Optical imaging system

Patent metadata

Field	Value
Publication number	US-11960058-B2
Application number	US-202318299984-A
Country	US
Kind code	B2
Filing date	Apr 13, 2023
Priority date	Aug 21, 2017
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side toward an image side on an optical axis, and a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses. The first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis, and 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of an image sensor, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane of the image sensor.

First claim

What is claimed is:

1. An optical imaging system comprising:
a first lens having positive refractive power and a convex object-side surface;
a second lens having negative refractive power, a convex object-side surface and a concave image-side surface;
a third lens having refractive power;
a fourth lens having positive refractive power, and
wherein the first to fourth lenses are sequentially disposed from an object side toward an image side on an optical axis,
wherein the optical imaging system has a total of four lenses,
wherein 1.3<TTL/BFL<3.5 is satisfied, where TTL is a distance from the object-side surface of the first lens to an imaging plane, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane, and
wherein FOV≤40° is satisfied, where FOV is a field of view of the optical imaging system.

2. The optical imaging system of claim 1 , wherein 0.8<TTL/f<1.5 is satisfied, where f is an overall focal length of an optical imaging system.

3. The optical imaging system of claim 1 , wherein the first lens has a convex image-side surface.

4. The optical imaging system of claim 1 , wherein the third lens has a convex image-side surface.

5. The optical imaging system of claim 1 , wherein the fourth lens has a convex object-side surface.

6. The optical imaging system of claim 5 , wherein the fourth lens has a concave image-side surface.

7. The optical imaging system of claim 1 , wherein the first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis.

8. The optical imaging system of claim 1 , wherein the first to fourth lenses are formed of plastic materials.

9. The optical imaging system of claim 8 , wherein the first lens comprises a first plastic material, and
the second lens and the third lens comprise plastic materials comprising optical characteristics different from those of the first plastic material.

10. The optical imaging system of claim 9 , wherein the plastic material of the second lens comprises optical characteristics different from the plastic material of the third lens.

11. The optical imaging system of claim 1 , further comprising a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses.

12. The optical imaging system of claim 1 , wherein 0.9<DF/DC<1.3 is satisfied, where DF is an effective aperture radius of an image-side surface of the fourth lens, and DC is an effective aperture radius of the object-side surface of the first lens.

Assignees

• Samsung Electro Mech

Inventors

• Yoo Ho Sik
• Yang Dong Shin
• Jo Yong Joo
• Seo Sot Eum

Classifications

• G02B13/004 Primary

  having four lenses · CPC title

• G02B9/38

  both - components being meniscus · CPC title

• G02B9/50

  both + components being meniscus · CPC title

• G02B9/56

  all components being simple lenses · CPC title

• G02B13/0065

  having a beam-folding prism or mirror · CPC title