There is provided an optical imaging system including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens includes a negative refractive power and a concave object-side surface. The second lens includes a concave object-side surface. The fourth lens includes a negative refractive power. The sixth lens includes an inflection point formed on an image-side surface thereof. The first to sixth lenses are sequentially disposed from an object side toward an imaging plane.

An optical system includes a first optical subsystem disposed on an enlargement side and a second optical subsystem disposed on a reduction side with an intermediate image in between. The first optical subsystem includes: a first lens group that is disposed on the enlargement side of a first stop with a first distance, in which other lenses could be disposed but no other lenses are disposed, and is provided on the enlargement side with a first component with negative refractive power; and a second lens group that has positive refractive power, is disposed on the reduction side of the first stop with a second distance, in which other lenses could be disposed but no lenses are disposed, and forms the intermediate image so as to be adjacent on a reduction side of the second lens group and so as to be tilted toward the enlargement side.

An optical system includes a first optical subsystem disposed on an enlargement side and a second optical subsystem disposed on a reduction side with an intermediate image in between. The first optical subsystem includes: a first lens group that is disposed on the enlargement side of a first stop with a first distance, in which other lenses could be disposed but no other lenses are disposed, and is provided on the enlargement side with a first component with negative refractive power; and a second lens group that has positive refractive power, is disposed on the reduction side of the first stop with a second distance, in which other lenses could be disposed but no lenses are disposed, and forms the intermediate image so as to be adjacent on a reduction side of the second lens group and so as to be tilted toward the enlargement side.

A projection apparatus includes a display element that displays an image, a projection optical system that forms a projection image by projecting the image, an imaging unit that includes an imaging optical system which images a first region including an optical axis of the projection optical system in the projection image, and an imaging element which captures an image formed by the imaging optical system, and a processor that controls focus adjustment on a second region not including the optical axis in the projection image based on information acquired from the imaging unit, in which a position of the projection image is changeable by changing a relative position between at least a part of the projection optical system and the display element, and a predetermined conditional expression is satisfied.

An optical system includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, and a fourth lens unit having positive refractive power. During focusing, the first lens unit and the fourth lens unit are fixed, and the second lens unit and the third lens unit are moved. The first lens unit includes a positive lens disposed closest to an object. The fourth lens unit includes a negative lens disposed closest to an image plane.

An optical assembly for an eye-tracking camera includes an aperture stop, a first optical surface, and a second optical surface. The optical assembly is configured to receive non-visible light reflected or scattered by an eye and to direct the non-visible light to an image sensor along an optical path, where the non-visible light is received from an optical combiner of an eye-tracking system. The first optical surface is disposed on the optical path and is configured to correct for field-independent optical aberrations induced by the optical combiner. The second optical surface is disposed on the optical path and is configured to correct for field-dependent optical aberrations induced by the optical combiner.

An optical system includes, in order from an object side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, and a third lens unit having positive refractive power. A distance between adjacent lens units changes during focusing. During focusing from an infinity object to the closest object, the first and third lens units do not move and the second lens unit moves toward the image side. The third lens unit consists of, in order from the object side, a first subunit having positive refractive power, a second subunit having negative refractive power, and a third subunit having positive refractive power. The second subunit moves in a direction including a component in a direction orthogonal to an optical axis during image stabilization. The second subunit includes positive and negative lenses. A predetermined condition is satisfied.

The present disclosure discloses an imaging lens assembly. The imaging lens assembly includes, sequentially from an object side to an image side of the imaging lens assembly, a first lens having a positive refractive power and a convex object-side surface; a second lens having a negative refractive power and a concave image-side surface; and at least one subsequent lens. At least one of the first lens, the second lens, or the at least one subsequent lens is a glass aspheric lens. A transmittance T1 of the imaging lens assembly corresponding to a wave band 650 nm satisfies: T1>85%, a transmittance T2 of the imaging lens assembly corresponding to a wave band 490 nm satisfies: T2>88%, and a transmittance T3 of the imaging lens assembly corresponding to a wave band 430 nm satisfies: T3>75%.

The present disclosure discloses an imaging lens assembly. The imaging lens assembly includes, sequentially from an object side to an image side of the imaging lens assembly, a first lens having a positive refractive power and a convex object-side surface; a second lens having a negative refractive power and a concave image-side surface; and at least one subsequent lens. At least one of the first lens, the second lens, or the at least one subsequent lens is a glass aspheric lens. A transmittance T1 of the imaging lens assembly corresponding to a wave band 650 nm satisfies: T1>85%, a transmittance T2 of the imaging lens assembly corresponding to a wave band 490 nm satisfies: T2>88%, and a transmittance T3 of the imaging lens assembly corresponding to a wave band 430 nm satisfies: T3>75%.

The present invention provides a camera optical lens, including, from an object side to an image side, a first lens having a positive refractive power, a second lens a negative refractive power, a third lens having a positive refractive power, a fourth lens having a negative refractive power, and a fifth lens. At least one of the first lens to the fifth lens has a free-form surface, and the camera optical lens satisfies 0.50≤f3/f≤1.20; and 1.50≤R7/R8, where f denotes a focal length of the camera optical lens, f3 denotes a focal length of the third lens, R7 is a central curvature radius of an object side surface of the fourth lens, and R8 is a central curvature radius of an image side surface of the fourth lens. The camera optical lens has excellent optical performance while meeting requirements of a long focal length and ultra-thinness.