An optical imaging device for a microscope includes an objective and an optical system configured to interact with the objective for optically imaging an object selectively in a first operating mode and a second operating mode. The optical system includes a first optical subsystem associated with the first operating mode, and a second optical subsystem associated with the second operating mode. The first optical subsystem is configured to form a first image of the object with a first magnification. The second optical subsystem is configured to form a second image of the object with a second magnification that is less than the first magnification. The second optical subsystem includes an optical module insertable into the optical path for selecting the second operating mode. The optical module includes a lens element with a positive refractive power.

A converter optical system includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having negative refractive power; and a fifth lens having positive refractive power; wherein the first to fifth lenses are sequentially disposed in numerical order from the first lens to the fifth lens from an object side of the converter optical system to an image side of the converter optical system; and the fourth lens is bonded to either one or both of the third lens and the fifth lens.

A converter optical system includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having negative refractive power; and a fifth lens having positive refractive power; wherein the first to fifth lenses are sequentially disposed in numerical order from the first lens to the fifth lens from an object side of the converter optical system to an image side of the converter optical system; and the fourth lens is bonded to either one or both of the third lens and the fifth lens.

An object of the present invention is provide a coded aperture imaging apparatus that has a refocusing function and can change an angle of view. An imaging apparatus includes an imaging apparatus main body including a coded aperture, an imaging element that outputs a signal indicating a projected image of a subject, and an image restoration unit that reconstructs an image of a spatial domain based on the signal, and a lens attached to the imaging apparatus main body on a subject side from the coded aperture and changes an imaging angle of view in a state where the lens is attached to the imaging apparatus main body with respect to an imaging angle of view in a state where the lens is not attached to the imaging apparatus main body, in which the projected image is formed on the imaging element by the lens and the coded aperture.

This disclosure describes an afocal attachment that allows for alteration of received electromagnetic radiation (or “light”) prior to entry into the telescope. For example, a rifle scope may have a base magnification of 2×, and the afocal attachment may allow magnification of a received image at levels ranging from 2× to 4×. In this example, the entire telescope system with the afocal attachment installed will have an overall magnification of 4× to 8×. In another example, the magnification of the telescope can be increased, transforming a telescope with a 4× magnification into a telescope with a higher effective magnification. In some instances the afocal attachment's optical axis can be configured to permit independent adjustment, allowing for easy removal and reinstallation of the afocal attachment without a need to re-adjust the telescope itself.

This disclosure describes an afocal attachment that allows for alteration of received electromagnetic radiation (or “light”) prior to entry into the telescope. For example, a rifle scope may have a base magnification of 2×, and the afocal attachment may allow magnification of a received image at levels ranging from 2× to 4×. In this example, the entire telescope system with the afocal attachment installed will have an overall magnification of 4× to 8×. In another example, the magnification of the telescope can be increased, transforming a telescope with a 4× magnification into a telescope with a higher effective magnification. In some instances the afocal attachment's optical axis can be configured to permit independent adjustment, allowing for easy removal and reinstallation of the afocal attachment without a need to re-adjust the telescope itself.

A reduction optical system disposed on an image side of a main optical system, a composite focal length of the main optical system and the reduction optical system being shorter than a focal length of the main optical system, includes a first lens element disposed closest to an object side and having a positive refractive power, a second lens element disposed closest to an image side and having a positive refractive power, and a positive lens and a negative lens disposed between the first lens element and the second lens element.

The rear converter lens consists of, in order from an object side: a first lens group that has a positive refractive power; a second lens group that has a negative refractive power; and a third lens group that has a positive refractive power. The first lens group consists of a cemented lens in which a negative lens concave toward the image side and a positive lens convex toward the object side are cemented. The second lens group consists of a cemented lens in which a negative lens concave toward the image side, a positive lens convex toward both sides, and a negative lens concave toward the object side are cemented. The third lens group consists of a cemented lens in which a positive lens convex toward the object side and a negative lens are cemented. The rear converter lens satisfies predetermined Conditional Expressions (1) and (2).

The rear converter lens consists of, in order from an object side: a first lens group that has a positive refractive power; a second lens group that has a negative refractive power; and a third lens group that has a positive refractive power. The first lens group consists of a cemented lens in which a negative lens concave toward the image side and a positive lens convex toward the object side are cemented. The second lens group consists of a cemented lens in which a negative lens concave toward the image side, a positive lens convex toward both sides, and a negative lens concave toward the object side are cemented. The third lens group consists of a cemented lens in which a positive lens convex toward the object side and a negative lens are cemented. The rear converter lens satisfies predetermined Conditional Expressions (1) and (2).

This disclosure describes an afocal attachment that allows for alteration of received electromagnetic radiation (or light) prior to entry into the telescope. For example, a rifle scope may have a base magnification of 2, and the afocal attachment may allow magnification of a received image at levels ranging from 2 to 4. In this example, the entire telescope system with the afocal attachment installed will have an overall magnification of 4 to 8. In another example, the magnification of the telescope can be increased, transforming a telescope with a 4 magnification into a telescope with a higher effective magnification. In some instances the afocal attachment's optical axis can be configured to permit independent adjustment, allowing for easy removal and reinstallation of the afocal attachment without a need to re-adjust the telescope itself.