Optical imaging system

Abstract

The present application provides an optical imaging system, comprising: a first lens comprising positive refractive power; a second lens comprising positive refractive power; a third lens comprising negative refractive power; a fourth lens comprising positive refractive power; a fifth lens comprising negative refractive power; and a sixth lens comprising positive refractive power, wherein the first lens to the sixth lens are sequentially arranged from an object side to an imaging surface, wherein the optical imaging system comprises a total of six lenses having refractive power, wherein the focal length of the second lens is in the range of 5.0mm to 8.0mm, wherein 0.7<TL / f<1.0, wherein TL is the distance from the object side surface of the first lens to the imaging surface, and f is the total focal length of the optical imaging system.

Description

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2018-0063714, filed June 1, 2018, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety for all purposes. TECHNICAL FIELD

[0002] The present disclosure relates to a telephoto optical imaging system including six lenses. BACKGROUND

[0003] A telephoto optical system capable of long distance imaging has a considerable size. For example, a total length TL of an optical system of the telephoto optical system is 1 or more than 1 with respect to a total focal length f (TL / f = 1 or more). Accordingly, it is difficult to mount the telephoto optical system in a small electronic device such as a portable terminal. In addition, for the telephoto optical system, it can be difficult to secure sufficient light quantity incident on an imaging plane, so that it can be difficult to implement a low F number (F No.). SUMMARY

[0004] The following presents a summary to provide a basic understanding of some aspects of the application. This summary is not intended to identify key / critical features of the subject matter or determine the scope of the subject matter. Its sole purpose is to present some concepts of the application in a simplified form as a prelude to the more detailed description that is presented in the following.

[0005] In one general aspect, an optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens disposed in order from an object side toward an image side, the third lens including a concave object side surface. The optical imaging system satisfies 0.7 < TL / f < 1.0 and F No. < 2.1, where TL is a distance from an object side surface of the first lens to an imaging plane, f is a total focal length of the optical imaging system, and F No. is an F number of the optical imaging system.

[0006] A sign of a refractive power of the second lens can be the same as a sign of a refractive power of the first lens.

[0007] A sign of a refractive power of the third lens can be different from a sign of a refractive power of the first lens.

[0008] A sign of a refractive power of the fifth lens can be the same as a sign of a refractive power of the third lens.

[0009] The sixth lens can have a positive refractive power.

[0010] The second lens can include a convex object side surface.

[0011] The fifth lens can include a convex object side surface.

[0012] The optical imaging system can satisfy D45 / TL < 0.18, where D45 is a distance from an image side surface of the fourth lens to an object side surface of the fifth lens.

[0013] The optical imaging system satisfies r1 / r4 < 0.1, where r1 is a radius of curvature of an object side surface of the first lens, and r4 is a radius of curvature of an image side surface of the second lens.

[0014] In another general aspect, an optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens disposed in order from an object side to an image side. The optical imaging system satisfies 0.7 < TL / f < 1.0 and F No. < 2.1, where TL is a distance from an object side surface of the first lens to an image plane, f is a total focal length of the optical imaging system, and F No. is an F number of the optical imaging system.

[0015] The second lens can have a positive refractive power.

[0016] The third lens can have a negative refractive power.

[0017] A sign of a refractive power of the fifth lens can be different from a sign of a refractive power of the second lens.

[0018] The second lens can include a convex object side surface.

[0019] The optical imaging system can satisfy 1.2 < r2 / r3, where r2 is a radius of curvature of an image side surface of the first lens, and r3 is a radius of curvature of an object side surface of the second lens.

[0020] The optical imaging system can satisfy 5.0 < D56 / D12, where D12 is a distance from an image side surface of the first lens to an object side surface of the second lens, and D56 is a distance from an image side surface of the fifth lens to an object side surface of the sixth lens.

[0021] In another general aspect, an optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens disposed in order from an object side to an image side. The first lens has a positive refractive power, and the third lens includes a concave object side surface.

[0022] The optical imaging system can satisfy 0.7 < TL / f < 1.0 and F No. < 2.1, where TL is a distance from an object side surface of the first lens to an image plane, f is a total focal length of the optical imaging system, and F No. is an F number of the optical imaging system.

[0023] The sixth lens can include a convex image side surface.

[0024] The sixth lens can include a convex image side surface.

[0025] Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a configuration diagram of an optical imaging system according to an example.

[0027] Figure 2 is a configuration diagram of an optical imaging system according to an example. Figure 1 is a configuration diagram of an optical imaging system according to an example.

[0028] Figure 3 is a configuration diagram of an optical imaging system according to an example.

[0029] Figure 4 is a configuration diagram of an optical imaging system according to an example. Figure 3 is a configuration diagram of an optical imaging system according to an example.

[0030] Figure 5 is a configuration diagram of an optical imaging system according to an example.

[0031] Figure 6 is a configuration diagram of an optical imaging system according to an example. Figure 5 is a configuration diagram of an optical imaging system according to an example.

[0032] In all of the drawings and specific embodiments, like reference numerals indicate like elements. The drawings can not be to scale and the relative dimensions, proportions, and depiction of elements in the drawings can be exaggerated for clarity, illustration, and convenience. DETAILED DESCRIPTION

[0033] The following detailed description is provided to help the reader obtain a thorough understanding of the methods, devices, and / or systems described herein. However, the methods, devices, and / or systems described herein can be implemented in various ways, and the following detailed description is not intended to limit the methods, devices, and / or systems described herein to the ways described herein. For example, the order in which the operations are described is merely exemplary and is not intended to be limiting, except where the order of operations is essential to the particular operation being performed. Furthermore, the description of the features of the methods, devices, and / or systems described herein can be omitted in order to improve clarity and brevity.

[0034] The features described herein can be implemented in different ways depending upon the implementation. Rather than be bound by the examples described herein, it is to be understood that the examples have been provided for the purpose of illustrating some of the many possible ways of implementing the methods, devices, and / or systems described herein.

[0035] In this document, the use of the term "may" in relation to examples or embodiments (e.g., with respect to what an example or embodiment can include or implement) means that at least one example or embodiment includes or implements the feature, and that no example or embodiment excludes the feature.

[0036] Throughout the specification, when an element (such as a layer, region, or substrate) is referred to as being "on" another element, "connected to" another element, or "coupled to" another element, it can be directly on, connected, or coupled to the other element, or one or more other elements can be interposed therebetween. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no other elements interposed therebetween.

[0037] As used herein, the term "and / or" includes any one of the listed items and any combination of two or more of the listed items.

[0038] Although terms such as "first", "second", and "third" can be used herein to describe various components, assemblies, regions, layers, or sections, these components, assemblies, regions, layers, or sections are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or section from another component, assembly, region, layer, or section. Thus, the first component, assembly, region, layer, or section described in the examples described herein can also be referred to as the second component, assembly, region, layer, or section without departing from the teachings of the examples.

[0039] For ease of description, spatial terms, such as "above", "upper", "below", and "lower" can be used herein with respect to the orientation of one element relative to another element as depicted in the figures. Such spatial 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, then a component described as above relative to another component would now be below relative to the other component. Accordingly, the term "above" encompasses both a "above" and "below" orientation depending on the spatial orientation of the device. The device can be oriented in other ways (e.g., rotated 90 degrees or at other orientations) and an appropriate reorientation of the spatial terms will encompass those other orientations as well.

[0040] The terminology used herein is for the purpose of describing various examples only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has", "having" as used herein, are specifically intended to be construed as open-ended terms (i.e., the terms do not exclude additional, unrecited elements).

[0041] Due to manufacturing techniques and / or tolerances, variations of the shapes illustrated in the figures can occur. Therefore, the examples described herein are not limited to the specific shapes illustrated in the figures, but include deviations in shapes that occur in manufacturing processes.

[0042] Features of the examples described herein can be combined with each other as would be apparent to one of ordinary skill in the art after having the benefit of the present disclosure. Furthermore, while examples herein can have various configurations, other configurations are possible as would be apparent to one of ordinary skill in the art after having the benefit of the present disclosure.

[0043] In the disclosure, the first lens refers to a lens closest to an object (or a subject), and the sixth lens refers to a lens closest to an imaging surface (or an image sensor). In the disclosure, a radius of curvature, a thickness, an IMG HT (1 / 2 of a diagonal length of an imaging surface), and a focal length of a lens are each expressed in millimeters (mm). Also, the thickness of a lens, a gap between lenses, and a TL (a distance from an object-side surface of the first lens to the imaging surface) are distances measured based on an optical axis of the lens. Also, in a description of a shape of a lens, a convex of one surface of the lens means a convex of an optical axis portion of the corresponding surface, and a concave of one surface of the lens means a concave of an optical axis portion of the corresponding surface. Accordingly, even in a case where one surface of a lens is described as having a convex shape, an edge portion of the one surface of the lens can be concave. Likewise, even in a case where one surface of a lens is described as having a concave shape, an edge portion of the one surface of the lens can be convex.

[0044] The optical imaging system includes six lenses. For example, the optical imaging system can include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens disposed in order from an object side toward an image side. An air gap is disposed between the first lens to the sixth lens. For example, an object-side surface of any lens does not contact an image-side surface of an adjacent lens, and an image-side surface of any lens does not contact an object-side surface of an adjacent lens.

[0045] The first lens has a refractive power. For example, the first lens has a positive refractive power. The first lens has a concave shape on one surface. For example, the first lens can have a concave image-side surface.

[0046] The first lens includes an aspheric surface. For example, both surfaces of the first lens can be aspheric. The first lens can be made of a material having high light transmittance and excellent machinability. For example, the first lens can be made of a plastic material. However, the material of the first lens is not limited to a plastic material. The first lens has a relatively low refractive index than the refractive indexes of the other lenses. For example, the refractive index of the first lens can be 1.6 or less.

[0047] The second lens has a refractive power. For example, the sign of the refractive power of the second lens can be the same as the sign of the refractive power of the first lens. The second lens can have a convex shape on one surface. For example, the second lens can have a convex object-side surface.

[0048] The second lens includes an aspherical surface. For example, both surfaces of the second lens can be aspherical. The second lens can be made of a material having high light transmittance and excellent machinability. For example, the second lens can be made of a plastic material. However, the material of the second lens is not limited to plastic. For example, the second lens can also be made of a glass material. The second lens has a refractive index substantially similar to that of the first lens. For example, the refractive index of the second lens is 1.6 or less.

[0049] The third lens has a refractive power. For example, the sign of the refractive power of the third lens can be different from that of the first and second lenses. The third lens has a concave shape on one surface. For example, the third lens can have a concave shape on the object side surface.

[0050] The third lens can include an aspherical surface. For example, both surfaces of the third lens can be aspherical. The third lens can be made of a material having high light transmittance and excellent machinability. For example, the third lens can be made of a plastic material. However, the material of the third lens is not limited to plastic. For example, the third lens can be made of a glass material. The third lens can have a refractive index higher than that of the first lens. For example, the refractive index of the third lens can be 1.6 or more.

[0051] The fourth lens has a refractive power. For example, the fourth lens has a positive refractive power. The fourth lens has a convex shape on one surface. For example, the fourth lens can have a convex shape on the image side surface. The fourth lens can include an aspherical surface. For example, both surfaces of the fourth lens can be aspherical.

[0052] The fourth lens can be made of a material having high light transmittance and excellent machinability. For example, the fourth lens can be made of a plastic material. However, the material of the fourth lens is not limited to plastic. For example, the fourth lens can be made of a glass material. The fourth lens can have a refractive index higher than that of the first lens. For example, the refractive index of the fourth lens can be 1.6 or more.

[0053] The fifth lens has a refractive power. For example, the sign of the refractive power of the fifth lens is different from that of the second lens. In addition, the sign of the refractive power of the fifth lens can be the same as that of the third lens. The fifth lens has a convex shape on one surface. For example, the fifth lens can have a convex object side surface.

[0054] The fifth lens includes an aspherical surface. For example, both surfaces of the fifth lens can be aspherical. The fifth lens can be made of a material having high light transmittance and excellent machinability. For example, the fifth lens can be made of a plastic material. However, the material of the fifth lens is not limited to plastic. For example, the fifth lens can be made of a glass material. The fifth lens has a refractive index substantially similar to that of the first lens. For example, the refractive index of the fifth lens is 1.6 or less.

[0055] The sixth lens has a refractive power. For example, the sixth lens can have a positive refractive power. The sixth lens can have a convex shape on one surface. For example, the sixth lens can have a convex object side surface.

[0056] The sixth lens includes an aspherical surface. For example, both surfaces of the sixth lens can be aspherical. The sixth lens can be made of a material having high light transmittance and excellent machinability. For example, the sixth lens can be made of a plastic material. However, the material of the sixth lens is not limited to plastic. For example, the sixth lens can be made of a glass material. The sixth lens has a refractive index higher than that of the first lens. For example, the refractive index of the sixth lens can be 1.6 or more.

[0057] The aspherical surfaces of the first lens to the sixth lens can be represented by the following Equation 1:

[0058] [Equation 1]

[0059]

[0060] where c is the reciprocal of the radius of curvature of the lens, k is the conic constant, r is the distance from any point on the aspherical surface to the optical axis in a direction perpendicular to the optical axis, A to H and J are aspherical coefficients, and Z (or SAG) is the distance in the direction of the optical axis from the vertex of the aspherical surface to any point on the aspherical surface at a distance r from the optical axis.

[0061] The optical imaging system includes a filter, an image sensor, and a stop. The filter is disposed between the sixth lens and the image sensor. The filter can block light of certain wavelengths. For example, the filter can block light of infrared wavelengths. The image sensor forms an imaging surface. For example, the surface of the image sensor can form the imaging surface. The stop is disposed to adjust the amount of light incident to the lens. For example, the stop is disposed between the third lens and the fourth lens.

[0062] The optical imaging system is configured to satisfy at least one of the following conditional expressions:

[0063] Conditional Expression 1: 0.7 < TL / f < 1.0

[0064] Conditional Expression 2: F No. < 2.1

[0065] Condition Expression 3: D45 / TL < 0.18

[0066] Condition Expression 4: r1 / r4 < 0.1

[0067] Condition Expression 5: 1.2 < r2 / r3

[0068] Condition Expression 6: 5.0 < D56 / D12

[0069] Condition Expression 7: 1.6 < D45 / D34

[0070] Condition Expression 8: 0.1 < r1 / r11 < 0.3

[0071] In the condition expressions, TL is a distance from an object side surface of the first lens to an imaging plane, f is a total focal length of the optical imaging system, D12 is a distance from an image side surface of the first lens to an object side surface of the second lens, D34 is a distance from an image side surface of the third lens to an object side surface of the fourth lens, D45 is a distance from an image side surface of the fourth lens to an object side surface of the fifth lens, D56 is a distance from an image side surface of the fifth lens to an object side surface of the sixth lens, r1 is a radius of curvature of the object side surface of the first lens, r2 is a radius of curvature of the image side surface of the first lens, r3 is a radius of curvature of the object side surface of the second lens, r4 is a radius of curvature of the image side surface of the second lens, and r11 is a radius of curvature of the object side surface of the sixth lens.

[0072] Condition Expression 1 provides a condition for mounting the optical imaging system on a small terminal. An optical imaging system that does not satisfy Condition Expression 1 is difficult to mount on a small terminal and / or has difficulty in exhibiting a telephoto performance.

[0073] Condition Expression 3 provides a condition regarding a telephoto performance and a resolution. An optical system deviating from the numerical range of Condition Expression 3 has a poor telephoto performance and / or it is difficult to achieve a high resolution.

[0074] Condition Expression 4 provides a condition regarding a sensitivity and an aberration. An optical system deviating from the numerical range of Condition Expression 4 has a high sensitivity, making it difficult to correct an aberration.

[0075] An optical imaging system according to various examples will be described.

[0076] Reference will be made to Figure 1 An optical imaging system according to an example will be described.

[0077] The optical imaging system 100 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, and a sixth lens 160.

[0078] The first lens 110 has positive refractive power, its object side surface is convex, and its image side surface is concave. The second lens 120 has positive refractive power, its object side surface is convex, and its image side surface is concave. The third lens 130 has negative refractive power, its object side surface is concave, and its image side surface is concave. The third lens 130 has a shape in which an inflection point is formed on the object side surface and the image side surface. The fourth lens 140 has positive refractive power, its object side surface is convex, and its image side surface is convex. The fifth lens 150 has negative refractive power, its object side surface is convex, and its image side surface is concave. The fifth lens 150 has a shape in which an inflection point is formed on the object side surface and the image side surface. The sixth lens 160 has positive refractive power, its object side surface is convex, and its image side surface is concave. The sixth lens 160 has a shape in which an inflection point is formed on the object side surface and the image side surface.

[0079] The optical imaging system 100 includes a filter 170, an image sensor 180, and a stop ST. The filter 170 is disposed between the sixth lens 160 and the image sensor 180, and the stop ST is disposed between the third lens 130 and the fourth lens 140.

[0080] The optical imaging system 100 exhibits aberration characteristics as shown in FIG. 2. Figure 2 Table 1 and Table 2 represent lens characteristics and aspherical surface values of the optical imaging system 100.

[0081] Table 1

[0082]

[0083]

[0084] Table 2

[0085] Surface Number S1 S2 S3 S4 S5 S6 Radius of Curvature 1.7786 4.9836 3.1038 22.0293 -10.3019 3.4176 k -0.1592 5.8119 1.1896 -1.0000 -1.0000 1.2024 A -0.0072 -0.0287 -0.0157 -0.0149 0.0389 0.0167 B -0.0035 0.0837 0.0924 0.0446 0.0908 0.1451 C 0.0005 -0.0390 -0.0262 -0.0507 -0.1602 -0.3403 D 0.0037 0.0241 -0.0009 0.0236 0.1517 0.7485 E -0.0012 -0.0148 -0.0006 -0.0045 -0.0591 -0.9727 F -0.0003 0.0028 0.0000 0.0000 0.0035 0.7674 G 0.0000 0.0000 0.0000 0.0000 0.0034 -0.2158 H 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 J 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

[0086] Table 2 (continued)

[0087]

[0088]

[0089] An optical imaging system according to another example will be described with reference to Figure 3

[0090] The optical imaging system 200 includes a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, and a sixth lens 260.

[0091] ​The first lens 210 has positive refractive power, its object side surface is convex, and its image side surface is concave. The second lens 220 has positive refractive power, its object side surface is convex, and its image side surface is concave. The third lens 230 has negative refractive power, its object side surface is concave, and its image side surface is concave. The third lens 230 has a shape in which an inflection point is formed on the object side surface and the image side surface. The fourth lens 240 has positive refractive power, its object side surface is concave, and its image side surface is convex. The fifth lens 250 has negative refractive power, its object side surface is convex, and its image side surface is concave. The fifth lens 250 has a shape in which an inflection point is formed on the object side surface and the image side surface. The sixth lens 260 has positive refractive power, its object side surface is convex, and its image side surface is convex. The sixth lens 260 has a shape in which an inflection point is formed on the object side surface and the image side surface.

[0092] The optical imaging system 200 includes a filter 270, an image sensor 280, and a stop ST. The filter 270 is disposed between the sixth lens 260 and the image sensor 280, and the stop ST is disposed between the third lens 230 and the fourth lens 240.

[0093] The optical imaging system 200 exhibits aberration characteristics as shown in FIG. 6. Figure 4 Tables 3 and 4 represent lens characteristics and aspherical surface values of the optical imaging system 200.

[0094] Table 3

[0095]

[0096]

[0097] Table 4

[0098] Surface Number S1 S2 S3 S4 S5 S6 Radius of Curvature 1.6895 4.4223 3.2222 265.4716 -7.3340 3.4564 k -0.0096 6.8208 1.6967 -1.0000 -1.0000 4.5330 A -0.0120 -0.0703 -0.0587 -0.0230 0.0370 0.0330 B -0.0028 0.1647 0.1710 0.0367 0.1078 0.0988 C -0.0056 -0.1039 -0.0867 -0.0304 -0.1449 0.0315 D 0.0108 0.0558 0.0212 0.0110 0.0991 -0.2377 E -0.0055 -0.0262 -0.0038 -0.0021 -0.0183 0.3026 F 0.0006 0.0049 0.0000 0.0000 0.0000 0.0000 G 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 H 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 J 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

[0099] Table 4 (continued)

[0100]

[0101]

[0102] An optical imaging system according to another example will be described with reference to Figure 5

[0103] The optical imaging system 300 includes a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, and a sixth lens 360.

[0104] ​The first lens 310 has positive refractive power, its object side surface is convex, and its image side surface is concave. The second lens 320 has positive refractive power, its object side surface is convex, and its image side surface is concave. The third lens 330 has negative refractive power, its object side surface is concave, and its image side surface is concave. The third lens 330 has a shape in which an inflection point is formed on the object side surface and the image side surface. The fourth lens 340 has positive refractive power, its object side surface is concave, and its image side surface is convex. The fifth lens 350 has negative refractive power, its object side surface is convex, and its image side surface is concave. The fifth lens 350 has a shape in which an inflection point is formed on the object side surface and the image side surface. The sixth lens 360 has positive refractive power, its object side surface is convex, and its image side surface is convex. The sixth lens 360 has a shape in which an inflection point is formed on the object side surface and the image side surface.

[0105] The optical imaging system 300 includes a filter 370, an image sensor 380, and a stop ST. The filter 370 is disposed between the sixth lens 360 and the image sensor 380, and the stop ST is disposed between the third lens 330 and the fourth lens 340.

[0106] The optical imaging system 300 exhibits aberration characteristics as shown in Table 1. Figure 6 Table 5 and Table 6 represent lens characteristics and aspherical surface values of the optical imaging system 300.

[0107] Table 5

[0108]

[0109]

[0110] Table 6

[0111]

[0112]

[0113] Table 6 (continued)

[0114]

[0115] Table 7 represents conditional expression values of the optical imaging system according to the above-described examples.

[0116] Table 7

[0117]

[0118]

[0119] The lenses of the optical imaging system described above have a focal length within a predetermined (certain) range. For example, the focal length of the first lens is within a range of 4.0 to 5.4, the focal length of the second lens is within a range of 5.0 to 8.0, the focal length of the third lens is within a range of -5.0 to -3.0, the focal length of the fourth lens is within a range higher than 30, the focal length of the fifth lens is within a range of -6.0 to -3.5, and the focal length of the sixth lens is within a range of 8.0 to 15.

[0120] The optical imaging system according to the various examples described herein can be mounted on a small terminal while being capable of implementing long distance image capturing.

[0121] The optical imaging system according to the various examples described herein provides an optical imaging system having a low F No. that can be mounted on a small terminal while being capable of capturing long distance images.

[0122] While the present disclosure includes specific examples, it will be apparent to those skilled in the art, after understanding the disclosure provided herein, that various changes in form and details can be made without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each example can be considered as being applicable to some other examples. Suitable results can be obtained if the described techniques are performed in a different order, and / or if the described systems, architectures, devices or circuits are combined or substituted with other systems, architectures, devices or circuits or their equivalents. Thus, the scope of the present disclosure should not be limited by the specific examples described herein, but only by the claims and their equivalents. All variations and modifications of the systems, architectures, devices or circuits described herein that serve the same purposes are intended to be within the scope of the present disclosure.

Claims

1. An optical imaging system, comprising: The first lens has positive refractive power; The second lens has positive refractive power; The third lens has negative refractive power; The fourth lens has positive refractive power; The fifth lens has negative refractive power; and The sixth lens has positive refractive power. The first lens to the sixth lens are arranged sequentially from the object side toward the imaging plane. The optical imaging system comprises six lenses with refractive power. The first lens has a focal length in the range of 4.0 mm to 5.4 mm, and the second lens has a focal length in the range of 5.0 mm to 8.0 mm. Where 0.7 < TL / f < 1.0, TL is the distance from the object surface of the first lens to the imaging plane, and f is the total focal length of the optical imaging system. Wherein, D45 / TL < 0.18, and D45 is the distance from the image surface of the fourth lens to the object surface of the fifth lens.

2. The optical imaging system according to claim 1, wherein, The first lens has a convex object surface.

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

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

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

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

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

8. The optical imaging system according to claim 1, wherein, The sixth lens has a convex image-side surface.

9. An optical imaging system, comprising: The first lens has positive refractive power; The second lens has positive refractive power; The third lens has negative refractive power; The fourth lens has positive refractive power; The fifth lens has negative refractive power; and The sixth lens has positive refractive power. The first lens to the sixth lens are arranged sequentially from the object side toward the imaging plane. The optical imaging system comprises six lenses with refractive power. The first lens has a focal length in the range of 4.0mm to 5.4mm, and the sixth lens has a focal length in the range of 8.0mm to 15.0mm. Where 0.7 < TL / f < 1.0, TL is the distance from the object surface of the first lens to the imaging plane, and f is the total focal length of the optical imaging system. Wherein, D45 / TL < 0.18, and D45 is the distance from the image surface of the fourth lens to the object surface of the fifth lens.

10. The optical imaging system according to claim 9, wherein, The fourth lens has a convex image-side surface.

11. The optical imaging system according to claim 9, wherein, The fifth lens has a convex object surface.

12. The optical imaging system according to claim 9, wherein, The sixth lens has a convex object surface.

13. The optical imaging system according to claim 9, wherein, 1.7700 ≤ F No. < 2.1, where F No. is the F number of the optical imaging system.

14. The optical imaging system according to claim 9, wherein, 0.0064 ≤ r1 / r4 < 0.1, where r1 is the radius of curvature of the object surface of the first lens and r4 is the radius of curvature of the image surface of the second lens.

15. The optical imaging system according to claim 9, wherein, 1.2 < r2 / r3 ≤ 1.7996, where r2 is the radius of curvature of the image-side surface of the first lens and r3 is the radius of curvature of the object-side surface of the second lens.

16. The optical imaging system according to claim 9, wherein, 0.1 < r1 / r11 < 0.3, where r1 is the radius of curvature of the object surface of the first lens, and r11 is the radius of curvature of the object surface of the sixth lens.

17. The optical imaging system according to claim 9, wherein, 5.0 < D56 / D12 ≤ 7.6700, where D12 is the distance from the image surface of the first lens to the object surface of the second lens, and D56 is the distance from the image surface of the fifth lens to the object surface of the sixth lens.

18. The optical imaging system according to claim 9, wherein, 1.6 < D45 / D34 ≤ 2.6970, where D34 is the distance from the image surface of the third lens to the object surface of the fourth lens.

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