Optical imaging system

Abstract

An optical imaging system includes: a first lens having negative refractive power; a second lens; a third lens having a convex image-side surface; a fourth lens; a fifth lens having negative refractive power; a sixth lens having positive refractive power; and a seventh lens having a convex object-side surface. The first to seventh lenses are arranged sequentially from the object side and satisfy TTL / IMH < 1.2, where TTL is the distance along the optical axis from the object-side surface of the first lens to the image plane, and IMH is the height of the image plane.

Description

Optical Imaging System [Cross - Reference to Related Applications] This application claims the benefit of priority of Korean Patent Application No. 10 - 2023 - 0086727, filed on July 4, 2023, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. This disclosure relates to an optical imaging system. A portable terminal may include a wide - angle camera with a short focal length and a telephoto camera with a long focal length to provide images with various magnifications. Large image sensors may be developed for high - pixel counting, and an optical system with a low Fno value may be desired to obtain bright images even when shooting under low - light conditions. The above information is provided only as background information to help understand this disclosure. No determination has been made, nor is any assertion made, as to whether any of the above constitutes prior art to this disclosure. The present invention content is provided to introduce a series of concepts further described in the following embodiments in a simplified form. The present invention content is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to assist in determining the scope of the claimed subject matter. In one general aspect, an optical imaging system includes: a first lens having a negative refractive power; a second lens; a third lens having a convex image - side surface; a fourth lens; a fifth lens having a negative refractive power; a sixth lens having a positive refractive power; and a seventh lens having a convex object - side surface. The first lens to the seventh lens are arranged in order from the object side and satisfy TTL / IMH < 1.2, where TTL is the distance on the optical axis from the object - side surface of the first lens to the image plane, and IMH is the height of the image plane. The second lens may have a positive refractive power, and the image - side surface of the second surface may be concave. The object - side surface of the sixth lens may be concave. It may satisfy 50 < FOV / f, where FOV is the field of view of the optical imaging system and f is the focal length of the optical imaging system. It may satisfy f / EPD < 1.8, where f is the focal length of the optical imaging system and EPD is the diameter of the entrance pupil. It may satisfy L6R1 / CT6 < - 3, where L6R1 is the radius of curvature of the object - side surface of the sixth lens and CT6 is the central thickness of the sixth lens. It may satisfy 15 < v1 - v2 < 40 and 0 < v1 - v5 < 45, where v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, and v5 is the Abbe number of the fifth lens. It can satisfy 1.6 < ET1 / CT1, where ET1 is the edge thickness of the first lens and CT1 is the center thickness of the first lens. The object-side surface of the first lens can be concave, and the fourth lens can have a positive refractive power. The image-side surface of the fifth lens can be concave, and the seventh lens can have a negative refractive power. In another general aspect, an optical imaging system includes: a first lens, both the object-side surface and the image-side surface of the first lens are concave; a second lens; a third lens having a positive refractive power; a fourth lens having a positive refractive power; a fifth lens; a sixth lens having a concave object-side surface; and a seventh lens having a convex object-side surface. The first lens to the seventh lens can be arranged in sequence from the object side. Any one or any combination of any two or more surfaces of the first lens and the seventh lens can include one or more inflection points, and it can satisfy f / EPD < 1.8, where f is the focal length of the optical imaging system and EPD is the diameter of the entrance pupil. It can satisfy SD6 / SD14 < 0.5, where SD6 is the effective diameter of the image-side surface of the third lens and SD14 is the effective diameter of the image-side surface of the seventh lens. The first lens can have a negative refractive power, and it can satisfy -4 < f1 / f < 0, where f1 is the focal length of the first lens and f is the focal length of the optical imaging system. The image-side surface of the fifth lens can be convex, and the seventh lens can have a positive refractive power. The image-side surface of the fifth lens can be concave, and the seventh lens can have a negative refractive power. It can satisfy TTL / IMH < 1.2, where TTL is the distance on the optical axis from the object-side surface of the first lens to the image plane, and IMH is the height of the image plane. Other features and aspects will become apparent by reading the following detailed description, drawings, and claims. Hereinafter, examples of the present disclosure will be described in detail with reference to the accompanying drawings, but it should be noted that the examples are not limited thereto. The following detailed description is provided to assist the reader in fully understanding the methods, apparatuses, and / or systems described herein. However, after understanding the present disclosure, various changes, modifications, and equivalent forms of the methods, apparatuses, and / or systems described herein will become apparent. For example, the order of operations described herein is only an example and is not limited to the order described herein, but can be changed, which will become apparent after understanding the present disclosure, except for operations that must be performed in a specific order. In addition, for greater clarity and conciseness, descriptions of features known in the art may be omitted. The features described herein can be implemented in different forms and should not be construed as limited to the examples set forth herein. Rather, the examples set forth herein are for illustrative purposes only of some of the many possible ways of implementing the methods, apparatuses, and / or systems described herein, which will become apparent after understanding this disclosure. Throughout this specification, when an element such as a layer, region, or substrate is described as being "on," "connected to," or "coupled to" another element, the element can be directly "on," directly "connected to," or directly "coupled to" the other element, or there can be one or more other elements intervening therebetween. In contrast, when an element is described as being "directly on," "directly connected to," or "directly coupled to" another element, there can be no other elements intervening therebetween. As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more of them; likewise, "at least one of..." includes any one of the associated listed items and any combination of any two or more of them. Although terms such as "first," "second," and "third" may be used herein to describe various components, elements, regions, layers, or sections, such components, elements, regions, layers, or sections are not limited by these terms. Rather, these terms are only used to distinguish between individual components, elements, regions, layers, or sections. Thus, without departing from the teachings of the examples, the first component, first element, first region, first layer, or first section mentioned in the examples herein can also be referred to as the second component, second element, second region, second layer, or second section. For ease of explanation, spatial relative terms such as "above," "upper," "below," "lower," and similar terms may be used herein to describe the relationship of one element shown in the figures to another element. Such spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as being "above" or "upper" relative to another element will then be "below" or "lower" relative to the other element. Thus, the term "above" encompasses both the above and below orientations depending on the spatial orientation of the device. The device can also be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative terms used herein should be interpreted accordingly. The terms used in this document are only for describing various examples and are not used to limit this disclosure. Unless the context clearly indicates otherwise, the articles "a," "an," and "the" are intended to include the plural forms as well. The terms "comprises," "includes," and "has" indicate the presence of the stated features, numbers, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, numbers, operations, components, elements, and / or combinations thereof. Due to manufacturing techniques and / or tolerances, the shapes shown in the figures may vary. Therefore, the examples described herein are not limited to the specific shapes shown in the figures, but include shape variations that occur during manufacturing. In this document, it should be noted that the use of the term "may" with respect to an example (e.g., what may be included or implemented with respect to an example) means that there is at least one example in which such a feature is included or implemented, but not all examples are limited thereto. As will be apparent after understanding this disclosure, the features of the examples described herein can be combined in various ways. In addition, although the examples described herein have various configurations, other configurations are also possible as will be apparent after understanding this disclosure. In this specification, in the description of the lens shape, a configuration in which one surface is convex means that the paraxial region of the surface is convex, and a configuration in which one surface is concave means that the paraxial region of the surface is concave. Therefore, even when it is stated that one surface of a lens is convex, the edge of the lens can be concave. Similarly, even when it is stated that one surface of a lens is concave, the edge of the lens can be convex. According to this disclosure, an optical imaging system may include seven lenses arranged along the optical axis. For example, the optical imaging system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens that can be sequentially arranged along the optical axis from the object side. According to this disclosure, in the optical imaging system, the first lens refers to the lens closest to the object (or subject), and the seventh lens refers to the lens closest to the image sensor. According to this disclosure, an optical imaging system may include an image sensor for converting the light passing through the lens into an electrical signal and an infrared (IR) cut-off filter for blocking the light in the infrared region of the light passing through the lens. The image sensor may include an image plane on which an object image is formed, and the IR cut-off filter may be disposed between the lens closest to the image sensor and the image sensor. According to this disclosure, an optical imaging system may include a diaphragm for adjusting the amount of light. For example, the optical imaging system may include a diaphragm between the second lens and the third lens. According to the present disclosure, the optical imaging system may include a lens formed of a plastic material. For example, at least one of the first lens to the seventh lens may be a lens formed of a plastic material, and preferably, all of the first lens to the seventh lens may be lenses formed of a plastic material. In addition, at least some of the first lens to the seventh lens may be formed of different plastic materials having different refractive indices and / or Abbe numbers. According to the present disclosure, the optical imaging system may include an aspherical lens. For example, at least one of the object-side surface and the image-side surface of at least one of the first lens to the seventh lens may have an aspherical surface. The aspherical surfaces of the first lens to the seventh lens may be represented by Equation 1 below. [Equation 1] In Equation 1, c is the reciprocal of the radius of curvature of the lens, k is the conic constant, Y is the distance from an arbitrary point on the aspherical surface to the optical axis, A to H, J, and L to P are the aspherical surface constants from the 4th order to the 30th order in sequence, and Z (or sag) is the distance from an arbitrary point on the aspherical surface to the vertex of the corresponding aspherical surface in the optical axis direction. In addition, according to the present disclosure, the optical imaging system may satisfy at least one of the following conditional expressions. [Conditional Expression 1] -4 < f1 / f < 0 [Conditional Expression 2] f / EPD < 1.8 [Conditional Expression 3] 15 < v1 - v2 < 40 [Conditional Expression 4] 25 < v1 - v5 < 45 [Conditional Expression 5] 0 < v1 - v7 < 40 [Conditional Expression 6] TTL / IMH < 1.2 [Conditional Expression 7] 50 < FOV / f (unit: millimeter -1 ) [Conditional Expression 8] L6R1 / CT6 < -3 [Conditional Expression 9] 1.6 < ET1 / CT1 [Conditional Expression 10] 2.5 < SD1 / SD5 < 4 [Conditional Expression 11] SD6 / SD14 < 0.5 In [Conditional Expression 1], f1 is the focal length of the first lens, and f is the focal length of the optical imaging system. Only when the range according to [Conditional Expression 1] is satisfied can a wide field of view (suitable for the field of view of an ultra-wide-angle lens) be ensured. In [Conditional Expression 2], f is the focal length of the optical imaging system, and EPD is the diameter of the entrance pupil. [Conditional Expression 2] shows the condition (f-number) defining the brightness of the optical imaging system, and only when the range according to [Conditional Expression 2] is satisfied can a desired bright optical system be implemented. In [Conditional Expression 3] to [Conditional Expression 5], v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, v5 is the Abbe number of the fifth lens, and v7 is the Abbe number of the seventh lens. Chromatic aberration can be minimized only when the ranges according to [Conditional Expression 3] to [Conditional Expression 5] are satisfied. In [Conditional Expression 6], TTL is the distance on the optical axis from the object-side surface of the first lens to the image plane, and IMH is the height of the image plane (half of the diagonal length). Miniaturization can be achieved only when the range according to [Conditional Expression 6] is satisfied. In [Conditional Expression 7], FOV is the field of view of the optical imaging system, and f is the focal length of the optical imaging system. The purpose of a wide-angle lens can be achieved only when the range according to [Conditional Expression 7] is satisfied. In [Conditional Expression 8], L6R1 is the radius of curvature of the object-side surface of the sixth lens, and CT6 is the central thickness of the sixth lens. When L6R1 / CT6 exceeds the range according to [Conditional Expression 8], it becomes difficult to correct the light blur phenomenon. In [Conditional Expression 9], ET1 is the edge thickness of the first lens, and CT1 is the central thickness of the first lens. When ET1 / CT1 exceeds the range according to [Conditional Expression 9], it becomes difficult to ensure the ambient light ratio and correct aberrations. In [Conditional Expression 10], SD1 is the effective diameter of the object-side surface of the first lens, and SD5 is the effective diameter of the object-side surface of the third lens. When SD1 / SD5 exceeds the range according to [Conditional Expression 10], it becomes difficult to implement a wide field of view. In [Conditional Expression 11], SD6 is the effective diameter of the image side of the third lens, and SD14 is the effective diameter of the image side of the seventh lens. When SD6 / SD14 exceeds the range according to [Conditional Expression 11], it becomes difficult to achieve high resolution. Hereinafter, various embodiments of the optical imaging system will be described according to the present disclosure. - First Embodiment - FIG. 1 is a configuration diagram of an optical imaging system according to a first embodiment of the present disclosure, and FIG. 2 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 1. According to a first embodiment of the present disclosure, the optical imaging system 100 may include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens 170. The first lens 110 may have a negative refractive power, and both the object-side surface and the image-side surface of the first lens 110 may be concave. Additionally, the object-side surface of the first lens 110 may include at least one inflection point. That is, the object-side surface of the first lens 110 may be concave in the paraxial portion but convex in the peripheral portion. The second lens 120 may have a positive refractive power, the object-side surface of the second lens 120 may be convex, and the image-side surface of the second lens 120 may be concave. The third lens 130 may have a positive refractive power, and both the object-side surface and the image-side surface of the third lens 130 may be convex. The fourth lens 140 may have a positive refractive power, and both the object-side surface and the image-side surface of the fourth lens 140 may be convex. The fifth lens 150 may have a negative refractive power, the object-side surface of the fifth lens 150 may be concave, and the image-side surface of the fifth lens 150 may be convex. The sixth lens 160 may have a positive refractive power, the object-side surface of the sixth lens 160 may be concave, and the image-side surface of the sixth lens 160 may be convex. The seventh lens 170 may have a positive refractive power, the object-side surface of the seventh lens 170 may be convex, and the image-side surface of the seventh lens 170 may be concave. Additionally, each of the object-side surface and the image-side surface of the seventh lens 170 may include at least one inflection point. That is, the object-side surface of the seventh lens 170 may be convex in the paraxial portion but concave in the peripheral portion, and the image-side surface of the seventh lens 170 may be concave in the paraxial portion but convex in the peripheral portion. The optical imaging system 100 according to the first embodiment of the present disclosure may include an infrared cut-off filter 180 and an image sensor 190 after the seventh lens 170, and may further include a diaphragm between the second lens 120 and the third lens 130. Table 1 shows the characteristics of the optical imaging system 100 according to the first embodiment of the present disclosure. According to the first embodiment of the present disclosure, the focal length of the optical imaging system 100 is 2.0 mm, the field of view is 125.0 degrees, the height of the image plane is 7.0 mm, and the F-number is 1.7. [Table 1] Table 2 shows the aspherical values of the optical imaging system 100 according to the first embodiment of the present disclosure. [Table 2] -Second Embodiment- FIG. 3 is a configuration diagram of an optical imaging system according to the second embodiment of the present disclosure, and FIG. 4 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 3. According to the second embodiment of the present disclosure, the optical imaging system 200 may include a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, and a seventh lens 270. The first lens 210 may have a negative refractive power, and both the object-side surface and the image-side surface of the first lens 210 may be concave. Additionally, the object-side surface of the first lens 210 may include at least one inflection point. That is, the object-side surface of the first lens 210 may be concave in the paraxial portion but convex in the marginal portion. The second lens 220 may have a positive refractive power, the object-side surface of the second lens 220 may be convex, and the image-side surface of the second lens 220 may be concave. The third lens 230 may have a positive refractive power, and both the object-side surface and the image-side surface of the third lens 230 may be convex. The fourth lens 240 may have a positive refractive power, and both the object-side surface and the image-side surface of the fourth lens 240 may be convex. The fifth lens 250 may have a negative refractive power, and both the object-side surface and the image-side surface of the fifth lens 250 may be concave. Additionally, the image-side surface of the fifth lens 250 may include at least one inflection point. That is, the image-side surface of the fifth lens 250 may be concave in the paraxial portion but convex in the marginal portion. The sixth lens 260 may have a positive refractive power, the object-side surface of the sixth lens 260 may be concave, and the image-side surface of the sixth lens 260 may be convex. The seventh lens 270 may have a negative refractive power, the object-side surface of the seventh lens 270 may be convex, and the image-side surface of the seventh lens 270 may be concave. Additionally, each of the object-side surface and the image-side surface of the seventh lens 270 may include at least one inflection point. That is, the object-side surface of the seventh lens 270 may be convex in the paraxial portion but concave in the marginal portion, and the image-side surface of the seventh lens 270 may be concave in the paraxial portion but convex in the marginal portion. According to the second embodiment of the present disclosure, the optical imaging system 200 may include an infrared cut-off filter 280 and an image sensor 290 after the seventh lens 270, and may further include a diaphragm between the second lens 220 and the third lens 230. Table 3 shows the characteristics of the optical imaging system 200 according to the second embodiment of the present disclosure. According to the second embodiment of the present disclosure, the focal length of the optical imaging system 200 is 2.0 mm, the field of view is 125.0 degrees, the height of the image plane is 7.0 mm, and the F-number is 1.7. [Table 3] Table 4 shows the aspherical values of the optical imaging system 200 according to the second embodiment of the present disclosure. [Table 4] - Third Embodiment - FIG. 5 is a configuration diagram of an optical imaging system according to the third embodiment of the present disclosure, and FIG. 6 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 5. The optical imaging system 300 according to the third embodiment of the present disclosure may include a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, and a seventh lens 370. The first lens 310 may have a negative refractive power, and both the object-side surface and the image-side surface of the first lens 310 may be concave. Additionally, the object-side surface of the first lens 310 may include at least one inflection point. That is, the object-side surface of the first lens 310 may be concave in the paraxial portion but convex in the marginal portion. The second lens 320 may have a positive refractive power, the object-side surface of the second lens 320 may be convex, and the image-side surface of the second lens 320 may be concave. The third lens 330 may have a positive refractive power, and both the object-side surface and the image-side surface of the third lens 330 may be convex. The fourth lens 340 may have a positive refractive power, and both the object-side surface and the image-side surface of the fourth lens 340 may be convex. The fifth lens 350 may have a negative refractive power, and both the object-side surface and the image-side surface of the fifth lens 350 may be concave. Additionally, the image-side surface of the fifth lens 350 may include at least one inflection point. That is, the image-side surface of the fifth lens 350 may be concave in the paraxial portion but convex in the marginal portion. The sixth lens 360 may have a positive refractive power, the object-side surface of the sixth lens 360 may be concave, and the image-side surface of the sixth lens 360 may be convex. The seventh lens 370 may have a negative refractive power, the object-side surface of the seventh lens 370 may be convex, and the image-side surface of the seventh lens 370 may be concave. Additionally, each of the object-side surface and the image-side surface of the seventh lens 370 may include at least one inflection point. That is, the object-side surface of the seventh lens 370 may be convex in the paraxial portion but concave in the marginal portion, and the image-side surface of the seventh lens 370 may be concave in the paraxial portion but convex in the marginal portion. The optical imaging system 300 according to the third embodiment of the present disclosure may include an infrared cut-off filter 380 and an image sensor 390 after the seventh lens 370, and may further include a diaphragm between the second lens 320 and the third lens 330. Table 5 shows the characteristics of the optical imaging system 300 according to the third embodiment of the present disclosure. According to the third embodiment of the present disclosure, the focal length of the optical imaging system 300 is 2.0 mm, the field of view is 125.2 degrees, the height of the image plane is 7.0 mm, and the F number is 1.7. [Table 5] Table 6 is a table showing the aspherical values of the optical imaging system 300 according to the third embodiment of the present disclosure. [Table 6] - Fourth Embodiment - FIG. 7 is a configuration diagram of an optical imaging system according to the fourth embodiment of the present disclosure, and FIG. 8 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 7. According to the fourth embodiment of the present disclosure, the optical imaging system 400 may include a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, and a seventh lens 470. The first lens 410 may have a negative refractive power, and both the object-side surface and the image-side surface of the first lens 410 may be concave. In addition, the object-side surface of the first lens 410 may include at least one inflection point. That is, the object-side surface of the first lens 410 may be concave in the paraxial portion, but convex in the edge portion. The second lens 420 may have a positive refractive power, the object-side surface of the second lens 420 may be convex, and the image-side surface of the second lens 420 may be concave. The third lens 430 may have a positive refractive power, and both the object-side surface and the image-side surface of the third lens 430 may be convex. The fourth lens 440 may have a positive refractive power, and both the object-side surface and the image-side surface of the fourth lens 440 may be convex. The fifth lens 450 may have a negative refractive power, and both the object-side surface and the image-side surface of the fifth lens 450 may be concave. In addition, the image-side surface of the fifth lens 450 may include at least one inflection point. That is, the image-side surface of the fifth lens 450 may be concave in the paraxial portion, but convex in the edge portion. The sixth lens 460 may have a positive refractive power, the object-side surface of the sixth lens 460 may be concave, and the image-side surface of the sixth lens 460 may be convex. The seventh lens 470 may have a negative refractive power, the object-side surface of the seventh lens 470 may be convex, and the image-side surface of the seventh lens 470 may be concave. In addition, each of the object-side surface and the image-side surface of the seventh lens 470 may include at least one inflection point. That is, the object-side surface of the seventh lens 470 may be convex in the paraxial portion, but concave in the edge portion, and the image-side surface of the seventh lens 470 may be concave in the paraxial portion, but convex in the edge portion. According to the fourth embodiment of the present disclosure, the optical imaging system 400 may include an infrared cut-off filter 480 and an image sensor 490 after the seventh lens 470, and may further include a diaphragm between the second lens 420 and the third lens 430. Table 7 shows the characteristics of the optical imaging system 400 according to the fourth embodiment of the present disclosure. According to the fourth embodiment of the present disclosure, the focal length of the optical imaging system 400 is 2.0 mm, the field of view is 125.0 degrees, the height of the image plane is 7.0 mm, and the F number is 1.7. [Table 7] Table 8 is a table showing the aspherical values of the optical imaging system 400 according to the fourth embodiment of the present disclosure. [Table 8] - Fifth Embodiment - FIG. 9 is a configuration diagram of an optical imaging system according to the fifth embodiment of the present disclosure, and FIG. 10 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 9. According to the fifth embodiment of the present disclosure, the optical imaging system 500 may include a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560, and a seventh lens 570. The first lens 510 may have a negative refractive power, and both the object-side surface and the image-side surface of the first lens 510 may be concave. Additionally, the object-side surface of the first lens 510 may include at least one inflection point. That is, the object-side surface of the first lens 510 may be concave in the paraxial portion but convex in the marginal portion. The second lens 520 may have a positive refractive power, the object-side surface of the second lens 520 may be convex, and the image-side surface of the second lens 520 may be concave. The third lens 530 may have a positive refractive power, and both the object-side surface and the image-side surface of the third lens 530 may be convex. The fourth lens 540 may have a positive refractive power, and both the object-side surface and the image-side surface of the fourth lens 540 may be convex. The fifth lens 550 may have a negative refractive power, and both the object-side surface and the image-side surface of the fifth lens 550 may be concave. Additionally, the image-side surface of the fifth lens 550 may include at least one inflection point. That is, the image-side surface of the fifth lens 550 may be concave in the paraxial portion but convex in the marginal portion. The sixth lens 560 may have a positive refractive power, the object-side surface of the sixth lens 560 may be concave, and the image-side surface of the sixth lens 560 may be convex. The seventh lens 570 may have a negative refractive power, the object-side surface of the seventh lens 570 may be convex, and the image-side surface of the seventh lens 570 may be concave. Additionally, each of the object-side surface and the image-side surface of the seventh lens 570 may include at least one inflection point. That is, the object-side surface of the seventh lens 570 may be convex in the paraxial portion but concave in the marginal portion, and the image-side surface of the seventh lens 570 may be concave in the paraxial portion but convex in the marginal portion. According to the fifth embodiment of the present disclosure, the optical imaging system 500 may include an infrared cut-off filter 580 and an image sensor 590 after the seventh lens 570, and may further include a diaphragm between the second lens 520 and the third lens 530. Table 9 shows the characteristics of the optical imaging system 500 according to the fifth embodiment of the present disclosure. According to the fifth embodiment of the present disclosure, the focal length of the optical imaging system 500 is 2.0 mm, the field of view is 125.2 degrees, the height of the image plane is 7.0 mm, and the F number is 1.7. [Table 9] Table 10 is a table showing the aspherical values of the optical imaging system 500 according to the fifth embodiment of the present disclosure. [Table 10] - Sixth Embodiment - FIG. 11 is a configuration diagram of an optical imaging system according to the sixth embodiment of the present disclosure, and FIG. 12 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 11. According to the sixth embodiment of the present disclosure, the optical imaging system 600 may include a first lens 610, a second lens 620, a third lens 630, a fourth lens 640, a fifth lens 650, a sixth lens 660, and a seventh lens 670. The first lens 610 may have a negative refractive power, and both the object-side surface and the image-side surface of the first lens 610 may be concave. Additionally, the object-side surface of the first lens 610 may include at least one inflection point. That is, the object-side surface of the first lens 610 may be concave in the paraxial portion but convex in the peripheral portion. The second lens 620 may have a positive refractive power, the object-side surface of the second lens 620 may be convex, and the image-side surface of the second lens 620 may be concave. The third lens 630 may have a positive refractive power, and both the object-side surface and the image-side surface of the third lens 630 may be convex. The fourth lens 640 may have a positive refractive power, the object-side surface of the fourth lens 640 may be concave, and the image-side surface of the fourth lens 640 may be convex. The fifth lens 650 may have a negative refractive power, and both the object-side surface and the image-side surface of the fifth lens 650 may be concave. Additionally, the image-side surface of the fifth lens 550 may include at least one inflection point. That is, the image-side surface of the fifth lens 650 may be concave in the paraxial portion but convex in the peripheral portion. The sixth lens 660 may have a positive refractive power, the object-side surface of the sixth lens 660 may be concave, and the image-side surface of the sixth lens 660 may be convex. The seventh lens 670 may have a negative refractive power, the object-side surface of the seventh lens 670 may be convex, and the image-side surface of the seventh lens 670 may be concave. Additionally, each of the object-side surface and the image-side surface of the seventh lens 670 may include at least one inflection point. That is, the object-side surface of the seventh lens 670 may be convex in the paraxial portion but concave in the peripheral portion, and the image-side surface of the seventh lens 670 may be concave in the paraxial portion but convex in the peripheral portion. According to the sixth embodiment of the present disclosure, the optical imaging system 600 may include an infrared cut-off filter 680 and an image sensor 690 after the seventh lens 670, and may further include a diaphragm between the second lens 620 and the third lens 630. Table 11 shows the characteristics of the optical imaging system 600 according to the sixth embodiment of the present disclosure. According to the sixth embodiment of the present disclosure, the focal length of the optical imaging system 600 is 1.9 mm, the field of view is 124.5 degrees, the height of the image plane is 7.0 mm, and the F-number is 1.7. [Table 11] Table 12 shows the aspherical values of the optical imaging system 600 according to the sixth embodiment of the present disclosure. [Table 12] - Seventh Embodiment - FIG. 13 is a configuration diagram of an optical imaging system according to the seventh embodiment of the present disclosure, and FIG. 14 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 13. According to the seventh embodiment of the present disclosure, the optical imaging system 700 may include a first lens 710, a second lens 720, a third lens 730, a fourth lens 740, a fifth lens 750, a sixth lens 760, and a seventh lens 770. The first lens 710 may have a negative refractive power, and both the object-side surface and the image-side surface of the first lens 710 may be concave. Additionally, the object-side surface of the first lens 710 may include at least one inflection point. That is, the object-side surface of the first lens 710 may be concave in the paraxial region but convex in the edge portion. The second lens 720 may have a positive refractive power, the object-side surface of the second lens 720 may be convex, and the image-side surface of the second lens 720 may be concave. The third lens 730 may have a positive refractive power, and both the object-side surface and the image-side surface of the third lens 730 may be convex. The fourth lens 740 may have a positive refractive power, and both the object-side surface and the image-side surface of the fourth lens 740 may be convex. The fifth lens 750 may have a negative refractive power, and both the object-side surface and the image-side surface of the fifth lens 750 may be concave. Additionally, the image-side surface of the fifth lens 750 may include at least one inflection point. That is, the image-side surface of the fifth lens 750 may be concave in the paraxial region but convex in the edge portion. The sixth lens 760 may have a positive refractive power, the object-side surface of the sixth lens 760 may be concave, and the image-side surface of the sixth lens 760 may be convex. The seventh lens 770 may have a negative refractive power, the object-side surface of the seventh lens 770 may be convex, and the image-side surface of the seventh lens 770 may be concave. Additionally, each of the object-side surface and the image-side surface of the seventh lens 770 may include at least one inflection point. That is, the object-side surface of the seventh lens 770 may be convex in the paraxial portion but concave in the edge portion, and the image-side surface of the seventh lens 770 may be concave in the paraxial portion but convex in the edge portion. According to the seventh embodiment of the present disclosure, the optical imaging system 700 may include an infrared cut-off filter 780 and an image sensor 790 after the seventh lens 770, and may further include a diaphragm between the second lens 720 and the third lens 730. Table 13 shows the characteristics of the optical imaging system 700 according to the seventh embodiment of the present disclosure. According to the seventh embodiment of the present disclosure, the focal length of the optical imaging system 700 is 2.0 mm, the field of view is 124.1 degrees, the height of the image plane is 7.0 mm, and the F-number is 1.7. [Table 13] Table 14 shows the aspherical values of the optical imaging system 700 according to the seventh embodiment of the present disclosure. [Table 14] - Eighth Embodiment - FIG. 15 is a configuration diagram of an optical imaging system according to the eighth embodiment of the present disclosure. FIG. 16 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 15. According to the eighth embodiment of the present disclosure, the optical imaging system 800 may include a first lens 810, a second lens 820, a third lens 830, a fourth lens 840, a fifth lens 850, a sixth lens 860, and a seventh lens 870. The first lens 810 may have a negative refractive power, and both the object-side surface and the image-side surface of the first lens 810 may be concave. Additionally, the object-side surface of the first lens 810 may include at least one inflection point. That is, the object-side surface of the first lens 810 may be concave in the paraxial portion but convex in the marginal portion. The second lens 820 may have a positive refractive power, the object-side surface of the second lens 820 may be convex, and the image-side surface of the second lens 820 may be concave. The third lens 830 may have a positive refractive power, and both the object-side surface and the image-side surface of the third lens 830 may be convex. The fourth lens 840 may have a positive refractive power, and both the object-side surface and the image-side surface of the fourth lens 840 may be convex. The fifth lens 850 may have a negative refractive power, and both the object-side surface and the image-side surface of the fifth lens 850 may be concave. Additionally, the image-side surface of the fifth lens 850 may include at least one inflection point. That is, the image-side surface of the fifth lens 850 may be concave in the paraxial portion but convex in the marginal portion. The sixth lens 860 may have a positive refractive power, the object-side surface of the sixth lens 860 may be concave, and the image-side surface of the sixth lens 860 may be convex. The seventh lens 870 may have a negative refractive power, the object-side surface of the seventh lens 870 may be convex, and the image-side surface of the seventh lens 870 may be concave. Additionally, each of the object-side surface and the image-side surface of the seventh lens 870 may include at least one inflection point. That is, the object-side surface of the seventh lens 870 may be convex in the paraxial portion but concave in the marginal portion, and the image-side surface of the seventh lens 870 may be concave in the paraxial portion but convex in the marginal portion. According to the eighth embodiment of the present disclosure, the optical imaging system 800 may include an infrared cut-off filter 880 and an image sensor 890 after the seventh lens 870, and may further include a diaphragm between the second lens 820 and the third lens 830. Table 15 shows the characteristics of the optical imaging system 800 according to the eighth embodiment of the present disclosure. According to the eighth embodiment of the present disclosure, the focal length of the optical imaging system 800 is 2.0 mm, the field of view is 124.3 degrees, the height of the image plane is 7.0 mm, and the F-number is 1.7. [Table 15] Table 16 shows the aspherical values of the optical imaging system 800 according to the eighth embodiment of the present disclosure. [Table 16] Table 17 is a table showing the values related to conditional expressions 9 to 11 according to an embodiment of the present disclosure. [Table 17] Aspects of the present disclosure will provide an optical imaging system capable of obtaining a bright image while meeting high-resolution requirements. In summary, according to an embodiment of the present disclosure, the optical imaging system can provide a clear and bright image. Although specific examples have been shown and described above, it will be apparent after understanding the present disclosure that various changes in form and detail can be made to these examples without departing from the spirit and scope of the patent application scope and its equivalents. The examples described herein should be considered illustrative only and not for limiting purposes. The description of the features or aspects in each example should be considered applicable to similar features or aspects in other examples as well. Suitable results can be achieved if the techniques are implemented in a different order, and / or if the components in the system, architecture, device, or circuit are combined in a different manner and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of the present disclosure is not defined by the detailed description, but by the patent application scope and its equivalents, and all changes within the scope of the patent application scope and its equivalents should be construed as being included in the present disclosure. 100, 200, 300, 400, 500, 600, 700, 800: Optical imaging system 110, 210, 310, 410, 510, 610, 710, 810: First lens 120, 220, 320, 420, 520, 620, 720, 820: Second lens 130, 230, 330, 430, 530, 630, 730, 830: Third lens 140, 240, 340, 440, 540, 640, 740, 840: Fourth lens 150, 250, 350, 450, 550, 650, 750, 850: Fifth lens 160, 260, 360, 460, 560, 660, 760, 860: Sixth lens 170, 270, 370, 470, 570, 670, 770, 870: Seventh lens 180, 280, 380, 480, 580, 680, 780, 880: Infrared cut-off filter 190, 290, 390, 490, 590, 690, 790, 890: Image sensor FIG. 1 is a configuration diagram of an optical imaging system according to a first embodiment of the present disclosure. FIG. 2 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 1. FIG. 3 is a configuration diagram of an optical imaging system according to a second embodiment of the present disclosure. FIG. 4 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 3. FIG. 5 is a configuration diagram of an optical imaging system according to a third embodiment of the present disclosure. FIG. 6 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 5. FIG. 7 is a configuration diagram of an optical imaging system according to a fourth embodiment of the present disclosure. FIG. 8 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 7. FIG. 9 is a configuration diagram of an optical imaging system according to a fifth embodiment of the present disclosure. FIG. 10 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 9. FIG. 11 is a configuration diagram of an optical imaging system according to a sixth embodiment of the present disclosure. FIG. 12 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 11. FIG. 13 is a configuration diagram of an optical imaging system according to a seventh embodiment of the present disclosure. FIG. 14 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 13. FIG. 15 is a configuration diagram of an optical imaging system according to an eighth embodiment of the present disclosure. FIG. 16 is a graph showing the aberration characteristics of the optical imaging system shown in FIG. 15. In all the figures and throughout this detailed description, unless otherwise stated, the same reference numerals refer to the same elements. The figures may not be drawn to scale, and for clarity, illustration, and convenience, the relative sizes, proportions, and illustrations of the elements in the figures may be exaggerated. 100: Optical imaging system 110: First lens 120: Second lens 130: Third lens 140: Fourth lens 150: Fifth lens 160: Sixth lens 170: Seventh lens 180: Infrared cut-off filter 190: Image sensor

Claims

1. An optical imaging system, comprising: The first lens has a negative refractive force; Second lens; Third lens, having a convex image-side surface; Fourth lens; The fifth lens has a negative refractive force; A sixth lens has positive refractive power; and a seventh lens has a convex object-side surface. The optical imaging system has a total of seven lenses, which are arranged sequentially from the first lens to the seventh lens from the object side and satisfy the following conditions: TTL / IMH < 1.2, f / EPD < 1.8, and 50 < FOV / f (unit: degrees·mm⁻¹), where TTL is the distance on the optical axis from the object-side surface of the first lens to the image plane, IMH is half the diagonal length of the image plane, f is the focal length of the optical imaging system, EPD is the diameter of the entrance pupil, and FOV is the field of view of the optical imaging system.

2. The optical imaging system of claim 1, wherein the second lens has a positive refractive power and the image-side surface of the second lens is concave.

3. The optical imaging system as claimed in claim 1, wherein the object-side surface of the sixth lens is concave.

4. The optical imaging system of claim 1, wherein L6R1 / CT6 < -3, where L6R1 is the radius of curvature of the object-side surface of the sixth lens, and CT6 is the center thickness of the sixth lens.

5. The optical imaging system as claimed in claim 1, wherein 15 < v1-v2 < 40 and 0 < v1-v5 < 45, wherein v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, and v5 is the Abbe number of the fifth lens.

6. The optical imaging system of claim 1, wherein 1.6 < ET1 / CT1, where ET1 is the edge thickness of the first lens and CT1 is the center thickness of the first lens.

7. The optical imaging system of claim 1, wherein the object-side surface of the first lens is concave and the fourth lens has positive refractive power.

8. The optical imaging system of claim 1, wherein the image-side surface of the fifth lens is concave and the seventh lens has negative refractive power.

9. An optical imaging system, comprising: A first lens, wherein both the object-side surface and the image-side surface of the first lens are concave; a second lens; a third lens, having positive refractive power; The fourth lens has positive refractive power; Fifth lens; Sixth lens, with a concave object-side surface; The optical imaging system comprises a seventh lens having a convex object-side surface. The optical imaging system has a total of seven lenses, arranged sequentially from the first lens to the seventh lens from the object side. Any two or more surfaces of the first lens and the seventh lens, or any combination thereof, include one or more inflection points and satisfy the following condition: f / EPD < 1.8, and 50 < FOV / f (unit: degrees per millimeter). Here, f is the focal length of the optical imaging system, EPD is the diameter of the entrance pupil, and FOV is the field of view of the optical imaging system.

10. The optical imaging system of claim 9, wherein SD6 / SD14 < 0.5, wherein SD6 is the effective diameter of the image-side surface of the third lens and SD14 is the effective diameter of the image-side surface of the seventh lens.

11. The optical imaging system of claim 9, wherein the first lens has a negative refractive power and satisfies -4 < f1 / f < 0, where f1 is the focal length of the first lens.

12. The optical imaging system of claim 9, wherein the image-side surface of the fifth lens is convex and the seventh lens has positive refractive power.

13. The optical imaging system of claim 9, wherein the image-side surface of the fifth lens is concave and the seventh lens has negative refractive power.

14. The optical imaging system of claim 9, wherein TTL / IMH < 1.2, wherein TTL is the distance along the optical axis from the object-side surface of the first lens to the image plane, and IMH is half the diagonal length of the image plane.

Images