Optical: systems and elements – Lens – Telecentric system
Patent
1997-07-25
1999-07-06
Epps, Georgia
Optical: systems and elements
Lens
Telecentric system
359649, 359754, G02B 1322
Patent
active
059204338
ABSTRACT:
A projection lens, which is as fast as 1.5 or thereabout in F-number and has an excellent telecentric property, includes, in order from a screen side, a first lens unit having a positive refractive power in a retrofocus form and a second lens unit. The first lens unit includes, in order from the screen side, at least two negative meniscus lenses convex toward the screen side, a positive lens having a refractive power on the screen side which is stronger than that of an opposite surface thereof, a positive lens having a refractive power on an image generating plane side which is stronger than that of an opposite surface thereof, a cemented lens composed of a negative lens and a positive lens and having a cemented surface convex toward the screen side, and at least one positive lens. The second lens unit includes, in order from the screen side, at least one positive lens and a negative lens having a refractive power on the screen side which is stronger than that of an opposite surface thereof.
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Canon Kabushiki Kaisha
Epps Georgia
Schwartz Jordan M.
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