optical element is also provided.

Optical element and optical apparatus

An optical element including a glass body is provided. The optical element includes a colored layer provided inside the glass body and positioned outside an effective aperture of the optical element. Coloring of the colored layer is a reduction pigment occurring in a glass component of the glass body. The colored layer suppresses occurrence of stray light and obtains sufficient light-shielding properties, so that a superior image quality can be achieved.

An imaging optical system includes a positive or negative first lens group, a diaphragm and a positive second lens group. The first lens group includes a positive lens element, provided closest to the object side, that has an aspherical surface on the object side thereof, the aspherical surface including a paraxial convex surface convexing toward the object side. This aspherical surface has a curvature that is positive along a meridional cross-section at the paraxial portion thereof, and the curvature of the meridional cross-section changes from a positive value to a negative value in an area within 75% of an effective aperture from the paraxial portion toward the periphery of the aspherical surface.

Imaging optical system

The object-side surface of a negative lens element closest to the object side within a first lens group includes a paraxial convex surface and a peripheral surface having a curvature less than that of the paraxial surface. The image-side surface of a last lens element of a second lens group includes a paraxial concave surface and a peripheral surface having an inflection point changing from positive to negative values. 0.10&#x3c;La/TL&#x3c;0.31, and 0.35&#x3c;Bh&#x3c;0.70 are satisfied; La: distance from the object-side surface of the negative lens element, closest to the object side, to an axial light-bundle restriction diaphragm closest to the object side; TL: distance from the object-side surface of this negative lens element to an imaging surface; Bh: height to an inflection point on the image side of the lens element closest to the image side divided by the effective radius thereof.

An imaging optical system includes a positive or negative first lens group including a negative lens element closest to the object, a diaphragm, and a positive second lens group. The negative lens element closest to the object has an object-side aspherical surface including a paraxial convex surface, a paraxial curvature that is the greatest within the effective aperture, and a portion within the effective aperture having a curvature less than &#xbd; of the paraxial curvature. These conditions are satisfied:1/&#x3c;1.351/&#x3e;0.4&#x2212;2.5&#x3c;1/&#x3c;&#x2212;1.3&#x3e;56'f' designates the overall focal length; f1, R1 and D1 respectively designate the focal length, paraxial radius of curvature of an object-side surface, and thickness, of the negative lens element closest to the object; and V designates the Abbe number regarding the d-line of a lens element, within the second lens group, closest to the diaphragm.

An imaging optical system includes a positive or negative first lens group including a negative lens element closest to the object, a diaphragm, and a positive second lens group. The negative lens element closest to the object has an object-side aspherical surface including a paraxial convex surface, a paraxial curvature that is the greatest within the effective aperture, and a portion within the effective aperture having a curvature less than &#xbd; of the paraxial curvature. These conditions are satisfied:1/&#x3c;1.351/&#x3e;0.4&#x2212;2.5&#x3c;1/&#x3c;&#x2212;1.3&#x3e;56

A zoom optical system includes a negative first lens group having a first deflection optical element, a positive second lens group, a positive third lens group, a positive fourth lens group, and a second deflection optical element, in that order from the object side. The first lens group is provided at a fixed position relative to an imaging plane. Zooming is performed by moving at least the second and third lens groups so that distances between adjacent lens groups of the first through fourth lens groups change. The third lens group is a focusing lens group which moves along the optical axis during focusing. The following condition (1) is satisfied:0.2&#x3c;3/4&#x3c;1.0&#x2003;&#x2003;(1),wherein f3 designates the focal length of the third lens group, and f4 designates the focal length of the fourth lens group.

Zoom optical system and imaging apparatus provided with the same

An imaging optical system includes a front lens group including a front lens element and a reflector element which reflects a light bundle that exits from the front lens element; and a rear lens group on the image side of the front lens group. The front lens element is a spherically-swingable lens group which suppresses image shake by spherically-swinging about a predetermined spherical-swing center in accordance with vibrations applied to the imaging optical system. The following conditions (1) and (2) are satisfied:&#x3bd;&#x3e;58&#x2003;&#x2003;(1),and&#x3e;3&#x2003;&#x2003;(2),wherein &#x3bd;d designates the Abbe number with respect to the d-line of at least one lens element of the spherically-swingable lens group, f designates the focal length of the imaging optical system, in a state where the focal length is at a maximum, and y designates the maximum image height of the imaging plane.

An imaging optical system, which includes an imaging lens group having at least one lens, and an image side prism that bends light which has passed through the imaging lens group toward an image pickup device arranged at a predetermined position, and wherein the image side prism includes a reflection surface which reflects, toward the image pickup device, incident light proceeding from the imaging lens group and an exit surface from which light reflected from the reflection surface emerges, and wherein the image side prism has a cut surface formed by cutting off a vertex portion between the reflection surface and the exit surface such that a whole normal light incident area within which normal light is incident on the reflection surface remains, and the cut surface is a non-diffusing surface.

Imaging optical system and imaging apparatus

An imaging optical system, including an imaging lens group, an image side prism having an entrance surface a reflection surface and an exit surface from which light exits toward an image pickup device, and a first shielding member shielding at least a part of a region on the entrance surface, wherein the region on the entrance surface is located from an edge line of an apex between the entrance surface and the exit surface to a position corresponding to a height h from the edge line, and when L represents a length of the exit surface, &#x3b1; represents an angle formed between the reflection surface and the exit surface, n represents a refractive index of a surrounding area of the image side prism, and n' represents a refractive index of the image side prism, the height h satisfies a following condition: h=L&#xd7;cos {&#x3b1;+sin(n/n&#x2032;)}.

An apparatus for detecting a focus state has an optical image-forming system that forms an object image, a plurality of line sensors that is arranged on a projected area of the optical image-forming system; a plurality of monitor sensors that is arranged on the projected area along the direction of a line-sensor array, each monitor sensor being adjacent to a corresponding line sensor and monitoring an amount of light incident on the corresponding line sensor; and a signal processor that outputs image-pixel signals corresponding to the object image on the basis of electric charges accumulated in the plurality of line sensors. At least an endmost monitor sensor corresponding to an endmost line sensor is arranged on the center-facing side of the endmost line sensor.

Apparatus for detecting focus

A focus detection optical system includes a condenser lens positioned behind an expected image plane of a photographing lens, an auxiliary lens positioned behind the condenser lens, and a separator lens including a pair of lenses behind the auxiliary lens. An object image formed on the expected image plane is divided into two images by the pair of lenses and reformed on a pair of areas on a sensor. The auxiliary lens is a plastic lens having a negative refractive power. The separator lens is a glass lens or a hybrid lens consisting of a glass substrate and a plastic lens having a curved surface which is layered onto the glass substrate, and the focus detection optical system satisfies the following condition (1):0.068&#x3c;&#x3c;0.090&#x2003;&#x2003;(1),wherein mand mdesignate magnifications of first and second surfaces, respectively, of the auxiliary lens.

Focus detection optical system

A scanning lens for an imaging optical system converges a beam emitted by a light source and deflected by a deflector on a target surface to form a beam spot scanning in a main scanning direction thereon. The scanning lens includes a plastic lens formed by injection molding, which has a diffractive lens structure on at least one surface thereof. The diffractive lens structure has a plurality of annular zones arranged concentrically about a rotational axis. Each annular zone has a diffracting surface that diffracts the light beam passing therethrough. The diffractive lens structure has stepped surfaces each connecting adjoining diffracting surfaces. In a plane including the rotational axis and parallel with the main scanning direction, the stepped surfaces are inclined with respect to the rotational axis so that stress working between a metallic molding for the plastic lens and each of the stepped surfaces in demolding is reduced.

Diffractive lens and scanning lens formed with diffractive lens

A scanning optical system is provided with a light source configured to emit a plurality of beams, a deflecting device configured to deflect the plurality of beams simultaneously to scan in a main scanning direction, and an imaging optical system configured to converge the plurality of beams on a plurality of target surfaces to form a plurality of beam spots scanning on the plurality of target surfaces, respectively.

Tandem type scanning optical system

There is provided a scanning optical system, which is provided with a light source that emits at least one beam, a polygonal mirror, and an imaging optical system that converges the at least one beam deflected by the polygonal mirror to form at least one beam spot on a surface to be scanned. The at least one beam incident on the polygonal mirror is inclined in an auxiliary scanning direction which is perpendicular to the main scanning direction. Further, at least one lens surface of the imaging optical system is configured such that a beam reflected therefrom proceeds toward an outside region of the polygonal mirror.

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Saitama, Japan

Yutaka Takakubo