Optical system

Abstract

An optical system disclosed according to an embodiment of the present application includes an optical path changing member and a plurality of lenses disposed in order from an object side toward an image side along an optical axis. The optical path changing member includes a reflector or a prism, and the intervals between the plurality of lenses do not change. The lens closest to the image side among the plurality of lenses can have a larger effective aperture than the other lenses.

Description

Technical Field

[0001] Embodiments of the present invention relate to optical devices for improving optical performance. Background Technology

[0002] Camera module captures objects and stores them as images or videos, and is installed in a variety of applications. In particular, camera modules are manufactured in very small sizes and are used not only in portable devices such as smartphones, tablet PCs, and laptops, but also in drones and vehicles offering various functions. For example, the optical system of a camera module may include an imaging lens for forming an image and an image sensor for converting the formed image into an electrical signal. In this case, the camera module can perform autofocus (AF) by automatically adjusting the distance between the image sensor and the imaging lens to align the focal length of the lens, and can perform zoom functions by increasing or decreasing the magnification of a remote object via a zoom lens. Furthermore, the camera module employs image stabilization (IS) technology to correct or prevent image stabilization caused by unstable fixed equipment or camera movement due to user movement. The most important element for the camera module to acquire images is the imaging lens that forms the image. Recently, there has been increasing interest in high efficiency and high image quality, high resolution, and research is underway on optical systems including multiple lenses to achieve this. For example, research is underway to achieve efficient optical systems using multiple imaging lenses with positive (+) and / or negative (-) refractive power. However, when multiple lenses are included, it is difficult to obtain excellent optical and aberration characteristics.

[0003] As the back focal length (BFL) of an optical system increases, light incident on the optical system is reflected on the inner surface of the instrument containing the optical system, potentially resulting in phenomena such as flares or ghosting. Therefore, a new optical system capable of addressing these problems is needed. Summary of the Invention

[0004] Technical issues

[0005] The implementation provides an optical system with improved optical properties.

[0006] The implementation provides an optical system with improved telescope performance.

[0007] Technical solutions

[0008] An optical system according to an embodiment of the present invention includes an optical path changing member and a plurality of lenses arranged sequentially along an optical axis from the object side toward the image side. The optical path changing member includes a mirror or a prism, and the distance between the plurality of lenses remains unchanged. The effective aperture of the lens closest to the image side among the plurality of lenses is larger than the effective aperture of the other lenses.

[0009] According to an embodiment of the present invention, a plurality of lenses may include a first lens to a fifth lens arranged sequentially along the optical axis in a direction from the object side to the image side. The effective aperture size of each of the first lens and the fifth lens may satisfy Equation 1 below.

[0010] [Formula 1]

[0011] 0.8 <CA11 / CA51<2

[0012] 0.8 <CA12 / CA52<2

[0013] (In Equation 1, CA11 represents the effective aperture size on the object-side surface of the first lens, and CA12 represents the effective aperture size on the image-side surface of the first lens. Furthermore, CA51 represents the effective aperture size on the object-side surface of the fifth lens, and CA52 represents the effective aperture size on the image-side surface of the fifth lens.)

[0014] According to an embodiment of the present invention, the effective aperture size of the first lens can be the largest among the effective aperture sizes of the first to fourth lenses. When the distance from the image side surface of the fifth lens to the image sensor in the optical axis direction is defined as the back focal length (BFL), the following Equation 2 can be satisfied.

[0015] [Equation 2]

[0016] 0 <CA / BFL<1

[0017] (In Equation 2, CA is the size of the effective aperture of the object-side or image-side surface of a lens selected from the first to the fifth lens.)

[0018] According to an embodiment of the present invention, when the distance from the object-side surface of the first lens to the image sensor in the optical axis direction is defined as the total track length (TTL), the following equation 3 can be satisfied.

[0019] [Formula 3]

[0020] 3 <TTL / BFL<4.5

[0021] According to an embodiment of the present invention, the effective focal length (EFL) of the optical system can be greater than 10 mm. The optical system can have an F-number of less than 3.8. The principal ray incident angle (CRA) of the optical system can be less than 40 degrees. The first lens can have positive (+) refractive power. The fifth lens can have positive refractive power. The object-side surface of the third lens can have an inflection point.

[0022] An optical system according to an embodiment of the present invention includes an optical path changing component, a plurality of lenses, and an image sensor arranged sequentially along the optical axis from the object side to the image side. The optical path changing component includes a mirror or a prism. When the distance between the plurality of lenses does not change and the distance from the image-side surface of the lens closest to the image sensor in the optical axis direction to the image sensor is defined as BFL (back focal length), the following Equation 4 can be satisfied.

[0023] [Formula 4]

[0024] 0.5 <ImgH / BFL<1.5

[0025] (In Equation 4, ImgH represents half the diagonal length of the effective area of ​​the image sensor.)

[0026] Beneficial effects

[0027] The optical system according to embodiments of the present invention can have improved optical characteristics. Specifically, the optical system may include multiple lenses, and the effective aperture of the last lens closest to the image sensor may be larger than the effective aperture of the first lens closest to the object side. In particular, the effective aperture of the last lens may be the largest among the multiple lenses, thus improving optical characteristics can be obtained when designing zoom lenses for image sensors of various sizes (e.g., from small to large).

[0028] The optical system according to embodiments of the present invention can minimize or prevent the occurrence of phenomena such as flare and ghosting. Specifically, the optical system can have a relatively small BFL value. Therefore, the reflection of light incident on the optical system at the structure between the last lens and the image sensor can be minimized or prevented. Furthermore, the optical system can easily correct the CRA (lead ray angle) value, thus it can have improved optical characteristics. Attached Figure Description

[0029] Figure 1 This is a configuration diagram of the optical system according to the implementation method.

[0030] Figure 2 It is a graph showing the aberration diagram of the optical system according to the embodiment. Detailed Implementation

[0031] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings. However, the spirit of the invention is not limited to the embodiments described, and it can be implemented in various other forms, and one or more components can be selectively combined and substituted for use within the scope of the spirit of the invention. Furthermore, unless specifically defined and explicitly described, the terminology used in the embodiments of the invention (including technical and scientific terms) can be interpreted in the sense commonly understood by one of ordinary skill in the art to which this invention pertains, and commonly used terms (e.g., terms defined in dictionaries) should be interpretable in light of the contextual meaning of the relevant art.

[0032] The terminology used in embodiments of the present invention is for illustrative purposes and is not intended to limit the invention. In this specification, unless specifically stated otherwise in the phrase, the singular form may also include the plural form, and in cases describing at least one (or one or more) of A and / or B, C, it may include one or more of all combinations that can be combined with A, B, and C. When describing components of embodiments of the invention, terms such as first, second, A, B, (a), and (b) may be used. Such terms are used only to distinguish a component from other components and are not determined by terms describing the nature, order, or procedure of the corresponding constituent elements. Furthermore, when describing a component as “connected,” “coupled,” or “joined” to another component, the description may include not only direct connection, coupling, or joining to other components but also connection, coupling, or joining between that component and other components via another component. Additionally, when described as being formed or disposed “above” or “below” each component, the description may include not only cases where two components are in direct contact with each other but also cases where one or more other components are formed or disposed between the two components. Additionally, when expressed as "above" or "below", it can refer to the downward and upward directions relative to a component.

[0033] In the description of this invention, a convex surface of a lens can refer to a lens surface in the region corresponding to the optical axis having a convex shape, and a concave surface of a lens can refer to a lens surface in the region corresponding to the optical axis having a concave shape. Furthermore, "object-side surface" can refer to the surface of the lens facing the object side relative to the optical axis, and "image-side surface" can refer to the surface of the lens facing the imaging surface relative to the optical axis. Additionally, the vertical direction can refer to a direction perpendicular to the optical axis, and the end of the lens or lens surface can refer to the outermost end of the effective region of the lens through which the incident light passes.

[0034] Figure 1It is a configuration diagram of the optical system according to the implementation method, and Figure 2 It is a graph showing the aberration diagram of the optical system according to the embodiment.

[0035] Reference Figure 1 The optical system 1000 according to an embodiment of the present invention may include a plurality of lenses. For example, the optical system 1000 may include four or more lenses. More specifically, the optical system 1000 may include five or more lenses.

[0036] The optical system 1000 may include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, and a fifth lens 150 arranged sequentially from the object side to the image side. The optical system 1000 may include a filter 500 and an image sensor 300 in the direction above the plurality of lenses 110, 120, 130, 140, and 150. The first to fifth lenses 110, 120, 130, 140, and 150 may be arranged sequentially along the optical axis of the optical system 1000. Light corresponding to the image information of the object may pass sequentially through the first to fifth lenses 110, 120, 130, 140, and 150 and be incident on the image sensor 300.

[0037] The optical system 1000 may further include an optical path changing member 50. The optical path changing member 50 can change the path of light by reflecting externally incident light. The optical path changing member 50 may include a mirror or a prism. For example, the optical path changing member 50 may include a right-angle prism. When the optical path changing member 50 includes a right-angle prism, the optical path changing member 50 can change the path of incident light by reflecting it at a 90-degree angle. The optical path changing member 50 may be positioned closer to the object side than the first to fifth lenses 110, 120, 130, 140, and 150. That is, the optical system 1000 includes the optical path changing member 50, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, a filter 500, and an image sensor 300, arranged sequentially along the optical axis OA from the object side toward the image side. The optical path changing member 50 can change the path of light in a set direction by reflecting externally incident light. That is, the optical path changing member 50 can change the path of the light incident on the optical path changing member 50 toward the first lens to the fifth lens 110, 120, 130, 140 and 150.

[0038] Each of the first to fifth lenses 110, 120, 130, 140, and 150 may include an effective region and an ineffective region. The effective region may be the area through which light incident on the lens passes. That is, the effective region may be the area where incident light is refracted to achieve optical properties. The ineffective region may be arranged around the effective region. The ineffective region may be the area where light is not incident. That is, the ineffective region may be the area unrelated to optical properties. Furthermore, the ineffective region may be the area fixed to a lens barrel (not shown) housing the lens. An optical system 1000 according to an embodiment of the present invention may include an aperture stop 200 for adjusting the amount of incident light. The aperture stop 200 may be disposed between two lenses selected from the first to fifth lenses 110, 120, 130, 140, and 150. For example, the aperture stop 200 may be disposed between the first lens 110 and the second lens 120. At least one of the first to fifth lenses 110, 120, 130, 140, and 150 may be used as an aperture stop. For example, a lens surface selected from the first to the fifth lenses 110, 120, 130, 140 and 150 can be used as an aperture stop to adjust the amount of light incident on the optical system 1000.

[0039] The filter 500 may include at least one of an infrared filter and a filter such as a cover glass. The filter 500 allows light of a defined wavelength band to pass through and filters light of different wavelength bands. When the filter 500 includes an infrared filter, it can prevent radiative heat emitted from external light from being transferred to the image sensor 300. Furthermore, the filter 500 can transmit visible light and reflect infrared light.

[0040] Image sensor 300 can detect light. Specifically, image sensor 300 can detect light passing sequentially through first lenses to fifth lenses 110, 120, 130, 140, and 150. Image sensor 300 may include a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS).

[0041] The following text will describe several lenses in detail.

[0042] The first lens 110 may have positive (+) refractive power. The first lens 110 may comprise a plastic or glass material. For example, the first lens 110 may be made of a plastic material. The first lens 110 may comprise a first surface S1 defined as an object-side surface and a second surface S2 defined as an image-side surface. The first surface S1 may be convex, and the second surface S2 may also be convex. That is, the first lens 110 may have convex shapes on both sides. At least one of the first surface S1 and the second surface S2 may be aspherical. For example, both the first surface S1 and the second surface S2 may be aspherical.

[0043] The second lens 120 may have negative (-) refractive power. The second lens 120 may comprise a plastic or glass material. For example, the second lens 120 may be made of a plastic material. The second lens 120 may include a third surface S3 defined as an object-side surface and a fourth surface S4 defined as an image-side surface. The third surface S3 may be concave, and the fourth surface S4 may be convex. That is, the second lens 120 may have a meniscus shape convex toward the image side. At least one of the third surface S3 and the fourth surface S4 may be aspherical. For example, both the third surface S3 and the fourth surface S4 may be aspherical.

[0044] The third lens 130 may have negative (-) refractive power. The third lens 130 may comprise a plastic or glass material. For example, the third lens 130 may be made of a plastic material. The third lens 130 may comprise a fifth surface S5 defined as the object-side surface and a sixth surface S6 defined as the image-side surface. The fifth surface S5 may be concave, and the sixth surface S6 may also be concave. That is, the third lens 130 may have concave shapes on both sides. Additionally, the third lens 130 may have an inflection point. Specifically, the inflection point may be formed on the fifth surface S5 of the third lens 130. At least one of the fifth surface S5 and the sixth surface S6 may be aspherical. For example, both the fifth surface S5 and the sixth surface S6 may be aspherical.

[0045] The fourth lens 140 may have positive (+) refractive power. The fourth lens 140 may comprise a plastic or glass material. For example, the fourth lens 140 may be made of a plastic material. The fourth lens 140 may include a seventh surface S7 defined as the object-side surface and an eighth surface S8 defined as the image-side surface. The seventh surface S7 may be convex, and the eighth surface S8 may be concave. That is, the fourth lens 140 may have a meniscus shape convex toward the object side. At least one of the seventh surface S7 and the eighth surface S8 may be aspherical. For example, both the seventh surface S7 and the eighth surface S8 may be aspherical.

[0046] The fifth lens 150 may have positive (+) refractive power. The fifth lens 150 may comprise a plastic or glass material. For example, the fifth lens 150 may be made of a plastic material. The fifth lens 150 may include a ninth surface S9 defined as the object-side surface and a tenth surface S10 defined as the image-side surface. The ninth surface S9 may be convex or concave. That is, the fifth lens 150 may have a meniscus shape convex toward the object side. At least one of the ninth surface S9 and the tenth surface S10 may be aspherical. For example, both the ninth surface S9 and the tenth surface S10 may be aspherical.

[0047] The first to fifth lenses 110, 120, 130, 140 and 150 may have a defined effective aperture (e.g., a clear aperture). For example, each of the first to tenth surfaces S1, S2, S3, S4, S5, S6, S7, S8, S9 and S10 may have a defined effective aperture.

[0048] Among the first to fifth lenses 110, 120, 130, 140, and 150, the effective aperture of the fifth lens 150, which is closest to the image sensor 300, can be larger than the effective apertures of the first to fourth lenses 110, 120, 130, and 140. For example, the effective apertures of the ninth surface S9 and the tenth surface S10 of the fifth lens 150 can be larger than the effective apertures of the first surface to the eighth surface S1, S2, S3, S4, S5, S6, S7, and S8. The first lens 110 can have the largest effective aperture among the first to fourth lenses 110, 120, 130, and 140. For example, the effective apertures of the first surface S1 and the second surface S2 of the first lens 110 can be larger than the effective apertures of the third surface to the eighth surface S3, S4, S5, S6, S7, and S8.

[0049] The effective aperture of the second lens 120 can be larger than the effective apertures of the third lens 130 and the fourth lens 140. For example, the effective apertures of the third surface S3 and the fourth surface S4 of the second lens 120 can be larger than the effective apertures of the fifth to eighth surfaces S5, S6, S7, and S8 of the third lens 130 and the fourth lens 140. The effective aperture of the fourth lens 140 can be larger than the effective aperture of the third lens 130. For example, the effective apertures of the seventh surface S7 and the eighth surface S8 of the fourth lens 140 can be larger than the effective apertures of each of the fifth surface S5 and the sixth surface S6 of the third lens 130.

[0050] The optical system 1000 according to an embodiment of the present invention can satisfy at least one of the following formulas. Therefore, when the optical system 1000 according to the embodiment satisfies at least one of the following formulas, it can have improved optical characteristics.

[0051] [Formula 1]

[0052] 0.8 <CA11 / CA51<2

[0053] 0.8 <CA12 / CA52<2

[0054] In Equation 1, CA11 represents the effective aperture size of the object-side surface (first surface S1) of the first lens 110, and CA12 represents the effective aperture size of the image-side surface (second surface S2) of the first lens 110. Furthermore, CA51 represents the effective aperture size of the object-side surface (ninth surface S9) of the fifth lens 150, and CA52 represents the effective aperture size of the image-side surface (tenth surface S10) of the fifth lens 150.

[0055] In detail, the effective aperture of the first lens 110 and the effective aperture of the fifth lens 150 can satisfy the following equation 1-1.

[0056] [Equation 1-1]

[0057] 0.8 <CA11 / CA51<1.8

[0058] 0.8 <CA12 / CA52<1.8

[0059] More specifically, the effective aperture of the first lens 110 and the effective aperture of the fifth lens 150 can satisfy the following equations 1-2.

[0060] [Equation 1-2]

[0061] 0.8 <CA11 / CA51<1.5

[0062] 0.8 <CA12 / CA52<1.5

[0063] [Equation 2]

[0064] 0 <CA / BFL<1

[0065] In Equation 2, CA represents the size of the effective aperture of the object-side or image-side surface of any of the lenses selected from the first lens to the fifth lens 110, 120, 130, 140, and 150. Furthermore, BFL (back focal length) refers to the distance along the optical axis from the image-side surface (tenth surface S10) of the fifth lens 150 to the image sensor 300.

[0066] In detail, the effective aperture and BFL of the first to fifth lenses 110, 120, 130, 140 and 150 can satisfy the following equation 2-1.

[0067] [Equation 2-1]

[0068] 0.3 <CA / BFL<1

[0069] More specifically, the effective apertures and BFL of the first to fifth lenses 110, 120, 130, 140 and 150 can satisfy Equation 2-2 below.

[0070] [Equation 2-2]

[0071] 0.3 <CA / BFL<0.8

[0072] [Formula 3]

[0073] 3 <TTL / BFL<5

[0074] In Equation 3, the total track length (TTL) represents the distance from the object-side surface (first surface S1) of the first lens 110 to the image sensor 300 in the optical axis direction.

[0075] [Formula 4]

[0076] 0.5 <ImgH / BFL<1.5

[0077] In Equation 4, ImgH represents half the length of the effective area of ​​the image sensor 300 in the diagonal direction. That is, ImgH represents the distance in the vertical direction from the optical axis of the upper surface of the image sensor 300 to the region of field 1.

[0078] More specifically, ImgH and BFL can satisfy the following equation 4-1.

[0079] [Equation 4-1]

[0080] 0.5 <ImgH / BFL<1

[0081] [Formula 5]

[0082] EFL>10mm

[0083] In Equation 5, EFL represents the effective focal length of the optical system 1000.

[0084] [Formula 6]

[0085] F-number < 3.8

[0086] In Equation 6, F-number represents the numerical value of the brightness of the optical system.

[0087] [Formula 7]

[0088] CRA <40

[0089] In Equation 7, CRA (principal ray angle) represents the incident angle of the principal ray incident on the image sensor 300.

[0090] [Formula 8]

[0091] 2 <CT1 / CT5<4

[0092] In Equation 8, CT1 represents the thickness of the center of the first lens 110, and CT5 represents the thickness of the center of the fifth lens 150.

[0093] [Formula 9]

[0094] |f5|>|f1|+|f2|+|f3|+|f4|

[0095] In Equation 9, f1 to f5 represent the focal lengths of the first to fifth lenses 110, 120, 130, 140, and 150, respectively. The absolute value of the focal length f5 of the fifth lens 150 can be greater than the sum of the absolute values ​​of the focal lengths f1, f2, f3, and f4 of the first to fourth lenses 110, 120, 130, and 140.

[0096] [Formula 10]

[0097] 20 <f5 / EFL<50

[0098] In Equation 10, f5 represents the focal length of the fifth lens 150, and EFL represents the effective focal length of the optical system 1000.

[0099] [Equation 11]

[0100]

[0101] In Equation 10, Z is the Sag value and can represent the distance from any position on the aspherical surface to the vertex of the aspherical surface along the optical axis. Furthermore, Y can represent the distance from any position on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. Additionally, c can represent the curvature of the lens, and K can represent the conic constant. Furthermore, A, B, C, D, E, and F can represent aspherical constants.

[0102] The optical system 1000 according to the embodiment can satisfy at least one of Equations 1 to 9. In this case, the optical system 1000 can have improved optical characteristics. In detail, when the optical system 1000 satisfies at least one of the above equations, it can prevent the occurrence of characteristic degradation phenomena, such as flare or ghosting, that occur when light incident on the optical system 1000 is reflected by the mechanism housing the optical system 1000.

[0103] Table 1 shows data for the lens according to an embodiment of the present invention.

[0104] [Table 1]

[0105]

[0106]

[0107] Table 2 below shows the characteristics of the optical system and lens according to an embodiment of the present invention.

[0108] [Table 2]

[0109] item Implementation TTL 11.08676 F-number 3.4647 EFL 10.7407 BFL 2.818 ImgH 2.051 f1 5.256428 f2 -11.58088 f3 -9.65706 f4 43.734218 f5 428.46201

[0110] Table 1 shows the radius of curvature, thickness (mm) of each lens, distance between lenses (mm), refractive index, and Abbe number of the first to fifth lenses 110, 120, 130, 140, and 150. Referring to Table 1, the refractive indices of the first lens 110, third lens 130, and fifth lens 150 can be equal to each other, and the refractive indices of the second lens 120 and fourth lens 140 can also be equal to each other. In this case, the refractive indices of the first lens 110, third lens 130, and fifth lens 150 can be less than the refractive indices of the second lens 120 and fourth lens 140.

[0111] The Abbe numbers of the first lens 110, the third lens 130, and the fifth lens 150 can be equal to each other, and the Abbe numbers of the second lens 120 and the fourth lens 140 can be equal to each other. In this case, the Abbe numbers of the first lens 110, the third lens 130, and the fifth lens 150 can be greater than the Abbe numbers of the second lens 120 and the fourth lens 140.

[0112] Table 2 relates to the characteristics of the optical system 1000 according to the embodiments. In Table 2, the total track length (TTL) is the distance (mm) along the optical axis from the vertex of the object-side surface (first surface S1) of the first lens 110 to the upper surface of the image sensor 300, and the effective focal length (EFL) represents the focal length (mm) of the optical system 1000 including the first to fifth lenses 110, 120, 130, 140, and 150. Furthermore, the back focal length (BFL) can represent the distance (mm) along the optical axis from the image-side surface (tenth surface S10) of the fifth lens 150 to the image sensor 300, and each of f1 to f5 can represent the focal length (mm) of each of the first to fifth lenses 110, 120, 130, 140, and 150. Referring to Table 2, the fifth lens 150 can have the largest focal length value among the first to fifth lenses 110, 120, 130, 140, and 150.

[0113] In the optical system 1000 according to the embodiment, the values ​​of the aspherical coefficients of each lens are shown in Table 3.

[0114] [Table 3]

[0115]

[0116]

[0117]

[0118] Table 4 shows the values ​​of Formulas 1 to 10 applied to an optical system according to an embodiment of the present invention.

[0119] [Table 4]

[0120]

[0121]

[0122] Table 4 shows the values ​​for the optical system 1000 described above. Referring to Table 4, it can be seen that the optical system 1000 according to the embodiment satisfies at least one of equations 1 to 9. In detail, it can be seen that the optical system 1000 satisfies all of equations 1 to 10. Therefore, the optical system 1000 according to the embodiment can have the following characteristics: Figure 2 The aberration characteristics are shown. In detail, Figure 2 This is a graph showing the aberration diagram of the optical system 1000 according to an embodiment, where spherical aberration, astigmatism curvature, and distortion are measured from left to right. Figure 2 In the diagram, the X-axis represents focal length (mm) and distortion (%), and the Y-axis represents the height of the image sensor. Furthermore, the spherical aberration graph is a graph of light in the wavelength bands of 435nm, 486nm, 546nm, 587nm, and 656.3nm, and the astigmatism and distortion graph is a graph of light in the wavelength band of 546nm. The optical system 1000 according to an embodiment of the present invention can have improved optical characteristics. Specifically, in the optical system 1000, the effective aperture of the fifth lens 150 closest to the image sensor 300 can be larger than the effective aperture of the first lens 110 closest to the object side, thereby improving optical characteristics. In particular, since the effective aperture of the fifth lens 150 is the largest among the multiple lenses, improved optical characteristics can be obtained when designing zoom lenses with image sensors 300 of various sizes (e.g., from small to large). Furthermore, improved optical characteristics can be obtained when the optical system 1000 is used as a telephoto lens.

[0123] An optical system can have improved optical characteristics by having a relatively small back focal length (BFL) value. Specifically, because the distance BFL between the image sensor 300 and the fifth lens 150 has a relatively small value, reflection of light incident on the optical system 1000 at the structure between the fifth lens 150 and the image sensor 300 can be prevented or minimized. Therefore, by easily correcting the CRA value (e.g., the angle of light passing through the fifth lens 150 and incident on the image sensor 300), the optical system 1000 according to the embodiment can have improved optical characteristics.

[0124] The features, structures, effects, etc., described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc., shown in each embodiment can be combined or modified by those skilled in the art for other embodiments. Therefore, anything related to such combinations and modifications should be interpreted as being included within the scope of the present invention. Additionally, although embodiments have been described above, these are merely examples and do not limit the present invention; those skilled in the art have illustrated the above without departing from the basic characteristics of these embodiments. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be implemented by modification. And differences related to such modifications and applications should be interpreted as being included within the scope of the present invention as defined in the appended claims.

Claims

1. An optical system, comprising: Optical path changing components and multiple lenses are sequentially arranged along the optical axis from the object side towards the image side. The plurality of lenses comprises a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis in a direction from the object side toward the image side. The optical path changing component includes a mirror or a prism. The distance between the plurality of lenses remains unchanged. Each of the first to fifth lenses includes an object-side surface and an image-side surface. The first lens has positive refractive power. The object-side surface of the first lens has a convex shape along the optical axis. The image-side surface of the second lens has a convex shape along the optical axis. The image-side surface of the third lens has a concave shape along the optical axis. Among the first to the fifth lenses, the fifth lens, which is closest to the image side, has an effective aperture larger than that of the first to the fourth lenses. The second lens has negative refractive power. The third lens has negative refractive power. The fourth lens has positive refractive power. The fifth lens has positive refractive power. The image-side surface of the fifth lens has a concave shape along the optical axis. The center thickness of the first lens is CT1. The center thickness of the fifth lens is CT5. Wherein, the following equation is satisfied: [Mode] 。 2. The optical system according to claim 1, in, The effective area of ​​the image sensor is half the length of its diagonal direction, which is ImgH. Wherein, the distance from the image-side surface of the fifth lens to the image sensor along the optical axis is the back focal length BFL. Wherein, the following equation is satisfied: [Mode] 。 3. The optical system according to claim 1 or 2, in, The image-side surface of the first lens has a convex shape along the optical axis. The object-side surface of the fifth lens has a convex shape along the optical axis. The effective aperture size of each of the first lens and the fifth lens satisfies the following equation: [Formula 1] ， ， In Equation 1, CA11 represents the effective aperture size of the object-side surface of the first lens, CA12 represents the effective aperture size of the image-side surface of the first lens, CA51 is the effective aperture size of the object-side surface of the fifth lens, and CA52 represents the effective aperture size of the image-side surface of the fifth lens.

4. The optical system according to claim 3, in, The object-side surface of the third lens has a convex shape on the optical axis.

5. The optical system according to claim 2, in, Satisfy the following equation 2: [Equation 2] ， In Equation 2, CA is the size of the effective aperture of the object-side or image-side surface of a lens selected from the first lens to the fifth lens.

6. The optical system according to claim 5, in, The distance from the object-side surface of the first lens to the image sensor along the optical axis is the total track length (TTL), and Among them, the following equation 3 is satisfied: [Formula 3] 。 7. The optical system according to claim 1 or 2, in, The effective focal length (EFL) of the optical system is greater than 10 mm.

8. The optical system according to claim 1 or 2, in, The optical system has an F-number of less than 3.

8.

9. The optical system according to claim 1 or 2, in, The optical system has a principal ray incident angle (CRA) of less than 40°.

10. The optical system according to claim 1 or 2, in, The second lens has negative refractive power. The object-side surface of the second lens has a concave shape along the optical axis, and The image-side surface of the first lens has a convex shape on the optical axis.

11. The optical system according to claim 1 or 2, in, The object-side surface of the third lens has a convex shape along the optical axis. The object-side surface of the fourth lens has a convex shape along the optical axis, and The object-side surface of the fifth lens has a convex shape on the optical axis.

12. The optical system according to claim 1 or 2, in, The object-side surface of the third lens has an inflection point.

13. An optical system comprising: Optical path changing components and multiple lenses arranged sequentially from the object side to the image side, and Image sensor, The plurality of lenses comprises a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis in a direction from the object side toward the image side. The optical path changing component includes a mirror or a prism. The distance between the plurality of lenses remains unchanged. Each of the first to fifth lenses includes an object-side surface and an image-side surface. The first lens has positive refractive power. The object-side surface of the first lens has a convex shape along the optical axis. The image-side surface of the second lens has a convex shape along the optical axis. The image-side surface of the third lens has a concave shape along the optical axis. The second lens has negative refractive power. The third lens has negative refractive power. The fourth lens has positive refractive power. The fifth lens has positive refractive power. The image-side surface of the fifth lens has a concave shape along the optical axis. In the direction of the optical axis, the distance from the image-side surface of the fifth lens, which is closest to the image sensor among the plurality of lenses, to the image sensor is defined as the back focal length of the BFL. Wherein, half the diagonal length of the effective area of ​​the image sensor is ImgH. The center thickness of the first lens is CT1. The center thickness of the fifth lens is CT5, and Among them, the following equation 4 is satisfied: [Formula 4] ， 。 14. The optical system according to claim 13, in, The object-side surface of the third lens has a convex shape along the optical axis. Wherein, the effective aperture size of the object-side surface or image-side surface of one of the lenses selected from the first lens to the fifth lens is CA, and Wherein, the following equation is satisfied: [Mode] 。 15. The optical system according to claim 13 or 14, in, The image-side surface of the first lens has a convex shape along the optical axis. The object-side surface of the fifth lens has a convex shape along the optical axis. Wherein, the distance from the object-side surface of the first lens to the image sensor along the optical axis is the total track length (TTL), and Wherein, the following equation is satisfied: [Mode]: 。

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