Lens system with small emergence angle
AssigneeHon Hai Precision Industry Co., Ltd.
InventorsKuo-Yen Liang, Chun-Hsiang Huang
Life of this patent
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Abstract
A lens system includes a positive refractive power first lens, a negative refractive power second lens, a positive refractive power third lens, and a negative refractive power fourth lens in that order from the object side of the lens system. Wherein the lens system satisfies the following conditions: (1) D1/D2<1.6; and (2) R2/F1>1.8, wherein, D1 is the effective radius of a surface of the third lens facing the image side of the lens system, D2 is a distance from the top point of a surface to the optical center of the third lens, R2 is the radius of curvature of a surface of the first lens facing the image side of the lens system, and F1 is a focal length of the first lens.
Claims8
A lens system comprising, in order from the object side:
- a positive refractive power first lens;
- a negative refractive power second lens;
- a positive refractive power third lens;
- and
- a negative refractive power fourth lens,
- wherein the lens system satisfies the following conditions:
- D1/D2<1.6;
- and (1)
- R2/F1>1.8, (2)
- wherein, D1 is the effective radius of a surface of the third lens facing the image side of the lens system, D2 is a distance from the top point of a surface to the optical center of the third lens, R2 is the radius of curvature of a surface of the first lens facing the image side of the lens system, and F1 is a focal length of the first lens.
Dependencies are inferred from the claim text.