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US 2010/0149655 A1Published application
Projection-use zoom lens
AssigneeBrother Kogyo Kabushiki Kaisha
InventorsTakeshi Kitakata, Takahiro Sugiyama
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AssigneeBrother Kogyo Kabushiki Kaisha
InventorsTakeshi Kitakata, Takahiro Sugiyama
Estimating the term…
The present invention provides a zoom lens having fewer constituting lenses and capable of easily keeping telecentricity. From a projection plane side, lens groups ranging from a first lens group to a fourth lens group are disposed, sequentially. The first lens group consists of the three lenses, one negative lens, one positive lens and one negative lens arranged sequentially from the projection plane side, and has a negative power. The second lens group consists of three lenses in total, that is, one positive lens, one compound lens and one compound lens arranged sequentially from the projection plane PL side and has a positive power. The third lens group consists of one negative lens. The fourth lens group consists of one positive lens. At power varying, the first lens group and the second lens group are moved with the third lens group and the fourth lens group kept fixed. The third lens group is moved for focusing.
A zoom lens capable of varying power between a short focal end and a long focal end thereof, the zoom lens comprising a first lens group, a second lens group, a third lens group and a fourth lens group arranged sequentially from a projection plane side, wherein
A zoom lens capable of varying power between a short focal end and a long focal end thereof, the zoom lens comprising a first lens group, a second lens group and a third lens group arranged sequentially from a projection plane side, wherein
Dependencies are inferred from the claim text.