KR20220066697A - Optical system and camera module - Google Patents

Abstract

An optical system disclosed in an embodiment of the invention comprises: a first lens group having multiple lenses; an image sensor; a second lens group having multiple lenses between the first lens group and the image sensor and having a variable distance from the first lens group; and an optical filter between the image sensor and the second lens group, wherein the first lens group includes a first lens having positive refractive power, a first surface on an object side being convex, and a second surface on an image side being concave; a second lens having negative refractive power, a third surface on the object side being concave, and a fourth surface on the image side being concave; and a third lens having positive refractive power, a fifth surface on the object side being convex, and a sixth surface on the image side being convex, wherein the refractive power of the first lens group is positive refractive power, and the refractive power of the second lens group is negative refractive power. According to the present invention, the optical system can reduce the size of a camera module by moving the lens groups within the camera module to achieve focusing, thereby providing a slim AF optical system.

Description

Optical system and camera module having the same

An embodiment of the invention relates to an optical system and a camera module having the same.

An embodiment of the invention relates to a camera module that can be mounted on a moving object.

The camera module captures an object and stores it as an image or video, and is installed in various applications. In particular, the camera module is produced in a very small size and is applied to not only portable devices such as smartphones, tablet PCs, and laptops, but also drones and vehicles to provide 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. In this case, the camera module may perform an autofocus (AF) function of aligning the focal lengths of the lenses by automatically adjusting the distance between the image sensor and the imaging lens, and a distant object through a zoom lens A zooming function of zooming up or zooming out may be performed by increasing or decreasing the magnification of . In addition, the camera module employs an image stabilization (IS) technology to correct or prevent image stabilization due to an unstable fixing device or a camera movement caused by a user's movement.

The most important element for this camera module to obtain an image is an imaging lens that forms an image. Recently, interest in high performance such as high image quality and high resolution is increasing, and research on an optical system including a plurality of lenses is being conducted in order to realize this.

For example, research using a plurality of imaging lenses having positive (+) and/or negative (-) refractive power to implement a high-performance optical system is being conducted. However, when a plurality of lenses are included, the entire optical system may increase, and it is difficult to derive excellent optical and aberration characteristics.

An embodiment of the present invention may provide an optical system and a camera module for adjusting a focus by moving the object-side first lens group or the image-side second lens group.

According to an embodiment of the present invention, the focus is adjusted by moving the image-side second lens group in the optical axis direction based on the object-side first lens group or by moving the object-side first lens group in the optical axis direction with respect to the image-side second lens group. It is possible to provide an optical system and a camera module.

An embodiment of the present invention may provide an optical system and a camera module in which a first lens group having a plurality of lenses and having a variable position and a second lens group having a plurality of lenses and having a fixed position are aligned with an optical axis.

An embodiment of the present invention may provide an optical system and a camera module in which a first lens group having a plurality of lenses and having a fixed position and a second lens group having a plurality of lenses and having a variable position are aligned along an optical axis.

An embodiment of the present invention may provide a camera module and a moving body having the same.

An optical system according to an embodiment of the present invention includes a first lens group having a plurality of lenses; image sensor; a second lens group having a plurality of lenses between the first lens group and the image sensor and having a variable distance from the first lens group; and an optical filter between the image sensor and the second lens group, wherein the first lens group includes: a first lens having positive refractive power and having a convex object-side first surface and a concave image-side second surface; a second lens having negative refractive power and having a third object-side surface concave and an image-side fourth surface concave; and a third lens having positive refractive power, a fifth surface on the object side is convex, and a sixth surface on the image side is convex, wherein the refractive power of the first lens group has positive refractive power, and the refractive power of the second lens group is negative refractive power can have

According to an embodiment of the present invention, the second lens group may include: a fourth lens having negative refractive power, a seventh surface on the object side being concave and an eighth surface on the image side concave; and a fifth lens having positive refractive power, the object-side ninth surface being convex, and the image-side tenth surface convex.

According to an embodiment of the present invention, the effective diameter of the first surface and the second surface of the first lens may be the largest among the second to fifth lenses.

According to an embodiment of the present invention, the optical system satisfies 10 < EFL < 35, and the EFL may represent an effective focal length (mm) of the optical system.

According to an embodiment of the present invention, the optical system satisfies 1.5 < BFL/ImgH < 5, and the back focus length (BFL) is the image side tenth surface of the fifth lens and the second lens group when the second lens group is in an initial state. The distance in the optical axis direction between the image sensors, and the ImgH may be 1/2 of the diagonal length of the effective area of the image sensor.

According to an embodiment of the present invention, the optical system satisfies 0.30 < BFL/EFL < 0.75, and the BFL (Back focus length) is equal to the image-side tenth surface of the fifth lens when the second lens group is in an initial state. An optical axis direction distance between the image sensors, and the EFL may be an effective focal length of the optical system.

According to an embodiment of the invention, the optical system satisfies 1.8 < TTL/BFL < 2.7, and the total track length (TTL) is a distance in the optical axis direction between the first surface of the first lens and the image sensor 190 , the back focus length (BFL) may be a distance in the optical axis direction between the image sensor 190 and the image-side tenth surface of the fifth lens.

A camera module according to an embodiment of the present invention includes: a substrate; an image sensor disposed on the substrate; a first lens group including a plurality of lenses on the image sensor; a second lens group including a plurality of lenses between the first lens group and the image sensor; a first lens holder supporting the first lens group; an optical filter between the image sensor and the second lens group; a second lens holder supporting the second lens group in the first lens holder; and a driving unit for moving the second lens holder in an optical axis direction, wherein the first lens group includes: a first lens having positive refractive power, a first object-side surface is convex, and an image-side second surface is concave; a second lens having negative refractive power and having a third object-side surface concave and an image-side fourth surface concave; and a third lens having positive refractive power, a fifth surface on the object side is convex, and a sixth surface on the image side is convex, wherein the refractive power of the first lens group has positive refractive power, and the refractive power of the second lens group is negative refractive power can have

According to an embodiment of the present invention, the second lens group may include: a fourth lens having negative refractive power, a seventh surface on the object side being concave and an eighth surface on the image side concave; and a fifth lens having positive refractive power, a ninth surface on the object side is convex and a tenth surface on the image side is convex, wherein the effective diameters of the first surface and the second surface of the first lens are the second to fifth lenses. may be the largest among them.

According to an embodiment of the present invention, stoppers for limiting movement of the second lens holder may be respectively included on upper and lower portions of the first lens holder, and each of the stoppers may overlap the second lens holder in a vertical direction. .

According to an embodiment of the present invention, the driving unit may include an actuator having a movable member disposed outside the second lens holder and a fixing part facing the movable member inside the first lens holder.

According to an embodiment of the present invention, the first lens group may include three or less lenses, and the second lens group may include two to four lenses.

According to an embodiment of the present invention, the TTL in the camera module is in the range of 10 mm to 25 mm, the effective focal length is in the range of 10 mm to 35 mm, and the movement amount of the second lens group may be 2 mm or less.

According to an embodiment of the present invention, the Abbe numbers of the second and fifth lenses may be lower than the Abbe numbers of the first, third, and fourth lenses, and the Abbe numbers of the first, third, and fourth lenses may be 50 or more.

According to an embodiment of the present invention, the size of the camera module can be reduced by focusing by moving some lens groups in the camera module.

According to an embodiment of the present invention, without moving the lens(s) close to the subject, by moving the lenses close to the image side to focus, it is possible to reduce the movement space of the lens.

According to an embodiment of the present invention, it is possible to provide a slim AF optical system.

According to an embodiment of the invention, a high-resolution camera module can be implemented.

1 is an example of optical systems of a camera module according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating an example in which positions of some lens groups are moved in the optical system of FIG. 1 .
FIG. 3 is a view showing an example in which a reflective member is disposed on the incident side of the optical system of FIG. 1 .
4 is a view showing an example of an optical system in the camera module according to the second embodiment of the present invention.
5 is an example of a side cross-section of a camera module having an optical system according to an embodiment of the present invention.
6 is an example of a mobile terminal having a camera module according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The technical spirit of the present invention is not limited to some of the embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of the components between the embodiments are selectively combined , can be used as a substitute. In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be generally understood by those of ordinary skill in the art to which the present invention belongs, unless specifically defined and described explicitly. It may be interpreted as a meaning, and generally used terms such as terms defined in advance may be interpreted in consideration of the contextual meaning of the related art.

In addition, the terminology used in the embodiments of the present invention is for describing the embodiments and is not intended to limit the present invention. In this specification, the singular form may also include the plural form unless otherwise specified in the phrase, and when it is described as "at least one (or more than one) of A and (and) B and C", it is combined as A, B, C It can contain one or more of all possible combinations. In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only used to distinguish the component from other components, and the essence, order, or order of the component is not determined by the term. And, when it is described that a component is 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also with the component It may also include a case of 'connected', 'coupled' or 'connected' due to another element between the other elements. In addition, when it is described as being formed or disposed on "above (above) or below (below)" of each component, the top (above) or bottom (below) is one as well as when two components are in direct contact with each other. Also includes a case in which another component as described above is formed or disposed between two components. In addition, when expressed as “up (up) or down (down)”, it may include not only the upward direction but also the meaning of the downward direction based on one component.

In addition, several embodiments described below may be combined with each other, unless it is specifically stated that they cannot be combined with each other. In addition, the description of other embodiments may be applied to parts omitted from the description of any one of several embodiments unless otherwise specified.

In the description of the invention, the first lens means the lens closest to the object side, and the last lens means the lens closest to the image side (or sensor surface). In the description of the invention, all units for the radius, thickness/distance, TTL, etc. of the lens are mm unless otherwise specified. In the present specification, the shape of the lens is shown based on the optical axis of the lens. For example, the meaning that the object side of the lens is convex means that the vicinity of the optical axis is convex on the object side of the lens, but does not mean that the vicinity of the optical axis is convex. Accordingly, even when it is described that the object side of the lens is convex, the portion around the optical axis on the object side of the lens may be concave. In the present specification, it should be noted that the thickness and radius of curvature of the lens are measured based on the optical axis of the lens.

In the description of the invention, the first lens means the lens closest to the object side, and the last lens means the lens closest to the image side (or sensor surface). The last lens may include a lens adjacent to the image sensor. Unless otherwise specified in the description of the invention, the units for the radius, thickness/distance, TTL, etc. of the lens are all mm, and it is to be noted that it is measured based on the optical axis. In the present specification, the shape of the lens is shown based on the optical axis of the lens. For example, the meaning that the object side of the lens is convex or concave means that the vicinity of the optical axis is convex or concave on the object side of the lens, but does not mean that the vicinity of the optical axis is convex or concave. Accordingly, even when it is described that the object side of the lens is convex, the portion around the optical axis on the object side of the lens may be concave, and vice versa. In addition, “object-side surface” may mean a surface of the lens that faces the object side with respect to the optical axis, and “image-side surface” may mean a surface of the lens that faces the imaging surface with respect to the optical axis. The optical system according to an embodiment of the present invention may include a lens made of a glass material and/or a lens made of a plastic material.

1 is an example of optical systems of a camera module according to an embodiment of the present invention, FIG. 2 is a diagram for explaining an example in which the distance between lens groups is increased in the optical system of FIG. 1, and FIG. 3 is an incident side in the optical system of FIG. It is a view showing an example in which the reflective member is disposed.

1 and 2 , an optical system according to an embodiment of the present invention may include four or more lenses or five or more lens optical systems. The camera module may include a first lens group 110 having at least a plurality of lenses 111 , 113 , and 115 on the object side, and a second lens group 120 having a plurality of lenses 1117 and 119 on the image side.

The first lens group 110 may be disposed between the object and the second lens group 120 , and the second lens group 120 may be disposed between the first lens group 110 and the image sensor 190 . have. The first lens group 110 may include two or more or three or less lenses 111 , 115 , and 117 , and may be less than or equal to the number of lenses of the second lens group 120 . For example, the number of lenses in the second lens group 120 may be greater or less than the number of lenses in the first lens group 110 . The first lens group 110 may be stacked with 2 to 3 lenses, and the second lens group 120 may be stacked with 2 to 5 lenses or 2 to 4 lenses. The lenses 111 , 113 , and 115 of the first lens group 110 may be solid lenses. The lenses 117 and 119 of the second lens group 120 may be solid lenses.

Since the focal length of the first lens group 110 and the focal length of the second lens group 120 are opposite to each other, the amount of curvature on the image sensor 190 may complement each other. In addition, since the focal length of the second lens group 120 is short, the amount of curvature is small even when the position of the subject changes, and a movement amount of about 1.7mm±0.3mm may be required for 3cm focus. In the comparative example, when the camera module is a high-point zoom, the focal length is long, so a large amount of curvature may be generated according to the position of the subject, and a decrease in the modulation transfer function (MTF) may be increased. For example, a movement amount of about 430 μm is required for a focus of 70 cm, but there is a problem in that the amount of movement increases to 16 mm for a focus of 3 cm. As another example, the focus of the optical system may be adjusted by fixing the position of the second lens group 120 and moving the position of the first lens group 110 in the optical axis direction. As another example, when divided into three lens groups, each lens group has at least one lens, and only the lens group adjacent to the image sensor 190 may be moved to adjust the focal length.

The first lens group 110 may include a first lens 111 , a second lens 113 , and a third lens 115 aligned along an optical axis from the object side toward the image side. The first to third lenses 111 , 113 , and 115 may be made of a solid lens, for example, a glass material or a plastic material. The second lens group 120 includes a fourth lens 117 and a fifth lens 119 aligned along an optical axis, and may be made of glass or plastic. At least one or all of the lenses 111 , 113 , 115 , 117 , and 119 may include an aspherical surface on an incident-side surface. At least one or all of the lenses 111 , 113 , 115 , 117 , and 119 may include an aspherical surface on the exit side.

The lenses 111 , 113 , 115 , 117 , and 119 may all be made of a plastic material. As another example, at least one of the lenses 111 , 113 , 115 , 117 and 119 may be made of glass, and the rest may be made of plastic. As another example, at least one of the lenses 111 , 113 , 115 , 117 and 119 may be made of a plastic material, and the rest may be made of a glass material.

The optical system according to the present invention may include four or more lenses 111,113,115,117,119, and a first lens 111, a second lens 113, a third lens 115, and a third sequentially arranged from the object side to the image side. It may include a fourth lens 117 and a fifth lens 119 . The camera module may include an optical filter 192 and an image sensor 190 in an image direction of the second lens group 120 . Such an optical system and a camera module having the same may be applied to a mobile device such as a vehicle or a portable terminal.

The optical system may include a diaphragm ST for adjusting the amount of incident light. The diaphragm ST may be disposed between the lenses 111 , 113 , and 115 of the first lens group 110 , or disposed on the periphery of any one of the lenses of the first lens group 110 on the incident side or the exit side. can For example, the diaphragm ST may be disposed around the exit side surface of the first lens 111 .

The optical system has a function of automatically focusing on an object or subject in order to implement the AF function. In the general AF function, the entire lens moves toward the subject while the position of the subject moves from the far side to the near side. Accordingly, a larger space for mounting the camera module is required. In an embodiment of the present invention, the AF function may be adjusted by moving any one of the first lens group 110 and the second lens group 120 .

An embodiment of the present invention may provide an optical system capable of focusing by moving only some lenses without moving a lens close to the subject when the position of the subject moves from the near side to the far side. That is, by providing an optical system for focusing by moving only the image side lens group without moving the object side lens group, it is possible to relatively suppress an increase in space or a moving distance. Accordingly, it is possible to focus by moving any one of the plurality of lens groups.

1 and 2 , the first lens group 110 may be fixed in position, and the second lens group 120 may be moved (M1) in the optical axis Lz direction. That is, the second lens group 120 may move toward the object side or the image side along the optical axis Lz. The second lens group 120 may move toward the first lens group 110 along the optical axis Lz or toward the image sensor 190 . The first lens group 110 and the second lens group 120 may be focused by the movement M1 of the second lens group 120 .

Since the position of the first lens 111 closest to the object side is fixed, the distance between the image sensor 190 and the first lens 111 may be constant. The second lens 113 and the third lens 115 may be fixedly positioned between the first lens 111 and the fourth lens 117 .

At least one or both of the fourth and fifth lenses 117 and 119 disposed between the third lens 115 and the image sensor 190 moves toward the first lens 111 or toward the image sensor 190 . can be moved Accordingly, the distances D1 and D2 between the object-side surfaces of the fourth and fifth lenses 117 and 119 and the first lens 111 or between the third lens 115 may vary, and the second Distances BFL1 and BFL2 between the upper surface of the lens group 120 and the image sensor 190 may be variable, and the BFL1 may be 9 mm or less, for example, in a range of 7 mm to 9 mm. By moving the fourth and fifth lenses 117 and 119 , the light incident through the first lens group 110 may be adjusted to be focused on the image sensor 190 . When the distance to the object is changed, the second lens group 120 moves to perform the AF function.

Either one of the first lens group 110 and the second lens group 120 may be moved in a direction orthogonal to an optical axis for an OIS (Optical Image Stabilizer) function. The camera module may include a driving member for moving the optical system, and the driving member may be an actuator or a piezoelectric element for an Auto Focus (AF) function and/or an Optical Image Stabilizer (OIS) function.

Here, the effective focal length of the optical system may be changed. The effective focal length (EFL) of the optical system of the present invention may be in the range of 35 mm or less, for example, 10 mm to 35 mm or 13 mm to 23 mm, and the amount of change in the effective focal length by the second lens group 120 may be 30% or less, , for example 4 mm or less or in the range of 1 mm to 4 mm. Here, the TTL (Total Top Length) of the lens optical system may be 35 mm or less, for example, in the range of 10 mm to 25 mm or in the range of 13 mm to 23 mm.

Here, the EFL of the first lens group 110 may be 7.5 mm or less, for example, in the range of 5 mm to 7.5 mm. When the EFL of the second lens group 110 is an absolute value, the EFL of the first lens group 110 may be less than or equal to the EFL of the first lens group 110 . The EFL of the second lens group 110 may be -7.5 mm or less, for example, in the range of -5 mm to -7.5 mm. In this case, a curvature of 8 μm or less may occur in a near object, for example, a 3 cm subject. Since the focal length of the first lens group 110 and the focal length of the second lens group 120 are opposite to each other, the amount of curvature may be complemented with each other.

The F number of the optical system may be 4 or less, for example, in the range of 2.5 to 4 or in the range of 3 to 3.6. In the optical system, the distance to the object is at least 30 mm or more, for example, 35 mm, and may be at most infinity. Here, the maximum/minimum brightness value of the object distance may be 80% or more of the F number.

In the optical system, the focal length of the first lens group 110 may be 5 mm or more, for example, in the range of 5 mm to 7.5 mm, and the focal length of the second lens group 120 is -7.5 mm or less, for example, - It may be in the range of 5 mm to -7.5 mm, and may be greater than the focal length of the first lens group 110 in absolute value. Since the effective focal lengths of the first lens group 110 and the second lens group 120 have opposite values and thus complement each other, the amount of curvature in the object can be reduced even when the position of the subject changes.

In absolute values, the difference between the focal lengths of the first lens group 110 and the second lens group 120 may be 0.5 mm or less, for example, in the range of 0.02 mm to 0.12 mm. In absolute values, the ratio of the focal length of the first lens group 110 to the focal length of the second lens group 120 may be less than or equal to 1.2, for example, in the range of 0.8 to 1.2.

In addition, the refractive power of the second lens group 120 may have a negative refractive power, and may have a power different from that of the first lens group 110 . Accordingly, it is possible to focus without increasing the TTL by the second lens group 120 . In the optical system, a lens having a maximum effective diameter may be disposed in a fixed group or a driving group. The lens having the maximum effective diameter may be in the range of 0.8 times to 1.2 times the size of the image sensor.

The first to sixth lenses 111 , 113 , 115 , 117 and 119 may be sequentially disposed along the optical axis Lz of the optical system. The light corresponding to the image information of the object is the first lens 111 , the second lens 113 , the third lens 115 , the fourth lens 117 , the fifth lens 119 , and the sixth lens 125 . ) and passing through the filter 192 may be incident on the image sensor 190 .

Each of the first to sixth lenses 111 , 113 , 115 , 117 and 119 may include an effective area and an ineffective area. The effective area may be an area through which light incident on each lens passes. That is, the effective region may be a region in which incident light is refracted to realize optical properties. The ineffective area may be disposed around the effective area. The ineffective area may be an area to which the light is not incident. That is, the ineffective region may be a region independent of the optical characteristic. Also, the ineffective region may be a region fixed to a lens holder or a barrel (not shown) for accommodating lenses.

1 and 2 , the first lens 111 may have positive (+) refractive power. The refractive power of the first lens 111 may be 0.15 or less. The first lens 111 may include a glass material or a plastic material. The first lens 111 may include a first surface S1 defined as an object-side surface and a second surface S2 defined as an image-side surface. The first surface S1 may be an incident surface, and the second surface S2 may be an exit surface. On the optical axis, the first surface S1 may be convex and the second surface S2 may be concave. That is, the first lens 111 may have a meniscus shape convex toward the object. At least one or both of the first surface S1 and the second surface S2 may be aspherical.

The effective radius of the first lens 111 may be greater than the effective radius of the second to fifth lenses 113 , 115 , 117 and 119 with respect to the optical axis. Accordingly, the amount of ambient light may be improved.

The thickness of the first lens 111 on the optical axis Lz of the optical system, ie, the central thickness, may be thicker than the thickness of the second to fourth lenses 113, 115, and 117, and is 1.5 mm or more, for example, 1.5 mm to 2.5 mm. can be The first lens 111 may have a relatively thick thickness and a large effective diameter, and may refract the amount of incident light to be condensed into the second lens 113 .

The second lens 113 may have a negative refractive power. The refractive power of the second lens 113 may be -0.23 or more. The second lens 113 may include a plastic material. The second lens 113 may include a third surface S3 defined as an object-side surface and a fourth surface S4 defined as an image-side surface. The third surface S3 may be an incident surface, and the fourth surface S4 may be an exit surface. The third surface S3 may be concave upward and the fourth surface S4 may be concave toward the object. At least one or both of the third surface S3 and the fourth surface S4 may be aspherical.

The thickness of the second lens 113 on the optical axis Lz of the optical system may be smaller than the thickness of the first and third lenses 111 and 115, and may be 0.6 mm or less, for example, 0.1 mm to 0.6 mm. The second lens 113 may be provided to have the thinnest thickness among the lenses.

The third lens 115 may have positive (+) refractive power. A refractive power value of the third lens 115 may be greater than a refractive power value of the first lens 111 . The third lens 115 may include a glass or plastic material. The third lens 115 may include a fifth surface S5 defined as an object-side surface and a sixth surface S6 defined as an image-side surface. The fifth surface S5 may be an incident surface, and the sixth surface S6 may be an exit surface. The fifth surface S5 may be convex toward the object and the sixth surface S6 may be convex upward. At least one or both of the fifth surface S5 and the sixth surface S6 may be aspherical.

The thickness of the third lens 115 on the optical axis Lz of the optical system may be greater than the thickness of the second and fourth lenses 111 and 115, and may be 1 mm or more, for example, 1 mm to 1.7 mm. The third lens 115 may be thinner than the thickness of the first lens 111 , such that a thickness difference between the two lenses 111 and 113 may be 1 mm or less. The third lens 115 receives the light diffused by the concave fourth surface S4 of the second lens 113 and receives the incident light from the convex fifth and sixth surfaces S5 and S6. It can be refracted so that light is collected through it.

The fourth lens 117 may have a negative refractive power. The fourth lens 117 may include a glass or plastic material. The fourth lens 117 may include a seventh surface S7 defined as an object-side surface and an eighth surface S8 defined as an image-side surface. The seventh surface S7 may be an incident surface, and the eighth surface S8 may be an exit surface. The seventh surface S7 may be concave upward, and the eighth surface S8 may be concave toward the object. At least one or both of the seventh surface S7 and the eighth surface S8 may be aspherical.

The thickness of the fourth lens 117 on the optical axis Lz of the optical system may be smaller than the thickness of the third and fifth lenses 115 and 119, and may be 0.9 mm or less, for example, 0.1 mm to 0.9 mm. The fourth lens 117 may be thicker than the second lens 117 , and a thickness difference from the third lens 115 may be 0.7 mm or more. The fourth lens 117 receives the light collected by the convex sixth surface S6 of the third lens 115 and receives the incident light through the concave seventh and eighth surfaces S7 and S8. It can be refracted so that it diffuses through it.

The fifth lens 119 may have positive (+) refractive power. The refractive power value of the fifth lens 119 may be smaller than the refractive power value of the first lens 111 . The fifth lens 119 may include a plastic material. The fifth lens 119 may include a ninth surface S9 defined as an object-side surface and a tenth surface S10 defined as an image-side surface. The ninth surface S9 may be an incident surface, and the tenth surface S10 may be an exit surface. The ninth surface S9 may be upwardly convex and the tenth surface S10 may be upwardly convex. At least one or both of the ninth surface S9 and the tenth surface S10 may be aspherical.

The thickness of the fifth lens 119 on the optical axis Lz of the optical system may be greater than the thickness of the fourth lens 117, and may be 0.8 mm or more, for example, 0.8 mm to 2 mm. The fifth lens 119 may have the same thickness as that of the first lens 111 or may have a thickness difference of 1 mm or less. The fifth lens 119 receives the light diffused by the concave eighth (S8) of the fourth lens 117, and forms a concave ninth surface (S9) and a convex tenth surface (S10) for the incident light. Through the image sensor 190, the light may be condensed.

Here, the distance between the first lens 111 and the second lens 113 on the optical axis may be the largest among the distances between the two adjacent lenses, and is 1.5 mm or more, for example, in the range of 1.5 mm to 3 mm, or 1.8 mm to 2.5 mm. The distance between the first lens 111 and the second lens 113 may be greater than the central thickness of the first lens 111, and may be 1.8 times or less of the central thickness of the first lens 111. For example, It may range from 0.8 times to 1.8 times.

The distance between the second lens 113 and the third lens 115 may be the smallest among the distances between the two adjacent lenses, and may be less than or equal to 0.05 mm, for example, in the range of 0.05 mm to 0.2 mm. The distance between the second lens 113 and the third lens 115 may be smaller than the thickness of the center of the second lens 113, and 20% or more of the thickness of the center of the second lens 113. For example, It may range from 20% to 40%.

The minimum distance between the third lens 115 and the fourth lens 117 may be the second smallest distance between two adjacent lenses, and may be 0.4 mm or less, for example, in the range of 0.05 mm to 0.4 mm. . A distance between the third lens 115 and the fourth lens 117 may be greater than a distance between the second lens 113 and the third lens 115 . The distance D1 between the third lens 115 and the fourth lens 117 may be 40% or less smaller than the thickness of the center of the third lens 115 , and the center of the third lens 115 may be 40% or less. It can range from 20% to 40% of the thickness. The distance D1 between the third lens 115 and the fourth lens 117 may vary, and may be greater than or equal to the thickness of the fifth lens 119 at the maximum distance D2.

The distance between the fourth lens 117 and the fifth lens 119 may be the second largest between the two adjacent lenses, and may be 0.2 mm or more, for example, 0.2 mm to 0.85 mm. A distance between the fourth lens 117 and the fifth lens 119 may be greater than a minimum distance between the third lens 115 and the fourth lens 117 . The distance between the fourth lens 117 and the fifth lens 119 may be 50% or less less than the central thickness of the fifth lens 119, and 30 of the central thickness of the fifth lens 119. % to 50%.

In the optical system, the focal length of the first lens 111 has a positive value, and may be 7 mm or more, for example, in the range of 7 mm to 13 mm. The focal length of the second lens 113 has a negative value, and may be -3 mm or less, for example, in the range of -3 mm to -7 mm. The focal length of the third lens 115 has a positive value and may be 5 mm or less, for example, 1 mm to 5 mm. The focal length of the fourth lens 117 has a negative value, and may be -1 mm or less, for example, -1 mm to -5.5 mm. The focal length of the fifth lens 119 has a positive value, and may be 10 mm or more, for example, 10 mm to 16 mm. When an absolute value is taken, the focal length of the fifth lens 119 may be the largest among the focal lengths of the lenses.

The optical filter 192 may be disposed between the image sensor 190 and the second lens group 120 or between the image sensor 190 and the fifth lens 119 . The optical filter 192 may be disposed closer to the image sensor 190 than the second lens group 120 and may be fixed. The movable second lens group 120 and the image sensor 190 may be provided without another lens (ie, a fixed lens), and an optical filter 192 and/or a cover glass may be disposed.

The optical filter 192 may include an optical filter such as an infrared filter. The optical filter 192 may pass light of a set wavelength band and filter light of a different wavelength band. The optical filter 192 may block radiant heat emitted from external light from being transmitted to the image sensor 190 . In addition, the optical filter 192 may transmit visible light and reflect infrared light.

4 , a cover glass may be further disposed between the optical filter 190 and the image sensor 190 . The cover glass is a transparent material, and may protect the image sensor 190 on the image sensor 190 .

The image sensor 190 may detect the light passing through the optical filter 192 . The image sensor 190 may include a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

Looking at the effective diameter in the optical system, the effective diameter of the first surface S1 of the first lens 111 may be 5 mm or more or may be in the range of 5 mm to 5.5 mm, and may be larger than the effective diameter of the second surface S2. have. The effective diameter of the second surface S2 may be less than 5 mm, for example, in the range of 4.5 mm to 4.99 mm.

The effective diameter of the third surface S3 of the second lens 113 is smaller than the effective diameter of the first surface S1, and may be 4 mm or less or in the range of 4.5 mm to 5 mm, and the effective diameter of the fourth surface S4 may be equal to or greater than The effective diameter of the fourth surface S4 may be 4 mm or less, for example, in the range of 4.5 mm to 4 mm.

Effective diameters of the fifth and sixth surfaces S5 and S6 of the third lens 115 may be greater than the effective diameters of the third and fourth surfaces S3 and S4 of the second lens 113 , and the fifth surface S5 ) may be equal to or larger than the effective diameter of the sixth surface S6, and may be in the range of 4.2 mm or less, for example, 3.7 mm to 4.2 mm, and the effective diameter of the sixth surface S7 is 4.17 mm or less, for example, 3.7 mm or less. to 4.17 mm. The effective diameters of the seventh and eighth surfaces S5 and S6 of the fourth lens 117 may be smaller than the effective diameters of the fifth and sixth surfaces S7 and S8 of the third lens 115, and the seventh surface S7 ) may be equal to or larger than the effective diameter of the eighth surface S8, and may be in the range of 3.3 mm or less, for example, 2.9 mm to 3.1 mm, and the effective diameter of the eighth surface S8 is 3.27 mm or less, for example, 2.85 mm. to 3.27 mm.

The effective diameters of the ninth and tenth surfaces S9 and S10 of the fifth lens 119 may be larger than the effective diameters of the seventh and eighth surfaces S7 and S8 of the fourth lens 117, and the ninth surface S9 ) may be smaller than the effective diameter of the tenth surface S10, and may be in the range of 3.5 mm or less, for example, 2.8 mm to 3.5 mm, and the effective diameter of the tenth surface S10 is 4.2 mm or less, for example, 3.7 mm to It can be in the range of 4.2 mm. The tenth surface S10 may diffuse the light incident through the ninth surface S9 to uniformly irradiate the light from the center to the peripheral area of the image sensor 190 through the optical filter 192 . At least one or more of the first to fifth lenses 111, 113, 115, 117, and 119 may have a non-circular effective area. For example, the first axis direction orthogonal to the optical axis direction has a curvature first diameter, and The orthogonal second axis direction may have a shape having a constant distance. The at least one lens having the non-circular effective area may be disposed in the first lens group 110 or may be at least one of the first to third lenses.

Also, looking at the relative refractive index at 940 nm of the lens in the optical system, the first lens 111 has a lower refractive index than the refractive power of the second lens 113, and may be less than 1.6. The second lens 113 has a higher refractive index than that of the first lens 111 , and may be 1.6 or more. The third and fourth lenses 115 and 117 have a lower refractive index than that of the second lens 113 , and the difference between the two refractive indices may be at most 0.1 or less. The fifth lens 119 may have a higher refractive index than that of the fourth lens 117 , and may be 1.6 or more, for example, 1.65 or more. The fifth lens 119 has a higher refractive index than the refractive indices of the first to fourth lenses 111 , 113 , 115 , and 117 , and thus can effectively bend light.

Looking at the Abbe number in the d-line (587 nm) of the lens in the optical system, the Abbe number of the first lens 111 is greater than the Abbe number of the second lens 113, for example, 1.7 times or more. can The Abbe's number of the second lens 113 may be smaller than the Abbe's number of the first lens 111 and the third lens 115 , and may be, for example, 30 or less. The Abbe's number of the third lens 115 may be 50 or more. The Abbe's number of the first, third, and fourth lenses 111 , 115 , and 117 may be 50 or more, and may be equal to each other. The difference in Abbe's number between the third lens 115 and the fourth lens 117 may be no or less than 5. The Abbe's number of the fifth lens 119 may be smaller than the Abbe's number of the fourth lens 117 , and a difference from the Abbe's number of the second lens 113 may be 10 or less. The Abbe's number of the second lens 113 may be the smallest among the lenses of the optical system, and may be smaller than the Abbe's number of the second lens 113 and may be 25 or less.

Abbe's numbers in the lenses 111 , 113 , 115 , 117 , and 119 decrease when the refractive index of the lens increases. When the Abbe number is small, color dispersion is effective, and when the Abbe number is large, color dispersion can occur less. If the Abbe number of the lenses 111, 113, 115, 117, and 119 is high, chromatic aberration may be small and transparency may be improved.

In the optical system according to the first embodiment of the present invention, the half angle of view (HFOV) may be 12 degrees or less, for example, in the range of 5 degrees to 12 degrees. In the optical system, the distance from the center of the image sensor 190 to the end in the diagonal direction may be 3 mm or less, for example, 2 mm to 3 mm. In addition, the wavelength of the light beam used in the optical system may be in the range of 870 nm to 1000 nm. The MTF degradation may be 10% or less in a temperature range from a low temperature (eg -40 degrees C) to a high temperature (eg 85 degrees C).

In the optical system according to the first embodiment of the present invention, the material of the lens barrel or the lens holder supporting the lenses may be a metal material, for example, a metal having high heat dissipation characteristics. Accordingly, even when a lens made of a plastic material is used in the optical system, a decrease in heat dissipation efficiency can be prevented.

Table 1 shows the lens characteristics of the lens optical system according to the first embodiment.

first embodiment noodle # Radius Surface type Thickness/
Interval Index Abbe# Aperture first lens S1 6.490 ASP 1.80 1.52 56.0 5.387 S2 238.729 ASP 2.63 4.742 second lens S3 21.166 ASP 0.30 1.61 25.9 3.876 S4 3.947 ASP 0.10 3.859 third lens S5 3.177 ASP 0.140 1.53 56.0 3.936 S6 4.189 ASP 0.43 (variable) 3.9 4th lens S7 4.189 ASP 0.46 1.52 56.0 3.14 S8 5.231 ASP 0.74 2.983 5th lens S9 11.907 ASP 1.80 1.66 20.4 3.201 S10 31.732 ASP 0.10 4.0 filter S11 Infinity SPH 0.110 1.52 64.20 S12 Infinity SPH 0.452 image sensor Image Infinity SPH 0.000

In Table 1, the ASP indicates an aspherical surface, and in the items of each surface (S1-S10), the thickness indicates the thickness (unit, mm) of each lens on the optical axis, and the interval indicates the spacing between two lenses aligned on the optical axis. (unit, mm) is indicated. The thickness of S11 may be the thickness of the filter, and the thickness of the Image may be the thickness of the image sensor.

1 and 2 , the interval D1 between the third lens 115 and the fourth lens 117 may vary, for example, from the first interval D1 to the second interval D2. ), or may decrease from the second interval D2 to the first interval D1. For example, when the first interval D1 is in the range of 0.43 mm±0.05 mm (initial interval), the second lens group 120 is moved in the object side direction, and the second interval D2 is the maximum In the case of 2 mm±0.5 mm, the distance between the second lens group 120 and the first lens group 110 may be maximum. That is, since the distance between the second lens group 120 and the first lens group 110 increases or decreases, the focus can be achieved. The second lens group 120 may be moved along the optical axis in a range of 2 mm or less, for example, 0.05 mm to 1.8 mm.

Table 2 is a table showing the aspheric coefficients of the first to tenth surfaces S1-S10 of the first to fifth lenses in the first embodiment.

surface K A B C D S1 -2.895505107 0.002320605 0.000111739 5.89E-06 9.16E-07 S2 -90 0.002730788 0.0001854 4.05E-05 -4.84E-06 S3 66.63168515 0.00318383 -0.000769361 4.07E-05 -3.53E-05 S4 -7.765608274 0.004641438 0.00108648 -0.000411542 -8.84E-05 S5 -7.44123801 0.008892565 -0.001593729 0.000274329 -7.53E-07 S6 -4.299926202 -0.00680115 0.000739119 -0.000399757 0.000104179 S7 -4.299926202 -0.00680115 0.000739119 -0.000399757 0.000104179 S8 6.234523065 0.045426844 -0.023774688 0.009290163 -0.002411752 S9 34.05199116 -0.020440832 0.001686141 -0.002340219 0.001363265 S10 -71.47540422 -0.010070006 0.000401842 -0.000880661 0.000753831 surface E F G H J S1 5.01E-08 -1.03E-08 -2.39E-12 2.03E-10 -6.76E-12 S2 9.22E-07 -5.25E-08 2.88E-08 -7.15E-09 6.89E-10 S3 -9.42E-06 3.09E-06 3.18E-06 -1.18E-06 1.10E-07 S4 5.43E-06 3.30E-06 1.10E-06 -1.42E-09 -5.53E-08 S5 -2.63E-05 -3.87E-06 2.13E-06 4.13E-07 -1.07E-07 S6 2.63E-05 -1.20E-05 -2.43E-06 1.47E-06 -1.55E-07 S7 2.63E-05 -1.20E-05 -2.43E-06 1.47E-06 -1.55E-07 S8 0.000317692 -1.12E-05 -1.55E-06 -1.93E-07 6.56E-08 S9 -0.000454356 1.78E-05 3.69E-05 -1.19E-05 1.22E-06 S10 -0.000373954 0.000107058 -1.72E-05 1.34E-06 -3.34E-08

In Table 2, K is a conic constant, and A, B, C, D, ?? may mean an aspheric constant.

As the second lens group 120 is moved along the optical axis toward the object side or the image side, the distance between the fourth lens 117 and the third lens 115 can be changed, and the length or space of the optical system is increased. problem can be suppressed. Also, as the size of the image sensor 190 increases, it is possible to solve the problem that the length of the lens optical system increases according to the position of the object.

Referring to FIG. 3 , the optical system may further include a reflective member 101 on the incident side of the first lens group 110 . The reflective member 101 may change the path of the light by reflecting the light incident from the outside. The reflective member 101 may include a member for changing the path of light, such as a reflective mirror or a prism. For example, the reflective member 101 may reflect the incident light Lx in the direction of the optical axis Lz of the first and second lens groups 110 and 120 at right angles.

The reflective member 101 may be disposed closer to the object side than the plurality of lenses 111 , 113 , 115 , 117 and 119 . That is, the optical system may include a reflective member 101, a plurality of lenses 111,113,115,117,119, an optical filter 192 and an image sensor 190, which are sequentially disposed along the optical axis Lz from the object side to the image side. have. The reflective member 101 is rotated about the first axis (X) direction, rotated about the second axis (Y) direction, and/or the third axis (Z) direction or the optical axis by at least one or two or more driving units It can be rotated based on the (Lz) direction.

The optical system can be applied to a camera module that can reduce the thickness of the camera. The optical system may change light incident in a direction perpendicular to the surface of the moving object applied including the reflective member 101 in a direction parallel to the surface of the moving object. Accordingly, the optical system including the plurality of lenses may have a thinner thickness within the movable body, and thus the movable body may be provided with a thinner thickness.

4 is a diagram illustrating an example of an optical system according to a second embodiment. In the description of the second embodiment, the same parts as those of the first embodiment will be referred to with reference to the first embodiment, and duplicate description will be omitted.

Referring to FIG. 4 , the first lens group 110 may have a positive refractive power, and the second lens group 120 may have a negative refractive power. The first lens group 110 may include first to third lenses 111 , 113 , and 115 , and the second lens group 120 may include fourth and fifth lenses 117 and 119 .

The refractive power, surface shape, thickness and spacing on the optical axis, F-number, refractive index, half angle of view, etc. of the first to fifth lenses 111,113,115,117,119 will refer to the description of the first embodiment, and optionally in the second embodiment It can be applied, and the differences will be explained.

In the second embodiment, the distance between the first lens 111 and the second lens 113 may be the largest among the distances between the lenses in the optical system, and is 1.5 mm or more, for example, in the range of 1.5 mm to 3 mm, or It may range from 1.8 mm to 2.5 mm. The distance between the first lens 111 and the second lens 113 may be greater than the central thickness of the first lens 111, and is 1.1 times or more of the central thickness of the first lens 111. For example, It may range from 1.1 to 1.5 times.

The distance between the third lens 115 and the fourth lens 117, that is, the minimum distance D1, may be the third smallest among the distances between two adjacent lenses, and is 0.4 mm or less, for example, 0.30 mm to 0.4 mm. may be in the range of A distance between the third lens 115 and the fourth lens 117 may be greater than a distance between the second lens 113 and the third lens 115 . The distance D1 between the third lens 115 and the fourth lens 117 may be 35% or less smaller than the thickness of the center of the third lens 115 , and the center of the third lens 115 may be less than or equal to 35%. It may range from 15% to 35% of the thickness. When the distance between the third lens 115 and the fourth lens 117 is maximum due to the movement of the second lens group 120 , the thickness of the fifth lens 119 may be greater than that of the fifth lens 119 .

The distance between the fourth lens 117 and the fifth lens 119 may be the second largest among the gaps between two adjacent lenses, and may be 0.50 mm or more, for example, 0.50 mm to 0.78 mm. The distance between the fourth lens 117 and the fifth lens 119 may be greater than the minimum distance between the third lens 115 and the fourth lens 117 , for example, the third lens 115 . ) and the fourth lens 117 may be 1.2 times or more. The distance between the fourth lens 117 and the fifth lens 119 may be 50% or less less than the central thickness of the fifth lens 119, and 30 of the central thickness of the fifth lens 119. % to 50%.

The distance D1 between the object-side surfaces of the fourth and fifth lenses 117 and 119 and the first lens 111 or between the third lens 115 may be variable, and the second lens group 120 ), the distance BFL1 between the upper surface and the image sensor 190 may vary, and the BFL1 may be 8.5 mm or less, for example, in the range of 7 mm to 8.5 mm. In this case, the focal length of the first lens 111 may be 11 mm or less, for example, in the range of 8 mm to 9 mm, and the focal length of the fifth lens 119 may be in the range of 16 mm or less, for example, 12 mm to 16 mm.

Table 3 shows the lens characteristics of the lens optical system according to the second embodiment.

second embodiment noodle # Radius Surface type Thickness/
Interval Index Abbe# Aperture first lens S1 6.029 ASP 1.80 1.52 56.0 5.499581469 S2 -49.672 ASP 2.63 4.843362781 second lens S3 -9.542 ASP 0.30 1.61 26.6 4.000010545 S4 4.784 ASP 0.10 3.947161225 third lens S5 3.463 ASP 1.43 1.53 56.0 3.995512215 S6 -4.084 ASP 0.10-0.23
(variable) 3.992976967 4th lens S7 -5.931 ASP 0.46 1.52 56.0 3.228620367 S8 3.653 ASP 0.74 2.858746249 5th lens S9 17.779 ASP 1.80 1.66 20.4 3.033 S10 -19.596 ASP 0.10 3.881 filter S11 Infinity SPH 0.110 1.52 64.20 S12 Infinity SPH 0.452 image sensor Image Infinity SPH 0.000

In Table 3, the ASP indicates an aspherical surface, and in the items of each surface (S1-S10), the thickness indicates the thickness (unit, mm) of each lens on the optical axis, and the interval indicates the spacing between the two lenses aligned on the optical axis. (unit, mm) is indicated. The thickness of S11 may be the thickness of the filter, and the thickness of the Image may be the thickness of the image sensor.

The interval D1 between the third lens 115 and the fourth lens 117 may be varied, and as shown in FIGS. 2 and 3 , for example, from the first interval D1 to the second interval D2 ), or may decrease from the second interval D2 to the first interval D1. For example, when the first interval D1 is in the range of 0.43 mm±0.05 mm (initial interval), the second lens group 120 is moved in the object side direction, and the second interval D2 is the maximum In the case of 2 mm±0.5 mm, the distance between the second lens group 120 and the first lens group 110 may be maximum. That is, since the distance between the second lens group 120 and the first lens group 110 increases or decreases, the focus can be achieved. The second lens group 120 may be moved along the optical axis in a range of 2 mm or less, for example, 0.05 mm to 1.8 mm.

Table 4 is a table showing the aspheric coefficients of the respective lens surfaces S1-S10 in the optical system of the second embodiment.

surface K A B C D S1 -1.738921501 0.0014865 0.000117625 7.48E-06 8.98E-07 S2 90 0.001956588 0.000267494 2.50E-05 -4.14E-06 S3 17.98840945 0.008117008 -0.000866518 3.84E-05 -3.34E-05 S4 -1.019061012 -0.002059087 0.001461267 -0.000447224 -1.09E-04 S5 -7.680290945 0.008253995 -0.002063617 0.000289911 1.22E-05 S6 -5.763166467 -0.009162122 0.000866283 -0.000356067 9.65E-05 S7 -55.53130748 0.019890668 -0.005784545 0.000727154 2.59E-04 S8 -8.101737996 0.0597683 -0.022849203 0.008635191 -0.002144272 S9 -35.88696898 -0.017009997 0.00258435 -0.002871913 0.001569213 S10 90 -0.00732628 -0.000852976 0.000591673 1.45E-05 surface E F G H J S1 2.20E-08 -8.81E-09 4.58E-10 1.30E-10 -7.09E-14 S2 9.41E-07 -8.48E-08 2.87E-08 -6.28E-09 6.10E-10 S3 -8.37E-06 3.51E-06 3.16E-06 -1.17E-06 1.15E-07 S4 4.88E-06 4.56E-06 1.27E-06 -5.58E-08 -5.13E-08 S5 -2.62E-05 -4.58E-06 1.95E-06 5.14E-07 -1.15E-07 S6 2.35E-05 -1.11E-05 -2.32E-06 1.37E-06 -1.41E-07 S7 -5.23E-05 -2.20E-05 7.31E-06 -4.80E-07 -2.11E-09 S8 0.000277534 1.34E-06 -1.55E-06 -1.93E-07 6.56E-08 S9 -0.000524322 2.61E-05 3.69E-05 -1.19E-05 1.22E-06 S10 -0.000239542 0.000132316 -3.02E-05 2.69E-06 -1.52E-08

In Table 4, K is a conic constant, A, B, C, D, ?? may mean an aspheric constant. As the second lens group 120 moves along the optical axis toward the object side or the image side, the fourth lens 117 has a distance from the third lens 115. can be varied, and the problem of increasing the length or space of the optical system can be suppressed. Also, as the size of the image sensor 190 increases, it is possible to solve the problem that the length of the lens optical system increases according to the position of the object.

The optical system according to the embodiment of the present invention may satisfy at least one of the following equations. Accordingly, when the optical system satisfies at least one of the following equations, the optical system may have improved optical properties. Also, when the optical system satisfies at least one of the above equations, the amount of light may be maintained through focus adjustment.

[Equation 1]

10 < EFL < 35

In Equation 1, EFL means an effective focal length (mm) at the initial position of the optical system. In detail, the EFL of the optical system may be 13 < EFL < 25. In more detail, the EFL of the optical system may be 13 < EFL < 23.

[Equation 2]

1 < L1S1/L1S2 < 1.5

In Equation 2, L1S1 denotes a clear aperture (mm) of the first object-side surface S1 of the first lens 111 , and L1S2 denotes the image-side second surface of the first lens 111 . (S2) means the size of the effective diameter (clear aperture) (mm). In detail, L1S1/L1S2 may satisfy 1 < L1S1/L1S2 < 1.3. In detail, L1S1/L1S2 may satisfy 1 < L1S1/L1S2 < 1.2.

[Equation 3]

0.05 < R_L1/R_L3 < 0.7

In Equation 3, R_L1 means the radius of curvature (mm) of the object-side surface (first surface S1) of the first lens 111, and R_L3 is the object-side surface (th It means the radius of curvature (mm) of the three surfaces (S3)). In detail, it may be 0.1<R_L1/R_L3<0.5.

[Equation 4]

4 < TH_L1/TH_L2 < 8

In Equation 4, TH_L1 denotes a central thickness (mm) of the first lens 111 , and TH_L2 denotes a central thickness (mm) of the second lens 112 . In detail, a condition of 4.5 < TH_L1/TH_L2 < 7.5 may be satisfied. In more detail, a condition of 5 < TH_L1/TH_L2 < 7 may be satisfied.

[Equation 5]

0.32 < CH _n(n<4) /CA _n(n<4) < 0.98

In Equation 5, CH _n(n<4) means the minimum size (clear height) (mm) of the effective diameter of the nth lens. In detail, CH _{n (n<4)} means the minimum size (mm) of the effective diameter of one lens selected from among the first to fifth lenses 111 , 113 , 115 , 117 and 119 . In addition, CA _n(n<4) means the maximum size (clear aperture) (mm) of the effective diameter of the nth lens. In detail, CH _{n (n<4)} means the maximum size (mm) of the effective diameter of one lens selected from among the first to fifth lenses 111 , 113 , 115 , 117 and 119 .

Here, in detail, 0.4 < CH _n(n<4) /CA _n(n<4) < 0.75 or 0.5 < CH _n(n<4) /CA _n(n<4) < 0.6 may be satisfied.

[Equation 6]

1 < |f1| - |f2| < 11

In Equation 6, f1 denotes a focal length (mm) of the first lens 111 , and f2 denotes a focal length (mm) of the second lens 112 .

[Equation 7]

1.5 < BFL/ImgH < 5

In Equation 7, back focus length (BFL) is the image sensor from the image side of the lens 119 closest to the image sensor 190 among the plurality of lenses when the second lens group 120 is in the initial state. (190) means the distance in the optical axis direction (mm). In addition, ImgH means a value of 1/2 of the diagonal length (mm) of the effective area of the image sensor 190 . That is, the ImgH denotes a vertical distance (mm) from the optical axis of the upper surface of the image sensor 190 to one field area. Specifically, 2 < BFL/ImgH < 3.5 may be satisfied.

[Equation 8]

0.30 < BFL/EFL < 0.75

In Equation 8, when the second lens group 120 is in an initial state, the back focus length (BFL) is the image sensor from the image side of the lens 119 closest to the image sensor 190 among the plurality of lenses. (190) means the distance in the optical axis direction (mm). In addition, EFL means an effective focal length (mm) of the optical system. Specifically, 0.4 < BFL/EFL < 0.65 may be satisfied.

[Equation 9]

1.8 < TTL/BFL < 2.7

In Equation 9, TTL (Total Track Length) is from the object-side surface (first surface S1) of the lens (first lens 111) closest to the object-side among the plurality of lenses to the image sensor 190 of the optical axis direction (mm). In addition, a back focus length (BFL) refers to a distance (mm) in the optical axis direction from the image side of the lens 119 closest to the image sensor 190 among the plurality of lenses to the image sensor 190 . Specifically, 2 < TTL/BFL < 2.5 may be satisfied.

[Equation 10]

|f3| ≤ |f4| < |f2| < |f1| < |f5|

In Equation 10, f1 denotes a focal length of the first lens 111 and f2 denotes a focal length of the second lens 112 . In addition, f3 denotes a focal length of the third lens 113 , f4 denotes a focal length of the fourth lens 114 , and f5 denotes a focal length of the fifth lens 115 . It means focal length.

[Equation 11]

0.3 < TH_L1/d12 < 1

In Equation 11, TH_L1 means a center thickness (mm) of the first lens 111 , and d12 is an optical axis (Lz) direction distance between the first lens 111 and the second lens 112 (mm) means

[Equation 12]

0. 3 < f1/EFL < 1

In Equation 12, f1 denotes a focal length (mm) of the first lens 111, and EFL denotes an effective focal length (mm) of the optical system.

The optical system according to the first and second embodiments may satisfy at least one or two or more of Equations 1 to 12. In particular, the optical system may provide a large effective diameter of the first lens 111 to have improved optical properties. In addition, when the optical system satisfies at least one or two or more of Equations 1 to 12, it may be applicable to a portable terminal or a vehicle camera.

5 is an example of a cross-sectional side view of a camera module having an optical system according to an embodiment of the present invention.

Referring to FIG. 5 , the camera module supports the substrate 195 on which the image sensor 190 is disposed, the first lens holder 150 supporting the first lens group 110 , and the second lens group 120 . It may include a second lens holder 153, and driving units (155, 156).

The substrate 195 may be a flexible or non-flexible substrate, and may be implemented as an FPCB. An image sensor 190 is mounted on the substrate 195 , and a lower end of the first lens holder 150 may be coupled to the periphery thereof.

The first lens group 110 is supported on the upper part 152 of the first lens holder 150 , for example, the outer circumference of the first lens 111 is supported. The first lens holder 150 has a through hole 151 passing therein, and the first lens 111 is positioned on the through hole 151 .

A second lens holder 153 supporting the second lens group 153 is disposed inside the through hole 151 or inside the first lens holder 150 . The second lens holder 153 is disposed between the first lens group 110 and the image sensor 190, and moves in the optical axis direction (M1) when performing an Auto Focusing (hereinafter, AF) function. can be The second lens holder 153 may be supported by an elastic spring, and may be supported when moving in the optical axis direction.

The driving units 155 and 156 may be disposed on the outside or/and the lower periphery of the second lens holder 153 , and may be disposed in an area that does not obstruct the path of light. The driving units 155 and 156 may include at least one of a piezo member, an actuator, and a stamping motor. The driving units 155 and 156 may move the second lens holder 153 in the optical axis direction. For example, the piezo member may control the amount of movement of the second lens holder 153 that linearly moves according to a physical displacement caused by an applied electric field.

The driving units 155 and 156 may include an actuator including a mover 155 disposed outside the second lens holder 153 and a stator 156 disposed inside the first lens holder 150 . have. When the mover 155 is a magnet, the stator 156 may be a coil. As another example, when the mover 155 is a coil, the stator 156 may be a magnet.

When external power is applied to the driving units 155 and 156 , a magnetic field is formed between the driving unit 155 and the movable element 155 according to the polarity of the power applied to the stator 156 . At this time, the mover 155 moves toward the first lens group 110 or toward the image sensor 190 along the optical axis together with the second lens holder 153, and the second lens group ( By the movement of the 120 , the light incident through the first lens group 110 may be focused on the image sensor 190 .

Here, the camera module may include stoppers 161 and 162 for limiting movement of the second lens group 120 . The stopper 161 may include a first stopper 161 at a lower portion and a second stopper 162 at an upper portion. The material of the first and second stumps 161 and 162 may be a metal or a non-metal material. The material of the first and second stoppers 161 and 162 may be an elastic metal or an inelastic material.

The first stopper 161 may be disposed around the image sensor 190 and protrude higher than an upper end of the filter 192 . The first stopper 161 may vertically overlap the second lens holder 153 . The first stopper 161 is disposed between the second lens holder 153 and the substrate 195 , and when the second lens holder 153 is moved toward the image sensor 190 , the movement is restricted. .

The second stopper 162 protrudes from below the upper part 152 of the first lens holder 150 toward the substrate 195 , and protrudes below or equal to the image side surface of the first lens group 110 . can be The second stopper 162 may vertically overlap the second lens holder 153 . The second stopper 162 is disposed between the second lens holder 153 and the upper portion 152 of the first lens holder 150 , and the second lens holder 153 holds the first lens group 110 . As you move towards it, you limit your movement.

Here, according to the total refractive power of the second lens group 120, when an object to be focused moves from a short distance to a long distance or moves from a long distance to a short distance, the second lens group 120 moves toward the object side or the image side. can move Accordingly, the height of the camera module may be performed while maintaining the height of the object infinity. The second lens group 120 may be moved along the optical axis in a range of 2 mm or less, for example, 0.05 mm to 1.8 mm.

According to an embodiment of the present invention, the first lens group 110 having at least two lenses close to the object side is not moved, and the second lens group 120 and 220 disposed between the first lens group 110 and 210 and the image sensor 190 . By moving the second lens holder 153 having , in the optical axis direction, it is possible to focus by moving only the inner lens without moving the entire lens. Accordingly, even if the diagonal length of the image sensor 190 is increased, the focus may be adjusted using the second lens group 120 without increasing the overall module size.

6 is a perspective view illustrating an example of a moving device to which an optical system according to an embodiment(s) of the present invention is applied.

As shown in FIG. 6 , the mobile terminal 1500 may include a camera module 1520 , a flash module 1530 , and an auto-focus device 1510 provided on one side or the rear side. Here, the autofocus device 1510 may include a surface light emitting laser device and a light receiving unit as a light emitting layer.

The flash module 1530 may include an emitter emitting light therein. The flash module 1530 may be operated by a camera operation of a mobile terminal or a user's control. The camera module 1520 may include an image capturing function and an auto focus function. For example, the camera module 1520 may include an auto-focus function using an image.

The auto-focus device 1510 may include an auto-focus function using a laser. The auto focus device 1510 may be mainly used in a condition in which the auto focus function using the image of the camera module 1520 is deteriorated, for example, in proximity of 10 m or less or in a dark environment.

Features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

In addition, although the embodiment has been described above, it is only an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are exemplified above in a range that does not depart from the essential characteristics of the present embodiment. It can be seen that various modifications and applications that have not been made are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

110: first lens group 111: first lens
113: second lens 115: third lens
117: fourth lens 119: fifth lens
120: second lens group 190: image sensor

Claims (14)

a first lens group having a plurality of lenses;
image sensor;
a second lens group having a plurality of lenses between the first lens group and the image sensor and having a variable distance from the first lens group; and
An optical filter is included between the image sensor and the second lens group,
The first lens group may include: a first lens having positive refractive power and having a convex object-side first surface and a concave image-side second surface; a second lens having negative refractive power and having a third object-side surface concave and an image-side fourth surface concave; and a third lens having positive refractive power, the fifth surface of the object being convex and the sixth surface of the image being convex,
The refractive power of the first lens group has a positive refractive power,
The refractive power of the second lens group has a negative refractive power. The method of claim 1,
The second lens group may include: a fourth lens having negative refractive power and having a seventh object-side surface concave and an image-side eighth surface concave; and a fifth lens having positive refractive power, wherein the object-side ninth surface is convex and the image-side tenth surface is convex. 3. The method of claim 2,
An effective diameter of the first surface and the second surface of the first lens is the largest among the second to fifth lenses. 4. The method of claim 2 or 3,
The optical system satisfies 10 < EFL < 35,
The EFL represents the effective focal length (mm) (Effective Focal Length) of the optical system. 4. The method of claim 2 or 3,
The optical system satisfies 1.5 < BFL / ImgH < 5,
The back focus length (BFL) is a distance in the optical axis direction between the image sensor and the image-side tenth surface of the fifth lens when the second lens group is in an initial state, and ImgH is a diagonal direction of the effective area of the image sensor 1/2 the length of the optical system. 4. The method of claim 2 or 3,
The optical system satisfies 0.30 < BFL / EFL < 0.75,
The back focus length (BFL) is a distance in the optical axis direction between the image sensor and the image sensor tenth surface of the fifth lens when the second lens group is in an initial state, and the EFL is an effective focal length of the optical system. Length), the optical system. 4. The method of claim 2 or 3,
The optical system satisfies 1.8 < TTL/BFL < 2.7,
The TTL (Total Track Length) is a distance in the optical axis direction between the first surface of the first lens and the image sensor 190, and the BFL (Back Focus Length) is the upper tenth surface of the fifth lens and the image. Optical system, which is the distance in the optical axis direction between the sensors (190). Board;
an image sensor disposed on the substrate;
a first lens group including a plurality of lenses on the image sensor;
a second lens group including a plurality of lenses between the first lens group and the image sensor;
a first lens holder supporting the first lens group;
an optical filter between the image sensor and the second lens group;
a second lens holder supporting the second lens group in the first lens holder; and
and a driving unit for moving the second lens holder in an optical axis direction,
The first lens group may include: a first lens having positive refractive power and having a convex object-side first surface and a concave image-side second surface; a second lens having negative refractive power and having a third object-side surface concave and an image-side fourth surface concave; and a third lens having positive refractive power, the fifth surface of the object side being convex and the sixth surface of the image side being convex,
The refractive power of the first lens group has a positive refractive power,
The refractive power of the second lens group has a negative refractive power, the camera module. 9. The method of claim 8,
The second lens group may include: a fourth lens having negative refractive power and having a seventh object-side surface concave and an image-side eighth surface concave; and a fifth lens having positive refractive power, the object-side ninth surface is convex, and the image-side tenth surface is convex,
The effective diameter of the first surface and the second surface of the first lens is the largest among the second to fifth lenses, the camera module. 10. The method according to claim 8 or 9,
Each of the stoppers for limiting the movement of the second lens holder is included in the upper and lower portions of the first lens holder,
Each of the stoppers vertically overlaps the second lens holder, the camera module. 10. The method according to claim 8 or 9,
The driving unit includes a mover disposed outside the second lens holder and an actuator having a fixing part facing the mover inside the first lens holder. 10. The method according to claim 8 or 9,
The first lens group includes three or less lenses,
The second lens group includes 2 to 4 lenses, the camera module. 10. The method according to claim 8 or 9,
TTL in the camera module ranges from 10mm to 25mm,
The effective focal length is in the range of 10 mm to 35 mm,
The amount of movement of the second lens group is 2 mm or less, the camera module. 10. The method according to claim 8 or 9,
The Abbe numbers of the second and fifth lenses are lower than the Abbe numbers of the first, third, and fourth lenses,
The Abbe's number of the first, third, and fourth lenses is 50 or more, the camera module.

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