KR20240054100A - Optical system and camera module - Google Patents

Abstract

An optical system according to an embodiment of the present invention includes first to seventh lenses disposed along an optical axis, the first lens has negative refractive power, and the second to seventh lenses include: The composite refractive power has a positive refractive power, the effective diameter of the third lens is the smallest among the first to third lenses, and the thickness of the second lens at the optical axis is equal to that of the first lens and the second lens. greater than the distance between lenses.

Description

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

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

ADAS (Advanced Driving Assistance System) is an advanced driver assistance system to assist the driver in driving. It senses the situation ahead, judges the situation based on the sensed results, and controls the vehicle's behavior based on the situation judgment. It consists of For example, ADAS sensor devices detect vehicles in front and recognize lanes. Afterwards, when the target lane, target speed, and target ahead are determined, the vehicle's ESC (Electrical Stability Control), EMS (Engine Management System), and MDPS (Motor Driven Power Steering) are controlled. Typically, ADAS can be implemented as an automatic parking system, a low-speed city driving assistance system, and a blind spot warning system.

Sensor devices for detecting the situation ahead in ADAS include GPS sensors, laser scanners, front radar, and Lidar, and the most representative ones are cameras for photographing the front, rear, and sides of the vehicle.

These cameras can be placed outside or inside a vehicle to detect the surrounding conditions of the vehicle. Additionally, the camera may be placed inside the vehicle to detect the situation of the driver and passengers. For example, the camera can photograph the driver from a location adjacent to the driver and detect the driver's health status, drowsiness, drinking, etc. In addition, the camera can photograph the passenger at a location adjacent to the passenger, detect whether the passenger is sleeping, state of health, etc., and provide information about the passenger to the driver.

In particular, the most important element in obtaining an image from a camera is the imaging lens that forms the image. Recently, interest in high performance, such as high image quality and high resolution, is increasing, and research is being conducted on optical systems that include multiple lenses to realize this. However, there is a problem that the characteristics of the optical system change when the camera is exposed to harsh environments, such as high temperature, low temperature, moisture, high humidity, etc., outside or inside the vehicle. In this case, the camera has a problem in that it is difficult to uniformly derive excellent optical and aberration characteristics.

Therefore, a new optical system and camera that can solve the above-mentioned problems are required.

The embodiment seeks to provide an optical system and camera module with improved optical characteristics.

The embodiment seeks to provide an optical system and a camera module with excellent optical performance in low to high temperature environments.

Embodiments seek to provide an optical system and a camera module that can prevent or minimize changes in optical properties in various temperature ranges.

In order to solve the above technical problem, the optical system according to an embodiment of the present invention includes first to seventh lenses disposed along the optical axis, the first lens has a negative refractive power, and the second lens The composite refractive power of the lens to the seventh lens has a positive refractive power, the effective diameter of the third lens is the smallest among the first to third lenses, and the thickness of the second lens at the optical axis is the It is greater than the distance between the first lens and the second lens.

The fourth to seventh lenses may be made of plastic, and at least one of the first to third lenses may be made of glass.

Among the first to seventh lenses, the first lens may have the largest effective diameter.

The first lens may have a meniscus shape convex toward the object, and the second lens may have a meniscus shape convex toward the sensor.

Among the first to seventh lenses, the lens with the smallest absolute value of focal length may be one of the fifth to seventh lenses.

The absolute values of the focal lengths of the third to fifth lenses may satisfy the following conditional expression. <Conditional expression> |F4|≥ |F3| ≥ |F5| (In the above conditional expression, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens.)

The second lens may have negative refractive power, and the thickness of the second lens may be the largest among the first to seventh lenses on the optical axis.

The third lens may have a biconvex shape.

The conditional expression below can be satisfied. <Conditional expression> 2 < |L4R2| - |L5R1| < 5 (In the above conditional expression, L4R2 is the radius of curvature of the sensor side of the fourth lens, and L5R1 is the radius of curvature of the object side of the fifth lens.)

The condition below can be satisfied. <Conditional expression> 1 < |L5R2| - |L6R1| < 3 (In the above conditional expression, L5R2 is the radius of curvature of the sensor side of the fifth lens, and L6R1 is the radius of curvature of the object side of the fifth lens.)

In order to solve the above technical problem, an optical system according to another embodiment of the present invention includes first to seventh lenses disposed along an optical axis, the first lens has positive refractive power, and the second lens has a positive refractive power. The second lens has negative refractive power, the effective diameter of the third lens is the smallest among the first to third lenses, and the thickness of the first lens at the optical axis is greater than the thickness of the second lens. , the thickness of the second lens at the optical axis is greater than the thickness of the sixth lens.

The fourth to seventh lenses may be made of plastic, and at least one of the first to third lenses may be made of glass.

Among the first to seventh lenses, the first lens may have the largest effective diameter.

The first lens and the second lens may have a meniscus shape convex toward the sensor.

Among the first to seventh lenses, the lens with the smallest absolute value of focal length may be one of the fifth to seventh lenses.

The absolute values of the focal lengths of the third to fifth lenses may satisfy the following conditional expression. <Conditional expression> |F4|≥ |F3| ≥ |F5| (In the above conditional expression, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens.)

The second lens may have negative refractive power, and the thickness of the first lens may be the largest among the first to seventh lenses on the optical axis.

The third lens may have a biconvex shape.

The conditional expression below can be satisfied. <Conditional expression> 2 < |L4R2| - |L5R1| < 5 (In the above conditional expression, L4R2 is the radius of curvature of the sensor side of the fourth lens, and L5R1 is the radius of curvature of the object side of the fifth lens.)

The conditional expression below can be satisfied. <Conditional expression> 1 < |L5R2| - |L6R1| < 3 (In the above conditional expression, L5R2 is the radius of curvature of the sensor side of the fifth lens, and L6R1 is the radius of curvature of the object side of the fifth lens.)

The optical system and camera module according to the embodiment may have improved optical characteristics. In detail, in the optical system according to the embodiment, a plurality of lenses may have a set thickness, refractive power, and distance from adjacent lenses. Accordingly, the optical system and camera module according to the embodiment can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in a set angle of view range, and can have good optical performance in the periphery of the angle of view.

Additionally, the optical system and camera module according to the embodiment may have good optical performance in a low to high temperature range (-40°C to 105°C). In detail, a plurality of lenses included in the optical system may have set materials, refractive powers, and refractive indices. Accordingly, when the refractive index of each lens changes due to temperature change and the focal length of each lens changes due to this, mutual compensation can be made by the plastic lens and the glass lens. That is, the optical system can effectively distribute refractive power in a temperature range from low to high temperatures, and prevent or minimize changes in optical properties in the temperature range from low to high temperatures. Therefore, the optical system and camera module according to the embodiment can maintain improved optical properties in various temperature ranges.

Additionally, the optical system and camera module according to the embodiment can satisfy the angle of view set through a mixture of a plastic lens and a glass lens and implement excellent optical characteristics. Because of this, the optical system can provide a slimmer vehicle camera module. Accordingly, the optical system and camera module can be provided for various applications and devices, and can have excellent optical properties even in harsh temperature environments, for example, when exposed to the exterior of a vehicle or inside a vehicle at high temperatures in the summer.

1 is a side cross-sectional view of an optical system and a camera module having the same according to a first embodiment.
FIG. 2 is a side cross-sectional view for explaining the relationship between the nth and n-1th lenses of FIG. 1.
Figure 3 is a table showing the lens characteristics of the optical system of Figure 1.
Figure 4 is a table showing the aspheric coefficients of lenses in the optical system of Figure 1.
Figure 5 is a table showing the thickness of each lens and the spacing between adjacent lenses in the optical system of Figure 1.
FIG. 6 is a table showing Sag values of lens surfaces of the third to sixth lenses in the optical system of FIG. 1.
FIG. 7 is a table showing CRA (Chief Ray Angle) data at room temperature, low temperature, and high temperature according to the position of the image sensor in the optical system of FIG. 1.
FIG. 8 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 1 at room temperature.
FIG. 9 is a graph showing data on the diffraction MTF of the optical system of FIG. 1 at low temperature.
FIG. 10 is a graph showing data on the diffraction MTF of the optical system of FIG. 1 at high temperature.
FIG. 11 is a graph showing data on aberration characteristics of the optical system of FIG. 1 at room temperature.
FIG. 12 is a graph showing data on aberration characteristics of the optical system of FIG. 1 at low temperature.
FIG. 13 is a graph showing data on aberration characteristics of the optical system of FIG. 1 at high temperature.
Figure 14 is a graph showing relative illuminance according to the height of the image sensor according to the first embodiment.
Figure 15 is a side cross-sectional view of an optical system and a camera module having the same according to the second embodiment.
FIG. 16 is a side cross-sectional view for explaining the relationship between the nth and n-1th lenses of FIG. 15.
Figure 17 is a table showing the lens characteristics of the optical system of Figure 15.
FIG. 18 is a table showing the aspheric coefficients of lenses in the optical system of FIG. 15.
FIG. 19 is a table showing the thickness of each lens and the gap between adjacent lenses in the optical system of FIG. 15.
FIG. 20 is a table showing Sag values of lens surfaces of the third to sixth lenses in the optical system of FIG. 15.
FIG. 21 is a table showing CRA (Chief Ray Angle) data at room temperature, low temperature, and high temperature according to the position of the image sensor in the optical system of FIG. 15.
FIG. 22 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 15 at room temperature.
FIG. 23 is a graph showing data on the diffraction MTF of the optical system of FIG. 15 at low temperature.
FIG. 24 is a graph showing data on diffraction MTF at high temperature of the optical system of FIG. 15.
Figure 25 is a graph showing data on aberration characteristics of the optical system of Figure 15 at room temperature.
Figure 26 is a graph showing data on the aberration characteristics of the optical system of Figure 15 at low temperature.
Figure 27 is a graph showing data on the aberration characteristics of the optical system of Figure 15 at high temperature.
Figure 28 is a graph showing relative illuminance according to the height of the image sensor according to the second embodiment.
Figure 29 is an example of a vehicle having an optical system according to an embodiment of the invention.

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 or replacing.

In addition, terms (including technical and scientific terms) used in this embodiment have meanings that can be generally understood by those skilled in the art to which this embodiment belongs, unless specifically defined and described. 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.

Additionally, the terms used in this embodiment 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, in describing the components of this embodiment, 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, sequence, or order of the component.

And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, that component is directly 'connected', 'coupled', or 'connected' to that other component. In addition to cases, it may also include cases where the component is 'connected', 'coupled', or 'connected' by another component between that component and that other component.

Additionally, when described as being formed or disposed “on top” or “bottom” of each component, “top” or “bottom” means that the two components are directly adjacent to each other. This includes not only cases of contact, but also cases where one or more other components are formed or disposed between two components. In addition, when expressed as “top” or “bottom,” the meaning of not only the upward direction but also the downward direction can be included based on one component.

In the description of the invention, “object side” may refer to the surface of the lens facing the object side based on the optical axis (OA), and “sensor side” may refer to the surface of the lens facing the imaging surface (image sensor) based on the optical axis. It can mean side. “Object side” may be “water side”, and “sensor side” may be “upper side”. That one side of the lens is convex may mean a convex shape in the optical axis or paraxial region, and that one side of the lens is concave may mean a concave shape in the optical axis or paraxial region. The radius of curvature, center thickness, and optical axis spacing between lenses listed in the table for lens data may refer to values (unit, mm) at the optical axis. 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. The size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method. The paraxial area refers to a very narrow area near the optical axis, and is an area where the distance at which light rays fall from the optical axis (OA) is almost zero. Hereinafter, the meaning of optical axis may include the center of each lens or a very narrow area near the optical axis.

1 and 15, the optical systems 1000 and 2000 according to the first and second embodiments of the present invention may include five or more lenses. The optical systems 1000 and 2000 and camera modules having them may be mounted inside or outside the vehicle to monitor the driver or sense external objects or lanes. The material of the lenses can be glass or plastic, and the coefficient of linear expansion of glass is smaller than that of plastic. Accordingly, a glass lens is used to prevent changes in the focal imaging position due to temperature changes. However, glass lenses are more expensive than plastic lenses, and there is a problem in that it is difficult to meet the demand for lower costs. Accordingly, the lenses in the optical systems 1000 and 2000 are required to be a mixture of glass lenses and plastic lenses. By employing these plastic lenses, the optical system (1000, 2000) can reduce the thickness of the plastic lenses, providing lighter weight and lower costs, and the plastic lenses provide good correction for various aberrations such as spherical aberration and chromatic aberration. It may be possible. Additionally, since plastic lenses can provide aspherical lenses, distortion in the peripheral area can be minimized.

The optical systems 1000 and 2000 may include n lenses, where the nth lens may be the last lens adjacent to the image sensor 300, and the n-1th lens may be the lens closest to the last lens. n is an integer of 5 or more, for example, may be 5 to 8. The n lenses may have a ratio of glass lenses to plastic lenses in the range of 2:3 to 2:6 or 3:4 to 3:5.

The optical systems 1000 and 2000 may include a plurality of lens groups LG1 and LG2. In detail, each of the plurality of lens groups LG1 and LG2 includes at least one lens. For example, the optical systems 1000 and 2000 may include a first lens group LG1 and a second lens group LG2 sequentially arranged along the optical axis OA from the object side toward the image sensor 300. there is.

The number of lenses for each of the first lens group (LG1) and the second lens group (LG2) may be different. The number of lenses of the second lens group (LG2) may be greater than the number of lenses of the first lens group (LG1), for example, 4 times or 5 times the number of lenses of the first lens group (LG1). The first lens group LG1 may include at least one lens. The first lens group LG1 may have three or fewer lenses. The first lens group LG1 may preferably include one lens. The second lens group (LG2) may include two or more lenses. The second lens group (LG2) may have 4 to 7 elements. The second lens group (LG2) may preferably have 6 lenses.

The first lens group LG1 may include at least one lens made of glass. The first lens group LG1 may provide the lens closest to the object side as a glass lens. This glass material has a small amount of expansion and contraction due to changes in external temperature, and its surface is less likely to be scratched, preventing surface damage.

The lens material of the second lens group LG2 may be a mixture of at least one lens made of glass and at least one lens made of plastic. In the second lens group LG2, at least one plastic lens may be placed closer to the sensor than a glass lens. The second lens group LG2 may include two or more lenses made of glass, for example, 2 to 4 lenses made of glass. The second lens group LG2 may include, for example, 2 to 6 lenses. As another example, the second lens group LG2 may have one or more lenses made of plastic. The second lens group LG2 may include two or more plastic lenses, for example, two to four plastic lenses.

At least one lens closest to the object within the optical systems 1000 and 2000 may be made of glass. Three or more lenses closest to the object, for example, three to five lenses, may be made of glass. Since glass lenses have a smaller rate of change in contraction and expansion due to temperature changes than plastic lenses, glass lenses can be placed in an area adjacent to the outside of the lens barrel.

At least one lens closest to the image sensor 300 within the optical systems 1000 and 2000 may be made of plastic. For example, at least two lenses closest to the image sensor 300 may be made of plastic, and preferably, at least two lenses adjacent to the image sensor 300 may be made of plastic. That is, since the n-th and n-1-th lenses in the optical systems 1000 and 2000 are disposed as plastic lenses, various aberrations of light on the incident side of the image sensor 300 can be corrected.

Within the optical systems 1000 and 2000, lenses made of plastic may be continuously arranged, and lenses made of glass may be arranged continuously. Within the optical systems 1000 and 2000, lenses made of plastic may be disposed between lenses made of glass. Within the optical systems 1000 and 2000, lenses made of glass may be disposed between lenses made of plastic.

Each lens 101-107 and 201-207 may have an object side and a sensor side. In an optical system, the number of lenses with an aspherical sensor side and an aspherical object side may be greater than the number of plastic lenses. In an optical system, the number of lenses with a spherical sensor side and a spherical object side may be smaller than a lens with aspherical surfaces on both sides. Since the optical systems 1000 and 2000 are equipped with more aspherical lenses than spherical lenses, various aberrations can be corrected.

Among the lenses of the optical systems 1000 and 2000, the lens with the maximum refractive index may be located in the first lens group LG1 or adjacent to the object. The maximum refractive index may be 1.8 or more. The color dispersion of incident light can be increased by a lens with the highest refractive index, and the center thickness can be thinner than the edge thickness. Additionally, since the lens with the maximum refractive index is disposed on the object side, it is easy to change the radius of curvature of the second and subsequent lenses and the center thickness can be increased.

Within the optical systems 1000 and 2000, a lens having the maximum effective diameter may be placed at the center of the object side and the sensor side. As you move from the object side to the sensor side, the effective diameter of the lens can increase and then decrease. As you move from the object side to the sensor side, the effective diameter of the lens can become smaller, then larger, and then smaller again. Through this, since the light incident on the optical systems (1000, 2000) moves away from the optical axis and then converges towards the optical axis, the optical systems (1000, 2000) can form a stable optical path.

The effective diameter may be the diameter of the effective area where effective light is incident on each lens. The effective diameter is the length in the direction (X, Y) perpendicular to the optical axis, and is the average of the effective diameter of each lens on the object side and the effective diameter on the sensor side. “Diameter of the lens surface” may mean “effective diameter of the lens.” The “diameter of the lens” may be the diameter of the entire lens including the flange portion of the lens in addition to the effective area of the lens. Although the flange of the lens is not shown in FIGS. 1, 2, 15, and 16, the flange may be a part that protrudes from the side of the lens in a direction perpendicular to the optical axis in order to couple the lens to the barrel. The flange may not allow effective light to enter. In order for the lens to be coupled to the barrel, spacers may be additionally disposed between the flanges of different lenses.

Each of the lenses 101-107 and 201-207 may include an effective area and an unactive area. The effective area may be an area through which light incident on each of the lenses passes. In other words, the effective area can be defined as an effective area or effective diameter in which the incident light is refracted to realize optical characteristics. The unactive area may be placed around the active area. The non-effective area may be an area where effective light is not incident from the plurality of lenses. In other words, the non-effective area may be an area unrelated to optical characteristics. Additionally, the end of the non-effective area may be an area fixed to a lens barrel or the like that accommodates the lens.

The total top length (TTL) within the optical systems 1000 and 2000 may be greater than 2 times, for example, greater than 4 times and less than or equal to 12 times Imgh. Total track length (TTL) is the distance on the optical axis (OA) from the center of the object side of the first lens to the image surface of the image sensor 300. Imgh is the distance from the optical axis (OA) to the diagonal end of the image sensor 300 or 1/2 of the maximum diagonal length. Within the optical system (1000, 2000), the effective focal length (EFL) is more than 10 mm and the angle of view (FOV) is less than 45 degrees, so it can be provided as a standard optical system in a vehicle camera module. For example, the optical system and camera module according to the embodiment may be applied to a camera for an Advanced Driving Assistance System (ADAS) installed inside or outside a vehicle.

The optical systems 1000 and 2000 may have TTL/Imgh conditions of 5 or more and 7.5 or more, for example, 7 or more and 9 or less. The optical systems 1000 and 2000 set the TTL/Imgh value to 7 or more and 9 times or less, thereby providing a vehicle lens optical system. The total number of lenses in the first and second lens groups (LG1, LG2) is 8 or less. Accordingly, the optical systems 1000 and 2000 can provide images without exaggeration or distortion.

The effective diameter of at least one plastic lens within the optical systems 1000 and 2000 may be smaller than the length of the image sensor 300. The effective diameter is the diameter or length of the effective area where light is incident. The length of the image sensor 300 is the maximum length of the diagonal in the direction perpendicular to the optical axis OA. In the optical system (1000, 2000), the number of lenses with an effective diameter larger than the length of the image sensor 300 is 50% or more or 60% or more, and the number of lenses with an effective diameter smaller than the length of the image sensor 300 is less than 50% or more. It may be less than 40%.

On the optical axis OA, the first lens group LG1 and the second lens group LG2 may have a set interval. The optical axis spacing between the first lens group (LG1) and the second lens group (LG2) on the optical axis (OA) is the sensor side of the lens closest to the sensor among the lenses in the first lens group (LG1) and the second lens group ( Among the lenses in LG2), it may be the optical axis spacing between the object side of the lens closest to the object side. The optical axis interval between the first lens group (LG1) and the second lens group (LG2) may be less than 1 times the optical axis distance of the first lens group (LG1), for example, 0.1 of the optical axis distance of the first lens group (LG1). It may range from 2x to 1x.

The optical axis distance between the first lens group (LG1) and the second lens group (LG2) may be 0.2 times or less than the optical axis distance of the second lens group (LG2), for example, in the range of 0.01 to 0.2 times. The optical axis distance of the second lens group LG2 is the optical axis distance between the object side of the lens closest to the object side of the second lens group LG2 and the sensor side of the lens closest to the image sensor 300.

Here, among the lens surfaces of the first lens group (LG1) and the second lens group (LG2), two surfaces that face each other, for example, the sensor side of the object-side lens may be concave and the object-side of the sensor-side lens may be concave. That is, the sensor side closest to the sensor side in the first lens group LG1 may be concave, and the object side closest to the object side in the second lens group LG2 may be concave. Alternatively, among the lens surfaces of the first lens group (LG1) and the second lens group (LG2), two surfaces that face each other, for example, the sensor side of the object-side lens may be convex and the object-side of the sensor-side lens may be convex. That is, the sensor side closest to the sensor side in the first lens group LG1 may be convex, and the object side closest to the object side in the second lens group LG2 may be convex. The first lens group (LG1) diffuses the light incident through the object side, and the second lens group (LG2) refracts the light diffused through the first lens group (LG1) into the area of the image sensor 300. I can do it for you.

The first lens group LG1 of the optical system 1000 according to this first embodiment may have negative (-) refractive power, and the second lens group LG2 may have positive (+) refractive power. Among the lenses of the first lens group (LG1), the lens closest to the object side has negative (-) refractive power, and among the lenses of the second lens group (LG2), the lens closest to the sensor side has negative (-) refractive power. Can have refractive power. When expressing the focal length as an absolute value, the focal distance of the first lens group LG1 may be greater than the focal distance of the second lens group LG2, for example, 2 times or more, for example, 2 to 10 times the range. The effective focal length (EFL) of the optical system 1000 may be smaller than the absolute value of the focal length of the first lens group LG1. The effective focal length (EFL) of the optical system 1000 may be smaller than the absolute value of the focal distance of the first lens group (LG1) and greater than the absolute value of the focal distance of the second lens group (LG2).

The first lens group LG1 of the optical system 2000 according to this second embodiment may have positive (+) refractive power, and the second lens group LG2 may have positive (+) refractive power. Among the lenses of the first lens group (LG1), the lens closest to the object side has positive (+) refractive power, and among the lenses of the second lens group (LG2), the lens closest to the sensor side has negative (-) refractive power. Can have refractive power. When expressing the focal length as an absolute value, the focal distance of the first lens group LG1 may be greater than the focal distance of the second lens group LG2, for example, 20 times or more, for example, in the range of 20 to 50 times. The effective focal length (EFL) of the optical system 2000 may be smaller than the absolute value of the focal length of the first lens group LG1. The effective focal length (EFL) of the optical system 2000 may be smaller than the absolute value of the focal length of the second lens group LG1.

In the optical system 1000 according to the first embodiment, the number of lenses with negative (-) refractive power may be equal to or greater than the number of lenses with positive (+) refractive power. The number of lenses with negative (-) refractive power may be more than 50% of the total number of lenses. The average refractive index of lenses with negative (-) refractive power may be greater than the average of lenses with positive (+) refractive power. Accordingly, the dispersion value of lenses with positive (+) refractive power may be greater than that of lenses with negative (-) refractive power.

In the optical system 2000 according to the second embodiment, the number of lenses with positive (+) refractive power may be equal to or greater than the number of lenses with negative (-) refractive power. The number of lenses with positive refractive power may be 50% or more than the total number of lenses. The average refractive index of lenses with positive (+) refractive power may be greater than the average of lenses with negative (-) refractive power. Accordingly, the dispersion value of lenses with negative (-) refractive power may be greater than that of lenses with positive (+) refractive power.

The lens units 100 and 200 may be a mixture of glass-made lenses and plastic-made lenses. The number of lenses made of plastic may be 60% or more, 40% to 85%, or 60% to 80% of the total number of lenses. Accordingly, if more plastic lenses are placed within the camera module, the weight of the camera module can be reduced, and the plastic material makes it easy to polish and process, has strong external impact, and is highly price competitive and easy to secure materials. Additionally, various aberrations can be corrected using plastic lenses, preventing degradation of optical performance.

Embodiments of the invention can reduce the weight of the camera module by further mixing plastic lenses in the optical system (1000, 2000), provide a cheaper manufacturing cost, and prevent deterioration of optical properties due to temperature changes. Various types of plastic lenses can replace glass lenses, and polishing and processing of lens surfaces such as aspherical surfaces or free-form surfaces can be easy.

The lens units 100 and 200 may include lenses made of a first material and lenses made of a second material arranged along the optical axis OA. The first material may be glass, and the second material may be plastic. Lenses of the first material may be disposed between lenses of the second material. Lenses of the second material may be disposed between lenses of the first material.

The lens units 100 and 200 may include lenses made of a first material having an aspherical surface along the optical axis OA, lenses made of a first material having a spherical surface, and lenses made of a second material having an aspherical surface. The first material may be glass, and the second material may be plastic. A lens made of a first material having a spherical surface may be disposed between lenses made of a second material having an aspherical surface. The lens of the second material may be disposed between the lens of the first material having an aspherical surface and the lens of the first material having a spherical surface.

The effective diameter of the lens closest to the object within the lens units 100 and 200 may be larger than the effective diameter of the lens closest to the image sensor 300. Accordingly, the brightness of the optical system can be controlled. The effective diameter may be the average effective diameter of the object side and the sensor side of each lens. By controlling the effective diameter size of each lens, the optical system (1000, 2000) can control the incident light to compensate for the decrease in optical characteristics due to changes in resolution and temperature, and improve the chromatic aberration control characteristic, and the optical system (1000, 2000) can control the incident light. 2000) can improve the vignetting characteristics.

The lens units 100 and 200 include a first lens 101 and 201, a second lens 102 and 202, a third lens 103 and 203, a fourth lens 104 and 204, and a fifth lens aligned along the optical axis from the object side toward the sensor side. (105,205), a sixth lens (106,206), and a seventh lens (107,207).

The lens units 100 and 200 may be disposed in a camera module having an inner barrel on one side or the entire inner surface of the lens barrel. The lens units 100 and 200 may be disposed in a camera module having a plurality of inner barrels around different lenses of the lens barrel. The lens units 100 and 200 may be disposed in a camera module having a first inner barrel in contact with an outer surface of at least one lens of the lens barrel and a second inner barrel in contact with an outer surface of at least one lens. The lens units 100 and 200 may be disposed in a camera module having a plurality of inner barrels respectively disposed between the outside of at least one or two lenses and the lens barrel. The lens units 100 and 200 may be disposed in a camera module in which a plurality of inner barrels have a material different from that of the lens barrel.

Among the lenses constituting the lens units 100 and 200, at least some of the lenses made of glass may be placed in the lens barrel, and at least some of the lenses made of plastic may be placed in the inner barrel located within the lens barrel. Through this, the optical systems 1000 and 2000 can maintain resolution according to temperature changes. The lens units 100 and 200 are disposed in a camera module having a heterogeneous barrel to minimize decentering of a lens, such as a plastic lens, that expands according to temperature changes. The lens barrel on which the lens units 100 and 200 are disposed has a plurality of inner barrels within the lens barrel, thereby maintaining the resolution of the optical system and suppressing deformation of the lenses due to temperature changes. Accordingly, the effective diameter of at least some of the glass lenses included in the lens units 100 and 200 may be smaller than the effective diameter of at least some of the plastic lenses.

Within the lens units 100 and 200, there may be three or more lenses larger than the average effective diameter of the plastic lenses, for example, four or more lenses. The average effective diameter of plastic lenses is PLca_Aver, and if the average effective diameter of glass lenses is GLca_Aver, the condition of PLca_Aver < GLca_Aver can be satisfied. Additionally, the condition of 1 < GLca_Aver / PLca_Aver < 1.5 can be satisfied. Additionally, the relationship between the length of the image sensor 300 and the average effective diameter (PLca_Aver) of the plastic lens may satisfy the condition of 1 ≤ PLca_Aver/(Imgh*2) < 1.5. Additionally, the relationship between the average effective age of the glass material and the length of the image sensor 300 may satisfy the condition of 1.1 < GLca_Aver/(Imgh*2) < 1.5. The difference between the maximum length of the image sensor 300 and the effective diameter of the plastic lens may be arranged to be small. Accordingly, by placing a plastic lens with a small effective diameter adjacent to the image sensor 300, the plastic lenses can disperse color from the center of the image sensor 300 to the periphery.

The average effective diameter of the glass materials may be 10 mm or more, for example, in the range of 10 mm to 15 mm. The average effective diameter of the plastic material may be 8 mm or more, for example, in the range of 8 mm to 12 mm. The lens with the minimum effective diameter may be made of plastic, and the lens with the maximum effective diameter may be made of glass. Within the lens units 100 and 200, the minimum effective diameter may be in the range of 7 mm to 10 mm, and the maximum effective diameter may be in the range of 11 mm to 15 mm. Plastic lenses are designed to have a smaller effective diameter than glass lenses and are placed so as not to contact the lens barrel, thereby minimizing changes in optical performance due to temperature changes. Additionally, the optical systems 1000 and 2000 can control incident light to improve resolution and chromatic aberration control characteristics, and the vignetting characteristics of the optical systems 1000 and 2000 can be improved.

The optical systems 1000 and 2000 or the camera module may include an image sensor 300. The image sensor 300 can detect light and convert it into an electrical signal. The image sensor 300 can detect light that sequentially passes through the lens units 100 and 200. The image sensor 300 may include an element that can detect incident light, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

Here, the length of the image sensor 300 is the maximum length in the diagonal direction orthogonal to the optical axis (OA), is smaller than the effective diameter of the lens closest to the object in the first lens group (LG1), and is smaller than the effective diameter of the lens closest to the object in the first lens group (LG1). It may be larger than the effective diameter of the lens closest to the sensor. Here, the number of lenses having an effective diameter larger than the length of the image sensor 300 may be 4 to 6, and the number of lenses having an effective diameter smaller than the length of the image sensor 300 may be 1 to 3.

The optical systems 1000 and 2000 or the camera module may include a filter 500. The filter 500 may be disposed between the second lens group LG2 and the image sensor 300. The filter 500 may be disposed between the image sensor 300 and a lens closest to the sensor among the lenses of the lens units 100 and 200. For example, the filter 500 may be disposed between the nth lens and the image sensor 300.

The cover glass 400 is disposed between the filter 500 and the image sensor 300, protects the upper part of the image sensor 192, and can prevent the reliability of the image sensor 192 from deteriorating. Cover glass 400 may be removed. The cover glass 400 may be a protective glass.

The filter 500 may include an infrared filter or an infrared cut-off filter. The filter 500 may pass light in a set wavelength band and filter light in a different wavelength band. When the filter 500 includes an infrared filter, radiant heat emitted from external light can be blocked from being transmitted to the image sensor 300. Additionally, the filter 500 can transmit visible light and reflect infrared rays.

The optical systems 1000 and 2000 according to embodiments may include an aperture (Stop). The aperture can control the amount of light incident on the optical system (1000, 2000). For lenses disposed between an object and an aperture, the effective diameter of the lens surface tends to increase from the object side to the aperture. For lens surfaces disposed between the aperture and the sensor, the effective diameter of the lens surfaces tends to decrease as it moves from the aperture to the sensor. The fact that the effective diameter of the lens planes tends to increase or decrease does not mean only when the effective diameter of the lens planes increases or decreases. For example, this includes cases where the effective diameter of the lens surfaces increases and then decreases as it moves from the aperture to the sensor side.

The aperture may be placed at a set position. For example, the aperture may be disposed around the object side or sensor side of the lens closest to the object side among the lenses of the second lens group LG2. Alternatively, the aperture may be disposed around the object side or sensor side of the object side lens of the first lens group LG1. Alternatively, at least one lens selected from among the plurality of lenses may function as an aperture. In detail, the object side or the sensor side of one lens selected from among the lenses of the optical system 1000 and 2000 may function as an aperture to control the amount of light.

In the optical systems 1000 and 2000 of the embodiment, the sum of the refractive indices of the lenses of the lens units 100 and 200 may be 8 or more, for example, in the range of 8 to 15, and the average refractive index may be in the range of 1.58 to 1.7. The sum of the Abbe numbers of each lens may be 300 or more, for example, in the range of 310 to 350, and the average of the Abbe numbers may be 50 or less, for example, in the range of 35 to 47. The sum of the central thicknesses of all lenses may be 18 mm or more, for example, in the range of 20 mm to 25 mm, and the average of the central thicknesses may be in the range of 2.8 mm to 3.5 mm. The sum of the center spacings between the lenses at the optical axis (OA) may be greater than 6 mm, for example in the range of 6.8 mm to 8 mm, and less than the sum of the center thicknesses of the lenses. Additionally, the average effective diameter of each lens surface (S1-S14) of the lens units 100 and 200 may be 8 mm or more, for example, in the range of 8 mm to 15 mm.

In the optical system according to an embodiment of the invention, the angle of view (diagonal) may be 50 degrees or less, for example, in the range of 20 to 50 degrees. The F number of the optical system or camera module may be 2.4 or less, for example, in the range of 1.4 to 2.4 or 1.5 to 1.8. In the optical system according to an embodiment of the invention, the maximum angle of view (diagonal) may be 50 degrees or less, for example, in the range of 20 to 50 degrees. The horizontal field of view (FOV_H) of the vehicle optical system in the Y-axis direction may be greater than 20 degrees and less than 40 degrees, for example, in the range of 25 degrees to 35 degrees. Additionally, the vertical angle of view is provided at a smaller angle than the horizontal angle of view, and may be 20 degrees or less, for example, in the range of 10 to 20 degrees. At this time, the sensor length in the horizontal direction (Y) may be 8.064 mm ± 0.5 mm, and the sensor height in the vertical direction (X) may be 4.54 mm ± 0.5 mm. The horizontal angle of view (FOV_H) is the angle of view based on the horizontal length of the sensor. Accordingly, it is possible to suppress changes in the focus imaging position due to temperature changes, and it is possible to provide a vehicle camera in which various aberrations are well corrected.

Since the embodiment is an optical system applied to a vehicle camera, the first lenses 101 and 201 can be made of glass even though they are designed using both plastic lenses and glass lenses. This has the advantage that glass material is more resistant to scratches than plastic material and is not sensitive to external temperature. The first lenses 101 and 201 may be glass mold lenses that have an aspherical surface and are made of glass. Glass mold lenses can be produced by placing an optical glass ingot inside a mold that will have an aspherical shape and then heating and compressing it.

In order to more effectively prevent scratches placed inside the vehicle or caused by foreign substances, a glass lens is used as the first lens (101, 201), and the object side of the first lens (101, 201) has a gently curved shape to avoid contact with external structures. You can. Through this, the occurrence of scratches due to contact with external structures can be minimized. For driver monitoring when driving a vehicle, photographing the front/rear of the vehicle, or detecting lanes and unexpected objects around the vehicle, the angle of view may be greater than 20 degrees and less than 40 degrees, for example, in the range of 25 degrees to 35 degrees. This horizontal angle of view may be a preset angle for an advanced driver assistance system (ADAS).

The optical systems 1000 and 2000 according to embodiments may further include a reflection member for changing the path of light. The reflection member may be implemented as a prism that reflects incident light from the first lens group LG1 in the direction of the lenses. Hereinafter, the optical system according to the embodiment will be described in detail.

The optical system according to the first embodiment of the present invention will be described.

FIG. 1 is a side cross-sectional view of an optical system and a camera module having the same according to a first embodiment, FIG. 2 is a side cross-sectional view for explaining the relationship between the nth and n-1th lenses according to FIG. 1, and FIG. 3 is a side cross-sectional view of FIG. 1. is a table showing the lens characteristics of the optical system of , and Figure 4 is a table showing the aspheric coefficients of the lenses in the optical system of Figure 1, and Figure 5 is a table showing the thickness of each lens and the gap between adjacent lenses in the optical system of Figure 1. 6 is a table showing the Sag values of the lens surfaces of the third to sixth lenses in the optical system of Figure 1, and Figure 7 is a table showing the Chief Ray Angle (CRA) at room temperature, low temperature, and high temperature according to the position of the image sensor in the optical system of Figure 1. ) is a table showing data, and Figures 8 to 10 are graphs showing data on the diffraction MTF (Modulation Transfer Function) at room temperature, low temperature, and high temperature of the optical system of Figure 1, and Figures 11 to 13 are graphs showing data of the optical system of Figure 1 This is a graph showing data on aberration characteristics at room temperature, low temperature, and high temperature, and FIG. 14 is a graph showing relative illuminance according to the height of the image sensor according to an embodiment.

Referring to FIGS. 1 to 4 , the optical system 1000 includes a lens unit 100, and the lens unit 100 may include first to seventh lenses 101 to 107. The first to seventh lenses 101 to 107 may be sequentially arranged along the optical axis OA of the optical system 1000. Light corresponding to information on the object may pass through the first to seventh lenses 101 to 107 and the filter 500 and be incident on the image sensor 300.

The first lens 101 is the lens closest to the object in the first lens group LG1. The seventh lens 107 is the closest lens to the image sensor 107 in the second lens group LG2 or the lens unit 100. The first lens 101 and the second lens 102 may be the first lens group (LG1), and the third to seventh lenses (103, 104, 105, 106, and 107) may be the second lens group (LG2). The aperture may be disposed either around the object side or sensor side of the first lens 101, or around the object side or sensor side of the second lens 102. For example, the aperture (Stop) may be placed around the sensor side of the second lens 102.

The first lens 101 may be placed closest to the object. The first lens 101 may be placed furthest from the sensor side. The first lens 101 may have negative refractive power at the optical axis OA. The first lens 101 may include a plastic material or a glass material, for example, a glass material. The first lens 101 made of glass can reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and can protect the entrance side of the optical system 1000.

Based on the optical axis, the object-side first surface S1 of the first lens 101 may be convex, and the sensor-side second surface S2 may be concave. The first lens 101 may have a meniscus shape that is convex toward the object. The first lens 101 is made of glass and may have a spherical surface.

The effective radius r11 of the first lens 101 may be larger than the effective radius of the plastic lenses. Alternatively, at least one of the object side and the sensor side of the first lens 101 may have a free curved surface, that is, a non-rotationally symmetric curved surface.

Since the first surface (S1) is convex and the second surface (S2) is concave, incident light can be refracted in a direction away from the optical axis (OA), and the gap between the first and second lenses (101 and 102) can be reduced. I can give it. Additionally, depending on the shape of the lens surface of the first lens 101, the effective diameter of the sensor side of the second lens 102 can be designed to be smaller than the effective diameter of the object side. The first surface S1 of the first lens 101 may be provided without a critical point from the optical axis OA to the end of the effective area, that is, the edge. The second surface S2 of the first lens 101 may be provided without a critical point.

The refractive index (n1) of the first lens 101 may satisfy the condition of n1>1.7 or n1>1.75. Since the refractive index (n1) of the first lens 101 is the largest in the lens unit 100, the radius of curvature of the first and second lenses 101 and 102 can be increased, and lens manufacturing can be easy. If the refractive index (n1) of the first lens 101 is less than the condition, the lens surface must be sharply concave or convex to increase the refractive power of the first and second lenses 101 and 102. In this case, the lens manufacturing process is It is not easy, and the rate of lens defects increases and may cause a decrease in yield.

The second lens 102 may be disposed second on the object side. The second lens 102 may be placed sixth on the sensor side. The second lens 102 may be disposed between the first lens 101 and the third lens 103. The second lens 102 may have negative refractive power at the optical axis (OA). The second lens 102 may include plastic or glass. For example, the second lens 102 is made of glass and may have a spherical surface.

Based on the optical axis OA, the object-side third surface S3 of the second lens 102 may be concave, and the sensor-side fourth surface S4 may be convex. The second lens 102 may have a meniscus shape that is convex toward the sensor. The second lens 102 is made of glass and may have a spherical surface.

The aperture stop may be disposed around the fourth surface S4 on the sensor side of the second lens 102. Aperture can reduce TTL within the range of view angle, and miniaturization of the optical system is possible. Accordingly, it is possible to prevent a decrease in the yield by weight of the optical system and improve production efficiency. Additionally, the optical system can be miniaturized by reducing the TTL at a horizontal angle of view (FOV_H) of 25 to 36 degrees.

The third lens 103 may be arranged third from the object side. The third lens 103 may be placed fifth on the sensor side. The third lens 103 may be disposed between the second lens 102 and the fourth lens 104. The third lens 103 may have positive (+) refractive power at the optical axis (OA). The third lens 103 may include plastic or glass. For example, the third lens 103 may be made of glass.

Based on the optical axis, the object-side fifth surface S5 of the third lens 103 may be convex, and the sensor-side sixth surface S6 may be convex. The third lens 103 may have a shape in which both sides are convex at the optical axis OA. The third lens 103 is made of glass and may be spherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be spherical. At least one or both of the fifth surface S5 and the sixth surface S6 may be provided without a critical point from the optical axis OA to the end of the effective area. Since both sides of the third lens 103 are convex, the TTL and number of lenses of the optical system can be minimized and light can be effectively refracted.

The fourth lens 104 may be placed fourth on the object side. The fourth lens 104 may be placed fourth on the sensor side. The fourth lens 104 may be disposed between the third lens 103 and the fifth lens 105. The fourth lens 104 may have positive (+) or negative (-) refractive power at the optical axis (OA). The fourth lens 104 may have positive (+) refractive power. The fourth lens 104 may have a positive (+) refractive power that is different from that of the fifth lens 105. The fourth lens 104 may include plastic or glass. For example, the fourth lens 104 may be made of plastic. The fourth lens 104 may be made of the same material as the fifth lens 105.

Based on the optical axis, the object-side seventh surface S7 of the fourth lens 104 may be convex, and the sensor-side eighth surface S8 may be concave. The fourth lens 104 may have a meniscus shape that is convex toward the object. The fourth lens 104 is made of plastic and may have an aspherical surface. At least one or both of the seventh surface S7 and the eighth surface S8 may be aspherical. The aspherical coefficients of the seventh and eighth surfaces (S7 and S8) can be provided as S1 and S2 of L4 in FIG. 4. The seventh surface S7 and the eighth surface S8 may be provided without a critical point from the optical axis OA to the end of the effective area.

The fifth lens 105 may be placed fifth on the object side. The fifth lens 105 may be placed third on the sensor side. The fifth lens 105 may be disposed between the fourth lens 104 and the sixth lens 106. The fifth lens 105 may have positive (+) or negative (-) refractive power at the optical axis (OA). The fifth lens 105 may have negative (-) refractive power. The fifth lens 105 may have a negative (-) refractive power that is different from the refractive power of the fourth lens 104. The fifth lens 105 may include plastic or glass. For example, the fifth lens 105 may be made of plastic. The fifth lens 105 may be made of the same material as the fourth lens 104.

Based on the optical axis OA, the object-side ninth surface S9 of the fifth lens 105 may be convex, and the sensor-side tenth surface S10 may be concave. The fifth lens 105 may have a meniscus shape that is convex from the optical axis OA toward the object. The fifth lens 105 is made of plastic and may have an aspherical surface. At least one or both of the ninth surface S9 and the tenth surface S10 may be aspherical. The aspherical coefficients of the 9th and 10th surfaces (S9 and S10) can be provided as S1 and S2 of L5 in FIG. 4. The ninth surface S9 and the tenth surface S10 may be provided without a critical point from the optical axis OA to the end of the effective area.

The center spacing (CG4) of the fourth lens 104 and the fifth lens 105 may satisfy 0.05 mm to 0.2 mm, for example, 0.08 mm to 0.15 mm. In addition, the difference between the radius of curvature of the eighth surface S8 on the sensor side of the fourth lens 104 and the ninth surface on the object side of the fifth lens 105 may satisfy 2 mm to 5 mm, for example. 2.5 mm to 3.5 mm can be satisfied. Through the above conditions, the curvature radii of the sensor-side eighth surface S8 of the fourth lens 104 and the object-side ninth surface S9 of the fifth lens 105 are set to be similar, so that the curvature radius of the bonded lens within the effective diameter area is set to be similar. May have optical properties.

More specifically, the product of the refractive power of the fourth lens 104 adjacent to the object side and the refractive power of the fifth lens 105 adjacent to the sensor side may be less than 0. The product of the focal length of the fourth lens 104 adjacent to the object side and the focal length of the fifth lens 105 adjacent to the sensor side may be less than 0. Accordingly, the aberration characteristics of the optical system can be improved. If the refractive powers of the two lenses of the bonded lens 145 are the same, there is a limit to improving the aberration.

The fourth lens 104 and the fifth lens 105 are made of plastic materials with different refractive indexes, and any two consecutive lenses among the third to sixth lenses located in the middle or behind the middle within the lens unit 100 Since it is placed in , chromatic aberration correction can be more efficient.

The sixth lens 106 may be placed sixth on the object side. The sixth lens 106 may be placed second on the sensor side. The sixth lens 106 may be disposed between the fifth lens 105 and the seventh lens 107. The sixth lens 106 may have positive (+) or negative (-) refractive power at the optical axis (OA). The sixth lens 106 may have positive (+) refractive power. The sixth lens 106 may include plastic or glass. For example, the sixth lens 106 may be made of plastic.

Based on the optical axis OA, the object-side 11th surface S11 of the sixth lens 106 may be convex and the sensor-side 12th surface S12 may be concave. The sixth lens 106 may have a meniscus shape that is convex from the optical axis OA toward the object. Differently, the sixth lens 106 may have a convex shape on both sides. At least one or both of the 11th surface (S11) and the 12th surface (S12) may be aspherical. The aspherical coefficients of the 11th and 12th surfaces (S11 and S12) may be provided as L1 and L2 of L6 in FIG. 4.

The 11th surface S11 of the sixth lens 106 may be provided without a critical point from the optical axis OA to the end of the effective area. The twelfth surface S12 may be provided without at least one critical point from the optical axis OA to the end of the effective area.

The seventh lens 107 may be placed closest to the sensor side. The seventh lens 107 may be placed furthest from the object. The seventh lens 107 may have positive (+) or negative (-) refractive power at the optical axis (OA). The seventh lens 107 may have negative (-) refractive power. The seventh lens 107 may include plastic or glass. For example, the seventh lens 107 may be made of plastic.

On the optical axis, the object-side 13th surface S13 of the seventh lens 107 may be convex, and the sensor-side 14th surface S14 may be concave. The seventh lens 107 may have a meniscus shape convex toward the object. At least one of the 13th surface (S13) and the 14th surface (S14) may be an aspherical surface. For example, both the 13th surface S13 and the 14th surface S14 may be aspherical surfaces. The aspheric coefficients of the 13th and 14th surfaces (S13 and S14) may be provided as S1 and S2 of L7 in FIG. 4.

The 13th surface S13 of the seventh lens 107 may have a critical point from the optical axis OA to the end of the effective area. When the 13th surface S13 has a critical point, it may be located at more than 50% of the effective radius r71 from the optical axis OA, or may be located in the range of 52% to 70%, or 53% to 60%. When the 14th surface S14 has a critical point, it may be located at more than 70% of the effective radius r72 from the optical axis OA, or within a range of 70% to 90% or 75% to 85%.

The seventh lens 107 may be a plastic lens closest to the image sensor 300. Additionally, by arranging two or more plastic lenses adjacent to the image sensor 300, aberrations such as spherical aberration and chromatic aberration can be improved by the lens surface having an aspherical surface, and the influence on resolution can be controlled. Additionally, by placing a plastic lens as a lens adjacent to the image sensor 300, it can be insensitive to assembly tolerances compared to a lens made of glass. In other words, being insensitive to assembly tolerances means that optical performance may not be significantly affected even if the assembly is assembled with a slight difference compared to the design. In addition, by providing two lenses 106 and 107 adjacent to the image sensor 300 made of plastic, optical performance can be improved by the lens surface having an aspherical surface, for example, aberration characteristics can be improved and resolution can be prevented. .

The sixth lens 106 and the seventh lens 107 are arranged to be spaced apart, but may include features of a bonded lens. The sixth lens 106 and the seventh lens 107 may have opposite refractive powers. The product of the refractive power of the sixth lens 106 and the refractive power of the seventh lens 107 may be less than 0. The product of the focal length of the sixth lens 106 and the focal length of the seventh lens 107 may be less than 0. Accordingly, the aberration characteristics of the optical system can be improved. If the refractive powers of two lenses that have the characteristics of a bonded lens are the same, there is a limit to improving aberrations.

At least one or both of the 13th surface S13 and the 14th surface S14 of the seventh lens 107 may have a critical point. The 13th surface S13 of the seventh lens 107 may have a first critical point P1 from the optical axis OA to the end of the effective area. The first critical point P1 of the 13th surface S13 may be located at 55% or more of the effective radius from the optical axis OA, or may be located at 55% to 75% of the effective radius, or 60% to 70% of the effective radius. The first critical point of the 13th surface S13 may be located at a distance of 1.5 mm or more from the optical axis OA, for example, in the range of 1.5 mm to 2.5 mm or 1.6 mm to 2.0 mm. As another example, the 13th side S13 may be provided without a critical point. The 13th surface (S13) having this first critical point (P1) can refract incident light to the center and periphery and improve aberration. The first and second critical points (P1, P2) are the optical axis (OA) and the sign of the slope value with respect to the direction perpendicular to the optical axis (OA) is from positive (+) to negative (-) or from negative (-) to positive (+). ), which may mean a point where the slope value is 0. Additionally, the first and second critical points (P1, P2) may be points where the slope value of the tangent line passing through the lens surface decreases as the value increases, or points where it decreases and then increases.

The 14th surface S14 of the seventh lens 107 may have at least one second critical point P2 from the optical axis OA to the end of the effective area. The second critical point (P2) of the 14th surface (S14) may be located at a distance of 60% or more of the effective radius (r72) from the optical axis (OA), or may be located in the range of 60% to 80% or 65% to 75% of the effective radius (r72). there is. The second critical point P2 of the 14th surface S14 may be located at a distance of 3.0 mm or more from the optical axis OA, for example, in the range of 2.9 mm to 3.9 mm or 3.1 mm to 3.7 mm. Accordingly, the second critical point P2 is disposed closer to the edge than the first critical point P1, so that the seventh lens 107 can refract the incident light to the periphery of the image sensor 300.

The average effective radius of the 13th and 14th surfaces (S13, S14) of the seventh lens 107 is arranged to be smaller than Imgh, which is 1/2 of the diagonal length of the image sensor 300, which has a second critical point (P2). Light can be refracted to the periphery of the image sensor 300 by the fourteenth surface S14.

1 and 2, the center thickness of the first to seventh lenses 101 to 107 is indicated by CT1 to CT7, and the edge thickness, which is the end of the effective area of each lens, is indicated by ET1 to ET7, and the thickness between the two adjacent lenses is indicated by CT1 to CT7. The center gap is indicated by CG1~CG6, and the edge gap between the edges of each lens is indicated by EG1~EG6.

Referring to FIG. 2, back focal length (BFL) is the optical axis distance from the image sensor 300 to the center of the last lens. In FIG. 1, TTL is the optical axis distance from the center of the first surface S1 of the first lens 101 to the upper surface of the image sensor 300.

Figure 3 is an example of lens data of the optical system of the embodiment of Figure 1. As shown in Figure 3, the radius of curvature at the optical axis (OA) of the first to seventh lenses (101, 102, 103, 104, 105, 106, 107), the thickness of the lens, the center distance between the lenses, d-line You can set the size of the refractive index, Abbe's Number, and clear aperture (CA).

As shown in FIG. 4 , in the embodiment, the lens surfaces of the fourth, fifth, sixth, and seventh lenses (104, 105, 106, and 107) among the lenses of the lens unit 100 may include an aspherical surface with a 30th order aspheric coefficient. For example, the fourth, fifth, sixth, and seventh lenses 104, 105, 106, and 107 may include lens surfaces having a 30th order aspherical coefficient. As described above, an aspheric surface with a 30th order aspheric coefficient (a value other than “0”) can particularly significantly change the shape of the aspherical surface in the peripheral area, so the optical performance of the peripheral area of the field of view (FOV) can be well corrected.

As shown in Figure 5, the thickness (T1-T7) of the first to seventh lenses (101, 102, 103, 104, 105, 106, and 107) and the gap (G1-G6) between two adjacent lenses can be set. As shown in Figure 5, in the Y-axis direction, the thickness of each lens (T1-T7) can be expressed at intervals of 0.1mm or 0.2mm or more, and the interval between each lens (G1-G6) can be expressed at intervals of 0.1mm or 0.2mm or more. It can be displayed every time.

3 and 5, when comparing the absolute values of the radii of curvature of each lens, the radius of curvature of the 12th surface S12 of the sixth lens 106 at the optical axis OA is the largest among the lenses, and 5 The radius of curvature of the tenth surface (S10) of the lens 105 may be the smallest among the lenses. The difference between the maximum radius of curvature and the minimum radius of curvature may be in the range of 10 times or more, for example, 15 to 20 times.

When explaining the central thickness of the lens based on the optical axis, the central thickness (CT2) of the second lens 102 is the largest among the lenses, and the central thickness (CT1) of the first lens 101 is the smallest among the lenses. The difference between the maximum and minimum center thickness of the lens may be in the range of 3.5 mm or more and 5.5 mm or less.

Describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens 101 and the second lens 102 is the maximum, and the center spacing between the second and third lenses (102 and 103) is ( CG2), the center spacing (CG3) between the third and fourth lenses 103 and 104, and the center spacing (CG5) between the fourth and fifth lenses 104 and 105 may be minimal. The difference between the maximum center spacing and the minimum center spacing among the spaced apart lenses may be 3 mm or more, for example, in the range of 3 mm to 5 mm.

Regarding the effective diameter, a lens with the maximum effective diameter may be disposed between the first lens 101 closest to the object and the seventh lens 107 closest to the image sensor 300. The lens having the maximum effective diameter may be a glass lens. The lens having the maximum effective diameter may be the third lens 103. Here, the effective diameter is the average of the effective diameter of each lens on the object side and the effective diameter on the sensor side. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens 101 or the first surface (S1) of the first lens 101.

The lens having the minimum effective diameter may be any one of plastic lenses, for example, the seventh lens 107 adjacent to the image sensor 300. For example, the effective diameter of the seventh lens 107 may be the minimum within the lens unit 100. The lens surface having the minimum effective diameter may be the 13th surface (S13) of the 7th lens 107.

The effective diameter of each of the first to fourth lenses (101-104) adjacent to the object side may be larger than the effective diameter of the fifth, sixth, and seventh lenses (105, 106, and 107) adjacent to the sensor side. The effective diameters of the first to fourth lenses 101 - 104 may be larger than the diagonal length of the image sensor 300 . The average effective diameter of the seventh lens 107 may be smaller than the diagonal length of the image sensor 300. Accordingly, light incident through a plurality of lenses aligned along the optical axis can be guided to the image sensor 300.

When explaining the refractive index, the refractive index of the first lens 101 is the highest among the lenses and may be greater than 1.72, for example, greater than 1.75. Either or both of the second lens 102 and the sixth lens 106 may have the lowest refractive index among the lenses. For example, it may be less than 1.6, such as less than 1.55. The difference between the maximum and minimum refractive indices may be 0.2 or more. By providing a high refractive index lens made of glass closest to the object, and providing a low refractive index lens made of plastic for the lens adjacent to the glass lens and the lens adjacent to the image sensor 300, incident efficiency is increased, and the lens adjacent to the glass material lens and the lens adjacent to the image sensor 300 are provided as low refractive index lenses made of plastic. It is possible to guide the image sensor 300 by adjusting the refractive power between the lenses.

Comparing the Abbe number, the Abbe number of the third lens 103 is the largest among the lenses and may be 60 or more. The Abbe number of the fifth lens 105 and the seventh lens 107 is the minimum among the lenses and may be 25 or less. The difference between the maximum refractive index and the minimum Abbe number may be 40 or more. By providing the largest Abbe number of the third lens 103 adjacent to the center of the optical system 1000 and the smallest Abbe number of the seventh lens 107 with a low refractive index adjacent to the image sensor 300, the glass material It is possible to adjust the color dispersion of light traveling between the lenses and guide it to the image sensor 300 by increasing the color dispersion between the lenses made of glass and plastic.

The focal lengths F1, F2, F5, and F7 of the first, second, fifth, and seventh lenses 101, 102, 105, and 107 may have a negative (-) sign. The first, second, fifth, and seventh lenses (101, 102, 105, and 107) may have negative refractive power. The focal lengths F3, F4, and F6 of the third, fourth, and sixth lenses 103, 104, and 106 may have a positive (+) sign. The third, fourth, and sixth lenses (103, 104, and 106) may have positive refractive power. Third and fourth lenses 103 and 104 having positive (+) refractive power may be disposed on the sensor side of the first and second lenses 101 and 102 having negative (-) refractive power. Through this, the light incident from the object side can move away from the optical axis direction and then converge again in the optical axis direction, forming a stable optical path.

Additionally, the lenses disposed adjacently, such as the fourth lens 104, fifth lens 105, sixth lens 106, and seventh lens 107, may satisfy the following conditions.

Condition 1: Refractive index of a lens with positive refractive power < Refractive index of a lens with negative refractive power

Condition 2: Dispersion value of a lens with positive refractive power > Dispersion value of a lens with negative refractive power

Here, among the plastic lenses, the fourth lens 104 and the sixth lens 106 have positive refractive power, and the fifth lens 105 and the seventh lens 107 have negative refractive power, so condition 1 According to ,2, the refractive index of the fourth lens is smaller than the refractive index of the fifth lens, and the dispersion value of the fourth lens is greater than the dispersion value of the fifth lens. Additionally, the refractive index of the sixth lens is smaller than that of the seventh lens, and the dispersion value of the sixth lens is greater than that of the seventh lens. Chromatic aberration occurring in plastic lenses can be corrected with plastic lenses. In addition, the fourth lens 104, the fifth lens 105, the sixth lens 106, and the seventh lens 107, which are plastic lenses arranged in series, have a refractive index difference of 0.1 or more and 0.15 or less, and an Abbe number difference of 20 or more and 60. Chromatic aberration occurring in plastic lenses can be compensated for by satisfying the following.

Optical systems produce chromatic aberration, and chromatic aberration is corrected using a bonded lens or two lenses placed in series. As the temperature changes from low to high, the lens repeats contraction and expansion. Since lenses made of the same material have the same amount of change in lens characteristics due to temperature changes, it is effective to correct chromatic aberration between lenses made of the same material even if the temperature changes.

Therefore, in an embodiment of the present invention, the fourth lens 104 and the fifth lens 105, and the sixth lens 106 and the seventh lens 107 are used to correct chromatic aberration occurring in the plastic lens.

When comparing focal lengths in absolute values, the focal length of the second lens 102 is the largest among the lenses and may be 500 or more or 600 or more. Among the lenses, the second lens 102 made of glass may have the largest focal length and the smallest refractive power. Among the lenses, the lens with the next largest focal length after the second lens 102 may be the first lens 101 made of glass. The focal length of the sixth lens 106 is the smallest among the lenses and may be 15 or less or 13 or less. Among the lenses, the sixth lens 106, which is made of plastic, may have the smallest focal length and the highest refractive power. Since lenses made of plastic material with low refractive power are disposed on the sensor side of the sixth lens 106, the refractive power of the fifth lens 105 can be increased.

The difference between the maximum and minimum focus distances may be 100 or more or 200 or more. Accordingly, it is possible to have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the field of view range set in the optical system, and good optical performance in the periphery of the field of view.

There is a critical point on the sensor side of the seventh lens (107). The critical point is the point at which the trend of the sag value changes. In other words, it is the point where the sag value increases and then decreases, or the point where the sag value decreases and then increases. Referring to FIG. 6, it can be seen that the object side of the seventh lens 107 has a critical point between a point 1.7 mm apart and a point 2.0 mm apart in the direction perpendicular to the optical axis. The sag value of the object side of the seventh lens (107) increases to a point 1.7 mm apart in the direction perpendicular to the optical axis, and then decreases as it goes from a point 1.7 mm apart to a point 4.5 mm apart in the direction perpendicular to the optical axis. I'm doing it.

It can be seen that the sensor side of the seventh lens 107 has a critical point between a point 3.3 mm apart and a point 3.9 mm apart in the direction perpendicular to the optical axis. On the sensor side of the seventh lens (107), the sag value increases to a point 3.3 mm apart in the direction perpendicular to the optical axis, and then decreases as it goes from a point 3.3 mm apart to a point 4.8 mm apart in the direction perpendicular to the optical axis. I'm doing it. If a critical point exists on the sensor side of the seventh lens (107), that is, the sensor side of the last lens, that is, the lens side closest to the sensor, the TTL can be reduced, making it easy to miniaturize and lighten the optical system.

The thickness T1 of the first lens 101 may have a difference between the maximum thickness and the minimum thickness of 1 times or more, for example, 1 to 1.2 times, the center thickness (CT1) is the minimum, and the edge thickness (ET1) is the minimum. It can be maximum. The thickness T2 of the second lens 102 may have a maximum thickness ranging from 1 to 1.2 times the minimum thickness. The second lens 102 may have a minimum center thickness (CT2) and a maximum edge thickness (ET2). The thickness T3 of the third lens 103 may be maximum at the center and minimum at the edge, with the maximum thickness being in the range of 1.5 to 2 times the minimum thickness. The thickness T4 of the fourth lens 104 may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.2 times the minimum thickness. The thickness T5 of the fifth lens 105 may be minimum at the center and maximum at the edge, with the maximum thickness ranging from 1 to 1.3 times the minimum thickness. The thickness T6 of the sixth lens 106 may be maximum at the center and minimum at the edge, with the maximum thickness being in the range of 1.5 to 2 times the minimum thickness. The thickness T7 of the seventh lens 107 may be minimum at the center and maximum at the edge, with the maximum thickness being in the range of 1.2 to 1.5 times the minimum thickness.

Among the intervals G1-G6 between the lenses, the first interval G1 between the first and second lenses 101 and 102 may be maximum at the center and minimum at the edges. The second gap G2 between the second and third lenses 102 and 103 may be maximum at the edge and minimum at the center. The third gap G3 between the third and fourth lenses 103 and 104 may be maximum at the edge and minimum at the center. The fifth gap G5 between the fifth and sixth lenses 105 and 106 may be maximum at the center and minimum at the edges. The sixth gap G6 between the sixth and seventh lenses 106 and 107 may be maximum at the center and minimum at the edges.

As shown in FIG. 7, the chief ray angle (CRA) in the optical system and camera module of FIG. 1 is 10 degrees or more in the 1-field, which is the end of the diagonal length of the image sensor, for example, in the range of 10 to 35 degrees or 10 degrees. It may range from degrees to 25 degrees. Additionally, the angle difference of the main ray from low temperature (-40 degrees) to high temperature (95 degrees) may be less than 1 degree. Accordingly, even if the temperature changes from low to high, the difference in the angle of the main ray is not large and stable optical performance can be achieved.

14 is a graph showing the peripheral light ratio or relative illumination according to the image height in the optical system according to the embodiment, where the peripheral light ratio is 70% or more, for example, 75% or more from the center of the image sensor to the end of the diagonal. You can see that it appears. In other words, it can be seen that there is almost no difference in ambient illuminance (Zoom positions 1, 2, 3) depending on room temperature, low temperature, and high temperature up to 4.5 mm or more from the optical axis.

Figures 8 to 10 are graphs showing diffraction MTF (modulation transfer function) at room temperature, low temperature, and high temperature in the optical system of Figure 1, and are graphs showing luminance ratio (modulation) according to spatial frequency. . 8 to 10, in an embodiment of the invention, the deviation of MTF from low or high temperature based on room temperature may be less than 10%, that is, 7% or less.

Figures 11 and 12 are graphs showing aberration characteristics at room temperature, low temperature, and high temperature in the optical system of Figure 1. 11 to 13 are graphs measuring spherical aberration, astigmatic field curves, and distortion from left to right. 11 to 13, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. In addition, 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 wavelength band of about 546 nm. . In the aberration diagrams of FIGS. 11 to 13, it can be interpreted that the closer each curve at room temperature, low temperature, and high temperature is to the Y axis, the better the aberration correction function is. The optical system 1000 according to the embodiment has an aberration correction function in most areas. You can see that the measured values are adjacent to the Y axis. That is, the optical system 1000 according to the embodiment has improved resolution and can have good optical performance not only in the center but also in the periphery of the field of view (FOV). Here, the low temperature is -20 degrees or lower, for example, in the range of -20 to -40 degrees, the room temperature is in the range of 22 degrees ± 5 degrees or 18 to 27 degrees, and the high temperature is 85 degrees or higher, for example, in the range of 85 to 105 degrees. It can be. Accordingly, it can be seen that the decrease in luminance ratio (modulation) from the low temperature to the high temperature in FIGS. 11 to 13 is less than 10%, for example, 5% or less, or is almost unchanged.

Table 1 compares the changes in optical properties such as EFL, BFL, F number (F#), TTL, and angle of view (FO)V at room temperature, low temperature, and high temperature in the optical system according to the example, and the optical characteristics at low temperature based on room temperature. It can be seen that the change rate of the properties is 5% or less, for example, 3% or less, and the change rate of the optical properties at low temperatures based on room temperature is 5% or less, for example, 3% or less.

room temperature low temperature High temperature Low temperature/room temperature High temperature/room temperature EFL(F) 15.1000 15.0068 15.2112 99.38% 100.73% BFL 2.8222 2.8187 2.8262 99.87% 100.14% F# 1.6000 1.5900 1.6119 99.37% 100.74% TTL 39.1026 39.0211 39.1984 99.79% 100.24% FOV 34.3447 34.5599 34.0947 100.62% 99.27%

Therefore, as shown in Table 1, the change in optical properties according to the temperature change from low to high temperature, for example, the rate of change in effective focal length (EFL), TTL, BFL, F number, and angle of view (FOV) is 10% or less, that is, It can be seen that it is in the range of 5% or less, for example, 0 to 5%. Even if at least one or two plastic lenses are used, temperature compensation for the plastic lenses is designed to prevent deterioration in the reliability of optical characteristics.

The optical system of the embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only in the center but also in the periphery of the field of view (FOV).

The optical system 1000 according to the embodiment disclosed above may satisfy at least one or two of the equations described below. Accordingly, the optical system 1000 according to the embodiment may have improved optical characteristics. For example, when the optical system 1000 satisfies at least one mathematical equation, the optical system 1000 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and provides good optics not only in the center but also in the periphery of the field of view (FOV). performance can be achieved. Additionally, the optical system 1000 may have improved resolution. In addition, the meaning of the thickness of the lens at the optical axis (OA) and the distance between the adjacent lenses at the optical axis (OA) described in the equations may refer to the embodiment disclosed above.

[Equation 1]

0.5 < CT1 / ET1 < 1

In Equation 1, CT1 is the center thickness of the first lens 101, and ET1 is the edge thickness of the first lens 101. Through this, factors affecting the angle of view of the optical system can be set, and factors affecting the effective focal length (EFL) can be set, and preferably 0.6 ≤ CT1 / ET1 < 1 can be satisfied.

[Equation 2]

0.1 < CT1/CA_L1S1 < 0.3

In Equation 2, CT1 is the central thickness of the first lens 101, and CA_L1S1 is the effective diameter (CA_L1S1) of the object side S1 of the first lens 101. When Equation 2 is satisfied, it is possible to prevent deterioration of the strength and optical properties of an injection molded lens made of glass. If it is lower than the range of Equation 2, the lens may be damaged or injection molding is difficult, and if it is larger than the range, the TTL may increase and the weight of the optical system may become heavy. Preferably, 0.12 < CT1/CA_L1S1 < 0.2 may be satisfied.

[Equation 3]

Po1 < 0

In Equation 3, Po1 means the sign of the refractive power of the first lens 101. For the performance of the optical system, the optical system can be set to have a shorter effective focal length compared to TTL. If Equation 3 is satisfied, the light incident from the object side to the first lens 101 can be spread in a direction away from the optical axis. The entire optical system can have a stable structure that spreads and collects light.

[Equation 3-1]

F6*F7 < 0

In Equation 3-1, F6 is the focal length of the sixth lens 106, and F7 is the focal length of the seventh lens 107. Through the conditions of Equation 3-1, the product of the focal lengths of the plastic lenses can be arranged by mixing negative (-) and positive (+) refractive powers to compensate for each other. Accordingly, aberrations occurring in plastic lenses can be mutually canceled out.

[Equation 4]

1.7 < n1 < 2.2

In Equation 4, n1 is the refractive index at the d-line of the first lens 101. Equation 4 sets the refractive index of the first lens high, so that factors affecting the reduction of third-order aberration (Seidel aberration) of the optical system can be adjusted, and aberrations that may occur as the TTL becomes somewhat longer can be reduced. Equation 4 preferably satisfies 1.75 < n1 < 2.1. If it is designed lower than the lower limit of Equation 4, it may not be effective in reducing aberrations, and the power of the first lens 101 may be weakened so that light cannot be collected efficiently, and the performance of the optical system may deteriorate. If it is designed higher than the upper limit of Equation 4, there is a disadvantage in that it becomes difficult to obtain materials. In addition, when the refractive index of the first lens 101 is designed to be lower than the lower limit of Equation 4, the radius of curvature of the first and second lenses 101 and 102 must be increased in order to increase the refractive power of the first and second lenses 101 and 102. In this case, lens production becomes more difficult, the lens defect rate increases, and yield may decrease.

[Equation 4-1]

1.6 ≤ Aver(n1:n7) ≤ 1.7

In Equation 4-1, Aver(n1:n7) is the average of the refractive index values in the d-line of the first to seventh lenses 101 to 107. When the optical system 1000 according to the embodiment satisfies Equation 4-1, the optical system 1000 can set the resolution and suppress the influence on TTL.

[Equation 5]

27 < FOV_H < 33

In Equation 5, FOV_H represents the horizontal angle of view, and the range of the vehicle optical system can be set. Equation 5 preferably satisfies 28 ≤ FOV_H ≤ 31 or satisfies the range of 29.9 degrees ± 3 degrees, and in this case, the sensor length in the horizontal direction is based on 8.064 mm ± 0.5 mm. In addition, when Equation 5 is satisfied, when the temperature changes from room temperature to high, the rate of change of the effective focal distance and the change rate of the angle of view can be set to 5% or less, for example, 0 to 5%. In addition, even if two or more plastic lenses, for example, three or more pieces, are mixed and used in the optical system 1000, degradation of optical characteristics can be prevented through temperature compensation of the plastic lenses.

[Equation 6]

L3R1 > 0

L3R2 < 0

In Equation 6, L3R1 is the radius of curvature of the object side of the third lens 103, and L3R2 is the radius of curvature of the sensor side of the third lens 103. The third lens 103 may have a convex shape on both sides. Since the third lens 103 has a convex shape on both sides, light can be refracted so that the effective diameter of the fourth to seventh lenses 104, 105, 106, and 107 disposed on the sensor side of the third lens 103 is not increased, and the number of lenses can be increased. can reduce.

[Equation 7]

1 < L7S2_max_sag to Sensor < 3

In Equation 7, L7S2_max_sag to Sensor means the straight line distance from the maximum Sag value of the seventh lens 107 to the image sensor 300. If this is satisfied, the TTL can be reduced and conditions for manufacturing the camera module can be set. Additionally, L7S2_max_sag to Sensor can set a space where the filter 500 and cover glass 400 located between the image sensor 300 and the seventh lens 107 can be placed. If the range of Equation 7 is smaller than the lower limit, the space for placing circuit structures such as filters and image sensors becomes limited, making the process of assembling circuit structures such as filters and image sensors into the optical system difficult. If the range of Equation 7 is larger than the upper limit, the process of assembling circuit structures such as filters and image sensors into the optical system is easy, but the TTL becomes longer, making miniaturization of the optical system difficult.

That is, Equation 7 can set the minimum distance between the image sensor 300 and the last lens, and preferably satisfies 1 < L7S2_max_sag to Sensor ≤ BFL. Additionally, if there is no point (P2) where the last lens protrudes further toward the image sensor than the center of the sensor side, the value of Equation 7 may be equal to the back focal length (BFL). BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens. In detail, if 1.5 < L7S2_max_sag to Sensor < 2.6 is satisfied, it is easier to manufacture and reduce TTL.

[Equation 8]

0 < CT1 / CT7 < 1

In Equation 8, CT1 is the central thickness of the first lens 101, and CT7 is the central thickness of the seventh lens 107. If Equation 8 is satisfied, the aberration characteristics can be improved and the influence on the reduction of the optical system can be set. Equation 8 preferably satisfies 0 < CT1 / CT7 < 1. Equation 8 sets the object-side lens and sensor-side lens of the optical system to a glass lens and a plastic lens, and can limit the difference in center thickness between them. Accordingly, chromatic aberration of the optical system can be improved, good optical performance can be achieved at a set angle of view, and TTL (total track length) can be controlled.

[Equation 9]

0 < CA_L1S1 / CA_L4S1 < 2

In Equation 9, CA_L1S1 means the effective diameter of the first surface (S1) of the first lens 101, and CA_L4S1 means the effective diameter of the seventh surface (S7) of the fourth lens 104. The lens barrel on which the lens unit 100 is disposed has at least one inner barrel within the lens barrel, and at least some of the plastic lenses included in the lens unit 100 may be disposed in the inner barrel. In the case of plastic lenses, the amount of expansion is large at high temperatures, so more space is required within the lens barrel. Therefore, if Equation 9, which sets the relationship between the effective diameter of the first lens 101 made of glass and the effective diameter of the fourth lens 104 made of plastic, is satisfied, the deterioration of optical properties due to temperature changes can be suppressed. The optical system 1000 can control incident light and set factors affecting aberration. Equation 9 may preferably satisfy 1 < CA_L1S1 / CA_L4S1 < 2.

[Equation 10]

0 < CA_L7S2 / CA_L5S2 < 2

In Equation 10, CA_L5S2 means the effective diameter of the 10th surface (S10) of the fifth lens 105, and CA_L7S2 means the effective diameter of the 14th surface (S14) of the seventh lens 107. If Equation 10 is satisfied, the optical system 1000 can control the incident light path and set factors for performance change according to CRA and temperature. Preferably, Equation 10 may satisfy 0.5 < CA_L7S2 / CA_L5S2 < 1.

[Equation 11]

0 < CA_L1S2 / CA_L2S1 < 2

In Equation 11, CA_L1S2 means the effective diameter of the second surface (S2) of the first lens 101, and CA_L2S1 means the effective diameter of the third surface (S3) of the second lens 102. If Equation 11 is satisfied, the optical system 1000 can control light traveling to the first lens group (LG1) and the second lens group (LG2) and set factors that affect reduction of lens sensitivity. Equation 11 may preferably satisfy 0.5 < CA_L1S2 / CA_L2S1 < 1.5.

[Equation 12]

0.5 < CA_L4S1 / CA_L5S2 < 2

In Equation 12, CA_L4S1 means the effective diameter of the 7th surface (S7) of the fourth lens 104, and CA_L5S2 means the effective diameter of the 10th surface (S10) of the fifth lens 105. If the optical system 1000 satisfies Equation 12, the size of the bonded lens disposed on the object side of the plastic lens(s) can be set. Equation 12 may preferably satisfy 1 ≤ CA_L4S1 / CA_L5S2 < 1.5.

[Equation 13]

2 < L3R1 / (CA_L3S1/2) < 5

In Equation 13, L3R1 is the radius of curvature of the object side of the third lens 103, and CA_L3S1 means the effective diameter of the object side fifth surface S5 of the third lens 103. When the third lens 103, which is convex on both sides, satisfies Equation 13, the optical system 1000 can improve chromatic aberration. If it is less than the lower limit value of Equation 13, the occurrence of aberration by the fifth surface (S5) increases, and if it is larger than the upper limit value, the occurrence of aberration by the fifth surface (S5) decreases, but the occurrence of aberration by the sixth surface (S6) increases. Since the radius of curvature must be smaller, the occurrence of aberrations increases on the sixth surface S6, which has a problem affecting the aberrations of the fourth to seventh lenses 104 to 107. Preferably, if the range 3 < L3R1 / (CA_L3S1/2) < 5 is satisfied, the aberration occurring in the fifth surface (S5) can be reduced while the curvature radius of the sixth surface (S6) can be designed to be large, so that the third lens ( 103) Easy to manufacture. Aberrations occurring in the optical system can be reduced, manufacturing of the third lens 103 can be made easier, and yield can be increased.

[Equation 13-1] CA_L4 > CA_L5 > CA_L6 > CA_L7

[Equation 13-2] CA_L7S1 < (Imgh*2)

In Equations 13-1 to 15-2, CA_L4, CA_L5, CA_L6, and CA_L7 are the effective diameters (average effective diameters) of the fourth to seventh lenses 104-107, and Imgh is 1/2 of the diagonal length of the image sensor 300. am. Accordingly, an optical path can be set from the fourth lens 104 to the area of the image sensor 300 according to the effective diameter of the seventh lens 107. The 6th and 7th lenses 106 and 107 are plastic lenses and have an aspherical surface, and the 4th and 5th lenses 104 and 105 are glass lenses and have a spherical surface, so aberrations between the lenses can be mutually compensated.

[Equation 14]

1 < CA_GL_AVER/CA_PL_AVER < 1.5

In Equation 14, CA_GL_AVER represents the average effective diameter of glass lenses, and CA_PL_AVER represents the average effective diameter of plastic lenses. The lens barrel on which the lens unit 100 is disposed has at least one inner barrel within the lens barrel, and at least some of the plastic lenses included in the lens unit 100 may be disposed in the inner barrel. In the case of plastic lenses, the amount of expansion is large at high temperatures, so more space is required within the lens barrel. By setting the effective diameter size of the glass lens and the effective diameter size of the plastic lens in Equation 14, deterioration of optical characteristics due to temperature changes can be suppressed, and the optical system 1000 can control the incident light and affect aberration. You can set the given element. Equation 14 may preferably satisfy 1.1 < CA_GL_AVER/CA_PL_AVER < 1.3.

Here, nGL < nPL can be satisfied. nGL is the number of glass lenses, and nPL is the number of plastic lenses. Additionally, the condition nPL - nGL = 0 or 1 can be satisfied.

[Equation 15]

1.2 ≤ GL_CA1_AVER/PL_CA1_AVER ≤ 1.5

In Equation 15, GL_CA1_AVER is the average of the effective diameters of the object sides of the glass lenses, for example, the average of the effective diameters of the object sides of the first, second, and third lenses (101, 102, and 103). PL_CA1_AVER is the average effective diameter of the object sides of the plastic lenses, for example, the average effective diameter of the object sides of the fourth to seventh lenses 104, 105, 106, and 107. The lens barrel on which the lens unit 100 is disposed has at least one inner barrel within the lens barrel, and at least some of the plastic lenses included in the lens unit 100 may be disposed in the inner barrel. In the case of plastic lenses, the amount of expansion is large at high temperatures, so more space is required within the lens barrel. By setting the effective diameter size of the glass lens and the effective diameter size of the plastic lens in Equation 15, deterioration of optical characteristics due to temperature changes can be suppressed, and the optical system 1000 can control the incident light and affect aberration. You can set the given element. Equation 15 may preferably satisfy 1.2 ≤ GL_CA1_AVER/PL_CA1_AVER ≤ 1.3.

[Equation 16]

CG3 < CG5 < CG1

In Equation 16, CG1 is the center spacing between the first and second lenses (101 and 102), CG3 is the center spacing between the third and fourth lenses (103 and 104), and CG5 is the center spacing between the fifth and sixth lenses (105 and 106). It can be. If Equation 16 is satisfied, the center spacing between relatively thick glass lenses can be reduced, thereby reducing TTL and improving optical performance in the peripheral area of the field of view (FOV).

[Equation 17]

1 < CT7 / CG6 < 3

In Equation 17, CG6 is the center spacing or optical axis distance between the 6th and 7th lenses 106 and 107. In Equation 17, by setting the center thickness (CT7) of the seventh lens 107 and the center distance between the sixth and seventh lenses, optical performance can be improved at the periphery of the angle of view. Equation 17 may preferably satisfy 1.5 < CT7/CG6 < 2.

[Equation 18]

3 < CT2/CT1 < 5

In Equation 18, CT1 is the central thickness of the first lens 101, and CT2 is the central thickness of the second lens 102. In Equation 18, by setting the center thickness (CT2) of the second lens to be thicker than the center thickness (CT1) of the first lens, factors affecting aberration can be controlled. Preferably, Equation 18 may satisfy 3 < CT2/CT1 < 4.

[Equation 19]

10 < L7R1 / CT7 < 20

In Equation 19, L7R1 is the radius of curvature of the 13th surface S13 of the seventh lens 107, and CT7 is the central thickness of the seventh lens 107. In Equation 19, the radius of curvature (L7R1) of the object side of the seventh lens 107 and the central thickness of the seventh lens 107 are set to control the refractive power of the seventh lens 107. Accordingly, good optical performance can be achieved in the center and periphery of the angle of view. Preferably, Equation 19 may satisfy 10 < L7R1 / CT7 < 16.

[Equation 20]

1 < CT_Max / CG_Max < 2

In Equation 20, CT_Max is the maximum central thickness among the lenses, and CG_Max is the maximum spacing between adjacent lenses. If Equation 20 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view and can reduce TTL. Preferably, 1 < CT_Max / CG_Max < 1.5 may be satisfied.

[Equation 21]

2 < ΣCT / ΣCG < 3

In Equation 21, ΣCT is the sum of the central thicknesses of the lenses, and ΣCG is the sum of the spacing between adjacent lenses. If Equation 21 is satisfied, the optical system can have good optical performance at the focal distance at the set angle of view and can reduce TTL. Preferably, 2.5 < ΣCT / ΣCG < 3 may be satisfied.

[Equation 22]

10 < ΣIndex < 20

In Equation 22, ΣIndex means the sum of the refractive indices at the d-line of each of the plurality of lenses. If Equation 22 is satisfied, TTL can be controlled in the optical system 1000 where a plastic lens and a glass lens are mixed, and improved resolution can be achieved. Additionally, when the number of lenses made of glass is greater than the number of lenses made of plastic, or if the number of lenses made of glass with a relatively thick thickness is greater, the sum of TTL and refractive index can be set. Equation 22 can preferably be satisfied as 10 <ΣIndex< 15.

[Equation 23]

10 < ΣAbb / ΣIndex < 35

In Equation 23, ΣAbb means the sum of Abbe's numbers of each of the plurality of lenses. When Equation 23 is satisfied, the optical system 1000 can have improved aberration characteristics and resolution. By setting Equation 23 to the sum of the Abbe numbers and refractive indices of the lenses, optical characteristics can be controlled, and preferably 10 < ΣAbb / ΣIndex < 30.

[Equation 24]

1 < ΣCT / ΣET < 2

In Equation 24, ΣCT is the sum of the center thicknesses of the lenses, and ΣET is the end of the effective area of the lenses, that is, the sum of the edge thicknesses. If Equation 24 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view and can reduce TTL. Equation 24 may preferably satisfy 1 < ΣCT / ΣET < 1.5.

[Equation 25]

0.5 < CA_L3S1 / CA_min < 2

In Equation 25, CA_L3S1 is the effective diameter of the object-side fifth surface S5 of the third lens 103, and CA_Min represents the minimum effective diameter among the object sides and sensor sides of the lenses. If Equation 25 is satisfied, the optical system can control incident light, maintain optical performance, and provide a slimmer module. Equation 25 may preferably satisfy 1 < CA_L3S1 / CA_min < 2.

[Equation 26]

1 < CA_max / CA_min < 3

In Equation 26, CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses, and CA_Min represents the minimum effective diameter among the object sides and sensor sides of the lenses. If Equation 26 is satisfied, the optical system can maintain optical performance and set the size for a slim and compact structure. Equation 26 may preferably satisfy 1 < CA_max / CA_min < 2.

[Equation 27]

1 < CA_max / CA_Aver < 3

In Equation 27, CA_max represents the maximum effective diameter of the object sides and sensor sides of the lenses, and CA_Aver represents the average of the effective diameters of the object sides and sensor sides of the lenses. If Equation 27 is satisfied, the optical system can maintain optical performance and set the size for a slim and compact structure. Equation 27 may preferably satisfy 1 < CA_max / CA_Aver < 1.5.

[Equation 28]

0.5 < CA_min / CA_Aver < 2

In Equation 28, CA_Min represents the minimum effective diameter among the object sides and sensor sides of the lenses, and CA_Aver represents the average of the effective diameters of the object sides and sensor sides of the lenses. If Equation 28 is satisfied, the optical system can maintain optical performance and set a size for a slim and compact structure. Equation 28 may preferably satisfy 0.5 < CA_min / CA_Aver < 1.

[Equation 29]

1 < CA_max / (2*ImgH) < 3

In Equation 29, CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses, and ImgH represents the distance from the optical axis to the diagonal end of the image sensor or 1/2 of the maximum diagonal length. If Equation 29 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. Equation 29 may preferably satisfy 1 < CA_max / (2*ImgH) < 2.

[Equation 30]

1 < TD / CA_max < 4

In Equation 30, TD is the optical axis distance from the center of the object side of the first lens 101 to the center of the sensor side of the last lens, and CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses. If Equation 30 is satisfied, the total optical axis distance and maximum effective diameter of the lenses can be set, and the size for good optical performance can be set. Equation 30 may preferably satisfy 2 < TD / CA_max < 3.

[Equation 31]

0 < F / L1R1 < 2

In Equation 31, F is the effective focal length of the optical system, and L1R1 is the radius of curvature of the object side of the first lens 101. If Equation 31 is satisfied, the influence on incident light and TTL can be adjusted. Equation 31 may preferably satisfy 0.5 ≤ F / L1R1 < 1.

[Equation 32]

3 < Max_th/Min_th < 5

In Equation 32, Max_th is the thickness of the thickest area of the lens, and Min_th is the thickness of the thinnest area of the lens. Max_th, the thickest thickness of the lens, may be the center thickness (CT) of the lens, and Min_th, the thinnest thickness of the lens, may be the edge thickness (ET) of the lens, but the opposite case is also possible. Max_th, the thickest thickness of the lens, may be the edge thickness (ET) of the lens, and Min_th, the thinnest thickness of the lens, may be the center thickness (CT) of the lens. Edge thickness (ET) refers to the thickness at the end of the effective diameter. If Equation 32 is satisfied, the optical system can control the effect on the effective focal length. Preferably, the condition of 3.5 < MAX_th/MIN_th ≤ 4 may be satisfied.

Here, the ratio between the maximum thickness and minimum thickness of the plastic lens may satisfy the following conditions. Max_PL_th is the thickness value of the thickest area of the plastic lens, and Min_PL_th is the thickness value of the thinnest area of the plastic lens. Max_PL_th may be the center thickness (CT) of the plastic lens, and Min_PL_th may be the edge thickness (ET) of the plastic lens. Edge thickness (ET) refers to the thickness at the end of the effective diameter. The opposite case is also possible. Max_PL_th may be the edge thickness (ET) of the plastic lens, and Min_PL_th may be the center thickness (CT) of the plastic lens. Edge thickness (ET) refers to the thickness at the end of the effective diameter.

Condition 1: 1 < Max_PL_th/Min_PL_th < 2.5

If it is smaller than the lower limit of condition 1, it is difficult to manufacture a plastic lens. In other words, it is manufactured by injecting high-temperature resin and curing it at low temperature. If the difference in thickness is large, the shrinkage may not be uniform as the lens cools at low temperature, resulting in a high surface defect rate. Additionally, if the range is larger than Condition 1, the plastic lens shrinks and expands as the temperature changes from -40 degrees to 105 degrees, and in this process, the rate of change in the shape of the lens increases significantly, which may deteriorate the performance of the optical system.

Preferably, the conditions of 1.0 < Max_PL_th/Min_PL_th < 1.8 and 1.0 < Max_PL_th/Min_PL_th < 1.5 may be satisfied.

[Equation 33]

0 < EPD / |L1R1| < 1

In Equation 33, EPD means the size (mm) of the entrance pupil of the optical system 1000, and L1R1 means the radius of curvature of the first surface (S1) of the first lens 101. When the optical system 1000 according to the embodiment satisfies Equation 33, the optical system 1000 can control incident light. Preferably, 0.3 < EPD / |L1R1| The condition of ≤ 0.5 can be satisfied.

[Equation 34]

Po4 * Po5 < 0

In Equation 34, Po4 is the refractive power value of the fourth lens 104, and Po5 is the refractive power value of the fifth lens 105. That is, the refractive power of the fourth and fifth lenses 104 and 105 are opposite to each other, so aberration can be improved and light can be effectively guided to the plastic lens. In the case of Po4 * Po5 > 0, the effect of improving chromatic aberration is not significant.

[Equation 35]

30 < V4-V5 < 50

In Equation 35, v4 is the Abbe number of the fourth lens 104, and V5 is the Abbe number of the fifth lens 105. If Equation 35 is satisfied, the difference in Abbe number between two adjacent lenses can be maintained above a certain value, and chromatic aberration can be improved. Equation 35 may preferably satisfy 20 ≤ v5-v4 ≤ 28. If it is less than the lower limit of Equation 35, there may be little improvement in the aberration characteristics of the optical system. Accordingly, if the difference in Abbe number between the object-side lens and the sensor-side lens in two adjacent lenses is 30 or more and 35 or less, aberration characteristics can be improved.

[Equation 36]

0 < |F1| / F < 10

In Equation 36, F is the effective focal length of the optical system, and F1 is the focal length of the first lens 101. If Equation 36 is satisfied, the TTL applied to the vehicle optical system can be set. Equation 36 preferably states that 5 < |F1| / F < 10 can be satisfied.

[Equation 37]

F_LG1/F_LG2 < 0

In Equation 37, F_LG1 is the focal length of the first lens group (LG1), and F_LG2 is the focal length of the second lens group (F_LG2). The focal length of the first lens group may have a negative value, and the focal distance of the second lens group may have a positive value. When Equation 37 is satisfied, the optical system 1000 can improve aberration characteristics such as chromatic aberration and distortion aberration. Equation 37 preferably has 5 < |F_LG1/F_LG2| < 10 can be satisfied.

[Equation 38]

1 < nPL /nGL < 2

In Equation 38, nGL represents the number of glass lenses, and nPL represents the number of plastic lenses. In Equation 38, by arranging the number of glass lenses to be more than 1 and less than 2 times the number of plastic lenses, the thickness of the optical system can be reduced and more diverse refractive power can be provided through the aspherical surface. Equation 38 may preferably satisfy 1 < nPL /nGL < 1.5.

[Equation 39]

CA_L7 < CA_L3 < CA_L1

In Equation 39, CA_L1 is the average effective diameter of the object side and the sensor side of the first lens 101, CA_L3 is the average effective diameter of the object side and the sensor side of the third lens 103, and CA_L7 is the average effective diameter of the seventh lens 107. This is the average effective diameter of the object side and the sensor side. If Equation 39 is satisfied, the first and second lens groups can be set, and the aberration can be improved through the first lens of the second lens group (LG2). CA_L3 can have the maximum effective diameter in the optical system.

[Equation 40]

1 < ΣPL_CT / ΣGL_CT < 2

In Equation 40, ΣPL_CT is the sum of the center thicknesses of the plastic lens(s), and ΣGL_CT is the sum of the center thicknesses of the glass lenses. If Equation 40 is satisfied, the entire TTL can be controlled by setting the relationship between the thickness of the plastic lens and the thickness of the glass lens compared to TTL. Equation 40 may preferably satisfy 1 <ΣPL_CT/ΣGL_CT< 1.5.

[Equation 41]

1 < ΣPL_Index / ΣGL_Index < 2

In Equation 41, ΣPL_Index is the sum of the refractive index thicknesses in the d-line of the plastic lens(s), and ΣGL_Index is the sum of the refractive indices in the d-line of the glass lenses. If Equation 41 is satisfied, the overall resolution can be controlled by setting the refractive index relationship between the plastic lens and the glass lens. Equation 41 may preferably satisfy 1 < ΣPL_Index / ΣGL_Index < 1.5.

[Equation 42]

10 < TTL < 45

In Equation 42, total track length (TTL) means the distance (mm) from the center of the first surface (S1) of the first lens 101 to the upper surface of the image sensor 300 on the optical axis (OA). By setting the TTL to exceed 10 or 20 in Equation 42, an optical system for a vehicle can be provided. Equation 42 may preferably satisfy the condition of 30 < TTL ≤ 40 or TD < TTL.

[Equation 43]

2 < ImgH < 10

Equation 43 can set the diagonal size (2*ImgH) of the image sensor 300 and provide an optical system having a sensor size for a vehicle. Equation 43 preferably satisfies 4 ≤ ImgH < 6.

[Equation 44]

1 < BFL < 3.5

In Equation 44, BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens. If Equation 44 is satisfied, the installation space for the filter 500 and the cover glass 400 can be secured, the assembling of the components is improved through the gap between the image sensor 300 and the last lens, and the coupling reliability is improved. can do. Equation 44 may preferably satisfy 2 ≤ BFL ≤ 3. If the BFL is less than the range of Equation 44, some of the light traveling to the image sensor may not be transmitted to the image sensor, which may cause resolution deterioration. If the BFL exceeds the range of Equation 44, stray light may enter and the aberration characteristics of the optical system may deteriorate.

[Equation 45]

3 < F < 40

Equation 45 can set the overall focal length (F) to suit the vehicle optical system. Equation 45 can satisfy 5 < F < 20.

[Equation 46]

FOV < 45

In Equation 46, FOV (Field of view) refers to the angle of view (Degree) of the optical system 1000, and can provide a vehicle optical system with an angle of less than 45 degrees. FOV may preferably satisfy 20 ≤ FOV ≤ 40.

[Equation 47]

1 < TTL / CA_max < 5

In Equation 47, CA_max refers to the largest effective diameter (mm) among the object side and sensor side of the plurality of lenses, and TTL (Total track length) refers to the image sensor 300 from the vertex of the first surface (S1) of the first lens. ) means the distance (mm) from the optical axis (OA) to the upper surface of Equation 47 establishes the relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby providing an improved optical system for vehicles. Equation 47 may preferably satisfy 1.5 < TTL / CA_max ≤ 3.

[Equation 48]

2 <TTL/ImgH<10

In Equation 48, TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor 300, and ImgH is the optical axis. means the distance from the diagonal end of the image sensor or 1/2 of the maximum diagonal length. If Equation 48 is satisfied, the optical system 1000 can have a TTL for application to the automotive image sensor 300, thereby providing improved image quality. Equation 48 may preferably satisfy 4 < TTL / ImgH < 10.

[Equation 49]

0.1 <BFL/ImgH<1

In Equation 49, BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens, and ImgH is the distance from the optical axis to the diagonal end of the image sensor or 1/2 of the maximum diagonal length. If Equation 49 is satisfied, the optical system 1000 can secure the back focal length (BFL) to apply the size of the vehicle image sensor 300, and set the gap between the last lens and the image sensor 300. and can have good optical characteristics in the center and periphery of the field of view (FOV). Equation 49 may preferably satisfy 0.2 < BFL / ImgH < 0.8.

[Equation 50]

5 <TTL/BFL<20

In Equation 50, TTL (Total Track Length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor 300, and BFL means the distance (mm) from the image sensor 300. It means the optical axis distance from the sensor 300 to the center of the sensor side of the last lens. If Equation 50 is satisfied, the optical system 1000 can secure BFL. Equation 50 may preferably satisfy 10 < TTL / BFL < 15.

[Equation 51]

1 < TTL/F < 3

In Equation 51, TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor 300, and F is the optical system is the effective focal length of Accordingly, an optical system for a driver assistance system can be provided. Equation 51 may preferably satisfy 2 ≤ TTL/F ≤ 3. If the optical system 1000 according to the embodiment satisfies Equation 51, the optical system 1000 can have an appropriate focal distance in the set TTL range, maintain the appropriate focal distance even when the temperature changes from low to high temperature, and form an image. Provides an optical system that can If it is less than the lower limit of Equation 51, it is necessary to increase the refractive power of the lenses, making correction of spherical aberration or distortion aberration difficult, and if it is more than the upper limit of Equation 51, the effective diameter or TTL of the lenses becomes longer, making it difficult to capture images. A problem may arise where the lens system becomes larger.

[Equation 52]

3 < F/BFL < 10

In Equation 52, F is the effective focal length of the optical system, and BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens. If Equation 52 is satisfied, the optical system 1000 can have a set angle of view and an appropriate focal distance, and can provide an optical system for a vehicle. Additionally, the optical system 1000 can minimize the gap between the last lens and the image sensor 300 and thus have good optical characteristics at the periphery of the field of view (FOV). Equation 52 preferably satisfies 3 < F / BFL < 6.

[Equation 53]

1 < F/ImgH < 5

In Equation 53, F is the effective focal length of the optical system, and ImgH means the distance from the optical axis to the diagonal end of the image sensor or 1/2 of the maximum diagonal length. This optical system 1000 may have improved aberration characteristics in the size of the vehicle image sensor 300. Equation 53 preferably satisfies 2 < F / ImgH < 4.

[Equation 54]

1 < F/EPD < 5

In Equation 54, F is the effective focal length of the optical system, and EPD is the entrance pupil size. Accordingly, the overall brightness of the optical system can be controlled. Equation 54 can preferably set 1 < F / EPD < 2.

[Equation 55]

0 < BFL/TD < 0.3

In Equation 55, TD is the optical axis distance of the lenses of the optical system 1000, and BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens. Accordingly, the overall size can be controlled while maintaining the resolution of the optical system. Equation 55 may preferably satisfy 0 < BFL/TD < 0.1. If the condition value of BFL/TD is more than 0.1, BFL is designed to be larger than TD, so the size of the entire optical system becomes large, making it difficult to miniaturize the optical system, and the distance between the seventh lens 107 and the image sensor is long. As a result, the amount of unnecessary light may increase between the seventh lens 107 and the image sensor, which causes a problem of lowering resolution, such as deterioration of aberration characteristics.

[Equation 56]

0 < EPD/Imgh/FOV < 0.2

Equation 56 can establish the relationship between the entrance pupil size (EPD), the length of half the maximum diagonal length of the image sensor (Imgh), and the angle of view. Accordingly, the overall size and brightness of the optical system can be controlled. Equation 56 may preferably satisfy 0 < EPD/Imgh/FOV < 0.1.

[Equation 57]

5 < FOV / F# < 30

Equation 57 can establish the relationship between the angle of view of the optical system and the F number (F#). Equation 57 preferably satisfies 10 < FOV / F # < 25. Here, F# can be set to 1.6 or less to provide a bright image.

[Equation 58]

30 < |F2/F5| < 50

In Equation 58, F2 is the focal length of the second lens 102, and F5 is the focal length of the fifth lens 105. In Equation 58, the relationship between the focal lengths of the second lens 102 and the fifth lens 105 can be established. Within the optical system 1000, the absolute value of the focal length of the second lens 102, which is made of glass, is the largest, and the absolute value of the focal distance of the fifth lens 105, which is made of plastic, is the smallest, thereby increasing the incident efficiency. It can be guided to the image sensor 300 by increasing and adjusting the refractive power between the lenses made of glass and plastic. Equation 58 preferably has 30 < |F2/F5| < 40 can be satisfied.

[Equation 59]

0.05 < |Sag_i / (CA_i/2)| < 0.2 (i=S1,S2,S3,S4)

Equation 59 can set the relationship between the Sag value and the effective diameter (CA) of the first to fourth surfaces (S1, S2, S3, and S4) of the first and second lenses (101, 102), and if this is satisfied, the refractive power of the lenses can improve. Here, Equation 59 states that if the condition of n1 > 1.7 is further satisfied, the first and second lenses 101 and 102 emit light with sufficient power even without drastically designing the radius of curvature of the first and second lenses 101 and 102 within the effective diameter. It is possible to collect them.

[Equation 60]

0 < |L4R2-L5R1| < 5

Equation 60 can set the relationship between the radius of curvature of the eighth surface (S8) on the sensor side of the fourth lens 104 and the radius of curvature of the ninth surface (S9) on the object side of the fifth lens 105, which is If satisfactory, the curvature radii of the fourth lens 104 and the fifth lens 105 made of plastic are similar within the effective diameter area, so the change in focal length and optical performance due to temperature change can be offset.

[Equation 61]

0 < |L5R2-L6R1| < 5

Equation 61 can set the relationship between the radius of curvature of the 10th surface (S10) on the sensor side of the 5th lens 105 and the radius of curvature of the 9th surface (S11) on the object side of the 6th lens 106, which is If satisfactory, the curvature radii of the fifth lens 105 and the sixth lens 106 made of plastic are similar within the effective diameter area, so the change in focal length and optical performance due to temperature change can be offset.

[Equation 62]

In Equation 62, Z is Sag and can mean the distance in the optical axis direction from any position on the aspherical surface to the vertex of the aspherical surface. Y may mean the distance from any location on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. 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 or two of Equations 1 to 62. In this case, the optical system 1000 may have improved optical characteristics. In detail, when the optical system 1000 satisfies at least one or two of Equations 1 to 62, the optical system 1000 has improved resolution and can improve aberration and distortion characteristics. In addition, the optical system 1000 can secure a back focal length (BFL) for applying the automotive image sensor 300, compensate for the decrease in optical characteristics due to temperature changes, and the last lens and image sensor 300. The gap between them can be minimized, allowing good optical performance in the center and periphery of the field of view (FOV).

Table 2 shows the items of the above-described equations in the optical system 1000 of the embodiment, including TTL (Total track length) (mm), BFL (Back focal length), and effective focal length (F) (mm) of the optical system 1000. ), 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), the first Focal distance of each of the to seventh lenses (F1, F2, F3, F4, F5, F6, F7) (mm), sum of refractive index, sum of Abbe number, sum of thickness (mm), sum of spacing between adjacent lenses, effective diameter Characteristics, the sum of the refractive index of the glass lens, the sum of the refractive index of the plastic material, angle of view (FOV) (Degree), edge thickness (ET), focal length of the first and second lens groups, F number, etc.

item value item value F 15.1 ET1 2.0891 F1 -147.0400 ET2 7.1721 F2 -620.6040 ET3 1.9951 F3 21.4640 ET4 2.2733 F4 129.7620 ET5 5.1141 F5 -16.1812 ET6 2.9168 F6 12.3782 ET7 3.4161 F7 -26.3173 F-number 1.600 F_LG1 -130.841 FOV 34.3447 F_LG2 15.17991 E.P.D. 9.4375 ΣIndex 11.5109 BFL 2.8222 ΣAbbe 276.2826 TD 36.2804 ΣCT 27.0905 ImgH 4.6300 ΣCG 9.1899 SD 22.1578 CA_max 14.902 TTL 39.1026 CA_min 8.631 GLca_Aver 12.4014 CA_Aver 11.202 PLca_Aver 10.3019 CT_max 6.9958 image sensor 3840*2160 CT_min 2.000 CT_Aver 3.8700

Table 3 shows the result values for Equations 1 to 61 described above in the optical system 1000 of the embodiment. Referring to Table 3, it can be seen that the optical system 1000 satisfies at least one, two, or three of Equations 1 to 61. In detail, it can be seen that the optical system 1000 according to the embodiment satisfies all of Equations 1 to 61. 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 value One 0.5 < CT1 / ET1 < 1 0.9573 2 0.1 < CT1/CA_L1S1 < 0.3 0.1342 3 Po1 < 0 -0.01 4 1.7 < n1 < 2.2 1.7766 5 27 <FOV_H<33 29.99 6 L3R1>0, L3S2<0 Satisfaction 7 1 < L7S2_max_sag to Sensor < 3 2.5999 8 0 < CT1 / CT7 < 1 0.7767 9 0 < CA_L1S1 / CA_L4S1 < 2 1.3194 10 0 < CA_L7S2 / CA_L5S2 < 2 0.9703 11 0 < CA_L1S2 / CA_L2S1 < 2 1.1430 12 0.5 < CA_L4S1 / CA_L5S2 < 2 1.1619 13 2 < L3R1/(CA_L3S1/2) < 5 3.3650 14 1 < CA_GL_AVER/CA_PL_AVER < 1.5 1.2037 15 1.2 < GL_CA1_AVER/PL_CA1_AVER < 1.5 1.2015 16 CG3 < CG5 < CG1 Satisfaction 17 1 < CT7 / CG6 < 3 1.5262 18 3 < CT2/CT1 < 5 3.4979 19 10 < L7R1 / CT7 < 20 11.2736 20 1 < CT_Max / CG_Max < 2 1.3916 21 2 < ΣCT / ΣCG < 3 2.9478 22 10 < ΣIndex <20 11.5109 23 10 < ΣAbb / ΣIndex <35 24.0018 24 1 < ΣCT / ΣET < 2 1.0846 25 0.5 < CA_L3S1 / CA_min < 2 1.2821 26 1 < CA_max / CA_min < 3 1.7266 27 1 < CA_max / CA_Aver < 3 1.3303 28 0.5 < CA_min / CA_Aver < 2 0.7705 29 1 < CA_max / (2*ImgH) < 3 1.6093 30 1 < TD / CA_max < 4 2.4345 31 0 < F / L1R1 < 1 0.5368 32 3 < Max_th/Min_th < 5 3.5947 33 0 < EPD / |L1R1| < 1 0.3355 34 Po4 * Po5 < 0 Satisfaction 35 30 < V4-V5 < 50 34.4943 36 0 < | F1| / F < 10 9.7377 37 F_LG1/F_LG2 < 0 -8.6193 38 1 < nPL /nGL < 2 1.333 39 CA_L7 < CA_L3 < CA_L1 Satisfaction 40 1 < ΣPL_CT / ΣGL_CT < 2 1.2115 41 1 < ΣPL_Index / ΣGL_Index < 2 1.2531 42 10 < TTL < 45 39.1026 43 2 < ImgH < 10 4.630 44 1<BFL<3.5 2.8222 45 3 < F < 40 15.100 46 FOV < 45 34.3447 47 1 < TTL / CA_max < 5 2.6238 48 2 <TTL/ImgH<10 8.4454 49 0.1 <BFL/ImgH<1 0.6095 50 5 <TTL/BFL<20 13.8556 51 1 < TTL/F < 3 2.5895 52 3 < F/BFL < 10 5.3505 53 1 < F/ImgH < 5 3.2613 54 1 < F/EPD < 5 1.600 55 0 < BFL/TD < 0.3 0.0777 56 0 < EPD/Imgh/FOV < 0.2 0.0593 57 5 < FOV / F# < 30 21.4654 58 30 < |F2/F5| < 50 38.3533 59 0.05<|Sag_i / (CA_i / 2)| < 0.2 (i=S1,S2,S3,S4) Satisfaction 60 0 < |L4R2-L5R1| < 5 3.497 61 0 < |L5R2-L6R1| < 5 0.7422

The optical system according to the second embodiment of the present invention will be described.

FIG. 15 is a side cross-sectional view of an optical system and a camera module having the same according to a second embodiment, FIG. 16 is a side cross-sectional view for explaining the relationship between the nth and n-1th lenses according to FIG. 15, and FIG. 17 is a side cross-sectional view of FIG. 15. This is a table showing the lens characteristics of the optical system of , and Figure 18 is a table showing the aspheric coefficients of the lenses in the optical system of Figure 15, and Figure 19 is a table showing the thickness of each lens and the gap between adjacent lenses in the optical system of Figure 15. 20 is a table showing the Sag values of the lens surfaces of the third to sixth lenses in the optical system of FIG. 15, and FIG. 21 is a table showing the CRA (Chief Ray Angle) at room temperature, low temperature, and high temperature according to the position of the image sensor in the optical system of FIG. 15. ) is a table showing data, and FIGS. 22 to 24 are graphs showing data on the diffraction MTF (Modulation Transfer Function) at room temperature, low temperature, and high temperature of the optical system of FIG. 15, and FIGS. 25 to 27 are graphs of the optical system of FIG. 15. This is a graph showing data on aberration characteristics at room temperature, low temperature, and high temperature, and Figure 28 is a graph showing relative illuminance according to the height of the image sensor according to the embodiment.

15 to 18, the optical system 2000 includes a lens unit 200, and the lens unit 200 may include first to seventh lenses 201 to 207. The first to seventh lenses 201 to 207 may be sequentially arranged along the optical axis OA of the optical system 2000. Light corresponding to object information may pass through the first to seventh lenses 201 to 207 and the filter 500 and enter the image sensor 300.

The first lens 201 is the lens closest to the object in the first lens group LG1. The seventh lens 207 is the closest lens to the image sensor 207 in the second lens group LG2 or the lens unit 200. The first and second lenses 201 and 202 may be the first lens group (LG1), and the third to seventh lenses (203, 204, 205, 206, 207) may be the second lens group (LG2). The aperture may be disposed either around the object side or sensor side of the first lens 201, or around the object side or sensor side of the second lens 202. For example, the aperture (Stop) may be placed around the sensor side of the second lens 202.

The first lens 201 may be placed closest to the object. The first lens 201 may be placed furthest from the sensor side. The first lens 201 may have positive (+) refractive power at the optical axis (OA). The first lens 201 may include a plastic material or a glass material, for example, a glass material. The first lens 201 made of glass can reduce changes in the center position and radius of curvature due to temperature changes depending on the surrounding environment, and can protect the entrance side of the optical system 2000.

Based on the optical axis, the object-side first surface S1 of the first lens 201 may be convex, and the sensor-side second surface S2 may be concave. The first lens 201 may have a meniscus shape that is convex toward the object. The first lens 201 is made of glass and may have a spherical surface.

The effective radius r11 of the first lens 201 may be larger than the effective radius of the plastic lenses. Alternatively, at least one of the object side and the sensor side of the first lens 201 may have a free curved surface, that is, a non-rotationally symmetric curved surface.

Since the first surface (S1) is concave and the second surface (S2) is convex, incident light can be refracted in a direction away from the optical axis (OA), and the gap between the first and second lenses (201 and 202) can be reduced. I can give it. Additionally, depending on the shape of the lens surface of the first lens 201, the effective diameter of the sensor side of the second lens 202 can be designed to be smaller than the effective diameter of the object side. The first surface S1 of the first lens 201 may be provided without a critical point from the optical axis OA to the end of the effective area, that is, the edge. The second surface S2 of the first lens 201 may be provided without a critical point.

The refractive index (n1) of the first lens 201 may satisfy the condition of n1>1.8 or n1>1.82. Since the refractive index (n1) of the first lens 201 is the largest in the lens unit 200, the radii of curvature of the first and second lenses 201 and 202 can be increased, and lens manufacturing can be easy. If the refractive index (n1) of the first lens 201 is smaller than the condition, the lens surface must be sharply concave or convex to increase the refractive power of the first and second lenses 201 and 202, and in this case, lens manufacturing is required. It is not easy, and the rate of lens defects increases and may cause a decrease in yield.

The second lens 202 may be disposed second on the object side. The second lens 202 may be placed sixth on the sensor side. The second lens 202 may be disposed between the first lens 201 and the third lens 203. The second lens 202 may have negative refractive power at the optical axis (OA). The second lens 202 may include plastic or glass. For example, the second lens 202 may be made of glass.

Based on the optical axis OA, the object-side third surface S3 of the second lens 202 may be concave, and the sensor-side fourth surface S4 may be convex. The second lens 202 may have a meniscus shape that is convex toward the sensor. The second lens 202 is made of glass and may be spherical.

The aperture stop may be disposed around the fourth surface S4 on the sensor side of the second lens 202. Aperture can reduce TTL within the range of view angle, and miniaturization of the optical system is possible. Accordingly, it is possible to prevent a decrease in the yield by weight of the optical system and improve production efficiency. Additionally, the optical system can be miniaturized by reducing the TTL at a horizontal angle of view (FOV_H) of 25 to 36 degrees.

The third lens 203 may be arranged third from the object side. The third lens 203 may be placed fifth on the sensor side. The third lens 203 may be disposed between the second lens 202 and the fourth lens 204. The third lens 203 may have positive (+) refractive power at the optical axis (OA). The third lens 203 may include plastic or glass. For example, the third lens 203 may be made of glass.

Based on the optical axis, the object-side fifth surface S5 of the third lens 203 may be convex, and the sensor-side sixth surface S6 may be convex. The third lens 203 may have a shape in which both sides are convex at the optical axis (OA). The third lens 203 is made of glass and may be spherical. At least one or both of the fifth surface S5 and the sixth surface S6 may be spherical. At least one or both of the fifth surface S5 and the sixth surface S6 may be provided without a critical point from the optical axis OA to the end of the effective area. Since both sides of the third lens 203 are convex, the TTL and number of lenses of the optical system can be minimized and light can be effectively refracted.

The fourth lens 204 may be placed fourth on the object side. The fourth lens 204 may be placed fourth on the sensor side. The fourth lens 204 may be disposed between the third lens 203 and the fifth lens 205. The fourth lens 204 may have positive (+) or negative (-) refractive power at the optical axis (OA). The fourth lens 204 may have positive (+) refractive power. The fourth lens 204 may have a positive (+) refractive power that is different from that of the fifth lens 205. The fourth lens 204 may include plastic or glass. For example, the fourth lens 204 may be made of plastic. The fourth lens 204 may be made of the same material as the fifth lens 205.

Based on the optical axis, the object-side seventh surface S7 of the fourth lens 204 may be convex, and the sensor-side eighth surface S8 may be concave. The fourth lens 204 may have a meniscus shape that is convex toward the object. The fourth lens 204 is made of plastic and may have an aspherical surface. At least one or both of the seventh surface S7 and the eighth surface S8 may be aspherical. The aspheric coefficients of the seventh and eighth surfaces (S7 and S8) can be provided as S1 and S2 of L4 in FIG. 4. The seventh surface S7 and the eighth surface S8 may be provided without a critical point from the optical axis OA to the end of the effective area.

The fifth lens 205 may be placed fifth on the object side. The fifth lens 205 may be placed third on the sensor side. The fifth lens 205 may be disposed between the fourth lens 204 and the sixth lens 206. The fifth lens 205 may have positive (+) or negative (-) refractive power at the optical axis (OA). The fifth lens 205 may have negative refractive power. The fifth lens 205 may have a negative (-) refractive power that is different from the refractive power of the fourth lens 204. The fifth lens 205 may include plastic or glass. For example, the fifth lens 205 may be made of plastic. The fifth lens 205 may be made of the same material as the fourth lens 204.

Based on the optical axis OA, the object-side ninth surface S9 of the fifth lens 205 may be convex, and the sensor-side tenth surface S10 may be concave. The fifth lens 205 may have a meniscus shape that is convex from the optical axis OA toward the object. The fifth lens 205 is made of plastic and may have an aspherical surface. At least one or both of the ninth surface S9 and the tenth surface S10 may be aspherical. The aspherical coefficients of the 9th and 10th surfaces (S9 and S10) can be provided as S1 and S2 of L5 in FIG. 4. The ninth surface S9 and the tenth surface S10 may be provided without a critical point from the optical axis OA to the end of the effective area.

The center spacing (CG4) of the fourth lens 204 and the fifth lens 205 may satisfy 0.05 mm to 0.3 mm, for example, 0.08 mm to 0.25 mm. In addition, the difference between the radius of curvature of the eighth surface S8 on the sensor side of the fourth lens 204 and the ninth surface on the object side of the fifth lens 205 may satisfy 2 mm to 5 mm, for example. 2.5 mm to 3.5 mm can be satisfied. Through the above conditions, the curvature radii of the sensor-side eighth surface S8 of the fourth lens 204 and the object-side ninth surface S9 of the fifth lens 205 are set to be similar, so that the curvature radius of the bonded lens within the effective diameter area is set to be similar. May have optical properties.

More specifically, the product of the refractive power of the fourth lens 204 adjacent to the object side and the refractive power of the fifth lens 205 adjacent to the sensor side may be less than 0. The product of the focal length of the fourth lens 204 adjacent to the object side and the focal length of the fifth lens 205 adjacent to the sensor side may be less than 0. Accordingly, the aberration characteristics of the optical system can be improved. If the refractive powers of the two lenses of the bonded lens 145 are the same, there is a limit to improving the aberration.

The fourth lens 204 and the fifth lens 205 are made of plastic materials with different refractive indexes, and any two consecutive lenses among the third to sixth lenses located in the middle or behind the middle within the lens unit 200 Since it is placed in , chromatic aberration correction can be more efficient.

The sixth lens 206 may be placed sixth on the object side. The sixth lens 206 may be placed second on the sensor side. The sixth lens 206 may be disposed between the fifth lens 205 and the seventh lens 207. The sixth lens 206 may have positive (+) or negative (-) refractive power at the optical axis (OA). The sixth lens 206 may have positive (+) refractive power. The sixth lens 206 may include plastic or glass. For example, the sixth lens 206 may be made of plastic.

Based on the optical axis OA, the object-side 11th surface S11 of the sixth lens 206 may be convex, and the sensor-side 12th surface S12 may be concave. The sixth lens 206 may have a meniscus shape that is convex from the optical axis OA toward the object. At least one or both of the 11th surface (S11) and the 12th surface (S12) may be aspherical. The aspherical coefficients of the 11th and 12th surfaces (S11 and S12) can be provided as L1 and L2 of L6 in FIG. 18.

The 11th surface S11 of the sixth lens 206 may be provided without a critical point from the optical axis OA to the end of the effective area. The twelfth surface S12 may be provided without at least one critical point from the optical axis OA to the end of the effective area.

The seventh lens 207 may be placed closest to the sensor side. The seventh lens 207 may be placed furthest from the object. The seventh lens 207 may have positive (+) or negative (-) refractive power at the optical axis (OA). The seventh lens 207 may have negative refractive power. The seventh lens 207 may include plastic or glass. For example, the seventh lens 207 may be made of plastic.

On the optical axis, the object-side 13th surface S13 of the seventh lens 207 may be convex, and the sensor-side 14th surface S14 may be concave. The seventh lens 207 may have a meniscus shape convex toward the object. At least one of the 13th surface (S13) and the 14th surface (S14) may be an aspherical surface. For example, both the 13th surface S13 and the 14th surface S14 may be aspherical surfaces. The aspheric coefficients of the 13th and 14th surfaces (S13 and S14) can be provided as S1 and S2 of L7 in FIG. 18.

The 13th surface S13 of the seventh lens 207 may have a critical point from the optical axis OA to the end of the effective area. When the 13th surface S13 has a critical point, it may be located at more than 50% of the effective radius r71 from the optical axis OA, or may be located in the range of 52% to 70%, or 53% to 60%. When the 14th surface S14 has a critical point, it may be located at more than 70% of the effective radius r72 from the optical axis OA, or within a range of 70% to 90% or 75% to 85%.

The seventh lens 207 may be a plastic lens closest to the image sensor 300. Additionally, by arranging two or more plastic lenses adjacent to the image sensor 300, aberrations such as spherical aberration and chromatic aberration can be improved by the lens surface having an aspherical surface, and the influence on resolution can be controlled. Additionally, by placing a plastic lens as a lens adjacent to the image sensor 300, it can be insensitive to assembly tolerances compared to a lens made of glass. In other words, being insensitive to assembly tolerances means that optical performance may not be significantly affected even if the assembly is assembled with a slight difference compared to the design. In addition, by providing two lenses 206 and 207 adjacent to the image sensor 300 made of plastic, optical performance can be improved by the lens surface having an aspherical surface, for example, aberration characteristics can be improved and resolution can be prevented. .

The sixth lens 206 and the seventh lens 207 are arranged to be spaced apart, but may include features of a bonded lens. The sixth lens 206 and the seventh lens 207 may have opposite refractive powers. The product of the refractive power of the sixth lens 206 and the refractive power of the seventh lens 207 may be less than 0. The product of the focal length of the sixth lens 206 and the focal length of the seventh lens 207 may be less than 0. Accordingly, the aberration characteristics of the optical system can be improved. If the refractive powers of two lenses that have the characteristics of a bonded lens are the same, there is a limit to improving aberrations.

The sixth lens 206 and the seventh lens 207 are arranged to be spaced apart, but may include features of a bonded lens. The sixth lens 206 and the seventh lens 207 may have opposite refractive powers. The product of the refractive power of the sixth lens 206 and the refractive power of the seventh lens 207 may be less than 0. The product of the focal length of the sixth lens 206 and the focal length of the seventh lens 207 may be less than 0. Accordingly, the aberration characteristics of the optical system can be improved. If the refractive powers of two lenses that have the characteristics of a bonded lens are the same, there is a limit to improving aberrations.

At least one or both of the 13th surface S13 and the 14th surface S14 of the seventh lens 207 may have a critical point. The 13th surface S13 of the seventh lens 207 may have a first critical point P1 from the optical axis OA to the end of the effective area. The first critical point P1 of the 13th surface S13 may be located at 55% or more of the effective radius from the optical axis OA, or may be located at 55% to 75% of the effective radius, or 60% to 70% of the effective radius. The first critical point of the 13th surface S13 may be located at a distance of 1.5 mm or more from the optical axis OA, for example, in the range of 1.3 mm to 1.8 mm or 1.4 mm to 1.6 mm. As another example, the 13th side S13 may be provided without a critical point. The 13th surface (S13) having this first critical point (P1) can refract incident light to the center and periphery and improve aberration. The first and second critical points (P1, P2) are the optical axis (OA) and the sign of the slope value with respect to the direction perpendicular to the optical axis (OA) is changed from positive (+) to negative (-) or from negative (-) to positive (+). ), which may mean a point where the slope value is 0. Additionally, the first and second critical points (P1, P2) may be points where the slope value of the tangent line passing through the lens surface decreases as the value increases, or points where it decreases and then increases.

The 14th surface S14 of the seventh lens 207 may have at least one second critical point P2 from the optical axis OA to the end of the effective area. The second critical point (P2) of the 14th surface (S14) may be located at a distance of 60% or more of the effective radius (r72) from the optical axis (OA), or may be located in the range of 60% to 80% or 65% to 75% of the effective radius (r72). there is. The second critical point P2 of the 14th surface S14 may be located at a distance of 2.9 mm or more from the optical axis OA, for example, in the range of 2.9 mm to 3.9 mm or 3 mm to 3.7 mm. Accordingly, the second critical point P2 is disposed closer to the edge than the first critical point P1, so that the seventh lens 207 can refract the incident light to the periphery of the image sensor 300.

The average effective radius of the 13th and 14th surfaces (S13, S14) of the seventh lens 207 is arranged to be smaller than Imgh, which is 1/2 of the diagonal length of the image sensor 300, which has a second critical point (P2). Light can be refracted to the periphery of the image sensor 300 by the fourteenth surface S14.

15 and 16, the center thickness of the first to seventh lenses 201 to 207 is indicated by CT1 to CT7, and the edge thickness, which is the end of the effective area of each lens, is indicated by ET1 to ET7, and the thickness between the two adjacent lenses is indicated by CT1 to CT7. The center gap is indicated by CG1~CG6, and the edge gap between the edges of each lens is indicated by EG1~EG6.

Referring to FIG. 16, back focal length (BFL) is the optical axis distance from the image sensor 300 to the center of the last lens. In FIG. 15 , TTL is the optical axis distance from the center of the first surface S1 of the first lens 201 to the upper surface of the image sensor 300.

FIG. 17 is an example of lens data of the optical system of the embodiment of FIG. 15. As shown in Figure 17, the radius of curvature at the optical axis (OA) of the first to seventh lenses (201, 202, 203, 204, 205, 206, 207), the thickness of the lens, the center distance between the lenses, d-line You can set the size of the refractive index, Abbe's Number, and clear aperture (CA).

As shown in FIG. 18 , the lens surfaces of the fourth, fifth, sixth, and seventh lenses 204, 205, 206, and 207 among the lenses of the lens unit 200 in the embodiment may include an aspherical surface with a 30th order aspherical coefficient. For example, the fourth, fifth, sixth, and seventh lenses 204, 205, 206, and 207 may include lens surfaces having a 30th order aspherical coefficient. As described above, an aspheric surface with a 30th order aspheric coefficient (a value other than “0”) can particularly significantly change the shape of the aspherical surface in the peripheral area, so the optical performance of the peripheral area of the field of view (FOV) can be well corrected.

As shown in Figure 19, the thickness (T1-T7) of the first to seventh lenses (201, 202, 203, 204, 205, 206, 207) and the gap (G1-G6) between two adjacent lenses can be set. As shown in Figure 19, in the Y-axis direction, the thickness of each lens (T1-T7) can be expressed at intervals of 0.1 mm or 0.2 mm or more, and the interval between each lens (G1-G6) can be expressed at intervals of 0.1 mm or 0.2 mm or more. It can be displayed every time.

17 and 19, when comparing the absolute values of the radii of curvature of each lens, the radius of curvature of the sixth surface S6 of the third lens 203 at the optical axis OA is the largest among the lenses, and 5 The radius of curvature of the tenth surface (S10) of the lens 205 may be the smallest among the lenses. The difference between the maximum radius of curvature and the minimum radius of curvature may be in the range of 10 times or more, for example, 15 to 20 times.

When explaining the central thickness of a lens based on the optical axis, the central thickness (CT4) of the first lens 201 is the largest among the lenses, and the central thickness (CT1) of the first lens 201 is the smallest among the lenses. The difference between the maximum and minimum center thickness of the lens may be in the range of 3 mm or more and 5 mm or less.

Describing the center spacing (CG) between the lenses, the center spacing (CG6) between the sixth lens 206 and the seventh lens 207 is maximum, and between the second and third lenses 202 and 203, the third, The center spacing between the fourth lens 203 and 204 and the fourth and fifth lenses 204 and 205 may be minimal. The difference between the maximum center distance and the minimum center distance among the spaced lens distances may be 1.5 mm or more, for example, in the range of 1.5 mm to 2 mm. In addition, by providing the maximum center spacing between lenses to be less than 70% of the maximum center thickness, for example, in the range of 30% to 70%, the camera uses plastic lenses with a thin thickness without increasing the center spacing compared to the center thickness of each lens. The thickness of the module may not be increased.

When explaining the effective diameter, the lens with the maximum effective diameter may be any one of glass lenses, for example, the first lens 201 adjacent to the object. The lens having the maximum effective diameter may be the first lens 201. Here, the effective diameter is the average of the effective diameter of each lens on the object side and the effective diameter on the sensor side. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens 201 or the second surface (S2) of the first lens 201.

The lens having the minimum effective diameter may be any one of plastic lenses, for example, the seventh lens 207 adjacent to the image sensor 300. For example, the effective diameter of the seventh lens 207 may be the minimum within the lens unit 200. The lens surface having the minimum effective diameter may be the 13th surface (S13) of the 7th lens 207.

The effective diameter of each of the first to fourth lenses (201-204) adjacent to the object side may be larger than the effective diameter of the fifth, sixth, and seventh lenses (205, 206, and 207) adjacent to the sensor side. The effective diameters of the first to fourth lenses 201 - 204 may be larger than the diagonal length of the image sensor 300 . The average effective diameter of the seventh lens 207 may be smaller than the diagonal length of the image sensor 300. Accordingly, light incident through a plurality of lenses aligned along the optical axis can be guided to the image sensor 300.

Describing the refractive index, the refractive index of the first lens 201 is the highest among the lenses and may be greater than 1.8, for example, greater than 1.82. Either or both of the second lens 202 and the sixth lens 206 may have the lowest refractive index among the lenses. For example, it may be less than 1.6, such as less than 1.55. The difference between the maximum and minimum refractive indices may be 0.2 or more. By providing a high refractive index lens made of glass closest to the object, and providing a low refractive index lens made of plastic for the lens adjacent to the glass lens and the lens adjacent to the image sensor 300, incident efficiency is increased, and the lens adjacent to the glass material lens and the lens adjacent to the image sensor 300 are provided as low refractive index lenses made of plastic. It is possible to guide the image sensor 300 by adjusting the refractive power between the lenses.

Comparing the Abbe number, the Abbe number of the third lens 203 is the largest among the lenses and may be 60 or more. The Abbe number of the fifth lens 205 and the seventh lens 207 is the minimum among the lenses and may be 25 or less. The difference between the maximum refractive index and the minimum Abbe number may be 40 or more. By providing the largest Abbe number of the third lens 203 adjacent to the center of the optical system 1000 and the smallest Abbe number of the seventh lens 207 with a low refractive index adjacent to the image sensor 300, the glass material It is possible to adjust the color dispersion of light traveling between the lenses and guide it to the image sensor 300 by increasing the color dispersion between the lenses made of glass and plastic.

The focal lengths (F2, F5, and F7) of the second, fifth, and seventh lenses (201, 202, 205, and 207) may have a negative (-) sign. The second, fifth, and seventh lenses (201, 202, 205, and 207) may have negative refractive power. The focal lengths F1, F3, F4, and F6 of the first, third, fourth, and sixth lenses 201, 203, 204, and 206 may have a positive (+) sign. The first, third, fourth, and sixth lenses (201, 203, 204, and 206) may have positive (+) refractive power. Third and fourth lenses 203 and 204 with positive (+) refractive power may be disposed on the sensor side of the second lens 202 with negative (-) refractive power. Through this, the light incident from the object side can move away from the optical axis direction and then converge again in the optical axis direction, forming a stable optical path.

Additionally, the sixth lens 206 and seventh lens 207, which are adjacent lenses, can satisfy the following conditions.

Condition 1: Refractive index of a lens with positive refractive power < Refractive index of a lens with negative refractive power

Condition 2: Dispersion value of a lens with positive refractive power > Dispersion value of a lens with negative refractive power

Here, among the plastic lenses, the sixth lens 206 has positive refractive power and the seventh lens 207 has negative refractive power, so according to conditions 1 and 2, the refractive index of the sixth lens is greater than that of the seventh lens. It is smaller than the refractive index, and the dispersion value of the sixth lens is greater than the dispersion value of the seventh lens. Chromatic aberration occurring in plastic lenses can be corrected with plastic lenses. In addition, the 6th lens 206 and the 7th lens 207, which are plastic lenses arranged in succession, satisfy the refractive index difference of 0.1 to 0.15 and the Abbe number difference of 20 to 60, thereby reducing chromatic aberration occurring in the plastic lens. It can be compensated with

Optical systems produce chromatic aberration, and chromatic aberration is corrected using a bonded lens or two lenses placed in series. As the temperature changes from low to high, the lens repeats contraction and expansion. Since lenses made of the same material have the same amount of change in lens characteristics due to temperature changes, it is effective to correct chromatic aberration between lenses made of the same material even if the temperature changes. Therefore, in an embodiment of the present invention, the fourth lens 204, the fifth lens 205, the sixth lens 206, and the seventh lens 207 are used to correct chromatic aberration occurring in the plastic lens.

Additionally, by disposing glass lenses with relatively high Abbe numbers on the object side of the plastic lenses, chromatic dispersion can be reduced by the glass lenses and chromatic dispersion can be increased by the plastic lenses.

Comparing the focal lengths as absolute values, the focal length of the second lens 202 is the largest among the lenses and may be 55 or more or 200 or more. Among the lenses, the second lens 202 made of glass may have the largest focal length and the smallest refractive power. Among the lenses, the lens with the next largest focal length after the second lens 202 may be the first lens 201 made of glass. The focal length of the sixth lens 206 is the smallest among the lenses and may be 15 or less or 10 or less. Among the lenses, the sixth lens 206, which is made of plastic, may have the smallest focal length and the highest refractive power.

Accordingly, it is possible to have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the field of view range set in the optical system, and good optical performance in the periphery of the field of view.

There is a critical point on the sensor side of the seventh lens (207). The critical point is the point at which the trend of the sag value changes. In other words, it is the point where the sag value increases and then decreases, or the point where the sag value decreases and then increases. Referring to FIG. 20, it can be seen that the object side of the seventh lens 207 has a critical point between a point 1.5 mm apart and a point 2.0 mm apart in the direction perpendicular to the optical axis. The sag value of the object side of the 7th lens (207) increases to a point 1.6 mm apart in the direction perpendicular to the optical axis, and then decreases as it goes from a point 1.6 mm apart to a point 4.2 mm apart in the direction perpendicular to the optical axis. I'm doing it.

It can be seen that the sensor side of the seventh lens 207 has a critical point between a point 2.8 mm apart and a point 3.2 mm apart in the direction perpendicular to the optical axis. On the sensor side of the seventh lens (207), the sag value increases to a point 3 mm apart in the direction perpendicular to the optical axis, and then decreases as it goes from a point 3 mm apart to a point 4.7 mm apart in the direction perpendicular to the optical axis. . If a critical point exists on the sensor side of the seventh lens 207, that is, the sensor side of the last lens, that is, the lens side closest to the sensor, the TTL can be reduced, making it easy to miniaturize and lighten the optical system.

The thickness T1 of the first lens 201 may have a difference between the maximum thickness and the minimum thickness of 1 times or more, for example, 1 to 1.2 times, the center thickness (CT1) is the minimum, and the edge thickness (ET1) is the minimum. It can be maximum. The thickness T2 of the second lens 202 may have a maximum thickness ranging from 1 to 1.2 times the minimum thickness. The second lens 202 may have a minimum center thickness (CT2) and a maximum edge thickness (ET2). The thickness T3 of the third lens 203 may be maximum at the center and minimum at the edges, with the maximum thickness being in the range of 1.5 to 2 times the minimum thickness. The thickness T4 of the fourth lens 204 may be maximum at the center and minimum at the edge, with the maximum thickness ranging from 1 to 1.5 times the minimum thickness. The thickness T5 of the fifth lens 205 may be minimum at the center and maximum at the edge, with the maximum thickness being in the range of 1.1 to 1.5 times the minimum thickness. The thickness T6 of the sixth lens 206 may be maximum at the center and minimum at the edge, with the maximum thickness ranging from 1.1 to 1.5 times the minimum thickness. The thickness T7 of the seventh lens 207 may be minimum at the center and maximum at the edge, with the maximum thickness ranging from 1 to 1.5 times the minimum thickness.

Among the intervals G1-G6 between the lenses, the first interval G1 between the first and second lenses 201 and 202 may be maximum at the center and minimum at the edges. The second gap G2 between the second and third lenses 202 and 203 may be maximum at the edge and minimum at the center. The third gap G3 between the third and fourth lenses 203 and 204 may be maximum at the edge and minimum at the center. The fifth gap G5 between the fifth and sixth lenses 205 and 206 may be maximum at the center and minimum at the edges. The sixth gap G6 between the sixth and seventh lenses 206 and 207 may be maximum at the center and minimum at the edges.

As shown in FIG. 21, the chief ray angle (CRA) in the optical system and camera module of FIG. 15 is 10 degrees or more in the 1-field, which is the end of the diagonal length of the image sensor, for example, in the range of 10 to 35 degrees or 10 degrees. It may range from degrees to 25 degrees. Additionally, the angle difference of the main ray from low temperature (-40 degrees) to high temperature (95 degrees) may be less than 1 degree. Accordingly, even if the temperature changes from low to high, the difference in the angle of the main ray is not large and stable optical performance can be achieved.

28 is a graph showing the peripheral light ratio or relative illumination according to the image height in the optical system according to the embodiment, where the peripheral light ratio is 70% or more, for example, 75% or more from the center of the image sensor to the end of the diagonal. You can see that it appears. In other words, it can be seen that there is almost no difference in ambient illuminance (Zoom positions 1, 2, 3) depending on room temperature, low temperature, and high temperature up to 4.5 mm or more from the optical axis.

Figures 22 to 24 are graphs showing diffraction MTF (modulation transfer function) at room temperature, low temperature, and high temperature in the optical system of Figure 15, and are graphs showing luminance ratio (modulation) according to spatial frequency. . 22 to 24, in an embodiment of the invention, the deviation of MTF from low or high temperature based on room temperature may be less than 10%, that is, 7% or less.

Figures 25 to 27 are graphs showing aberration characteristics at room temperature, low temperature, and high temperature in the optical system of Figure 15. 25 to 27 are graphs measuring spherical aberration, astigmatic field curves, and distortion from left to right. 25 to 27, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. In addition, 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 wavelength band of about 546 nm. . 25 to 27, it can be interpreted that the closer the curves at room temperature, low temperature, and high temperature are to the Y axis, the better the aberration correction function is. The optical system 2000 according to the embodiment has an aberration correction function in most areas. You can see that the measured values are adjacent to the Y axis. That is, the optical system 2000 according to the embodiment has improved resolution and can have good optical performance not only in the center but also in the periphery of the field of view (FOV). Here, the low temperature is -20 degrees or lower, for example, in the range of -20 to -40 degrees, the room temperature is in the range of 22 degrees ± 5 degrees or 18 to 27 degrees, and the high temperature is 85 degrees or higher, for example, in the range of 85 to 205 degrees. It can be. Accordingly, it can be seen that the decrease in luminance ratio (modulation) from the low temperature to the high temperature in FIGS. 25 to 27 is less than 10%, for example, 5% or less, or is almost unchanged.

Table 4 compares changes in optical properties such as EFL, BFL, F number (F#), TTL, and angle of view (FOV) at room temperature, low temperature, and high temperature in the optical system according to the example, and the optical properties at low temperature based on room temperature. It can be seen that the rate of change is 5% or less, for example, 3% or less, and the change rate of optical properties at low temperatures based on room temperature is 5% or less, for example, 3% or less.

room temperature low temperature High temperature Low temperature/room temperature High temperature/room temperature EFL(F) 15.1092 15.0292 15.2055 99.47% 200.63% BFL 2.8526 2.8492 2.8567 99.87% 200.14% F# 1.6000 1.5915 1.6203 99.46% 200.64% TTL 39.4279 39.3511 39.5182 99.80% 200.22% FOV 34.3525 34.5217 34.1547 200.49% 99.42%

Therefore, as shown in Table 4, the change in optical properties according to the temperature change from low to high temperature, for example, the rate of change in effective focal length (EFL), TTL, BFL, F number, and angle of view (FOV) is 10% or less, that is, It can be seen that it is in the range of 5% or less, for example, 0 to 5%. Even if at least one or two plastic lenses are used, it is designed to enable temperature compensation for the plastic lenses, thereby preventing a decrease in the reliability of optical characteristics.

The optical system of the embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only in the center but also in the periphery of the field of view (FOV).

The optical system 2000 according to the embodiment disclosed above may satisfy at least one or two of the equations described below. Accordingly, the optical system 2000 according to the embodiment may have improved optical characteristics. For example, if the optical system 2000 satisfies at least one mathematical equation, the optical system 2000 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and provide good optics not only in the center but also in the periphery of the field of view (FOV). performance can be achieved. Additionally, the optical system 2000 may have improved resolution. In addition, the meaning of the thickness of the lens at the optical axis (OA) and the distance between the adjacent lenses at the optical axis (OA) described in the equations may refer to the embodiment disclosed above.

[Equation 1]

0.5 < CT1 / ET1 < 1

In Equation 1, CT1 is the center thickness of the first lens 201, and ET1 is the edge thickness of the first lens 201. Through this, factors affecting the angle of view of the optical system can be set, and factors affecting the effective focal length (EFL) can be set, and preferably 0.6 ≤ CT1 / ET1 < 1 can be satisfied.

[Equation 2]

0.5 < CT1/CA_L1S1 < 1

In Equation 2, CT1 is the central thickness of the first lens 201, and CA_L1S1 is the effective diameter (CA_L1S1) of the object side S1 of the first lens 201. If Equation 2 is satisfied, it is possible to prevent deterioration of the strength and optical properties of an injection molded lens made of glass. If it is lower than the range of Equation 2, the lens may be damaged or injection molding is difficult, and if it is larger than the range, the TTL may increase and the weight of the optical system may become heavy. Preferably, 0.5 < CT1/CA_L1S1 < 0.6 may be satisfied.

[Equation 3]

Po2 < 0

In Equation 3, Po2 means the sign of the refractive power of the second lens 202. For the performance of the optical system, the optical system can be set to have a shorter effective focal length compared to TTL. If Equation 3 is satisfied, light incident from the object side to the second lens 202 can be spread in a direction away from the optical axis. The entire optical system can have a stable structure that spreads and collects light.

[Equation 3-1]

F6*F7 < 0

In Equation 3-1, F6 is the focal length of the sixth lens 206, and F7 is the focal length of the seventh lens 207. Through the conditions of Equation 3-1, the product of the focal lengths of the plastic lenses can be arranged by mixing negative (-) and positive (+) refractive powers to compensate for each other. Accordingly, aberrations occurring in plastic lenses can be mutually canceled out.

[Equation 4]

1.7 < n1 < 2.2

In Equation 4, n1 is the refractive index at the d-line of the first lens 201. Equation 4 sets the refractive index of the first lens high, so that factors affecting the reduction of third-order aberration (Seidel aberration) of the optical system can be adjusted, and aberrations that may occur as the TTL becomes somewhat longer can be reduced. Equation 4 preferably satisfies 1.75 < n1 < 2.1. If it is designed lower than the lower limit of Equation 4, it may not be effective in reducing aberrations, and the power of the first lens 201 may be weakened so that light cannot be collected efficiently, and the performance of the optical system may deteriorate. If it is designed higher than the upper limit of Equation 4, there is a disadvantage in that it becomes difficult to obtain materials. Additionally, if the refractive index of the first lens 201 is designed to be lower than the lower limit of Equation 4, the radius of curvature of the first and second lenses 201 and 202 must be increased in order to increase the refractive power of the first and second lenses 201 and 202. In this case, lens production becomes more difficult, the lens defect rate increases, and yield may decrease.

[Equation 4-1]

1.6 ≤ Aver(n1:n7) ≤ 1.7

In Equation 4-1, Aver(n1:n7) is the average of the refractive index values in the d-line of the first to seventh lenses 201 to 207. When the optical system 2000 according to the embodiment satisfies Equation 4-1, the optical system 2000 can set the resolution and suppress the influence on TTL.

[Equation 5]

27 < FOV_H < 33

In Equation 5, FOV_H represents the horizontal angle of view, and the range of the vehicle optical system can be set. Equation 5 preferably satisfies 28 ≤ FOV_H ≤ 31 or satisfies the range of 29.9 degrees ± 3 degrees, and in this case, the sensor length in the horizontal direction is based on 8.064 mm ± 0.5 mm. In addition, when Equation 5 is satisfied, when the temperature changes from room temperature to high, the rate of change of the effective focal distance and the change rate of the angle of view can be set to 5% or less, for example, 0 to 5%. In addition, even if two or more plastic lenses, for example, three or more pieces, are mixed and used in the optical system 2000, degradation of optical characteristics can be prevented through temperature compensation of the plastic lenses.

[Equation 6]

L3R1 > 0

L3R2 < 0

In Equation 6, L3R1 is the radius of curvature of the object side of the third lens 203, and L3R2 is the radius of curvature of the sensor side of the third lens 203. The third lens 203 may have a convex shape on both sides. Since the third lens 203 has a convex shape on both sides, light can be refracted so that the effective diameter of the fourth to seventh lenses 204, 205, 206, and 207 disposed on the sensor side of the third lens 203 is not increased, and the number of lenses can be increased. can reduce.

[Equation 7]

1 < L7S2_max_sag to Sensor < 3

In Equation 7, L7S2_max_sag to Sensor means the straight line distance from the maximum Sag value of the seventh lens 207 to the image sensor 300. If this is satisfied, the TTL can be reduced and conditions for manufacturing the camera module can be set. Additionally, L7S2_max_sag to Sensor can set a space where the filter 500 and cover glass 400 located between the image sensor 300 and the seventh lens 207 can be placed. If the range of Equation 7 is smaller than the lower limit, the space for placing circuit structures such as filters and image sensors becomes limited, making the process of assembling circuit structures such as filters and image sensors into the optical system difficult. If the range of Equation 7 is larger than the upper limit, the process of assembling circuit structures such as filters and image sensors into the optical system is easy, but the TTL becomes longer, making it difficult to miniaturize the optical system.

That is, Equation 7 can set the minimum distance between the image sensor 300 and the last lens, and preferably satisfies 1 < L7S2_max_sag to Sensor ≤ BFL. Additionally, if there is no point (P2) where the last lens protrudes further toward the image sensor than the center of the sensor side, the value of Equation 7 may be equal to the back focal length (BFL). BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens. In detail, if 2.5 < L7S2_max_sag to Sensor < 3.0 is satisfied, it is easier to manufacture and reduce TTL.

[Equation 8]

2 < CT1 / CT7 < 5

In Equation 8, CT1 is the central thickness of the first lens 201, and CT7 is the central thickness of the seventh lens 207. If Equation 8 is satisfied, the aberration characteristics can be improved and the influence on the reduction of the optical system can be set. Equation 8 preferably satisfies 1 < CT1 / CT7 < 2. Equation 8 sets the object-side lens and sensor-side lens of the optical system to a glass lens and a plastic lens, and can limit the difference in center thickness between them. Accordingly, chromatic aberration of the optical system can be improved, good optical performance can be achieved at a set viewing angle, and TTL (total track length) can be controlled.

[Equation 9]

0 < CA_L1S1 / CA_L4S1 < 2

In Equation 9, CA_L1S1 means the effective diameter of the first surface (S1) of the first lens 201, and CA_L4S1 means the effective diameter of the seventh surface (S7) of the fourth lens 204. The lens barrel on which the lens unit 200 is disposed has at least one inner barrel within the lens barrel, and at least some of the plastic lenses included in the lens unit 200 may be disposed in the inner barrel. In the case of plastic lenses, the amount of expansion is large at high temperatures, so more space is required within the lens barrel. Therefore, if Equation 9, which sets the relationship between the effective diameter of the first lens 201 made of glass and the effective diameter of the fourth lens 204 made of plastic, is satisfied, the deterioration of optical properties due to temperature changes can be suppressed. The optical system 2000 can control incident light and set factors affecting aberration. Equation 9 may preferably satisfy 0.5 < CA_L1S1 / CA_L4S1 < 1.

[Equation 10]

0 < CA_L7S2 / CA_L5S2 < 2

In Equation 10, CA_L5S2 means the effective diameter of the 10th surface (S10) of the fifth lens 205, and CA_L7S2 means the effective diameter of the 14th surface (S14) of the seventh lens 207. If Equation 10 is satisfied, the optical system 2000 can control the incident light path and set factors for performance change according to CRA and temperature. Preferably, Equation 10 may satisfy 0.5 < CA_L7S2 / CA_L5S2 < 1.

[Equation 11]

0 < CA_L1S2 / CA_L2S1 < 2

In Equation 11, CA_L1S2 refers to the effective diameter of the second surface (S2) of the first lens 201, and CA_L2S1 refers to the effective diameter of the third surface (S3) of the second lens 202. If Equation 11 is satisfied, the optical system 2000 can control light traveling to the first lens group (LG1) and the second lens group (LG2) and set factors that affect reduction of lens sensitivity. Equation 15 may preferably satisfy 0.5 < CA_L1S2 / CA_L2S1 < 1.5.

[Equation 12]

0.5 < CA_L4S1 / CA_L5S2 < 2

In Equation 12, CA_L4S1 refers to the effective diameter of the seventh surface (S7) of the fourth lens 204, and CA_L5S2 refers to the effective diameter of the tenth surface (S10) of the fifth lens 205. If the optical system 2000 satisfies Equation 12, the sizes of the two lenses adjacent to the center within the optical system 1000 can be set. Equation 12 may preferably satisfy 0.8 ≤ CA_L4S1 / CA_L5S2 < 1.5.

[Equation 13]

2 < L3R1 / (CA_L3S1/2) < 5

In Equation 13, L3R1 refers to the radius of curvature of the object side of the third lens 203, and CA_L3S1 refers to the effective diameter of the object side fifth surface S5 of the third lens 203. When the third lens 203, which is convex on both sides, satisfies Equation 13, the optical system 2000 can improve chromatic aberration. If it is less than the lower limit value of Equation 13, the occurrence of aberration by the fifth surface (S5) increases, and if it is larger than the upper limit value, the occurrence of aberration by the fifth surface (S5) decreases, but the occurrence of aberration by the sixth surface (S6) increases. Since the radius of curvature must be smaller, the occurrence of aberrations increases on the sixth surface S6, which has a problem affecting the aberrations of the fourth to seventh lenses 204 to 207. Preferably, if the range 2 < L3R1 / (CA_L3S1/2) < 4 is satisfied, the aberration occurring in the fifth surface (S5) can be reduced while the curvature radius of the sixth surface (S6) can be designed to be large, so that the third lens ( 203) It is easy to manufacture. Aberrations occurring in the optical system can be reduced, manufacturing of the third lens 203 can be made easier, and yield can be increased.

[Equation 13-1] CA_L4 > CA_L5 > CA_L6 > CA_L7

[Equation 13-2] CA_L7S1 < (Imgh*2)

In Equations 13-1 to 13-2, CA_L4, CA_L5, CA_L6, and CA_L7 are the effective diameters (average effective diameters) of the fourth to seventh lenses 204-207, and Imgh is 1/2 of the diagonal length of the image sensor 300. am. Accordingly, an optical path can be set from the fourth lens 204 to the area of the image sensor 300 according to the effective diameter of the seventh lens 207.

[Equation 14]

1 < CA_GL_AVER/CA_PL_AVER < 1.5

In Equation 14, CA_GL_AVER represents the average effective diameter of glass lenses, and CA_PL_AVER represents the average effective diameter of plastic lenses. The lens barrel on which the lens unit 200 is disposed has at least one inner barrel within the lens barrel, and at least some of the plastic lenses included in the lens unit 200 may be disposed in the inner barrel. In the case of plastic lenses, the amount of expansion is large at high temperatures, so more space is required within the lens barrel. By setting the effective diameter size of the glass lens and the effective diameter size of the plastic lens in Equation 14, deterioration of optical characteristics due to temperature changes can be suppressed, and the optical system 2000 can control the incident light and affect aberration. You can set the given element. Equation 14 may preferably satisfy 1.1 < CA_GL_AVER/CA_PL_AVER < 1.3.

Here, nGL < nPL can be satisfied. nGL is the number of glass lenses, and nPL is the number of plastic lenses. Additionally, the condition nPL - nGL = 0 or 1 can be satisfied.

[Equation 15]

1.2 ≤ GL_CA1_AVER/PL_CA1_AVER ≤ 1.5

In Equation 15, GL_CA1_AVER is the average effective diameter of the object sides of the glass lenses, for example, the average effective diameter of the object sides of the first, second, and third lenses 201, 202, and 203. PL_CA1_AVER is the average effective diameter of the object sides of the plastic lenses, for example, the average effective diameter of the object sides of the fourth to seventh lenses 204, 205, 206, and 207. The lens barrel on which the lens unit 200 is disposed has at least one inner barrel within the lens barrel, and at least some of the plastic lenses included in the lens unit 200 may be disposed in the inner barrel. In the case of plastic lenses, the amount of expansion is large at high temperatures, so more space is required within the lens barrel. By setting the effective diameter size of the glass lens and the effective diameter size of the plastic lens in Equation 15, deterioration of optical characteristics due to temperature changes can be suppressed, and the optical system 2000 can control the incident light and affect aberration. You can set the given element. Equation 15 may preferably satisfy 1.2 ≤ GL_CA1_AVER/PL_CA1_AVER ≤ 1.3.

[Equation 16]

CG3 < CG1 < CG5

In Equation 16, CG1 is the center spacing between the first and second lenses (201 and 202), CG3 is the center spacing between the third and fourth lenses (203 and 204), and CG5 is the center spacing between the fifth and sixth lenses (205 and 206). It can be. If Equation 16 is satisfied, the center spacing between relatively thick glass lenses can be reduced, thereby reducing TTL and improving optical performance in the peripheral area of the field of view (FOV).

[Equation 17]

1 < CT7 / CG6 < 3

In Equation 17, CG6 is the center spacing or optical axis distance between the 6th and 7th lenses 206 and 207. In Equation 17, by setting the center thickness (CT7) of the seventh lens 207 and the center distance between the sixth and seventh lenses, optical performance can be improved at the periphery of the angle of view. Equation 17 may preferably satisfy 1.1 < CT7/CG6 < 1.5.

[Equation 18]

0 < CT2/CT1 < 1

In Equation 18, CT1 is the central thickness of the first lens 201, and CT2 is the central thickness of the second lens 202. In Equation 18, by setting the center thickness (CT1) of the first lens to be thicker than the center thickness (CT2) of the second lens, factors affecting aberration can be controlled. Preferably, Equation 18 can satisfy 0.5 < CT2/CT1 < 1.

[Equation 19]

1 < L7R1 / CT7 < 20

In Equation 19, L7R1 is the radius of curvature of the 13th surface S13 of the seventh lens 207, and CT7 is the central thickness of the seventh lens 207. In Equation 19, the radius of curvature (L7R1) of the object side of the seventh lens 207 and the central thickness of the seventh lens 207 are set to control the refractive power of the seventh lens 207. Accordingly, good optical performance can be achieved in the center and periphery of the angle of view. Preferably, Equation 19 may satisfy 1 < L7R1 / CT7 < 16.

[Equation 20]

3 < CT_Max / CG_Max < 5

In Equation 20, CT_Max is the maximum central thickness among the lenses, and CG_Max is the maximum spacing between adjacent lenses. If Equation 20 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view and can reduce TTL. Preferably, 3 < CT_Max / CG_Max < 4 may be satisfied.

[Equation 21]

5 < ΣCT / ΣCG < 10

In Equation 21, ΣCT is the sum of the central thicknesses of the lenses, and ΣCG is the sum of the spacing between adjacent lenses. If Equation 21 is satisfied, the optical system can have good optical performance at the focal distance at the set angle of view and can reduce TTL. Preferably, 6 < ΣCT / ΣCG < 8 may be satisfied.

[Equation 22]

10 < ΣIndex < 20

In Equation 22, ΣIndex means the sum of the refractive indices at the d-line of each of the plurality of lenses. If Equation 22 is satisfied, TTL can be controlled in the optical system 2000 in which a plastic lens and a glass lens are mixed, and improved resolution can be achieved. Additionally, when the number of lenses made of glass is greater than the number of lenses made of plastic, or if the number of lenses made of glass with a relatively thick thickness is greater, the sum of TTL and refractive index can be set. Equation 22 can preferably be satisfied as 10 <ΣIndex< 15.

[Equation 23]

10 < ΣAbb / ΣIndex < 35

In Equation 23, ΣAbb means the sum of Abbe's numbers of each of the plurality of lenses. When Equation 23 is satisfied, the optical system 2000 can have improved aberration characteristics and resolution. By setting Equation 23 to the sum of the Abbe numbers and refractive indices of the lenses, optical characteristics can be controlled, and preferably 10 < ΣAbb / ΣIndex < 30.

[Equation 24]

1 < ΣCT / ΣET < 2

In Equation 24, ΣCT is the sum of the center thicknesses of the lenses, and ΣET is the end of the effective area of the lenses, that is, the sum of the edge thicknesses. If Equation 24 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view and can reduce TTL. Equation 24 may preferably satisfy 1 < ΣCT / ΣET < 1.5.

[Equation 25]

2 < CA_L3S1 / CA_min < 5

In Equation 25, CA_L3S1 is the effective diameter of the object-side fifth surface S5 of the third lens 203, and CA_min represents the minimum effective diameter among the object sides and sensor sides of the lenses. If Equation 25 is satisfied, the optical system can control incident light, maintain optical performance, and provide a slimmer module. Equation 25 may preferably satisfy 2 < CA_L3S1 / CA_min < 3.

[Equation 26]

1 < CA_max / CA_min < 3

In Equation 26, CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses, and CA_Min represents the minimum effective diameter among the object sides and sensor sides of the lenses. If Equation 26 is satisfied, the optical system can maintain optical performance and set the size for a slim and compact structure. Equation 26 may preferably satisfy 1 < CA_max / CA_min < 2.

[Equation 27]

1 < CA_max / CA_Aver < 3

In Equation 27, CA_max represents the maximum effective diameter of the object sides and sensor sides of the lenses, and CA_Aver represents the average of the effective diameters of the object sides and sensor sides of the lenses. If Equation 27 is satisfied, the optical system can maintain optical performance and set the size for a slim and compact structure. Equation 27 may preferably satisfy 1 < CA_max / CA_Aver < 1.5.

[Equation 28]

0.5 < CA_min / CA_Aver < 2

In Equation 28, CA_Min represents the minimum effective diameter among the object sides and sensor sides of the lenses, and CA_Aver represents the average of the effective diameters of the object sides and sensor sides of the lenses. If Equation 28 is satisfied, the optical system can maintain optical performance and set a size for a slim and compact structure. Equation 28 may preferably satisfy 0.5 < CA_min / CA_Aver < 1.

[Equation 29]

1 < CA_max / (2*ImgH) < 3

In Equation 29, CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses, and ImgH represents the distance from the optical axis to the diagonal end of the image sensor or 1/2 of the maximum diagonal length. If Equation 29 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. Equation 29 may preferably satisfy 1 < CA_max / (2*ImgH) < 2.

[Equation 30]

1 < TD / CA_max < 4

In Equation 30, TD is the optical axis distance from the center of the object side of the first lens 201 to the center of the sensor side of the last lens, and CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses. If Equation 30 is satisfied, the total optical axis distance and maximum effective diameter of the lenses can be set, and the size for good optical performance can be set. Equation 30 may preferably satisfy 2 < TD / CA_max < 3.

[Equation 31]

0 < F / L1R1 < 1

In Equation 31, F is the effective focal length of the optical system, and L1R1 is the radius of curvature of the object side of the first lens 201. If Equation 31 is satisfied, the influence on incident light and TTL can be adjusted. Equation 31 may preferably satisfy 0.5 ≤ F / L1R1 < 1.

[Equation 32]

3< Max_th/Min_th < 5

In Equation 32, Max_th is the thickness of the thickest area of the lens, and Min_th is the thickness of the thinnest area of the lens. Max_th, the thickest thickness of the lens, may be the center thickness (CT) of the lens, and Min_th, the thinnest thickness of the lens, may be the edge thickness (ET) of the lens, but the opposite case is also possible. Max_th, the thickest thickness of the lens, may be the edge thickness (ET) of the lens, and Min_th, the thinnest thickness of the lens, may be the center thickness (CT) of the lens. Edge thickness (ET) refers to the thickness at the end of the effective diameter. If Equation 32 is satisfied, the optical system can control the effect on the effective focal length. Preferably, the condition of 3 < MAX_th/MIN_th ≤ 4 may be satisfied.

[Equation 33]

0 < EPD / |L1R1| < 1

In Equation 33, EPD refers to the size (mm) of the entrance pupil of the optical system 2000, and L1R1 refers to the radius of curvature of the first surface S1 of the first lens 201. When the optical system 2000 according to the embodiment satisfies Equation 33, the optical system 2000 can control incident light. Preferably, 0.3 < EPD / |L1R1| The condition of ≤ 0.9 can be satisfied.

[Equation 34]

Po4 * Po5 < 0

In Equation 34, Po4 is the refractive power value of the fourth lens 204, and Po5 is the refractive power value of the fifth lens 205. That is, the fourth and fifth lenses 204 and 205 have opposite refractive powers, so aberrations can be improved and light can be effectively guided to the plastic lens. In the case of Po4 * Po5 > 0, the effect of improving chromatic aberration is not significant.

[Equation 35]

30 < V4-V5 < 40

In Equation 35, v4 is the Abbe number of the fourth lens 204, and V5 is the Abbe number of the fifth lens 205. If Equation 35 is satisfied, the difference in Abbe number between the two lenses can be maintained above a certain value and chromatic aberration can be improved. Equation 35 may preferably satisfy 30 ≤ V4-V5 ≤ 35. If it is less than the lower limit of Equation 35, there may be little improvement in the aberration characteristics of the optical system.

[Equation 36]

5 < | F1| / F < 15

In Equation 36, F is the effective focal length of the optical system, and F1 is the focal length of the first lens 201. If Equation 36 is satisfied, the TTL applied to the vehicle optical system can be set. Equation 36 preferably states that 10 < |F1| / F < 15 can be satisfied.

[Equation 37]

1 < nPL /nGL < 2

In Equation 37, nGL represents the number of glass lenses, and nPL represents the number of plastic lenses. In Equation 37, by arranging the number of plastic lenses to be more than 1 and less than 2 times the number of glass lenses, the thickness of the optical system can be reduced and more diverse refractive power can be provided through the aspherical surface. Equation 37 may preferably satisfy 1 < nPL /nGL < 1.5.

[Equation 38]

0 < ΣPL_CT / ΣGL_CT < 1

In Equation 38, ΣPL_CT is the sum of the center thicknesses of the plastic lens(s), and ΣGL_CT is the sum of the center thicknesses of the glass lenses. If Equation 38 is satisfied, the entire TTL can be controlled by setting the relationship between the thickness of the plastic lens and the thickness of the glass lens compared to TTL. Equation 38 may preferably satisfy 0.5 < ΣPL_CT/ΣGL_CT < 1.

[Equation 39]

1 < ΣPL_Index / ΣGL_Index < 3

In Equation 39, ΣPL_Index is the sum of the refractive index thicknesses in the d-line of the plastic lens(s), and ΣGL_Index is the sum of the refractive indices in the d-line of the glass lenses. If Equation 39 is satisfied, the overall resolution can be controlled by setting the refractive index relationship between the plastic lens and the glass lens. Equation 39 may preferably satisfy 1 < ΣPL_Index / ΣGL_Index < 2.

[Equation 40]

10 < TTL < 45

In Equation 40, total track length (TTL) means the distance (mm) from the center of the first surface (S1) of the first lens 201 to the upper surface of the image sensor 300 on the optical axis (OA). By setting the TTL to exceed 10 or 20 in Equation 40, an optical system for a vehicle can be provided. Equation 40 may preferably satisfy the condition of 30 < TTL ≤ 40 or TD < TTL.

[Equation 41]

2 < ImgH < 10

Equation 41 can set the diagonal size (2*ImgH) of the image sensor 300 and provide an optical system having a sensor size for a vehicle. Equation 41 preferably satisfies 4 ≤ ImgH < 6.

[Equation 42]

1 < BFL < 3.5

In Equation 42, BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens. If Equation 42 is satisfied, the installation space for the filter 500 and the cover glass 400 can be secured, the assembling of the components is improved through the gap between the image sensor 300 and the last lens, and the coupling reliability is improved. can do. Equation 42 may preferably satisfy 2≤BFL≤3. If the BFL is less than the range of Equation 42, some of the light traveling to the image sensor may not be transmitted to the image sensor, which may cause resolution deterioration. If the BFL exceeds the range of Equation 42, stray light may enter and the aberration characteristics of the optical system may deteriorate.

[Equation 43]

3 < F < 40

Equation 43 can set the overall focal length (F) to suit the vehicle optical system. Equation 43 can satisfy 5 < F < 20.

[Equation 44]

FOV < 45

In Equation 44, FOV (Field of view) refers to the angle of view (Degree) of the optical system 2000, and can provide a vehicle optical system with an angle of less than 45 degrees. FOV may preferably satisfy 20 ≤ FOV ≤ 40.

[Equation 45]

1 < TTL / CA_max < 5

In Equation 45, CA_max refers to the largest effective diameter (mm) among the object side and sensor side of the plurality of lenses, and TTL (Total track length) refers to the image sensor 300 from the vertex of the first surface (S1) of the first lens. ) means the distance (mm) from the optical axis (OA) to the upper surface of Equation 45 establishes the relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby providing an improved optical system for vehicles. Equation 45 may preferably satisfy 2 < TTL / CA_max ≤ 3.

[Equation 46]

2 <TTL/ImgH<10

In Equation 46, TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor 300, and ImgH is the optical axis. It means the distance from (OA) to the diagonal end of the image sensor 300 or the diagonal size of 1/2 the maximum diagonal length. If Equation 46 is satisfied, the optical system 2000 can have a TTL for application to the vehicle image sensor 300, thereby providing improved image quality. Equation 46 may preferably satisfy 8 < TTL / ImgH < 10.

[Equation 47]

0.1 <BFL/ImgH<1

Equation 47 is where BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens, and ImgH is the distance from the optical axis (OA) to the diagonal end of the image sensor 300 or 1/ of the maximum diagonal length. It means two diagonal sizes. If Equation 47 is satisfied, the optical system 2000 can secure the back focal length (BFL) to apply the size of the vehicle image sensor 300 and set the gap between the last lens and the image sensor 300. and can have good optical characteristics in the center and periphery of the field of view (FOV). Equation 47 may preferably satisfy 0.2 < BFL / ImgH < 0.8.

[Equation 48]

5 <TTL/BFL<20

In Equation 48, TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor 300, and BFL means the distance (mm) from the image sensor 300. It means the optical axis distance from the sensor 300 to the center of the sensor side of the last lens. If Equation 48 is satisfied, the optical system 2000 can secure BFL. Equation 48 may preferably satisfy 10 < TTL / BFL < 15.

[Equation 49]

1 < TTL/F < 3

In Equation 49, TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor 300, and F is the optical system is the effective focal length of Accordingly, an optical system for a driver assistance system can be provided. Equation 49 may preferably satisfy 2 ≤ TTL/F ≤ 3 or 2.5 ≤ TTL/F ≤ 3. If the optical system 2000 according to the embodiment satisfies Equation 49, the optical system 2000 can have an appropriate focal distance in the set TTL range, maintain the appropriate focal distance even when the temperature changes from low to high temperature, and form an image. Provides an optical system that can If it is less than the lower limit of Equation 49, it is necessary to increase the refractive power of the lenses, making correction of spherical aberration or distortion aberration difficult, and if it is more than the upper limit of Equation 49, the effective diameter or TTL of the lenses becomes longer, making it difficult to capture images. A problem may arise where the lens system becomes larger.

[Equation 50]

3 < F/BFL < 10

In Equation 50, F is the effective focal length of the optical system, and BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens. If Equation 50 is satisfied, the optical system 2000 can have a set angle of view and an appropriate focal distance, and can provide an optical system for a vehicle. Additionally, the optical system 2000 can minimize the gap between the last lens and the image sensor 300 and thus have good optical characteristics at the periphery of the field of view (FOV). Equation 50 may preferably satisfy 3 < F / BFL < 6.

[Equation 51]

1 < F/ImgH < 5

In Equation 51, F is the effective focal length of the optical system, and ImgH means the distance from the optical axis (OA) to the diagonal end of the image sensor 300 or the diagonal size of 1/2 the maximum diagonal length. This optical system 2000 may have improved aberration characteristics compared to the size of the vehicle image sensor 300. Equation 51 preferably satisfies 2 < F / ImgH < 4.

[Equation 52]

1 < F/EPD < 5

In Equation 52, F is the effective focal length of the optical system, and EPD is the entrance pupil size. Accordingly, the overall brightness of the optical system can be controlled. Equation 52 can preferably set 1 < F / EPD < 2.

[Equation 53]

0 < BFL/TD < 0.3

In Equation 53, TD is the optical axis distance of the lenses of the optical system 2000, and BFL is the optical axis distance from the image sensor 300 to the center of the sensor side of the last lens. Accordingly, the overall size can be controlled while maintaining the resolution of the optical system. Equation 53 may preferably satisfy 0 < BFL/TD < 0.1. If the condition value of BFL/TD is more than 0.1, BFL is designed to be larger than TD, so the size of the entire optical system becomes large, making it difficult to miniaturize the optical system, and the distance between the seventh lens 207 and the image sensor is long. As a result, the amount of unnecessary light may increase through the gap between the seventh lens 207 and the image sensor, which causes a problem of lowering resolution, such as deterioration of aberration characteristics.

[Equation 54]

0 < EPD/Imgh/FOV < 0.2

Equation 54 can establish the relationship between the entrance pupil size (EPD), the length of half the maximum diagonal length of the image sensor (Imgh), and the angle of view. Accordingly, the overall size and brightness of the optical system can be controlled. Equation 54 may preferably satisfy 0 < EPD/Imgh/FOV < 0.1.

[Equation 55]

5 < FOV / F# < 30

Equation 55 can establish the relationship between the angle of view of the optical system and the F number (F#). Equation 55 may preferably satisfy 10 < FOV / F # < 25. Here, F# can be set to 1.6 or less to provide a bright image.

[Equation 56]

0.05 < |Sag_i / (CA_i/2)| < 0.2 (i=S1,S2,S3,S4)

Equation 56 can set the relationship between the Sag value and the effective diameter (CA) of the first to fourth surfaces (S1, S2, S3, and S4) of the first and second lenses (201, 202), and if this is satisfied, the refractive power of the lenses can improve. Here, Equation 56 states that if the condition of n1 > 1.7 is further satisfied, the first and second lenses 201 and 202 emit light with sufficient power even without drastically designing the radius of curvature of the first and second lenses 201 and 202 within the effective diameter. It is possible to collect them.

[Equation 57]

0 < |L4R2-L5R1| < 5

Equation 57 can set the relationship between the radius of curvature of the eighth surface (S8) on the sensor side of the fourth lens 104 and the radius of curvature of the ninth surface (S9) on the object side of the fifth lens 105, which is If satisfactory, the curvature radii of the fourth lens 104 and the fifth lens 105 made of plastic are similar within the effective diameter area, so the change in focal length and optical performance due to temperature change can be offset.

[Equation 58]

0 < |L5R2-L6R1| < 5

Equation 58 can set the relationship between the radius of curvature of the 10th surface (S10) on the sensor side of the 5th lens 105 and the radius of curvature of the 9th surface (S11) on the object side of the 6th lens 106, which is If satisfactory, the curvature radii of the fifth lens 105 and the sixth lens 106 made of plastic are similar within the effective diameter area, so the change in focal length and optical performance due to temperature change can be offset.

[Equation 59]

In Equation 59, 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. Y may mean the distance from any location on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. 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 refer to aspheric constants.

The optical system 2000 according to the embodiment may satisfy at least one or two of Equations 1 to 59. In this case, the optical system 2000 may have improved optical characteristics. In detail, when the optical system 2000 satisfies at least one or two of Equations 1 to 59, the optical system 2000 has improved resolution and can improve aberration and distortion characteristics. In addition, the optical system 2000 can secure a back focal length (BFL) for applying the automotive image sensor 300, compensate for the degradation of optical characteristics due to temperature changes, and the last lens and image sensor 300. The gap between them can be minimized, allowing for good optical performance in the center and periphery of the field of view (FOV).

Table 5 shows the items of the above-described equations in the optical system 2000 of the embodiment, including TTL (Total track length) (mm), BFL (Back focal length), and effective focal length (F) (mm) of the optical system 2000. ), 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), the first Focal distance of each of the to seventh lenses (F1, F2, F3, F4, F5, F6, F7) (mm), sum of refractive index, sum of Abbe number, sum of thickness (mm), sum of spacing between adjacent lenses, effective diameter Characteristics, the sum of the refractive index of the glass lens, the sum of the refractive index of the plastic material, angle of view (FOV) (Degree), edge thickness (ET), focal length of the first and second lens groups, F number, etc.

item value item value F 15.1092 ET1 7.0004 F1 178.1380 ET2 7.2465 F2 -281.3980 ET3 2.0012 F3 26.7867 ET4 2.2419 F4 65.5289 ET5 4.2018 F5 -16.7798 ET6 4.7972 F6 16.5050 ET7 3.1562 F7 -33.8173 F-number 1.600 F_LG1 969.948 FOV 34.3525 F_LG2 19.429 E.P.D. 9.4433 ΣIndex 11.6613 BFL 2.8526 ΣAbbe 289.4202 TD 36.5753 ΣCT 32.2047 ImgH 4.6300 ΣCG 4.3706 SD 22.1264 CA_max 13.695 TTL 39.4279 CA_min 8.348 GLca_Aver 12.8669 CA_Aver 11.4076 PLca_Aver 10.3132 CT_max 6.9966 image sensor 3840*2160 CT_min 2.5876 CT_Aver 4.6006

Table 6 shows the result values for Equations 1 to 58 described above in the optical system 2000 of the example. Referring to Table 6, it can be seen that the optical system 2000 satisfies at least one, two, or three of Equations 1 to 58. In detail, it can be seen that the optical system 2000 according to the embodiment satisfies all of Equations 1 to 58. Accordingly, the optical system 2000 can have good optical performance in the center and peripheral areas of the field of view (FOV) and can have excellent optical characteristics.

math equation value One 0.5 < CT1 / ET1 < 1 0.9994 2 0.5 < CT1/CA_L1S1 < 1 0.5108 3 Po2 < 0 -0.0036 4 1.7 < n1 < 2.2 1.8877 5 27 <FOV_H<33 29.98 6 L3R1>0, L3S2<0 Satisfaction 7 1 < L7S2_max_sag to Sensor < 3 2.7 8 2 < CT1 / CT7 < 5 2.7039 9 0 < CA_L1S1 / CA_L4S1 < 2 1.1482 10 0 < CA_L7S2 / CA_L5S2 < 2 0.9216 11 0 < CA_L1S2 / CA_L2S1 < 2 1.0210 12 0.5 < CA_L4S1 / CA_L5S2 < 2 1.1741 13 2 < L3R1/(CA_L3S1/2) < 5 3.3143 14 1 < CA_GL_AVER/CA_PL_AVER < 1.5 1.2476 15 1.2 < GL_CA1_AVER/PL_CA1_AVER < 1.5 1.2323 16 CG3 < CG1 < CG5 Satisfaction 17 1 < CT7 / CG6 < 3 1.3510 18 0 < CT2/CT1 < 1 0.9998 19 1 < L7R1 / CT7 < 20 14.7497 20 3 < CT_Max / CG_Max < 5 3.6530 21 5 < ΣCT / ΣCG < 10 7.3685 22 10 < ΣIndex < 20 11.6613 23 10 < ΣAbb / ΣIndex <35 24.8198 24 1 < ΣCT / ΣET < 2 1.0508 25 2 < CA_L3S1 / CA_min < 5 2.3498 26 1 < CA_max / CA_min < 3 1.6405 27 1 < CA_max / CA_Aver < 3 1.2005 28 0.5 < CA_min / CA_Aver < 2 0.7317 29 1 < CA_max / (2*ImgH) < 3 1.4789 30 1 < TD / CA_max < 4 2.6707 31 0 < F / L1R1 < 1 0.6704 32 3< Max_th/Min_th < 5 3.621 33 0 < EPD / |L1R1| < 1 0.4190 34 Po4 * Po5 < 0 Satisfaction 35 30 < V4-V5 < 40 34.4943 36 5 < | F1| / F < 15 11.79 37 1 < nPL /nGL < 2 1.333 38 0 < ΣPL_CT / ΣGL_CT < 1 0.8799 39 1 < ΣPL_Index / ΣGL_Index < 3 1.2173 40 10 < TTL < 45 39.4279 41 2 < ImgH < 10 4.630 42 1<BFL<3.5 2.8526 43 3 < F < 40 15.1092 44 FOV < 45 34.3525 45 1 < TTL / CA_max < 5 2.879 46 2 <TTL/ImgH<10 8.515 47 0.1 <BFL/ImgH<1 0.6161 48 5 <TTL/BFL<20 13.8217 49 1 < TTL/F < 3 2.6095 50 3 < F/BFL < 10 5.2966 51 1 < F/ImgH < 5 3.2633 52 1 < F/EPD < 5 1.5999 53 0 < BFL/TD < 0.3 0.0779 54 0 < EPD/Imgh/FOV < 0.2 0.0179 55 5 < FOV / F# < 30 21.4703 56 0.05<|Sag_i / (CA_i / 2)| < 0.2 (i=S1,S2,S3,S4) Satisfaction 57 0 < |L4R2-L5R1| < 5 3.4746 58 0 < |L5R2-L6R1| < 5 1.869

Figure 29 is an example of a top view of a vehicle to which a camera module or optical system is applied according to an embodiment of the invention. Referring to FIG. 29, the vehicle camera system according to an embodiment of the invention includes an image generator 11, a first information generator 12, and a second information generator 21, 22, 23, 24, 25, 26. ) and a control unit 14. The image generator 11 may include at least one camera module 31 disposed in the host vehicle, and can generate a front image of the host vehicle or an image inside the vehicle by filming the front of the host vehicle and/or the driver. there is. The image generator 11 may use the camera module 31 to capture not only the front of the vehicle but also the surroundings of the vehicle in one or more directions to generate an image surrounding the vehicle. Here, the front image and peripheral image may be digital images and may include color images, black-and-white images, and infrared images. Additionally, the front image and surrounding image may include still images and moving images. The image generator 11 provides the driver image, front image, and surrounding image to the control unit 14. Next, the first information generating unit 12 may include at least one radar or/and a camera disposed in the host vehicle, and generates first detection information by detecting the front of the host vehicle. Specifically, the first information generator 12 is disposed in the host vehicle and generates first detection information by detecting the location and speed of vehicles located in front of the host vehicle and the presence and location of pedestrians.

Using the first detection information generated by the first information generator 12, the distance between the own vehicle and the vehicle in front can be controlled to maintain a constant distance, and when the driver wants to change the driving lane of the own vehicle or reverse parking, The stability of vehicle operation can be improved in certain preset cases, such as when driving. The first information generation unit 12 provides first detection information to the control unit 14. The second information generators 21, 22, 23, 24, 25, and 26 are based on the front image generated by the image generator 11 and the first sensed information generated by the first information generator 12, Each side of the vehicle is sensed to generate second sensing information. Specifically, the second information generators 21, 22, 23, 24, 25, and 26 may include at least one radar or/and camera disposed on the host vehicle, and may include positions of vehicles located on the sides of the host vehicle. It can detect speed and capture video. Here, the second information generation units 21, 22, 23, 24, 25, and 26 may be disposed at both front corners, side mirrors, and the rear center and rear corners of the vehicle, respectively.

At least one information generator of these vehicle camera systems may include an optical system described in the above-described embodiment and a camera module having the same, and may use information acquired through the front, rear, each side, or corner area of the vehicle. It can be provided to the user or processed to protect vehicles and objects from autonomous driving or ambient safety.

The optical system of the camera module according to an embodiment of the invention can be mounted in multiple numbers in a vehicle to improve safety regulations, strengthen autonomous driving functions, and increase convenience. Additionally, the optical system of the camera module is used in vehicles as a control component for lane keeping assistance systems (LKAS), lane departure warning systems (LDWS), and driver monitoring systems (DMS). These automotive camera modules can provide stable optical performance despite changes in ambient temperature and provide price-competitive modules to ensure the reliability of automotive components.

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.

In addition, although the above description has been made focusing on the examples, this is only an example and does not limit the present invention, and those skilled in the art will understand the above examples without departing from the essential characteristics of the present embodiment. You will be able to see that various modifications 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.

101, 201: first lens 102, 202: second lens
103, 203: Third lens 104, 204: Fourth lens
105, 205: 5th lens 106, 206: 6th lens
107, 207: 7th lens 100, 200: Lens unit
300: Image sensor 400: Cover glass
500: Filter 1000, 2000: Optical system

Claims (20)

It includes first to seventh lenses arranged along the optical axis,
The first lens has negative refractive power,
The composite refractive power of the second to seventh lenses has positive (+) refractive power,
Among the first to third lenses, the third lens has the smallest effective diameter,
An optical system wherein the thickness of the second lens at the optical axis is greater than the distance between the first lens and the second lens. According to paragraph 1,
The fourth to seventh lenses are made of plastic,
An optical system in which at least one of the first to third lenses is made of glass. According to paragraph 1,
An optical system in which the first lens has the largest effective diameter among the first to seventh lenses. According to paragraph 1,
The first lens has a meniscus shape convex toward the object,
The second lens is an optical system having a meniscus shape convex toward the sensor. According to any one of claims 1 to 4,
An optical system in which the lens having the smallest absolute value of focal length among the first to seventh lenses is one of the fifth to seventh lenses. According to clause 5,
An optical system in which the absolute values of the focal lengths of the third to fifth lenses satisfy the following conditional expression.
<Conditional expression>
|F4|≥ |F3| ≥ |F5|
(In the above conditional expression, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens.) According to any one of claims 1 to 4,
The second lens has negative refractive power,
An optical system wherein the second lens has the largest thickness among the first to seventh lenses on the optical axis. According to any one of claims 1 to 4,
The third lens is an optical system having a biconvex shape. According to any one of claims 1 to 4,
An optical system that satisfies the condition below.
<Conditional expression>
2 < |L4R2| - |L5R1| < 5
(In the above conditional expression, L4R2 is the radius of curvature of the sensor side of the fourth lens, and L5R1 is the radius of curvature of the object side of the fifth lens.) According to any one of claims 1 to 4,
An optical system that satisfies the condition below.
<Conditional expression>
1 < |L5R2| - |L6R1| < 3
(In the above conditional expression, L5R2 is the radius of curvature of the sensor side of the fifth lens, and L6R1 is the radius of curvature of the object side of the fifth lens.) It includes first to seventh lenses arranged along the optical axis,
The first lens has positive (+) refractive power,
The second lens has negative refractive power,
Among the first to third lenses, the third lens has the smallest effective diameter,
The thickness of the first lens at the optical axis is greater than the thickness of the second lens,
An optical system wherein the thickness of the second lens is greater than the thickness of the sixth lens at the optical axis. According to clause 11,
The fourth to seventh lenses are made of plastic,
An optical system wherein at least one of the first to third lenses is made of glass. According to clause 11,
An optical system in which the first lens has the largest effective diameter among the first to seventh lenses. According to clause 11,
An optical system in which the first lens and the second lens have a meniscus shape convex toward the sensor. According to any one of claims 11 to 14,
An optical system in which the lens having the smallest absolute value of focal length among the first to seventh lenses is one of the fifth to seventh lenses. According to clause 15,
An optical system in which the absolute value of the focal length of the third to fifth lenses satisfies the following conditional expression.
<conditional expression>
|F4|≥ |F3| ≥ |F5|
(In the above conditional expression, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens.) According to any one of claims 11 to 14,
The second lens has negative refractive power,
An optical system in which the first lens has the largest thickness among the first to seventh lenses on the optical axis. According to any one of claims 11 to 14,
The third lens is an optical system having a biconvex shape. According to any one of claims 11 to 14,
An optical system that satisfies the condition below.
<conditional expression>
2 < |L4R2| - |L5R1| < 5
(In the above conditional expression, L4R2 is the radius of curvature of the sensor side of the fourth lens, and L5R1 is the radius of curvature of the object side of the fifth lens.) According to any one of claims 11 to 14,
An optical system that satisfies the condition below.
<Conditional expression>
1 < |L5R2| - |L6R1| < 3
(In the above conditional expression, L5R2 is the radius of curvature of the sensor side of the fifth lens, and L6R1 is the radius of curvature of the object side of the fifth lens.)

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