A lens accessory (1) is detachably attached to a lens barrel (2), and includes a first holder (104) and a second holder (105) for holding the lens barrel, an operation member (102) that moves at least one holder of the first holder and the second holder between a first position and a second position, and a biasing mechanism (110) that applies a biasing force to the at least one holder so as to hold the lens barrel, the biasing mechanism includes a first biasing member and a moving member that moves the at least one holder from the first position to the second position according to an operation of the operation member via the first biasing member, and when the at least one holder contacts the lens barrel, the first biasing member is displaced by the moving member.

A lens accessory (1) is detachably attached to a lens barrel (2), and includes a first holder (104) and a second holder (105) for holding the lens barrel, an operation member (102) that moves at least one holder of the first holder and the second holder between a first position and a second position, and a biasing mechanism (110) that applies a biasing force to the at least one holder so as to hold the lens barrel, the biasing mechanism includes a first biasing member and a moving member that moves the at least one holder from the first position to the second position according to an operation of the operation member via the first biasing member, and when the at least one holder contacts the lens barrel, the first biasing member is displaced by the moving member.

An add-on device for an image scanner for scanning barcodes is provided. The add-on device includes a housing mounted to the standard range lens front on an image scanner, and a lens holder. The lens holder has a first position for holding a first lens, a second position being an aperture, and a third position for holding a second lens. A high-density lens is mounted in the first position. An extended range lens is mounted in the third position. The lens holder is mounted in the housing and is transverse to the optical axis of the standard range lens of the image scanner. Further, the lens holder is movable within the housing in order to alternately position the high-density lens, the aperture, and the extended range lens to be in alignment with the optical axis of the standard range lens of the image scanner.

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 optical converter 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 optical converter system; and the fourth lens is bonded to either one or both of the third lens and the fifth lens.

An add-on device for an image scanner for scanning barcodes is provided. The add-on device includes a housing mounted to the standard range lens front on an image scanner, and a lens holder. The lens holder has a first position for holding a first lens, a second position being an aperture, and a third position for holding a second lens. A high-density lens is mounted in the first position. An extended range lens is mounted in the third position. The lens holder is mounted in the housing and is transverse to the optical axis of the standard range lens of the image scanner. Further, the lens holder is movable within the housing in order to alternately position the high-density lens, the aperture, and the extended range lens to be in alignment with the optical axis of the standard range lens of the image scanner.

A night vision device, comprising a first light-sensitive chip, a first lens group (101), a first display screen, an image processing system and a control system for adjusting an imaging range of the first light-sensitive chip by adjusting times of optical zooming of the first lens group and/or digital zooming of the image processing system. The night vision device further comprises an auxiliary illumination module (103), which comprises an auxiliary light source and a light guiding cavity; the auxiliary light source at least can emit infrared light; a light ray emitted by the auxiliary light source is emitted via the light guiding cavity; the light guiding cavity has a movable adjustment component for adjusting an irradiation range of the emitted light ray in a manual manner or by means of automatic control by the control system; and the irradiation range is adapted to the imaging range of the first light-sensitive chip. The night vision device according to the present invention can improve a night visual range and imaging quality without changing the level of hardware.

A night vision device, comprising a first light-sensitive chip, a first lens group (101), a first display screen, an image processing system and a control system for adjusting an imaging range of the first light-sensitive chip by adjusting times of optical zooming of the first lens group and/or digital zooming of the image processing system. The night vision device further comprises an auxiliary illumination module (103), which comprises an auxiliary light source and a light guiding cavity; the auxiliary light source at least can emit infrared light; a light ray emitted by the auxiliary light source is emitted via the light guiding cavity; the light guiding cavity has a movable adjustment component for adjusting an irradiation range of the emitted light ray in a manual manner or by means of automatic control by the control system; and the irradiation range is adapted to the imaging range of the first light-sensitive chip. The night vision device according to the present invention can improve a night visual range and imaging quality without changing the level of hardware.

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.

An add-on device for an image scanner for scanning barcodes is provided. The add-on device includes a housing mounted to the standard range lens front on an image scanner, and a lens holder. The lens holder has a first position for holding a first lens, a second position being an aperture, and a third position for holding a second lens. A high-density lens is mounted in the first position. An extended range lens is mounted in the third position. The lens holder is mounted in the housing and is transverse to the optical axis of the standard range lens of the image scanner. Further, the lens holder is movable within the housing in order to alternately position the high-density lens, the aperture, and the extended range lens to be in alignment with the optical axis of the standard range lens of the image scanner.