Search

CN-121986281-A - Optical system and camera module

CN121986281ACN 121986281 ACN121986281 ACN 121986281ACN-121986281-A

Abstract

Disclosed in an embodiment of the present invention is a camera module including a first lens group having a negative (-) refractive power, second and third lens groups disposed on a sensor side of the first lens group, and a fourth lens group disposed on a sensor side of the third lens group and having a negative (-) refractive power, wherein the second and third lens groups perform a zoom magnification from a wide angle mode to a telephoto mode by moving along an optical axis of lenses among the first to fourth lens groups, a number of lenses in at least one of the second and third lens groups is greater than a number of lenses in the fourth lens group, an optical axis distance of the second lens group is greater than an optical axis distance of the first lens group, and the fourth lens group may include a lens having a maximum effective length among the effective lengths of lenses among the first to fourth lens groups.

Inventors

  • WEN SHENGMIN

Assignees

  • LG伊诺特有限公司

Dates

Publication Date
20260505
Application Date
20240807
Priority Date
20230807

Claims (13)

  1. 1. A camera module, comprising: A first lens group disposed adjacent to the object and having a negative (-) refractive power; a second lens group disposed on a sensor side of the first lens group; a third lens group disposed on the sensor side of the second lens group, and A fourth lens group disposed on a sensor side of the third lens group and having a negative (-) refractive power, Wherein the second lens group and the third lens group are moved along an optical axis of a lens in the first lens group to the fourth lens group to perform a zoom magnification from a wide angle mode to a telephoto mode, Wherein the number of lenses in at least one of the second lens group and the third lens group is greater than the number of lenses in the fourth lens group, Wherein the optical axis distance of the second lens group is larger than that of the first lens group, and Wherein the fourth lens group includes a lens having a largest effective length among the effective lengths of lenses in the first to fourth lens groups.
  2. 2. The camera module of claim 1, Wherein a maximum moving distance of the second lens group or the third lens group is defined as Max_ mMd13 according to the zoom magnification, and Wherein the following mathematical expression 1 mm<Max_mMd13<7 mm is satisfied.
  3. 3. The camera module of claim 1, Wherein a minimum optical axis distance between the first lens group and the second lens group in the tele mode is Md3_DG12, and Wherein the following mathematical expression is satisfied that Md3_DG12 is more than or equal to 0.5mm and less than or equal to 1.5 mm.
  4. 4. A camera module according to any one of claims 1 to 3, wherein a lens closest to an object in the first lens group has a positive refractive power and a meniscus shape protruding toward the object.
  5. 5. The camera module of claim 4, wherein a lens of the seventh lens group closest to the image sensor has a positive refractive power and a biconvex shape.
  6. 6. The camera module according to claim 5, wherein a lens closest to the image sensor among lenses included in the first to fourth lens groups has a maximum effective length.
  7. 7. The camera module of any one of claims 1 to 4, Wherein the seventh lens is made of glass.
  8. 8. The camera module of any of claims 1 to 4, wherein the first lens has a spherical shape and is made of glass.
  9. 9. The camera module of any one of claims 1 to 4, Wherein the number of lenses in the first lens group is equal to the number of lenses in the second and third lens groups, and Wherein each of the first to third lens groups includes lenses having refractive powers of opposite signs.
  10. 10. The camera module of claim 5, further comprising: A reflecting member disposed at an object side of the first lens group, Wherein the lens closest to the image sensor has a shape in which the effective lengths in a first direction and a second direction perpendicular to the optical axis are different.
  11. 11. A camera module, comprising: A first lens group including a first lens and a second lens arranged in order from an object side toward the image sensor, the first lens group having a negative refractive power; a second lens group disposed on a sensor side of the first lens group; a third lens group disposed on the sensor side of the second lens group, and A fourth lens group having a last lens disposed between the third lens group and the image sensor and having a positive refractive power, Wherein the second lens group and the third lens group are moved along an optical axis of a lens in the first lens group to the fourth lens group to perform a zoom magnification from a wide angle mode to a telephoto mode, Wherein an object-side surface of the first lens has a convex shape on the optical axis, Wherein an absolute value of a radius of curvature of a sensor-side surface of the first lens is larger than a radius of curvature of an object-side surface of the first lens, Wherein the positions of the first lens group and the fourth lens group are fixed on the optical axis, Wherein the number of lenses in the second lens group and the third lens group is smaller than the number of lenses in the fourth lens group, Wherein the optical axis distance of the second lens group is the largest among the optical axis distances of the first lens group to the fourth lens group, Wherein the optical axis distance of the first to fourth lens groups is a distance in the optical axis direction from an object side lens to a sensor side lens provided in each lens group, and Wherein the effective length of the first lens is smaller than the effective length of the last lens and larger than the effective lengths of lenses in the second lens group and the third lens group.
  12. 12. The camera module of claim 11, Wherein the first lens has a refractive index Nd1 and an Abbe number Vd1, Wherein the last lens has a refractive index Ndn and an Abbe number Vdn, an Wherein the following mathematical expression is satisfied: nd1 XVd 1<50, and Ndn × Vdn<50。
  13. 13. The camera module of claim 11, comprising: A reflecting member disposed at an object side of the first lens, Wherein at least one of the first lens and the last lens has a shape in which effective lengths in a first direction and a second direction perpendicular to the optical axis are different.

Description

Optical system and camera module Technical Field Embodiments of the present invention relate to an optical system for improving optical performance and a camera module including the same. Background 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 not only to portable devices such as smart phones, tablet PCs, and laptops, but also to unmanned aerial vehicles and vehicles to provide various functions. For example, an optical system of a 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 Auto Focus (AF) function of aligning a focal length of the lens by automatically adjusting a distance between the image sensor and the imaging lens, and may perform a zoom function of zooming in or out by increasing or decreasing a magnification of a remote object through the zoom lens. In addition, the camera module employs an Image Stabilization (IS) technique to correct or prevent image instability due to an unstable fixture or camera movement caused by movement of a user. The most important element of the camera module for obtaining an image is an imaging lens forming the image. Recently, interest in high efficiency such as high image quality and high resolution is increasing, and research into an optical system including a plurality of lenses is being conducted in order to achieve this. For example, studies are being conducted to realize a high-efficiency optical system using a plurality of imaging lenses having positive (+) and/or negative (-) refractive power. However, there is a problem in that when a plurality of lenses are included, it is difficult to obtain excellent optical and aberration characteristics. In addition, due to the thickness, distance and size of the plurality of lenses, the total length and height may be increased, thereby increasing the total size of the module including the lenses. While the size of image sensors is increasing to achieve high resolution and high quality images, the increase in size of image sensors also increases the Total Track Length (TTL) of the optical system. This causes a problem that the thickness of the camera and the mobile terminal including the optical system also increases. When the optical system includes a plurality of lenses, functions such as zooming and auto-focusing (AF) may be performed by controlling the position of at least one lens or a lens group including at least one lens. However, when a lens or a lens group performs these functions, the movement amount of the lens or the lens group may exponentially increase. Therefore, the optical system may require high energy to perform movement of the lens or the lens group, and a large volume may be required in consideration of the movement amount. Further, there is a problem that aberration characteristics deteriorate with movement of the lens or the lens group, which causes deterioration of optical performance at a specific magnification. Therefore, a new optical system capable of solving the above-described problems is demanded. Disclosure of Invention Technical purpose Embodiments of the present invention provide an optical system having improved optical characteristics. Embodiments provide an optical system and a camera module capable of capturing images at various magnifications. The embodiment provides an optical system and a camera module having improved aberration characteristics at various magnifications. Embodiments provide an optical system and a camera module that can be implemented in a small and compact manner. Technical proposal A camera module according to an embodiment of the present invention includes a first lens group adjacent to an object and having a negative refractive power, a second lens group disposed on a sensor side of the first lens group, a third lens group disposed on a sensor side of the second lens group, and a fourth lens group disposed on a sensor side of the third lens group and having a negative refractive power, wherein the second and third lens groups move along an optical axis of lenses among the first to fourth lens groups to perform a zoom magnification from a wide angle mode to a telephoto mode, a number of lenses among at least one of the second and third lens groups is greater than a number of lenses among the fourth lens group, an optical axis distance of the second lens group is greater than an optical axis distance of the first lens group, and the fourth lens group may include a lens having a maximum effective length among the effective lengths of lenses among the first to fourth lens groups. According to an embodiment of the present invention, the maximum moving distance of the second or third lens group according to the zoom magnification is max_ mMd13, and the following mathematical