| 摘要 |
<p>PURPOSE: To provide a projection lens system for back projection-type TV, which can secure a bright picture and a sufficient picture angle and which can easily adjust a color aberration by reducing the number of required lenses compared to a conventional system. CONSTITUTION: The projection lens system for back projection-type TV, which has the multiple lenses arranged in series along an optical axis vertical to a CRT screen, is provided with a first lens L1 whose one face has a spherical surface, whose center part hardly has optical power and whose peripheral part has weak positive optical power, a second lens L2 which has strong positive optical power lens, whose one face has the non-spherical surface and whose both faces have projection forms, a third lens L3 which has strong negative optical power, whose one face has the non-spherical surface and whose both faces have recessed forms, a fourth lens L4 which has strong positive optical power, whose one face has the non-spherical surface and whose both faces have projection forms and a fifth lens L5 which has weak negative optical power, whose one face has the non-spherical surface and which has a new moon form are provided.</p> |
