Optical system and imaging device module

Abstract

An optical system according to an embodiment of the present invention comprises, in order from an object side to a sensor side: a first lens; a second lens; a third lens having a negative (-) refractive power; a fourth lens having a negative (-) refractive power; a fifth lens having a positive (+) refractive power; and a sixth lens having a positive (+) refractive power; a seventh lens; and an eighth lens having a positive (+) refractive power, in which, among the first to eighth lenses, the second lens has the highest refractive index.

Description

Technical Field

[0001] The present invention relates to an optical system for enhancing optical performance and a camera device module including the optical system. Background Technology

[0002] Advanced Driving Assistance Systems (ADAS) are advanced driver assistance systems that assist drivers in driving. They are configured to sense the situation ahead, assess the situation based on the sensed information, and control the vehicle's behavior based on the assessment. For example, ADAS sensors detect vehicles ahead and identify the lane. Then, after determining the target lane, target speed, and the target ahead, it controls the vehicle's Electrical Stability Control (ESC), Engine Management System (EMS), and Motor Driven Power Steering (MDPS). Typical examples of ADAS implementations include automatic parking systems, low-speed city driving assistance systems, and blind spot warning systems.

[0003] Sensor devices used in ADAS to detect the situation ahead include GPS sensors, laser scanners, front radar, LIDAR, etc., and the most representative device is the camera device used to capture images of the front, rear, and sides of the vehicle.

[0004] These cameras can be installed either outside or inside the vehicle to detect the surrounding environment. Furthermore, they can be installed inside the vehicle to monitor the driver and passengers. For example, cameras can film the driver from a location near the driver and detect their health condition, whether they are drowsy, or whether they have been drinking. Similarly, cameras can film passengers from a location near them and detect whether they are sleeping, their health condition, etc., providing the driver with information about the passengers.

[0005] In particular, the most important element in acquiring an image from a camera device is the imaging lens that forms the image. Recently, there has been increasing focus on high performance, such as high definition and high resolution, and optical systems incorporating multiple lenses are being researched to achieve this. However, a problem exists where the characteristics of the optical system change when the camera device is exposed to harsh environments, such as high temperatures, low temperatures, humidity, or high humidity, both outside and inside a vehicle. In such cases, it becomes difficult for the camera device to uniformly achieve excellent optical and aberration characteristics.

[0006] Therefore, new optical systems and imaging devices are needed to solve the above problems. Summary of the Invention

[0007] Technical topics

[0008] This embodiment aims to provide an optical system and camera module with enhanced optical properties.

[0009] This embodiment aims to provide an optical system and camera module with excellent optical performance in low-temperature to high-temperature environments.

[0010] This embodiment aims to provide an optical system and camera module that can prevent changes in optical properties over various temperature ranges or minimize changes in optical properties over various temperature ranges.

[0011] Technical solutions

[0012] To solve the above-mentioned technical problems, the optical system according to an embodiment of the present invention comprises, from the object side to the sensor side, the following in sequence: a first lens; a second lens; a third lens having negative (-) refractive power; a fourth lens having negative (-) refractive power; a fifth lens having positive (+) refractive power; a sixth lens having positive (+) refractive power; a seventh lens; and an eighth lens having positive (+) refractive power, wherein, among the first to eighth lenses, the second lens has the highest refractive index.

[0013] The second lens is made of glass, and the third lens can be made of plastic.

[0014] The first and seventh lenses have negative (-) refractive power, and the second lens can have positive (+) refractive power.

[0015] The distance between the first and second lenses on the optical axis can be greater than the distance between the fifth and sixth lenses.

[0016] Among the first to eighth lenses, the fourth lens has the largest absolute value of focal length.

[0017] The distance between the third and fourth lenses on the optical axis can be greater than the distance between the seventh and eighth lenses.

[0018] It includes a first lens group and a second lens group. The first lens group includes a first lens to a fifth lens, and the second lens group includes a sixth lens to an eighth lens. The composite focal length of the first lens group can be smaller than the composite focal length of the second lens group.

[0019] It includes a first lens group and a second lens group. The first lens group includes a first lens to a fifth lens, and the second lens group includes a sixth lens to an eighth lens. The sign of the composite focal length of the first lens group and the sign of the composite focal length of the second lens group may be different.

[0020] It includes a first lens group and a second lens group. The first lens group includes a first lens to a fifth lens, and the second lens group includes a sixth lens to an eighth lens. The absolute value of the difference between the absolute value of the composite focal length of the first lens group and the absolute value of the focal length of the second lens group can satisfy 1 or greater and 5 or less.

[0021] The following conditional expression can be satisfied: <conditional expression> 1.7 < n2 < 1.9 (In the above conditional expression, n2 represents the refractive power of the second lens)

[0022] The following conditional expression can be satisfied: 20 < v2 < 30 (In the above conditional expression, v2 represents the Abbe number of the second lens).

[0023] The following conditional expression can be satisfied: <conditional expression> 110 < FOV_H < 150 (In the above conditional expression, FOV_H refers to the horizontal angle of view of the optical system).

[0024] The following conditional expression can be satisfied. <Conditional expression> 8 < TTL / ImgH < 9 (In the above conditional expression, TTL refers to the distance on the optical axis from the center of the object-side surface of the first lens to the upper surface of the image sensor, and ImgH refers to 1 / 2 of the maximum diagonal length of the image sensor)

[0025] To solve the above-mentioned technical problems, an optical system according to another embodiment of the present invention includes, in order from the object side to the sensor side: a first lens; a second lens; a third lens having negative (-) refractive power; a fourth lens having negative (-) refractive power; a fifth lens; a sixth lens; a seventh lens having negative (-) refractive power; and an eighth lens having positive (+) refractive power, wherein the distance between the first lens and the second lens on the optical axis may be greater than the distance between the fifth lens and the sixth lens.

[0026] An aperture is set between the fifth and sixth lenses. The fifth lens is made of glass and can have a positive (+) refractive power.

[0027] Among the first to eighth lenses, the second lens can have the highest refractive index.

[0028] The first and second lenses are made of glass, and the sixth through eighth lenses may be made of plastic.

[0029] Among the first to seventh lenses, the fourth lens has the largest absolute value of focal length.

[0030] It includes a first lens group and a second lens group. The first lens group includes a first lens to a fifth lens, and the second lens group includes a sixth lens to an eighth lens. The composite focal length of the first lens group can be smaller than the composite focal length of the second lens group.

[0031] It includes a first lens group and a second lens group. The first lens group includes a first lens to a fifth lens, and the second lens group includes a sixth lens to an eighth lens. The absolute value of the difference between the absolute value of the composite focal length of the first lens group and the absolute value of the focal length of the second lens group can satisfy 1 or greater and 5 or less.

[0032] Beneficial effects

[0033] The optical system and camera module according to the embodiments can have enhanced optical characteristics. Specifically, in the optical system according to the embodiments, the multiple lenses can have a set thickness, refractive power, and gaps between adjacent lenses. Therefore, the optical system and camera module according to the embodiments can have enhanced MTF characteristics, aberration control characteristics, resolution characteristics, etc., within a set viewing angle range, and can have good optical performance at the edges of the viewing angle.

[0034] Furthermore, the optical system and camera module according to the embodiments can exhibit good optical performance within a low-temperature to high-temperature range (-40°C to 105°C). Specifically, the multiple lenses included in the optical system can have specific materials, refractive indices, and refractive powers. Therefore, when the refractive index of each lens changes with temperature and the focal length of each lens also changes accordingly, this can be compensated for by the plastic lenses and glass lenses. In other words, the optical system can effectively perform refractive power distribution within a low-temperature to high-temperature range and can prevent or minimize changes in optical properties within this range. Therefore, the optical system and camera module according to the embodiments can maintain enhanced optical properties across a variety of temperature ranges.

[0035] Furthermore, the optical system and camera module according to the embodiments can achieve the desired viewing angle and excellent optical characteristics by combining plastic lenses and glass lenses. As a result, the optical system can provide a thinner vehicle camera module. Therefore, the optical system and camera module can be provided for various applications and devices, and can exhibit excellent optical characteristics even in harsh temperature environments, such as when exposed to the exterior of a vehicle or the interior of a vehicle under high summer temperatures. Attached Figure Description

[0036] Figure 1This is a side cross-sectional view of the optical system according to the first embodiment and the camera device module having the optical system.

[0037] Figure 2 This is a table showing the aspherical coefficient values ​​and conic constant (k) of each lens surface in the optical system according to the first embodiment.

[0038] Figure 3 This is a table showing the thickness of each lens and the spacing between adjacent lenses in an optical system according to the first embodiment.

[0039] Figure 4 This is a table showing the sag values ​​of each lens surface in the optical system according to the first embodiment.

[0040] Figure 5 This is a table showing the tilt angle values ​​of each lens surface in the optical system according to the first embodiment.

[0041] Figure 6 It is a graph showing the diffraction MTF (modulation transfer function) data of the optical system according to the first embodiment at room temperature.

[0042] Figure 7 It is a graph showing data on the aberration characteristics of the optical system according to the first embodiment at room temperature.

[0043] Figure 8 This is a graph showing the diffraction MTF data of the optical system according to the first embodiment at low temperature.

[0044] Figure 9 It is a graph showing the aberration characteristics of the optical system according to the first embodiment at low temperature.

[0045] Figure 10 This is a graph showing the diffraction MTF data of the optical system according to the first embodiment at high temperature.

[0046] Figure 11 It is a graph showing the aberration characteristics of the optical system according to the first embodiment at high temperatures.

[0047] Figure 12 This is a cross-sectional side view of the optical system according to the second embodiment and the camera device module including the optical system.

[0048] Figure 13 This is a table showing the aspherical coefficient values ​​and conic constant (k) of each lens surface in the optical system according to the second embodiment.

[0049] Figure 14This is a table showing the thickness of each lens and the spacing between adjacent lenses in the optical system according to the second embodiment.

[0050] Figure 15 This is a table showing the sag values ​​of each lens surface in the optical system according to the second embodiment.

[0051] Figure 16 This is a table showing the tilt angle values ​​of each lens surface in the optical system according to the second embodiment.

[0052] Figure 17 It is a graph showing the diffraction MTF (modulation transfer function) data of the optical system according to the second embodiment at room temperature.

[0053] Figure 18 It is a graph showing the aberration characteristics of the optical system according to the second embodiment at room temperature.

[0054] Figure 19 This is a graph showing the diffraction MTF data of the optical system according to the second embodiment at low temperature.

[0055] Figure 20 It is a graph showing the aberration characteristics of the optical system according to the second embodiment at low temperature.

[0056] Figure 21 This is a graph showing the diffraction MTF data of the optical system according to the second embodiment at high temperature.

[0057] Figure 22 It is a graph showing the aberration characteristics of the optical system according to the second embodiment at high temperatures.

[0058] Figure 23 This is a cross-sectional side view of the optical system according to the third embodiment and the camera device module including the optical system.

[0059] Figure 24 This is a table showing the aspherical coefficient values ​​and conic constant (k) of each lens surface in the optical system according to the third embodiment.

[0060] Figure 25 This is a table showing the thickness of each lens and the spacing between adjacent lenses in an optical system according to the third embodiment.

[0061] Figure 26 This is a table showing the sag values ​​of each lens surface in the optical system according to the third embodiment.

[0062] Figure 27This is a table showing the tilt angle values ​​of each lens surface in the optical system according to the third embodiment.

[0063] Figure 28 It is a graph showing the diffraction MTF (modulation transfer function) data of the optical system according to the third embodiment at room temperature.

[0064] Figure 29 It is a graph showing the aberration characteristics of the optical system according to the third embodiment at room temperature.

[0065] Figure 30 This is a graph showing the diffraction MTF data of the optical system according to the third embodiment at low temperature.

[0066] Figure 31 It is a graph showing the aberration characteristics of the optical system according to the third embodiment at low temperature.

[0067] Figure 32 This is a graph showing the diffraction MTF data of the optical system according to the third embodiment at high temperature.

[0068] Figure 33 It is a graph showing the aberration characteristics of the optical system according to the third embodiment at high temperatures.

[0069] Figure 34 This is an example of a vehicle having an optical system according to an embodiment of the present invention. Detailed Implementation

[0070] In the following, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0071] However, the technical concept of the present invention is not limited to the few embodiments described, but can be implemented in various forms, and within the scope of the technical concept of the present invention, one or more of the constituent elements can be selectively combined or substituted between embodiments.

[0072] Furthermore, unless explicitly defined and described, the terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as meanings that can be normally understood by those skilled in the art, and commonly used terms (e.g., terms defined in dictionaries) may be interpreted in the context of the relevant art.

[0073] Furthermore, the terminology used in this specification is for the purpose of describing embodiments and is not intended to limit the invention. In this specification, unless explicitly stated in the phrase, the singular form may include the plural form, and when described as “at least one (or more than one) of A, B, and C,” it may include one or more of all combinations that can be combined with A, B, and C.

[0074] Furthermore, when describing components of embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used.

[0075] These terms are intended only to distinguish components from other components, and they do not restrict the nature, order, or sequence of components.

[0076] Furthermore, when a component is described as being “connected,” “coupled,” or “interconnected” to another component, the component is not only directly connected, coupled, or interconnected to the other component, but may also include cases where the component is “connected,” “coupled,” or “interconnected” due to other components between it and the other component.

[0077] Furthermore, when described as being formed or positioned "above" or "below" each component, "above" or "below" means that it includes not only the case where two components are in direct contact, but also the case where one or more other components are formed or positioned between the two components. Additionally, when expressed as "above" or "below," it can include the meaning of both an upward and downward direction relative to a component.

[0078] In the description of this invention, "object-side surface" can refer to the surface of the lens facing the object side relative to the optical axis (OA), while "sensor-side surface" can refer to the surface of the lens facing the imaging surface (image sensor) relative to the optical axis. "Object-side surface" can be "object side," while "sensor-side surface" can be "image side." A convex surface of the lens can refer to a convex shape in the optical axis or paraxial region, while a concave surface of the lens can refer to a concave shape in the optical axis or paraxial region. The radius of curvature, center thickness, and optical axis clearance between lenses described in the lens data table can refer to values ​​on the optical axis (unit: mm). "Vertical direction" can refer to a direction perpendicular to the optical axis, and the end of the lens or lens surface can refer to the end of the effective area of ​​the lens through which incident light passes. Depending on the measurement method, the effective diameter of the lens surface can have a measurement error of up to ±0.4 mm. The aforementioned paraxial region refers to a very narrow region near the optical axis, and is a region where the distance light travels from the optical axis (OA) is almost zero. In the following text, the optical axis direction may refer to the center of each lens or a very narrow area near the optical axis direction.

[0079] The effective diameter can be the diameter of the effective region where effective light is incident in each lens. The effective diameter is the length in the direction orthogonal to the optical axis (X, Y), and is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. "Diameter of the lens surface" can mean "effective diameter of the lens." "Lens diameter" can be the diameter of the entire lens, including not only the effective region but also the flange portion. Although the lens flange is not shown in the figures, it can be a portion formed by protruding from the side surface of the lens in a direction perpendicular to the optical axis, allowing the lens to be attached to the lens barrel. Effective light may not be incident on the flange. Spacers can be additionally provided between the flanges of different lenses to attach the lenses to the lens barrel.

[0080] Each lens may include an effective region and an ineffective region. The effective region can be the area through which light incident on each lens passes. In other words, the effective region can be defined as an effective area or effective diameter through which incident light is refracted to achieve optical properties. The ineffective region may be located around the effective region. The ineffective region can be the area where effective light does not incident on multiple lenses. In other words, the ineffective region can be a region unrelated to optical properties. Furthermore, the end portion of the ineffective region may be an area fixed to the lens barrel or similar structure housing the lens.

[0081] like Figure 1 , Figure 12 and Figure 23 As shown, the optical systems (1000, 1100, 1200) according to the first to third embodiments of the present invention may include seven or more lenses. The optical systems (1000, 1100, 1200) and the camera module having the optical systems (1000, 1100, 1200) can be installed inside or outside a vehicle to monitor the driver or sense external objects or lanes. The lens material can be selected from glass or plastic, and the linear expansion coefficient of glass is lower than that of plastic. Therefore, glass lenses are used to suppress changes in the focal imaging position due to temperature variations. However, glass lenses are more expensive than plastic lenses, and there is a problem in meeting low-cost requirements. Therefore, the lenses in the optical systems (1000, 1100, 1200) need to have a hybrid configuration of glass and plastic lenses. By using these plastic lenses, the optical systems (1000, 1100, 1200) can be made lighter and cheaper by reducing the thickness of the plastic lenses, and the plastic lenses can provide excellent correction for various aberrations such as spherical aberration and chromatic aberration. Furthermore, since plastic lenses can provide aspherical lenses, distortion in the edge portions can be minimized.

[0082] The optical system (1000, 1100, 1200) may include n lenses, where the nth lens may be the last lens adjacent to the image sensor (400), and the (n-1)th lens may be the lens closest to the last lens. n is an integer greater than or equal to 7, for example, 7 to 9. The n lenses may have a glass-to-plastic lens ratio in the range of 2:6 to 3:5.

[0083] Within the optical system (1000, 1100, 1200), at least one lens closest to the object can be made of glass. Two or fewer lenses closest to the object, such as two lenses, can also be made of glass. Because glass lenses exhibit a smaller rate of contraction and expansion due to temperature changes than plastic lenses, glass lenses can be placed in the region adjacent to the exterior of the lens barrel.

[0084] At least one lens adjacent to the stop position within the optical system (1000, 1100, 1200) can be made of glass. The lens closest to the stop position on the object side of the stop can also be made of glass. Since the lens adjacent to the stop position has a significant impact within the optical system (1000, 1100, 1200), glass lenses can be used to minimize the rate of change in contraction and expansion due to temperature variations.

[0085] At least one lens within the optical system (1000, 1100, 1200) closest to the image sensor (400) can be made of plastic. For example, at least two lenses closest to the image sensor (400) can be made of plastic, and preferably, at least two lenses adjacent to the image sensor (400) can be made of plastic. That is, since the nth and (n-1)th lenses in the optical system (1000, 1100, 1200) are set as plastic lenses, various aberrations can be corrected for the light incident on the image sensor (400).

[0086] Within the optical system (1000, 1100, 1200), plastic lenses can be arranged continuously, and glass lenses can be arranged sequentially. Within the optical system (1000, 1100, 1200), plastic lenses can be arranged between glass lenses. Within the optical system (1000, 1100, 1200), glass lenses can be arranged between plastic lenses.

[0087] Each of the lenses (101 to 108, 201 to 208, 301 to 308) can have an object-side surface and a sensor-side surface. In the optical system, the number of lenses with aspherical sensor-side surfaces and aspherical object-side surfaces can be greater than the number of plastic lenses. In the optical system, the number of lenses with spherical sensor-side surfaces and spherical object-side surfaces can be less than the number of lenses with aspherical surfaces on both sides. Because the optical system (1000, 1100, 1200) is equipped with more aspherical lenses than spherical lenses, various aberrations can be corrected.

[0088] In the lenses of the optical system (1000, 1100, 1200), the lens with the maximum refractive index can be positioned close to the object. The maximum refractive index can be 1.7 or greater. The lens with the maximum refractive index can increase the dispersion of incident light, and the center thickness can be thinner than the edge thickness. Furthermore, since the lens with the maximum refractive index is positioned 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.

[0089] like Figure 1 , Figure 12 and Figure 23 As shown, the optical systems (1000, 1100, 1200) according to the first to third embodiments of the present invention may include a plurality of lens groups (LG1, LG2). Specifically, each of the plurality of lens groups (LG1, LG2) includes at least one lens. For example, the optical system (1000, 1100, 1200) may include a first lens group (LG1) and a second lens group (LG2) arranged sequentially along the optical axis (OA) from the object side toward the image sensor (400). The optical system (1000, 1100, 1200) may include n lenses, wherein the nth lens is the last lens, and the (n-1)th lens may be the lens closest to the last lens. n is an integer of 5 or greater, and may be, for example, 5 to 8.

[0090] The optical system (1000, 1100, 1200) may include a first lens group (LG1) and a second lens group (LG2). The first lens group (LG1) consists of multiple lenses positioned on the object side relative to the aperture (STOP), and the second lens group (LG2) consists of multiple lenses positioned on the sensor side relative to the aperture (STOP). The number of lenses in the first lens group (LG1) and the second lens group (LG2) may be different from each other. The number of lenses in the first lens group (LG1) may be greater than the number of lenses in the second lens group (LG2). Alternatively, the number of lenses in the first lens group (LG1) and the number of lenses in the second lens group (LG2) may be the same.

[0091] The first lens group (LG1) may include at least one lens. The first lens group (LG1) may have five or fewer lenses. Preferably, the first lens group (LG1) may consist of five lenses. The second lens group (LG2) may include three or more lenses. The second lens group (LG2) may consist of three lenses.

[0092] The compound focal length of the first lens group (LG1) can be defined as F_LG1, and the compound focal length of the second lens group (LG2) can be defined as F_LG2, where the signs of F_LG1 and F_LG2 can be different from each other. F_LG1 can have a negative (-) value, and F_LG2 can have a positive (+) value. With this configuration, light can be diverged by one of the two lens groups and then converged by the other lens group. The absolute value of the compound focal length of the first lens group (LG1) and the absolute value of the compound focal length of the second lens group (LG2) can satisfy a range of 1 or greater and 5 or less. When this condition is met, the yield during the manufacturing of the optical system (1000, 1100, 1200) can be improved, and the tolerance can be reduced.

[0093] The aperture (STOP) is set between the fifth lens (105, 205, 305) and the sixth lens (106, 206, 306). The first lens group (LG1) includes the first to fifth lenses (101 to 105, 201 to 205, 301 to 305), and the second lens group (LG2) may include the sixth to eighth lenses (106 to 108, 206 to 208, 306 to 308). The compound focal length of the first lens group (LG1) has a negative (-) sign, and the focal length of at least one of the first lens (101, 201, 301), the third lens (103, 203, 303), and the fourth lens (104, 204, 304) may have the same sign as the focal length of the first lens group (LG1). The Abbe number of the lenses in the first lens group (LG1) that have the same sign as the compound focal length of the first lens group (LG1) may be 40 or greater. The Abbe numbers of the first lens (101, 201, 301) and the third lens (103, 203, 303) can be 40 or greater. This eliminates aberrations in the light passing through each lens. However, the second lens (102, 202, 302), which has a small refractive power, can exceptionally have an Abbe number of 40 or less.

[0094] The compound focal length of the second lens group (LG2) has a positive (+) sign, and the focal length of at least one of the fifth lens (105, 205, 305), the sixth lens (106, 206, 306), and the eighth lens (108, 208, 308) can have the same sign as the focal length of the second lens group (LG2). The Abbe number of the lens in the second lens group (LG2) with the same sign as the compound focal length of the second lens group (LG2) can be 50 or greater. The Abbe number of at least one of the fifth lens (105, 205, 305), the sixth lens (106, 206, 306), and the eighth lens (108, 208, 308) can be 40 or greater. This eliminates aberrations in the light passing through each lens. However, lenses with relatively small refractive power can exceptionally have an Abbe number of 50 or less.

[0095] The lens with the largest effective diameter within the optical system (1000, 1100, 1200) can be positioned closest to the object side. The effective diameter of the lens can increase from the object side toward the sensor side and then decrease. Alternatively, the effective diameter of the lens can decrease from the object side toward the sensor side and then increase. With this configuration, light incident on the optical system (1000, 1100, 1200) converges toward the optical axis and then diverges away from the optical axis, thereby allowing the optical system (1000, 1100, 1200) to form a stable optical path.

[0096] The effective diameter can be the diameter of the effective area on each lens where effective light is incident. The effective diameter is the length in the X and Y directions orthogonal to the optical axis, and is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. "Diameter of the lens surface" can refer to "the effective diameter of the lens." "The diameter of the lens" can also refer to the entire diameter of the lens, including the flange portion in addition to the effective area. Although in Figure 1 , Figure 12 and Figure 23 The lens flange is not shown, but it can be a portion formed by protruding from the side surface of the lens in a direction perpendicular to the optical axis, for attaching the lens to the lens barrel. Effective light may not be incident on the flange. Spacers may be additionally provided between the flanges of different lenses for attaching the lenses to the lens barrel.

[0097] Each of the lenses (101 to 108, 201 to 208, 301 to 308) may include an effective region and an ineffective region. The effective region can be the area through which light incident on each of the lenses passes. That is, the effective region can be defined as the effective area or effective diameter in which incident light is refracted to achieve optical properties. Ineffective regions may be disposed around the effective regions. Ineffective regions can be areas among the multiple lenses where effective light is not incident. That is, ineffective regions can be regions unrelated to optical properties. Furthermore, the ends of the ineffective regions may be areas fixed to the lens barrel, etc., that houses the lenses.

[0098] The edge thickness (ET1 to ET8) of the lens (101 to 108, 201 to 208, 301 to 308) can refer to the thickness at the edge of the effective area. The edge thickness (ET1 to ET8) of the lens (101 to 108, 201 to 208, 301 to 308) can be set relative to the lens surface with the larger effective area among the object-side surface and sensor-side surface of each lens.

[0099] In the optical system (1000, 1100, 1200), the TTL (Total Track Length) can be more than 5 times Imgh, and can be, for example, 6 times or more and 8 times or less than Imgh. TTL (Total Track Length) is the distance along the optical axis (OA) from the center of the object-side surface of the first lens to the imaging surface of the image sensor (400). Imgh is half the maximum diagonal length of the image sensor (400). In the optical system (1000, 1100, 1200), the effective focal length (EFL) is set to 5 mm or more and 6 mm or less, and the horizontal field of view (FOV_H) is set to 110 or more and 150 or less, making it possible to configure it as an optical system for monitoring the interior of a vehicle in a vehicle camera module. For example, the optical system and camera module according to the embodiment can be applied to a camera device for ADAS (Advanced Driver Assistance Systems) located inside or outside a vehicle.

[0100] The TTL / Imgh of the optical system (1000, 1100, 1200) can be 8 or greater and 9 or less, and for example, it can be 1.7 or greater and 2 or less. An optical system for a vehicle lens can be configured by setting the TTL / Imgh value of the optical system (1000, 1100, 1200) to 8.2 or greater and 8.8 or less. Therefore, the optical system (1000, 1100, 1200) can provide an image without exaggeration or distortion for the image being formed.

[0101] In the optical system (1000, 1100, 1200), the effective diameter of at least one plastic lens may be smaller than the length of the image sensor (400). The effective diameter is the diameter or length of the effective region where light is incident. The length of the image sensor (400) is the maximum length of the diagonal in a direction orthogonal to the optical axis (OA). In the optical system (1000, 1100, 1200), the number of lenses with an effective diameter greater than the length of the image sensor (400) may be 10% or greater and 20% or less, and the number of lenses with an effective diameter less than the length of the image sensor (400) may be 70% or greater and 80% or less.

[0102] The lens unit can be a mixture of glass and plastic lenses. The number of plastic lenses can be 70% or more of the total number of lenses, and can range from 65% to 85%. Therefore, when more plastic lenses are placed within the camera module, the weight of the camera module can be reduced, and because it is made of plastic, it is easy to polish and process, has strong external impact resistance, is price-competitive, and the materials are easy to source. In addition, various aberrations can be corrected by plastic lenses, thereby preventing the degradation of optical performance.

[0103] Embodiments of the present invention can reduce the weight of the camera module, provide lower manufacturing costs, suppress the degradation of optical properties due to temperature variations, and allow various types of plastic lenses to replace glass lenses by incorporating more plastic lenses within the optical system (1000, 1100, 1200). Furthermore, polishing and processing of lens surfaces (such as aspherical or freeform surfaces) can be easier.

[0104] The effective diameter of the lens closest to the object side within the lens unit can be larger than the effective diameter of the lens closest to the image sensor (400). This allows for control of the brightness of the optical system. The effective diameter can be the average effective diameter of the object-side surface and the sensor-side surface of each lens. By controlling the size of the effective diameter of each lens, the optical system (1000, 1100, 1200) can control the incident light to compensate for the degradation of optical properties caused by changes in resolution and temperature, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (1000, 1100, 1200).

[0105] The lens unit may include a first lens (101, 201, 301), a second lens (102, 202, 302), a third lens (103, 203, 303), a fourth lens (104, 204, 304), a fifth lens (105, 205, 305), a sixth lens (106, 206, 306), a seventh lens (107, 207, 307), and an eighth lens (108, 208, 308) arranged sequentially along the optical axis from the object side toward the sensor side.

[0106] A lens unit can be disposed within a camera module having an inner endoscope tube on one side or the entire inner surface of the lens barrel. A lens unit can be disposed within a camera module having multiple inner endoscope tubes surrounding the circumference of different lenses within the lens barrel. A lens unit can be disposed within a camera module having a first inner endoscope tube contacting the outer surface of at least one lens and a second inner endoscope tube contacting the outer surface of at least one lens within the lens barrel. A lens unit can be disposed within a camera module having multiple inner endoscope tubes, each disposed between the outer surface of at least one or two or more lenses and the lens barrel. A lens unit can be disposed within a camera module wherein the multiple inner endoscope tubes are made of a material different from that of the lens barrel.

[0107] At least some of the glass lenses constituting the lens unit can be disposed within the lens barrel, and at least some of the plastic lenses can be disposed within an inner lens barrel, which is located within the lens barrel. Thus, the optical system (1000, 1100, 1200) can maintain its resolution despite temperature changes. The lens unit disposed in an imaging device module with different lens barrels (heterogeneous lens barrels) can minimize the eccentricity of lenses (such as plastic lenses) that expand due to temperature changes. By having multiple inner lens barrels within the lens barrel where the lens unit is disposed, the resolution of the optical system can be maintained, and lens deformation due to temperature changes can be suppressed. Therefore, the effective diameter of at least some of the glass lenses included in the lens unit can be smaller than the effective diameter of at least some of the plastic lenses.

[0108] Within the lens unit, one or more (e.g., two or more) lenses larger than the average effective diameter of the plastic lens can exist. When the average effective diameter of the plastic lens is PLca_Aver and the average effective diameter of the glass lens is GLca_Aver, the condition PLca_Aver < GLca_Aver can be satisfied. Additionally, the condition 1 < GLca_Aver / PLca_Aver < 2 can be satisfied. Furthermore, the relationship between the length of the image sensor (400) and the average effective diameter PLca_Aver of the plastic lens can satisfy the condition 1.2 < PLca_Aver / Imgh < 1.8. The difference between half the maximum diagonal length of the image sensor (400) and the effective diameter of the plastic lens can be small. Therefore, by arranging plastic lenses with small effective diameters adjacent to the image sensor (400), the plastic lenses can disperse color from the central portion of the image sensor (400) to the edge portion.

[0109] The average effective diameter of the glass material can be 11 mm or greater, for example, in the range of 12 mm to 13 mm. The average effective diameter of the plastic material can be 7 mm or greater, for example, in the range of 8 mm to 9 mm. The lens with the smallest effective diameter can be made of plastic, and the lens with the largest effective diameter can be made of glass. The smallest effective diameter within the lens unit can be in the range of 6 mm to 7 mm, and the largest effective diameter can be in the range of 17 mm to 20 mm. The plastic lens is designed to have a smaller effective diameter than the glass lens and is configured not to contact the lens barrel, thereby minimizing changes in optical performance due to temperature variations. Furthermore, the optical system (1000, 1100, 1200) can improve resolution and chromatic aberration control characteristics by controlling the incident light, and the vignetting characteristics of the optical system (1000, 1100, 1200) can be improved.

[0110] The optical system (1000, 1100, 1200) or camera module may include an image sensor (400). The image sensor (400) can detect light and convert it into an electrical signal. The image sensor (400) can detect light passing sequentially through the lens unit. The image sensor (400) may include elements capable of detecting incident light, such as a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS).

[0111] The optical system (1000, 1100, 1200) or camera module may include a filter (500). The filter (500) may be positioned between the last lens and the image sensor (400). The filter (500) may also be positioned between the lens closest to the sensor side of the lens unit and the image sensor (400). For example, the filter (500) may be positioned between the nth lens and the image sensor (400).

[0112] The cover glass is positioned between the filter (500) and the image sensor (400), protecting the upper part of the image sensor (400) and preventing a decrease in the reliability of the image sensor (400). The cover glass can be removed. The cover glass can be a protective glass.

[0113] The filter (500) may include an infrared filter or an infrared cutoff filter (IR cutoff). The filter (500) allows light of a defined wavelength band to pass through and filters out light of different wavelength bands. When the filter (500) includes an infrared filter, it can prevent radiant heat emitted from external light from being transferred to the image sensor (400). In addition, the filter (500) allows visible light to pass through and reflects infrared light.

[0114] The optical system (1000, 1100, 1200) according to the embodiment may include an aperture (STOP). The aperture can control the amount of light incident on the optical system (1000, 1100, 1200). In a lens disposed between an object and an aperture, the effective diameter of the lens surface tends to increase from the object side to the aperture. In a lens surface disposed between an aperture and a sensor, the effective diameter of the lens surface tends to decrease from the aperture side to the sensor side. The tendency for the effective diameter of the lens surface to increase or decrease does not simply mean that the effective diameter of the lens surface increases or decreases. For example, it also includes cases where the effective diameter of the lens surface increases from the aperture side to the sensor side and then decreases.

[0115] In the optical systems (1000, 1100, 1200) of the first to third embodiments, the sum of the refractive indices of the lenses in the lens unit can be 10 or greater, for example, in the range of 11 to 14, and the average refractive index can be in the range of 1.5 to 1.7. The sum of the Abbe numbers of each of the lenses can be 340 or greater, for example, in the range of 350 to 370, and the average Abbe number can be 50 or less, for example, in the range of 42 to 47. The sum of the center thicknesses of the entire lens can be 18 mm or greater, for example, in the range of 19 mm to 23 mm, and the average center thickness can be in the range of 2 mm to 3 mm. The sum of the center distances between the lenses on the optical axis (OA) can be 9 mm or greater, for example, in the range of 9 mm to 13 mm, and can be less than the sum of the center thicknesses of the lenses. Furthermore, the average effective diameter of each of the lens surfaces (S1 to S16) of the lens unit can be set to 8 mm or greater, for example, in the range of 9 mm to 10 mm.

[0116] In the optical system according to the first to third embodiments of the present invention, the F-number can be 2 or less, for example, in the range of 1.5 to 1.7. The vehicle optical system can have a horizontal field of view (FOV_H) in the Y-axis direction that can be greater than 110 degrees and less than 150 degrees, for example, in the range of 110 to 130 degrees. Furthermore, a vertical field of view can be set at an angle smaller than the horizontal field of view. The vertical field of view (FOV_V) can be greater than 50 degrees and less than 60 degrees, for example, in the range of 110 to 130 degrees. The sensor length in the horizontal direction Y can be 8.064 mm ± 0.5 mm, and the sensor height in the vertical direction X can be 4.536 mm ± 0.5 mm. The horizontal field of view (FOV_H) is the field of view based on the horizontal length of the image sensor, and the vertical field of view (FOV_V) is the field of view based on the vertical length of the image sensor. Therefore, changes in the focal position due to temperature variations can be suppressed, and various aberrations can be well corrected for use in vehicle imaging devices.

[0117] Because optical systems used in vehicle camera devices typically monitor road conditions, they can be designed based on the horizontal field of view (FOV) rather than the entire field of view. The optical system according to this embodiment is designed with a margin in the inscribed circle of the image sensor. This ensures guaranteed optical performance within the horizontal field of view (FOV_H).

[0118] Since this embodiment is an optical system applied to a vehicle camera device, even if it is designed to use both plastic and glass lenses, the first lens (101, 201, 301) can be made of glass. This is because glass has the advantages of being scratch-resistant and insensitive to external temperatures compared to plastic. The first lens (101, 201, 301) can have a spherical surface and be made of glass.

[0119] The second lens (102, 202, 302), positioned closest to the object side of the plastic lens, can be a glass-molded lens with an aspherical surface and made of glass. A glass-molded lens is manufactured by placing an optical glass ingot into a mold having an aspherical shape, and then heating and compressing the optical glass ingot. The second lens (102, 202, 302), being made of glass-molded lenses, can compensate for changes in optical performance caused by temperature variations.

[0120] To more effectively prevent scratches caused by foreign objects or structures located inside the vehicle, a glass lens can be used as the first lens (101, 201, 301), and the object-side surface of the first lens (101, 201, 301) can have a gently curved shape to avoid contact with external structures. This minimizes the occurrence of scratches due to contact with external structures. For driver monitoring, front / rear camera capture, lane detection, and debris detection around the vehicle while it is being driven, the viewing angle can be greater than 110 degrees and less than 150 degrees, and for example, within the range of 110 to 130 degrees. This horizontal viewing angle can be a preset angle for an advanced driver assistance system (ADAS).

[0121] The optical system (1000, 1100, 1200) according to the embodiment may further include a reflective member for changing the path of light. The reflective member may be implemented as a prism, which reflects light incident on the optical system (1000, 1100, 1200) toward the lens. The optical system according to the embodiment will be described in detail below.

[0122] In the following description, the configuration of an optical system according to a first embodiment of the present invention will be described with reference to the accompanying drawings.

[0123] Figure 1 This is a side cross-sectional view of the optical system according to the first embodiment and the camera device module having the optical system; Figure 2 This is a table showing the aspherical coefficient values ​​and conic constant (k) of each lens surface in the optical system according to the first embodiment; Figure 3 This is a table showing the thickness of each lens and the spacing between adjacent lenses in an optical system according to the first embodiment; Figure 4This is a table showing the sag values ​​of each lens surface in the optical system according to the first embodiment; Figure 5 This is a table showing the tilt angle values ​​of each lens surface in the optical system according to the first embodiment; Figure 6 It is a graph showing the diffraction MTF (modulation transfer function) data of the optical system according to the first embodiment at room temperature; Figure 7 It is a graph showing data on the aberration characteristics of the optical system according to the first embodiment at room temperature; Figure 8 It is a graph showing the diffraction MTF data of the optical system according to the first embodiment at low temperature; Figure 9 It is a graph showing data on the aberration characteristics of the optical system according to the first embodiment at low temperature; Figure 10 It is a graph showing the diffraction MTF data of the optical system according to the first embodiment at high temperature; and Figure 11 It is a graph showing the aberration characteristics of the optical system according to the first embodiment at high temperatures.

[0124] The optical system according to the first embodiment includes a lens unit, and the lens unit may include a first lens (101) to an eighth lens (108). The first lens to the eighth lens (101, 102, 103, 104, 105, 106, 107, 108) may be arranged sequentially along the optical axis (OA). Light corresponding to information about an object may pass through the first lens (101) to the eighth lens (108) and the filter (500) and be incident on the image sensor (400).

[0125] The lens units can be arranged in sequence from the object side to the image side as a first lens (101), a second lens (102), a third lens (103), a fourth lens (104), a fifth lens (105), an aperture (STOP), a sixth lens (106), a seventh lens (107), and an eighth lens (108).

[0126] In another embodiment, one or more of another lens, plate, and optical components may be added between the first lens (101) and the eighth lens (108). Additionally, one or more of another lens, plate, and optical components may be added in front of the first lens (101) or behind the eighth lens (108). Furthermore, one or more of another lens, plate, and optical components may be added between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter (500) may be a plate lens. The refractive power of the plate lens may be '0'. The refractive power of the plate lens may be absent. Additionally, a filter layer may be disposed between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter layer may be coated to form a filter.

[0127] The first lens (101) can be positioned closest to the object side. The first lens (101) can be positioned furthest from the sensor side. The first lens (101) can have a negative (-) refractive power on the optical axis (OA). The first lens (101) can comprise a plastic material or a glass material, and can be made of, for example, glass. A first lens (101) made of glass can reduce changes in the center position and radius of curvature caused by temperature variations in the surrounding environment, and can protect the incident-side surface of the optical system (1000).

[0128] The first surface (S1) on the object side of the first lens (101) may be convex relative to the optical axis, and the second surface (S2) on the sensor side may be concave. The first lens (101) may have a meniscus shape convex toward the object side. The first lens (101) may be made of glass and may have a spherical surface. At least one or both of the first surface (S1) and the second surface (S2) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0129] Due to the refractive properties of the first lens (101), the second lens (102) can be further separated from the first lens (101). That is, the center distance between the first lens and the second lens (101, 102) can be the largest within the lens unit.

[0130] The refractive index (n1) of the first lens (101) can satisfy the condition that n1 > 1.6 or n1 > 1.61. This increases the radius of curvature of both the first and second lenses (101, 102) and facilitates lens manufacturing. If the refractive index (n1) of the first lens (101) is less than this condition, the lens surface must be formed with a sharp concave or convex shape to increase the refractive power of both the first and second lenses (101, 102). In this case, lens manufacturing is not easy, the defect rate of the lens increases, and it may lead to a decrease in yield.

[0131] The second lens (102) can be the second from the object side. The second lens (102) can be the seventh from the sensor side. The second lens (102) can be positioned between the first lens (101) and the third lens (103). The second lens (102) can have a positive (+) refractive power on the optical axis (OA). The second lens (102) can comprise plastic or glass material. For example, the second lens (102) can be made of glass molding material.

[0132] The object-side third surface (S3) of the second lens (102) may be convex relative to the optical axis (OA), and the sensor-side fourth surface (S4) may be concave. The second lens (102) may have a meniscus shape convex toward the object side. The second lens (102) may be made of a glass molding material and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspheric coefficients of the third surface and the fourth surface (S3, S4) may be set to... Figure 2 S1 and S2 of L2 in the middle. At least one or both of the third surface (S3) and the fourth surface (S4) can be set to have no critical point from the end of the optical axis (OA) to the effective region.

[0133] The third lens (103) may be the third from the object side. The third lens (103) may be the sixth from the sensor side. The third lens (103) may be positioned between the second lens (102) and the fourth lens (104). The third lens (103) may have a negative (-) refractive power on the optical axis (OA). The third lens (103) may comprise plastic or glass material. For example, the third lens (103) may be made of plastic material.

[0134] The fifth surface (S5) of the third lens (103) on the object side can be convex relative to the optical axis, and the sixth surface (S6) on the sensor side can be concave. The third lens (103) can have a meniscus shape convex toward the object side. The third lens (103) can be made of plastic material and can be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) can be aspherical. The aspheric coefficients of the fifth surface and the sixth surface (S5, S6) can be set to... Figure 2 S5 and S6 of L3 in the middle.

[0135] The fifth surface (S5) of the third lens (103) may include a critical point from the optical axis (OA) to the end of the effective region. When the fifth surface (S5) has a critical point, it may be located in the range of 90% to 95%, preferably 91% to 95%, of the effective radius (r31) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in the range of 4.5 mm to 4.9 mm, preferably 4.7 mm to 4.8 mm, from the optical axis (OA). The sixth surface (S6) of the third lens (103) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0136] The fourth lens (104) may be the fourth from the object side. The fourth lens (104) may be the fifth from the sensor side. The fourth lens (104) may be positioned between the third lens (103) and the fifth lens (105). The fourth lens (104) may have a positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (104) may have a negative (-) refractive power. The fourth lens (104) may comprise plastic or glass material. For example, the fourth lens (104) may be made of plastic material.

[0137] Relative to the optical axis, the seventh surface (S7) of the fourth lens (104) on the object side can be convex, and the eighth surface (S8) on the sensor side can be concave. The fourth lens (104) can have a meniscus shape convex toward the object side. The fourth lens (104) can have a meniscus shape concave toward the sensor side. The fourth lens (104) can be made of plastic material and can be aspherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) can be aspherical. The aspheric coefficients of the seventh surface and the eighth surface (S7, S8) can be set to... Figure 2 S1 and S2 of L4 in the middle. At least one or both of the seventh surface (S7) and the eighth surface (S8) can be set to have no critical point from the optical axis (OA) to the end of the effective region.

[0138] The fifth lens (105) can be configured as the fifth lens from the object side. The fifth lens (105) can also be configured as the fourth lens from the sensor side. The fifth lens (105) can be positioned between the fourth lens (104) and the sixth lens (106). The fifth lens (105) can have a positive (+) or negative (-) refractive power along the optical axis (OA). The fifth lens (105) can have a positive (+) refractive power. The fifth lens (105) can comprise plastic or glass material. For example, the fifth lens (105) can be made of glass material.

[0139] The ninth surface (S9) on the object side of the fifth lens (105) may be convex relative to the optical axis (OA), and the tenth surface (S10) on the sensor side may be convex. The fifth lens (105) may have a shape with convex sides. The fifth lens (105) may be made of glass and may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0140] The aperture (STOP) can be set around the tenth surface (S10) on the sensor side of the fifth lens (105). The aperture (STOP) can be set around the eleventh surface (S11) on the object side of the sixth lens (106). The aperture can reduce the TTL within the field of view and can miniaturize the optical system. Therefore, it is possible to prevent the yield reduction of the optical system due to weight and to improve production efficiency. In addition, the optical system can be miniaturized by reducing the TTL within a horizontal field of view (FOV_H) of 100 to 130 degrees.

[0141] The sixth lens (106) can be configured as the sixth lens from the object side. The sixth lens (106) can also be configured as the third lens from the sensor side. The sixth lens (106) can be positioned between the fifth lens (105) and the seventh lens (107). The sixth lens (106) can have a positive (+) or negative (-) refractive power along the optical axis (OA). The sixth lens (106) can have a positive (+) refractive power. The sixth lens (106) can comprise plastic or glass material. For example, the sixth lens (106) can be made of plastic material.

[0142] Relative to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (106) may be convex, and the sensor-side twelfth surface (S12) may be convex. The sixth lens (106) may have a convex shape on both sides. The sixth lens (106) may be made of plastic material and may be aspherical. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspheric coefficients of the eleventh and twelfth surfaces (S11, S12) may be set to... Figure 2 S1 and S2 of L6 in the middle. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) can be set to have no critical point from the end of the optical axis (OA) to the effective region.

[0143] The seventh lens (107) can be configured as the seventh lens from the object side. The seventh lens (107) can be configured as the second lens from the sensor side. The seventh lens (107) can be positioned between the sixth lens (106) and the eighth lens (108). The seventh lens (107) can have a positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (107) can have a negative (-) refractive power. The seventh lens (107) can comprise plastic or glass material. For example, the seventh lens (107) can be made of plastic material.

[0144] Relative to the optical axis (OA), the object-side thirteenth surface (S13) of the seventh lens (107) may be convex, and the sensor-side fourteenth surface (S14) may be concave. The seventh lens (107) may have a meniscus shape convex toward the object side. The seventh lens (107) may have a meniscus shape concave toward the sensor side. The seventh lens (107) may be made of plastic material and may be aspherical. At least one or both of the thirteenth surface (S13) and the fourteenth surface (S14) may be aspherical. The aspheric coefficients of the thirteenth and fourteenth surfaces (S13, S14) may be set to... Figure 2 S13 and S14 of L7 in the middle.

[0145] The thirteenth surface (S13) of the seventh lens (107) may include a critical point from the optical axis (OA) to the end of the effective region. When the thirteenth surface (S13) has a critical point, it may be located in the range of 35% to 45%, preferably 38% to 43%, of the effective radius (r71) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in the range of 1.3 mm to 1.7 mm, preferably 1.5 mm to 1.6 mm, from the optical axis (OA). The fourteenth surface (S14) of the seventh lens (107) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0146] The eighth lens (108) can be positioned furthest from the object side. The eighth lens (108) can be positioned closest to the image sensor (500). The eighth lens (108) can have a positive (+) or negative (-) refractive power on the optical axis (OA). The eighth lens (108) can have a positive (+) refractive power. The eighth lens (108) can comprise plastic or glass material. For example, the eighth lens (108) can be made of plastic material.

[0147] The object-side fifteenth surface (S15) of the eighth lens (108) may be convex relative to the optical axis (OA), and the sensor-side sixteenth surface (S16) may also be convex. The eighth lens (108) may have a shape that is convex on both sides. At least one or both of the fifteenth surface (S15) and the sixteenth surface (S16) may be aspherical. The aspheric coefficients of the fifteenth and sixteenth surfaces (S15, S16) may be set to... Figure 2 S15 and S16 of L8 in the middle.

[0148] The fifteenth surface (S15) can be configured to have no critical point at the end of the effective region from the optical axis (OA). The sixteenth surface (S16) of the eighth lens (108) can include a critical point at the end of the effective region from the optical axis (OA). When the sixteenth surface (S16) has a critical point, it can be located in the range of 45% to 55% of the effective radius (r82) from the optical axis (OA), preferably in the range of 50% to 52.5%. The critical point of the fifth surface (S5) can be located in the range of 1.8 mm to 2.3 mm from the optical axis (OA), preferably in the range of 2 mm to 2.1 mm from the optical axis (OA).

[0149] The eighth lens (108) can be the plastic lens closest to the image sensor (500). Furthermore, by arranging two or more plastic lenses adjacent to the image sensor (500), aberrations such as spherical aberration and chromatic aberration can be improved through the lens surface having an aspherical surface, and the impact on resolution can be controlled. Moreover, by arranging the plastic lenses adjacent to the image sensor (500), the plastic lenses can be insensitive to assembly tolerances compared to glass lenses. In other words, insensitivity to assembly tolerances means that even if the assembly differs slightly from the design during assembly, the optical performance may not be significantly affected. Furthermore, by making the two lenses (107, 108) adjacent to the image sensor (500) plastic, the optical performance can be improved through the lens surface having an aspherical surface, and aberration characteristics can be improved, for example, and resolution degradation can be prevented.

[0150] Table 1

[0151]

[0152] Table 1 shows the surface number (“surface”), radius of curvature (“radius”), center thickness of each lens or distance between lens surfaces (“thickness”), refractive index (“nd”), Abbe number (“vd”), effective radius (“semi-aperture”), and focal length (“focal length”) of the lens according to the first embodiment of the present invention. Here, the units for radius of curvature and thickness or distance may be mm.

[0153] Table 2

[0154]

[0155] Table 2 shows the characteristics of the optical system according to the first embodiment of the present invention.

[0156] TTL refers to the optical axis distance from the object-side vertex of the first lens (101) to the imaging surface; SD refers to the optical axis distance from the aperture (STOP) to the image-side surface of the eighth lens (108); TD refers to the optical axis distance from the object-side vertex of the first lens (101) to the image-side surface of the eighth lens (108); F refers to the total focal length; F_LG1 refers to the composite focal length of the first lens (101) to the fifth lens (105) in the object-side direction of the aperture (STOP); F_LG2 refers to the composite focal length of the sixth lens (106) to the eighth lens (108). The composite focal length of the lens (108) in the image-side direction of the aperture (STOP), Fno means the ratio of the focal length of the lens to the effective diameter, ImgH means the distance from the optical axis (OA) to the diagonal end of the image sensor (400) or 1 / 2 of the maximum diagonal length, FOV_H means the horizontal field of view of the optical system, EPD means the diameter of the entrance pupil (effective aperture), BFL means the optical axis distance from the image-side surface of the eighth lens (108) to the imaging surface, and ET1 to ET8 means the thickness of the edge region of each lens.

[0157] The center thicknesses of the first to eighth lenses (101 to 108) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, the center gaps between two adjacent lenses are represented by CG1 to CG7, and the edge gaps between the edges of each lens are represented by EG1 to EG7. BFL (back focal length) is the optical axis distance from the image sensor (500) to the center of the last lens. 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 (500).

[0158] like Figure 2As shown, in the lens unit of the first embodiment, the lens surfaces of the second, third, fourth, sixth, seventh, and eighth lenses (102, 103, 104, 106, 107, 108) may include aspherical surfaces with a 30th-order aspherical surface coefficient. For example, the second, third, fourth, sixth, seventh, and eighth lenses (102, 103, 104, 106, 107, 108) may include lens surfaces with a 30th-order aspherical surface coefficient. As described above, an aspherical surface with a 30th-order aspherical surface coefficient (non-zero value) can significantly alter the aspherical shape of the edge portion, and therefore, can effectively correct the optical performance of the edge portion of the field of view (FOV).

[0159] The thicknesses (T1 to T8) of the first to eighth lenses (101 to 108) and the gaps (G1 to G7) between adjacent lenses can be set. For example... Figure 3 As shown, the thickness of each lens in the Y-axis direction can be expressed with a gap of 0.1 mm or 0.2 mm or greater (T1 to T8), and the gap between each lens can be expressed with each gap of 0.1 mm or 0.2 mm or greater (G1 to G7).

[0160] When comparing the absolute values ​​of the radii of curvature of each lens, on the optical axis (OA), the radius of curvature of the thirteenth surface (S13) of the seventh lens (107) can be the largest among the lenses, and the radius of curvature of the sixth surface (S6) of the third lens (103) can be the smallest among the lenses. The difference between the maximum and minimum radii of curvature can be 60 times or greater, for example, in the range of 70 to 80 times.

[0161] Because the effective diameter of a plastic lens is smaller than that of a glass lens, a lens positioned on the object side of a plastic lens can have a strong refractive force to refract light through the plastic lens. Furthermore, the radius of curvature of the lens surface can be very small to enhance the refractive force.

[0162] The absolute value of the radius of curvature of the first surface (S1) of the first lens (101) can be greater than the absolute value of the radius of curvature of the second surface (S2). The absolute value of the radius of curvature of the third surface (S3) of the second lens (102) can be less than the absolute value of the radius of curvature of the fourth surface (S4). The absolute value of the radius of curvature of the fifth surface (S5) of the third lens (103) can be greater than the absolute value of the radius of curvature of the sixth surface (S6). The absolute value of the radius of curvature of the seventh surface (S7) of the fourth lens (104) can be greater than the absolute value of the radius of curvature of the eighth surface (S8). The absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (105) can be greater than the absolute value of the radius of curvature of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (106) can be less than the absolute value of the radius of curvature of the twelfth surface (S12). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (107) can be greater than the absolute value of the radius of curvature of the fourteenth surface (S14). The absolute value of the radius of curvature of the fifteenth surface (S15) of the eighth lens (108) can be less than the absolute value of the radius of curvature of the sixteenth surface (S16).

[0163] The ratio of the radii of curvature of each lens can satisfy the following condition.

[0164] Condition 1: 2 < |L1R1 / L1R2| < 3

[0165] Condition 2: 0.5 < |L2R1 / L2R2| < 0.8

[0166] Condition 3: 2 < |L3R1 / L3R2| < 3

[0167] Condition 4: 2 < L4R1 / L4R2 < 3

[0168] Condition 5: 1 < |L5R1 / L5R2| < 2

[0169] Condition 6: 0.5 < |L6R1 / L6R2| < 1

[0170] Condition 7: 20 < |L7R1 / L7R2| < 25

[0171] Condition 8: 0.1 < L8R1 / L8R2 < 0.5

[0172] When describing the center thickness (CT) of a lens relative to the optical axis, the center thickness (CT6) of the sixth lens (106) is the largest among the lenses, and the center thickness (CT7) of the seventh lens (107) is the smallest among the lenses. The difference between the largest and smallest center thicknesses among the lenses can be in the range of 1.5 mm or greater and 2.5 mm or less.

[0173] The center thickness of each lens can satisfy any one of the following conditions:

[0174] Condition 1: CT4, CT5, CT6, CT8 > CT1 > CT2, CT3, CT7

[0175] Condition 2: CT1, CT4, CT5, CT6, CT8 > CT2 > CT3, CT7

[0176] Condition 3: CT1, CT2, CT4, CT5, CT6, CT8 > CT3 > CT7

[0177] Condition 4: CT5, CT6, CT8 > CT4 > CT1, CT2, CT3, CT7

[0178] Condition 5: CT6 > CT5 > CT1, CT2, CT3, CT4, CT7, CT8

[0179] Condition 6: CT6 > CT1, CT2, CT3, CT4, CT5, CT7, CT8

[0180] Condition 7: CT1, CT2, CT3, CT4, CT5, CT6, CT8 > CT7

[0181] Condition 8: CT5, CT6 > CT8 > CT1, CT2, CT3, CT4, CT7

[0182] When describing the center gap (CG) between lenses, the center gap (CG1) between the first lens (101) and the second lens (102) may be the largest, and at least one of the center gap (CG4) between the fourth lens and the fifth lens (104, 105) and the center gap (CG6) between the sixth lens and the seventh lens (106, 107) may be the smallest. The difference between the largest and smallest center gaps among the spaced lens gaps may be 2 mm or greater, for example, in the range of 2.5 mm to 3.5 mm.

[0183] The center gap between each lens can meet the following conditions.

[0184] Condition 1: CG1 > CG2, CG3, CG4, CG5, CG6, CG7

[0185] Condition 2: CG1, CG3, CG5, CG7 > CG2 > CG4, CG6

[0186] Condition 3: CG1 > CG3 > CG2, CG4, CG5, CG6, CG7

[0187] Condition 4: CG1, CG2, CG3, CG5, CG7 > CG4 = CG6

[0188] Condition 5: CG1, CG3 > CG5 > CG2, CG4, CG6, CG7

[0189] Condition 6: CG1, CG3, CG5 > CG7 > CG2, CG4, CG6

[0190] To illustrate the effective diameter, the lens having the maximum effective diameter can be a glass lens. The lens having the maximum effective diameter can be the first lens (101). Here, the effective diameter is the average of the effective diameter on the object side and the effective diameter on the sensor side of each lens. The lens surface having the maximum effective diameter can be the first surface (S1) of the first lens (101).

[0191] The lens with the smallest effective diameter can be a lens disposed between the first lens (101) and the aperture (STOP). The lens with the smallest effective diameter can be a fifth lens (105). The lens surface with the smallest effective diameter can be the ninth surface (S9) of the fifth lens (105). The effective diameter of a lens made of plastic can be smaller than that of a lens made of glass. The lens made of plastic can be disposed adjacent to the image sensor.

[0192] The effective diameter of each lens can satisfy any of the following conditions.

[0193] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0194] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0195] Condition 3: CA_L1, CA_L2 > CA_L3 > CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0196] Condition 4: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L5

[0197] Condition 5: CA_L1, CA_L2, CA_L3, CA_L4, CA_L6, CA_L7, CA_L8 > CA_L5

[0198] Condition 6: CA_L1, CA_L2, CA_L3, CA_L8 > CA_L6 > CA_L4, CA_L5, CA_L7

[0199] Condition 7: CA_L1, CA_L2, CA_L3, CA_L6, CA_L8 > CA_L7 > CA_L4, CA_L5

[0200] Condition 8: CA_L1, CA_L2, CA_L3 > CA_L8 > CA_L4, CA_L5, CA_L6, CA_L7

[0201] To illustrate the refractive index, the refractive index of the second lens (102) can be the largest among the lenses and can be greater than 1.75, for example, greater than 1.8. Any or all of the third lens (103), sixth lens (106), and eighth lens (108) can have the smallest refractive index among the lenses. For example, the refractive index of the third lens (103), sixth lens (106), and eighth lens (108) can be the smallest among the lenses and can be less than 1.6, for example, less than 1.55. The difference between the maximum and minimum refractive index can be 0.2 or greater. By setting the lens near the object as a high-refractive-index lens and setting the lens adjacent to the glass lens and the lens adjacent to the image sensor (500) as low-refractive-index lenses made of plastic material, the incident efficiency can be improved, and the refractive force between the glass lens and the plastic lens can be adjusted to guide light to the image sensor (500).

[0202] The refractive index of each lens can satisfy any of the following conditions.

[0203] Condition 1: n1 = n5 > n2, n3, n4, n6, n7, n8

[0204] Condition 2: n2 > n1, n3, n4, n5, n6, n7, n8

[0205] Condition 3: n1, n2, n4, n5, n7 > n3 = n6 = n8

[0206] Condition 4: n2 > n4 = n7 > n1, n3, n5, n6, n8

[0207] To compare Abbe numbers, at least one of the first lens (101) and the fifth lens (105) has the largest Abbe number among the lenses, and may be 60 or greater. At least one of the fourth lens (104) and the seventh lens (107) has the smallest Abbe number 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 greater. By setting the Abbe number of the fifth lens (105), which is located at the center of the optical system (1000), to the maximum, and setting the Abbe number of the seventh lens (107), which has a low refractive index and is adjacent to the image sensor (500), to the minimum, the dispersion of light traveling between the glass lenses and the plastic lenses can be controlled, and the dispersion between the glass lenses and the plastic lenses can be increased to guide light to the image sensor (500).

[0208] The Abbe number of each lens can satisfy any of the following conditions.

[0209] Condition 1: v1 = v5 > v2, v3, v4, v6, v7, v8

[0210] Condition 2: v1, v3, v5, v6, v8 > v2 > v4, v7

[0211] Condition 3: v1, v5 > v3 = v6 = v8 > v2, v4, v7

[0212] Condition 4: v1, v2, v3, v5, v6, v8 > v4 = v7

[0213] The focal lengths (F1, F3, F4, F7) of the first, third, fourth, and seventh lenses (101, 103, 104, 107) can have a negative (-) sign. The first, third, fourth, and seventh lenses (101, 103, 104, 107) can have a negative (-) refractive power. The focal lengths (F2, F5, F6, F8) of the second, fifth, sixth, and eighth lenses (102, 105, 106, 108) can have a positive (+) sign. The second, fifth, sixth, and eighth lenses (102, 105, 106, 108) can have a positive (+) refractive power.

[0214] Furthermore, the seventh lens (107) and the eighth lens (108), which are arranged adjacent to each other, can satisfy the following conditions.

[0215] Condition 1: The refractive index of a lens with positive refractive power < the refractive index of a lens with negative refractive power.

[0216] Condition 2: The dispersion value of a lens with positive refractive power is greater than the dispersion value of a lens with negative refractive power.

[0217] Here, in the plastic lens, the eighth lens (108) has a positive refractive power, and the seventh lens (107) has a negative refractive power, such that, according to conditions 1 and 2, the refractive index of the eighth lens (108) is less than that of the seventh lens (107), and the dispersion value of the eighth lens (108) is greater than that of the seventh lens (107). The chromatic aberration appearing in the plastic lens can be corrected by the plastic lens. In addition, since the seventh lens (107) and the eighth lens (108), which are plastic lenses arranged successively, satisfy the condition that the difference in refractive index is 0.1 or greater and 0.15 or less, and the difference in Abbe number is 20 or greater and 50 or less, the chromatic aberration appearing in the plastic lens can be compensated by the plastic lens.

[0218] Optical systems generate chromatic aberration, which is corrected by using cemented lenses or two lenses arranged sequentially. As the temperature changes from low to high, the lenses repeatedly contract and expand. Since lenses made of the same material exhibit the same amount of change in lens properties due to temperature variations, correcting chromatic aberration between lenses made of the same material is effective even when the temperature changes. Therefore, in the first embodiment of the present invention, chromatic aberration occurring in plastic lenses can be corrected by using a seventh lens (107) and an eighth lens (108).

[0219] When comparing focal lengths in absolute terms, the fourth lens (104) has the largest focal length among the lenses, and it can be 55 or greater and 65 or less. The sixth lens (106) has the smallest focal length among the lenses, and the absolute value of the focal length of the sixth lens (106) can be 7 or greater and 9 or less.

[0220] The absolute value of the focal length of each lens can satisfy any of the following conditions.

[0221] Condition 1: |f2|, |f4| > |f1| > |f3|, |f5|, |f6|, |f7|, |f8|

[0222] Condition 2: |f4| > |f2| > |f1|, |f3|, |f5|, |f6|, |f7|, |f8|

[0223] Condition 3: |f1|, |f2|, |f4|, |f5|, |f8| > |f3| > |f6|, |f7|

[0224] Condition 4: |f4| > |f1|, |f2|, |f3|, |f5|, |f6|, |f7|, |f8|

[0225] Condition 5: |f1|, |f2|, |f4|, |f8| > |f5| > |f3|, |f6|, |f7|

[0226] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5|, |f7|, |f8| > |f6|

[0227] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f8| > |f7| > |f6|

[0228] Condition 8: |f1|, |f2|, |f4| > |f8| > |f3|, |f5|, |f6|, |f7|

[0229] The thickness (T1) of the first lens (101) can have a difference of 1.3 times or more between the maximum and minimum thickness, for example, in the range of 1.3 times to 1.8 times, and the center thickness (CT1) can be the minimum and the edge thickness (ET1) can be the maximum. The thickness (T2) of the second lens (102) can be the maximum thickness in the range of 1 to 1.5 times the minimum thickness. The second lens (102) can have a center thickness (CT2) as the maximum and an edge thickness (ET2) as the minimum. The thickness (T3) of the third lens (103) can be the minimum at the center and the maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (104) can be the minimum at the center and the maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (105) can be at its maximum at the center and at its minimum at the edge, with the maximum thickness ranging from 1.3 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (106) can be at its maximum at the center and at its minimum at the edge, with the maximum thickness ranging from 2 to 2.5 times the minimum thickness. The thickness (T7) of the seventh lens (107) can be at its minimum at the center and at its maximum at the edge, with the maximum thickness ranging from 1.5 to 2 times the minimum thickness. The thickness (T8) of the eighth lens (108) can be at its maximum at the center and at its minimum at the edge, with the maximum thickness ranging from 1.5 to 2 times the minimum thickness.

[0230] The ratio of the center thickness to the edge thickness of each lens can be called the thickness ratio. When the ratio of the larger to the smaller center thickness to the smaller edge thickness satisfies 2 to 2.5, the lens is easy to manufacture and can be advantageous in terms of yield.

[0231] The thickness of each lens can satisfy any of the following conditions.

[0232] Condition 1: 0.5 < CT1 / ET1 < 1, 1.3 < ET1 / CT1 < 1.8

[0233] Condition 2: 1 < CT2 / ET2 < 1.5, 0.5 < ET2 / CT2 < 1

[0234] Condition 3: 0.3 < CT3 / ET3 < 0.7, 1.5 < ET3 / CT3 < 2

[0235] Condition 4: 0.5 < CT4 / ET4 < 1, 1 < ET4 / CT4 < 1.5

[0236] Condition 5: 1.3 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0237] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0238] Condition 7: 0.3 < CT7 / ET7 < 0.7, 1.5 < ET7 / CT7 < 2

[0239] Condition 8: 1.5 < CT8 / ET8 < 2, 0.5 < ET8 / CT8 < 1

[0240] Condition 9: 1 < ΣCT / ΣET < 1.2, 0.5 < ΣET / ΣCT < 1

[0241] Among the gaps (G1 to G7) between the lenses, the first gap (G1) between the first lens and the second lens (101, 102) can have a maximum value in the center and a minimum value in the edge. The second gap (G2) between the second lens and the third lens (102, 103) can have a minimum value in the center and a maximum value in the edge. The third gap (G3) between the third lens and the fourth lens (103, 104) can have a minimum value in the edge and a maximum value in the center. The fourth gap (G4) between the fourth lens and the fifth lens (104, 105) can have a minimum value in the center and a maximum value in the edge. The fifth gap (G5) between the fifth lens and the sixth lens (105, 106) can have a minimum value in the center and a maximum value in the edge. The sixth gap (G6) between the sixth lens and the seventh lens (106, 107) can have a minimum value in the center and a maximum value in the edge. The seventh gap (G7) between the seventh lens and the eighth lens (107, 108) can be at its maximum value at the center and at its minimum value at the edge.

[0242] Figure 6 , Figure 8 and Figure 10 It is shown Figure 1 The graphs show the diffraction MTF (modulation transfer function) curves of the optical system at room temperature, low temperature, and high temperature, and also show the modulation ratio according to the spatial frequency. Figure 6 , Figure 8 and Figure 10 As shown, in the first embodiment of the present invention, the deviation of the MTF at low or high temperatures based on room temperature can be less than 10%, i.e., 7% or less.

[0243] Figure 7 , Figure 9 and Figure 11 It is shown Figure 1 The graphs show the aberration characteristics of the optical system at room temperature, low temperature, and high temperature. Figure 7 , Figure 9 and Figure 11 In the aberration curve diagram, spherical aberration (longitudinal spherical aberration), astigmatism curve, and distortion are measured from left to right. Figure 7 , Figure 9 and Figure 11 In the graph, the X-axis represents focal length (mm) and distortion rate (%), while the Y-axis represents image height. Additionally, the spherical aberration graph is for light in the wavelength bands of approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm, and the astigmatism and distortion graph is for light in the wavelength band of approximately 546 nm. Figure 7 , Figure 9 and Figure 11 In the aberration diagram, the closer the curves at room temperature, low temperature, and high temperature are to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1000) according to the first embodiment has measurements close to the Y-axis in almost all regions. That is, the optical system (1000) according to the first embodiment has improved resolution and good optical performance not only at the center of the field of view (FOV) but also at the edges. Here, low temperature is -20 degrees or lower, for example, in the range of -20 to -40 degrees; room temperature is in the range of 22 degrees ± 5 degrees or in the range of 18 to 27 degrees; and high temperature can be 85 degrees or higher, for example, in the range of 85 to 105 degrees. Therefore, it can be seen that... Figure 7 , Figure 9 and Figure 11 The decrease in brightness ratio (modulation) from low temperature to high temperature is less than 10%, for example 5% or less, or almost unchanged.

[0244] Table 3 compares the changes in optical properties such as EFL, BFL, F-number (F#), TTL, and field of view (FOV_H) of the optical system according to the second embodiment at room temperature, low temperature, and high temperature. It can be seen that the rate of change of optical properties at low temperature is 5% or less, for example, 3% or less, relative to room temperature.

[0245] Table 3

[0246]

[0247] Therefore, as shown in Table 3, it can be seen that the changes in optical properties (e.g., the rate of change of effective focal length (EFL), TTL, BFL, F-number, and field of view (FOV_H)) from low to high temperature are less than 10%, or less than 5%, for example, within the range of 0% to 5%. This allows for the design of temperature compensation for plastic lenses, even when using at least one or two or more plastic lenses, thereby preventing a decrease in the reliability of optical properties.

[0248] The optical system of the second embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center part of the field of view (FOV) but also at the edge part.

[0249] In the following description, the configuration of an optical system according to a second embodiment of the present invention will be described with reference to the accompanying drawings.

[0250] Figure 12 This is a cross-sectional side view of the optical system according to the second embodiment and the camera device module including the optical system; Figure 13 This is a table showing the aspherical coefficient values ​​and conic constant (k) of each lens surface in the optical system according to the second embodiment; Figure 14 This is a table showing the thickness of each lens and the spacing between adjacent lenses in the optical system according to the second embodiment; Figure 15 This is a table showing the sag values ​​of each lens surface in the optical system according to the second embodiment; Figure 16 This is a table showing the tilt angle values ​​of each lens surface in the optical system according to the second embodiment; Figure 17 It is a graph showing the diffraction MTF (modulation transfer function) data of the optical system according to the second embodiment at room temperature; Figure 18 It is a graph showing data on the aberration characteristics of the optical system according to the second embodiment at room temperature; Figure 19 It is a graph showing the diffraction MTF data of the optical system according to the second embodiment at low temperature; Figure 20 It is a graph showing the aberration characteristics of the optical system according to the second embodiment at low temperature; Figure 21 This is a graph showing the diffraction MTF data of the optical system according to the second embodiment at high temperature; and Figure 22 It is a graph showing the aberration characteristics of the optical system according to the second embodiment at high temperatures.

[0251] The optical system according to the second embodiment includes a lens unit, and the lens unit may include a first lens (201) to an eighth lens (208). The first lens to the eighth lens (201, 202, 203, 204, 205, 206, 207, 208) may be arranged sequentially along the optical axis (OA). Light corresponding to information about the object may pass through the first lens (201) to the eighth lens (208) and the filter (500) and be incident on the image sensor (400).

[0252] The lens units can be arranged in sequence from the object side to the image side as the first lens (201), the second lens (202), the third lens (203), the fourth lens (204), the fifth lens (205), the aperture (STOP), the sixth lens (206), the seventh lens (207), and the eighth lens (208).

[0253] In another embodiment, one or more of another lens, plate, and optical component may be added between the first lens (201) and the eighth lens (208). Furthermore, one or more of another lens, plate, and optical component may be added in front of the first lens (201) or behind the eighth lens (208). Additionally, one or more of another lens, plate, and optical component may be added between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter (500) may be a plate lens. The refractive power of the plate lens may be '0'. The refractive power of the plate lens may be absent. Furthermore, a filter layer may be set between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter layer may be coated to form a filter.

[0254] The first lens (201) can be positioned closest to the object side. The first lens (201) can be positioned furthest from the sensor side. The first lens (201) can have a negative (-) refractive power on the optical axis (OA). The first lens (201) can comprise a plastic material or a glass material, and can be made of, for example, glass. A first lens (201) made of glass can reduce changes in the center position and radius of curvature caused by temperature variations in the surrounding environment, and can protect the incident-side surface of the optical system (1000).

[0255] The first surface (S1) on the object side of the first lens (201) may be convex relative to the optical axis, and the second surface (S2) on the sensor side may be concave. The first lens (201) may have a meniscus shape convex toward the object side. The first lens (201) may be made of glass and may have a spherical surface. At least one or both of the first surface (S1) and the second surface (S2) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0256] The refractive index (n1) of the first lens (201) can satisfy the condition n1 > 1.6 or n1 > 1.61. This increases the radius of curvature of both the first and second lenses (201, 202) and facilitates lens manufacturing. If the refractive index (n1) of the first lens (201) is less than this condition, the lens surface must be formed with a sharp concave or convex shape to increase the refractive power of both lenses (201, 202). In this case, lens manufacturing is not easy, the defect rate of the lens increases, and it may lead to a decrease in yield.

[0257] The second lens (202) can be the second one from the object side. The second lens (202) can be the seventh one from the sensor side. The second lens (202) can be positioned between the first lens (201) and the third lens (203). The second lens (202) can have a positive (+) refractive power on the optical axis (OA). The second lens (202) can comprise plastic or glass material. For example, the second lens (202) can be made of glass molding material.

[0258] The object-side third surface (S3) of the second lens (202) may be convex relative to the optical axis (OA), and the sensor-side fourth surface (S4) may also be convex. The second lens (202) may have a convex shape on both sides. The second lens (202) may be made of a glass molding material and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspheric coefficients of the third and fourth surfaces (S3, S4) may be set to... Figure 13 S1 and S2 of L2 in the middle. At least one or both of the third surface (S3) and the fourth surface (S4) can be set to have no critical point from the end of the optical axis (OA) to the effective region.

[0259] The third lens (203) can be the third from the object side. The third lens (203) can be the sixth from the sensor side. The third lens (203) can be positioned between the second lens (202) and the fourth lens (204). The third lens (203) can have a negative (-) refractive power on the optical axis (OA). The third lens (203) can comprise plastic or glass material. For example, the third lens (203) can be made of plastic material.

[0260] The fifth surface (S5) of the third lens (203) on the object side can be convex relative to the optical axis, and the sixth surface (S6) on the sensor side can be concave. The third lens (203) can have a meniscus shape convex toward the object side. The third lens (203) can be made of plastic material and can be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) can be aspherical. The aspheric coefficients of the fifth surface and the sixth surface (S5, S6) can be set to... Figure 13 S5 and S6 of L3 in the middle.

[0261] The fifth surface (S5) of the third lens (203) may include a critical point from the optical axis (OA) to the end of the effective region. When the fifth surface (S5) has a critical point, it may be located in the range of 75% to 85%, preferably 80% to 83%, of the effective radius (r31) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in the range of 3.5 mm to 4 mm, preferably 3.7 mm to 3.8 mm, from the optical axis (OA). The sixth surface (S6) of the third lens (203) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0262] The fourth lens (204) may be the fourth from the object side. The fourth lens (204) may be the fifth from the sensor side. The fourth lens (204) may be positioned between the third lens (203) and the fifth lens (205). The fourth lens (204) may have a positive (+) or negative (-) refractive power along the optical axis (OA). The fourth lens (204) may have a negative (-) refractive power. The fourth lens (204) may comprise plastic or glass material. For example, the fourth lens (204) may be made of plastic material.

[0263] Relative to the optical axis, the seventh surface (S7) of the fourth lens (204) on the object side can be convex, and the eighth surface (S8) on the sensor side can be concave. The fourth lens (204) can have a meniscus shape convex toward the object side. The fourth lens (204) can have a meniscus shape concave toward the sensor side. The fourth lens (204) can be made of plastic material and can be aspherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) can be aspherical. The aspheric coefficients of the seventh and eighth surfaces (S7, S8) can be set to... Figure 13 S1 and S2 of L4 in the middle. At least one or both of the seventh surface (S7) and the eighth surface (S8) can be set to have no critical point from the optical axis (OA) to the end of the effective region.

[0264] The fifth lens (205) can be configured as the fifth lens from the object side. The fifth lens (205) can also be configured as the fourth lens from the sensor side. The fifth lens (205) can be positioned between the fourth lens (204) and the sixth lens (206). The fifth lens (205) can have a positive (+) or negative (-) refractive power along the optical axis (OA). The fifth lens (205) can have a positive (+) refractive power. The fifth lens (205) can comprise plastic or glass material. For example, the fifth lens (205) can be made of glass material.

[0265] The ninth surface (S9) on the object-side fifth lens (205) may be convex relative to the optical axis (OA), and the tenth surface (S10) on the sensor-side may also be convex. The fifth lens (205) may have a shape with convex sides. The fifth lens (205) may be made of glass and may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0266] The aperture (STOP) can be set around the tenth surface (S10) on the sensor side of the fifth lens (205). The aperture (STOP) can be set around the eleventh surface (S11) on the object side of the sixth lens (206). The aperture can reduce the TTL within the field of view and can miniaturize the optical system. Therefore, it is possible to prevent the yield reduction of the optical system due to weight and to improve production efficiency. In addition, the optical system can be miniaturized by reducing the TTL within a horizontal field of view (FOV_H) of 100 to 130 degrees.

[0267] The sixth lens (206) can be configured as the sixth lens from the object side. The sixth lens (206) can also be configured as the third lens from the sensor side. The sixth lens (206) can be positioned between the fifth lens (205) and the seventh lens (207). The sixth lens (206) can have a positive (+) or negative (-) refractive power along the optical axis (OA). The sixth lens (206) can have a positive (+) refractive power. The sixth lens (206) can comprise plastic or glass material. For example, the sixth lens (206) can be made of plastic material.

[0268] Relative to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (206) may be convex, and the sensor-side twelfth surface (S12) may be convex. The sixth lens (206) may have a convex shape on both sides. The sixth lens (206) may be made of plastic material and may be aspherical. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspheric coefficients of the eleventh and twelfth surfaces (S11, S12) may be set to... Figure 13 S1 and S2 of L6 in the middle. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) can be set to have no critical point from the end of the optical axis (OA) to the effective region.

[0269] The seventh lens (207) can be configured as the seventh lens from the object side. The seventh lens (207) can also be configured as the second lens from the sensor side. The seventh lens (207) can be positioned between the sixth lens (206) and the eighth lens (208). The seventh lens (207) can have a positive (+) or negative (-) refractive power along the optical axis (OA). The seventh lens (207) can have a negative (-) refractive power. The seventh lens (207) can comprise plastic or glass material. For example, the seventh lens (207) can be made of plastic material.

[0270] Relative to the optical axis (OA), the object-side thirteenth surface (S13) of the seventh lens (207) can be convex, and the sensor-side fourteenth surface (S14) can be concave. The seventh lens (207) can have a shape with concave sides. The seventh lens (207) can be made of plastic material and can be aspherical. At least one or both of the thirteenth surface (S13) and the fourteenth surface (S14) can be aspherical. The aspheric coefficients of the thirteenth and fourteenth surfaces (S13, S14) can be set to... Figure 13 S13 and S14 of L7 in the middle.

[0271] The eighth lens (208) can be positioned furthest from the object side. The eighth lens (208) can be positioned closest to the image sensor (500). The eighth lens (208) can have a positive (+) or negative (-) refractive power on the optical axis (OA). The eighth lens (208) can have a positive (+) refractive power. The eighth lens (208) can comprise plastic or glass material. For example, the eighth lens (208) can be made of plastic material.

[0272] Relative to the optical axis (OA), the object-side fifteenth surface (S15) of the eighth lens (208) may be convex, and the sensor-side sixteenth surface (S16) may also be convex. The eighth lens (208) may have a convex shape on both sides. At least one or both of the fifteenth surface (S15) and the sixteenth surface (S16) may be aspherical. The aspheric coefficients of the fifteenth and sixteenth surfaces (S15, S16) may be set to... Figure 13 S15 and S16 of L8 in the middle.

[0273] The eighth lens (208) can be the plastic lens closest to the image sensor (500). Furthermore, by arranging two or more plastic lenses adjacent to the image sensor (500), aberrations such as spherical aberration and chromatic aberration can be improved through the lens surfaces having aspherical surfaces, and the impact on resolution can be controlled. Moreover, by arranging plastic lenses adjacent to the image sensor (500), plastic lenses can be insensitive to assembly tolerances compared to glass lenses. In other words, insensitivity to assembly tolerances means that even if the assembly differs slightly from the design during assembly, the optical performance may not be significantly affected. Furthermore, by making the two lenses (207, 208) adjacent to the image sensor (500) plastic, the optical performance can be improved through the lens surfaces having aspherical surfaces, and aberration characteristics can be improved, for example, and resolution degradation can be prevented.

[0274] Table 4

[0275]

[0276] Table 4 shows the surface number (“surface”), radius of curvature (“radius”), center thickness of each lens or distance between lens surfaces (“thickness”), refractive index (“nd”), Abbe number (“vd”), effective radius (“semi-aperture”), and focal length (“focal length”) of the lens according to the second embodiment of the present invention. Here, the units for radius of curvature and thickness or distance may be mm.

[0277] Table 5

[0278]

[0279] Table 5 shows the characteristics of the optical system according to the second embodiment of the present invention.

[0280] TTL refers to the optical axis distance from the object-side vertex of the first lens (201) to the imaging surface; SD refers to the optical axis distance from the aperture (STOP) to the image-side surface of the eighth lens (208); TD refers to the optical axis distance from the object-side vertex of the first lens (201) to the image-side surface of the eighth lens (208); F refers to the total focal length; F_LG1 refers to the composite focal length of the first lens (201) to the fifth lens (205) in the object-side direction of the aperture (STOP); F_LG2 refers to the composite focal length of the sixth lens (206) to the eighth lens (208). The composite focal length of the lens (208) in the image-side direction of the aperture (STOP), Fno refers to the ratio of the focal length of the lens to the effective diameter, ImgH refers to the distance from the optical axis (OA) to the diagonal end of the image sensor (400) or 1 / 2 of the maximum diagonal length, FOV_H refers to the horizontal field of view of the optical system, EPD refers to the diameter of the entrance pupil (effective aperture), BFL refers to the optical axis distance from the image-side surface of the eighth lens (108) to the imaging surface, and ET1 to ET8 refer to the thickness of the edge region of each lens.

[0281] The center thicknesses of the first to eighth lenses (201 to 208) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, the center gaps between two adjacent lenses are represented by CG1 to CG7, and the edge gaps between the edges of each lens are represented by EG1 to EG7. BFL (back focal length) is the optical axis distance from the image sensor (500) to the center of the last lens. 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 (500).

[0282] like Figure 12 As shown, in the lens unit of the second embodiment, the lens surfaces of the second, third, fourth, sixth, seventh, and eighth lenses (202, 203, 204, 206, 207, 208) may include aspherical surfaces with a 30th-order aspherical surface coefficient. For example, the second, third, fourth, sixth, seventh, and eighth lenses (202, 203, 204, 206, 207, 208) may include lens surfaces with a 30th-order aspherical surface coefficient. As described above, an aspherical surface with a 30th-order aspherical surface coefficient (non-zero value) can significantly alter the aspherical shape of the edge portion, and therefore, can effectively correct the optical performance of the edge portion of the field of view (FOV).

[0283] The thicknesses (T1 to T8) of the first to eighth lenses (201 to 208) and the gaps (G1 to G7) between adjacent lenses can be set. For example... Figure 14 As shown, the thickness of each lens in the Y-axis direction can be expressed in 0.1 mm or 0.2 mm or greater (T1 to T8), and the gap between each lens can be expressed in 0.1 mm or 0.2 mm or greater (G1 to G7).

[0284] When comparing the absolute values ​​of the radii of curvature of each lens, the radius of curvature of the fourth surface (S4) of the second lens (202) on the optical axis (OA) can be the largest among the lenses, and the radius of curvature of the sixth surface (S6) of the third lens (203) can be the smallest among the lenses. The difference between the maximum and minimum radii of curvature can be 150 times or greater, for example, in the range of 160 to 180 times.

[0285] Because the effective diameter of a plastic lens is smaller than that of a glass lens, a lens positioned on the object side of a plastic lens can have a strong refractive force to refract light through the plastic lens. Furthermore, the radius of curvature of the lens surface can be very small to enhance the refractive force.

[0286] The absolute value of the radius of curvature of the first surface (S1) of the first lens (201) can be greater than the absolute value of the radius of curvature of the second surface (S2). The absolute value of the radius of curvature of the third surface (S3) of the second lens (202) can be less than the absolute value of the radius of curvature of the fourth surface (S4). The absolute value of the radius of curvature of the fifth surface (S5) of the third lens (203) can be greater than the absolute value of the radius of curvature of the sixth surface (S6). The absolute value of the radius of curvature of the seventh surface (S7) of the fourth lens (204) can be greater than the absolute value of the radius of curvature of the eighth surface (S8). The absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (205) can be greater than the absolute value of the radius of curvature of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (206) can be less than the absolute value of the radius of curvature of the twelfth surface (S12). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (207) can be greater than the absolute value of the radius of curvature of the fourteenth surface (S14). The absolute value of the radius of curvature of the fifteenth surface (S15) of the eighth lens (108) can be less than the absolute value of the radius of curvature of the sixteenth surface (S16).

[0287] The ratio of the radii of curvature of each lens can satisfy the following condition.

[0288] Condition 1: 5 < |L1R1 / L1R2| < 6

[0289] Condition 2: 0.1 < |L2R1 / L2R2| < 0.5

[0290] Condition 3: 1 < |L3R1 / L3R2| < 2

[0291] Condition 4: 1 < L4R1 / L4R2 < 2

[0292] Condition 5: 1 < |L5R1 / L5R2| < 2

[0293] Condition 6: 0.5 < |L6R1 / L6R2| < 1

[0294] Condition 7: 20 < |L7R1 / L7R2| < 25

[0295] Condition 8: 0.1 < |L8R1 / L8R2| < 0.5

[0296] When the center thickness (CT) of a lens is described based on the optical axis, the center thickness (CT5) of the fifth lens (205) is the largest among the lenses, and the center thickness (CT7) of the seventh lens (207) is the smallest among the lenses. The difference between the maximum and minimum center thicknesses in a lens can be in the range of 1.5 mm or greater and 2.5 mm or less.

[0297] The center thickness of each lens can satisfy any one of the following conditions:

[0298] Condition 1: CT2, CT4, CT5, CT6, CT8 > CT1 > CT3, CT7

[0299] Condition 2: CT4, CT5, CT6, CT8 > CT2 > CT1, CT3, CT7

[0300] Condition 3: CT1, CT2, CT4, CT5, CT6, CT8 > CT3 > CT7

[0301] Condition 4: CT5, CT6, CT8 > CT4 > CT1, CT2, CT3, CT7

[0302] Condition 5: CT5 > CT1, CT2, CT3, CT4, CT6, CT7, CT8

[0303] Condition 6: CT5, CT8 > CT6 > CT1, CT2, CT3, CT4, CT7

[0304] Condition 7: CT1, CT2, CT3, CT4, CT5, CT6, CT8 > CT7

[0305] Condition 8: CT6 > CT8 > CT1, CT2, CT3, CT4, CT5, CT7

[0306] To illustrate the inter-lens center gap (CG), the center gap (CG3) between the third lens (203) and the fourth lens (204) can be the maximum value, and at least one of the center gaps (CG4) between the fourth lens and the fifth lens (204, 205) and the center gaps (CG6) between the sixth lens and the seventh lens (206, 207) can be the minimum value. The difference between the maximum and minimum center gaps among the spaced lens gaps can be 2 mm or greater, for example, in the range of 2.5 mm to 3.5 mm.

[0307] The center gap between each lens can meet the following conditions.

[0308] Condition 1: CG3, CG7 > CG1 > CG2, CG4, CG5, CG6

[0309] Condition 2: CG1, CG3, CG7 > CG2 > CG4, CG5, CG6

[0310] Condition 3: CG3 > CG1, CG2, CG4, CG5, CG6, CG7

[0311] Condition 4: CG1, CG2, CG3, CG5, CG7 > CG4 = CG6

[0312] Condition 5: CG1, CG2, CG3, CG7 > CG5 > CG4, CG6

[0313] Condition 6: CG3 > CG7 > CG1, CG2, CG4, CG5, CG6

[0314] To illustrate the effective diameter, the lens having the maximum effective diameter can be a glass lens. The lens having the maximum effective diameter can be the first lens (201). Here, the effective diameter is the average of the effective diameter on the object side and the effective diameter on the sensor side of each lens. The lens surface having the maximum effective diameter can be the first surface (S1) of the first lens (201).

[0315] The lens with the smallest effective diameter can be a lens disposed between the first lens (201) and the aperture (STOP). The lens with the smallest effective diameter can be a fifth lens (205). The lens surface with the smallest effective diameter can be the ninth surface (S9) of the fifth lens (205). The effective diameter of a lens made of plastic can be smaller than that of a lens made of glass. The lens made of plastic can be disposed adjacent to the image sensor.

[0316] The effective diameter of each lens can satisfy any of the following conditions.

[0317] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0318] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0319] Condition 3: CA_L1, CA_L2, CA_L8 > CA_L3 > CA_L4, CA_L5, CA_L6, CA_L7

[0320] Condition 4: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L5

[0321] Condition 5: CA_L1, CA_L2, CA_L3, CA_L4, CA_L6, CA_L7, CA_L8 > CA_L5

[0322] Condition 6: CA_L1, CA_L2, CA_L3, CA_L8 > CA_L6 > CA_L4, CA_L5, CA_L7

[0323] Condition 7: CA_L1, CA_L2, CA_L3, CA_L6, CA_L8 > CA_L7 > CA_L4, CA_L5

[0324] Condition 8: CA_L1, CA_L2 > CA_L8 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0325] To illustrate the refractive index, the refractive index of the second lens (202) can be the largest among the lenses and can be greater than 1.75, for example, greater than 1.8. Any or all of the third lens (203), sixth lens (206), and eighth lens (208) can have the smallest refractive index among the lenses. For example, the refractive index of the third lens (203), sixth lens (206), and eighth lens (208) can be the smallest among the lenses and can be less than 1.6, for example, less than 1.55. The difference between the maximum and minimum refractive index can be 0.2 or greater. By setting the lens near the object as a high-refractive-index lens and setting the lens adjacent to the glass lens and the lens adjacent to the image sensor (500) as low-refractive-index lenses made of plastic material, the incident efficiency can be improved, and the refractive force between the glass lens and the plastic lens can be adjusted to guide light to the image sensor (500).

[0326] The refractive index of each lens can satisfy any of the following conditions.

[0327] Condition 1: n1 = n5 > n2, n3, n4, n6, n7, n8

[0328] Condition 2: n2 > n1, n3, n4, n5, n6, n7, n8

[0329] Condition 3: n1, n2, n4, n5, n7 > n3 = n6 = n8

[0330] Condition 4: n2 > n4 = n7 > n1, n3, n5, n6, n8

[0331] To compare Abbe numbers, at least one of the first lens (201) and the fifth lens (205) has the largest Abbe number among the lenses, and may be 60 or greater. At least one of the fourth lens (204) and the seventh lens (207) has the smallest Abbe number 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 greater. By setting the Abbe number of the fifth lens (205) located at the center of the optical system (1100) to the maximum and setting the Abbe number of the seventh lens (207) with a low refractive index adjacent to the image sensor (500) to the minimum, the dispersion of light traveling between the glass lenses and the plastic lenses can be controlled, and the dispersion between the glass lenses and the plastic lenses can be increased to guide light to the image sensor (500).

[0332] The Abbe number of each lens can satisfy any of the following conditions.

[0333] Condition 1: v1 = v5 > v2, v3, v4, v6, v7, v8

[0334] Condition 2: v1, v3, v5, v6, v8 > v2 > v4, v7

[0335] Condition 3: v1, v5 > v3 = v6 = v8 > v2, v4, v7

[0336] Condition 4: v1, v2, v3, v5, v6, v8 > v4 = v7

[0337] The focal lengths (F1, F3, F4, F7) of the first, third, fourth, and seventh lenses (201, 203, 204, 207) can have a negative (-) sign. The first, third, fourth, and seventh lenses (201, 203, 204, 207) can have a negative (-) refractive power. The focal lengths (F2, F5, F6, F8) of the second, fifth, sixth, and eighth lenses (202, 205, 206, 208) can have a positive (+) sign. The second, fifth, sixth, and eighth lenses (202, 205, 206, 208) can have a positive (+) refractive power.

[0338] In addition, the seventh lens (207) and the eighth lens (208), which are arranged adjacent to each other, can satisfy the following conditions.

[0339] Condition 1: The refractive index of a lens with positive refractive power < the refractive index of a lens with negative refractive power.

[0340] Condition 2: The dispersion value of a lens with positive refractive power is greater than the dispersion value of a lens with negative refractive power.

[0341] Here, in the plastic lens, the eighth lens (208) has a positive refractive power, and the seventh lens (207) has a negative refractive power, such that, according to conditions 1 and 2, the refractive index of the eighth lens (208) is less than that of the seventh lens (207), and the dispersion value of the eighth lens (208) is greater than that of the seventh lens (207). The chromatic aberration appearing in the plastic lens can be corrected by the plastic lens. In addition, since the seventh lens (207) and the eighth lens (208), which are plastic lenses arranged successively, satisfy the condition that the difference in refractive index is 0.1 or greater and 0.15 or less, and the difference in Abbe number is 20 or greater and 50 or less, the chromatic aberration appearing in the plastic lens can be compensated by the plastic lens.

[0342] Optical systems generate chromatic aberration, which is corrected by using cemented lenses or two lenses arranged sequentially. As the temperature changes from low to high, the lenses repeatedly contract and expand. Since lenses made of the same material exhibit the same amount of change in lens properties due to temperature variations, correcting chromatic aberration between lenses made of the same material is effective even when the temperature changes. Therefore, in the second embodiment of the invention, chromatic aberration occurring in plastic lenses can be corrected by using a seventh lens (207) and an eighth lens (208).

[0343] When comparing focal lengths in absolute terms, the fourth lens (204) has the largest focal length among the lenses, and it can be 55 or greater and 65 or less. The sixth lens (206) has the smallest focal length among the lenses, and the absolute value of the focal length of the sixth lens (206) can be 7 or greater and 9 or less.

[0344] The absolute value of the focal length of each lens can satisfy any of the following conditions.

[0345] Condition 1: |f2|, |f4| > |f1| > |f3|, |f5|, |f6|, |f7|, |f8|

[0346] Condition 2: |f4| > |f2| > |f1|, |f3|, |f5|, |f6|, |f7|, |f8|

[0347] Condition 3: |f1|, |f2|, |f4|, |f8| > |f3| > |f5|, |f6|, |f7|

[0348] Condition 4: |f4| > |f1|, |f2|, |f3|, |f5|, |f6|, |f7|, |f8|

[0349] Condition 5: |f1|, |f2|, |f3|, |f4|, |f8| > |f5| > |f6|, |f7|

[0350] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5|, |f7|, |f8| > |f6|

[0351] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f8| > |f7| > |f6|

[0352] Condition 8: |f1|, |f2|, |f4| > |f8| > |f3|, |f5|, |f6|, |f7|

[0353] The thickness (T1) of the first lens (201) can have a difference of 1.3 times or more between the maximum and minimum thickness, for example, in the range of 1.3 times to 1.8 times, and the center thickness (CT1) can be the minimum and the edge thickness (ET1) can be the maximum. The thickness (T2) of the second lens (202) can be the maximum thickness in the range of 1 to 1.5 times the minimum thickness. The second lens (202) can have a center thickness (CT2) as the maximum and an edge thickness (ET2) as the minimum. The thickness (T3) of the third lens (203) can be the minimum at the center and the maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (104) can be the minimum at the center and the maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (205) can be at its maximum at the center and at its minimum at the edge, with the maximum thickness ranging from 1.3 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (206) can be at its maximum at the center and at its minimum at the edge, with the maximum thickness ranging from 2 to 2.5 times the minimum thickness. The thickness (T7) of the seventh lens (207) can be at its minimum at the center and at its maximum at the edge, with the maximum thickness ranging from 1.5 to 2 times the minimum thickness. The thickness (T8) of the eighth lens (208) can be at its maximum at the center and at its minimum at the edge, with the maximum thickness ranging from 1.5 to 2 times the minimum thickness.

[0354] The ratio of the center thickness to the edge thickness of each lens can be called the thickness ratio. When the ratio of the larger to the smaller center thickness to the smaller edge thickness satisfies 2 to 2.5, the lens is easy to manufacture and can be advantageous in terms of yield.

[0355] The thickness of each lens can satisfy any of the following conditions.

[0356] Condition 1: 0.3 < CT1 / ET1 < 0.7, 2 < ET1 / CT1 < 2.5

[0357] Condition 2: 1.5 < CT2 / ET2 < 2, 0.3 < ET2 / CT2 < 0.7

[0358] Condition 3: 0.3 < CT3 / ET3 < 0.7, 1.5 < ET3 / CT3 < 2

[0359] Condition 4: 0.8 < CT4 / ET4 < 1.2, 0.5 < ET4 / CT4 < 1

[0360] Condition 5: 1.2 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0361] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0362] Condition 7: 0.3 < CT7 / ET7 < 0.7, 1.5 < ET7 / CT7 < 2

[0363] Condition 8: 2 < CT8 / ET8 < 2.5, 0.1 < ET8 / CT8 < 0.5

[0364] Condition 9: 1 < ΣCT / ΣET < 1.2, 0.5 < ΣET / ΣCT < 1

[0365] Among the gaps (G1 to G7) between the lenses, the first gap (G1) between the first lens and the second lens (201, 202) can have a maximum value at the center and a minimum value at the edge. The second gap (G2) between the second lens and the third lens (202, 203) can have a minimum value at the center and a maximum value at the edge. The third gap (G3) between the third lens and the fourth lens (203, 204) can have a minimum value at the edge and a maximum value at the center. The fourth gap (G4) between the fourth lens and the fifth lens (204, 205) can have a minimum value at the center and a maximum value at the edge. The fifth gap (G5) between the fifth lens and the sixth lens (205, 206) can have a minimum value at the center and a maximum value at the edge. The sixth gap (G6) between the sixth lens and the seventh lens (206, 207) can have a minimum value at the center and a maximum value at the edge. The seventh gap (G7) between the seventh lens and the eighth lens (207, 208) can be at its maximum value at the center and at its minimum value at the edge.

[0366] Figure 17 , Figure 19 and Figure 21 It is shown Figure 12 The graphs show the diffraction MTF (modulation transfer function) curves of the optical system at room temperature, low temperature, and high temperature, and also show the modulation ratio according to the spatial frequency. Figure 17 , Figure 19 and Figure 21 As shown, in the second embodiment of the present invention, the deviation of the MTF at low or high temperatures based on room temperature can be less than 10%, i.e., 7% or less.

[0367] Figure 18 , Figure 20 and Figure 22 It is shown Figure 12 The graphs show the aberration characteristics of the optical system at room temperature, low temperature, and high temperature. Figure 18 , Figure 20 and Figure 22 In the aberration curve diagram, spherical aberration (longitudinal spherical aberration), astigmatism curve, and distortion are measured from left to right. Figure 18 , Figure 20 and Figure 22 In the graph, the X-axis represents focal length (mm) and distortion rate (%), while the Y-axis represents image height. Additionally, the spherical aberration graph is for light in the wavelength bands of approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm, and the astigmatism and distortion graph is for light in the wavelength band of approximately 546 nm. Figure 18 , Figure 20 and Figure 22 In the aberration diagram, the closer the curves at room temperature, low temperature, and high temperature are to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1100) according to the second embodiment has measurements close to the Y-axis in almost all regions. That is, the optical system (1100) according to the second embodiment has improved resolution and good optical performance not only at the center of the field of view (FOV) but also at the edges. 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 in the range of 18 to 27 degrees; and the high temperature can be 85 degrees or higher, for example, in the range of 85 to 105 degrees. Therefore, it can be seen that... Figure 18 , Figure 20 and Figure 22 The decrease in brightness ratio (modulation) from low temperature to high temperature is less than 10%, for example 5% or less, or almost unchanged.

[0368] Table 6 compares the changes in optical properties such as EFL, BFL, F-number (F#), TTL, and field of view (FOV_H) of the optical system according to the second embodiment at room temperature, low temperature, and high temperature. It can be seen that the rate of change of optical properties at low temperature is 5% or less, for example 3% or less, relative to room temperature.

[0369] Table 6

[0370]

[0371] Therefore, as shown in Table 6, it can be seen that the rate of change of optical properties, such as effective focal length (EFL), TTL, BFL, F-number, and field of view (FOV_H), according to temperature changes from low to high temperatures is 10% or less, i.e., 5% or less, for example, in the range of 0% to 5%. This allows for the design of temperature compensation for plastic lenses, even when using one or two or more plastic lenses, thereby preventing a decrease in the reliability of optical properties.

[0372] The optical system of the first embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can also have good optical performance not only at the center part of the field of view (FOV) but also at the edge part.

[0373] In the following description, the configuration of an optical system according to a third embodiment of the present invention is described with reference to the accompanying drawings.

[0374] Figure 23 This is a cross-sectional side view of the optical system according to the third embodiment and the camera device module including the optical system; Figure 24 This is a table showing the aspherical coefficient values ​​and conic constant (k) of each lens surface in the optical system according to the third embodiment; Figure 25 This is a table showing the thickness of each lens and the spacing between adjacent lenses in an optical system according to the third embodiment; Figure 26 This is a table showing the sag values ​​of each lens surface in the optical system according to the third embodiment; Figure 27 This is a table showing the tilt angle values ​​of each lens surface in the optical system according to the third embodiment; Figure 28 It is a graph showing the diffraction MTF (modulation transfer function) data of the optical system according to the third embodiment at room temperature; Figure 29 It is a graph showing the aberration characteristics of the optical system according to the third embodiment at room temperature; Figure 30 It is a graph showing the diffraction MTF data of the optical system according to the third embodiment at low temperature; Figure 31 It is a graph showing the aberration characteristics of the optical system according to the third embodiment at low temperature; Figure 32 This is a graph showing the diffraction MTF data of the optical system according to the third embodiment at high temperature; and Figure 33 It is a graph showing the aberration characteristics of the optical system according to the third embodiment at high temperatures.

[0375] The optical system according to the third embodiment includes a lens unit, and the lens unit may include a first lens (301) to an eighth lens (308). The first lens to the eighth lens (301, 302, 303, 304, 305, 306, 307, 308) may be arranged sequentially along the optical axis (OA). Light corresponding to information about the object may pass through the first lens (301) to the eighth lens (308) and the filter (500) and be incident on the image sensor (400).

[0376] The lens units can be configured in sequence from the object side to the image side as a first lens (301), a second lens (302), a third lens (303), a fourth lens (304), a fifth lens (305), an aperture (STOP), a sixth lens (306), a seventh lens (307), and an eighth lens (308).

[0377] In another embodiment, one or more of another lens, plate, and optical components may be added between the first lens (301) and the eighth lens (308). Additionally, one or more of another lens, plate, and optical components may be added in front of the first lens (301) or behind the eighth lens (308). Furthermore, one or more of another lens, plate, and optical components may be added between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter (500) may be a plate lens. The refractive power of the plate lens may be '0'. The refractive power of the plate lens may be absent. Additionally, a filter layer may be disposed between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter layer may be coated to form a filter.

[0378] The first lens (301) can be positioned closest to the object side. The first lens (301) can also be positioned furthest from the sensor side. The first lens (301) can have a negative (-) refractive power along the optical axis (OA). The first lens (301) can comprise a plastic material or a glass material, and can be made of, for example, glass. A first lens (301) made of glass can reduce changes in its center position and radius of curvature due to temperature variations in the surrounding environment, and can protect the incident-side surface of the optical system (1000).

[0379] The first surface (S1) on the object side of the first lens (301) may be convex relative to the optical axis, and the second surface (S2) on the sensor side may be concave. The first lens (301) may have a meniscus shape convex toward the object side. The first lens (301) may be made of glass and may have a spherical surface. At least one or both of the first surface (S1) and the second surface (S2) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0380] The refractive index (n1) of the first lens (301) can satisfy the condition that n1 > 1.6 or n1 > 1.61. This can increase the radius of curvature of both the first and second lenses (301, 302) and facilitate lens manufacturing. If the refractive index (n1) of the first lens (301) is less than this condition, then in order to increase the refractive power of the first and second lenses (301, 302), the lens surface must be formed as sharply concave or convex. In this case, lens manufacturing is not easy, the defect rate of the lens increases, and it may lead to a decrease in yield.

[0381] The second lens (302) may be the second from the object side. The second lens (302) may be the seventh from the sensor side. The second lens (302) may be positioned between the first lens (301) and the third lens (303). The second lens (302) may have a positive (+) refractive power on the optical axis (OA). The second lens (302) may comprise a plastic or glass material. For example, the second lens (302) may be made of a glass molding material.

[0382] The object-side third surface (S3) of the second lens (302) may be convex relative to the optical axis (OA), and the sensor-side fourth surface (S4) may be concave. The second lens (302) may have a meniscus shape that is concave toward the sensor side. The second lens (302) may be made of a glass molding material and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The asphericity of the third surface and the fourth surface (S3, S4) may be set to... Figure 24 S1 and S2 of L2 in the middle. At least one or both of the third surface (S3) and the fourth surface (S4) can be set to have no critical point from the end of the optical axis (OA) to the effective region.

[0383] The third lens (303) may be the third from the object side. The third lens (303) may be the sixth from the sensor side. The third lens (303) may be positioned between the second lens (302) and the fourth lens (304). The third lens (303) may have a negative (-) refractive power on the optical axis (OA). The third lens (303) may comprise plastic or glass material. For example, the third lens (303) may be made of plastic material.

[0384] The fifth surface (S5) of the third lens (303) on the object side can be convex relative to the optical axis, and the sixth surface (S6) on the sensor side can be concave. The third lens (303) can have a meniscus shape convex toward the object side. The third lens (303) can be made of plastic material and can be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) can be aspherical. The aspheric coefficients of the fifth surface and the sixth surface (S5, S6) can be set to... Figure 24 S5 and S6 of L3 in the middle.

[0385] The fifth surface (S5) of the third lens (303) may include a critical point from the optical axis (OA) to the end of the effective region. When the fifth surface (S5) has a critical point, it may be located in the range of 80% to 90%, preferably 85% to 88%, of the effective radius (r31) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in the range of 4.0 mm to 4.5 mm, preferably 4.2 mm to 4.3 mm, from the optical axis (OA). The sixth surface (S6) of the third lens (303) may be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0386] The fourth lens (304) may be the fourth from the object side. The fourth lens (304) may be the fifth from the sensor side. The fourth lens (304) may be positioned between the third lens (303) and the fifth lens (305). The fourth lens (304) may have a positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (304) may have a negative (-) refractive power. The fourth lens (304) may comprise plastic or glass material. For example, the fourth lens (304) may be made of plastic material.

[0387] Relative to the optical axis, the seventh surface (S7) of the fourth lens (304) on the object side can be convex, and the eighth surface (S8) on the sensor side can be concave. The fourth lens (304) can have a meniscus shape convex toward the object side. The fourth lens (304) can have a meniscus shape concave toward the sensor side. The fourth lens (304) can be made of plastic material and can be aspherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) can be aspherical. The aspheric coefficients of the seventh and eighth surfaces (S7, S8) can be set to... Figure 24 S1 and S2 of L4 in the middle. At least one or both of the seventh surface (S7) and the eighth surface (S8) can be set to have no critical point from the optical axis (OA) to the end of the effective region.

[0388] The fifth lens (305) can be configured as the fifth lens from the object side. The fifth lens (305) can also be configured as the fourth lens from the sensor side. The fifth lens (305) can be positioned between the fourth lens (304) and the sixth lens (306). The fifth lens (305) can have a positive (+) or negative (-) refractive power along the optical axis (OA). The fifth lens (305) can have a positive (+) refractive power. The fifth lens (305) can comprise plastic or glass material. For example, the fifth lens (305) can be made of glass material.

[0389] The ninth surface (S9) on the object-side fifth lens (305) may be convex relative to the optical axis (OA), and the tenth surface (S10) on the sensor-side may also be convex. The fifth lens (305) may have a shape with convex sides. The fifth lens (305) may be made of glass and may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may also be configured to have no critical point from the optical axis (OA) to the end of the effective region.

[0390] The aperture (STOP) can be set around the tenth surface (S10) on the sensor side of the fifth lens (305). The aperture (STOP) can be set around the eleventh surface (S11) on the object side of the sixth lens (306). The aperture can reduce the TTL within the field of view and can miniaturize the optical system. Therefore, the efficiency reduction due to weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within a horizontal field of view (FOV_H) of 100 to 130 degrees.

[0391] The sixth lens (306) can be configured as the sixth lens from the object side. The sixth lens (306) can also be configured as the third lens from the sensor side. The sixth lens (306) can be positioned between the fifth lens (305) and the seventh lens (307). The sixth lens (306) can have a positive (+) or negative (-) refractive power along the optical axis (OA). The sixth lens (306) can have a positive (+) refractive power. The sixth lens (306) can comprise plastic or glass material. For example, the sixth lens (206) can be made of plastic material.

[0392] Relative to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (306) may be convex, and the sensor-side twelfth surface (S12) may also be convex. The sixth lens (306) may have a convex shape on both sides. The sixth lens (306) may be made of plastic material and may be aspherical. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspheric coefficients of the eleventh and twelfth surfaces (S11, S12) may be set to... Figure 24 S1 and S2 of L6 in the middle. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) can be set to have no critical point from the end of the optical axis (OA) to the effective region.

[0393] The seventh lens (307) can be configured as the seventh lens from the object side. The seventh lens (307) can also be configured as the second lens from the sensor side. The seventh lens (307) can be positioned between the sixth lens (306) and the eighth lens (308). The seventh lens (207) can have a positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (307) can have a negative (-) refractive power. The seventh lens (307) can comprise plastic or glass material. For example, the seventh lens (307) can be made of plastic material.

[0394] Relative to the optical axis (OA), the object-side thirteenth surface (S13) of the seventh lens (307) may be convex, and the sensor-side fourteenth surface (S14) may also be convex. The seventh lens (307) may have a shape with concave sides. The seventh lens (307) may be made of plastic material and may be aspherical. At least one or both of the thirteenth surface (S13) and the fourteenth surface (S14) may be aspherical. The aspheric coefficients of the thirteenth and fourteenth surfaces (S13, S14) may be set to... Figure 24 S13 and S14 of L7 in the middle.

[0395] The eighth lens (308) can be positioned furthest from the object side. The eighth lens (308) can be positioned closest to the image sensor (500). The eighth lens (308) can have a positive (+) or negative (-) refractive power on the optical axis (OA). The eighth lens (308) can have a positive (+) refractive power. The eighth lens (308) can comprise plastic or glass material. For example, the eighth lens (308) can be made of plastic material.

[0396] Relative to the optical axis (OA), the object-side fifteenth surface (S15) of the eighth lens (308) may be convex, and the sensor-side sixteenth surface (S16) may be concave. The eighth lens (308) may have a convex shape on both sides. At least one or both of the fifteenth surface (S15) and the sixteenth surface (S16) may be aspherical. The aspheric coefficients of the fifteenth and sixteenth surfaces (S15, S16) may be set to... Figure 24 S15 and S16 of L8 in the middle.

[0397] The eighth lens (308) can be the plastic lens closest to the image sensor (500). Furthermore, by arranging two or more plastic lenses adjacent to the image sensor (500), aberrations such as spherical aberration and chromatic aberration can be improved through the lens surface having an aspherical surface, and the impact on resolution can be controlled. Moreover, by arranging plastic lenses adjacent to the image sensor (500), plastic lenses are less sensitive to assembly tolerances compared to glass lenses. In other words, insensitivity to assembly tolerances means that even if the assembly differs slightly from the design during assembly, the optical performance may not be significantly affected. Furthermore, by making the two lenses (307, 308) adjacent to the image sensor (500) plastic, optical performance can be improved through the lens surface having an aspherical surface, and aberration characteristics can be improved, for example, and resolution degradation can be prevented.

[0398] Table 7

[0399]

[0400] Table 7 shows the surface number (“surface”), radius of curvature (“radius”), center thickness of each lens or distance between lens surfaces (“thickness”), refractive index (“nd”), Abbe number (“vd”), effective radius (“semi-aperture”), and focal length (“focal length”) of the lens according to the third embodiment of the present invention. Here, the units for radius of curvature and thickness or distance may be mm.

[0401] Table 8

[0402]

[0403] Table 8 shows the characteristics of the imaging lens according to the third embodiment of the present invention.

[0404] TTL refers to the optical axis distance from the object-side vertex of the first lens (301) to the upper surface; SD refers to the optical axis distance from the aperture (STOP) to the upper surface of the ninth lens (309); TD refers to the optical axis distance from the object-side vertex of the first lens (301) to the upper surface of the ninth lens (309); F refers to the total focal length; F_LG1 refers to the composite focal length of the first lens (301) to the third lens (303) in the object-side direction of the aperture (STOP); and F_LG2 refers to the total focal length of the fourth lens (304) to the ninth lens. (309) The compound focal length in the upward direction of the aperture (STOP), Fno refers to the ratio of the focal length of the lens to the effective diameter, ImgH refers to the distance from the optical axis (OA) to the diagonal end of the image sensor (400) or 1 / 2 of the maximum diagonal length, FOV_H refers to the horizontal viewing angle of the optical system, EPD refers to the diameter of the entrance pupil (effective aperture), BFL refers to the optical axis distance from the image side surface of the eighth lens (308) to the imaging surface, and ET1 to ET8 refer to the thickness of the edge region of each lens.

[0405] The center thickness of the first to eighth lenses (301 to 308) is represented by CT1 to CT8, the edge thickness of the effective area of ​​each lens is represented by ET1 to ET8, the center gap between two adjacent lenses is represented by CG1 to CG7, and the edge gap between the edges of each lens is represented by EG1 to EG7. BFL (back focal length) is the optical axis distance from the image sensor (500) to the center of the last lens. TTL is the optical axis distance from the center of the first surface (S1) of the first lens (301) to the upper surface of the image sensor (500).

[0406] like Figure 23 As shown, in the lens unit of the third embodiment, the lens surfaces of the second, third, fourth, sixth, seventh, and eighth lenses (302, 303, 304, 306, 307, 308) may include aspherical surfaces with a 30th-order aspherical surface coefficient. For example, the second, third, fourth, sixth, seventh, and eighth lenses (302, 303, 304, 306, 307, 308) may include lens surfaces with a 30th-order aspherical surface coefficient. As described above, an aspherical surface with a 30th-order aspherical surface coefficient (non-zero value) can significantly alter the aspherical shape of the edge portion, and therefore, can effectively correct the optical performance of the edge portion of the field of view (FOV).

[0407] The thicknesses (T1 to T8) of the first to eighth lenses (301 to 308) and the gaps (G1 to G7) between adjacent lenses can be set. For example... Figure 14 As shown, the thickness of each lens in the Y-axis direction can be expressed in 0.1 mm or 0.2 mm or greater (T1 to T8), and the gap between each lens can be expressed in 0.1 mm or 0.2 mm or greater (G1 to G7).

[0408] When comparing the absolute values ​​of the curvature radii of each lens, the curvature of the thirteenth surface (S13) of the seventh lens (307) on the optical axis (OA) can be the largest among the lenses, and the curvature of the sixth surface (S6) of the third lens (303) can be the smallest among the lenses.

[0409] Because the effective diameter of a plastic lens is smaller than that of a glass lens, a lens positioned on the object side of a plastic lens can have a strong refractive force to refract light through the plastic lens. Furthermore, the radius of curvature of the lens surface can be very small to enhance the refractive force.

[0410] The absolute value of the radius of curvature of the first surface (S1) of the first lens (301) can be greater than the absolute value of the radius of curvature of the second surface (S2). The absolute value of the radius of curvature of the third surface (S3) of the second lens (302) can be less than the absolute value of the radius of curvature of the fourth surface (S4). The absolute value of the radius of curvature of the fifth surface (S5) of the third lens (303) can be greater than the absolute value of the radius of curvature of the sixth surface (S6). The absolute value of the radius of curvature of the seventh surface (S7) of the fourth lens (304) can be greater than the absolute value of the radius of curvature of the eighth surface (S8). The absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (305) can be greater than the absolute value of the radius of curvature of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (306) can be less than the absolute value of the radius of curvature of the twelfth surface (S12). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (307) can be greater than the absolute value of the radius of curvature of the fourteenth surface (S14). The absolute value of the radius of curvature of the fifteenth surface (S15) of the eighth lens (108) can be less than the absolute value of the radius of curvature of the sixteenth surface (S16).

[0411] The ratio of the radii of curvature of each lens can satisfy the following condition.

[0412] Condition 1: 5 < |L1R1 / L1R2| < 6

[0413] Condition 2: 0.1 < |L2R1 / L2R2| < 0.5

[0414] Condition 3: 1.5 < |L3R1 / L3R2| < 2.5

[0415] Condition 4: 2 < L4R1 / L4R2 < 2.5

[0416] Condition 5: 1 < |L5R1 / L5R2| < 2

[0417] Condition 6: 0.5 < |L6R1 / L6R2| < 1

[0418] Condition 7: 1000 < |L7R1 / L7R2| < 1100

[0419] Condition 8: 0.1 < |L8R1 / L8R2| < 0.5

[0420] When the center thickness (CT) of a lens is described based on its optical axis, the center thickness (CT5) of the fifth lens (305) is the largest among the lenses, and the center thickness (CT7) of the seventh lens (307) is the smallest among the lenses. The difference between the maximum and minimum center thicknesses within a lens can be in the range of 1.5 mm or greater and 2.5 mm or less.

[0421] The center thickness of each lens can satisfy any one of the following conditions:

[0422] Condition 1: CT2, CT4, CT5, CT6, CT8 > CT1 > CT3, CT7

[0423] Condition 2: CT4, CT5, CT6, CT8 > CT2 > CT1, CT3, CT7

[0424] Condition 3: CT1, CT2, CT4, CT5, CT6, CT8 > CT3 > CT7

[0425] Condition 4: CT6, CT8 > CT4 > CT1, CT2, CT3, CT5, CT7

[0426] Condition 5: CT4, CT6, CT8 > CT5 > CT1, CT2, CT3, CT7

[0427] Condition 6: CT6 > CT1, CT2, CT3, CT4, CT5, CT7, CT8

[0428] Condition 7: CT1, CT2, CT3, CT4, CT5, CT6, CT8 > CT7

[0429] Condition 8: CT6 > CT8 > CT1, CT2, CT3, CT4, CT5, CT7

[0430] To illustrate the center gap (CG) between lenses, the center gap (CG1) between the first lens (301) and the second lens (302) can be the maximum value, and at least one of the center gap (CG4) between the fourth lens and the fifth lens (304, 305) and the center gap (CG6) between the sixth lens and the seventh lens (306, 307) can be the minimum value. In the spaced lens gaps, the difference between the maximum and minimum center gaps can be 2 mm or greater, for example, in the range of 2.5 mm to 3.5 mm.

[0431] The center gap between each lens can meet the following conditions.

[0432] Condition 1: CG1 > CG2, CG3, CG4, CG5, CG6, CG7

[0433] Condition 2: CG1, CG3, CG5, CG7 > CG2 > CG4, CG6

[0434] Condition 3: CG1 > CG3 > CG2, CG4, CG5, CG6, CG7

[0435] Condition 4: CG1, CG2, CG3, CG5, CG7 > CG4 = CG6

[0436] Condition 5: CG1, CG3 > CG5 > CG2, CG4, CG6, CG7

[0437] Condition 6: CG1, CG3, CG5 > CG7 > CG2, CG4, CG6

[0438] To illustrate the effective diameter, the lens having the maximum effective diameter can be a glass lens. The lens having the maximum effective diameter can be the first lens (301). Here, the effective diameter is the average of the effective diameter on the object side and the effective diameter on the sensor side of each lens. The lens surface having the maximum effective diameter can be the first surface (S1) of the first lens (301).

[0439] The lens with the smallest effective diameter can be a lens disposed between the first lens (301) and the aperture (STOP). The lens with the smallest effective diameter can be a fifth lens (305). The lens surface with the smallest effective diameter can be the ninth surface (S9) of the fifth lens (305). The effective diameter of a lens made of plastic can be smaller than that of a lens made of glass. The lens made of plastic can be disposed adjacent to the image sensor.

[0440] The effective diameter of each lens can satisfy any of the following conditions.

[0441] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0442] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0443] Condition 3: CA_L1, CA_L2, CA_L8 > CA_L3 > CA_L4, CA_L5, CA_L6, CA_L7

[0444] Condition 4: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L5

[0445] Condition 5: CA_L1, CA_L2, CA_L3, CA_L4, CA_L6, CA_L7, CA_L8 > CA_L5

[0446] Condition 6: CA_L1, CA_L2, CA_L3, CA_L8 > CA_L6 > CA_L4, CA_L5, CA_L7

[0447] Condition 7: CA_L1, CA_L2, CA_L3, CA_L6, CA_L8 > CA_L7 > CA_L4, CA_L5

[0448] Condition 8: CA_L1, CA_L2 > CA_L8 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0449] To illustrate the refractive index, the refractive index of the second lens (302) can be the largest among the lenses and can be greater than 1.75, for example, greater than 1.8. Any or all of the third lens (303), sixth lens (306), and eighth lens (308) can have the smallest refractive index among the lenses. For example, the refractive index of the third lens (303), sixth lens (306), and eighth lens (308) can be the smallest among the lenses and can be less than 1.6, for example, less than 1.55. The difference between the maximum and minimum refractive index can be 0.2 or greater. By setting the lens near the object as a high-refractive-index lens and setting the lens adjacent to the glass lens and the lens adjacent to the image sensor (500) as low-refractive-index lenses made of plastic material, the incident efficiency can be improved, and the refractive force between the glass lens and the plastic lens can be adjusted to guide light to the image sensor (500).

[0450] The refractive index of each lens can satisfy any of the following conditions.

[0451] Condition 1: n1 = n5 > n2, n3, n4, n6, n7, n8

[0452] Condition 2: n2 > n1, n3, n4, n5, n6, n7, n8

[0453] Condition 3: n1, n2, n4, n5, n7 > n3 = n6 = n8

[0454] Condition 4: n2 > n4 = n7 > n1, n3, n5, n6, n8

[0455] To compare Abbe numbers, at least one of the first lens (301) and the fifth lens (305) has the largest Abbe number among the lenses, and may be 60 or greater. At least one of the fourth lens (304) and the seventh lens (307) has the smallest Abbe number 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 greater. By setting the Abbe number of the fifth lens (305), which is located at the center of the optical system (1200), to the maximum, and setting the Abbe number of the seventh lens (307), which has a low refractive index and is adjacent to the image sensor (500), to the minimum, the dispersion of light traveling between the glass lenses and the plastic lenses can be controlled, and the dispersion between the glass lenses and the plastic lenses can be increased to guide light to the image sensor (500).

[0456] The Abbe number of each lens can satisfy any of the following conditions.

[0457] Condition 1: v1 = v5 > v2, v3, v4, v6, v7, v8

[0458] Condition 2: v1, v3, v5, v6, v8 > v2 > v4, v7

[0459] Condition 3: v1, v5 > v3 = v6 = v8 > v2, v4, v7

[0460] Condition 4: v1, v2, v3, v5, v6, v8 > v4 = v7

[0461] The focal lengths (F1, F3, F4, F7) of the first, third, fourth, and seventh lenses (301, 303, 304, 307) can have a negative (-) sign. The first, third, fourth, and seventh lenses (301, 303, 304, 307) can have a negative (-) refractive power. The focal lengths (F2, F5, F6, F8) of the second, fifth, sixth, and eighth lenses (302, 305, 306, 308) can have a positive (+) sign. The second, fifth, sixth, and eighth lenses (302, 305, 306, 308) can have a positive (+) refractive power.

[0462] In addition, the seventh lens (307) and the eighth lens (308), which are arranged adjacent to each other, can satisfy the following conditions.

[0463] Condition 1: The refractive index of a lens with positive refractive power < the refractive index of a lens with negative refractive power.

[0464] Condition 2: The dispersion value of a lens with positive refractive power is greater than the dispersion value of a lens with negative refractive power.

[0465] Here, in the plastic lens, the eighth lens (308) has a positive refractive power, and the seventh lens (307) has a negative refractive power, such that, according to conditions 1 and 2, the refractive index of the eighth lens (308) is less than that of the seventh lens (307), and the dispersion value of the eighth lens (308) is greater than that of the seventh lens (307). The chromatic aberration appearing in the plastic lens can be corrected by the plastic lens. In addition, since the seventh lens (307) and the eighth lens (308), which are plastic lenses arranged successively, satisfy the condition that the difference in refractive index is 0.1 or greater and 0.15 or less, and the difference in Abbe number is 20 or greater and 50 or less, the chromatic aberration appearing in the plastic lens can be compensated by the plastic lens.

[0466] The optical system generates chromatic aberration, which is corrected by using a cemented lens or two lenses arranged sequentially. As the temperature changes from low to high, the lens repeatedly contracts and expands. Since lenses made of the same material exhibit the same amount of change in lens properties due to temperature variations, correcting chromatic aberration between lenses made of the same material is effective even when the temperature changes. Therefore, in the third embodiment of the invention, chromatic aberration occurring in a plastic lens can be corrected by using a seventh lens (307) and an eighth lens (308).

[0467] When comparing focal lengths in absolute terms, the fourth lens (304) has the largest focal length among the lenses, and it can be 55 or greater and 65 or less. The sixth lens (306) has the smallest focal length among the lenses, and the absolute value of the focal length of the sixth lens (306) can be 7 or greater and 9 or less.

[0468] The absolute value of the focal length of each lens can satisfy any of the following conditions.

[0469] Condition 1: |f2|, |f4| > |f1| > |f3|, |f5|, |f6|, |f7|, |f8|

[0470] Condition 2: |f4| > |f2| > |f1|, |f3|, |f5|, |f6|, |f7|, |f8|

[0471] Condition 3: |f1|, |f2|, |f4|, |f8| > |f3| > |f5|, |f6|, |f7|

[0472] Condition 4: |f4| > |f1|, |f2|, |f3|, |f5|, |f6|, |f7|, |f8|

[0473] Condition 5: |f1|, |f2|, |f3|, |f4|, |f8| > |f5| > |f6|, |f7|

[0474] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5|, |f7|, |f8| > |f6|

[0475] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f8| > |f7| > |f6|

[0476] Condition 8: |f1|, |f2|, |f4| > |f8| > |f3|, |f5|, |f6|, |f7|

[0477] The thickness (T1) of the first lens (301) can have a difference of 2 times or more between the maximum and minimum thickness, for example, in the range of 2 to 2.5 times, and the center thickness (CT1) can be the minimum and the edge thickness (ET1) can be the maximum. The thickness (T2) of the second lens (302) can be the maximum thickness in the range of 1 to 1.5 times the minimum thickness. The second lens (302) can have a center thickness (CT2) as the maximum and an edge thickness (ET2) as the minimum. The thickness (T3) of the third lens (303) can be the minimum at the center and the maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (304) can be the minimum at the center and the maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (305) can be the maximum at the center and the minimum at the edge, and the maximum thickness is in the range of 1.2 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (306) can be at its maximum at the center and at its minimum at the edge, with the maximum thickness ranging from 2 to 2.5 times the minimum thickness. The thickness (T7) of the seventh lens (307) can be at its minimum at the center and at its maximum at the edge, with the maximum thickness ranging from 2 to 2.5 times the minimum thickness. The thickness (T8) of the eighth lens (308) can be at its maximum at the center and at its minimum at the edge, with the maximum thickness ranging from 1 to 1.2 times the minimum thickness.

[0478] The ratio of the center thickness to the edge thickness of each lens can be called the thickness ratio. When the ratio of the larger to the smaller center thickness to the smaller edge thickness satisfies 2 to 2.5, the lens is easy to manufacture and can be advantageous in terms of yield.

[0479] The thickness of each lens can satisfy any of the following conditions.

[0480] Condition 1: 0.3 < CT1 / ET1 < 0.7, 2 < ET1 / CT1 < 2.5

[0481] Condition 2: 1 < CT2 / ET2 < 1.5, 0.5 < ET2 / CT2 < 1

[0482] Condition 3: 0.3 < CT3 / ET3 < 0.7, 1.5 < ET3 / CT3 < 2

[0483] Condition 4: 0.8 < CT4 / ET4 < 1.2, 0.8 < ET4 / CT4 < 1.2

[0484] Condition 5: 1.2 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0485] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0486] Condition 7: 0.3 < CT7 / ET7 < 0.7, 1.5 < ET7 / CT7 < 2

[0487] Condition 8: 2 < CT8 / ET8 < 2.5, 0.1 < ET8 / CT8 < 0.5

[0488] Condition 9: 1 < ΣCT / ΣET < 1.2, 0.5 < ΣET / ΣCT < 1

[0489] Among the gaps (G1 to G7) between the lenses, the first gap (G1) between the first lens and the second lens (301, 302) can have a maximum value in the center and a minimum value in the edge. The second gap (G2) between the second lens and the third lens (302, 303) can have a minimum value in the center and a maximum value in the edge. The third gap (G3) between the third lens and the fourth lens (303, 304) can have a minimum value in the edge and a maximum value in the center. The fourth gap (G4) between the fourth lens and the fifth lens (304, 305) can have a minimum value in the center and a maximum value in the edge. The fifth gap (G5) between the fifth lens and the sixth lens (305, 306) can have a minimum value in the center and a maximum value in the edge. The sixth gap (G6) between the sixth lens and the seventh lens (306, 307) can have a minimum value in the center and a maximum value in the edge. The seventh gap (G7) between the seventh lens and the eighth lens (307, 308) can be at its maximum value at the center and at its minimum value at the edge.

[0490] Figure 28 , Figure 30 and Figure 32 It is shown Figure 23 The graphs show the diffraction MTF (modulation transfer function) curves of the optical system at room temperature, low temperature, and high temperature, and also show the modulation ratio according to the spatial frequency. Figure 28 , Figure 30 and Figure 32 As shown, in the third embodiment of the present invention, the deviation of the MTF at low or high temperatures based on room temperature can be less than 10%, i.e., 7% or less.

[0491] Figure 29, Figure 31 and Figure 33 It is shown Figure 23 The graphs show the aberration characteristics of the optical system at room temperature, low temperature, and high temperature. Figure 29 , Figure 31 and Figure 33 In the aberration curve diagram, spherical aberration (longitudinal spherical aberration), astigmatism curve, and distortion are measured from left to right. Figure 29 , Figure 31 and Figure 33 In the graph, the X-axis represents focal length (mm) and distortion rate (%), while the Y-axis represents image height. Additionally, the spherical aberration graph is for light in the wavelength bands of approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm, and the astigmatism and distortion graph is for light in the wavelength band of approximately 546 nm. Figure 29 , Figure 31 and Figure 33 In the aberration diagram, the closer the curves at room temperature, low temperature, and high temperature are to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1200) according to the third embodiment has measurements close to the Y-axis in almost all regions. That is, the optical system (1200) according to the third embodiment has improved resolution and good optical performance not only at the center of the field of view (FOV) but also at the edges. 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 in the range of 18 to 27 degrees; and the high temperature can be 85 degrees or higher, for example, in the range of 85 to 105 degrees. Therefore, it can be seen that from... Figure 29 , Figure 31 and Figure 33 The decrease in brightness ratio (modulation) from low temperature to high temperature is less than 10%, for example 5% or less, or almost unchanged.

[0492] Table 9 compares the changes in optical properties such as EFL, BFL, F-number (F#), TTL, and field of view (FOV_H) of the optical system according to the third embodiment at room temperature, low temperature, and high temperature. It can be seen that the rate of change of optical properties at low temperature is 5% or less, for example 3% or less, relative to room temperature.

[0493] Table 9

[0494]

[0495] Therefore, as shown in Table 9, it can be seen that the change in optical characteristics (e.g., the change rates of effective focal length (EFL), TTL, BFL, F-number, and field of view (FOV_H)) according to the temperature change from low temperature to high temperature is less than 10%, i.e., less than 5%, for example, within the range of 0% to 5%. This enables the design of temperature compensation for plastic lenses even when using at least one or two or more plastic lenses, thereby preventing a reduction in the reliability of optical characteristics.

[0496] The optical system of the second embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the central portion of the field of view (FOV) but also at the edge portion.

[0497] The optical systems (1000, 1100, 1200) according to the first to third embodiments disclosed above can satisfy at least one or two or more of the following-described mathematical expressions. Therefore, the optical systems (1000, 1100, 1200) according to the first to third embodiments can have improved optical characteristics. For example, when the optical system (1000, 1100, 1200) satisfies at least one mathematical expression, the optical system (1000, 1100, 1200) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the central portion of the field of view (FOV) but also at the edge portion. In addition, the optical systems (1000, 1100, 1200) can have improved resolution. Further, the thickness of the lens described in the mathematical formula on the optical axis (OA) and the gap between adjacent lenses on the optical axis (OA) can be referred to the first to third embodiments disclosed above.

[0498] [Mathematical Expression 1]

[0499] 20 < L1R2 < 50

[0500] In Mathematical Expression 1, L1R2 is the radius of curvature of the sensor-side surface (second surface (S2)) of the first lens (101, 201, 301). When Mathematical Expression 1 is satisfied, the gap between the first lens (101, 201, 301) and the second lens (102, 202, 302) can be ensured during lens assembly, and assembly can be facilitated. In addition, when Mathematical Expression 1 is satisfied, the influence on incident light and TTL can be controlled. In the first embodiment, Mathematical Expression 1 can preferably satisfy 20 < L1R2 < 30, in the second embodiment, Mathematical Expression 1 can preferably satisfy 40 < L1R2 < 50, and in the third embodiment, Mathematical Expression 1 can preferably satisfy 30 < L1R2 < 40.

[0501] [Mathematical Expression 2]

[0502] 1.7 < n² < 1.9

[0503] In mathematical expression 2, n2 is the refractive index of the second lens (102, 202, 302). In the optical system (1000, 1100, 1200), the lens closest to the object in the plastic material lens is made of glass, and when this lens is a high-refractive-index lens, it can maintain its optical performance according to temperature changes. In the first to third embodiments, mathematical expression 2 can preferably satisfy 1.8 < n2 < 1.9.

[0504] [Mathematical Expression 3]

[0505] 20 < v2 < 30

[0506] In mathematical expression 3, v2 is the Abbe number of the second lens (102, 202, 302). In the optical system (1000, 1100, 1200), the lens closest to the object side of the plastic material lens is made of glass, and when this lens is a high-dispersion lens, it can maintain its optical performance according to temperature changes. In the first to third embodiments, mathematical expression 3 can preferably satisfy 22 < v2 < 27.

[0507] [Mathematical Expression 4]

[0508] 0 < CG1 / ΣCG < 0.5

[0509] In mathematical expression 4, CG1 is the center gap between the first lens (101, 201, 301) and the second lens (102, 202, 302), and ΣCG is the sum of the gaps between adjacent lenses. When mathematical expression 4 is satisfied, the light emitted from the first lens (101, 201, 301), which has a significant impact on the entire optical system, is set up to enter the optical path of the remaining lenses, and the optical system can have good optical performance at the set viewing angle and focal length. In the first to third embodiments, mathematical expression 4 can preferably satisfy 0 < CG1 / ΣCG < 0.3.

[0510] [Mathematical Expression 5]

[0511] 0 < CG1 / ΣCT < 0.5

[0512] In mathematical expression 5, CG1 is the central gap between the first lens (101, 201, 301) and the second lens (102, 202, 302), and ΣCT is the sum of the central thicknesses of the lenses. When mathematical expression 5 is satisfied, the light emitted from the first lens (101, 201, 301), which has a significant impact on the entire optical system, is set up to enter the optical path of the remaining lenses, and the optical system can have good optical performance at the set viewing angle and focal length. In the first to third embodiments, mathematical expression 5 can preferably satisfy 0 < CG1 / ΣCT < 0.2.

[0513] [Mathematical Expression 6]

[0514] 0 < CG1 / TTL < 0.3

[0515] In mathematical expression 6, CG1 is the center gap between the first lens (101, 201, 301) and the second lens (102, 202, 302), and the relationship between CG1 and TTL can be set. TTL is the distance (mm) on the optical axis (OA) from the center of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500). When mathematical expression 6 is satisfied, the light emitted from the first lens (101, 201, 301), which has a significant impact on the entire optical system, is set for the optical path to enter the remaining lenses, and the optical system can have good optical performance at the set viewing angle and focal length. In the first to third embodiments, mathematical expression 6 can preferably satisfy 0 < CG1 / TTL < 0.1.

[0516] [Mathematical Expression 7]

[0517] 0.3 < ΣCT / TTL < 0.8

[0518] Mathematical expression 7 can set the relationship between the sum of the center thicknesses ΣCT of the first to eighth lenses (101 to 108, 201 to 208, 301 to 308) and TTL, where TTL is the distance (mm) from the center of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) along the optical axis (OA). To reduce TTL, a large amount of light refraction must occur. To refract a large amount of light, the refractive power of the lens must increase, and to increase the refractive power, the lens becomes thicker. When the sum of the lens thicknesses is less than the lower limit of mathematical expression 7, the sum of the lens thicknesses decreases, and the refractive power weakens. When the sum of the lens thicknesses is greater than the upper limit of mathematical expression 7, there is a problem that the sum of the lens thicknesses increases excessively, causing the TTL to increase. In the first to third embodiments, mathematical expression 7 preferably satisfies 0.5 < ΣCT / TTL < 0.7.

[0519] [Mathematical Expression 8]

[0520] 0.1 < ΣCG / TTL < 0.5

[0521] Mathematical expression 8 can set the relationship between the sum of the gaps ΣCG between adjacent lenses (101 to 108, 201 to 208, 301 to 308) and TTL, where TTL is the distance (mm) from the center of the first surface (S1) to the upper surface of the image sensor (500) on the optical axis (OA). To reduce TTL, a large amount of light refraction must occur. To refract a large amount of light, the refractive power of the lens must increase, and to increase the refractive power, the lens becomes thicker. When the sum of the lens thickness is less than the lower limit of mathematical expression 8, the sum of the lens thickness decreases, and the refractive power weakens, thus becoming weaker than desired. When the sum of the lens thickness is greater than the upper limit of mathematical expression 8, there is a problem that the sum of the lens thickness increases excessively, causing the TTL to increase. In the first to third embodiments, mathematical expression 8 can preferably satisfy 0.2 < ΣCG / TTL < 0.4.

[0522] [Mathematical Expression 9]

[0523] 1 < ΣCT / ΣCG < 3

[0524] In mathematical expression 9, ΣCT is the sum of the center thicknesses of the lenses, and ΣCT is the sum of the gaps between adjacent lenses. When mathematical expression 9 is satisfied, the optical system can have good optical performance at a set viewing angle and focal length, and the TTL can be reduced. In the first to third embodiments, mathematical expression 9 can preferably satisfy 1.5 < ΣCT / ΣCG < 2.5.

[0525] [Mathematical Expression 10]

[0526] 25 < ΣAbb / ΣIndex < 30

[0527] In mathematical expression 10, ΣAbb refers to the sum of the Abbe numbers of each of the multiple lenses, and ΣIndex refers to the sum of the refractive indices of each of the multiple lenses at the d-line. When mathematical expression 10 is satisfied, the optical system (1000, 1100, 1200) can have improved aberration characteristics and resolution. Mathematical expression 10 can control optical characteristics by setting the sum of the Abbe numbers and the sum of the refractive indices of the lenses. In the first to third embodiments, preferably, mathematical expression 10 can satisfy 26 < ΣAbb / ΣIndex < 28.

[0528] [Mathematical Expression 11]

[0529] 1 < ΣCT / ΣET < 2

[0530] In mathematical expression 11, ΣCT is the sum of the center thickness of the lens, and ΣET is the sum of the thicknesses at the edges (i.e., the ends of the effective area of ​​the lens). When mathematical expression 11 is satisfied, the optical system can have good optical performance at a set viewing angle and focal length, and the TTL can be reduced. In the first to third embodiments, mathematical expression 11 can preferably satisfy 1 < ΣCT / ΣET < 1.5.

[0531] [Mathematical Expression 12]

[0532] 0.3 < CT1 / ET1 < 0.8

[0533] In mathematical expression 12, CT1 is the center thickness of the first lens (101, 201, 301), and ET1 is the edge thickness of the first lens (101, 201, 301). Thus, factors affecting the viewing angle of the optical system can be set, and factors affecting the effective focal length (EFL) can also be set. In the first to third embodiments, mathematical expression 12 preferably satisfies 0.4 < CT1 / ET1 < 0.7.

[0534] [Mathematical Expression 13]

[0535] 1 < CT8 / ET8 < 2.5

[0536] In mathematical expression 13, CT8 is the center thickness of the eighth lens (108, 208, 308), and ET8 is the edge thickness of the eighth lens (108, 208, 308). Thus, factors affecting the viewing angle of the optical system can be set, and factors affecting the effective focal length (EFL) can also be set. In the first to third embodiments, mathematical expression 13 preferably satisfies 1.5 < CT8 / ET8 < 2.2.

[0537] [Mathematical Expression 14]

[0538] 1 < GLCa_AVER / PLCa_AVER < 2

[0539] In mathematical expression 14, GLCa_AVER represents the average effective diameter of the glass lens, and PLCa_AVER represents the average effective diameter of the plastic lens. The lens barrel containing the lens unit has at least one inner lens barrel, and at least some of the plastic lenses included in the lens unit can be disposed within the inner lens barrel. In the case of plastic lenses, due to their significant expansion at high temperatures, a wider space is required within the lens barrel. In mathematical expression 14, by setting the effective diameter sizes of the glass lens and the plastic lens, the degradation of optical properties due to temperature changes can be suppressed, and the optical system (1000, 1100, 1200) can control the incident light and set factors affecting aberrations. In the first to third embodiments, mathematical expression 14 preferably satisfies 1.2 < GLCa_AVER / PLCa_AVER < 1.7.

[0540] [Mathematical Expression 15]

[0541] 1 < CA_L1S1 / CA_L1S2 < 2

[0542] In mathematical expression 15, CA_L1S1 represents the effective diameter of the first surface (S1) of the first lens (101, 201, 301), and CA_L1S2 represents the effective diameter of the second surface (S2) of the first lens (101, 201, 301). When mathematical expression 15 is satisfied, the degradation of optical properties due to temperature changes can be suppressed, and the optical system (1000, 1100, 1200) can control the incident light and set factors affecting aberrations. In the first to third embodiments, mathematical expression 15 can preferably satisfy 1.2 < CA_L1S1 / CA_L1S2 < 1.6.

[0543] [Mathematical Expression 16]

[0544] 1 < CA_L1 / CA_L8 < 2.5

[0545] In mathematical expression 16, CA_L1 represents the effective diameter of the first lens (101, 201, 301), and CA_L8 represents the effective diameter of the eighth lens (108, 208, 308). The lens barrel containing the lens units has at least one inner barrel, and at least some of the plastic lenses included in the lens units can be disposed within the inner barrel. In the case of lenses made of plastic, significant expansion occurs at high temperatures, requiring a wider space within the lens barrel. Therefore, when mathematical expression 16 is satisfied (mathematical expression 16 sets the relationship between the effective diameter of the first lens (101, 201, 301) made of glass and the effective diameter of the eighth lens (108, 208, 308) made of plastic), the degradation of optical properties due to temperature changes can be suppressed, and the optical system (1000, 1100, 1200) can control the incident light and set factors affecting aberrations. In the first to third embodiments, the mathematical expression 16 can preferably satisfy 1.5 < CA_L1 / CA_L8 < 2.2.

[0546] [Mathematical Expression 17]

[0547] 3 < CA_L1 / ImgH < 5

[0548] Mathematical expression 17 can set the relationship between the effective diameter CA_L1 of the first lens (101, 201, 301) and ImgH, which is half the maximum diagonal length of the image sensor. If mathematical expression 17 is satisfied, a TTL suitable for a vehicle optical system is satisfied, and the set viewing angle is satisfied. If it is less than the lower limit of mathematical expression 17, the effective diameter of the lens set in the optical system (1000, 1100, 1200) becomes maximum, which leads to the problem of a longer TTL. If it exceeds the upper limit of mathematical expression 17, there is a problem that the viewing angle becomes too large than the viewing angle satisfied by the optical system (1000, 1100, 1200). In the first to third embodiments, mathematical expression 17 can preferably satisfy 3.5 < CA_L1 / ImgH < 4.8.

[0549] [Mathematical Expression 18]

[0550] 1 < CT_Max / CG_Max < 2

[0551] In mathematical expression 18, CT_Max is the maximum center thickness of the lens, and CG_Max is the maximum gap between adjacent lenses. When mathematical expression 18 is satisfied, the optical system can have good optical performance at the set viewing angle and focal length, and the TTL can be reduced. In the first to third embodiments, mathematical expression 18 can preferably satisfy 1 < CT_Max / CG_Max < 1.7.

[0552] [Mathematical Expression 19]

[0553] 2 < CA_max / CA_min < 3

[0554] In mathematical expression 19, CA_max represents the maximum effective diameter between the object-side and sensor-side surfaces of the lens, and CA_Min represents the minimum effective diameter between the object-side and sensor-side surfaces of the lens. When mathematical expression 19 is satisfied, the optical system can be configured with a slim and compact structure while maintaining optical performance. In the first to third embodiments, mathematical expression 19 can preferably satisfy 2.5 < CA_max / CA_min < 3.

[0555] [Mathematical Expression 20]

[0556] 1 < CA_max / CA_Aver < 2

[0557] In mathematical expression 20, CA_max represents the maximum effective diameter between the object-side surface and the sensor-side surface of the lens, and CA_Aver represents the average effective diameter between the object-side surface and the sensor-side surface of the lens. When mathematical expression 20 is satisfied, the optical system can be configured with a slim and compact structure while maintaining optical performance. In the first to third embodiments, mathematical expression 20 can preferably satisfy 1.5 < CA_max / CA_Aver < 2.

[0558] [Mathematical Expression 21]

[0559] 0.5 < CA_min / CA_Aver < 1

[0560] In mathematical expression 21, CA_Min represents the minimum effective diameter between the object-side surface and the sensor-side surface of the lens, and CA_Aver represents the average effective diameter between the object-side surface and the sensor-side surface of the lens. When mathematical expression 21 is satisfied, the optical system can be configured with a slim and compact structure while maintaining optical performance. In the first to third embodiments, mathematical expression 21 can preferably satisfy 0.6 < CA_min / CA_Aver < 0.8.

[0561] [Mathematical Expression 22]

[0562] 4 < CA_max / ImgH < 5

[0563] In mathematical expression 22, CA_max represents the maximum effective diameter between the object-side surface and the sensor-side surface of the lens, and Imgh represents half the maximum diagonal length of the image sensor (500). When mathematical expression 22 is satisfied, the optical system can maintain good optical performance and can be configured with a slim and compact structure. In the first to third embodiments, mathematical expression 22 can preferably satisfy 4 < CA_max / Imgh < 4.7.

[0564] [Mathematical Expression 23]

[0565] 30 < TTL < 40

[0566] In mathematical expression 23, TTL (Total Track Length) refers to the distance (mm) along the optical axis (OA) from the center of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500). A suitable vehicle optical system can be provided when mathematical expression 23 is satisfied. In the first to third embodiments, mathematical expression 23 can preferably satisfy 32 < TTL < 38.

[0567] [Mathematical Expression 24]

[0568] 4 < ImgH < 5

[0569] In mathematical expression 24, ImgH represents half the maximum diagonal length of the image sensor (500). Mathematical expression 24 can set the diagonal size of the image sensor (500) and provide an optical system with a sensor size suitable for a vehicle. In the first to third embodiments, mathematical expression 24 can preferably satisfy 4 < ImgH < 4.5.

[0570] [Mathematical Expression 25]

[0571] 0.8 < BFL < 1.5

[0572] In mathematical expression 25, BFL is the optical axis distance from the center of the image sensor (500) to the sensor side of the final lens. When mathematical expression 25 is satisfied, the mounting space for the filter 600 and the cover glass can be ensured, the assembly of components can be improved by the gap between the image sensor (500) and the final lens, and the reliability of the connection can be improved. In the first to third embodiments, mathematical expression 25 can preferably satisfy 0.9 < BFL < 1.2. When BFL is less than the range of mathematical expression 25, a portion of the light traveling to the image sensor may not be transmitted to the image sensor, which may lead to a reduction in resolution. When BFL exceeds the range of mathematical expression 25, stray light may be introduced, which may degrade the aberration characteristics of the optical system.

[0573] [Mathematical Expression 26]

[0574] 5 < F < 6

[0575] Mathematical expression 26 can set the total focal length F to suit the vehicle's optical system. In the first to third embodiments, mathematical expression 26 can satisfy 5 < F < 5.5.

[0576] [Mathematical Expression 27]

[0577] 110 < FOV_H < 150

[0578] In mathematical expression 27, FOV_H represents the horizontal viewing angle (degrees) of the optical system (1000, 1100, 1200) and can provide a viewing angle suitable for the vehicle's optical system. In the first to third embodiments, preferably, 110 < FOV_H < 130 can be satisfied.

[0579] [Mathematical Expression 28]

[0580] 1 < TTL / CA_max < 3

[0581] In mathematical expression 28, CA_max refers to the maximum effective diameter (mm) among the object-side and sensor-side of the plurality of lenses, and TTL (total track length) refers to the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500). Mathematical expression 28 sets the relationship between the total optical axis length and the maximum effective diameter of the optical system, thereby providing an improved vehicle optical system. In the first to third embodiments, mathematical expression 28 may preferably satisfy 1.5 < TTL / CA_max < 2.5.

[0582] [Mathematical Expression 29]

[0583] 8 < TTL / ImgH < 9

[0584] In mathematical expression 29, TTL (Total Track Length) refers to the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) along the optical axis (OA), and ImgH refers to half the maximum diagonal length of the image sensor (500). When mathematical expression 29 is satisfied, the optical system (1000, 1100, 1200) can have a TTL suitable for application to the vehicle image sensor (500), thereby providing improved image quality. In the first to third embodiments, mathematical expression 29 can preferably satisfy 8.2 < TTL / ImgH < 8.7.

[0585] [Mathematical Expression 30]

[0586] 0.1 < BFL / ImgH < 0.5

[0587] In mathematical expression 30, BFL is the optical axis distance from the image sensor (500) to the center of the sensor side of the final lens, and ImgH means half the maximum diagonal length of the image sensor (500). When mathematical expression 30 is satisfied, the optical system (1000, 1100, 1200) can ensure that the BFL (back focal length) for the size of the applied vehicle image sensor (500) can be set, the gap between the final lens and the image sensor (500) can be set, and good optical characteristics can be achieved in both the central and peripheral portions of the field of view (FOV). In the first to third embodiments, mathematical expression 30 can preferably satisfy 0.1 < BFL / ImgH < 0.3.

[0588] [Mathematical Expression 31]

[0589] 30 < TTL / BFL < 40

[0590] In mathematical expression 31, TTL (Total Track Length) refers to the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500), and BFL refers to the optical axis distance from the image sensor (500) to the center of the sensor-side surface of the last lens. When mathematical expression 31 is satisfied, the optical system (1000, 1100, 1200) can ensure BFL. In the first to third embodiments, mathematical expression 31 can preferably satisfy 32 < TTL / BFL < 37.

[0591] [Mathematical Expression 32]

[0592] 6 < TTL / F < 8

[0593] In mathematical expression 32, TTL (Total Track Length) refers to the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) on the optical axis (OA), and F is the effective focal length of the optical system. Therefore, an optical system for driver assistance systems can be provided. When the optical system (1000, 1100, 1200) according to the embodiment satisfies mathematical expression 32, the optical system (1000, 1100, 1200) can have an appropriate focal length within the set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length even when the temperature changes from low to high. If the value is less than the lower limit of mathematical expression 32, the refractive power of the lens needs to be increased, making it difficult to correct spherical aberration or distortion aberration. If the value is greater than the upper limit of mathematical expression 32, the effective diameter or TTL of the lens may become longer, which may lead to a problem where the imaging lens system becomes larger. In the first to third embodiments, the mathematical expression 32 can preferably satisfy 6 < TTL / F < 7.

[0594] [Mathematical Expression 33]

[0595] 5 < F / BFL < 7

[0596] In mathematical expression 33, F refers to the effective focal length of the optical system, and BFL refers to the optical axis distance from the image sensor (500) to the center of the sensor side of the final lens. When mathematical expression 33 is satisfied, the optical system (1000, 1100, 1200) can have a set viewing angle and an appropriate focal length, and can provide a vehicle optical system. Furthermore, the optical system (1000, 1100, 1200) can minimize the gap between the final lens and the image sensor (500), and therefore can have good optical characteristics at the edge of the field of view (FOV). In the first to third embodiments, preferably, expression 33 can satisfy 5 < F / BFL < 6.

[0597] [Mathematical Expression 34]

[0598] 1 < F / ImgH < 3

[0599] In mathematical expression 34, F refers to the effective focal length of the optical system, and ImgH refers to half the maximum diagonal length of the image sensor (500). Such an optical system (1000, 1100, 1200) can have improved aberration characteristics for the size of the vehicle image sensor (500). In the first to third embodiments, mathematical expression 34 can preferably satisfy 1 < F / ImgH < 2.

[0600] [Mathematical Expression 35]

[0601]

[0602] In mathematical expression 35, Z can refer to sag, which is the distance along the optical axis from any point on the aspherical surface to the vertex of the aspherical surface. Y can refer to the distance from any point on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. c can refer to the curvature of the lens, and K can refer to the conic constant. Furthermore, A, B, C, D, E, and F can refer to the aspherical constant.

[0603] The optical systems (1000, 1100, 1200) of the first to third embodiments can satisfy at least one or two or more mathematical expressions from mathematical expression 1 to mathematical expression 34. In this case, the optical systems (1000, 1100, 1200) can have improved optical characteristics. Specifically, when the optical systems (1000, 1100, 1200) satisfy at least one or two or more mathematical expressions from mathematical expression 1 to mathematical expression 34, the optical systems (1000, 1100, 1200) can have improved resolution and improved aberration and distortion characteristics. Furthermore, the optical systems (1000, 1100, 1200) can ensure the BFL (back focal length) for the vehicle image sensor (500), compensate for the degradation of optical characteristics due to temperature changes, and minimize the gap between the final lens and the image sensor (500), thereby providing good optical performance in the central and peripheral portions of the field of view (FOV).

[0604] Table 10 shows the resulting values ​​of mathematical expressions 1 to 34 in the optical system (1000, 1100, 1200) according to the embodiments. Referring to Table 10, it can be seen that the optical system (1000, 1100, 1200) satisfies at least one, two or more, or three or more of mathematical expressions 1 to 34. In detail, it can be seen that the optical system (1000, 1100, 1200) according to the embodiments satisfies all of mathematical expressions 1 to 34. Therefore, the optical system (1000, 1100, 1200) can have good optical performance at both the central and peripheral portions of the field of view (FOV) and can have excellent optical characteristics.

[0605] Table 10

[0606]

[0607]

[0608] Figure 34 This is an example of a plan view of a vehicle employing a camera device module or optical system according to an embodiment of the present invention. (Refer to...) Figure 34According to an embodiment of the present invention, a vehicle camera system includes an image generation unit (11), a first information generation unit (12), a second information generation unit (21, 22, 23, 24, 25, 26), and a control unit (14). The image generation unit (11) may include at least one camera module (31) disposed in the vehicle and may capture images of the front of the vehicle and / or the driver to generate a front image or interior image of the vehicle. The image generation unit (11) may use the camera module (31) to capture images of the surroundings and the front of the vehicle in one or more directions to generate an image of the surroundings of the vehicle. Here, the front image and the surrounding image may be digital images and may include color images, black and white images, infrared images, etc. Furthermore, the front image and the surrounding image may include still images and moving images. The image generation unit (11) provides the driver image, the front image, and the surrounding image to the control unit (14). Next, the first information generation unit (12) may include at least one radar and / or camera device disposed in the vehicle and detects the front of the vehicle to generate first detection information. Specifically, the first information generation unit (12) is installed in the vehicle and detects the position and speed of the vehicle in front of the vehicle, the presence and position of pedestrians, etc., to generate the first detection information.

[0609] By using the first detection information generated by the first information generation unit (12), the distance between the vehicle and the vehicle in front can be kept at a constant level, and the stability of vehicle operation can be improved under specific preset conditions, such as when the driver wants to change the vehicle's driving lane or when reversing. The first information generation unit (12) provides the first detection information to the control unit (14). The second information generation units (21, 22, 23, 24, 25, 26) detect each side of the vehicle based on the forward image generated by the image generation unit (11) and the first detection information generated by the first information generation unit (12), and generate second detection information. Specifically, the second information generation units (21, 22, 23, 24, 25, 26) may include at least one radar and / or camera device installed in the vehicle, and can detect the position and speed of vehicles located on the side of the vehicle or capture images. Here, the second information generation units (21, 22, 23, 24, 25, 26) may be respectively installed at the two front corners, the side mirrors, and the rear center and the two rear corners of the vehicle.

[0610] At least one information generation unit of these vehicle camera systems may be equipped with an optical system as described in the disclosed embodiments above and a camera module having the optical system, and may provide or process information acquired by the user through the front, rear, each side or corner area of ​​the vehicle to enable autonomous driving or protect the vehicle and objects from the influence of the surrounding safety.

[0611] The optical system of the camera module according to an embodiment of the present invention can be installed in multiple units in a vehicle for safety adjustment, enhanced autonomous driving functions, and increased convenience. Furthermore, the optical system of the camera module is used in the vehicle as a control component for systems such as Lane Keeping Assist System (LKAS), Lane Departure Warning System (LDWS), and Driver Monitoring System (DMS). Such a vehicle camera module achieves stable optical performance even under varying ambient temperatures and can be provided at a competitive price, thereby ensuring the reliability of vehicle components.

[0612] The features, structures, effects, etc., described in the above embodiments are included in at least one embodiment, but are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc., shown in each embodiment can be combined or modified by those skilled in the art to which the embodiments pertain, and implemented in other embodiments. Therefore, content related to such combinations and modifications should be interpreted as being included within the scope of the embodiments.

[0613] Furthermore, although the embodiments have been described above with reference to them, these are merely examples and do not limit the invention. Those skilled in the art will recognize that various modifications and applications not illustrated above are possible without departing from the essential characteristics of these embodiments. For example, each component specifically shown in the examples can be modified and implemented. Moreover, differences relating to such modifications and applications should be interpreted as including within the scope of the invention as defined in the appended claims.

Claims

1. An optical system comprising, from the object side to the sensor side: First lens; Second lens; The third lens has negative (-) refractive power; The fourth lens has negative (-) refractive power; The fifth lens has a positive (+) refractive power; as well as The sixth lens has a positive (+) refractive power; The seventh lens; as well as The eighth lens has positive (+) refractive power. Among the first to the eighth lenses, the second lens has the highest refractive index.

2. The optical system according to claim 1, in, The second lens is made of glass, and The third lens is made of plastic.

3. The optical system according to claim 1, in, The first lens and the seventh lens have negative (-) refractive power, and The second lens has a positive (+) refractive power.

4. The optical system according to claim 1, in, The distance between the first lens and the second lens on the optical axis is greater than the distance between the fifth lens and the sixth lens.

5. The optical system according to claim 1, in, Among the first to the eighth lenses, the fourth lens has the largest absolute value of focal length.

6. The optical system according to claim 1, in, The distance between the third lens and the fourth lens on the optical axis is greater than the distance between the seventh lens and the eighth lens.

7. The optical system according to claim 1, comprising: The first lens group includes the first lens to the fifth lens; as well as The second lens group includes the sixth to eighth lenses. The composite focal length of the first lens group is less than that of the second lens group.

8. The optical system according to claim 1, comprising: The first lens group includes the first lens to the fifth lens; as well as The second lens group includes the sixth to eighth lenses. The sign of the composite focal length of the first lens group is different from that of the composite focal length of the second lens group.

9. The optical system according to claim 1, comprising: The first lens group includes the first lens to the fifth lens; as well as The second lens group includes the sixth to eighth lenses. Wherein, the absolute value of the difference between the absolute value of the composite focal length of the first lens group and the absolute value of the focal length of the second lens group satisfies 1 or greater and 5 or less.

10. The optical system according to any one of claims 1 to 9, satisfying the following conditional expression. <Conditional expression> 1.7 < n² < 1.9, (in, n2 refers to the refractive power of the second lens.

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