Imaging lens system
DC CAFCFirst Claim
1. An imaging lens system comprising, in order from an object side to an image side:
- a first lens element with positive refractive power having a convex object-side surface;
a second lens element with negative refractive power;
a third lens element with positive refractive power, at least one of the object-side and image-side surfaces thereof being aspheric;
a fourth lens element, the image-side surface thereof being aspheric and provided with at least one inflection point;
a fifth lens element having a concave object-side surface, at least one of the object-side and image-side surfaces thereof being aspheric; and
an aperture stop disposed between an imaged object and the second lens element.
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Abstract
The present invention provides an imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element with positive refractive power, at least one of the object-side and image-side surfaces thereof being aspheric; a fourth lens element, the image-side surface thereof being aspheric and provided with at least one inflection point; a fifth lens element having a concave object-side surface, at least one of the object-side and image-side surfaces thereof being aspheric; and an aperture stop disposed between an imaged object and the second lens element. Such an arrangement of optical elements can effectively reduce the total track length and sensitivity of the optical system, and image quality can also be improved.
127 Citations
20 Claims
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1. An imaging lens system comprising, in order from an object side to an image side:
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a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element with positive refractive power, at least one of the object-side and image-side surfaces thereof being aspheric; a fourth lens element, the image-side surface thereof being aspheric and provided with at least one inflection point; a fifth lens element having a concave object-side surface, at least one of the object-side and image-side surfaces thereof being aspheric; and an aperture stop disposed between an imaged object and the second lens element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An imaging lens system comprising, in order from an object side to an image side:
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a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element with positive refractive power; a fourth lens element with positive or negative refractive power, the image-side surface thereof being aspheric and provided with at least one inflection point; and a fifth lens element with positive or negative refractive power having a concave object-side surface, at least one of the object-side and image-side surfaces thereof being aspheric; wherein the focal length of the first lens element is f1, the focal length of the third lens element is f3, and they satisfy the relation;
0<
f1/f3<
1.2;wherein the curvature radius of the object-side surface of the first lens element is R1, the focal length of the imaging lens system is f, and they satisfy the relation;
0.30<
R1/f<
0.50;wherein the Abbe number of the first lens element is V1, the Abbe number of the second lens element is V2, and they satisfy the relation;
22.0<
V1−
V2; andwherein the lens elements with refractive power are limited to the first, second, third, fourth, and fifth lens elements.
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20. An imaging lens system comprising, in order from an object side to an image side:
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a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element with positive or negative refractive power; a fourth lens element with positive or negative refractive power, the image-side surface thereof being aspheric and provided with at least one inflection point; and a fifth lens element with positive or negative refractive power having a concave object-side surface, at least one of the object-side and image-side surfaces thereof being aspheric; wherein the focal length of the imaging lens system is f, the focal length of the third lens element is f3, and they satisfy the relation;
0.2<
|f/f3|;wherein the curvature radius of the object-side surface of the first lens element is R1, the focal length of the imaging lens system is f, and they satisfy the relation;
0.30<
R1/f<
0.50;wherein the Abbe number of the first lens element is V1, the Abbe number of the second lens element is V2, and they satisfy the relation;
22.0<
V1−
V2; andwherein the lens elements with refractive power are limited to the first, second, third, fourth, and fifth lens elements.
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Specification