PROJECTION LENS

Japanese Patent JP3921160

B2

PROBLEM TO BE SOLVED: To provide a small and light-weight projection lens in which brightness is obtained at a wide viewing angle so that a projection viewing angle is about 75° and an f-number is about 2.4, lateral chromatic aberration and distortion aberration are excellently corrected, optical stability in environmental change is excellent and which is suitable to enlarge and project a high-definition image.
SOLUTION: The projection lens has a 1st lens group having negative refractive power, a 2nd lens group having positive refractive power and a 3rd lens group having positive refractive power in order from an enlargement side, and the 1st lens group includes one or more aspherical lenses, at least either surface of which is formed as an aspherical surface, and the 2nd lens group includes at least one positive lens and the 3rd lens group includes at least one doublet obtained by bonding three lenses, a positive lens, a negative lens and a positive lens in this order. In such an optical system, (1) 0.9≤|f1|/f≤1.4 (2) 2.1≤f2/f≤ 3.4 and (3) 1.9≤f3/f≤2.8 are satisfied.

JP2011081072	PROJECTION LENS FOR SMALL PROJECTOR
JPWO2003007046	An optical system and an exposure device equipped with the optical system
JP5217693	Lens system and optical device

Yasuharu Yamada

JP2002291122A

May 30, 2007

October 03, 2002

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Tamron Co., Ltd.

G02B13/24; G02B9/12; G02B13/04; G02B13/18; (IPC1-7): G02B13/24; G02B13/04; G02B13/18

JP11326755A
JP5329120A
JP2002131636A
JP10260346A

Minoru Nakamura
Fumiaki Otsuka
Sadao Kumakura
Shishido Kaichi
Nobuo Ogawa
Village shrine Atsuo
Takaki Nishijima
Atsushi Hakoda

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