Optical imaging system, image capturing unit and electronic device
AssigneeLargan Precision Co., Ltd.
InventorsYu-Tai Tseng, Hsin-Hsuan Huang
Life of this patent
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Abstract
An optical imaging system includes four lens elements which are, in order from an object side to an image side: a first lens element, a second lens element, a third lens element and a fourth lens element. Each of the four lens elements of the optical imaging system has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The object-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex shape in an off-axis region thereof. The object-side surface of the first lens element is aspheric. The image-side surface of the fourth lens element is concave in a paraxial region thereof. The optical imaging system has a total of four lens elements.
Claims30
An optical imaging system comprising four lens elements, the four lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element;
- each of the four lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;
- wherein the first lens element has negative refractive power, the object-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex shape in an off-axis region thereof, the object-side surface of the first lens element is aspheric, the third lens element has positive refractive power, the fourth lens element has negative refractive power, and a total number of lens elements in the optical imaging system is four;
- wherein the optical imaging system further comprises an aperture stop, an axial distance between the object-side surface of the first lens element and an image surface is TL, a focal length of the optical imaging system is f, an axial distance between the aperture stop and the image-side surface of the fourth lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the fourth lens element is TD, an Abbe number of the fourth lens element is V4, and the following conditions are satisfied:
- 3.51
- ≤
- T
-
- L
- /
- f
- <
- 1
-
- 0.0
- ;
- 0.3
-
- 4
- <
- S
-
- D
- /
- T
-
- D
- ≤
- 0
-
- .58
- ;
- 1
-
- 0
- .
- 0
- <
- V
-
- 4
- <
- 23.0
- ;
- and
- 0.50
-
-
- mm
- <
- TL
- <
- 4.0
-
-
- mm
- .
An optical imaging system comprising four lens elements, the four lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element;
- each of the four lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;
- wherein a total number of lens elements in the optical imaging system is four, the first lens element has negative refractive power, the third lens element has positive refractive power, the fourth lens element has negative refractive power, and the object-side surface of the fourth lens element is concave in a paraxial region thereof;
- wherein an axial distance between the object-side surface of the first lens element and an image surface is TL, a focal length of the optical imaging system is f, a curvature radius of the object-side surface of the first lens element is R1, a curvature radius of the image-side surface of the first lens element is R2, a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of the image-side surface of the second lens element is R4, a minimum value among Abbe numbers of all lens elements of the optical imaging system is Vmin, a central thickness of the first lens element is CT1, a central thickness of the third lens element is CT3, and the following conditions are satisfied:
- 4
- .
- 1
-
- 5
- ≤
- T
-
- L
- /
- f
- <
- 1
-
- 0.0
- ;
-
- -
- 1
-
- 0
- .
- 0
- <
- (
- R
-
- 1
- +
- R
-
- 2
- )
- /
- (
- R
-
-
- 1
- -
- R
-
-
- 2
- )
- <
- 0
-
- .50
- ;
-
- -
- 0.
-
- 4
-
- 5
- <
- (
- R
-
-
- 3
- -
- R
-
-
- 4
- )
- /
- (
- R
-
- 3
- +
- R
-
- 4
- )
- <
- 0
-
- .65
- ;
- 1
-
- 0
-
- .0
- <
- V
-
-
- min
- <
- 20.5
- ;
- and
- CT
-
-
- 1
- <
- CT
-
- 3
- .
An optical imaging system comprising four lens elements, the four lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element;
- each of the four lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;
- wherein the first lens element has negative refractive power, the object-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex shape in an off-axis region thereof, the object-side surface of the first lens element is aspheric, the image-side surface of the first lens element is concave in a paraxial region thereof, the third lens element has positive refractive power, the object-side surface of the third lens element is convex in a paraxial region thereof, the fourth lens element has negative refractive power, the object-side surface of the fourth lens element is concave in a paraxial region thereof, the image-side surface of the fourth lens element is concave in a paraxial region thereof, and a total number of lens elements in the optical imaging system is four;
- wherein a focal length of the optical imaging system is f, an entrance pupil diameter of the optical imaging system is EPD, a curvature radius of the object-side surface of the first lens element is R1, a curvature radius of the image-side surface of the first lens element is R2, an Abbe number of the fourth lens element is V4, and the following conditions are satisfied:
- 1
- .
- 0
- <
- f
- /
- EPD
- <
- 2
-
- .25
- ;
-
- -
- 1
-
- 0
- .
- 0
- <
- (
- R
-
- 1
- +
- R
-
- 2
- )
- /
- (
- R
-
-
- 1
- -
- R
-
-
- 2
- )
- <
- 0.50
- ;
- and
- 1
-
- 0
- .
- 0
- <
- V
-
- 4
- <
- 2
-
- 3
- .
- 0
- .
An optical imaging system comprising four lens elements, the four lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element;
- each of the four lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;
- wherein the first lens element has negative refractive power, the object-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex shape in an off-axis region thereof, the object-side surface of the first lens element is aspheric, the third lens element has positive refractive power, the fourth lens element has negative refractive power, the object-side surface of the fourth lens element is concave in a paraxial region thereof, the image-side surface of the fourth lens element is concave in a paraxial region thereof, a central thickness of the second lens element is larger than an axial distance between the third lens element and the fourth lens element, and a total number of lens elements in the optical imaging system is four;
- wherein a focal length of the optical imaging system is f, an entrance pupil diameter of the optical imaging system is EPD, and the following condition is satisfied:
- 1
- .
- 0
- <
- f
- /
- EPD
- <
- 2
- .
- 2
-
- 5
- .
Dependencies are inferred from the claim text.