Canon Kabushiki Kaisha

University of Arizona

Masatsugu Nakano

Jose Manuel Sasian-Alvarado

Takeyoshi Saiga

Kazuhiko Kajiyama

Keiichiro Ishihara

Tamer T Elazhary

An optical systemincludes, in order from an enlargement side, a front group, an aperture diaphragm, and a rear group, the front groupincluding a refractive surfaceconvex toward the enlargement side, the rear groupincluding a concave reflective surface, and Conditional Expressions of 0.7&#x2264;|Rl|/Ll&#x2264;1.5 and 2&#x2264;|Rm|/Lm&#x2264;7 are satisfied, where a curvature radius of the refractive surfaceis Rl (mm), a distance between the refractive surfaceand the aperture diaphragmis Ll (mm), a curvature radius of the reflective surfaceis Rm (mm), and a distance between the aperture diaphragmand the reflective surfaceis Lm (mm).

Optical system, and imaging apparatus and projecting apparatus having the same

Provided is an optical system including, in order from an object side to an image side, a first lens unit having a negative refractive power, an aperture stop, and a second lens unit having a positive refractive power, in which an average value &#x3b8;IR(G)of partial dispersion ratios of materials of positive lenses included in the second lens unit and an average value &#x3b8;IR(G)of partial dispersion ratios of materials of negative lenses included in the second lens unit are appropriately set, provided that BF and F are a backfocus and a focal length of the optical system at a wavelength of 1050 nm, respectively, and a partial dispersion ratio of a material is &#x3b8;=(Ns&#x2212;Nm)/(Ns&#x2212;Nl), where Ns, Nm, and Nl are refractive indices of the material at wavelengths of 400 nm, 1050 nm, and 1700 nm, respectively.

Optical system and image pickup apparatus including the same

Provided is a zoom lens, including, in order from an object side to an image side, first, second, and third lens units having positive, negative, and positive refractive powers, respectively. The second lens unit moves toward image side during zooming from a wide angle end to a telephoto end, and an interval between adjacent lens units is changed during zooming. The first lens unit includes a lens pair of a positive lens (LP) and a negative lens (LN) that are arranged adjacent to each other. A refractive index of a material at 400 nm wavelength, a refractive index of a material at 1,050 nm wavelength, a refractive index of a material at 1,700 nm wavelength, an Abbe number and a partial dispersion ratio of a material, Abbe numbers and partial dispersion ratios of materials for the positive lens (LP) and the negative lens (LN) are each appropriately set.

Zoom lens and image pickup apparatus including the same

Provided is a zoom lens, including: a negative first lens unit; an aperture stop; and a positive second lens unit, in which the first and second lens units are configured to move so that an interval between the first and second lens units is changed in an optical axis direction, in which the second lens unit includes a positive lens and a negative lens, and in which, when refractive indices of a material with respect to a wavelengths of 400 nm, 1,050 nm and 1,700 nm are respectively represented by Ns, Nm and Nl, and a relative partial dispersion &#x3b8; of the material is expressed as: &#x3b8;=(Ns&#x2212;Nm)/(Ns&#x2212;Nl), an average value &#x3b8;IR(G)of relative partial dispersions of materials of the positive lens in the second lens unit, and an average value &#x3b8;IR(G)of relative partial dispersions of materials of the negative lens in the second lens unit are appropriately set.

Provided is a zoom lens, comprising, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a negative refractive power; and a fourth lens unit having a positive refractive power. The second lens unit and the third lens unit are configured to move along loci different from each other during zooming. At least one lens unit of the first lens unit, the second lens unit, the third lens unit, or the fourth lens unit includes a positive lens and a negative lens that are arranged adjacent to each other, and materials for the positive lens and the negative lens are appropriately set, respectively.

An optical system to form an image on an image plane includes, a catadioptric optical subsystem configured to collect light from an object plane; and a refractive optical subsystem configured to form the image on the image plane, the catadioptric and refractive optical subsystems being arranged in order from the object plane to the image plane along an optical axis of the optical system. A baffle to shut off light traveling toward the image plane without being reflected by the catadioptric optical subsystem is placed in the optical system, in order to form a shielded portion in a center of an exit pupil plane of the optical system, and the catadioptric optical subsystem includes a partially transparent surface around the optical axis of the optical system so that transmissivity of a region, other than the shielded portion, at the exit pupil plane varies in a radial direction of the exit pupil plane.

Optical system with catadioptric optical subsystem

A catadioptric system includes a first catadioptric group, a second catadioptric group, and a lens group disposed in axial alignment with each other. The first catadioptric group includes a solid lens having an input surface, a primary reflective surface, secondary reflective surface and an exit surface. The primary reflective surface is a curved surface concave towards the secondary reflective surface. A light flux entering through the input surface undergoes more than two reflections between the primary and secondary reflective surfaces, prior to exiting through the exit surface. At least one of the primary reflective surface and secondary reflective surface has a continuous and smooth topological profile.

Catadioptric optical system with multi-reflection element for high numerical aperture imaging

A catadioptric optical system includes a first imaging optical system including a catadioptric part configured to condense a light flux from an object and to form an intermediate image of the object, and a second imaging optical system including a dioptric part configured to form an image of the intermediate image on an image surface. The light flux from the object passes through the light transmission part of the first optical element, the negative lens, the backside reflection part of the second optical element, the negative lens, the backside reflection part of the first optical element, the negative lens, and the light transmission part of the second optical element, in this order, and is emitted to the second imaging optical system. An Abbe number of a material of the negative lens is larger than that of a material of the second optical element.

Catadioptric optical system and image-pickup apparatus having the same

A catadioptric lens comprises, a first surface configured to introduce a ray within the catadioptric lens; and a second surface, with a reflective film, configured to reflect the introduced ray to the first surface; the second surface having a first reflection area and a second reflection area surrounded by the first reflection area, wherein the ray, which has been introduced from the first surface and has traveled to the first reflection area, is reflected on the first reflection area by total internal reflection, and the ray, which has been introduced from the first surface and has traveled to the second reflection area, is reflected by the reflective film.

Catadioptric optical element and optical system including same

A catadioptric optical system includes a first imaging optical system that includes a catadioptric part that collects a light beam from an object to form an intermediate image of the object, and a second imaging optical system that includes a refractive part that images the intermediate image on an image plane. The first imaging optical system includes a first optical element, a second optical element, and a negative lens in an optical path between the first and second optical elements, and the first and second optical elements are disposed so that reflection parts of the first and second optical element face each other. A power &#x3c6;n of the negative lens, radii of curvature Rand Rof lens surfaces of the negative lens at an object side and an image side, respectively, and a power &#x3c6;1 of the first imaging optical system are appropriately set.

Catadioptric optical system and image pickup apparatus having the same

A catadioptric optical system includes, in order from an object side to an image side and arranged along an optical axis, a first catadioptric unit, a second catadioptric unit disposed in axial alignment with the first catadioptric unit and with a space therebetween; and a lens group disposed in axial alignment with the first and second catadioptric optical units. Light rays arriving from an object plane undergo a first reflection at the image-side surface of the first catadioptric optical unit, a second reflection at the object-side surface of the first catadioptric optical unit, a third reflection at the image-side surface of the second catadioptric optical unit, and a fourth reflection at the object-side surface of the second catadioptric optical unit. Advantageously, the sum the outward Petzval curvatures is cancelled out by the sum of inward Petzval curvatures.

Catadioptric optical system with total internal reflection for high numerical aperture imaging

An optical system includes a first optical group configured to form, at a first intermediate image plane, a first intermediate image of an object disposed at an object plane; a second optical group and a third optical group configured to form, at an image plane, a final image of the object based on the first intermediate image. The first optical group consists of a solid lens having a first surface and a concave second surface facing the first surface; the solid lens is configured to collect light originated at the object and to reflect thereinside at least twice the collected light. The second optical group includes at least one mangin mirror and the third optical group includes a plurality of lenses. The first, second and third optical groups can appropriately control axial chromatic aberration and Petzval curvature, so that imaging with high NA illumination may be performed.

Growing community of inventors

Tucson, AZ, United States of America

Masatsugu Nakano