KR20240071814A - Optical system and camera module - Google Patents

Abstract

The optical system disclosed in the embodiment of the invention is arranged along the optical axis from the object side to the sensor side and includes first to third lens groups each including at least one lens, the first lens group and the third lens. group has negative power, the second lens group has positive power, the position of the first lens group is fixed, and the second and third lens groups are smaller than the number of lenses of the first lens group. The optical system has a lens and is movable in the direction of the optical axis, and has the first to third lens groups. The optical system has magnification according to at least three modes according to the movement of each of the second lens group and the third lens group, and the optical system has magnification according to at least three modes. At least one of the second and third lens groups has a lens with the thickest center thickness, and the optical axis distance between the surface closest to the object side among the lenses of the first lens group and the image surface of the image sensor is TTL, and is the highest among the operation modes. When operating at magnification, the entrance pupil diameter of the optical system is EPD3, and the equation: 2 < TTL / EPD3 < 7 can be satisfied.

Description

Optical system and camera module {OPTICAL SYSTEM AND CAMERA MODULE}

The embodiment relates to an optical system for improved optical performance and a camera module including the same.

Camera modules perform the function of photographing objects and saving them as images or videos, and are installed in various applications. In particular, the camera module is manufactured in an ultra-small size and is applied to not only portable devices such as smartphones, tablet PCs, and laptops, but also drones and vehicles, providing various functions. For example, the optical system of the camera module may include an imaging lens that forms an image, and an image sensor that converts the formed image into an electrical signal. At this time, the camera module can perform an autofocus (AF) function that automatically adjusts the distance between the image sensor and the imaging lens to align the focal length of the lens, and can focus on distant objects through a zoom lens. The zooming function of zoom up or zoom out can be performed by increasing or decreasing the magnification of the camera. In addition, the camera module adopts image stabilization (IS) technology to correct or prevent image shake caused by camera movement due to an unstable fixation device or the user's movement.

The most important element for a camera module to obtain an image is the imaging lens that forms the image. Recently, interest in high resolution has been increasing, and research is being conducted on optical systems including multiple lenses to realize this. For example, to realize high resolution, research is being conducted using a plurality of imaging lenses with positive (+) or negative (-) refractive power. However, when a plurality of lenses are included, there is a problem in that it is difficult to obtain excellent optical and aberration characteristics. In addition, when a plurality of lenses are included, the overall length, height, etc. may increase depending on the thickness, spacing, and size of the plurality of lenses, which increases the overall size of the module including the plurality of lenses. There is.

The size of image sensors is increasing to realize high-resolution and high-quality images. However, as the size of the image sensor increases, the total track length (TTL) of the optical system including a plurality of lenses also increases, which causes the thickness of cameras and mobile terminals including the optical system to also increase.

When the optical system includes a plurality of lenses, zoom, autofocus (AF) functions, etc. can be performed by controlling the position of at least one lens or a lens group including at least one lens. However, when the lens or the lens group performs the above function, the amount of movement of the lens or the lens group may increase exponentially. Accordingly, the optical system may require a lot of energy to move the lens or the lens group, and has a problem of requiring a large volume in consideration of the amount of movement. Additionally, when the lens or the lens group is moved, there is a problem in that the aberration characteristics are deteriorated due to the movement. Accordingly, there is a problem that optical characteristics deteriorate at a certain magnification when performing zoom and autofocus (AF) functions. Therefore, a new optical system that can solve the above-mentioned problems is required.

The embodiment seeks to provide an optical system with improved optical characteristics. The embodiment seeks to provide an optical system and a camera module capable of taking pictures at various magnifications. The embodiment seeks to provide an optical system and a camera module with improved aberration characteristics at various magnifications. The embodiment seeks to provide an optical system and camera module that can be implemented in a small and compact manner.

An optical system according to an embodiment of the invention is arranged along an optical axis from the object side to the sensor side and includes first to third lens groups each including at least one lens, the first lens group and the third lens. group has negative power, the second lens group has positive power, the position of the first lens group is fixed, and the second and third lens groups are smaller than the number of lenses of the first lens group. The optical system has a lens and is movable in the direction of the optical axis, and has the first to third lens groups. The optical system has magnification according to at least three modes according to the movement of each of the second lens group and the third lens group, and the optical system has magnification according to at least three modes. At least one of the second and third lens groups has a lens with the thickest center thickness, and the optical axis distance between the surface closest to the object side among the lenses of the first lens group and the image surface of the image sensor is TTL, and is the highest among the operation modes. When operating at magnification, the entrance pupil diameter of the optical system is EPD3, and the equation: 2 < TTL / EPD3 < 7 can be satisfied.

According to an embodiment of the invention, the optical axis spacing between the image sensor and the lens closest to the image sensor in the third lens group may vary depending on the operation mode.

According to an embodiment of the invention, the optical axis distance between the object-side surface of the lens closest to the object in the first lens group and the sensor-side surface of the lens closest to the image sensor in the third lens group is determined in the operation mode. It may vary depending on the

According to an embodiment of the invention, the operation mode includes a wide mode, the wide mode is Mode1, the optical axis spacing between the first and second lens groups in the wide mode is DG12, and the second and third lens groups The optical axis spacing between them is DG23, and the equation: 1< Mode1 (DG12 / DG23) < 5 can be satisfied.

According to an embodiment of the invention, the operation mode includes a tele mode, the tele mode is Mode3, the optical axis spacing between the first and second lens groups in the tele mode is DG12, and the second and third lens groups The optical axis spacing between them is DG23, and the equation: 0 < Mode3 (DG12 / DG23) < 0.7 can be satisfied.

According to an embodiment of the invention, the maximum spacing between adjacent lenses according to the operation mode is Mode_CG_Max, and the minimum spacing between adjacent lenses according to the operation mode is Mode_CG_Min, using the equation: 2 < Mode_CG_Max / Mode_CG_Min < 8 You can be satisfied.

According to an embodiment of the invention, the number of lenses in the first lens group is three, and the absolute value of the focal lengths of the first and third lens groups may be greater than the focal length of the second lens group.

According to an embodiment of the invention, the optical system has a wide mode with a first effective focal length (EFL1), a middle mode with a second effective focal length (EFL2), and a tele mode with a third effective focal length (EFL3). It includes and can satisfy the equation: EFL1 < ELF2 < EFL3.

According to an embodiment of the invention, the angle of view in the wide mode is FOV1, the angle of view in the middle mode is FOV2, and the angle of view in the tele mode is FOV3, and the equation is: 8 degrees < FOV3 < FOV2 < FOV1 < 45 can be satisfied.

According to an embodiment of the invention, the second lens group may include an object-side lens having an aspherical surface made of glass and having both sides convex, and a sensor-side lens having an aspherical surface made of plastic.

An optical system according to an embodiment of the invention includes a first lens group having first to third lenses; a second lens group having fourth and fifth lenses; It includes a third lens group having sixth and seventh lenses, wherein the first lens group, the second lens group, and the third lens group are arranged in the optical axis direction from the object side to the sensor side, The first lens has a positive refractive power and a convex shape on both object sides, the third lens has a negative refractive power and a concave shape on both sides, and the fourth lens has a positive refractive power and a convex shape on both sides. The seventh lens has a negative refractive power, the second lens group and the third lens group are moved in the optical axis direction, and the optical axis spacing between the seventh lens and the image sensor depends on the operation mode. It can be variable.

According to an embodiment of the invention, the first lens group has negative refractive power, the first lens has a meniscus shape convex toward the object, and the second lens has a meniscus shape convex toward the sensor. and the second and fifth lenses may have negative refractive power.

According to an embodiment of the invention, the fourth lens and the seventh lens may have a refractive index of less than 1.6.

According to an embodiment of the invention, the fourth lens may be made of glass and may be an aspherical lens, and the first, second, 3, 5, 6, and 7 lenses may be made of plastic and may be aspherical lenses.

According to an embodiment of the invention, the maximum length of the first lens in the first direction orthogonal to the optical axis may be different from the maximum length in the second direction.

According to an embodiment of the invention, the maximum length in the first and second directions of the first lens is the largest among the lenses, the difference between the center thickness and the edge thickness of the fifth lens is 0.9 or more, and the center of the sixth lens is The difference between the thickness and the edge thickness can be more than 0.9.

According to an embodiment of the invention, the optical axis spacing between the first and second lens groups and the optical axis spacing between the second and third lens groups may be at least 0.2 mm or more and at most 8 mm or less.

According to an embodiment of the invention, Vd4 is the Abbe number of the fourth lens, Vd5 is the Abbe number of the fifth lens, Vd6 is the Abbe number of the sixth lens, and Vd7 is the Abbe number of the seventh lens, equation: 20 < |Vd4 - Vd5| < 70 and 15 < |Vd7 - Vd6| < 60 can be satisfied.

According to an embodiment of the invention, the optical axis distance from the center of the object-side surface of the fourth lens to the center of the sensor-side surface of the fifth lens is DG2, and the distance between the object side of the first lens and the image sensor is DG2. The optical axis distance is TTL, and the equation: 3 < TTL/DG2 < 10 can be satisfied.

A camera module according to an embodiment of the invention includes an optical system and a driving member, wherein the optical system includes the optical system disclosed above, and the driving member determines each position of the second and third lens groups along the optical axis. It can be driven in one direction.

The optical system and camera module according to the embodiment have various magnifications and can have excellent optical characteristics when various magnifications are provided. In detail, the embodiment can have various magnifications by controlling the moving distance of each moving lens group and can provide an autofocus (AF) function for the subject. The optical system and camera module according to the embodiment may correct aberration characteristics of a plurality of lens groups or complement each other for aberration characteristics that change due to movement. Accordingly, the optical system according to the embodiment can minimize or prevent changes in chromatic aberration and changes in aberration characteristics that occur when magnification changes.

The optical system and camera module according to the embodiment can control the effective focal length (EFL) by moving only some lens groups among a plurality of lens groups and minimize the moving distance of the moving lens groups. Accordingly, the optical system can reduce the moving distance of the lens group that moves according to the change in operation mode, and minimize power consumption required when moving the lens group. In the optical system, at least one lens included in the fixed group and the moving group may have a non-circular shape. Accordingly, the height of the optical system can be reduced while maintaining optical performance, and a space in which lens groups disposed between a plurality of lens groups can be structurally arranged can be secured.

The optical system and camera module according to the embodiment may adjust the magnification to enlarge or reduce the object by moving a lens group other than the first lens group adjacent to the object among the plurality of lens groups. Accordingly, the optical system can have a constant TTL value even when the lens group moves according to magnification changes to have multiple focal lengths, and can be applied to a camera module for linear zoom. Accordingly, the optical system and the camera module including it can be provided in a slimmer structure.

Figure 1 is a configuration diagram of an optical system and a camera module having the same according to an embodiment of the invention.
FIG. 2 is a modified example of the first mode of the optical system of FIG. 1.
Figure 3 is an example of a change to the third mode in the optical system of Figures 1 and 2.
FIG. 4 shows a configuration including a reflection mirror in the optical system of FIG. 1.
Figure 5 is a table of lens data of an optical system according to an embodiment of the invention.
Figure 6 is a graph showing relative illumination according to position in wide, middle, and tele modes according to an embodiment of the invention.
Figure 7 is a graph of diffraction MTF (Diffraction MTF) in the first mode (wide mode) optical system according to an embodiment of the invention.
Figure 8 is a graph of diffraction MTF in a second mode (Middle Mode) optical system according to an embodiment of the invention.
Figure 9 is a graph of diffraction MTF (Diffraction MTF) in a third mode (Tele Mode) optical system according to an embodiment of the invention.
Figure 10 is a graph showing aberration characteristics in a first mode optical system according to an embodiment of the invention.
Figure 11 is a graph showing aberration characteristics in a second mode optical system according to an embodiment of the invention.
Figure 12 is a graph showing aberration characteristics in a third mode optical system according to an embodiment of the invention.
Figure 13 is a diagram showing a camera module according to an embodiment of the invention applied to a mobile terminal.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical idea of the present invention is not limited to some of the described embodiments, but may be implemented in various different forms, and as long as it is within the scope of the technical idea of the present invention, one or more of the components may be optionally used between the embodiments. It can be used by combining and replacing. In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless explicitly specifically defined and described, are generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as meaning, and the meaning of commonly used terms, such as terms defined in a dictionary, can be interpreted by considering the contextual meaning of the related technology. The terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In this specification, the singular may also include the plural unless specifically stated in the phrase, and when described as "at least one (or more than one) of A and B and C", it is combined with A, B, and C. It can contain one or more of all possible combinations. Additionally, when describing the components of an embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and are not limited to the essence, order, or order of the component. And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to that other component, but also is connected to that component. It may also include cases where other components are 'connected', 'coupled', or 'connected' by another component between them.

When described in the specification as being formed or disposed "above" or "below" each component, "above" or "below" refers not only to cases in which two components are in direct contact with each other, but also to one This also includes cases where another component described above is formed or placed between two components. In addition, when expressed as "top (above) or bottom (bottom)", it can include not only the upward direction but also the downward direction based on one component.

In the specification, saying that the surface of the lens is convex may mean that the surface of the lens in the area corresponding to the optical axis has a convex shape based on the optical axis, and that the surface of the lens is concave means that the surface of the lens in the area corresponding to the optical axis has a concave shape. It may mean having a . In addition, “object side” may refer to the side of the lens facing the object side based on the optical axis, and “sensor side” may refer to the side of the lens facing the imaging surface (image sensor) based on the optical axis. . Additionally, the central thickness of the lens may mean the thickness of the lens in the optical axis direction of the lens. Additionally, the vertical direction may mean a direction perpendicular to the optical axis, and the end of the lens or lens surface may mean the end of the effective area of the lens through which incident light passes. Additionally, the size of the effective diameter of the lens surface may have a measurement error of up to ±0.4mm depending on the measurement method.

Figure 1 is a configuration diagram of an optical system according to an embodiment of the invention, Figure 2 is an example of a change from the first mode to the second mode of the optical system of Figure 1, and Figure 3 is a change from the optical system of Figures 1 and 2 to the third mode. This is a modified example of, Figure 4 is a configuration having a reflection mirror in the optical system of Figure 1, Figure 5 is a table of lens data of the optical system according to an embodiment of the invention, and Figure 6 is a wide camera module according to an embodiment of the invention. It is a graph showing the relative illuminance according to the positions of the , middle, and tele modes, and FIG. 7 is a graph of the diffraction MTF (Diffraction MTF) in the optical system of the first mode (Wide Mode) according to an embodiment of the invention. 9 is a graph of the diffraction MTF in the optical system of the second mode (Middle mode) according to an embodiment of the invention, and FIG. 9 is a graph of the diffraction MTF in the optical system of the third mode (Tele mode) according to an embodiment of the invention. 10 is a graph showing aberration characteristics in a first mode optical system according to an embodiment of the invention, FIG. 11 is a graph showing aberration characteristics in a second mode optical system according to an embodiment of the invention, and FIG. 12 is an embodiment of the invention. This is a graph showing the aberration characteristics in the third mode optical system according to .

Referring to FIGS. 1 to 12 , the optical system 1000 according to the embodiment may include a plurality of lens groups G1, G2, and G3. In detail, the plurality of lens groups G1, G2, and G3 may have at least two lens groups movable in the direction of the optical axis OA and at least one lens group whose position is fixed. The plurality of lens groups G1, G2, and G3 may include a fixed lens group on the object side and a plurality of movable lens groups on the sensor side.

The plurality of moving lens groups may include an object-side lens group and a sensor-side lens group. The lens group fixed on the object side may be defined as a first lens group (G1), the object-side movable lens group may be defined as a second lens group (G2), and the sensor-side movable lens group may be defined as a second lens group (G2). It can be defined as 3 lens group (G3). The second lens group (G2) may be disposed between the first lens group (G1) and the third lens group (G3).

The first lens group (G1) collects incident light, the second lens group (G2) changes the zoom factor (focal length), and the third lens group (G3) uses the image sensor 300. The focus position on the image surface can be adjusted.

The optical system 1000 may include a first lens group (G1), a second lens group (G2), and a third lens group (G3) sequentially arranged along the optical axis (OA) from the object side to the sensor. there is. The optical system 1000 may include an image sensor 300 on the sensor side of the third lens group G3. The first lens group G1 may include lenses closest to the object side, and the third lens group G3 may include lenses closest to the sensor side. Each of the first to third lens groups G1, G2, and G3 may have positive (+) or negative (-) refractive power. For example, the lens group with positive refractive power may be at least two lens groups, and the lens group with negative refractive power may be a single lens group.

The first lens group G1 may have a refractive power opposite to that of the second lens group G2. For example, the first lens group G1 may have negative (-) refractive power, and the second lens group G2 may have positive (+) refractive power. The second lens group G2 may have a refractive power opposite to that of the third lens group G3. For example, the second lens group G2 may have positive (+) refractive power, and the third lens group (G3) may have negative (-) refractive power. The third lens group G3 may have negative (-) refractive power.

The absolute value of the power of the first lens group (G1) may be greater than the absolute value of the power of the second and third lens groups (G2 and G3). For example, the absolute value of the power of the first lens group (G1) may be more than twice the absolute value of the power of the second lens group (G2). Accordingly, the first lens group G1 can disperse incident light. The first and third lens groups G1 and G3 may have negative power, and the second lens group G2 may have positive power.

The number of lenses of the first lens group (G1) may be greater than the number of lenses of the second lens group (G2). For example, the number of lenses of the third lens group (G3) may be smaller than the number of lenses of the first lens group (G1). The number of lenses of the first lens group (G1) may include at least three lenses to control incident light quantity, refractive power, and chromatic aberration. The second and third lens groups G2 and G3 may include at least two lenses. For example, the optical system may further include at least one lens fixed between the third lens group G3 and the image sensor 300.

The focal length of the second lens group G2 may have a sign opposite to that of the first lens group G1. The focal length of the second lens group G2 may have a positive (+) sign, and the focal length of the first lens group G1 may have a negative (-) sign. The refractive power is the reciprocal of the focal length.

As the second and third lens groups G2 and G3 have opposite refractive powers as described above, the focal length of the second lens group G2 is opposite to that of the third lens group G3. It can have signs (+, -). For example, the focal length of the second lens group G2 may have a positive (+) sign, and the focal length of the third lens group G3 may have a negative (-) sign.

The absolute value of the focal length of each of the first to third lens groups (G1, G2, and G3) is the first lens group (G1), the third lens group (G3), and the second lens group (G2). It can be smaller in order.

Since the first lens group (G1) is fixed in position and the second lens group (G2) and the third lens group (G3) are movable in the direction of the optical axis (OA), the optical system can perform various functions by moving the lens groups. Magnification can be provided.

Hereinafter, the first to third lens groups G1, G2, and G3 will be described in more detail. The first lens group G1 may include at least two lenses having opposite refractive powers. For example, the first lens group G1 may include three lenses. In the first lens group G1, the number of lenses with positive refractive power may be greater than the number of lenses with negative refractive power.

A plurality of lenses included in the first lens group G1 may have set intervals. In detail, the center spacing between the plurality of lenses included in the first lens group G1 may be a fixed spacing according to an operation mode that will be described later. For example, the center distance (CG1) between the first lens 101 and the second lens 102 and the center distance (CG2) between the second lens 102 and the third lens 103 are The interval can be constant without changing depending on the operation mode. Here, the center spacing (CG) between the lenses may mean the optical axis spacing between adjacent lenses.

The second lens group G2 may include a plurality of lenses. In detail, the second lens group G2 may include three or less lenses having refractive power. The number of lenses included in the second lens group G2 may be one or more less than the number of lenses included in the first lens group G1. For example, the second lens group G2 may include two lenses having the same refractive power. A plurality of lenses included in the second lens group G2 may have set intervals. In detail, the center spacing (CG) between the plurality of lenses included in the second lens group (G2) may be a fixed spacing according to an operation mode that will be described later. For example, the center distance CG4 between the fourth lens 104 and the fifth lens 105 may have a constant distance without changing depending on the operation mode.

The third lens group G3 may include a plurality of lenses. In detail, the third lens group G3 may include two or more lenses having refractive power. Lenses included in the third lens group G3 may have negative refractive power. The number of lenses included in the third lens group G3 may be the same as the number of lenses included in the second lens group G2. For example, the third lens group G3 may include two lenses.

A plurality of lenses included in the third lens group G3 may have set intervals. In detail, the center spacing between the plurality of lenses included in the third lens group G3 may be constant without changing even if the operation mode, which will be described later, changes. For example, the center distance CG6 between the sixth lens 106 and the seventh lens 107 may be constant without changing depending on the operation mode. The distance DG4 between the last lens included in the third lens group G3 and the optical filter 500 may vary depending on the operation mode. Additionally, the distance between the last lens and the image sensor 300 is BFL and may vary depending on the operation mode.

The optical system 1000 may include a plurality of lenses 100 included in the lens groups G1, G2, and G3, for example, first to seventh lenses 101, 102, 103, 104, 105, 106, and 107. The first lens group G1 may include the first to third lenses 101, 102, and 103, and the second lens group G2 may include the fourth and fifth lenses 104 and 105. Additionally, the third lens group G3 may include the sixth to seventh lenses 106 and 107. The first to seventh lenses 101, 102, 103, 104, 105, 106, and 107 and the image sensor 300 may be sequentially arranged along the optical axis OA of the optical system 1000.

The first lens group G1 may include at least one internal lens whose length in the first direction orthogonal to the optical axis is different from that in the second direction, and may include, for example, at least one non-circular lens. The second lens group G2 may include at least one internal lens whose length in the first direction and the length in the second direction perpendicular to the optical axis are different from each other, and may include, for example, at least one non-circular lens. The third lens group G3 may include at least one internal lens whose length in the first direction and the length in the second direction perpendicular to the optical axis are different from each other, and may include, for example, at least one non-circular lens. For example, the first lens 101, which has the largest diameter among the lenses, may have a length in the first direction and a length in the second direction that are different from each other. Additionally, the length of the fourth lens 104 in the first direction may be different from that in the second direction.

The optical system 1000 according to the embodiment may have improved assembly properties and a mechanically stable form due to the non-circular lens(s). Additionally, the optical system 1000 can significantly reduce the moving distance of the moving lens group and provide various magnifications.

Each of the plurality of lenses 100 may include an effective area and an uneffective area. The effective area is an area of an effective diameter and may be an area through which light incident on each of the first to seventh lenses 101, 102, 103, 104, 105, 106, and 107 passes. The effective area may be an area where incident light is refracted to implement optical characteristics. The non-effective area may be arranged around the effective area. The non-effective area may be an area where the light is not incident. That is, the non-effective area may be an area unrelated to the optical characteristics. Additionally, the non-effective area may be an area fixed to a barrel (not shown) that accommodates the lens.

The image sensor 300 can detect light. The image sensor 300 may detect light that sequentially passes through the plurality of lenses 100, for example, the first to seventh lenses 101, 102, 103, 104, 105, 106, and 107. The image sensor 300 may include a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

The optical system 1000 may further include an optical filter 500. The optical filter 500 may be disposed between the plurality of lenses 100 and the image sensor 300. The optical filter 500 may be disposed between the image sensor 300 and the fourth lens group G4. For example, the optical filter 500 may be disposed between the image sensor 300 and the seventh lens 107 of the fourth lens group G4.

The optical filter 500 may include at least one of an infrared filter and a cover glass. The optical filter 500 may pass light in a set wavelength band and filter light in a different wavelength band. When the optical filter 500 includes an infrared filter, radiant heat emitted from external light can be blocked from being transmitted to the image sensor 300. The optical filter 500 can transmit visible light and reflect infrared rays.

The optical system 1000 may include an aperture (not shown). The aperture can control the amount of light incident on the optical system 1000. The aperture may be located around the object-side surface of the first lens 101, or may be placed between two lenses selected from the first to seventh lenses 101, 102, 103, 104, 105, 106, and 107. For example, the aperture may be disposed around the third lens 103 and the fourth lens 104. The aperture may be disposed around the sensor-side surface of the third lens 103 or around the object-side surface of the fourth lens 104. Alternatively, at least one lens among the first to seventh lenses 101, 102, 103, 104, 105, 106, and 107 may function as an aperture. For example, the outer portion of the object side or sensor side of one lens selected from among the first to seventh lenses 101, 102, 103, 104, 105, 106, and 107 may function as an aperture to adjust the amount of light. For example, at least one lens surface of the sensor side of the third lens 103 and the object side of the fourth lens 104 may function as an aperture.

The object-side surface and the sensor-side surface of the first to seventh lenses (101, 102, 103, 104, 105, 106, and 107) may be aspherical. At least one of the first to seventh lenses 101, 102, 103, 104, 105, 106, and 107 may be made of a glass mold material. For example, at least one of the third and fourth lenses 103 and 104 may be a glass mold lens, and in detail, the fourth lens 104 may be made of a glass mold material. The first, 2, 3, 5, 6, 7, and 8 lenses (101, 102, 103, 105, 106, and 107) may be made of plastic. Since the lens of the glass mold is disposed within the lenses 100, TTL can be reduced.

The optical system 1000 may further include an optical path changing member 400 as shown in FIG. 4 . The optical path change member 400 may reflect light incident from the outside and change the light path from the second path OA2 to the first path 0A1. The optical path changing member 400 may include a reflector or prism. For example, the light path changing member 400 may include a right-angled prism. When the optical path changing member 400 includes a right-angled prism, the optical path changing member 400 can change the first path (OA1) of light by reflecting the second path (OA2) of the incident light at an angle of 90 degrees. there is. The first path OA1 may be in the direction of the optical axis of the optical system. The optical path changing member 400 may be disposed closer to the object than the plurality of lenses 100 . That is, when the optical system 1000 includes the optical path changing member 400, the optical path changing member 300, the first lens 101, the second lens 102, and the optical path changing member 300 in the direction from the object side to the sensor. The 3rd lens 103, the 4th lens 104, the 5th lens 105, the 6th lens 106, the 7th lens 107, the optical filter 500, and the image sensor 300 can be arranged in this order. there is.

The optical path changing member 400 can change the path of light incident from the outside in a set direction. For example, the optical path changing member 400 directs the second path OA2 of the light incident on the optical path changing member 400 in the first direction to the second path OA2, which is the arrangement direction of the plurality of lenses 100. The direction can be changed to the first path (OA1). When the optical system 1000 includes the optical path changing member 400, the optical system can be applied to a folded camera, thereby reducing the thickness of the camera. In detail, when the optical system 1000 includes the optical path changing member 400, the light incident in the direction perpendicular to the surface of the device to which the optical system 1000 is applied (the first direction) is connected to the surface of the device. It can be changed to a parallel direction (second direction). Accordingly, the optical system 1000 including a plurality of lenses 100 can have a thinner thickness within the device, thereby reducing the height of the device.

When the optical system 1000 does not include the optical path change member, the plurality of lenses 100 may be disposed within the device extending in a direction perpendicular to the surface of the device (first direction). . Accordingly, the optical system 1000 including the plurality of lenses 100 has a high height in the direction perpendicular to the surface of the device (first direction), and as a result, the optical system 1000 and the device including the same It may be difficult to form a thin thickness. However, when the optical system 1000 includes the optical path changing member 400, the plurality of lenses 100 may be arranged to extend in a direction (second direction) parallel to the surface of the device. . That is, the optical system 1000 is arranged so that the optical axis (OA) is parallel to the surface of the device and can be applied to a folded camera. Accordingly, the optical system 1000 including the plurality of lenses 100 may have a low height in a direction perpendicular to the surface of the device. Accordingly, the camera including the optical system 1000 can have a thin thickness within the device, and the thickness of the device can also be reduced.

As another example, the optical path change member may be disposed between two lenses of the plurality of lenses 100 or between the image sensor 300 and the last lens adjacent to the image sensor 300. As another example, a plurality of optical path change members may be provided. In detail, a plurality of optical path change members may be disposed between the object and the image sensor 300. For example, the plurality of optical path changing members may include a first optical path changing member disposed closer to the object side than the plurality of lenses 100 and a second optical path changing member disposed between the last lens and the image sensor 300. 2 May include an optical path changing member. Accordingly, the optical system 1000 can have various shapes and heights depending on the camera to which it is applied, and can have improved optical performance.

1 to 3, the first lens group (G1) includes first to third lenses (101, 102, 103), and the second lens group (G2) includes fourth and fifth lenses (104, 105). The third lens group G3 may include sixth to seventh lenses 106 and 107.

The first lens 101 may be placed closest to the object among the plurality of lenses 100, and the seventh lens 107 may be placed closest to the image sensor 300. there is.

The first lens 101 may have positive (+) refractive power at the optical axis OA. The first lens 101 may include a plastic or glass material, for example, a plastic material. The first lens 101 may include a first surface (S1) defined as an object-side surface and a second surface (S2) defined as a sensor-side surface. The first surface S1 may have a convex shape with respect to the optical axis OA, and the second surface S2 may have a concave shape with respect to the optical axis OA. That is, the first lens 101 may have a meniscus shape that is convex from the optical axis OA toward the object. Alternatively, the second surface S2 of the first lens 101 may have a convex shape at the optical axis OA. At least one of the first surface (S1) and the second surface (S2) may be an aspherical surface. For example, both the first surface (S1) and the second surface (S2) may be aspherical.

The center thickness (CT1) of the first lens 101 is the thickness at the optical axis and may be thicker than the edge thickness (ET1). The edge thickness ET1 is the optical axis distance between the edge of the object-side surface and the edge of the sensor-side surface of the first lens 101. Accordingly, the first lens 101 can improve optical aberration or control incident light. The first surface (S1) and the second surface (S2) may be provided without a critical point from the optical axis to the end of the effective area.

The second lens 102 may have positive (+) or negative (-) refractive power at the optical axis OA, for example, positive refractive power. The second lens 102 may include a plastic or glass material, for example, a plastic material. The second lens 102 may include a third surface S3 defined as the object side surface and a fourth surface S4 defined as the sensor side surface. The third surface S3 may have a concave shape with respect to the optical axis OA, and the fourth surface S4 may have a convex shape with respect to the optical axis OA. The second lens 102 may have a meniscus shape that is convex from the optical axis OA toward the sensor. Alternatively, the third surface S3 may have a convex shape at the optical axis OA, and the fourth surface S4 may have a convex shape. That is, the second lens 102 may have a shape in which both sides are convex at the optical axis OA. Alternatively, the third surface S3 may have a concave shape along the optical axis OA, and the fourth surface S4 may have a concave shape along the optical axis OA. Alternatively, the third surface S3 may have a convex shape with respect to the optical axis OA, and the fourth surface S4 may have a concave shape with respect to the optical axis OA. At least one of the third surface S3 and the fourth surface S4 may be an aspherical surface. For example, both the third surface S3 and the fourth surface S4 may be aspherical. The third surface S3 and the fourth surface S4 may be provided without a critical point from the optical axis to the end of the effective area.

The third lens 103 may have a refractive power opposite to that of the first lens 101 at the optical axis OA. That is, the third lens 103 may have negative refractive power. The third lens 103 may include a plastic or glass material, for example, a plastic material.

The third lens 103 may include a fifth surface S5 defined as the object side surface and a sixth surface S6 defined as the sensor side surface. The fifth surface S5 may have a concave shape along the optical axis OA, and the sixth surface S6 may have a concave shape along the optical axis OA. That is, the third lens 103 may have a concave shape on both sides of the optical axis OA. Alternatively, the fifth surface S5 may have a convex shape on the optical axis OA, and the sixth surface S6 may have a concave shape on the optical axis OA. That is, the third lens 103 may have a meniscus shape that is convex from the optical axis OA toward the object. At least one of the fifth surface S5 and the sixth surface S6 may be an aspherical surface. For example, both the fifth surface S5 and the sixth surface S6 may be aspherical. The fifth surface S5 and the sixth surface S6 may be provided without a critical point from the optical axis to the end of the effective area.

The object-side first lens 101 of the first lens group G1 may have a refractive power opposite to that of the sensor-side third lens 103. Accordingly, the plurality of lenses 101, 102, and 103 included in the first lens group G1 can compensate for chromatic aberration that occurs. The third lens 103 adjacent to the second lens group G2 in the first lens group G1 may have the highest refractive index in the first lens group G1. For example, the refractive index of the third lens 103 may be 1.6 or less. Accordingly, since the first lens group (G1) controls the dispersion of light provided to the second lens group (G2), the lens size of the second lens group (G2) can be reduced.

The fourth lens 104 may have positive refractive power at the optical axis OA. The fourth lens 104 may include a plastic or glass material, for example, a glass mold material, and may have a refractive index of less than 1.6. The fourth lens 104 may include a seventh surface S7 defined as the object side surface and an eighth surface S8 defined as the sensor side surface. The seventh surface S7 may have a convex shape with respect to the optical axis OA, and the eighth surface S8 may have a convex shape with respect to the optical axis OA. That is, the fourth lens 104 may have a convex shape on both sides of the optical axis OA. Alternatively, the seventh surface S7 may be convex with respect to the optical axis OA, and the eighth surface S8 may be concave with respect to the optical axis OA. That is, the fourth lens 104 may have a meniscus shape that is convex from the optical axis OA toward the object. At least one of the seventh surface S7 and the eighth surface S8 may be an aspherical surface. For example, both the seventh surface S7 and the eighth surface S8 may be aspherical. The seventh surface S7 and the eighth surface S8 may be provided without a critical point from the optical axis to the end of the effective area.

The fifth lens 105 may have positive (+) or negative (-) refractive power at the optical axis (OA). The fifth lens 105 may have the same amount of refractive power as the fourth lens 104 at the optical axis OA. The fifth lens 105 may include a plastic or glass material, for example, a plastic material. The fifth lens 105 may include a ninth surface S9 defined as the object side surface and a tenth surface S10 defined as the sensor side surface. The ninth surface S9 may have a concave shape with respect to the optical axis OA, and the tenth surface S10 may have a convex shape with respect to the optical axis OA. That is, the fifth lens 105 may have a meniscus shape that is convex from the optical axis OA toward the sensor. At least one of the ninth surface S9 and the tenth surface S10 may be an aspherical surface. For example, both the ninth surface S9 and the tenth surface S10 may be aspherical. The ninth surface S9 of the fifth lens 105 may be provided without at least one critical point.

As another example, the ninth surface S9 of the fifth lens 105 may have a convex shape at the optical axis OA, and the tenth surface S10 may have a convex shape at the optical axis OA. . That is, the fifth lens 105 may have a shape in which both sides are convex at the optical axis OA. Alternatively, the ninth surface S9 may have a concave shape along the optical axis OA, and the tenth surface S10 may have a concave shape along the optical axis OA. Differently, the ninth surface S9 may have a convex shape with respect to the optical axis OA, and the tenth surface S10 may have a concave shape with respect to the optical axis OA.

The fourth lens 104 has a convex shape on both sides, and the center thickness CT4 of the fourth lens 104 may be thicker than the edge thickness ET4, for example, twice or more. Accordingly, the gap CG4 between the fourth lens 104 and the fifth lens 105 can be reduced.

The difference in Abbe numbers between the fourth lens 104 and the fifth lens 105 may be greater than 20 or greater than 30, and may be less than 70 at most. Accordingly, the second lens group G2 can minimize the change in chromatic aberration caused by the position changing according to the change in operation mode.

The sixth lens 106 may have positive (+) or negative (-) refractive power at the optical axis OA, for example, negative refractive power. The sixth lens 106 may include a plastic or glass material, for example, a plastic material. The sixth lens 106 may include an 11th surface S11 defined as the object side surface and a 12th surface S12 defined as the sensor side surface. The 11th surface S11 may have a concave shape with respect to the optical axis OA, and the 12th surface S12 may have a convex shape with respect to the optical axis OA. That is, the sixth lens 106 may have a meniscus shape that is convex from the optical axis OA toward the sensor. Alternatively, the 11th surface S11 may have a convex shape along the optical axis OA, and the 12th surface S12 may have a convex shape along the optical axis OA. That is, the sixth lens 106 may have a shape in which both sides are convex at the optical axis OA. Alternatively, the 11th surface S11 may have a concave shape along the optical axis OA, and the 12th surface S12 may have a concave shape along the optical axis OA.

At least one of the 11th surface S11 and the 12th surface S12 of the sixth lens 106 may be aspherical. For example, both the 11th surface (S11) and the 12th surface (S12) may be aspherical. The 11th surface S11 and the 12th surface S12 may be provided without a critical point from the optical axis to the end of the effective area.

The seventh lens 107 may have positive (+) or negative (-) refractive power at the optical axis OA, or may have negative refractive power. The seventh lens 107 has a refractive power opposite to that of the fourth and fifth lenses 104 and 105 on the optical axis OA, thereby improving chromatic aberration. The seventh lens 107 may include a plastic or glass material, for example, a plastic material.

The seventh lens 107 may include a 13th surface S13 defined as the object side surface and a 14th surface S14 defined as the sensor side surface. The 13th surface S13 may have a convex shape with respect to the optical axis OA, and the 14th surface S14 may have a concave shape with respect to the optical axis OA. That is, the seventh lens 107 may have a meniscus shape convex from the optical axis OA toward the object. As another example, the 13th surface S13 may have a convex shape along the optical axis OA, and the 14th surface S14 may have a convex shape along the optical axis OA. That is, the seventh lens 107 may have a shape in which both sides are convex at the optical axis OA. Alternatively, the 13th surface S13 may have a concave shape with respect to the optical axis OA, and the 14th surface S14 may have a convex shape with respect to the optical axis OA. That is, the seventh lens 107 may have a meniscus shape that is convex from the optical axis OA toward the sensor. Alternatively, the 13th surface S13 may have a concave shape along the optical axis OA, and the 14th surface S14 may have a concave shape along the optical axis OA. That is, the seventh lens 107 may have a concave shape on both sides of the optical axis OA. The 13th surface S13 and the 14th surface S14 of the seventh lens 107 may be provided without a critical point from the optical axis to the end of the effective area.

The difference in Abbe number of the fifth lens 105 and the sixth lens 106 is set to 10 or less, so that chromatic aberration can be adjusted. Accordingly, the second and third lens groups G2 and G3 can minimize chromatic aberration changes caused by changes in position according to mode changes and perform an achromatic role.

The seventh lens 107 may have a critical point on at least one of the object-side thirteenth surface S13 and the sensor-side fourteenth surface S14. For example, the fourteenth surface S14 is provided without a critical point. 13 The surface (S13) may have a critical point. The critical point is a point at which the sign of the slope value with respect to the optical axis OA and the direction perpendicular to the optical axis OA changes from positive (+) to negative (-) or from negative (-) to positive (+), and the slope It may mean a point where the value is 0. Additionally, the critical point may be a point where the slope value of a tangent line passing through the lens surface increases and then decreases, or a point where it decreases and then increases.

The difference between the center thickness (CT5) and the edge thickness (ET5) of the fifth lens 105 may be 0.9 or more. The difference between the center thickness (CT6) and the edge thickness (ET6) of the sixth lens 106 may be 0.9 or more. The center thicknesses (CT5, CT6) of the fifth and sixth lenses 105 and 106 may be thicker than those of other lenses and may have the thickest thickness.

The center thickness CT3 of the third lens 103 may have the thinnest center thickness among the lenses. The center thickness CT2 of the second lens 102 may have the second thinnest center thickness among the lenses. The center thickness (CT7) of the seventh lens 107 may be thinner than the edge thickness (ET7). Accordingly, light distribution can be uniformly provided to the periphery of the image sensor 300 due to the difference between the center thickness and the edge thickness of the seventh lens 107.

The third lens group G3 may be closest to the image sensor 300 among the plurality of lens groups G1, G2, and G3. The third lens group (G3) can be moved in the optical axis direction, and the optical axis distance (BFL) between the seventh lens 107 and the image sensor 300 is variable to adjust the focus position according to the operation mode. You can.

The third lens group G3 may play a role in controlling the Chief Ray Angle (CRA). In detail, the CRA of the optical system 1000 according to the embodiment may be less than about 15 degrees, and the seventh lens 107 of the third lens group G3 is the main ray of light incident on the image sensor 300. The angle of incidence (Chief Ray Angle, CRA) can be corrected according to each operation mode.

A camera module (not shown) according to an embodiment of the invention may include the optical system 1000 described above. The camera module can move the second and third lens groups (G2, G3) among the plurality of lens groups (G1, G2, G3) included in the optical system 1000 in the direction of the optical axis (OA). The camera module may include a driving member (not shown) connected to the optical system 1000. The driving member is disposed outside the second lens group G2 and the third lens group G3, and can be moved in the direction of the optical axis OA depending on the operation mode.

The operation mode may include a first mode moving at a first magnification and a third mode operating at a second magnification different from the first magnification. At this time, the second magnification may be greater than the first magnification. Additionally, the operating mode may include a second mode having a magnification between the first and third modes. Here, the first magnification may be the lowest magnification of the optical system 1000, and the second magnification may be the highest magnification of the optical system 1000. The first magnification may be about 2.5 to about 5 times, the second magnification may be about 6 to 11 times, and the third magnification may be between about 4 times and about 2 times the first and second magnifications. It may be 6x magnification. The first mode may be a wide mode, the second mode may be a middle mode, and the third mode may be a tele mode.

The driving member may move the second and third lens groups G2 and G3 or operate them in an initial mode according to one operation mode selected from among the first to third modes. In detail, each of the plurality of driving members is connected to the second lens group (G2) or the third lens group (G3), and is connected to the second lens group (G2) or the third lens group (G3) depending on the operation mode. can be moved. The initial mode may be any one of the first, second, and third modes, for example, the second mode or the middle mode. For example, in the first mode, each of the second lens group G2 and the third lens group G3 may be located at a location defined as the first position (Position 1). In the second mode, each of the second lens group G2 and the third lens group G3 may be located at a position defined as a second position (Position 2), which is closer to the object than the first position. In the third mode, each of the second lens group G2 and the third lens group G3 may be located at a position defined as a third position (Position 3) closer to the sensor side than the first position. The first location may be an area between the second and third locations.

The first position where the second lens group G2 is located in the first mode is an area between the second and third positions where the second lens group G2 is located in the second and third modes. You can. The first position where the third lens group G3 is located in the first mode may be an area between the second and third positions where the third lens group G3 is located in the second and third modes. .

In the optical system 1000 according to the embodiment, the second lens group (G2) and the third lens group (G3) can be moved depending on the operation mode, and the first lens group (G1) can be arranged in a fixed position. You can. Depending on the operation mode, the second lens group (G2) or the third lens group (G3) can be moved, and the first lens group (G1) can be placed in a fixed position. The first to third lens groups G1, G2, and G3 may have a set distance from adjacent lens groups in each of the first, second, and third positions according to the operation mode. Accordingly, the optical system 1000 can have a constant TTL (Total track length) and a variable BFL depending on the operation mode, and the effective focal length and magnification of the optical system 1000 are controlled by controlling the positions of some lens groups. can do.

The effective diameter of the first lens 101 is the largest among the lenses, and the effective diameter of the third lens 103 is the smallest among the lenses. The Abbe number of the fourth lens 104 may be the largest among the lenses and may be 70 or more. In the absolute value of the focal length, the focal length of the fifth lens 105 may be the largest among the lenses, and the difference in focal distance (absolute value) between the two adjacent lenses may be the largest between the fourth and fifth lenses 104 and 105. It may be large, and the difference between the first and second lenses 101 and 102 may be the smallest.

An optical axis gap (DG12) between the first lens group (G1) and the second lens group (G2), and an optical axis gap (DG23) between the second lens group (G2) and the third lens group (G3) has a minimum of 0.2 mm or more depending on the operation mode, and can be a maximum of 8 mm or less. Depending on the operation mode, the F number of the optical system 1000 provides brightness of 2.0 or more, and the F number may be in the range of 2.2 to 3.8. The aperture may be located between the first lens group (G1) and the second lens group (G2).

The optical system 1000 according to the embodiment may satisfy at least one or two of the equations described below. Accordingly, the optical system 1000 according to the embodiment can effectively correct aberrations that change depending on the operation mode change. Additionally, the optical system 1000 according to the embodiment can effectively provide an autofocus (AF) function for subjects at various magnifications and can have a slim and compact structure.

Hereinafter, the center thickness of the first to seventh lenses 101-107 may be defined as CT1-CT7, the edge thickness may be defined as ET1-ET7, and the optical axis spacing between two adjacent lenses may be defined as the first and second lenses. From the gap between lenses to the gap between the 6th and 7th lenses, it can be defined as CG1-CG6. The average effective diameter of the object-side surface and the sensor-side surface of the first to seventh lenses 101-107 can be defined as CA1-CA7, starting from the effective diameter of the object-side surface and the sensor-side surface of the first lens 101. 7 The effective diameters of the object side and sensor side of the lens 107 can be defined as CA11 and CA12 to CA71 and CA72. The unit of the thickness, spacing, and effective diameter values is mm. Additionally, the effective diameter is when the lens is circular or partially circular, and when the lens is partially circular, it can be defined as the effective diameter or maximum diameter.

[Equation 1]

n_G1, n_G2, n_G3 > 1 (n_G1, n_G2, n_G3 are natural numbers)

In Equation 1, n_G1, n_G2, and n_G3 mean the number of lenses included in each of the first to third lens groups (G1, G2, and G3). Here, the relationship may be n_G1 > n_G2 and n_G1 > n_G3.

[Equation 2]

0.7 < CA41 / CA11 < 1.2

In Equation 2, CA41 is the maximum effective diameter of the seventh surface (S7) of the fourth lens 104, and CA11 is the maximum effective diameter of the first surface (S1) of the first lens 101. If Equation 2 is satisfied, a higher Entrance Pupil Diameter (EPD) can be provided compared to optical systems.

[Equation 3]

2 < CT1 / CT3 < 5

In Equation 3, CT1 is the thickness (mm) at the optical axis of the first lens 101, and CT3 is the thickness at the optical axis of the third lens 103. If Equation 3 is satisfied, the aberration specification in the optical system 1000 can be improved. Preferably, 2.5 < CT1 / CT3 < 4 may be satisfied.

[Equation 4]

0 < CT1 / CT4 < 1.5

In Equation 4, CT3 refers to the thickness (mm) of the fourth lens 104 at the optical axis (OA). When the optical system 1000 according to the embodiment satisfies Equation 4, the optical system 1000 can improve aberration characteristics. Preferably, 0.5 < CT1 / CT4 < 1 may be satisfied.

[Equation 5]

0 < ET3 / CT3 < 1

In Equation 4, ET3 means the thickness (mm) in the optical axis (OA) direction at the edge, which is the end of the effective area of the third lens 103. When the optical system 1000 according to the embodiment satisfies Equation 5, the optical system 1000 can improve distortion characteristics. Preferably, 0.3 < ET3 / CT3 < 0.7 may be satisfied.

[Equation 6]

G1F < 0

In Equation 6, G1F is the effective focal length (EFL) of the first lens group (G1), and may have a value less than 0. This is the composite focal length of the first to third lenses. When Equation 6 is satisfied, the optical aberration of the optical system or the optical aberration of the first lens group G1 can be improved.

[Equation 7]

CRA < 20

In Equation 7, CRA (Chief Ray Angle) is the main ray incident angle. Depending on the first, second, and third modes in the optical system, the main ray angle may be less than 20 degrees at most, for example, 15 degrees or less. The first mode may be a wide mode, the second mode may be a middle mode, and the third mode may be a tele mode. Here, in the case of the first mode (Wide), the main ray incident angle may be greater than the main ray incident angle in the case of the second mode in the 1.0 field. In the case of the third mode (Tele), the main ray incident angle in a 1.0 field may be 11 degrees or less, and the main ray incident angle of the second mode may be smaller than the main ray incident angle of the first mode. If Equation 6 is satisfied, the ambient light ratio can be secured.

[Equation 8]

3.5 < (TTL/DG1)

In Equation 8, DG1 is the optical axis distance of the first lens group (G1), for example, the optical axis distance from the center of the object-side surface of the first lens 101 to the center of the sensor-side surface of the third lens 103. . For example, DG1 refers to the distance (mm) between the first surface (S1) of the first lens 101 and the sixth surface (S6) of the third lens 103 from the optical axis (OA). . Total track length (TTL) refers to the distance (mm) on the optical axis (OA) from the object-side first surface (S1) of the first lens 101 to the upper surface of the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 8, the optical system 1000 has a relatively small TTL and can secure the peripheral light ratio. Preferably, 4 < (TTL / DG1) < 6 can be satisfied.

[Equation 9]

2 < TTL / EPD3 < 7

In Equation 9, EPD3 refers to the entrance pupil diameter (EPD) of the optical system 1000 when operating in the third mode, that is, Tele mode. If the optical system 1000 according to the embodiment satisfies Equation 9, the optical system 1000 can secure a bright image when operating in the third mode, and can secure an F number of 4 or less in tele mode. This may be the minimum condition for this. Preferably, 3 < TTL / EPD3 < 5 may be satisfied.

[Equation 9-1] 3 < TTL / EPD1 < 7

[Equation 9-2] 2 < TTL / EPD2 < 6

[Equation 9-3] (TTL/EPD3) < (TTL/EPD2) < (TTL/EPD1)

In Equations 9-1 to 9-3, EPD1 is the size of the entrance pupil of the optical system in the first mode (Wide), and EPD2 is the size of the entrance pupil of the optical system in the second mode (Middle). If the optical system satisfies the above conditions, it can secure a bright image according to each mode.

[Equation 10]

2 < CT_Max / CT_Min < 6

In Equation 10, CT_Max is the thickest central thickness of the lenses, and CT_Min is the thinnest central thickness of the lenses. If Equation 10 is satisfied, the aberration characteristics of the optical system can be improved. Preferably, 3 < CT_Max / CT_Min < 5.5 may be satisfied.

[Equation 11]

1 < CA_Max / CA_Min < 3

In Equation 11, CA_Max is the largest effective diameter among the lenses, and CA_Min is the smallest effective diameter among the lenses. If Equation 11 is satisfied, the optical performance of the optical system can be maintained and a camera module for a slim or compact structure can be provided. You can.

[Equation 12]

0.1 < ΣCG_Wide /TTL < 0.6

In Equation 12, ΣCG_Wide is the sum of the center spacings between adjacent lenses in the first mode. If the optical system satisfies Equation 12, the center distance (DG12) between the first and second lens groups and the center distance between the second and third lens groups can be set according to the wide mode. The center distance DG12 between the first and second lens groups may be the center distance CG3 between the third and fourth lenses 103 and 104, and varies depending on the operation mode. The center distance DG23 between the second and third lens groups is the center distance CG5 between the fifth and sixth lenses 105 and 106, and varies depending on the operation mode.

[Equation 12-1]

0.05 < ΣCG_Mid /TTL < 0.4

[Equation 12-2]

0 < ΣCG_Tele /TTL < 0.3

In Equations 12-1 and 12-2, ΣCG_Mid is the sum of center spacings between adjacent lenses in the second mode, and ΣCG_Tele is the sum of center spacings between adjacent lenses in the third mode. If the optical system satisfies equations 12-1 and 12-2, the center spacing (DG12) between the first and second lens groups and the center spacing between the second and third lens groups can be set according to the middle mode and tele mode. .

When the optical system 1000 according to an embodiment satisfies at least one or two of Equations 1 to 12, the optical system 1000 may have a slim structure. Additionally, the optical system 1000 has improved assembly properties and can have a mechanically stable form.

[Equation 13]

0.5 < DG1 / DG2 < 3

In Equation 13, DG1 is the optical axis distance of the first lens group (G1), for example, between the first surface (S1) of the first lens 101 and the sixth surface (S6) of the third lens 103. This refers to the optical axis distance. DG2 is the optical axis distance of the second lens group (G2), for example, the optical axis distance between the seventh surface (S7) of the fourth lens 104 and the tenth surface (S10) of the fifth lens 105. means. In Equation 13, the TTL can be adjusted by setting the optical axis distance of the first and second lens groups (G1, G2). Preferably, 0.5 < DG1 / DG2 < 1 may be satisfied.

[Equation 14]

0.5 < DG2 / DG3 < 2

In Equation 14, DG2 is the optical axis distance of the second lens group (G2), for example, between the seventh surface (S7) of the fourth lens 104 and the tenth surface (S6) of the fifth lens 105. This refers to the optical axis distance. DG3 refers to the optical axis distance of the third lens group (G3), for example, the optical axis distance between the 11th surface (S11) of the sixth lens 106 and the 14th surface (S14) of the seventh lens 107. do. Preferably, 0.8 < DG2 / DG3 < 1.5 may be satisfied. When the optical system 1000 according to the embodiment satisfies at least one of Equation 13 and Equation 14, it has a relatively small TTL and can provide various magnifications according to changes in at least three modes.

[Equation 15]

0 < CG2 / TTL < 0.2

In Equation 15, CG2 is the optical axis spacing between the second lens 102 and the third lens 103. When the optical system 1000 satisfies Equation 15, the optical system 1000 has a relatively small TTL and can have improved optical characteristics by controlling stray light incident on the first lens group G1. there is. Preferably, 0 < CG2 / TTL < 0.1 may be satisfied.

[Equation 16]

3 < TTL/DG2 < 10

In Equation 16, DG2 is the optical axis distance of the second lens group (G2). When the optical system 1000 according to the embodiment satisfies Equation 16, the optical system 1000 has a relatively small TTL and can improve chromatic aberration characteristics.

[Equation 17]

20 < |Vd4 - Vd5| < 70

In Equation 17, Vd4 refers to the Abbe Number of the fourth lens 104, and Vd5 refers to the Abbe Number of the fifth lens 105. When the absolute value of the difference in Abbe numbers of the fourth and fifth lenses satisfies Equation 17, the optical system 1000 according to the embodiment can improve chromatic aberration characteristics.

[Equation 18]

15 < |Vd7 - Vd6| < 60

In Equation 18, Vd7 refers to the Abbe number of the seventh lens, and Vd6 refers to the Abbe number of the sixth lens. When the absolute value of the difference in Abbe numbers of the sixth and seventh lenses satisfies Equation 18, the optical system 1000 can improve chromatic aberration characteristics.

[Equation 19]

1.6 < n2

In Equation 19, n2 means the refractive index at the d-line of the second lens 102. When the optical system 1000 according to the embodiment satisfies Equation 19, incident light can be dispersed and the effective area of the lens disposed after the second lens 102 can be secured. The refractive index of the fourth and seventh lenses 104 and 107 may be less than 1.6, and the refractive index of the fourth lens 104 may be the smallest among the lenses. Among the above lenses, the number of lenses having a refractive index of 1.63 or more is two or more.

[Equation 20]

1 < L1R1 / L3R2 < 2.5

In Equation 20, L1R1 refers to the radius of curvature of the first surface S1 on the object side of the first lens 101, and L3R2 refers to the radius of curvature of the sixth surface S6 on the sensor side of the third lens 103. it means. When the optical system 1000 according to the embodiment satisfies Equation 20, the optical system 1000 can control stray light incident on the first lens group G1.

[Equation 21]

1.5 < L1R1 / L4R1 < 3.5

In Equation 21, L1R1 refers to the radius of curvature of the first surface (S1) on the object side of the first lens 101, and L4R1 refers to the radius of curvature of the seventh surface (S7) on the object side of the fourth lens 104. do. When the optical system 1000 according to the embodiment satisfies Equation 21, the optical system 1000 can have good optical performance at various magnifications.

[Equation 22]

0 < L3R2 / L4R1 < 2

In Equation 22, L3R2 refers to the radius of curvature of the sixth surface (S6) on the sensor side of the third lens 103, and L4R1 refers to the radius of curvature of the seventh surface (S7) on the object side of the fourth lens 104. means. When the optical system 1000 according to the embodiment satisfies Equation 22, the optical system 1000 can have good optical performance in the peripheral area of the field of view (FOV) when operating at various magnifications in at least three modes.

[Equation 23]

1 < L1R1 / L7R2 < 3

In Equation 23, L1R1 refers to the radius of curvature of the first surface (S1) on the object side of the first lens 101, and L7R2 refers to the radius of curvature of the fourteenth surface (S14) on the sensor side of the seventh lens 107. means. When the optical system 1000 according to the embodiment satisfies Equation 23, the optical system 1000 may have good optical performance in the center and peripheral areas of the field of view (FOV).

[Equation 24]

0 < Mode12_mG2 / TTL < 0.5

In Equation 24, Mode12_mG2 means the center spacing difference (unit, mm) after movement of the second lens group G2 when changing from the second mode to the first mode or from the first mode to the second mode. . In detail, Mode12_mG2 represents the moving distance of the second lens group (G2) in the first and second modes, and the optical axis spacing between the first and second lens groups (G1, G2) in the first mode and It means the difference value between the optical axis spacing between the first and second lens groups G1 and G2 in the second mode. When the optical system 1000 according to the embodiment satisfies Equation 24, the optical system 1000 can minimize the moving distance of the second lens group G2 when changing magnification, so that the optical system 1000 has a slim appearance. It can have a structure. Additionally, the moving distance can be minimized when controlling the position of the second lens group G2, resulting in improved power consumption characteristics.

[Equation 25]

0 < Mode23_mG2 / TTL < 0.5

In Equation 25, Mode23_mG2 is the center spacing difference (unit, mm) after movement of the second lens group G2 when operating from the second mode to the third mode, or from the third mode to the second mode. it means. In detail, Mode23_mG2 is the optical axis spacing between the first and second second lens groups (G1, G2) in the second mode and the optical axis spacing between the first and second lens groups (G1, G2) in the third mode. means the difference value. The maximum moving distance of the second lens group (G2) may be greater than the maximum moving distance of the third lens group (G3). When the optical system 1000 according to the embodiment satisfies Equation 25, the optical system 1000 can minimize the moving distance of the second lens group (G2) when changing magnification, so that the optical system 1000 has a slim structure. You can have Additionally, the moving distance can be minimized when controlling the position of the second lens group G2, resulting in improved power consumption characteristics.

[Equation 26]

0.3 < Mode12_mG2 / DG2 < 1

Equation 26 is Mode12_mG2, when operating from the first mode to the second mode, or from the second mode to the first mode, the center spacing difference (unit, mm) after movement of the second lens group (G2) it means. When the optical system 1000 according to the embodiment satisfies Equation 26, the optical system 1000 can minimize the moving distance of the second lens group (G2) when changing magnification, so that the optical system 1000 has a slim structure You can have Additionally, the moving distance can be minimized when controlling the position of the second lens group G2, resulting in improved power consumption characteristics. DG2 is the optical axis distance of the second lens group (G2). When the optical system 1000 according to the embodiment satisfies Equation 26, the optical system 1000 can minimize the moving distance of the second lens group (G2) when changing magnification, so that the optical system 1000 has a slim structure You can have Additionally, the moving distance can be minimized when controlling the position of the second lens group G2, resulting in improved power consumption characteristics.

[Equation 27]

0 < Mode23_mG3 / DG3 < 0.5

In Equation 27, Mode23_mG3 means the difference in center spacing after movement of the third lens group G3 when changing from the second mode to the third mode, or from the third mode to the second mode. DG3 is the optical axis distance of the third lens group (G3). When the optical system 1000 according to the embodiment satisfies Equation 27, the optical system 1000 can minimize the moving distance of the third lens group G3 when changing magnification, so that the optical system 1000 has a slim structure. You can have Additionally, the moving distance can be minimized when controlling the position of the third lens group G3, resulting in improved power consumption characteristics.

[Equation 28]

0 < (CT1/ET1) / (CT3/ET3) < 1

In Equation 28, CT1/ET1 is the thickness at the optical axis of the first lens 101 divided by the thickness at the end, and CT3/ET3 is the thickness at the optical axis of the third lens 103 divided by the thickness at the end. It is the divided value. If the value obtained by dividing the center thickness and the end thickness of the first and third lenses 101 and 103 satisfies Equation 28 at the above ratio, chromatic aberration can be improved and incident light can be controlled.

[Equation 29]

0.5 < (CT1/ET1) / (CT7/ET7) < 1.5

In Equation 29, CT1/ET1 is a value obtained by dividing the thickness at the optical axis of the seventh lens 107 by the thickness at the end. When the values obtained by dividing the center thickness and the end thickness of the first and seventh lenses 101 and 107 satisfy Equation 29 at the above ratio, chromatic aberration can be improved and incident light can be controlled.

[Equation 30]

1 < Mode1(DG12/DG23) < 5

In Equation 30, Mode1(DG12/DG23) represents the ratio between the center spacing (DG12) between the first and second lens groups in the first mode and the center spacing (DG23) between the second and third lens groups. When the optical system 1000 according to the embodiment satisfies Equation 30, the optical system 1000 may have improved optical characteristics at the first magnification. In detail, the optical system 1000 may have improved aberration characteristics at the first magnification and may improve optical performance in the center and periphery of the field of view (FOV).

[Equation 31]

0 < Mode3(DG12/DG23) < 0.7

In Equation 31, Mode3(DG12/DG23) represents the ratio between the center distance between the first and second lens groups (DG12) and the center distance between the second and third lens groups (DG23) in the third mode. When the optical system 1000 according to the embodiment satisfies Equation 31, the optical system 1000 may have improved optical characteristics at the second magnification. In detail, the optical system 1000 has improved aberration characteristics at the second magnification and can improve optical performance in the peripheral area of the field of view (FOV).

[Equation 32]

0.5 < TD2/TTL < 1

In Equation 32, TD2 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the seventh lens in the second mode. When the optical system 1000 according to the embodiment satisfies Equation 32, the optical system 1000 may have improved optical characteristics in middle mode. In detail, the optical system 1000 has improved aberration characteristics in middle mode and can improve optical performance in the peripheral area of the field of view (FOV).

[Equation 33]

0.7 < TD1/TD2 < 1.5

In Equation 33, TD1 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the seventh lens in the first mode. When the optical system 1000 according to the embodiment satisfies Equation 33, the optical system 1000 may have improved optical characteristics in the first and second modes. In detail, the optical system 1000 has improved aberration characteristics in the first and second modes and can improve optical performance in the peripheral area of the field of view (FOV).

[Equation 34]

12mm < TD3 < TD2 < TD1 < 20mm

Equation 34 is a diagram comparing the optical axis distances of the lenses in the first, second, and third modes, and TD3 is the distance from the center of the object side of the first lens to the center of the sensor side of the seventh lens in the third mode. It is the optical axis distance. When the optical system 1000 according to the embodiment satisfies Equation 34, the optical system 1000 may have improved optical characteristics in the first, second, and third modes. In detail, the optical system 1000 has improved aberration characteristics in the first, second, and third modes and can improve optical performance in the peripheral area of the field of view (FOV).

[Equation 35]

0.1 < BFL2/TTL < 1

In Equation 35, BFL2 (Back focal length1) is the optical axis distance from the center of the sensor side of the seventh lens to the image surface of the image sensor in the second mode. When the optical system 1000 according to the embodiment satisfies Equation 35, the optical system 1000 can adjust the focus position on the image sensor 300 in the second mode. In detail, the optical system 1000 has improved optical characteristics in the second mode and can improve optical performance in the peripheral area of the field of view (FOV). Preferably, 0.1 < BFL2/TTL < 0.5 may be satisfied.

[Equation 36]

2 < BFL3/BFL1 < 4

In Equation 36, BFL3 is the optical axis distance from the center of the sensor side of the seventh lens to the image surface of the image sensor in the third mode. When the optical system 1000 according to the embodiment satisfies Equation 36, the optical system 1000 can adjust the focus position on the image sensor 300 in the first and third modes. In detail, the optical system 1000 has improved optical characteristics in the first and third modes and can improve optical performance in the peripheral area of the field of view (FOV). Preferably, 2 < BFL3/BFL1 < 3.3 may be satisfied.

[Equation 37]

1.5 < TD3 / BFL3 < 3

Equation 37 is the optical axis distance (TD3) between the center of the object-side surface of the first lens and the center of the sensor-side surface of the seventh lens in the third mode, and the center of the sensor-side surface of the seventh lens 107. This is a comparison of the optical axis distance (BFL3) to the top surface of the image sensor. When the optical system 1000 according to the embodiment satisfies Equation 37, the optical system 1000 may have improved optical characteristics in the third mode. In detail, the optical system 1000 has improved aberration characteristics in the third mode and can improve optical performance in the peripheral area of the field of view (FOV).

[Equation 38]

2 < Mode_CG_Max / Mode_CG_Min < 8

In Equation 38, Mode_CG_Max means the maximum center spacing among the center spacings between the first to seventh lenses in the first, second, and third modes, and Mode_CG_Min refers to the maximum center spacing between the first to seventh lenses in the first, second, and third modes. 7 This refers to the minimum center distance among the center distances between lenses. If the optical system satisfies Equation 38, the TTL and optical axis distance of the lenses for each mode can be adjusted.

[Equation 39]

1 < BFL1 < 5

Equation 39 represents the optical axis spacing between the seventh lens and the image sensor in the first mode. If the optical system satisfies Equation 39, the focus position on the image sensor in the first mode can be adjusted.

[Equation 40]

30 < Aver_Abbe < 50

In equation 40, Aver_Abbe is the average Abbe number of the first to seventh lenses. When the optical system satisfies Equation 40, the optical system 1000 can have improved aberration characteristics and resolution.

[Equation 41]

1.5 < Aver_Index < 1.8

In Equation 40, Aver_Index is the average refractive index of the first to seventh lenses. When the optical system satisfies Equation 41, the optical system 1000 can have improved aberration characteristics and resolution.

[Equation 41-1]

10 < ∑Abbe / ∑Index < 40

In Equation 41-1, ²Abbe means the sum of the Abbe numbers of each of the plurality of lenses. ²Index means the sum of the refractive indices of each of the plurality of lenses. When the optical system 1000 according to the embodiment satisfies Equation 41-1, the optical system 1000 may have improved aberration characteristics and resolution. Preferably, Equation 41-1 may satisfy 20 < ∑Abbe / ∑Index < 35. Preferably, the condition of (∑Abb - ∑Index) < 300 can be satisfied.

[Equation 42]

2 < │ G1F/G2F │ < 4

In Equation 42, G1F represents the effective focal length (EFL) of the first lens group (G1), and G2F represents the effective focal length of the second lens group (G2). G2F is the composite focal length of the fourth and fifth lenses. If Equation 42 is satisfied, the size of the optical system can be reduced, for example, the total track length (TTL) can be reduced. Preferably, G2F > 0 is satisfied. G3f is the composite focal length of the sixth to seventh lenses, G3F < 0, and the condition of │ G1F │ > │G3F │ > G2F can be satisfied.

[Equation 43]

1 < M2F/M1F < 10

In equation 43, M1F is the effective focal length of the optical system in the first mode, and M2F is the effective focal length of the optical system in the second mode. Preferably, 1 < M2F/M1F < 3 may be satisfied. If the optical system satisfies Equation 43, the effective focal length can be adjusted according to the first and second modes.

[Equation 43-1]

1 < M3F/M2F < 10

In equation 43, M3F is the effective focal length of the optical system in the third mode. Preferably, 1 < M3F/M2F < 3 may be satisfied, and the condition (M3F/M1F) > (M3F/M2F) may be satisfied. If the optical system satisfies Equation 43-1, the effective focal length can be adjusted according to the second and third modes.

[Equation 44]

2 < M2F / EPD2 < 7

In Equation 44, M2F is the effective focal length of the optical system in the second mode (Middle), and EPD2 means the entrance pupil diameter (EPD) of the optical system 1000 in the second mode. When the optical system 1000 according to the embodiment satisfies Equation 44, the optical system 1000 can secure a bright image when operating in the second mode.

[Equation 45]

0.1 < M1F / EPD1 < 3

In Equation 34, M1F is the effective focal length of the optical system in the first mode (Wide), and EPD1 means the entrance pupil diameter (EPD) of the optical system 1000 when operating in the first mode. When the optical system 1000 according to the embodiment satisfies Equation 45, the optical system 1000 can secure a bright image when operating in the first mode.

[Equation 46]

M1F < M2F < M3F

In Equation 46, M1F, M2F, and M3F mean the effective focal lengths of the optical system in the first, second, and third modes. The effective focal distance in the third mode may be the largest, and the effective focal distance in the first mode may be the smallest.

[Equation 47]

0 <TTL/M2F<2

Equation 47 compares the TTL and the effective focal length in the second mode to adjust the TTL. Preferably, 1 < TTL / M2F < 2 may be satisfied.

[Equation 48]

0.1 <TTL/M1F<5

Equation 47 compares the TTL and the effective focal length in the first mode to adjust the TTL. Preferably, 1 < TTL / M1F < 4 may be satisfied.

[Equation 49]

1 < CA_Max / ImgH < 3

In Equation 49, CA_Max means the size of the largest effective diameter (CA) among the lens surfaces of the plurality of lenses 100 included in the optical system 1000. ImgH is the distance from the 0 field (field) area of the image center of the image sensor 300 that overlaps the optical axis (OA) to the 1.0 field (field) area of the image sensor 300. The ImgH means 1/2 of the diagonal length of the effective area of the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 49, the optical system 1000 can be provided in a slim and compact manner. Additionally, the optical system 1000 can implement high resolution and high image quality. The range of ImgH is 2mm to 3mm.

[Equation 50]

5 <TTL/ImgH<12

When the optical system 1000 satisfies Equation 39, the optical system 1000 can have a smaller TTL, so the optical system 1000 can be provided in a slim and compact manner. Preferably, the range may be 6 < TTL / ImgH < 10.

[Equation 51]

1 < BFL2 / ImgH < 3

When the optical system 1000 according to the embodiment satisfies Equation 51, the BFL required for a small image sensor of less than 1 inch can be secured. In addition, when the optical system 1000 satisfies Equation 51, the optical system 1000 can operate at various magnifications while maintaining TTL and can have excellent optical characteristics in the center and periphery of the field of view (FOV). Preferably, it may be in the range of 2 < BFL2 / ImgH < 3.

[Equation 52]

2 < BFL3 / ImgH < 4

When the optical system 1000 according to the embodiment satisfies Equation 52, the BFL required for a small image sensor of less than 1 inch can be secured. In addition, when the optical system 1000 satisfies Equation 51, the optical system 1000 can operate at various magnifications while maintaining TTL and can have excellent optical characteristics in the center and periphery of the field of view (FOV). Preferably, 2.5 < BFL3 / ImgH < 3.5 may be satisfied.

[Equation 53]

1 < EPD1 < EPD2 < EPD3 < 7

In Equation 53, EPD1, EPD2, and EPD3 represent the size of the entrance pupil of the optical system according to the first to third modes, and the brightness according to each mode can be adjusted.

[Equation 54]

0 < Max_Distortion < 3

In Equation 54, distortion is the maximum value or maximum value of distortion from the center of the image sensor (0.0F) to the diagonal end (1.0F) based on the optical characteristics detected by the image sensor 300. it means. When the optical system 1000 satisfies Equation 54, the optical system 1000 can improve distortion characteristics and set conditions for image processing. Preferably, Distortion < 1.5 can be satisfied.

[Equation 55]

8 < FOV3 < FOV2 < FOV1 < 45

In Equation 55, FOV1, FOV2, and FOV3 mean the diagonal view angles of the optical system in the first, second, and third modes. Field of view (FOV) refers to the diagonal angle of view of the optical system 1000, and can provide an optical system of less than 45 degrees.

[Equation 56]

In Equation 56, Z is Sag and can mean the distance in the optical axis direction from an arbitrary position on the aspherical surface to the vertex of the aspherical surface. Additionally, Y may mean the distance from any location on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. Additionally, c may refer to the curvature of the lens, and K may refer to the Conic constant. Additionally, A, B, C, D, E, and F may mean aspheric constants.

The optical system 1000 according to the embodiment may satisfy at least one of Equations 1 to 55 described above. Accordingly, the optical system 1000 and the camera module may have improved optical characteristics. In detail, as the optical system 1000 satisfies at least one or two of Equations 1 to 55, chromatic aberration, vignetting, diffraction effect, and deterioration of image quality in the peripheral area caused by movement of the lens group. Deterioration of optical properties such as deterioration can be effectively corrected. Additionally, the optical system 1000 according to the embodiment can significantly reduce the moving distance of the lens group and provide an autofocus (AF) function for various magnifications with excellent power consumption characteristics.

As the optical system 1000 according to the embodiment satisfies at least one or two of Equations 1 to 55, it has improved assembly properties, can have a mechanically stable form, and is provided in a slim structure, so that the optical system (1000) and the camera module including it may have a compact structure.

Hereinafter, the optical system 1000 and first to third mode changes according to the embodiment will be described in more detail. In the optical system 1000 according to the embodiment, the first lens group (G1) may be fixed and the second lens group (G2) and the third lens group (G3) may be moved according to the operation mode. The first lens group G1 may include a three-element lens, for example, the first to third lenses 101, 102, and 103, and the second lens group G2 may include a two-element lens, for example, the first to third lenses 101, 102, and 103. It may include fourth and fifth lenses 104 and 105. Additionally, the third lens group G3 may include two lenses, for example, the sixth to seventh lenses 106 and 107.

In the optical system 1000 according to the embodiment, the object side surface (seventh surface S7) of the fourth lens 104 may serve as an aperture, and the fourth lens group G4 and the image sensor ( The optical filter 500 described above may be disposed between 300).

Figure 5 shows the radius of curvature at the optical axis (OA) of the first to seventh lenses 101-107, the central thickness (CT) of the lens, and the center spacing between adjacent components, such as lenses ( CG), refractive index at d-line, Abbe's Number and effective diameter or effective diameter (CA).

In FIG. 5, DG4 is the optical axis distance between the seventh lens and the optical filter 500, and may vary depending on the movement of the third lens group G3.

Lens group lens CT/ET 1st lens group first lens 1.281 second lens 1.198 third lens 0.455 2nd lens group 4th lens 2.478 5th lens 0.985 Third lens group 6th lens 0.966 7th lens 0.812

Referring to Table 1, the ratio (CT/ET) of the center thickness (CT) and edge thickness (ET) of each lens of the plurality of lenses 100 may be different from each other, and the ratio (CT/ET) of the fourth lens 104 may be different from each other. The CT/ET value may be the highest, and the third lens may have the smallest CT/ET value. The number of lenses with a CT/ET value of less than 1 may be 4 or less, and may include the 2nd, 5th, 6th, and 7th lenses, and the number of lenses with a CT/ET value of 2 or more may be 1, and may include the 4th lens. 1 and 2, the Abbe number (Vd4) of the fourth lens 104 included in the second lens group (G2) is the Abbe number (Vd5) of the fifth lens 105. ) and can be as high as 30 or higher or 40 or higher. As the fourth lens 104 and the fifth lens 105 have the above-described Abbe number difference, the chromatic aberration change that occurs when the magnification changes due to the movement (M1) of the second lens group (G2) can be minimized. You can.

1 and 3, the Abbe number (Vd7) of the seventh lens 107 included in the third lens group (G3) is 20 or more than the Abbe number (Vd6) of the sixth lens 106. It can be higher than 30. As the seventh lens 107 and the seventh lens 107 have the above-described Abbe number difference, the chromatic aberration change that occurs when the magnification changes due to the movement (M2) of the third lens group (G3) is minimized and /Or it can perform an achromatic role by compensating.

A camera module according to an embodiment can obtain information about a subject at various magnifications. In detail, the driving member can control the positions of the second lens group (G2) and the third lens group (G3), and through this, the camera module can operate at various magnifications. For example, referring to FIGS. 1, 7, and 10, the camera module including the optical system 1000 may operate in the first mode with a first magnification. The first magnification may be about 3 times to about 5 times. In detail, in an embodiment, the first magnification may be about 3.5 times.

In the first mode, each of the second lens group G2 and the third lens group G3 may be moved to a set position. Accordingly, each of the first to third lens groups G3 may be arranged at set intervals. For example, the second lens group (G2) is separated from the first lens group (G1) by a first distance (DG12), and the third lens group (G3) is separated from the second lens group (G2) by a first distance (DG12). It can be located in areas spaced apart by a gap (DG23). Here, the first to second intervals DG12 and DG23 may refer to the interval between the lens groups on the optical axis OA and may vary depending on the operation mode.

When the camera module operates in the first mode, the optical system 1000 may have a total track length (TTL) value and a BFL1 value at the first position. Additionally, the optical system 1000 may have M1F defined as a first effective focal length (EFL) at the first position. Additionally, in the first mode, the angle of view (FOV) of the camera module may be less than about 35 degrees, and the F-number may be less than about 3.

When the camera module operates in the second mode, the optical system 1000 may have a total track length (TTL) value and a BFL2 value at the second position. Additionally, the optical system 1000 may have M2F defined as a second effective focal length (EFL) at the second position. Additionally, in the second mode, the angle of view (FOV) of the camera module may be less than about 25 degrees, and the F-number may be less than about 3.4.

When the camera module operates in the third mode, the optical system 1000 may have a total track length (TTL) value and a BFL3 value at the third position. Additionally, the optical system 1000 may have M3F defined as a third effective focal length (EFL) at the third position. Additionally, in the third mode, the angle of view (FOV) of the camera module may be less than about 20 degrees, and the F-number may be less than about 4.

As shown in FIG. 6, the relative illuminance (RI) in each mode can change depending on the height of the image sensor, and the relative illuminance at the periphery or edge of the image sensor appears to be 50% or more.

The optical system 1000 may have excellent aberration characteristics as shown in FIGS. 7 and 10 in the first mode. In detail, FIG. 7 is a graph of the diffraction MTF characteristics of the optical system 1000 operating in the first mode (first magnification), and FIG. 10 is a graph of the aberration characteristics. The diffraction (Diffraction) MTF characteristic graph is measured in about 0.252mm units over a spatial frequency range of 0.000 mm to 2.2520 mm. In the diffraction MTF graph, T represents the MTF change in spatial frequency per millimeter on the tangential, and R represents the MTF change in spatial frequency per millimeter on the radiating source. Here, the Modulation Transfer Function (MTF) depends on the spatial frequency in cycles per millimeter.

The aberration graph in Figure 10 is a graph measuring spherical aberration, astigmatic field curves, and distortion from left to right. In FIG. 7, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. Additionally, the graph for spherical aberration is a graph for light in the wavelength band of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graph for astigmatism and distortion is a graph for light in the 546 nm wavelength band. In the aberration diagram of FIG. 10, it can be interpreted that the closer each curve is to the Y-axis, the better the aberration correction function. Referring to FIG. 10, the optical system 1000 according to the embodiment has measured values in most areas along the Y-axis. It can be seen that it is adjacent to .

Table 2 and Figure 3 relate to the items of the above-described equations in the optical system 1000 of the embodiment, including total track length (mm), back focal length (BFL), and effective focal length (mm) of the optical system 1000. F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), TD (mm), the optical axis distance from the first side (S1) to the fourteenth side (S14) ), focal length of each of the first to seventh lenses (F1, F2, F3, F4, F5, F6, F7) (mm), sum of refractive indices of each lens, sum of Abbe number of each lens, center of each lens It is about the sum of thickness (mm), the sum of center spacing between adjacent lenses, effective diameter, diagonal angle of view (FOV) (Degree), edge thickness (ET), focal length of the first and second lens groups, F number, etc.

item Example F1 25.22 F2 25.96 F3 -6.22 F4 5.50 F5 391.02 F6 -29.33 F7 -24.72 G1F -21.32 G2F 6.92 G3F -11.78 ET1 1.390 ET2 0.604 ET3 1.233 ET4 0.787 ET5 2.844 ET6 2.900 ET7 1.299 ΣIndex 11.150 ΣAbbe 307.358 ΣCT 11.671 ΣCG_Wide 8.782 ∑CG_Mid 6.025 ∑CG_Tele 3.933 ImgH 2.52 TTL 24

Table 3 shows the center spacing between the first and second lens groups according to the first to third modes, the center spacing between the second and third lens groups, the center spacing (DG4) between the seventh lens and the optical filter, and the center spacing (DG4) between the seventh lens and the optical filter for each mode. Effective focal length (EFL) for each mode, entrance pupil size (EPD) for each mode, and optical axis distance (TD) of the lens for each mode. This shows the F number, angle of view, and BFL for each mode.

item 1st mode 2nd mode third mode DG12 (mm) 4.888 2.871 0.788 DG23 (mm) 2.112 1.371 1.363 DG4 (mm) 2.411 5.204 7.202 EFL(M1F/M2F/M3F) 10.30 14.10 19.01 EPD(EPD1/EPD2/EPD3) 4.288 4.781 5.426 TD(TD1/TD2/TD3) 20.453 17.695 15.604 F-number 2.402 2.949 3.504 FOV (degrees) 27.850 20.338 15.080 BFL (BFL1/BFL2/BFL3) 2.653 6.182 7.553

Tables 4 and 5 provide result values for Equations 1 to 55 described above in the optical system 1000 of the embodiment. Referring to Table 5, it can be seen that the optical system 1000 satisfies at least one, two, or three of Equations 1 to 55. In detail, it can be seen that the optical system 1000 according to the embodiment satisfies all of Equations 1 to 55 above. Accordingly, the optical system 1000 can have good optical performance in the center and periphery of the field of view (FOV) and can have excellent optical characteristics.

math equation Example One n_G1, n_G2, n_G3 > 1 Satisfaction 2 0.7 < CA41 / CA11 < 1.2 0.927 3 2 < CT1 / CT3 < 5 3.173 4 0 < CT1 / CT4 < 1.5 0.913 5 0 < ET3 / CT3 < 1 0.455 6 G1F < 0 -21.323 7 CRA < 20 Satisfaction 8 3.5 < (TTL/DG1) 4.782 9 2 < TTL / EPD3 < 7 4.423 10 2 < CT_Max/CT_Min < 6 4.989 11 1< CA_Max/CA_Min <3 1.189 12 0.1 < ∑CG_Wide /TTL < 0.6 0.366 13 0.5 < DG1 / DG2 < 3 0.842 14 0.5 < DG2 / DG3 < 2 1.193 15 0 < CG2 / TTL < 0.2 0.013 16 3 < TTL/DG2 < 10 4.782 17 20 < |Vd4 - Vd5| < 70 63.262 18 15 < |V7 - V6| < 60 36.465 19 1.6 < n2 1.680 20 1 < L1R1 / L3R2 < 2.5 1.649 21 1 < L1R1 / L4R1 < 2.5 1.610 22 0 < L3R2 / L4R1 < 2 0.976 23 1 < L1R1 / L7R2 < 3 2.041 24 0 < Mode12_mG2 / TTL < 0.5 0.084 25 0 < Mode23_mG2 / TTL < 0.5 0.031 26 0 < Mode12_mG2 / DG2 < 1 0.402 27 0 < Mode23_mG3 / DG3 < 0.5 0.176 28 0 <(CT1/ET1) / (CT3/ET3) < 1 0.355 29 0.5 < (CT1/ET1)/ (CT7/ET7) < 1.5 0.961 30 1< Mode1 (DG12 / DG23) < 5 2.315

math equation Example 31 0< Mode3 (DG12 / DG23) < 0.7 0.578 32 0.5 < TD2/TTL < 1 0.737 33 0.7 < TD1 / TD2 < 1.5 1.156 34 12<TD3<TD2<TD1<20 Satisfaction 35 0.1 < BFL1/TTL < 1 0.258 36 2 < BFL3 / BFL1 < 4 2.847 37 1.5 < TD3 /BFL3 < 3 2.066 38 2 < Mode_CG_Max / Mode_CG_Min < 8 4.695 39 1 < BFL1 < 5 2.653 40 30 < Aver_Abbe < 50 43.908 41 1.5 < Aver_Index < 1.8 1.593 42 2 < │ G1F/G2F │ < 4 3.079 43 1 < M2F / M1F < 10 1.369 44 2 < M2F / EPD2 < 7 2.949 45 0.1 < M1F / EPD1 < 3 2.402 46 M1F < M2F < M3F Satisfaction 47 0 <TTL/M2F<2 1.702 48 0.1 <TTL/M1F<5 2.330 49 1 < CA_Max / ImgH < 3 2.183 50 5 <TTL/ImgH<12 9.524 51 1 <BFL2/ImgH<3 2.453 52 2 < BFL3/ImgH < 4 2.997 53 1 < EPD1 < EPD2 < EPD3 < 7 Satisfaction 54 0 < Max_Distortion < 3 1.200 55 8 < FOV3 < FOV2 < FOV1 <45 Satisfaction

The optical system and camera module according to the embodiment may satisfy at least one or two of Equations 1 to 30 and/or Equations 31 to 55, or may satisfy all of the equations.

Figure 13 is a diagram showing a camera module according to an embodiment applied to a mobile terminal. Referring to FIG. 13, the mobile terminal 1 may include the camera module 10 disclosed in the embodiment on the rear side. As another example, the mobile terminal 1 may include the camera module disclosed in the embodiment on the front. The camera module 10 may include an image capturing function. Additionally, the camera module 10 may include at least one of an auto focus, zoom function, and OIS function.

The camera module 10 can process image frames of still images or videos obtained by the image sensor 300 in shooting mode or video call mode. The processed image frame may be displayed on a display unit (not shown) of the mobile terminal 1 and may be stored in a memory (not shown). In addition, although not shown in the drawing, the camera module may be further disposed on the front of the mobile terminal 1. For example, the camera module 10 may include a first camera module 10A and a second camera module 10B. At this time, at least one of the first camera module 10A and the second camera module 10B may include the optical system 1000 described above. Accordingly, the camera module 10 can have a slim structure and can photograph subjects at various magnifications.

The mobile terminal 1 may further include an autofocus device 31. The autofocus device 31 may include an autofocus function using a laser. The autofocus device 31 can be mainly used in conditions where the autofocus function using the image of the camera module 10 is deteriorated, for example, at a distance of 10 m or less or in a dark environment. The autofocus device 31 may include a light emitting unit including a vertical cavity surface emitting laser (VCSEL) semiconductor device, and a light receiving unit such as a photo diode that converts light energy into electrical energy.

The mobile terminal 1 may further include a flash module 33. The flash module 33 may include a light emitting device inside that emits light. The flash module 33 may emit light in the visible light wavelength band. For example, the flash module 33 may emit white light or light of a color similar to white. However, the embodiment is not limited thereto, and the flash module 33 may emit light of various colors. The flash module 33 can be operated by operating a camera of a mobile terminal or by user control.

The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention. Although the above description focuses on the examples, this is only an example and does not limit the present invention, and those skilled in the art will be able to You will see that various variations and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

1000: Optics
100: Lenses
101-108: 1st to 8th lenses
300: Image sensor
400: Reflection member
500: optical filter

Claims (20)

It is arranged along the optical axis from the object side to the sensor side, and includes first to third lens groups each including at least one lens,
The first lens group and the third lens group have negative power,
The second lens group has positive power,
The position of the first lens group is fixed,
The second and third lens groups have lenses smaller than the number of lenses of the first lens group and are movable in the direction of the optical axis,
The optical system having the first to third lens groups has magnification according to at least three modes according to the movement of each of the second lens group and the third lens group,
At least one of the second and third lens groups has a lens with the thickest center thickness,
Among the lenses of the first lens group, the optical axis distance between the surface closest to the object and the image surface of the image sensor is TTL,
When operating at the highest magnification among the operation modes, the entrance pupil diameter of the optical system is EPD3.
Equation: 2 < TTL / EPD3 < 7
An optical system that satisfies . According to claim 1,
An optical system in which an optical axis spacing between the image sensor and a lens closest to the image sensor in the third lens group varies depending on the operation mode. According to claim 1,
An optical system in which the optical axis distance between the object-side surface of the lens closest to the object in the first lens group and the sensor-side surface of the lens closest to the image sensor in the third lens group varies depending on the operation mode. According to any one of claims 1 to 3,
The operating mode includes wide mode,
The wide mode is Mode1,
In the wide mode, the optical axis spacing between the first and second lens groups is DG12, and the optical axis spacing between the second and third lens groups is DG23,
Equation: 1< Mode1 (DG12 / DG23) < 5
An optical system that satisfies . According to any one of claims 1 to 3,
The operating mode includes tele mode,
The tele mode is Mode3,
In the tele mode, the optical axis spacing between the first and second lens groups is DG12, and the optical axis spacing between the second and third lens groups is DG23,
Equation: 0 < Mode3 (DG12 / DG23) < 0.7
An optical system that satisfies . According to any one of claims 1 to 3,
The maximum spacing between adjacent lenses according to the operation mode is Mode_CG_Max,
The minimum gap between adjacent lenses according to the operation mode is Mode_CG_Min,
Equation: 2 < Mode_CG_Max / Mode_CG_Min < 8
An optical system that satisfies . According to any one of claims 1 to 3,
The number of lenses in the first lens group is 3,
An optical system wherein the absolute value of the focal lengths of the first and third lens groups is greater than the focal length of the second lens group. According to clause 7,
The optical system includes a wide mode with a first effective focal length (EFL1), a middle mode with a second effective focal length (EFL2), and a tele mode with a third effective focal length (EFL3),
Equation: EFL1 < ELF2 < EFL3
An optical system that satisfies . According to clause 8,
The angle of view in the wide mode is FOV1, the angle of view in the middle mode is FOV2, and the angle of view in the tele mode is FOV3,
Equation: 8 degrees < FOV3 < FOV2 < FOV1 < 45 degrees
An optical system that satisfies . According to any one of claims 1 to 3,
The second lens group is an optical system including an object-side lens having an aspherical surface made of glass and having both sides convex, and a sensor-side lens having an aspherical surface made of plastic. a first lens group having first to third lenses;
a second lens group having fourth and fifth lenses;
a third lens group having sixth and seventh lenses,
The first lens group, the second lens group, and the third lens group are arranged in the optical axis direction from the object side to the sensor side,
The first lens has positive refractive power and has a convex shape on the object side,
The third lens has negative refractive power and has a concave shape on both sides,
The fourth lens has positive refractive power and has a convex shape on both sides,
The seventh lens has negative refractive power,
The second lens group and the third lens group are moved in the optical axis direction,
An optical system in which the optical axis spacing between the seventh lens and the image sensor varies depending on the operation mode. According to claim 11,
The first lens group has negative refractive power,
The first lens has a meniscus shape convex toward the object,
The second lens has a meniscus shape convex toward the sensor,
The second and fifth lenses have negative refractive power. The method of claim 11 or 12,
An optical system in which the fourth lens and the seventh lens have a refractive index of less than 1.6. The method of claim 11 or 12,
The fourth lens is made of glass and is an aspherical lens,
The first, second, third, fifth, sixth, and seventh lenses are made of plastic and are aspherical lenses. The method of claim 11 or 12,
The first lens is an optical system in which the maximum length in the first direction orthogonal to the optical axis is different from the maximum length in the second direction. According to claim 15,
The maximum length of the first lens in the first and second directions is the largest among the lenses,
The difference between the center thickness and edge thickness of the fifth lens is 0.9 or more,
An optical system wherein the difference between the center thickness and the edge thickness of the sixth lens is 0.9 or more. The method of claim 11 or 12,
An optical system wherein the optical axis gap between the first and second lens groups and the optical axis gap between the second and third lens groups are at least 0.2 mm or more and at most 8 mm or less. The method of claim 11 or 12,
Vd4 is the Abbe number of the fourth lens and Vd5 is the Abbe number of the fifth lens,
Vd6 is the Abbe number of the 6th lens and Vd7 is the Abbe number of the 7th lens,
Math equation:
20 < |Vd4 - Vd5| < 70
15 < |Vd7 - Vd6| < 60
An optical system that satisfies . The method of claim 11 or 12,
The optical axis distance from the center of the object-side surface of the fourth lens to the center of the sensor-side surface of the fifth lens is DG2,
The optical axis distance between the object side of the first lens and the image surface of the image sensor is TTL,
Equation: 3 < TTL/DG2 < 10
An optical system that satisfies . In a camera module including an optical system and a driving member,
The optical system includes the optical system according to claim 1 or 11,
The driving member is a camera module that drives each position of the second and third lens groups in the optical axis direction.

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