Optical image capturing system
By designing an optical imaging system with a combination of multiple positive refractive lenses, the problem of difficulty in imaging in a low-illumination environment is solved, and high-efficiency, low-illumination imaging and miniaturization are achieved.
Patent Information
- Application Number
- CN202510365958.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2018-11-19
- Filing Date
- 2019-10-10
- Publication Date
- 2025-05-06
AI Technical Summary
The camera optical system on small terminals is difficult to achieve high resolution imaging in low-illumination environments, and its short overall length leads to a large number of F, making it difficult to meet the needs of low-illumination imaging.
An optical imaging system consisting of a plurality of lenses with positive refractive power is designed, and the combination and structure of the lenses are optimized to meet specific focal length, radius of curvature and refractive index conditions to ensure effective imaging in a low illumination environment.
It realizes high-efficiency imaging in a low-illumination environment, while maintaining the miniaturization characteristics of the optical imaging system, meeting the requirements of FNo. equal to or less than 1.0.
Smart Images
Figure CN119937127A_ABST
Abstract
Description
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2018-0142402 filed in the Korean Intellectual Property Office on November 19, 2018, the disclosure of which is incorporated herein by reference in its entirety for all purposes. Technical Field
[0003] The following description relates to an optical imaging system capable of achieving a bright image. Background Art
[0004] The optical system for the camera installed in the small terminal has a short total length, and thus it may be difficult to achieve a low F number. In this regard, the camera for the small terminal may not be able to obtain a high-resolution image capture of an object and may not be able to image the object in a low-light environment. Summary of the invention
[0005] The purpose of providing this summary is to introduce a selection of inventive concepts in a concise form, and these inventive concepts will be further described in the following detailed description. This summary is not intended to identify the key features or essential features of the subject matter claimed, nor is it intended to help determine the scope of the subject matter claimed.
[0006] The present application relates to an optical imaging system capable of imaging an object in a low-light environment while being mounted on a small terminal.
[0007] In a general aspect, an optical imaging system includes a first lens having positive refractive power, a second lens having positive refractive power, a third lens having positive refractive power, and a fourth lens having positive refractive power, and an FNo. of the optical imaging system is equal to or less than 1.0.
[0008] The visible light transmittance of the first lens may be equal to or less than 5%.
[0009] The second lens may include an inflection point on the image side surface
[0010] The third lens may include a convex image-side surface.
[0011] The fourth lens may include a concave image-side surface.
[0012] The optical imaging system may satisfy 5.0<(f1+f2) / f<80, where f is the focal length of the optical imaging system, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.
[0013] The optical imaging system can satisfy 1.0 < f3 / f < 2.5, where f is the focal length of the optical imaging system, and f3 is the focal length of the third lens.
[0014] The optical imaging system can satisfy 1.0 < f4 / f < 6.0, where f is the focal length of the optical imaging system, and f4 is the focal length of the fourth lens.
[0015] The optical imaging system can satisfy 0.3 < R1 / f < 2.0, where f is the focal length of the optical imaging system, and R1 is the radius of curvature of the object side surface of the first lens.
[0016] The optical imaging system can satisfy 0.3 < R3 / f < 2.0, where f is the focal length of the optical imaging system, and R3 is the radius of curvature of the object side surface of the second lens.
[0017] The optical imaging system can satisfy 5.0 < R5 / f < 80, where f is the focal length of the optical imaging system, and R5 is the radius of curvature of the object side surface of the third lens.
[0018] The optical imaging system can satisfy 1.580 < Nd1 < 1.640, where Nd1 is the refractive index of the first lens.
[0019] In another general aspect, the optical imaging system includes a plurality of lenses sequentially arranged from the object side to the imaging surface of the optical imaging system, and each lens in the plurality of lenses has a refractive power. Among the plurality of lenses, the lens closest to the object side has a positive refractive power, and the F No. of the optical imaging system is equal to or less than 1.0.
[0020] The optical imaging system can satisfy 1.0 < TTL / f < 2.0, where TTL is the distance from the object side surface of the lens closest to the object side to the imaging surface, and f is the focal length of the optical imaging system.
[0021] The optical imaging system can satisfy 0.3 < R1 / TTL < 5.0, where TTL is the distance from the object side surface of the lens closest to the object side to the imaging surface, and R1 is the radius of curvature of the object side surface of the lens closest to the object side.
[0022] The optical imaging system can satisfy 0.5 < EPD / TTL < 0.7, where TTL is the distance from the object side surface of the lens closest to the object side to the imaging surface, and EPD is the entrance pupil diameter.
[0023] Other features and aspects will become apparent from the following detailed description, the drawings, and the appended claims. Description of the Drawings
[0024] Figure 1 is a view showing an optical imaging system according to the first example.
[0025] Figure 2 yes Figure 1 Aberration curves of the optical imaging system shown in .
[0026] Figure 3 is a view showing an optical imaging system according to a second example.
[0027] Figure 4 yes Figure 3 Aberration curves of the optical imaging system shown in .
[0028] Figure 5 is a view showing an optical imaging system according to a third example.
[0029] Figure 6 yes Figure 5 Aberration curves of the optical imaging system shown in .
[0030] Figure 7 is a view showing an optical imaging system according to a fourth example.
[0031] Figure 8 yes Figure 7 Aberration curves of the optical imaging system shown in .
[0032] Fig. 9 is a view showing an optical imaging system according to a fifth example.
[0033] Fig.10 yes Fig. 9 Aberration curves of the optical imaging system shown in .
[0034] Throughout the drawings and detailed description, 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 sizes, proportions, and depictions of elements in the drawings may be exaggerated. DETAILED DESCRIPTION
[0035] The following detailed description is provided to help the reader obtain a comprehensive understanding of the method, device and / or system described in this application. However, after understanding the disclosure of this application, various changes, modifications and equivalences of the method, device and / or system described in this application will be apparent. For example, the order of operations described in this application is merely an example, and except for the operations that must occur in a specific order, it is not limited to the order set forth in this application, and obvious changes can be made after understanding the disclosure of this application. In addition, for greater clarity and brevity, the description of features well known in the art may be omitted.
[0036] The features described in this application can be implemented in different forms and should not be understood as being limited to the examples described in this application. Rather, the examples described in this application are provided only to illustrate some of the many possible ways to implement the methods, devices and / or systems described in this application, which will be apparent after understanding the disclosure of this application.
[0037] It should be noted that in this application, the use of the word "may" with respect to examples or embodiments, such as with respect to what an example or embodiment may include or implement, means that there is at least one example or embodiment that includes or implements such features, and all examples and embodiments are not limited thereto.
[0038] Throughout the specification, when an element such as a layer, a region, or a substrate is described as being “on,” “connected to,” or “coupled to” another element, the element may be directly “on,” “connected to,” or “coupled to” the other element, or one or more other elements may be present between the element and the other element. Conversely, when an element is described as being “directly on,” “directly connected to,” or “directly coupled to” another element, there may be no other elements between the element and the other element.
[0039] As used in this application, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.
[0040] Although the terms "first", "second" and "third" may be used in this application to describe various components, parts, regions, layers or parts, these components, parts, regions, layers or parts are not limited by these terms. More specifically, these terms are only used to distinguish one component, part, region, layer or part from another component, part, region, layer or part. Therefore, without departing from the teachings of the examples described in this application, the first component, first component, first region, first layer or first part mentioned in the example may also be referred to as the second component, second component, second region, second layer or second part.
[0041] Spatially relative terms such as "above", "upper", "under", and "lower" may be used in this application for descriptive convenience to describe the relationship of one element relative to another element as shown in the accompanying drawings. In addition to covering the orientations depicted in the accompanying drawings, these spatially relative terms are intended to also cover different orientations of the device in use or operation. For example, if the device in the accompanying drawings is flipped, an element described as being "above" or "upper" relative to another element will be "under" or "under" relative to the other element. Therefore, depending on the spatial orientation of the device, the term "above" covers both "above" and "under" orientations. The device may also be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially relative terms used in this application should be interpreted accordingly.
[0042] The terms used in this application are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the articles "a", "an" and "the" are intended to also include plural forms. The words "include", "comprise" and "have" indicate the presence of the 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.
[0043] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Therefore, the examples described in the present application are not limited to the specific shapes shown in the drawings, but include variations in shapes that occur during manufacturing.
[0044] The features of the examples described in this application can be combined in various ways that will be apparent after understanding the disclosure of this application. In addition, although the examples described in this application have multiple configurations, other configurations that will be apparent after understanding the disclosure of this application are also possible.
[0045] For illustrative purposes, the thickness, size, and shape of the lens shown in the drawings may be exaggerated. In addition, the shape of the spherical or aspherical surface of the lens described and shown in the detailed description or drawings is only an example and is not limited to the shape of the lens.
[0046] In this specification, all numerical values of the radius of curvature and thickness of a lens, distance, focal length, etc. are expressed in millimeters (mm), and angles are expressed in degrees.
[0047] In this specification, the description of the shape of a lens refers to the shape of the paraxial region of the lens. For example, the meaning of the object side surface of the first lens being convex is that the paraxial region of the object side surface of the first lens is convex. Therefore, even when the object side surface of the lens is described as convex, the entire object side surface of the lens may not be convex. For example, even when the image side surface of the first lens is described as concave, the edge of the image side surface of the first lens may be convex. For reference, the paraxial region described above refers to the region including the optical axis.
[0048] The optical imaging system according to the example may include a plurality of lenses arranged along the optical axis. For example, the optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens arranged in sequence along the optical axis. Here, the first lens refers to the lens closest to the object (or subject), and the fourth lens refers to the lens closest to the imaging surface or the image sensor.
[0049] Next, the configuration of the optical imaging system will be described.
[0050] The optical imaging system includes a plurality of lenses. The optical imaging system includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence from the object side as described above.
[0051] The optical imaging system may further include an image sensor and a filter. The image sensor forms an imaging surface and converts light refracted by the first lens to the fourth lens into an electrical signal. The filter is disposed between the lens and the imaging surface and blocks the intrusion of foreign matter. The filter may be an infrared pass filter that allows infrared rays to pass. In addition, the filter may be configured to significantly reduce the transmittance of visible light.
[0052] The optical imaging system may further include an aperture and a spacer. The aperture is disposed in front of the first lens or between the lens and the adjacent lens to adjust the amount of light incident on the imaging surface. The spacer is disposed between the lenses to allow the distance between the lenses to be constant. In addition, the spacer is made of a light-shielding material and can block unnecessary light from penetrating to the rib side of the lens.
[0053] Next, lenses forming the optical imaging system will be described.
[0054] The first lens has a refractive power. For example, the first lens may have a positive refractive power. One surface of the first lens is convex. For example, the object side surface of the first lens may be convex. The first lens includes an aspherical surface. For example, two surfaces of the first lens may be aspherical surfaces. The first lens is configured to reduce the transmittance of visible light. For example, the visible light transmittance of the first lens may be equal to or less than 5%. The first lens may be manufactured to be substantially dark in color. For example, the first lens may be manufactured using a black-based raw material, thereby reducing the visible light transmittance and increasing the infrared transmittance. The first lens has a relatively high refractive index. For example, the refractive index of the first lens may be greater than the refractive index of each of the second lens to the fourth lens.
[0055] The second lens has a refractive power. For example, the second lens may have a positive refractive power. One surface of the second lens is convex. For example, the object side surface of the second lens may be convex. The second lens may have an aspheric surface. For example, both surfaces of the second lens may be aspheric surfaces. In some embodiments, the second lens may include an inflection point on its image side surface.
[0056] The third lens has a refractive power. For example, the third lens may have a positive refractive power. At least one surface of the third lens is convex. For example, the object side surface or the image side surface of the third lens may be convex, or both surfaces of the third lens may be convex. The third lens includes an aspherical surface. For example, both surfaces of the third lens may be aspherical surfaces.
[0057] The fourth lens has a refractive power. For example, the fourth lens may have a positive refractive power. One surface of the fourth lens is concave. For example, the image side surface of the fourth lens may be concave. The fourth lens has a shape including an inflection point. For example, an inflection point may be formed in at least one of the object side surface and the image side surface of the fourth lens. Therefore, in at least one surface of the fourth lens, the shape of the paraxial region may be different from the shape of the peripheral portion. For example, in the fourth lens, the paraxial region is concave and the edge portion of the paraxial region may be convex. The fourth lens includes an aspherical surface. For example, two surfaces of the fourth lens may be aspherical surfaces.
[0058] The aspherical surfaces of the first to fourth lenses may be expressed by the following Equation 1:
[0059] Equation 1
[0060]
[0061] In Equation 1, c is the inverse of the radius of curvature of the lens, K is the cone constant, Y is the distance from a certain point on the aspherical surface of the lens to the optical axis in a direction perpendicular to the optical axis, and A to H are aspherical constants. In addition, Z (or SAG) is the distance in the optical axis direction between a certain point on the aspherical surface of the lens at a distance Y from the optical axis and a tangent plane intersecting the vertex of the aspherical surface of the lens.
[0062] The optical imaging system may satisfy one or more of the following conditional expressions:
[0063] Conditional Expression 1 1.0 <TTL / f<2.0
[0064] Conditional expression 2 0.3 <R1 / TTL<5.0
[0065] Conditional expression 3 0.5 <EPD / TTL<0.7
[0066] Conditional expression 4 5.0<(f1+f2) / f<80
[0067] Conditional Expression 5 1.0 <f3 / f<2.5
[0068] Conditional Expressions 6 1.0 <f4 / f<6.0
[0069] Conditional expression 7 0.3 <R1 / f<2.0
[0070] Conditional expression 8 0.3 <R3 / f<2.0
[0071] Conditional Expressions 9 5.0 <R5 / f<80
[0072] Conditional expression 10 0.8 <F No.<1.5
[0073] Conditional expression 11 1.580 <Nd1<1.640。
[0074] In the conditional expression, TTL is the distance from the object side surface of the first lens to the imaging surface, 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, f4 is the focal length of the fourth lens, R1 is the radius of curvature of the object side surface of the first lens, R3 is the radius of curvature of the object side surface of the second lens, R5 is the radius of curvature of the object side surface of the third lens, EPD is the entrance pupil diameter, and Nd1 is the refractive index of the first lens.
[0075] Next, various examples of the optical imaging system will be described.
[0076] Figure 1 is a view showing an optical imaging system according to a first example of an embodiment, and Figure 2 yes Figure 1 Aberration curves of the optical imaging system.
[0077] The optical imaging system 100 includes a first lens 110 , a second lens 120 , a third lens 130 , and a fourth lens 140 .
[0078] The first lens 110 has positive refractive power, and the object side surface is convex and the image side surface is concave. The second lens 120 has positive refractive power, and the object side surface is convex and the image side surface is concave. The third lens 130 has positive refractive power, and the object side surface is convex and the image side surface is convex. The fourth lens 140 has positive refractive power, and the object side surface is convex and the image side surface is concave. In addition, an inflection point is formed on the object side surface and the image side surface of the fourth lens 140.
[0079] The optical imaging system 100 further includes a stop ST, a filter 150, and an image sensor 160. The stop ST is disposed in front of the first lens 110, and adjusts the amount of light incident on the image sensor 160. The filter 150 is disposed between the fourth lens 140 and the image sensor 160. The image sensor 160 forms an imaging surface on which an image of a subject can be focused.
[0080] Table 1 shows physical properties of lenses constituting the optical imaging system 100 , and Table 2 shows aspherical coefficients of lenses constituting the optical imaging system 100 .
[0081] Table 1
[0082]
[0083] Table 2
[0084]
[0085]
[0086] Figure 3 is a view showing an optical imaging system according to a second example of an embodiment, and Figure 4 yes Figure 3 Aberration curves of the optical imaging system.
[0087] The optical imaging system 200 includes a first lens 210 , a second lens 220 , a third lens 230 , and a fourth lens 240 .
[0088] The first lens 210 has positive refractive power, and the object side surface is convex and the image side surface is concave. The second lens 220 has positive refractive power, and the object side surface is convex and the image side surface is concave. The third lens 230 has positive refractive power, and the object side surface is convex and the image side surface is convex. The fourth lens 240 has positive refractive power, and the object side surface is convex and the image side surface is concave. In addition, an inflection point is formed on the object side surface and the image side surface of the fourth lens 240.
[0089] The optical imaging system 200 further includes a stop ST, a filter 250, and an image sensor 260. The stop ST is disposed in front of the first lens 210, and adjusts the amount of light incident on the image sensor 260. The filter 250 is disposed between the fourth lens 240 and the image sensor 260. The image sensor 260 forms an imaging surface on which an image of a subject can be focused.
[0090] Table 3 shows physical properties of lenses constituting the optical imaging system 200 , and Table 4 shows aspherical coefficients of lenses constituting the optical imaging system 200 .
[0091] Table 3
[0092]
[0093] Table 4
[0094]
[0095]
[0096] Figure 5 is a view showing an optical imaging system according to a third example of an embodiment, and Figure 6 yes Figure 5 Aberration curves of the optical imaging system.
[0097] The optical imaging system 300 includes a first lens 310 , a second lens 320 , a third lens 330 , and a fourth lens 340 .
[0098] The first lens 310 has positive refractive power, and the object side surface is convex and the image side surface is concave. The second lens 320 has positive refractive power, and the object side surface is convex and the image side surface is concave. The third lens 330 has positive refractive power, and the object side surface is convex and the image side surface is convex. The fourth lens 340 has positive refractive power, and the object side surface is convex and the image side surface is concave. In addition, an inflection point is formed on the object side surface and the image side surface of the fourth lens 340.
[0099] The optical imaging system 300 further includes a stop ST, a filter 350, and an image sensor 360. The stop ST is disposed in front of the first lens 310, and adjusts the amount of light incident on the image sensor 360. The filter 350 is disposed between the fourth lens 340 and the image sensor 360. The image sensor 360 forms an imaging surface on which an image of a subject can be focused.
[0100] Table 5 shows physical properties of lenses constituting the optical imaging system 300 , and Table 6 shows aspherical coefficients of lenses constituting the optical imaging system 300 .
[0101] Table 5
[0102]
[0103] Table 6
[0104]
[0105]
[0106] Figure 7 is a view showing an optical imaging system according to a fourth example of an embodiment, and Figure 8 yes Figure 7 Aberration curves of the optical imaging system.
[0107] The optical imaging system 400 includes a first lens 410 , a second lens 420 , a third lens 430 , and a fourth lens 440 .
[0108] The first lens 410 has positive refractive power, and the object side surface is convex and the image side surface is concave. The second lens 420 has positive refractive power, and the object side surface is convex and the image side surface is concave. The third lens 430 has positive refractive power, and the object side surface is convex and the image side surface is convex. The fourth lens 440 has positive refractive power, and the object side surface is convex and the image side surface is concave. In addition, an inflection point is formed on the object side surface and the image side surface of the fourth lens 440.
[0109] The optical imaging system 400 further includes a stop ST, a filter 450, and an image sensor 460. The stop ST is disposed in front of the first lens 410, and adjusts the amount of light incident on the image sensor 460. The filter 450 is disposed between the fourth lens 440 and the image sensor 460. The image sensor 460 forms an imaging surface on which an image of a subject can be focused.
[0110] Table 7 shows physical properties of lenses constituting the optical imaging system 400 , and Table 8 shows aspherical coefficients of lenses constituting the optical imaging system 400 .
[0111] Table 7
[0112]
[0113] Table 8
[0114] Face number S1 S2 S3 S4 S5 S6 S7 S8 K -0.63110 -7.37100 -1.95300 0.13240 92.09000 -99.00000 -0.68650 -0.69820 A -0.03269 -0.03513 -0.05978 -0.00349 0.14740 -0.13870 -0.12450 0.01949 B 0.04752 0.01375 -0.12680 -0.18340 -0.16240 0.04687 -0.00301 -0.11130 C -0.05507 0.01136 0.10450 0.08624 0.13250 0.11680 -0.00373 0.05649 D 0.04047 -0.01110 -0.03937 -0.00633 -0.07049 -0.14400 0.00200 -0.01576 E -0.01777 0.00216 0.00938 -0.00906 0.02075 0.07326 -0.00022 0.00252 F 0.00399 0.00001 -0.00145 0.00347 -0.00251 -0.01783 -1.2E-06 -0.00021 G -0.00038 0.00000 0.00014 -0.00045 -0.00002 0.00169 -5.7E-08 0.00001 H 0 0 0 0 0 0 0 0
[0115] Fig. 9 is a view showing an optical imaging system according to a fifth example of an embodiment, and Fig.10 yes Fig. 9 Aberration curves of the optical imaging system.
[0116] The optical imaging system 500 includes a first lens 510 , a second lens 520 , a third lens 530 , and a fourth lens 540 .
[0117] The first lens 510 has positive refractive power, and the object side surface is convex and the image side surface is concave. The second lens 520 has positive refractive power, and the object side surface is convex and the image side surface is concave. The third lens 530 has positive refractive power, and the object side surface is convex and the image side surface is convex. The fourth lens 540 has positive refractive power, and the object side surface is convex and the image side surface is concave. In addition, an inflection point is formed on the object side surface and the image side surface of the fourth lens 540.
[0118] The optical imaging system 500 further includes a stop ST, a filter 550, and an image sensor 560. The stop ST is disposed in front of the first lens 510, and adjusts the amount of light incident on the image sensor 560. The filter 550 is disposed between the fourth lens 540 and the image sensor 560. The image sensor 560 forms an imaging surface on which an image of a subject can be focused.
[0119] Table 9 shows physical properties of the lenses constituting the optical imaging system 500 , and Table 10 shows aspherical coefficients of the lenses constituting the optical imaging system 500 .
[0120] Table 9
[0121]
[0122]
[0123] Table 10
[0124] Face number S1 S2 S3 S4 S5 S6 S7 S8 K -0.64240 -5.62200 -2.10700 -0.10510 92.09000 -99.00000 -0.61060 -0.46600 A -0.03129 -0.03600 -0.05234 -0.00064 0.16820 -0.12020 -0.09522 0.04899 B 0.05392 0.02173 -0.12650 -0.18290 -0.17900 0.04382 -0.01529 -0.12440 C -0.05860 0.01280 0.10540 0.08824 0.13550 0.11290 -0.00327 0.05591 D 0.04136 -0.01129 -0.03825 -0.00656 -0.07045 -0.14300 0.00237 -0.01479 E -0.01738 0.00200 0.00960 -0.00917 0.02075 0.07327 -0.00030 0.00236 F 0.00384 -0.00009 -0.00171 0.00368 -0.00251 -0.01783 -1.1E-06 -0.00021 G -0.00038 0.00000 0.00014 -0.00045 -0.00002 0.00169 -9.6E-15 0.00001 H 0 0 0 0 0 0 0 0
[0125] Table 11 shows main optical characteristic values of the optical imaging systems according to the first to fifth examples, and Table 12 shows conditional expression values of the optical imaging systems according to the first to fifth examples.
[0126] Table 11
[0127] Optical properties First example Second example Third Example Fourth Example Fifth example EPD 3.0135 3.0135 3.0800 3.1738 3.2163 TTL 4.650 4.650 4.650 4.650 4.650 f 2.900 2.940 2.950 3.020 3.020 f1 129.211 101.544 90.740 33.573 25.335 f2 7.550 7.565 7.545 9.111 9.844 f3 4.859 5.065 5.382 6.243 6.328 f4 13.848 13.618 12.242 8.783 8.102
[0128] Table 12
[0129]
[0130]
[0131] The optical imaging system according to the example may generally have the following optical characteristics. For example, the total length TTL of the optical imaging system may be in the range of 4.0 mm to 5.2 mm, the focal length f may be in the range of 2.6 mm to 3.4 mm, and the entrance pupil diameter EPD may be in the range of 2.80 mm to 3.4 mm. The focal length f1 of the first lens may be in the range of 20 mm to 140 mm, the focal length f2 of the second lens may be in the range of 5.0 mm to 12 mm, the focal length f3 of the third lens may be in the range of 3.0 mm to 8.0 mm, and the focal length f4 of the fourth lens may be in the range of 6.0 mm to 16.0 mm.
[0132] In the optical imaging system according to the example, the distance between the second lens and the third lens can be the largest. In addition, the distance D23 from the image side surface of the second lens to the object side surface of the third lens can be greater than the distance D12 from the image side surface of the first lens to the object side surface of the second lens and the distance D34 from the image side surface of the third lens to the object side surface of the fourth lens.
[0133] In the optical imaging system according to the example, the distance between the third lens and the fourth lens can be the smallest. In addition, the distance D34 from the image side surface of the third lens to the object side surface of the fourth lens can be smaller than the distance D12 from the image side surface of the first lens to the object side surface of the second lens and the distance D23 from the image side surface of the second lens to the object side surface of the third lens.
[0134] In the optical imaging system according to the example, the first lens may be the thickest lens. In addition, the thickness TD1 of the first lens at the center of the optical axis is greater than the thickness TD2 of the second lens at the center of the optical axis, the thickness TD3 of the third lens at the center of the optical axis, and the thickness TD4 of the fourth lens at the center of the optical axis.
[0135] In the optical imaging system according to the example, the second lens or the fourth lens may be a lens thinner than an adjacent lens. In addition, the thickness TD2 of the second lens at the center of the optical axis is smaller than the thickness TD1 of the first lens at the center of the optical axis and the thickness TD3 of the third lens at the center of the optical axis. In addition, the thickness TD4 of the fourth lens at the center of the optical axis is smaller than the thickness TD3 of the third lens at the center of the optical axis.
[0136] As described above, according to the examples, an optical imaging system capable of capturing an image under low illumination while achieving miniaturization can be realized.
[0137] Although the present disclosure includes specific examples, it will be apparent after understanding the disclosure of the present 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 in this application should be considered only in a descriptive sense and not for limiting purposes. The description of the features or aspects in each example should be considered to be applicable to similar features or aspects in other examples. Suitable results can also be obtained if the described techniques are performed in a different order, and / or if the components in the described systems, architectures, devices or circuits are combined in different ways and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of the present disclosure should not be limited by this detailed description, 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 the present disclosure.
Claims
1. An optical imaging system, comprising: A first lens having a positive refractive power; A second lens having a positive refractive power; A third lens having a positive refractive power; And A fourth lens having a positive refractive power, wherein the first lens to the fourth lens are sequentially arranged from the object side towards the imaging surface, wherein the number of lenses having refractive power in the optical imaging system is four, wherein 5.0 < R5 / f < 80, where f is the focal length of the optical imaging system and R5 is the radius of curvature of the object side surface of the third lens, and wherein the optical imaging system has a total length TTL in the range of 2.60 mm to 3.4 mm, where TTL is the distance from the object side surface of the first lens to the imaging surface.
2. The optical imaging system of claim 1, wherein: The first lens has a convex object side surface.
3. The optical imaging system of claim 1, wherein: The second lens has a convex object side surface.
4. The optical imaging system of claim 1, wherein: The third lens has a convex object side surface.
5. The optical imaging system of claim 1, wherein: The fourth lens has a convex object side surface.
6. An optical imaging system, comprising: A first lens having a positive refractive power; A second lens having a positive refractive power; A third lens having a positive refractive power; And A fourth lens having a positive refractive power, wherein the first lens to the fourth lens are sequentially arranged from the object side towards the imaging surface, wherein the number of lenses having refractive power in the optical imaging system is four, wherein the first lens has a focal length in the range of 20 mm to 140 mm, and wherein the optical imaging system has a total length TTL in the range of 2.60 mm to 3.4 mm, where TTL is the distance from the object side surface of the first lens to the imaging surface.
7. The optical imaging system of claim 6, wherein: The first lens has a convex object side surface.
8. The optical imaging system of claim 6, wherein: The second lens has a convex object side surface.
9. The optical imaging system of claim 6, wherein: The third lens has a convex object side surface.
10. The optical imaging system of claim 6, wherein: The fourth lens has a convex object side surface.