Optical imaging system

Abstract

An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens, wherein: the first lens has a refractive power; the second lens includes a first reflective region formed on an object side surface of the second lens; the third lens has a second reflective region formed on an image side surface of the third lens; and the fourth lens has a refractive power.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2018-0089913, filed with the Korean Intellectual Property Office on August 1, 2018, and Korean Patent Application No. 10-2018-0115989, filed with the Korean Intellectual Property Office on September 28, 2018, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] This application relates to an optical imaging system capable of imaging objects at a distance. Background Technology

[0004] Small-sized optical imaging systems installed in portable terminal devices are typically optimized for imaging objects at close range. Therefore, such small-sized optical imaging systems may struggle to image objects at long distances. While small-sized optical imaging systems exist optimized for imaging objects at long distances, the limited installation space in portable terminal devices may make it difficult to increase the focal length ratio by two times or more.

[0005] The above information is presented as background information only to aid in understanding this disclosure. No determination or assertion has been made regarding whether any of the above content is applicable to the prior art of this disclosure. Summary of the Invention

[0006] 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.

[0007] In one general aspect, the optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens, wherein: the first lens has refractive power; the second lens has a first reflective region formed on the object-side surface of the second lens; the third lens includes a second reflective region formed on the image-side surface of the third lens; and the fourth lens has refractive power.

[0008] The first reflection region can be configured to include the optical axis of the second lens.

[0009] The second reflection region can be formed on the area outside the optical axis of the third lens.

[0010] The second reflective region may surround the optical axis and be spaced apart from the optical axis by a refractive region formed on the image side of the third lens, and the refractive region may include the optical axis of the third lens.

[0011] The first lens may include a convex object side surface.

[0012] The second lens may include a convex image side surface.

[0013] The third lens may include a concave object side surface.

[0014] The third lens may include a convex image side surface.

[0015] The fourth lens may include a convex image side surface.

[0016] The second lens may have an effective diameter smaller than the effective diameters of the first lens and the third lens.

[0017] In another general aspect, an optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially arranged from the object side, wherein one or more of the first lens to the fourth lens includes a reflection region that reflects light refracted from an adjacent lens along the light propagation path, and wherein the optical imaging system satisfies the conditional expression:

[0018] 1.1 ≤ f / TL2, where f is the focal length of the optical imaging system and TL2 is the total optical length of the optical imaging system.

[0019] The second lens may have a reflection region formed on the object side surface of the second lens.

[0020] The third lens may have a reflection region formed on the image side surface of the third lens.

[0021] The first lens may include a convex object side surface.

[0022] The optical imaging system may satisfy the conditional expression: TL2 / TL1 < 2.1, where TL1 is the total lens length of the optical imaging system and TL2 is the total optical length of the optical imaging system.

[0023] The optical imaging system may satisfy one or more of the following conditional expressions: 0.1 < L1S1 / f < 0.95, -0.95 < L2S1 / f < -0.1, -1.5 < L3S1 / f < -0.2, -1.55 < L3S2 / f < -0.25, where L1S1 is the radius of curvature of the object side surface of the first lens, L2S1 is the radius of curvature of the object side surface of the second lens, L3S1 is the radius of curvature of the object side surface of the third lens, and L3S2 is the radius of curvature of the image side surface of the third lens.

[0024] In another general aspect, the optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side, wherein incident light from the object side is refracted by the first lens, reflected by the reflective region of the third lens, reflected by the reflective region of the second lens, refracted by the refractive region of the third lens, and refracted by the fourth lens in this order to form an image.

[0025] The reflection area of ​​the third lens can be set on the image side of the third lens and spaced apart from the optical axis of the third lens.

[0026] The refractive region of the third lens may include the optical axis on the image-side surface of the third lens.

[0027] The reflection area of ​​the second lens may be disposed on the object side of the second lens and may include the optical axis of the second lens.

[0028] Other features and aspects will become apparent from the following detailed description, the accompanying drawings and the appended claims. Attached Figure Description

[0029] Figure 1 This is a diagram illustrating a first example of an optical imaging system.

[0030] Figure 2 yes Figure 1 The aberration curves of the optical imaging system are shown in the figure.

[0031] Figure 3 This is a diagram illustrating a second example of an optical imaging system.

[0032] Figure 4 yes Figure 3 The aberration curves of the optical imaging system are shown in the figure.

[0033] Figure 5 This is a diagram illustrating a third example of an optical imaging system.

[0034] Figure 6 yes Figure 5 The aberration curves of the optical imaging system are shown in the figure.

[0035] Throughout the accompanying 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 dimensions, scale, and depiction of elements in the drawings may be exaggerated. Detailed Implementation

[0036] The following detailed description is provided to help the reader gain a full 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, and obvious changes can be made 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 herein. Rather, the examples described herein are provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein, which will be apparent upon understanding the disclosure of this application. In the following, although embodiments of this disclosure will be described in detail with reference to the accompanying drawings, it should be noted that the examples are not limited thereto.

[0038] Throughout this specification, when an element such as a layer, region, or substrate is described as being "on," "connected to," or "attached to" another element, the element may be directly "on," directly "connected to," or directly "attached to" the other element, or there may be one or more other elements between the element and the other element. Conversely, when an element is described as being "directly on," "directly connected to," or "directly attached 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; similarly, “at least one” includes any one of the associated listed items and any combination of any two or more items.

[0040] Although terms such as "first," "second," and "third" may be used in this application to describe various components, parts, regions, layers, or portions, these components, parts, regions, layers, or portions are not limited by these terms. Rather, these terms are used only to distinguish one component, part, region, layer, or portion from another. Therefore, without departing from the teachings of the examples described in this application, the first component, first part, first region, first layer, or first portion mentioned in those examples may also be referred to as a second component, second part, second region, second layer, or second portion.

[0041] Spatial relative terms such as “above,” “above,” “below,” and “under” may be used in this application for descriptive convenience to describe the relationship of one element relative to another, as shown in the accompanying drawings. In addition to covering the orientation depicted in the drawings, these spatial relative terms are intended to also cover different orientations of the device in use or operation. For example, if the device in the drawings is flipped, an element described as “above” or “above” relative to another element will be “below” or “under” that other element. Thus, depending on the spatial orientation of the device, the term “above” covers both “above” and “below” orientations. The device may also be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relative terms used in this application should be interpreted accordingly.

[0042] 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 plural forms as well. The terms “comprising,” “including,” and “having” indicate the presence of the stated features, numbers, operations, components, elements, and / or combinations thereof, but do not preclude 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 accompanying drawings may occur. Therefore, the examples described in this application are not limited to the specific shapes shown in the drawings, but include shape variations that occur during manufacturing.

[0044] The features of the examples described in this application can be combined in various ways that will become apparent after understanding the disclosure of this application. Furthermore, although the examples described in this application have multiple configurations, other configurations that will become apparent after understanding the disclosure of this application are also possible.

[0045] It should be noted that in this application, the use of the word "may" in relation to examples (e.g., regarding what an example may include or implement) means that there exists at least one example that includes or implements such a feature, but not all examples are limited thereto.

[0046] One aspect of this disclosure is to provide an optical imaging system that can be mounted on a portable terminal device and achieves a relatively high focal length ratio.

[0047] In this implementation, 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 plane (or image sensor). Furthermore, the radius of curvature, thickness, distance from the object-side surface of the first lens to the imaging plane (TL1), half-diagonal length of the imaging plane (IMGHT), and focal length of the lens are all expressed in millimeters (mm). Additionally, the lens thickness, the spacing between lenses, and TL1 are distances measured based on the optical axis of the lens. In the description of the lens surface type, a convex lens surface indicates that the optical axis region of the corresponding surface is convex, while a concave lens surface indicates that the optical axis region of the corresponding surface is concave. Therefore, in a configuration where the lens surface is described as convex, the edge region of the lens may be concave. Similarly, in a configuration where the lens surface is described as concave, the edge region of the lens may be convex.

[0048] In one embodiment, the optical imaging system may include four lenses arranged sequentially from the object side toward the imaging surface. For example, the optical imaging system may include a first lens, a second lens, a third lens, and a fourth lens arranged sequentially. The first to fourth lenses may be spaced at a specific interval. For example, a specific interval may be formed between the image-side surface of the first lens and the object-side surface of the second lens.

[0049] The first lens may have refractive power. For example, the first lens may have positive or negative refractive power.

[0050] The first lens may have a concave surface. For example, the first lens may have a convex object-side surface and / or a concave image-side surface. The first lens may have an aspherical surface. For example, the object-side surface and the image-side surface of the first lens may be aspherical. The first lens may be made of a material with high light transmittance and excellent processability. For example, the first lens may be made of plastic. However, the material of the first lens is not limited to plastic. The first lens may be made of, for example, glass.

[0051] The second lens may have refractive power. For example, the second lens may have positive or negative refractive power.

[0052] The second lens may have a convex surface. For example, the second lens may have a convex image-side surface. The second lens may have an aspherical surface. For example, the object-side and image-side surfaces of the second lens may be aspherical. The second lens may be made of a material with high light transmittance and excellent processability. For example, the second lens may be made of plastic. However, the material of the second lens is not limited to plastic. The second lens may be made of, for example, glass.

[0053] The second lens may include a region that reflects light. For example, a region on the object side of the second lens that includes the optical axis may be configured to reflect light incident from the image side of the second lens to the third lens.

[0054] The third lens may have refractive power. For example, the third lens may have positive or negative refractive power.

[0055] The third lens may have a concave surface. For example, the third lens may have a concave object-side surface. The third lens may have a spherical or aspherical surface. For example, one of the object-side and image-side surfaces of the third lens may be aspherical, or both of the object-side and image-side surfaces of the third lens may be spherical. The third lens may be made of a material with high light transmittance and excellent processability. For example, the third lens may be made of plastic. However, the material of the third lens is not limited to plastic. The third lens may be made of, for example, glass.

[0056] The third lens may include a region that reflects light. For example, a region outside the optical axis on the image-side surface of the third lens may be configured to reflect light incident from the first lens to the second lens. For example, the region that reflects light may be an edge region on the image-side surface of the third lens. For example, the region that reflects light may be located in the peripheral region of the image-side surface of the third lens to surround the optical axis, and spaced apart from the optical axis by a region on the image-side surface of the third lens that includes the optical axis, the region including the optical axis being configured to refract light incident from the second lens to the fourth lens.

[0057] The fourth lens may have refractive power. For example, the fourth lens may have negative refractive power.

[0058] The fourth lens may have a concave surface. For example, the fourth lens may have a concave object-side surface. The fourth lens may have an aspherical surface. For example, the object-side and image-side surfaces of the fourth lens may be aspherical. The fourth lens may be made of a material with high light transmittance and excellent processability. For example, the fourth lens may be made of plastic. However, the material of the fourth lens is not limited to plastic. The fourth lens may be made of, for example, glass.

[0059] The first through fourth lenses may include aspherical surfaces as described above. The aspherical surface of the lens can be represented by Equation 1 below.

[0060] Equation 1

[0061]

[0062] In Equation 1, c is the reciprocal of the radius of curvature of each lens, k is the conic constant, r is the distance from a point on the surface of the aspherical surface to the optical axis of the lens, A to J are aspherical constants, and Z (or sag) is the height from a point on the surface of the aspherical surface to the vertex of the corresponding aspherical surface in the direction of the optical axis.

[0063] The optical imaging system may also include an aperture stop. The aperture stop may be located in the front region of the first lens.

[0064] The optical imaging system may further include a filter. The filter may block specific wavelengths of light incident through the first lens to the fourth lens. For example, the filter may block infrared wavelengths of the incident light.

[0065] The optical imaging system may further include an image sensor. The image sensor may provide an imaging surface on which the light refracted by the lens may be imaged. For example, the surface of the image sensor may form the imaging surface. The image sensor may be configured to achieve a high level of resolution. The imaging surface of the image sensor may have a specific size. For example, the diagonal length of the imaging surface (IMGHT*2) may be less than the effective diameter of the first lens or the effective diameter of the third lens, and may be greater than the effective diameter of the second lens.

[0066] The optical imaging system may be configured such that the optical path can be increased without increasing the total length of the optical imaging system. For example, the light refracted by the first lens may be reflected from the edge portion of the third lens and may be incident on the second lens. The light incident on the second lens may be reflected from the object side surface of the second lens and may be incident on the paraxial region of the third lens. The light refracted in the paraxial region of the third lens may be refracted in the fourth lens and may be incident on the imaging surface.

[0067] The optical imaging system configured as above can quadruple the telephoto ratio without increasing the number of lenses or the distance between the lenses. Therefore, the optical imaging system can be effectively applied to portable terminal devices where the limitation range of the total length of the optical imaging system is relatively large.

[0068] The optical imaging system may satisfy at least one of the following first condition expression to fourth condition expression:

[0069] 0.1 < L1S1 / f < 0.95 (Condition Expression 1)

[0070] -0.95 < L2S1 / f < -0.1 (Condition Expression 2)

[0071] -1.5 < L3S1 / f < -0.2 (Condition Expression 3)

[0072] -1.55 < L3S2 / f < -0.25 (Condition Expression 4)

[0073] In addition, the optical imaging system may further satisfy at least one of the following fifth condition expression to seventh condition expression:

[0074] 2.0 < f / TL1 (Condition Expression 5)

[0075] 1.1 ≤ f / TL2 (Condition Expression 6)

[0076] TL2 / TL1<2.1 (Conditional expression 7)

[0077] In the above conditional expressions, "f" is the focal length of the optical imaging system, "L1S1" is the radius of curvature of the object-side surface of the first lens, "L2S1" is the radius of curvature of the object-side surface of the second lens, "L3S1" is the radius of curvature of the object-side surface of the third lens, "L3S2" is the radius of curvature of the image-side surface of the third lens, "TL1" is the total lens length of the optical imaging system (the distance from the object-side surface of the first lens to the image plane), and "TL2" is the total optical length of the optical imaging system (the sum of the propagation paths of refracted and reflected light between the object-side surface of the first lens and the image plane).

[0078] In the following description, an optical imaging system will be described according to one or more embodiments.

[0079] Reference Figure 1 The first example describing an optical imaging system.

[0080] Optical imaging system 100 may include multiple lenses with refractive power. For example, optical imaging system 100 may include a first lens 110, a second lens 120, a third lens 130, and a fourth lens 140. The first lens 110, second lens 120, third lens 130, and fourth lens 140 may be arranged sequentially and at intervals from the object side. However, the refraction and reflection of light may not occur in the order of the first lens 110, second lens 120, third lens 130, and fourth lens 140. For example, the refraction and reflection of light may occur in the order of the first lens 110, third lens 130, second lens 120, third lens 130, and fourth lens 140. In the following description, the shape of the lens will be described with reference to the order of refraction and reflection of light.

[0081] The first lens 110 may have positive refractive power and may have a convex object-side surface and a concave image-side surface. The first lens 110 configured as described above can refract light to the third lens 130.

[0082] The third lens 130 may have a concave object-side surface and a convex image-side surface. The third lens 130 may be configured to reflect and refract light. For example, the paraxial region of the third lens 130 may be configured to refract light, while the edge regions outside the paraxial region of the third lens 130 may be configured to reflect light. A reflecting region 1342 may be formed on the image-side surface 134 of the third lens 130. More specifically, the reflecting region 1342 may be formed on the edge region of the image-side surface 134 of the third lens 130. The reflecting region (or edge region) 1342 may be formed by coating the image-side surface of the third lens 130 with a reflective material. Other regions of the image-side surface of the third lens 130 may form refracting regions (or paraxial regions) 1344 for light refraction.

[0083] The second lens 120 may have a concave object-side surface and a concave image-side surface. The object-side surface 122 of the second lens 120 may form a reflective region. In this embodiment, the entire area of ​​the object-side surface 122 of the second lens 120 may be a reflective region. The entire area of ​​the image-side surface 124 of the second lens 120 may be configured to refract light. The second lens 120 configured as described above may be configured to reflect light reflected from the edge region of the third lens 130 to the paraxial region of the third lens 130. Light incident on the third lens 130 may be refracted in the paraxial region of the third lens 130 and may be incident on the fourth lens 140. More specifically, light reflected from the reflective region 1342 of the third lens 130 may be refracted by passing sequentially through the object-side surface 132 of the third lens 130 and the image-side surface 124 of the second lens 120, and may be reflected at the object-side surface 122 of the second lens 120. Light reflected from the object side 122 of the second lens 120 can be refracted through the paraxial region 1344 of the image side 124 of the second lens 120, the object side 132 of the third lens 130, and the image side 134 of the third lens 130, and can then be incident on the fourth lens 140.

[0084] The fourth lens 140 may have negative refractive power. The fourth lens 140 may have a concave object-side surface and a convex image-side surface. The fourth lens 140 configured as described above allows light refracted in the paraxial region of the third lens 130 to be incident on the imaging plane.

[0085] The optical imaging system 100 may also include an aperture stop ST. For example, the aperture stop ST may be located in the front region of the first lens 110.

[0086] The optical imaging system 100 may also include a filter 150. For example, the filter 150 may be disposed between the fourth lens 140 and the image sensor 160, and may prevent infrared light from incident on the imaging surface of the image sensor 160.

[0087] In the example of the optical imaging system 100 configured as described above, the focal length f can be 15.00 mm, the F number can be 2.770, the total lens length TL1 can be 5.85 mm, and the total optical length TL2 can be 11.83 mm.

[0088] The optical imaging system 100 in this embodiment may have, for example: Figure 2 The aberration characteristics are shown. Table 1 below lists the characteristics of the lenses included in the optical imaging system 100 of this embodiment.

[0089] Table 1

[0090]

[0091]

[0092] ("*" indicates that the corresponding surface is aspherical)

[0093] The surface numbers in the table above indicate the order of refraction and reflection of light incident on the optical imaging system. For example, surface 1 refers to the object-side surface 112 of the first lens, surface 2 refers to the image-side surface 114 of the first lens, surfaces 3, 5, and 9 refer to the object-side surface 132 of the third lens, surface 4 refers to the edge region 1342 of the image-side surface of the third lens, surface 10 refers to the paraxial region 1344 of the image-side surface of the third lens, surfaces 6 and 8 refer to the image-side surface 124 of the second lens, and surface 7 refers to the object-side surface 122 of the second lens. Surface 11 refers to the object-side surface 142 of the fourth lens, and surface 12 refers to the image-side surface 144 of the fourth lens.

[0094] Table 2 lists the characteristics of aspherical surfaces in optical imaging systems.

[0095] Table 2

[0096] Face number K A B C D E F G 1 0 -1.21E-03 -1.78E-04 -6.11E-05 1.36E-06 0 0 0 2 0 -2.78E-04 -1.69E-04 -7.39E-05 3.24E-06 0 0 0 3 0 9.26E-05 -2.37E-05 -1.17E-06 9.45E-08 0 0 0 4 0 -1.64E-04 -1.11E-05 0 0 0 0 0 5 0 9.26E-05 -2.37E-05 -1.17E-06 9.45E-08 0 0 0 6 0 3.91E-03 -2.23E-03 3.73E-04 -2.77E-06 0 0 0 7 0 -2.92E-03 -1.46E-03 0 0 0 0 0 8 0 3.91E-03 -2.23E-03 3.73E-04 -2.77E-06 0 0 0 9 0 9.26E-05 -2.37E-05 -1.17E-06 9.45E-08 0 0 0 10 0 -1.64E-04 -1.11E-05 0 0 0 0 0 11 0 -4.50E-02 1.52E-02 -2.50E-03 1.61E-04 1.65E-05 -2.20E-06 0 12 0 -7.03E-02 2.50E-02 -4.56E-03 3.82E-04 4.02E-06 -1.76E-06 0

[0097] In the following description, reference will be made to Figure 3 A second example describing an optical imaging system.

[0098] Optical imaging system 200 may include multiple lenses with refractive power. For example, optical imaging system 200 may include a first lens 210, a second lens 220, a third lens 230, and a fourth lens 240. The first lens 210, second lens 220, third lens 230, and fourth lens 240 may be arranged sequentially and at intervals from the object side. However, the refraction and reflection of light may not occur in the order of the first lens 210, second lens 220, third lens 230, and fourth lens 240. For example, the refraction and reflection of light may occur in the order of the first lens 210, third lens 230, second lens 220, third lens 230, and fourth lens 240. In the following description, the shape of the lens will be described with reference to the order of refraction and reflection of light.

[0099] The first lens 210 may have positive refractive power and may have a convex object-side surface and a concave image-side surface. The first lens 210 configured as described above can refract light to the third lens 230.

[0100] The third lens 230 may have a concave object-side surface and a convex image-side surface. The third lens 230 may be configured to reflect and refract light. For example, the paraxial region of the third lens 230 may be configured to refract light, while the edge regions outside the paraxial region of the third lens 230 may be configured to reflect light. A reflecting region 2342 may be formed on the image-side surface 234 of the third lens 230. More specifically, the reflecting region 2342 may be formed on the edge region of the image-side surface 234 of the third lens 230. The reflecting region (or edge region) 2342 may be formed by coating the image-side surface of the third lens 230 with a reflective material. Other regions of the image-side surface of the third lens 230 may form refracting regions (or paraxial regions) 2344 for light refraction.

[0101] The second lens 220 may have a concave object-side surface and a convex image-side surface. The object-side surface 222 of the second lens 220 may form a reflective region. In this embodiment, the entire area of ​​the object-side surface 222 of the second lens 220 may be a reflective region. The entire area of ​​the image-side surface 224 of the second lens 220 may be configured to refract light. The second lens 220 configured as described above may be configured to reflect light reflected from the edge region of the third lens 230 to the paraxial region of the third lens 230. Light incident on the third lens 230 may be refracted in the paraxial region of the third lens 230 and may be incident on the fourth lens 240. More specifically, light reflected from the reflective region 2342 of the third lens 230 may be refracted by passing sequentially through the object-side surface 232 of the third lens 230 and the image-side surface 224 of the second lens 220, and may be reflected at the object-side surface 222 of the second lens 220. Light reflected from the object side 222 of the second lens 220 can be refracted through the paraxial region 2344 of the image side 224 of the second lens 220, the object side 232 of the third lens 230, and the image side 234 of the third lens 230, and can then be incident on the fourth lens 240.

[0102] The fourth lens 240 may have negative refractive power. The fourth lens 240 may have a concave object-side surface and a convex image-side surface. The fourth lens 240 configured as described above allows light refracted from the paraxial region of the third lens 230 to be incident on the imaging plane.

[0103] The optical imaging system 200 may also include an aperture stop ST. For example, the aperture stop ST may be located in the front region of the first lens 210.

[0104] The optical imaging system 200 may also include a filter 250. For example, the filter 250 may be disposed between the fourth lens 240 and the image sensor 260, and may prevent infrared light from incident on the imaging surface of the image sensor 260.

[0105] In the example of the optical imaging system 200 configured as described above, the focal length f can be 15.00mm, the F number can be 2.770, the total lens length TL1 can be 6.00mm, and the total optical length TL2 can be 12.02mm.

[0106] The optical imaging system 200 in this embodiment may have, for example: Figure 4 The aberration characteristics are shown. Table 3 below lists the characteristics of the lenses included in the optical imaging system 200 of this embodiment.

[0107] Table 3

[0108]

[0109] ("*" indicates that the corresponding surface is aspherical)

[0110] The surface numbers in the table above indicate the order of refraction and reflection of light incident on the optical imaging system. For example, surface 1 refers to the object-side surface 212 of the first lens, surface 2 refers to the image-side surface 214 of the first lens, surfaces 3, 5, and 9 refer to the object-side surface 232 of the third lens, surface 4 refers to the edge region 2342 of the image-side surface of the third lens, surface 10 refers to the paraxial region 2344 of the image-side surface of the third lens, surfaces 6 and 8 refer to the image-side surface 224 of the second lens, and surface 7 refers to the object-side surface 222 of the second lens. Surface 11 refers to the object-side surface 242 of the fourth lens, and surface 12 refers to the image-side surface 244 of the fourth lens.

[0111] Table 4 lists the characteristics of aspherical surfaces in optical imaging systems.

[0112] Table 4

[0113] Face number K A B C D E F G 1 0 -1.99E-03 -2.63E-04 -1.24E-05 -2.23E-06 0 0 0 2 0 -1.62E-03 -2.02E-04 -3.14E-05 -1.96E-07 0 0 0 3 0 1.50E-04 1.22E-05 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 1.50E-04 1.22E-05 0 0 0 0 0 6 0 1.09E-02 8.85E-04 1.68E-04 -4.57E-05 0 0 0 7 0 2.70E-03 4.00E-04 0 0 0 0 0 8 0 1.09E-02 8.85E-04 1.68E-04 -4.57E-05 0 0 0 9 0 1.50E-04 1.22E-05 0 0 0 0 0 10 0 0 0 0 0 0 0 0 11 0 2.47E-02 -1.64E-04 -1.01E-03 2.56E-04 0 0 0 12 0 -3.64E-02 1.05E-02 -2.23E-03 1.62E-04 0 0 0

[0114] The following description will depict a third example of an optical imaging system.

[0115] The optical imaging system 300 may include a plurality of lenses having refractive power. For example, the optical imaging system 300 may include a first lens 310, a second lens 320, a third lens 330, and a fourth lens 340. The first lens 310, the second lens 320, the third lens 330, and the fourth lens 340 may be arranged sequentially and at intervals from the object side. However, the refraction and reflection of light may not occur in the order of the first lens 310, the second lens 320, the third lens 330, and the fourth lens 340. For example, the refraction and reflection of light may occur in the order of the first lens 310, the third lens 330, the second lens 320, the third lens 330, and the fourth lens 340. In the following description, the shape of the lens will be described with reference to the order of refraction and reflection of light.

[0116] The first lens 310 may have positive refractive power and may have a convex object-side surface and a concave image-side surface. The first lens 310 configured as described above can refract light to the third lens 330.

[0117] The third lens 330 may have a concave object-side surface and a convex image-side surface. The third lens 330 may be configured to reflect and refract light. For example, the paraxial region of the third lens 330 may be configured to refract light, while the edge regions outside the paraxial region of the third lens 330 may be configured to reflect light. A reflecting region 3342 may be formed on the image-side surface 334 of the third lens 330. More specifically, the reflecting region 3342 may be formed on the edge region of the image-side surface 334 of the third lens 330. The reflecting region (or edge region) 3342 can be formed by coating the image-side surface of the third lens 330 with a reflective material. Other regions of the image-side surface of the third lens 330 may form refracting regions (or paraxial regions) 3344 for light refraction.

[0118] The second lens 320 may have a concave object-side surface and a convex image-side surface. The object-side surface 322 of the second lens 320 may form a reflective region. In this embodiment, the entire area of ​​the object-side surface 322 of the second lens 320 may be a reflective region. The entire area of ​​the image-side surface 324 of the second lens 320 may be configured to refract light. The second lens 320 configured as described above may be configured to reflect light reflected from the edge region of the third lens 330 to the paraxial region of the third lens 330. Light incident on the third lens 330 may be refracted in the paraxial region of the third lens 330 and may be incident on the fourth lens 340. More specifically, light reflected from the reflective region 3342 of the third lens 330 may be refracted by passing sequentially through the object-side surface 332 of the third lens 330 and the image-side surface 324 of the second lens 320, and may be reflected at the object-side surface 322 of the second lens 320. Light reflected from the object side 322 of the second lens 320 can be refracted through the paraxial region 3344 of the image side 324 of the second lens 320, the object side 332 of the third lens 330, and the image side 334 of the third lens 330, and can then be incident on the fourth lens 340.

[0119] The fourth lens 340 may have negative refractive power. The fourth lens 340 may have a concave object-side surface and a convex image-side surface. The fourth lens 340 configured as described above allows light refracted from the paraxial region of the third lens 330 to be incident on the imaging plane.

[0120] The optical imaging system 300 may also include an aperture stop ST. For example, the aperture stop ST may be located in the front region of the first lens 310.

[0121] The optical imaging system 300 may also include a filter 350. For example, the filter 350 may be disposed between the fourth lens 340 and the image sensor 360, and may prevent infrared light from incident on the imaging surface of the image sensor 360.

[0122] In the example of the optical imaging system 300 configured as described above, the focal length f can be 15.00mm, the F number can be 2.770, the total lens length TL1 can be 6.50mm, and the total optical length TL2 can be 12.60mm.

[0123] The optical imaging system 300 in this embodiment may have, for example: Figure 6 The aberration characteristics are shown. Table 5 below lists the characteristics of the lenses included in the optical imaging system 300 in this embodiment.

[0124] Table 5

[0125]

[0126] ("*" indicates that the corresponding surface is aspherical)

[0127] The surface numbers in the table above indicate the order of refraction and reflection of light incident on the optical imaging system. For example, surface 1 refers to the object-side surface 312 of the first lens, surface 2 refers to the image-side surface 314 of the first lens, surfaces 3, 5, and 9 refer to the object-side surface 332 of the third lens, surface 4 refers to the edge region 3342 of the image-side surface of the third lens, surface 10 refers to the paraxial region 3344 of the image-side surface of the third lens, surfaces 6 and 8 refer to the image-side surface 324 of the second lens, and surface 7 refers to the object-side surface 322 of the second lens. Surface 11 refers to the object-side surface 342 of the fourth lens, and surface 12 refers to the image-side surface 344 of the fourth lens.

[0128] Table 6 lists the characteristics of aspherical surfaces in optical imaging systems.

[0129] Table 6

[0130] Face number K A B C D E F G 1 0 -2.70E-03 -2.47E-04 5.50E-07 -1.10E-06 0 0 0 2 0 -2.64E-03 -2.27E-04 -3.23E-06 -5.54E-07 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 -1.13E-02 3.49E-03 0 0 0 0 0 7 0 -4.83E-03 1.59E-03 0 0 0 0 0 8 0 -1.13E-02 3.49E-03 0 0 0 0 0 9 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 11 0 2.11E-02 -8.77E-03 2.31E-03 1.15E-04 0 0 0 12 0 5.51E-03 -1.11E-02 2.82E-03 -2.49E-04 0 0 0

[0131] Table 7 shows the values ​​of the conditional expressions for the first, second, and third examples of the optical imaging system. As shown in Table 7, the first to third examples of the optical imaging system can satisfy all numerical ranges of the above conditional expressions.

[0132] Table 7

[0133] conditional expression First Example Second example Third Example L1S1 / f 0.3246 0.2867 0.3985 L2S1 / f -0.4213 -0.4455 -0.5002 L3S1 / f -0.6097 -0.6537 -0.6877 L3S2 / f -0.6284 -0.7107 -0.7410 TL2 / TL1 2.0222 2.0033 1.9385 f / TL1 2.5641 2.5000 2.3077 f / TL2 1.2680 1.2479 1.1905

[0134] According to the aforementioned embodiments, an optical imaging system suitable for small-sized cameras with high performance can be realized.

[0135] While specific examples have been shown and described above, 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. The description 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, apparatus, 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 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 this disclosure.

Claims

1. An optical imaging system comprising a total of four lenses with refractive power, the four lenses with refractive power being, in order from the object side: The first lens has positive refractive power, a convex object-side surface, and a concave image-side surface; The second lens has refractive power and a concave object-side surface, and includes a first reflective region formed on the object-side surface of the second lens; The third lens has refractive power, a concave object side and a convex image side, and includes a second reflection region formed on the image side of the third lens and a refractive region formed on the image side of the third lens. and The fourth lens has negative refractive power, a concave object-side surface, and a convex image-side surface. In this process, incident light from the object side is refracted by the first lens, reflected by the second reflection region of the third lens, reflected by the first reflection region of the second lens, refracted by the refractive region of the third lens, and refracted by the fourth lens to form an image in this order.

2. The optical imaging system of claim 1, wherein, The first reflective region is configured to include the optical axis of the second lens.

3. The optical imaging system of claim 1, wherein, The second reflective region is formed in the area outside the optical axis of the third lens.

4. The optical imaging system according to claim 3, wherein, The second reflective region surrounds the optical axis and is spaced apart from the optical axis by a refractive region formed on the image side of the third lens, wherein the refractive region includes the optical axis of the third lens.

5. The optical imaging system according to claim 1, wherein, The second lens has an effective diameter smaller than that of the first lens and the third lens.

6. The optical imaging system according to claim 1, wherein, The optical imaging system satisfies the following conditional expression: 1.1 ≤ f / TL2 Where f is the focal length of the optical imaging system, and TL2 is the total optical length of the optical imaging system.

7. The optical imaging system according to claim 6, wherein, The optical imaging system satisfies the following conditional expression: TL2 / TL1 < 2.1 Wherein, TL1 is the total lens length of the optical imaging system, and TL2 is the total optical length of the optical imaging system.

8. The optical imaging system according to claim 6, wherein, The optical imaging system satisfies one or more of the following conditional expressions: 0.1 < L1S1 / f < 0.95; -0.95 < L2S1 / f < -0.1; -1.5 < L3S1 / f < -0.2; -1.55 < L3S2 / f < -0.25; Wherein, L1S1 is the radius of curvature of the object-side surface of the first lens, L2S1 is the radius of curvature of the object-side surface of the second lens, L3S1 is the radius of curvature of the object-side surface of the third lens, and L3S2 is the radius of curvature of the image-side surface of the third lens.

Images