Vehicle dashboard instrument magnifying lens assembly - has pref. fresnel lenses with given transverse aberration smaller than observer eye pupil dia. at eye position

摘要

The optical system to magnify an indication field has a lens assembly (1) with a transverse aberration smaller than the pupil dia. of the observer's eye. Pref. the optical system comprises several lenses (2a, 3a) with convex surfaces lying opposite one another and with one of these surfaces aspherical. The transverse aberration may be less than 3 mm at the eye position. One or both lenses may be fresnel lenses or one lens may be a prism. Pref. the indication field of an instrument to be magnified is behind the centre of the lens assembly and other indication fields not needing magnification are behind the edge of the lens assembly. ADVANTAGE - Reduces eye strain from switching between distant objects and dashboard instruments.