KR-20260066361-A - OPTICAL SYSTEM AND CAMERA MODULE

KR20260066361AKR 20260066361 AKR20260066361 AKR 20260066361AKR-20260066361-A

Abstract

An optical system according to an embodiment of the present invention comprises first to fourth lens groups arranged along an optical axis, wherein the first lens group has a positive (+) refractive power, the second lens group has a positive (+) refractive power, and the third lens group has a negative (-) refractive power, and the first lens group and the fourth lens group include prism lenses, and the first lens group, the second lens group and the fourth lens group are fixed groups, and the third lens group is a moving group.

Inventors

문성민
이상훈

Assignees

엘지이노텍 주식회사

Dates

Publication Date: 20260512
Application Date: 20241104

Claims (15)

It includes first to fourth lens groups arranged along the optical axis, and The above first lens group has a positive (+) refractive power, and The above second lens group has a positive (+) refractive power, and The above third lens group has negative (-) refractive power, and The first lens group and the fourth lens group include prism lenses, The first lens group, the second lens group, and the fourth lens group are fixed groups, and The above third lens group is an optical system that is a moving group.
In paragraph 1, The first lens group above is an optical system comprising a single power prism lens having a convex side on the object and a concave side on the sensor.
In paragraph 1, The above first lens group includes a first lens, a second lens which is a prism lens, and a third lens, and The first to third lenses mentioned above are bonded lenses, and The above second lens group includes a fourth lens, a fifth lens, and a sixth lens, and The above third lens group is an optical system including a seventh lens and an eighth lens.
In paragraph 3, The first lens above has a positive (+) refractive power, and The above third lens is an optical system having negative (-) refractive power.
In paragraph 3, The above-mentioned fourth lens has a positive (+) refractive power, and The above-mentioned fifth lens has a positive (+) refractive power, and The above-mentioned sixth lens is an optical system having negative (-) refractive power.
In paragraph 3, The above seventh lens has a negative (-) refractive power, and The above eighth lens is an optical system having positive (+) refractive power.
In paragraph 3, The above-mentioned fourth lens and fifth lens are an optical system having a meniscus shape with a convex side surface.
In paragraph 3, An optical system in which an aperture is positioned between the sixth lens and the seventh lens.
In paragraph 3, An optical system in which the refractive index of the second lens is smaller than the refractive index of the ninth lens.
In paragraph 1, An optical system satisfying the following condition. <Condition> 1 < TD_LG2 / TD_LG3 < 2 (In the above conditional equation, TD_LG2 is the length of the second lens group in the optical axis direction, and TD_LG3 is the length of the third lens group in the optical axis direction.)
It includes first to ninth lenses arranged along the optical axis, and The second lens and the ninth lens are prism lenses, and The first lens above has a positive (+) refractive power, and The above third lens has a negative (-) refractive power, and The above-mentioned fourth lens has a positive (+) refractive power, and The above-mentioned fifth lens has a positive (+) refractive power, and The above-mentioned sixth lens has a negative (-) refractive power, and The above seventh lens has a negative (-) refractive power, and The above eighth lens is an optical system having positive (+) refractive power.
In Paragraph 11, The first to third lenses above are a first group of lenses having positive (+) refractive power, and The above 4th to 6th lenses are a second lens group having positive (+) refractive power, and The above 7th and 8th lenses are an optical system that is a third lens group having negative (-) refractive power.
In Paragraph 11, The first lens group and the second lens group are fixed groups, and The above third lens group is an optical system that is a moving group.
In Paragraph 11, An optical system satisfying the following condition. <Condition> 0.9 < PT1 / PT2 < 1.2 (In the above conditional equation, PT1 is the optical axis thickness of the second lens, and PT2 is the optical axis thickness of the ninth lens.)
In Paragraph 11, An optical system satisfying the following condition. <Condition> 2 < TTL / ImgH < 5 (In the above conditional equation, TTL is the optical axis distance from the vertex of the object side of the first lens to the top plane of the image sensor, and ImgH is the maximum diagonal length of the image sensor.)

Description

Optical System and Camera Module The present invention relates to an optical system for enhanced optical performance and a camera module including the same. Camera modules perform the function of capturing objects and saving them as images or videos, and are installed in various applications. In particular, camera modules are manufactured in ultra-compact sizes and are applied not only to portable devices such as smartphones, tablet PCs, and laptops, but also to drones and vehicles, providing a wide range of functions. For example, the optical system of a camera module may include an imaging lens that forms an image and an image sensor that converts the formed image into an electrical signal. In this case, the camera module can perform an autofocus (AF) function that aligns the focal length of the lens by automatically adjusting the distance between the image sensor and the imaging lens, and can perform a zooming function of zooming up or zooming out by increasing or decreasing the magnification of a distant object through a zoom lens. Additionally, the camera module employs image stabilization (IS) technology to correct or prevent image shaking caused by camera movement resulting from unstable fixed devices or user movements. The most important element for such camera modules to obtain an image is the imaging lens that forms the image. Recently, there has been growing interest in high performance, such as high image quality and high resolution, and research is being conducted on optical systems containing multiple lenses to achieve this. For example, research is being conducted using multiple imaging lenses with positive (+) or negative (-) refractive power to implement a high-performance optical system. An optical system containing multiple lenses may have a set Effective Focal Length (EFL). In this case, when the value of the Effective Focal Length (EFL) is relatively large, the lens adjacent to the object side has a large aperture or the largest aperture among the multiple lenses. Consequently, since the lens closest to the object side has a relatively large size, there is a problem in that it is difficult to miniaturize the optical system. An optical system containing multiple lenses may have a relatively large height. For example, as the number of lenses increases, the distance from the image sensor to the object surface of the lens adjacent to the object may increase. Accordingly, the overall thickness of a device such as a mobile device like a smartphone in which the optical system is placed may increase, and there is a problem that it is difficult to miniaturize. Camera modules for close-range imaging have a shorter TTL compared to conventional camera modules. As another example, camera modules for long-range imaging have a longer TTL compared to conventional camera modules. However, since portable terminals have limited installation space for camera modules, it is difficult to mount camera modules for long-range imaging or camera modules capable of adjusting image magnification (zoom camera modules). Therefore, a new optical system capable of solving the aforementioned problems is required. FIG. 1 is a diagram showing the configuration of an optical system according to the present embodiment operating in a first mode. FIG. 2 is a configuration diagram of an optical system according to the present embodiment operating in a second mode. FIG. 3 is a table showing the aspherical coefficients of lenses in an optical system according to the present embodiment. FIG. 4 is a graph showing data on the aberration characteristics of the optical system according to the present embodiment operating in the first mode. FIG. 5 is a drawing for explaining the D-cut lens of the present invention. FIG. 6 is an example of a portable terminal having an optical system according to the present embodiment. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted. In addition, terms used in this embodiment (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which this embodiment belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology. Furthermore, the terms used in this embodiment are for the purpose of describing the embodiment and are not intended to limit the invention. In this specification, the singular form may include the plural form unless specifically stated otherwise in the text,