Accession Number : ADD014304

Title :   A Scheiner-Principle Vernier Optometer.

Descriptive Note : Patent Application, Filed 23 Jun 89,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Cushman, William B

Report Date : 23 Jun 1989

Pagination or Media Count : 20

Abstract : This patent application discloses a method and optometer apparatus for measuring the dark focus of accommodation. In a preferred embodiment, the optometer apparatus includes: a pinhole aperture plate having first and second horizontally positioned apertures disposed on opposite sides of a first optical axis; first and second orthogonally-oriented polarizing filters respectively covering the first and second horizontally positioned apertures; a positive lens having an optical axis on the first optical axis and being positioned at a distance of approximately one focal length from the pinhole aperture plate; a lens system having an optical axis on the first optical axis; a slit aperture plate having a vertical slit and being disposed on the first optical axis and between the positive lens and the lens system; third and fourth vertically positioned polarizing filters selectively disposed adjacent to the slit aperture plate to divide the slit vertically, a monochromatic light source for propagating light along the first optical axis through the lens system; and movable means attached to the slit aperture plate, the lens system and the monochromatic light source for moving the slit aperture plate. (jhd)

Descriptors :   *OPTOMETERS, *PATENT APPLICATIONS, LENGTH, LENSES, LIGHT, LIGHT SOURCES, MONOCHROMATIC LIGHT, OPTICAL PROPERTIES, POLARIZING FILTERS, PROPAGATION, APERTURES, DARK ADAPTATION

Subject Categories : Medical Facilities, Equipment and Supplies

Distribution Statement : APPROVED FOR PUBLIC RELEASE