többfókuszú

Többfókuszú is a Hungarian adjective meaning having multiple focal points. In optics and vision science it is used to describe devices or systems that provide functionality at more than one focal length or working distance. The term is common in ophthalmology, optometry, photography, and imaging, where a single element or assembly is designed to cover near, intermediate, and/or far vision.

In vision correction, többfókuszú látáskorrekciók include progressive eyeglass lenses and multifokális kontaktlencsék. These lenses combine several focal powers within one piece, enabling the wearer to see clearly at different distances without changing glasses. They may use distinct refractive zones or a smooth gradient between powers. Adapting to such lenses can take time, and users may experience initial distortions or halos.

In optics and imaging outside vision correction, többfókuszú systems can refer to lenses or assemblies designed for multiple focusing distances or imaging requirements. Such designs may employ layered or aspheric surfaces, refractive zone engineering, or diffractive elements to balance sharpness across distances. The main goal is to provide versatile focus behavior with a single optical element or compact set of elements.

Advantages of többfókuszú solutions include convenience, broader usable range, and reduced need to switch devices. Limitations can include higher cost, potential aberrations during transition between focal powers, and a learning curve for users.

See also: progresszív lencsék, multifokális kontaktlencsék, diffraktív/ refraktív optika.