PROJECTION WIDE-APERTURE LENS Russian patent published in 2004 - IPC

FIELD: optical instrument making, possibly lens for image transfer from screen of electronic-optic converter to CCD-matrix.

SUBSTANCE: lens includes first component in the form of positive meniscus turned by its concave surface to object space; second component in the form of positive meniscus turned by its concave surface to image space; third component having negative concentric meniscus turned by concave surface to image space; fourth component in the form of negative meniscus cemented of biconcave and biconvex lens; fifth and sixth components in the form of separate positive lens; aperture diaphragm placed between third and fourth components. Lens also includes seventh component in the form of meniscus turned by concave surface to object space. Absolute value of optical activity of seventh component is no more than 0.35 of optical activity of the whole lens. Spacing between sixth and seventh components along optic axis is equal at least to 0.18 of focal length of lens.

EFFECT: increased relative opening of lens, enhanced quality of image due to increased modulation transfer coefficients along the whole visual field.

6 dwg