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US 2003/0223129 A1Published application
Hybrid lens system
AssigneeLargan Precision Co., Ltd.
InventorYeo-Chih Huang
Life of this patent
Estimating the term…
Abstract
A lens system includes a plastic positive lens, a plastic negative lens and a glass positive lens. The plastic lenses are made to be meniscus lenses and an aspheric surface and a diffractive surface are respectively mounted onto the plastic lenses so as to have better image with low manufacturing cost.
Claims10
A lens system comprising:
- three lenses juxtaposed with each other and each having refractive power, a first one of the three lenses serving with positive refractive power being a plastic lens having a front side formed with a convex surface having a radius of curvature of R1 and a rear side formed with a concave surface having a radius of curvature of R2, |R1|<|R2|;
- a second one of the three lenses serving with negative refractive power being a plastic lens having a front side formed with a concave surface, a shape of coefficient X2 ((R1+R2)/(R2−R1)) being larger than 0.9;
- a third one of the three lenses serving with positive refractive power being a glass lens having positive refractive power;
- the shape coefficient of a lens being defined as X=(R1+R2)/(R2−R1), wherein R1 being the radius of curvature of front surface of lens, R2 being the radius of curvature of the rear surface of lens, and R1>0 as the front surface being convex, R1<0 as the front surface being concave, R2<0 as the rear surface being convex, R2>0 as the rear surface being concave;
- at least one diffractive surface being formed on the plastic lens of the three lenses, and
- at least one aspheric surface being formed on the plastic lens of the three lenses.
3 more elements
A lens system comprising:
- three lenses juxtaposed with each other and each having refractive power, wherein
- a first one of the three lenses serving with positive refractive power being a glass lens;
- a second one of the three lenses serving with negative refractive power being a plastic lens and having a rear side formed with a concave surface and a shape coefficient X2 being smaller than −0.9:
- a third one of the three lenses serving as positive power being a plastic lens and having a front side formed with a concave surface and a rear side formed with a convex surface, and the shape coefficient X3 being located with a range between −1.0 to −20:
- at least one diffractive surface being formed on the plastic lenses of the three lenses;
- and
- at least one aspheric surface being formed on the plastic lenses of the three lenses.
4 more elements
Dependencies are inferred from the claim text.