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US-12625350-B2 - Optical imaging system

US12625350B2US 12625350 B2US12625350 B2US 12625350B2US-12625350-B2

Abstract

There is provided an optical imaging system including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens includes a negative refractive power and a concave object-side surface. The second lens includes a concave object-side surface. The fourth lens includes a negative refractive power. The sixth lens includes an inflection point formed on an image-side surface thereof. The first to sixth lenses are sequentially disposed from an object side toward an imaging plane.

Inventors

  • Tae Youn LEE

Assignees

  • SAMSUNG ELECTRO-MECHANICS CO., LTD.

Dates

Publication Date
20260512
Application Date
20240606
Priority Date
20151019

Claims (10)

  1. 1 . An optical imaging system, comprising: a first lens comprising a refractive power, and a concave object-side surface; a second lens comprising a refractive power; a third lens comprising a refractive power; a fourth lens comprising a refractive power, and a convex object-side surface; a fifth lens comprising a refractive power; and a sixth lens comprising a refractive power, wherein the first to sixth lenses are sequentially disposed from an object side toward an imaging plane, wherein an absolute value of a radius of curvature of an object-side surface of the fourth lens is greater than an absolute value of a radius of curvature of the object-side surface of the first lens, and wherein −5.5<(R1+R2)/(R1−R2)<0.5, where R1 is a radius of curvature of an object-side surface of the first lens and R2 is a radius of curvature of an image-side surface of the first lens.
  2. 2 . The optical imaging system of claim 1 , wherein the second lens has a concave object-side surface.
  3. 3 . The optical imaging system of claim 1 , wherein the third lens has a convex object-side surface.
  4. 4 . The optical imaging system of claim 1 , wherein the fifth lens has a convex object-side surface.
  5. 5 . The optical imaging system of claim 1 , wherein the sixth lens has a convex object-side surface.
  6. 6 . The optical imaging system of claim 1 , wherein the sixth lens has a n inflection point formed on an image-side surface thereof.
  7. 7 . An optical imaging system, comprising: a first lens comprising a refractive power, and a concave object-side surface; a second lens comprising a refractive power; a third lens comprising a refractive power and a convex image-side surface; a fourth lens comprising a refractive power, and a convex object-side surface; a fifth lens comprising positive refractive power; and a sixth lens comprising a refractive power, wherein the first to sixth lenses are sequentially disposed from an object side toward an imaging plane, and wherein an absolute value of a radius of curvature of an object-side surface of the fourth lens is greater than an absolute value of a radius of curvature of the object-side surface of the first lens.
  8. 8 . The optical imaging system of claim 7 , wherein the third lens has a convex object-side surface.
  9. 9 . The optical imaging system of claim 7 , wherein the fifth lens has a convex object-side surface.
  10. 10 . The optical imaging system of claim 7 , wherein the sixth lens has a convex object-side surface.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a Continuation Application of U.S. patent application Ser. No. 18/080,333, filed on Dec. 13, 2022, which is a Continuation Application of U.S. patent application Ser. No. 16/848,152, filed on Apr. 14, 2020, now U.S. Pat. No. 11,550,126 issued on Jan. 10, 2023, which is a Continuation Application of U.S. patent application Ser. No. 16/502,485, now U.S. Pat. No. 10,656,394, filed on Jul. 3, 2019, which is a continuation of U.S. patent application Ser. No. 15/887,253, now U.S. Pat. No. 10,386,612, filed on Feb. 2, 2018, which is a divisional of U.S. patent application Ser. No. 15/187,918 filed on Jun. 21, 2016, now U.S. Pat. No. 9,952,409, which claims the benefit under 35 USC § 119 (a) of Korean Patent Application No. 10-2015-0145260 filed on Oct. 19, 2015, in the Korean Intellectual Property Office, the entire disclosures of each of which are incorporated herein by reference for all purposes. BACKGROUND 1. Field The following description relates to an optical imaging system including lenses. 2. Description of Related Art A plurality of optical imaging systems may be mounted in a portable terminal. For example, optical imaging systems may be mounted on each of a front surface and a rear surface of the portable terminal. The optical imaging system mounted on the rear surface of the portable terminal may be used to image a subject located at a relatively long distance. On the other hand, the optical imaging system mounted on the front surface of the portable terminal is used to image a subject located at a relatively short distance. However, the optical imaging system mounted on the front surface of the portable terminal may generate an optical distortion phenomenon, such as “cone-head.” Therefore, there is a need to develop an optical imaging system capable of reducing optical distortions, such as “cone-head” distortions, and being appropriate for imaging a subject at a relatively short distance. SUMMARY This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. In accordance with an embodiment, there is provided an optical imaging system, including: a first lens including a negative refractive power and a concave object-side surface; a second lens including a concave object-side surface; a third lens; a fourth lens including a negative refractive power; a fifth lens; and a sixth lens including an inflection point formed on an image-side surface thereof, wherein the first to sixth lenses are sequentially disposed from an object side toward an imaging plane. The second lens may include a positive refractive power. The third lens may include a positive refractive power. The fifth lens may include a positive refractive power. The sixth lens may include a negative refractive power. −35.0<{(1/f)*(Y/tan θ)−1}*100<−5.0, in which f may be an overall focal length of the optical imaging system, Y may be ½ of a diagonal length of the imaging plane, and 0 may be equal to half a field of view of the optical imaging system. TL/2Y<0.95, in which TL may be a distance from the object-side surface of the first lens to the imaging plane, and 2Y may be a diagonal length of the imaging plane. R1/f<−0.5, in which f may be an overall focal length of the optical imaging system, and R1 may be a radius of curvature of the object-side surface of the first lens. −5.5<(R1+R2)/(R1−R2)<0.5, in which R1 may be a radius of curvature of the object-side surface of the first lens, and R2 may be a radius of curvature of an image-side surface of the first lens. −1.5<f/f1<−0.05, in which f may be an overall focal length of the optical imaging system, and f1 may be a focal length of the first lens. 0.5<f/f3<2.0, in which f may be an overall focal length of the optical imaging system, and f3 may be a focal length of the third lens. 0.7<|f/f6|<1.8, in which f may be an overall focal length of the optical imaging system, and f6 may be a focal length of the sixth lens. 1.5<f/EPD<2.1, in which f may be an overall focal length of the optical imaging system, and EPD may be an entrance pupil diameter of the optical imaging system. 0.4<(t1+t2)/t3<1.3, in which t1 may be a thickness at an optical axis center of the first lens, t2 may be a thickness at an optical axis center of the second lens, and t3 may be a thickness at an optical axis center of the third lens. 0<|n1−n2|<0.25, in which n1 may be a refractive index of the first lens, and n2 may be a refractive index of the second lens. In accordance with an embodiment, there is provided an optical imaging system, including: a first lens including a concave object-side surface; a second lens including a convex image-side surface; a third lens having including a convex