Optical image capturing system

Abstract

The optical image capturing system includes: a first lens having a positive refractive power, a convex object-side surface, and a concave image-side surface; a second lens having a negative refractive power, a convex object-side surface, and a concave image-side surface; a third lens having refractive power; a fourth lens having refractive power; a fifth lens having refractive power; a sixth lens having positive refractive power, a convex object-side surface, and a concave image-side surface; and a seventh lens having a negative refractive power, a convex object-side surface, and a concave image-side surface, in which the first to seventh lenses are sequentially disposed in a digital ascending order along an optical axis of the optical imaging system from the object-side surface of the optical imaging system toward the image-side surface of the image sensor, in which the optical imaging system has a total of seven lenses, a conditional expression 1.4 lt is satisfied; f23 / f1lt; 2.8 where f1 is the focal length of the first lens and f23 is the combined focal length of the second lens and the third lens.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2019-0020453, filed with the Korean Intellectual Property Office on February 21, 2019, and Korean Patent Application No. 10-2019-0091493, filed with the Korean Intellectual Property Office on July 29, 2019, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] This application relates to optical imaging systems. Background Technology

[0004] Recently, portable terminal devices have been designed to include cameras to allow for video calls and image capture. Furthermore, with the frequent use of camera functionality in portable terminal devices, the demand for high-resolution and high-performance cameras in these devices is constantly increasing.

[0005] However, with the size and weight of portable terminals already reduced, there are difficulties in realizing cameras with high resolution and high performance.

[0006] To address these issues, plastic materials, which are lighter than glass, have been used to manufacture camera lenses, and optical imaging systems have been designed to include five or six lenses to achieve high resolution. Summary of the Invention

[0007] The summary portion of this invention is intended to provide a brief overview of the chosen inventive concepts, which will be further described in the detailed description portion below. This summary portion is not intended to identify key or essential features of the claimed subject matter, nor to help determine the scope of the claimed subject matter.

[0008] In one general aspect, the optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in ascending numerical order along the optical axis of the optical imaging system from the object side of the optical imaging system toward the imaging surface of the image sensor, wherein the conditional expression f / f2+f / f3 < -0.4 can be satisfied, where f is the focal length of the optical imaging system, f2 is the focal length of the second lens, and f3 is the focal length of the third lens, and the conditional expression TTL / (2×IMG HT) < 0.69 can be satisfied, where TTL is the distance along the optical axis from the object side of the first lens to the imaging surface of the image sensor, and IMG HT is half the diagonal length of the imaging surface of the image sensor.

[0009] The condition expression n2+n3 > 3.15 can be satisfied, where n2 is the refractive index of the second lens and n3 is the refractive index of the third lens.

[0010] The condition expression n2+n3+n4 > 4.85 can be satisfied, where n4 is the refractive index of the fourth lens.

[0011] The conditional expression v1-v2 > 30 can be satisfied, where v1 is the Abbe number of the first lens and v2 is the Abbe number of the second lens.

[0012] The conditional expression 1.0 < TTL / f < 1.10 can be satisfied.

[0013] The conditional expression 0.15 < BFL / f < 0.25 can be satisfied, where BFL is the distance along the optical axis from the image-side surface of the seventh lens to the imaging surface of the image sensor.

[0014] The conditional expression 0.005 < D1 / f < 0.04 can be satisfied, where D1 is the distance along the optical axis between the image-side surface of the first lens and the object-side surface of the second lens.

[0015] The condition 0.30 < R1 / f < 0.40 can be satisfied, where R1 is the radius of curvature of the object side surface of the first lens.

[0016] The conditional expression 1.4 < |f23| / f1 < 2.8 can be satisfied, where f1 is the focal length of the first lens and f23 is the combined focal length of the second and third lenses.

[0017] The conditional expression Fno < 2.3 can be satisfied, where Fno is the F-number of the optical imaging system.

[0018] The refractive index of each of at least two of the first to seventh lenses may be 1.67 or greater.

[0019] The first lens may have positive refractive power, any one or both of the second and third lenses may have negative refractive power, and the refractive index of any one or both of the second and third lenses may be 1.67 or greater.

[0020] The first lens may have positive refractive power, and the seventh lens may have negative refractive power.

[0021] In another general aspect, the optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in ascending numerical order along the optical axis of the optical imaging system from the object side of the optical imaging system toward the imaging surface of the image sensor. The first lens has positive refractive power, and either or both of the second and third lenses have negative refractive power, satisfying the conditional expression n2+n3 > 3.15, where n2 is the refractive index of the second lens and n3 is the refractive index of the third lens, and satisfying the conditional expression TTL / (2×IMG HT) < 0.69, where TTL is the distance along the optical axis from the object side of the first lens to the imaging surface of the image sensor, and IMG HT is half the diagonal length of the imaging surface of the image sensor.

[0022] The conditional expression f / f2+f / f3 < -0.4 can be satisfied, where f is the focal length of the optical imaging system, f2 is the focal length of the second lens, and f3 is the focal length of the third lens.

[0023] It can satisfy the conditions v1-v2 > 30 and n2+n3+n4 > 4.85, where v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, and n4 is the refractive index of the fourth lens.

[0024] Other features and aspects will become apparent from the following detailed description, the accompanying drawings, and the appended claims. Attached Figure Description

[0025] Figure 1 This is a diagram illustrating a first example of an optical imaging system.

[0026] Figure 2 It is shown Figure 1 The diagram shows the aberration characteristics of the optical imaging system.

[0027] Figure 3 This is a diagram illustrating a second example of an optical imaging system.

[0028] Figure 4 It is shown Figure 3 The diagram shows the aberration characteristics of the optical imaging system.

[0029] Figure 5 This is a diagram illustrating a third example of an optical imaging system.

[0030] Figure 6 It is shown Figure 5 The diagram shows the aberration characteristics of the optical imaging system.

[0031] Figure 7 This is a diagram illustrating a fourth example of an optical imaging system.

[0032] Figure 8 It is shown Figure 7 The diagram shows the aberration characteristics of the optical imaging system.

[0033] Figure 9 This is a diagram illustrating the fifth example of an optical imaging system.

[0034] Figure 10 It is shown Figure 9 The diagram shows the aberration characteristics of the optical imaging system.

[0035] Throughout the accompanying drawings and detailed embodiments, the same reference numerals refer to the same elements. For purposes of clarity, illustration, and convenience, the drawings may not be drawn to scale, and the relative dimensions, scale, and depiction of elements in the drawings may be exaggerated. Detailed Implementation

[0036] The following detailed embodiments are provided to help readers gain a comprehensive understanding of the methods, apparatus, and / or systems described in this application. However, after understanding the disclosure of this application, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described in this application will be apparent. For example, the order of operations described in this application is merely illustrative and is not limited to the order set forth in this application, except for operations that must occur in a specific order, but can be changed as will become apparent after understanding the disclosure of this application. Furthermore, for clarity and conciseness, descriptions of features well-known in the art may be omitted.

[0037] The features described in this application may be implemented in different forms and should not be construed as being limited to the examples described in this application. Rather, the examples described in this application are provided merely to illustrate some of the many possible ways to implement the methods, apparatus, and / or systems described in this application, which will become apparent upon understanding the disclosure of this application.

[0038] The terminology used in this application is for describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the articles “a,” “an,” and “the” are intended to include the plural form as well. The terms “comprising,” “including,” and “having” describe 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.

[0039] In the accompanying drawings, for ease of illustration, the thickness, size, and shape of each lens of the optical imaging system may be exaggerated, and the spherical or aspherical shapes shown in the drawings are merely examples, and the shapes are not limited thereto.

[0040] The first lens of the optical imaging system is the lens closest to the object side of the optical imaging system, and the seventh lens of the optical imaging system is the lens closest to the image sensor of the optical imaging system.

[0041] The first surface (or object-side surface) of the lens is the object-side surface facing the optical imaging system, and the second surface (or image-side surface) of the lens is the surface facing the image sensor.

[0042] The radii of curvature of the component surfaces, the thickness of the components, the distance between the components, the distance between the surfaces of one component and another, the focal length, and the image height (IMG HT) are expressed in millimeters (mm), and the field of view (FOV) is expressed in degrees. Thickness and distance are measured along the optical axis of the optical imaging system.

[0043] The description of a lens surface as convex means that at least a paraxial region of the surface is convex; the description of a lens surface as concave means that at least a paraxial region of the surface is concave; and the description of a lens surface as flat means that at least a paraxial region of the surface is flat. Therefore, even when the surface of a lens is described as convex, the edge region of that surface may be concave. Furthermore, even when the surface of a lens is described as concave, the edge region of that surface may be convex. Additionally, even when the surface of a lens is described as flat, the edge region of that surface may be either convex or concave.

[0044] The paraxial region of a lens surface is the central part of the lens surface surrounding the optical axis, in which the angle between the light rays incident on the lens surface and the optical axis is a small angle θ, and approximately sin θ ≈ θ, tan θ ≈ θ, and cos θ ≈ 1 are valid.

[0045] An optical imaging system may include seven lenses.

[0046] For example, an 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 arranged in ascending numerical order along the optical axis of the optical imaging system from the object side of the optical imaging system toward the image side of the optical imaging system. The first to seventh lenses may be arranged to have a predetermined distance between them along the optical axis.

[0047] However, in addition to the seven lenses, an optical imaging system may include other components.

[0048] For example, an optical imaging system may also include an image sensor for converting an incident image of an object into an electrical signal.

[0049] Additionally, the optical imaging system may include an infrared filter (hereinafter referred to as the "filter") for blocking infrared light. The filter may be positioned between the seventh lens and the image sensor.

[0050] Additionally, the optical imaging system may include an aperture for adjusting the amount of light incident on the image sensor. The aperture can be positioned at any desired location.

[0051] The first through seventh lenses included in the optical imaging system can be made of plastic material.

[0052] Any one or any combination of two or more of the first to seventh lenses may have an aspherical surface. Alternatively, each of the first to seventh lenses may have at least one aspherical surface.

[0053] Any one or both of the first and second surfaces of each of the first to seventh lenses can be an aspherical surface defined by Equation 1 below.

[0054] (1)

[0055] In Equation 1, “c” is the curvature of the aspherical surface at the optical axis, and is equal to the reciprocal of the radius of curvature of the aspherical surface at the optical axis; “K” is the conic constant; “Y” is the distance from any point on the aspherical surface to the optical axis in the direction perpendicular to the optical axis; “A” to “H” and “J” are the aspherical coefficients of the aspherical surface; and “Z” is the distance from any point on the aspherical surface to a plane perpendicular to the optical axis and containing the vertex of the aspherical surface in the direction parallel to the optical axis.

[0056] In one example, the first to seventh lenses may have positive refractive power, negative refractive power, positive refractive power, positive refractive power, positive refractive power, positive refractive power, and negative refractive power, respectively.

[0057] In another example, the first to seventh lenses may have positive refractive power, positive refractive power, negative refractive power, positive refractive power, positive refractive power, positive refractive power, and negative refractive power, respectively.

[0058] In another example, the first to seventh lenses may have positive refractive power, negative refractive power, negative refractive power, positive refractive power, positive refractive power, positive refractive power, and negative refractive power, respectively.

[0059] In another example, the first to seventh lenses may have positive refractive power, negative refractive power, negative refractive power, positive refractive power, positive refractive power, negative refractive power, and negative refractive power, respectively.

[0060] In another example, the first to seventh lenses may have positive refractive power, negative refractive power, positive refractive power, negative refractive power, negative refractive power, positive refractive power, and negative refractive power, respectively.

[0061] Examples of optical imaging systems may satisfy any one or any combination of any two or more of the following conditional expressions 1 to 11.

[0062] f / f2 + f / f3 < -0.4 (Conditional expression 1)

[0063] v1-v2 > 30 (Conditional expression 2)

[0064] 1.0 < TTL / f < 1.10 (Conditional expression 3)

[0065] n² + n³ > 3.15 (Conditional expression 4)

[0066] 0.15 < BFL / f < 0.25 (Conditional expression 5)

[0067] 0.005 < D1 / f < 0.04 (Conditional expression 6)

[0068] 0.30 < R1 / f < 0.40 (Conditional expression 7)

[0069] TTL / (2×IMG HT) < 0.69 (Conditional expression 8)

[0070] Fno < 2.3 (Conditional expression 9)

[0071] n² + n³ + n⁴ > 4.85 (Conditional expression 10)

[0072] 1.4 < |f23| / f1 < 2.8 (Conditional expression 11)

[0073] In conditional expressions 1 to 11, "f" is the focal length of the optical imaging system, "f1" is the focal length of the first lens, "f2" is the focal length of the second lens, "f3" is the focal length of the third lens, "f23" is the combined focal length of the second and third lenses, "v1" is the Abbe number of the first lens, "v2" is the Abbe number of the second lens, "TTL" is the distance along the optical axis of the optical imaging system from the object-side surface of the first lens to the imaging surface of the image sensor, "n2" is the refractive index of the second lens, "n3" is the refractive index of the third lens, "n4" is the refractive index of the fourth lens, "BFL" is the distance along the optical axis from the image-side surface of the seventh lens to the imaging surface of the image sensor, "D1" is the distance along the optical axis between the image-side surface of the first lens and the object-side surface of the second lens, "R1" is the radius of curvature of the object-side surface of the first lens, "IMG HT" is half the diagonal length of the imaging surface of the image sensor, and "Fno" is the F-number of the optical imaging system.

[0074] In the following description, the first to seventh lenses of an example optical imaging system will be described.

[0075] The first lens may have positive refractive power. The first lens may have a meniscus shape that convexes toward the object side of the optical imaging system. In other words, the first surface of the first lens may be convex, and the second surface of the first lens may be concave.

[0076] Either or both of the first and second surfaces of the first lens can be aspherical. For example, both surfaces of the first lens can be aspherical.

[0077] The second lens may have positive or negative refractive power. The second lens may have a meniscus shape that convexes toward the object side of the optical imaging system. In other words, the first surface of the second lens may be convex, and the second surface of the second lens may be concave.

[0078] Either or both of the first and second surfaces of the second lens can be aspherical. For example, both surfaces of the second lens can be aspherical.

[0079] The third lens may have positive or negative refractive power. The third lens may have a meniscus shape that convexes towards the object side of the optical imaging system. In other words, the first surface of the third lens may be convex, and the second surface of the third lens may be concave.

[0080] Either or both of the first and second surfaces of the third lens can be aspherical. For example, both surfaces of the third lens can be aspherical.

[0081] At least one inflection point may be formed on either or both of the first and second surfaces of the third lens. For example, the first surface of the third lens may convex in the paraxial region of the first surface and concave in the edge region of the first surface.

[0082] The fourth lens may have positive or negative refractive power. The fourth lens may have a meniscus shape that convexes towards the object side of the optical imaging system. In other words, the first surface of the fourth lens may be convex, and the second surface of the fourth lens may be concave.

[0083] Alternatively, the first surface of the fourth lens may be flat in the paraxial region of the first surface, and the second surface may be convex.

[0084] Alternatively, both surfaces of the fourth lens can convex. In other words, the first and second surfaces of the fourth lens can convex.

[0085] Either or both of the first and second surfaces of the fourth lens can be aspherical. For example, both surfaces of the fourth lens can be aspherical.

[0086] At least one inflection point may be formed on either or both of the first and second surfaces of the fourth lens. For example, the second surface of the fourth lens may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0087] The fifth lens may have positive or negative refractive power. The fifth lens may have a meniscus shape that convexes toward the object side of the optical imaging system. In other words, the first surface of the fifth lens may convex in the paraxial region of the first surface, and the second surface of the fifth lens may be concave.

[0088] Alternatively, both surfaces of the fifth lens can convex. In other words, the first and second surfaces of the fifth lens can convex.

[0089] Alternatively, both surfaces of the fifth lens can be concave. In other words, the first and second surfaces of the fifth lens can be concave.

[0090] Either or both of the first and second surfaces of the fifth lens can be aspherical. For example, both surfaces of the fifth lens can be aspherical.

[0091] At least one inflection point may be formed on either or both of the first and second surfaces of the fifth lens. For example, the first surface of the fifth lens may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the fifth lens may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0092] The sixth lens can have either positive or negative refractive power. Both surfaces of the sixth lens can convex. In other words, the first and second surfaces of the sixth lens can convex in their respective paraxial regions.

[0093] The sixth lens may have a meniscus shape that convexes toward the image side of the optical imaging system. In other words, the first surface of the sixth lens may be concave in the paraxial region of the first surface, and the second surface of the sixth lens may convex in the paraxial region of the second surface.

[0094] Alternatively, the sixth lens may have a meniscus shape that convexes toward the object side of the optical imaging system. In other words, the first surface of the sixth lens may convex in the paraxial region of the first surface, and the second surface of the sixth lens may be concave in the paraxial region of the second surface.

[0095] Either or both of the first and second surfaces of the sixth lens can be aspherical. For example, both surfaces of the sixth lens can be aspherical.

[0096] At least one inflection point may be formed on either or both of the first and second surfaces of the sixth lens. For example, the first surface of the sixth lens may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the sixth lens may convex in the paraxial region of the second surface and concave in the edge region of the second surface.

[0097] The seventh lens can have negative refractive power. Both surfaces of the seventh lens can be concave. In other words, the first surface of the seventh lens can be concave in the paraxial region of the first surface, and the second surface of the seventh lens can be concave in the paraxial region of the second surface.

[0098] Alternatively, the seventh lens may have a meniscus shape that convexes toward the object side of the optical imaging system. In other words, the first surface of the seventh lens may convex in the paraxial region of the first surface, and the second surface of the seventh lens may be concave in the paraxial region of the second surface.

[0099] Either or both of the first and second surfaces of the seventh lens can be aspherical. For example, both surfaces of the seventh lens can be aspherical.

[0100] At least one inflection point may be formed on either or both of the first and second surfaces of the seventh lens. For example, the first surface of the seventh lens may be concave in the paraxial region of the first surface and convex in the edge region of the first surface. The second surface of the seventh lens may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0101] The first lens may be made of a first plastic material, and the second lens may be made of a second plastic material having optical properties different from those of the first plastic material.

[0102] The refractive index of at least one of the first to seventh lenses may be 1.67 or greater.

[0103] Additionally, the refractive index of each of at least two of the first to seventh lenses may be 1.67 or greater. For example, in one example, the refractive index of each of the three lenses from the first to the seventh lens may be 1.67 or greater, and in another example, the refractive index of each of the two lenses from the first to the seventh lens may be 1.67 or greater.

[0104] The refractive index of the lens with negative refractive power in the first through third lenses may be 1.67 or greater. As an example, any one or both of the second and third lenses may have negative refractive power and may have a refractive index of 1.67 or greater.

[0105] Examples of optical imaging systems having the first to seventh lenses configured as described above have improved aberration characteristics.

[0106] Figure 1 This is a diagram illustrating a first example of an optical imaging system, and Figure 2 It is shown Figure 1 The diagram shows the aberration characteristics of the optical imaging system.

[0107] The optical imaging system of the first example 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, and may also include an aperture (not shown), a filter 180 and an image sensor 190.

[0108] The following table 1 lists Figure 1 The characteristics of the elements shown include the radius of curvature of the element's surface, the element's thickness, the distance between elements, the element's refractive index, the element's Abbe number, and the element's focal length.

[0109] Table 1

[0110] In the first example, the focal length f of the optical imaging system is 5.744 mm, Fno is 2.01, FOV is 77.23°, BFL is 0.909 mm, TTL is 6.201 mm, and IMG HT is 4.56 mm.

[0111] Fno is a numerical value representing the brightness of the optical imaging system, and is equal to the effective focal length of the optical imaging system divided by the entrance pupil diameter of the optical imaging system. FOV is the field of view of the optical imaging system. BFL is the distance along the optical axis of the optical imaging system from the image side of the seventh lens to the imaging surface of the image sensor. TTL is the distance along the optical axis from the object side of the first lens to the imaging surface of the image sensor. IMG HT is half the diagonal length of the imaging surface of the image sensor.

[0112] In the first example, the first lens 110 may have positive refractive power, the first surface of the first lens 110 may be convex, and the second surface of the first lens 110 may be concave.

[0113] The second lens 120 may have negative refractive power, the first surface of the second lens 120 may be convex, and the second surface of the second lens 120 may be concave.

[0114] The third lens 130 may have positive refractive power, the first surface of the third lens 130 may convex in the paraxial region of the first surface, and the second surface of the third lens 130 may be concave in the paraxial region of the second surface.

[0115] At least one inflection point may be formed on either or both of the first and second surfaces of the third lens 130. For example, the first surface of the third lens 130 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the third lens 130 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0116] The fourth lens 140 may have positive refractive power, the first surface of the fourth lens 140 may be convex, and the second surface of the fourth lens 140 may be concave.

[0117] The fifth lens 150 may have positive refractive power, the first surface of the fifth lens 150 may convex in the paraxial region of the first surface, and the second surface of the fifth lens 150 may be concave in the paraxial region of the second surface.

[0118] At least one inflection point may be formed on either or both of the first and second surfaces of the fifth lens 150. For example, the first surface of the fifth lens 150 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the fifth lens 150 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0119] The sixth lens 160 may have positive refractive power, and the first and second surfaces of the sixth lens 160 may be convex.

[0120] At least one inflection point may be formed on either or both of the first and second surfaces of the sixth lens 160. For example, the first surface of the sixth lens 160 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the sixth lens 160 may convex in the paraxial region of the second surface and concave in the edge region of the second surface.

[0121] The seventh lens 170 may have negative refractive power, and the first surface of the seventh lens 170 may be concave in the paraxial region of the first surface, and the second surface of the seventh lens 170 may be concave in the paraxial region of the second surface.

[0122] At least one inflection point may be formed on either or both of the first and second surfaces of the seventh lens 170. For example, the first surface of the seventh lens 170 may be concave in the paraxial region of the first surface and convex in the edge region of the first surface. The second surface of the seventh lens 170 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0123] The surfaces of the first lens 110 to the seventh lens 170 may have aspheric coefficients listed in Table 2 below. For example, each of the object-side surface and the image-side surface of each of the first lens 110 to the seventh lens 170 may be aspherical.

[0124] Table 2

[0125] Figure 1 The first example of the optical imaging system shown, configured according to Tables 1 and 2 above, may have: Figure 2 The aberration characteristics shown are illustrated.

[0126] Figure 3 This is a diagram illustrating a second example of an optical imaging system, and Figure 4 It is shown Figure 3 The diagram shows the aberration characteristics of the optical imaging system.

[0127] The optical imaging system of the second example 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, and may also include an aperture (not shown), a filter 280 and an image sensor 290.

[0128] The following table 3 lists... Figure 3 The characteristics of the elements shown include the radius of curvature of the element's surface, the element's thickness, the distance between elements, the element's refractive index, the element's Abbe number, and the element's focal length.

[0129] Table 3

[0130] In the second example, the focal length f of the optical imaging system is 6.000 mm, Fno is 2.18, FOV is 72.96°, BFL is 0.908 mm, TTL is 6.202 mm, and IMG HT is 4.56 mm.

[0131] The definitions of Fno, FOV, BFL, TTL, and IMG HT are the same as in the first example.

[0132] In the second example, the first lens 210 may have positive refractive power, the first surface of the first lens 210 may be convex, and the second surface of the first lens 210 may be concave.

[0133] The second lens 220 may have positive refractive power, the first surface of the second lens 220 may be convex, and the second surface of the second lens 220 may be concave.

[0134] The third lens 230 may have negative refractive power, the first surface of the third lens 230 may be convex, and the second surface of the third lens 230 may be concave.

[0135] The fourth lens 240 may have positive refractive power, the first surface of the fourth lens 240 may convex in the paraxial region of the first surface, and the second surface of the fourth lens 240 may be concave in the paraxial region of the second surface.

[0136] At least one inflection point may be formed on either or both of the first and second surfaces of the fourth lens 240. For example, the first surface of the fourth lens 240 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the fourth lens 240 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0137] The fifth lens 250 may have positive refractive power, the first surface of the fifth lens 250 may convex in the paraxial region of the first surface, and the second surface of the fifth lens 250 may be concave in the paraxial region of the second surface.

[0138] At least one inflection point may be formed on either or both of the first and second surfaces of the fifth lens 250. For example, the first surface of the fifth lens 250 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the fifth lens 250 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0139] The sixth lens 260 may have positive refractive power, and the first surface of the sixth lens 260 may bulge in the paraxial region of the first surface, and the second surface of the sixth lens 260 may bulge in the paraxial region of the second surface.

[0140] At least one inflection point may be formed on either or both of the first and second surfaces of the sixth lens 260. For example, the first surface of the sixth lens 260 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the sixth lens 260 may convex in the paraxial region of the second surface and concave in the edge region of the second surface.

[0141] The seventh lens 270 may have negative refractive power, and the first surface of the seventh lens 270 may be concave in the paraxial region of the first surface, and the second surface of the seventh lens 270 may be concave in the paraxial region of the second surface.

[0142] At least one inflection point may be formed on either or both of the first and second surfaces of the seventh lens 270. For example, the first surface of the seventh lens 270 may be concave in the paraxial region of the first surface and convex in the edge region of the first surface. The second surface of the seventh lens 270 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0143] The surfaces of the first lens 210 through the seventh lens 270 may have aspheric coefficients listed in Table 4 below. For example, each of the object-side surface and the image-side surface of each of the first lens 210 through the seventh lens 270 may be aspherical.

[0144] Table 4

[0145] Figure 3 The second example of the optical imaging system shown, configured according to Tables 3 and 4 above, may have... Figure 4 The aberration characteristics shown are illustrated.

[0146] Figure 5 This is a diagram illustrating a third example of an optical imaging system, and Figure 6 It is shown Figure 5 The diagram shows the aberration characteristics of the optical imaging system.

[0147] The optical imaging system of the third example 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, and may also include an aperture, a filter 380 and an image sensor 390.

[0148] The following table 5 lists... Figure 5 The characteristics of the elements shown include the radius of curvature of the element's surface, the element's thickness, the distance between elements, the element's refractive index, the element's Abbe number, and the element's focal length.

[0149] Table 5

[0150] In the third example, the focal length f of the optical imaging system is 6.000 mm, Fno is 2.14, FOV is 73.59°, BFL is 1.234 mm, TTL is 6.200 mm, and IMG HT is 4.56 mm.

[0151] The definitions of Fno, FOV, BFL, TTL, and IMG HT are the same as in the first example.

[0152] In the third example, the first lens 310 may have positive refractive power, the first surface of the first lens 310 may be convex, and the second surface of the first lens 310 may be concave.

[0153] The second lens 320 may have negative refractive power, the first surface of the second lens 320 may be convex, and the second surface of the second lens 320 may be concave.

[0154] The third lens 330 may have negative refractive power, the first surface of the third lens 330 may convex in the paraxial region of the first surface, and the second surface of the third lens 330 may be concave in the paraxial region of the second surface.

[0155] At least one inflection point may be formed on either or both of the first and second surfaces of the third lens 330. For example, the first surface of the third lens 330 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the third lens 330 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0156] The fourth lens 340 may have positive refractive power, the first surface of the fourth lens 340 may be flat in the paraxial region of the first surface, and the second surface of the fourth lens 340 may be convex in the paraxial region of the second surface.

[0157] At least one inflection point may be formed on either or both of the first and second surfaces of the fourth lens 340. For example, the first surface of the fourth lens 340 may be flat in the paraxial region of the first surface and may be convex in the edge region of the first surface.

[0158] The fifth lens 350 may have positive refractive power, and the first and second surfaces of the fifth lens 350 may be convex.

[0159] The sixth lens 360 may have positive refractive power, the first surface of the sixth lens 360 may be concave, and the second surface of the sixth lens 360 may be convex.

[0160] The seventh lens 370 may have negative refractive power, and the first surface of the seventh lens 370 may be concave in the paraxial region of the first surface, and the second surface of the seventh lens 370 may be concave in the paraxial region of the second surface.

[0161] At least one inflection point may be formed on either or both of the first and second surfaces of the seventh lens 370. For example, the first surface of the seventh lens 370 may be concave in the paraxial region of the first surface and convex in the edge region of the first surface. The second surface of the seventh lens 370 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0162] The surfaces of the first lens 310 to the seventh lens 370 may have aspheric coefficients listed in Table 6 below. For example, each of the object-side surface and the image-side surface of each of the first lens 310 to the seventh lens 370 may be aspherical.

[0163] Table 6

[0164] Figure 5 The third example of the optical imaging system shown, configured according to Tables 5 and 6 above, may have... Figure 6 The aberration characteristics shown are illustrated.

[0165] Figure 7 This is a diagram illustrating a fourth example of an optical imaging system, and Figure 8 It is shown Figure 7 The diagram shows the aberration characteristics of the optical imaging system.

[0166] The optical imaging system of the fourth example 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, and may also include an aperture, a filter 480 and an image sensor 490.

[0167] The following table 7 lists... Figure 7 The characteristics of the elements shown include the radius of curvature of the element's surface, the element's thickness, the distance between elements, the element's refractive index, the element's Abbe number, and the element's focal length.

[0168] Table 7

[0169] In the fourth example, the focal length f of the optical imaging system is 6.000 mm, Fno is 2.20, FOV is 74.55°, BFL is 1.196 mm, TTL is 6.200 mm, and IMG HT is 4.56 mm.

[0170] The definitions of Fno, FOV, BFL, TTL, and IMG HT are the same as in the first example.

[0171] In the fourth example, the first lens 410 may have positive refractive power, the first surface of the first lens 410 may be convex, and the second surface of the first lens 410 may be concave.

[0172] The second lens 420 may have negative refractive power, the first surface of the second lens 420 may be convex, and the second surface of the second lens 420 may be concave.

[0173] The third lens 430 may have negative refractive power, the first surface of the third lens 430 may convex in the paraxial region of the first surface, and the second surface of the third lens 430 may be concave.

[0174] At least one inflection point may be formed on either or both of the first and second surfaces of the third lens 430. For example, the first surface of the third lens 430 may convex in the paraxial region of the first surface and concave in the edge region of the first surface.

[0175] The fourth lens 440 may have positive refractive power, and the first and second surfaces of the fourth lens 440 may be convex.

[0176] The fifth lens 450 may have positive refractive power, and the first and second surfaces of the fifth lens 450 may be convex.

[0177] The sixth lens 460 may have negative refractive power, the first surface of the sixth lens 460 may be concave, and the second surface of the sixth lens 460 may be convex.

[0178] The seventh lens 470 may have negative refractive power, and the first surface of the seventh lens 470 may be concave in the paraxial region of the first surface, and the second surface of the seventh lens 470 may be concave in the paraxial region of the second surface.

[0179] At least one inflection point may be formed on either or both of the first and second surfaces of the seventh lens 470. For example, the first surface of the seventh lens 470 may be concave in the paraxial region of the first surface and convex in the edge region of the first surface. The second surface of the seventh lens 470 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0180] The surfaces of the first lens 410 to the seventh lens 470 may have aspheric coefficients listed in Table 8 below. For example, each of the object-side surface and the image-side surface of each of the first lens 410 to the seventh lens 470 may be aspherical.

[0181] Table 8

[0182] Figure 7 The fourth example of the optical imaging system shown, configured according to Tables 7 and 8 above, may have... Figure 8 The aberration characteristics shown are illustrated.

[0183] Figure 9 This is a diagram illustrating a fifth example of an optical imaging system, and Figure 10 It is shown Figure 9 The diagram shows the aberration characteristics of the optical imaging system.

[0184] The optical imaging system of the fifth example 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, and may also include an aperture, a filter 580 and an image sensor 590.

[0185] The following table 9 lists... Figure 9 The characteristics of the elements shown include the radius of curvature of the element's surface, the element's thickness, the distance between elements, the element's refractive index, the element's Abbe number, and the element's focal length.

[0186] Table 9

[0187] In the fifth example, the focal length f of the optical imaging system is 5.870 mm, Fno is 2.27, FOV is 75.52°, BFL is 0.965 mm, TTL is 6.197 mm, and IMG HT is 4.62 mm.

[0188] The definitions of Fno, FOV, BFL, TTL, and IMG HT are the same as in the first example.

[0189] In the fifth example, the first lens 510 may have positive refractive power, the first surface of the first lens 510 may be convex, and the second surface of the first lens 510 may be concave.

[0190] The second lens 520 may have negative refractive power, the first surface of the second lens 520 may be convex, and the second surface of the second lens 520 may be concave.

[0191] The third lens 530 may have positive refractive power, the first surface of the third lens 530 may be convex, and the second surface of the third lens 530 may be concave.

[0192] The fourth lens 540 may have negative refractive power, the first surface of the fourth lens 540 may convex in the paraxial region of the first surface, and the second surface of the fourth lens 540 may be concave in the paraxial region of the second surface.

[0193] At least one inflection point may be formed on either or both of the first and second surfaces of the fourth lens 540. For example, the first surface of the fourth lens 540 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the fourth lens 540 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0194] The fifth lens 550 may have negative refractive power, and the first surface of the fifth lens 550 may be concave, and the second surface of the fifth lens 550 may be concave.

[0195] The sixth lens 560 may have positive refractive power, the first surface of the sixth lens 560 may convex in the paraxial region of the first surface, and the second surface of the sixth lens 560 may be concave in the paraxial region of the second surface.

[0196] At least one inflection point may be formed on either or both of the first and second surfaces of the sixth lens 560. For example, the first surface of the sixth lens 560 may convex in the paraxial region of the first surface and concave in the edge region of the first surface. The second surface of the sixth lens 560 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0197] The seventh lens 570 may have negative refractive power, the first surface of the seventh lens 570 may convex in the paraxial region of the first surface, and the second surface of the seventh lens 570 may be concave in the paraxial region of the second surface.

[0198] At least one inflection point may be formed on either or both of the first and second surfaces of the seventh lens 570. For example, the second surface of the seventh lens 570 may be concave in the paraxial region of the second surface and convex in the edge region of the second surface.

[0199] The surfaces of the first lens 510 to the seventh lens 570 may have aspheric coefficients listed in Table 10 below. For example, each of the object-side surface and the image-side surface of each of the first lens 510 to the seventh lens 570 may be aspherical.

[0200] Table 10

[0201] Figure 9 The fifth example of the optical imaging system shown, configured according to Tables 9 and 10 above, may have Figure 10 The aberration characteristics shown are illustrated.

[0202] Table 11 below lists the values ​​of conditional expressions 1 to 11 in the first through fifth examples.

[0203] Table 11

[0204] Based on the above example, an optical imaging system can have a reduced size and an increased focal length. The increased focal length enables the optical imaging system to have high resolution.

[0205] While this disclosure includes specific examples, it will be apparent upon understanding the disclosure of this application that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein should be considered descriptive only and not for limiting purposes. Descriptions of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Suitable results may also be obtained if the described techniques are performed in a different order, and / or if components in the described system, architecture, device, or circuit are combined in different ways and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of this disclosure should not be limited by the specific embodiments but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included in this disclosure.

Claims

1. An optical imaging system, comprising: The first lens has positive refractive power, a convex object-side surface, and a concave image-side surface; The second lens has negative refractive power, a convex object side, and a concave image side; The third lens has refractive power; The fourth lens has refractive power; The fifth lens has refractive power; The sixth lens has positive refractive power, a convex object-side surface, and a concave image-side surface; as well as The seventh lens has negative refractive power, a convex object-side surface, and a concave image-side surface. The first lens to the seventh lens are arranged in ascending numerical order along the optical axis of the optical imaging system from the object side of the optical imaging system toward the imaging surface of the image sensor. The optical imaging system has a total of seven lenses. The condition 1.4 < |f23| / f1 < 2.8 is satisfied, where f1 is the focal length of the first lens and f23 is the combined focal length of the second and third lenses.

2. The optical imaging system according to claim 1, wherein, The condition expression -0.89 ≤ f / f2+f / f3 <-0.4 is satisfied, where f is the focal length of the optical imaging system, f2 is the focal length of the second lens, and f3 is the focal length of the third lens.

3. The optical imaging system according to claim 1, wherein, The condition 30 < v1 - v2 ≤ 44.35 is satisfied, where v1 is the Abbe number of the first lens and v2 is the Abbe number of the second lens.

4. The optical imaging system according to claim 1, wherein, The condition 3.15 < n2 + n3 ≤ 3.37 is satisfied, where n2 is the refractive index of the second lens and n3 is the refractive index of the third lens.

5. The optical imaging system according to claim 1, wherein, The condition 4.85 < n2+n3+n4 ≤ 5.04 is satisfied, where n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, and n4 is the refractive index of the fourth lens.

6. The optical imaging system according to claim 1, wherein, The conditional expression 0.15 < BFL / f < 0.25 is satisfied, where BFL is the distance along the optical axis from the image-side surface of the seventh lens to the imaging surface of the image sensor, and f is the focal length of the optical imaging system.

7. The optical imaging system according to claim 1, wherein, The condition expression Fno < 2.3 is satisfied, where Fno is the F-number of the optical imaging system.

8. The optical imaging system according to claim 1, wherein, The condition 0.005 < D1 / f < 0.04 is satisfied, where f is the focal length of the optical imaging system and D1 is the distance along the optical axis between the image-side surface of the first lens and the object-side surface of the second lens.

9. The optical imaging system according to claim 1, wherein, The conditional expression 1.0 < TTL / f < 1.10 is satisfied, where TTL is the distance along the optical axis from the object side of the first lens to the imaging surface of the image sensor, and f is the focal length of the optical imaging system.

10. The optical imaging system according to claim 1, wherein, The conditional expression TTL / (2×IMG HT) < 0.69 is satisfied, where TTL is the distance along the optical axis from the object side of the first lens to the imaging surface of the image sensor, and IMG HT is half the diagonal length of the imaging surface of the image sensor.

11. The optical imaging system according to claim 1, wherein, The condition 0.30 < R1 / f < 0.40 is satisfied, where R1 is the radius of curvature of the object side surface of the first lens, and f is the focal length of the optical imaging system.

12. The optical imaging system according to claim 1, wherein, The third lens has a convex object-side surface and a concave image-side surface.

13. The optical imaging system according to claim 1, wherein, The fourth lens has a convex object-side surface.

14. The optical imaging system according to claim 1, wherein, The fifth lens has a concave image-side surface.

15. The optical imaging system according to claim 1, wherein, The refractive index of each of at least two lenses from the first lens to the seventh lens is 1.67 or higher.

16. The optical imaging system according to claim 1, wherein, The refractive index of either the second lens or the third lens, or each of the two lenses, is 1.67 or higher.

17. The optical imaging system according to claim 1, wherein, Each of the object-side surface and the image-side surface of each of the first to the seventh lenses is aspherical.

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