EYEPIECE LENSES
“A foolish faith in authority is the worst enemy of truth.” ― Albert Einstein
Eyepiece   design   in   its   simplest   from   is   a   single   lens   which   is   used   to   magnify   an   object   such   that   the   user   can   view   the   object   at   a   position close   to   the   eye,   while   using   the   lens   to   create   a   virtual   image   of   the   object   at   (or   close   to   )   infinity.   the   diagram   below   shows   the   basic parameters of the eyepiece in terms of
Field of View : Eye Relief : Eye Box :
 If the eyelens of the Ramsden lens is achromatized, then it becomes a Kellner Eyepiece, which has reduced lateral colour. As can be seen form the diagram, the Plossl Eyepiece consists of two achromatic elements (which may be identical). The crown element of the doublets face inwards towards each other.  The Plossl has greater eye relief than the Kellner eyepiece, although it may suffer with some distortion. the typical field of view for this type of eyepiece is around 50 degrees full field.
Below   is   a   small   selection   of   the   many   Eyepiece   Lens   design   types   which   show   the   varying   amount   of   lens   elements   and   the   overall   form   of   each lens. A brief description of the lens type is given for each lens. Should you require any help with lenses for imaging applications, please get in touch with us at design@optovise.com
The Ramsden Eyepiece consists of two plan-convex elements, with the plane face of the eye lens facing the eye, and the plane face of the field lens facing away from the eye. The Ramsden has an external focal plane, which would allow for a graticule to be imaged at the focal plane. The field of view is limited with this type of eyepiece, as is the eye relief |OptoVise Ltd, Midlothian Innovation Centre, Roslin, Edinburgh, EH25 9RE | |Tel : +44(0) 131 2080719  | email : design@optovise.com |

+44 (0) 131 2080719

design@optovise.com