Image display system

An optical system for a visual display comprising:

• means for projecting a visual image along a central axis;
• a first fresnel lens for receiving said visual image, said first fresnel lens having fresnel grooves facing said means for projecting;
• second and third fresnel lenses forming a liquid doublet first fresnel lens pair disposed in front of said first fresnel lens, said first fresnel lens pair having fresnel grooves facing each other and a liquid disposed therebetween, said liquid having predetermined indexes of refraction and dispersion for color correcting the system;
• fourth and fifth fresnel lenses forming a second fresnel lens pair disposed in front of said first fresnel lens pair, said second fresnel lens pair having fresnel grooves facing each other;
• said first, second, third, fourth and fifth fresnel lens being centered on said central axis and extending perpendicular thereto;
• said fresnel grooves being comprised of annular facets having a slope determined by dz/dr where:
• ##EQU2## and C equals the curvature of said annular facets;
• r equals the radical position of said facets;
• K equals a conic constant determined by the physical characteristics of said lenses;
• and D, E, F and G are aspheric terms which determine the aspheric characteristics of said lenses.