US-20260126623-A1 - OPTICAL SYSTEM AND CAMERA MODULE COMPRISING SAME

US20260126623A1US 20260126623 A1US20260126623 A1US 20260126623A1US-20260126623-A1

Abstract

The optical system disclosed in the embodiment includes first to ninth lenses aligned from the object side toward the sensor side, the first lens has a positive refractive power on the optical axis, and the ninth lens has negative refractive power on the optical axis, an object-side surface of the first lens has a convex shape on the optical axis, a sensor-side surface of the ninth lens has a concave shape on the optical axis, and a number of lenses having at least one critical point on object-side surfaces and a sensor-side surfaces among the first to ninth lenses is 40% or more of a total number of lenses, and the following equations are satisfied, Equations: −1.5<f12/f39<1.7 and 0.6<TTL/ImgH<3.2 (f12 is a composite focal length of the first and second lenses, f39 is a composite focal length of the third to ninth lenses, and TTL (Total track length) is a distance from an apex of the object-side surface of the first lens to an upper surface of the image sensor on the optical axis, and ImgH is ½ of the maximum diagonal length of the image sensor).

Inventors

Young Hwan Choi

Assignees

LG INNOTEK CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20221027
Priority Date: 20211029

Claims (20)

1 . An optical system comprising: first to ninth lenses disposed along an optical axis in a direction from an object side to a sensor side, wherein the first lens has a positive (+) refractive power on the optical axis, wherein the ninth lens has a negative (−) refractive power on the optical axis, wherein an object-side surface of the first lens has a convex shape on the optical axis, wherein a sensor-side surface of the ninth lens has a concave shape on the optical axis, wherein a number of lenses having at least one critical point on object-side surfaces and sensor-side surfaces among the first to ninth lenses is 40% or more of a total number of lenses, and wherein the optical system satisfies the following equations, - 1 . 5 < f ⁢ 12 / f ⁢ 39 < 1.7 Equations 0.6 < TTL / ImgH < 3.2 (f12 is a composite focal length of the first and second lenses, f39 is a composite focal length of the third to ninth lenses, and TTL (Total track length) is a distance from an apex of the object-side surface of the first lens to an upper surface of an image sensor on the optical axis, and ImgH is ½ of a maximum diagonal length of the image sensor).
2 . The optical system of claim 1 , wherein the object-side surface of the first lens has a convex shape, wherein the sensor-side surface of the ninth lens has a concave shape, and wherein each of object-side surfaces and sensor-side surfaces of the sixth to ninth lenses has at least one critical point.
3 . The optical system of claim 2 , wherein the sensor-side surface of the first lens and an object-side surface of the fourth lens have at least one critical point, and wherein an object-side surface and a sensor-side surface of the third lens have at least one critical point.
4 . The optical system of claim 1 , wherein a relationship between a distance BFL on the optical axis from the upper surface of the image sensor to a sensor-side surface of a last lens and ImgH satisfies the following equation, 0 . 0 ⁢ 1 < BFL / ImgH < 0.5 . Equation
5 . The optical system of claim 1 , wherein a relationship between effective diameters of the first lens and the ninth lens and a total number of lenses satisfies the following equation, 1 < ∑ CA / lens ⁢ number < 10 Equation (ΣCA is a sum of the effective diameters of object-side surfaces and sensor-side surfaces of the first to ninth lenses, and the lens number is the total number of lenses).
6 . The optical system of claim 1 , wherein a relationship between a total focal length and a focal length of each lens satisfies the following equation, 1 . 5 < Σ ⁢ ❘ "\[LeftBracketingBar]" F / fi ❘ "\[RightBracketingBar]" < 20 Equation (F is the total focal length, and fi is a sum of focal lengths of the first to ninth lenses).
7 . The optical system of claim 1 , wherein distances on the optical axis between the first to ninth lenses and center thicknesses of each lens satisfy the following equation, 0 .8 < Air_CT ⁢ _Max / L_CT ⁢ _Min < 6 . 0 Equation (Air_CT_Max is a maximum value among the distances on the optical axis between two adjacent lenses, and L_CT_Min is a minimum value among the thicknesses of each lens on the optical axis).
8 . The optical system of claim 1 , wherein a relationship between a maximum effective diameter and a minimum effective diameter among the first to ninth lenses satisfies the following equation, 1 < CA_Max / CA_Min < 4 Equation (CA_Max is a maximum value among effective diameters of object-side surfaces and sensor-side surfaces of the first to ninth lenses, and CA_Min is a minimum value among the effective diameters of the object-side surfaces and the sensor-side surfaces of the first to ninth lenses).
9 . The optical system of claim 8 , wherein the sensor-side surface of the second lens has a concave shape on the optical axis, wherein the object-side surface of the third lens faces the sensor-side surface of the second lens and has a convex shape on the optical axis, wherein the maximum effective diameter is the sensor-side surface of the ninth lens, and wherein the minimum effective diameter is the object-side surface of the third lens.
10 . The optical system of claim 9 , wherein a center thickness of the first lens and the third lens satisfies the following equation, 1 < L1_CT / L3_CT < 5 Equation (L1_CT is the thickness on the optical axis of the first lens, and L3_CT is the thickness on the optical axis of the third lens).
11 . The optical system of claim 1 , comprising an aperture stop disposed on an outer periphery between the second lens and the third lens, wherein a relationship between effective radii of the first to ninth lenses and an effective radius of the aperture stop satisfies the following equation, 1 . 5 < ΣSemi_CA / ST_Semi ⁢ _CA < 5 ⁢ 0 Equation (ΣSemi_CA is a sum of all effective radii, and ST_Semi_CA is the effective radius of the aperture stop).
12 . The optical system of claim 1 , wherein a relationship between effective diameters of the first to ninth lenses and the total number of lenses satisfies the following equation, 1 < ∑ CA / lens ⁢ number < 10 Equation (ΣCA is a sum of the effective diameters of object-side surfaces and sensor-side surfaces of the first to ninth lenses, and the lens number is 9).
13 . An optical system comprising: a first lens group having a plurality of lenses on an object side; and a second lens group having a plurality of lenses on a sensor side of the first lens group, wherein the first lens group has a positive (+) refractive power on an optical axis, wherein the second lens group has a positive (+) refractive power on the optical axis, wherein a number of lenses in the second lens group is three times or more than a number of lenses in the first lens group, wherein an object-side surface closest to the first lens group in the second lens group has a smallest effective diameter, wherein a sensor-side surface closest to an image sensor among lens surfaces of the second lens group has a largest effective diameter, wherein the sensor-side surface closest to the image sensor among the lens surfaces of the second lens group has a minimum distance between a center of the sensor-side surface and the image sensor, and the distance gradually increases toward an end of an effective region of the sensor-side surface, and wherein the optical system satisfies the following equations, 0 . 6 < TTL / ImgH < 3.2 Equations 0.6 < TTL / ImgH < 3.2 0.7 < F / EPD < 2 . 6 (Total track length (TTL) is a distance on the optical axis from an apex of an object-side surface of the first lens group to an upper surface of the image sensor, ImgH is ½ of a maximum diagonal length of the image sensor, and F is a total focal length of the first and second lens groups, and EPD is a size of an entrance pupil diameter of the optical system).
14 . The optical system of claim 13 , wherein a focal length of each of the first and second lens groups is greater in the first lens group than in the second lens group.
15 . The optical system of claim 13 , wherein the first lens group comprises a first lens and a second lens aligned with the optical axis from the object side toward the image sensor, wherein the second lens group includes third to ninth lenses aligned from the first lens group toward the image sensor, wherein an average effective diameter of the third lens is a smallest among that of the first to ninth lenses, and wherein an average effective diameter of the ninth lens is a largest that of the first to ninth lenses.
16 . The optical system of claim 15 , wherein a sensor-side surface of the ninth lens has a critical point and satisfies the following equation, 0 .5 < L9S2_max ⁢ _sag ⁢ to ⁢ Sensor < 2 Equation (L9S2_max_sag to Sensor is a distance in a direction of the optical axis from a maximum Sag value of the sensor-side surface of the ninth lens to the image sensor).
17 . The optical system of claim 15 , wherein a number of lenses having critical points on both object-side surfaces and sensor-side surfaces in the second lens group is 50% or more of lenses in the second lens group, and wherein a thickness of the first lens on the optical axis and a distance between the first and second lenses satisfy the following equation, 2 ⁢ 0 < L1_CT / d ⁢ 12 Equation (L1_CT is the thickness on the optical axis of the first lens, and d12 is the distance on the optical axis between the first and second lenses).
18 . (canceled)
19 . The optical system of claim 18 , wherein a distance between the eighth lens and the ninth lens satisfies the following equation, 0 < d89_CT / d89_ET < 3 Equation (d89_CT is a distance on the optical axis between the eighth lens and the ninth lens, and d89_ET is a distance on the optical axis between an end of an effective region of a sensor-side surface of the eighth lens and an end of an effective region of an object-side surface of the ninth lens).
20 . The optical system of claim 13 , wherein a focal length f_G1 of the first lens group and a focal length f_G2 of the second lens group satisfy the following equation, - 1.5 < f_G1 / f_G2 < 1 . 7 . Equation

Description

TECHNICAL FIELD An embodiment relates to an optical system for improved optical performance and a camera module including the same. BACKGROUND ART The camera module captures an object and stores it as an image or video, and is installed in various applications. In particular, the camera module is produced in a very small size and is applied to not only portable devices such as smartphones, tablet PCs, and laptops, but also drones and vehicles to provide various functions. For example, the optical system of the camera module may include an imaging lens for forming an image, and an image sensor for converting the formed image into an electrical signal. In this case, the camera module may perform an autofocus (AF) function of aligning the focal lengths of the lenses by automatically adjusting the distance between the image sensor and the imaging lens, and may perform a zooning function of zooming up or zooning out by increasing or decreasing the magnification of a remote object through a zoom lens. In addition, the camera module employs an image stabilization (IS) technology to correct or prevent image stabilization due to an unstable fixing device or a camera movement caused by a user's movement. The most important element for this camera module to obtain an image is an imaging lens that forms an image. Recently, interest in high efficiency such as high image quality and high resolution is increasing, and research on an optical system including plurality of lenses is being conducted in order to realize this. For example, research using a plurality of imaging lenses having positive (+) and/or negative (−) refractive power to implement a high-efficiency optical system is being conducted. However, when a plurality of lenses is included, there is a problem in that it is difficult to derive excellent optical properties and aberration properties. In addition, when a plurality of lenses is included, the overall length, height, etc. may increase due to the thickness, interval, size, etc. of the plurality of lenses, thereby increasing the overall size of the module including the plurality of lenses. In addition, the size of the image sensor is increasing to realize high resolution and high quality. However, when the size of the image sensor is increased, a total track length (TTL) of the optical system including the plurality of lenses also increases, and thus there is a problem in that the thickness of the camera and the mobile terminal including the optical system also increases. Therefore, a new optical system capable of solving the above problems is required. DISCLOSURE Technical Problem An embodiment provides an optical system with improved optical properties. An embodiment provides an optical system having excellent optical performance on the center and periphery portions of the angle of field of view. An embodiment provides an optical system capable of having a slim structure. Technical Solution An optical system according to an embodiment of the invention includes first to ninth lenses disposed along an optical axis from an object side toward a sensor side, wherein the first lens has a positive (+) refractive power on the optical axis, and the ninth lens has a negative (−) refractive power on the optical axis, an object-side surface of the first lens has a convex shape on the optical axis, and a sensor-side surface of the ninth lens has a concave shape on the optical axis, a number of lenses having at least one critical point on object-side surfaces and a sensor-side surfaces among the first to ninth lenses is 40% or more of a total number of lenses, and the following equations are satisfied, -1.5<f⁢12/f⁢39<1.7Equations0.6<TTL/ImgH<3.2(f12 is a composite focal length of the first and second lenses, f39 is a composite focal length of the third to ninth lenses, and TTL (Total track length) is a distance from an apex of the object-side surface of the first lens to an upper surface of the image sensor on the optical axis, and ImgH is ½ of the maximum diagonal length of the image sensor). According to an embodiment of the invention, the object-side surface of the first lens has a convex shape, the sensor-side surface of the ninth lens has a concave shape, and each of object-side surfaces and sensor-side surfaces of the sixth to ninth lenses may have at least one critical point. According to an embodiment of the invention, the sensor-side surface of the first lens and an object-side surface of the fourth lens have at least one critical point, and the object-side surface and the sensor-side surface of the third lens may have at least one critical point. According to an embodiment of the invention, a relationship between a distance (BFL) on the optical axis from the image sensor to the sensor side of the last lens and ImgH may satisfy the following equation: 0.01<BFL/ImgH<0.5. According to an embodiment of the invention, a relationship between effective diameters of the first lens and the ninth lens and the total numb