Optical system and camera module including the same

Abstract

The optical system according to the embodiment includes first to third lenses arranged along an optical axis in a direction from an object side to a sensor side, The optical system satisfies 40 degrees≦FOV≦50 degrees, an object side surface and a sensor side surface of the first lens are spherical, and the first lens has a meniscus shape bulging toward the object side, The first lens is 1.7≦nt_1≦2.3 is satisfied, Satisfy 0.15≦D_1 / TTL≦0.3, Satisfies TTL≦9mm. (nt_1 is the refractive index of the first lens, TTL is the distance on the optical axis from the object side surface of the first lens to the top surface of the image sensor, D_1 is the thickness of the first lens on the optical axis, and FOV means the angle of view (FOV) of the optical system.)

Description

[Technical field]

[0001] The embodiments relate to an optical system having improved optical performance and a camera module including the same. [Background technology]

[0002] ADAS (Advanced Driving Assistance System) is an advanced driving support system for assisting a driver. The ADAS senses the situation ahead, judges the situation based on the sensing result, and controls the movement of the vehicle based on the situation judgment. For example, the ADAS detects a vehicle ahead and recognizes the lane. Then, when a target lane, a target speed, or a target ahead is judged, the vehicle's ESC (Electrical Stability Control), EMS (Engine Management System), MDPS (Motor Driven Power Steering), etc. are controlled. Typically, the ADAS is embodied as an automatic parking system, a low-speed city driving assistance system, a blind spot warning system, etc.

[0003] The sensor device for sensing the forward situation in the ADAS may include a GPS sensor, a laser scanner, a forward radar, and a Lidar. Typically, the sensor device is a camera for capturing images of the front, rear, and sides of the vehicle.

[0004] Such a camera is disposed inside or outside the vehicle to detect the situation around the vehicle. The camera may also be disposed inside the vehicle to detect the situation of the driver and passengers. For example, the camera may be positioned adjacent to the driver to capture the driver. This makes it possible to detect the driver's health condition, whether the driver is dozing, whether the driver has drunk alcohol, etc. The camera may be positioned adjacent to the passenger to capture the passenger. This makes it possible to detect the passenger's sleep status, health condition, etc. The camera may also provide information about the passenger to the driver.

[0005] The most important element for obtaining an image with the camera is the imaging lens that forms an image. Recently, there has been growing interest in high image quality or resolution. For this reason, research into optical systems including multiple lenses has been conducted. However, if the camera is exposed to a harsh environment (e.g., high temperature, low temperature, moisture, high humidity) outside or inside a vehicle, the characteristics of the optical system may change. This may result in a decrease in the optical characteristics or aberration characteristics of the camera.

[0006] Therefore, a new optical system and camera capable of solving the above problems is required. Summary of the Invention [Problem to be solved by the invention]

[0007] The embodiments seek to provide an optical system and a camera module with improved optical properties.

[0008] Additionally, the embodiments seek to provide an optical system and a camera module that can provide excellent optical characteristics in low-temperature or high-temperature environments.

[0009] Also, the embodiments provide an optical system and a camera module that can prevent or minimize changes in optical characteristics over various temperature ranges. [Means for solving the problem]

[0010] The optical system according to the embodiment includes first to third lenses arranged along an optical axis in a direction from an object side to a sensor side, The optical system satisfies 40 degrees≦FOV≦50 degrees, an object side surface and a sensor side surface of the first lens are spherical, and the first lens has a meniscus shape bulging toward the object side, The first lens is 1.7≦nt_1≦2.3 is satisfied, Satisfy 0.15≦D_1 / TTL≦0.3, Satisfies TTL≦9mm.

[0011] (nt_1 is the refractive index of the first lens, TTL is the distance on the optical axis from the object side surface of the first lens to the top surface of the image sensor, D_1 is the thickness of the first lens on the optical axis, and FOV means the angle of view (FOV) of the optical system.) Effect of the Invention

[0012] The optical system and camera module according to the embodiment have improved optical characteristics. More specifically, the lenses of the optical system according to the embodiment have a set shape, refractive power, focal length, and thickness, and therefore have improved distortion and aberration characteristics. As a result, the optical system and camera module according to the embodiment provide high-resolution images and high-quality images within a set angle of view.

[0013] In addition, the optical system and the camera module according to the embodiment operate in various temperature ranges. More specifically, the optical system includes a first lens made of glass, and second and third lenses made of plastic. In this case, the first lens, the second lens, and the third lens have a set refractive power. Thus, even if the focal length of the lens changes due to a change in the refractive power of the lens caused by a temperature change, the first lens, the second lens, and the third lens can mutually compensate for each other. That is, the optical system can effectively distribute the refractive power in a temperature range from low temperature (about -40°C) to high temperature (about 90°C). Also, it is possible to prevent the optical characteristics from changing in a temperature range from low temperature (about -40°C) to high temperature (about 90°C). Therefore, the optical system and the camera module according to the embodiment can maintain improved optical characteristics in various temperature ranges.

[0014] In addition, the optical system and the camera module according to the embodiment can satisfy the set angle of view with a minimum number of lenses, and have excellent optical characteristics. As a result, the optical system can have a slim and compact structure. Therefore, the optical system and the camera module can be provided for various applications and devices. In addition, the optical system and the camera module can have excellent optical characteristics even in a harsh temperature environment (for example, inside a vehicle at high temperatures in summer). [Brief description of the drawings]

[0015] [Figure 1] 1 is a plan view of a vehicle to which a camera module or optical system according to an embodiment is applied; [Diagram 2] 1 is a view illustrating the interior of a vehicle to which a camera module or optical system according to an embodiment is applied. [Diagram 3] 1 is a view illustrating the interior of a vehicle to which a camera module or optical system according to an embodiment is applied. [Figure 4] 1 is a table showing refractive index data of a first lens for light of various wavelengths over various temperature ranges in an optical system according to an embodiment. [Diagram 5] 11 is a graph showing a change in refractive index due to a change in temperature of a first lens in an optical system according to an example. [Figure 6] 1 is a table showing refractive index data of a second lens and a third lens for light of various wavelengths over various temperature ranges in an optical system according to an embodiment. [Figure 7] 11 is a graph showing the change in refractive index due to temperature change of the second lens and the third lens in the optical system according to the example. [Figure 8] FIG. 2 is a diagram illustrating the configuration of an optical system according to the first example. [Figure 9] 1 is a table for the first lens to the third lens of the optical system according to the first example. [Figure 10] 4 is a table showing the sag value of the first lens of the optical system according to the first example. [Figure 11] 4 is a table showing the thickness of the first lens in the optical system according to the first example. [Figure 12] 11 is a table showing the sag value of the second lens of the optical system according to the first example. [Figure 13] 4 is a table showing the thickness of the second lens in the optical system according to the first example. [Figure 14] 11 is a table showing the sag value of the third lens in the optical system according to the first example. [Figure 15] 11 is a table showing the thickness of a third lens in the optical system according to the first example. [Figure 16] 4 is a table showing aspheric coefficients of lenses in the optical system according to the first example. [Figure 17] 4 is a table showing the distance between lenses in the optical system according to the first embodiment. [Figure 18] 4 is a table showing the distance between lenses in the optical system according to the first embodiment. [Figure 19] 4 is a graph showing relative illumination for each field of the optical system according to the first embodiment; [Figure 20] 1 shows data on distortion characteristics of the optical system according to the first example. [Figure 21] 4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Figure 22] 4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Figure 23] 4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Figure 24] 4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Diagram 25] 4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Figure 26] 4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Figure 27] 4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Figure 28]4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Figure 29] 4 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the first example. [Diagram 30] FIG. 11 is a diagram illustrating the configuration of an optical system according to a second embodiment. [Diagram 31] 13 is a table for the first lens to the third lens of the optical system according to the second example. [Diagram 32] 13 is a table showing the sag value of the first lens of the optical system according to the second example. [Diagram 33] 13 is a table showing the thickness of the first lens in the optical system according to the second example. [Diagram 34] 13 is a table showing the sag value of the second lens of the optical system according to the second example. [Diagram 35] 13 is a table showing the thickness of the second lens in the optical system according to the second example. [Diagram 36] 13 is a table showing the sag value of the third lens of the optical system according to the second example. [Figure 37] 13 is a table showing the thickness of a third lens in the optical system according to the second example. [Figure 38] 13 is a table showing aspheric coefficients of lenses in the optical system according to the second embodiment. [Figure 39] 13 is a table showing the distance between lenses in the optical system according to the second embodiment. [Diagram 40] 13 is a table showing the distance between lenses in the optical system according to the second embodiment. [Diagram 41] 13 is a graph showing relative illumination for each field of the optical system according to the second embodiment; [Diagram 42] 13 shows data on distortion characteristics of the optical system according to the second embodiment. [Diagram 43] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Diagram 44] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Diagram 45]13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Diagram 46] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Figure 47] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Figure 48] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Figure 49] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Figure 50] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Figure 51] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the second example. [Figure 52] FIG. 11 is a diagram illustrating the configuration of an optical system according to a third example. [Figure 53] 13 is a table for the first lens to the third lens of the optical system according to the third example. [Figure 54] 13 is a table showing the sag value of the first lens of the optical system according to the third example. [Figure 55] 13 is a table showing the thickness of the first lens in the optical system according to the third example. [Figure 56] 13 is a table showing the sag value of the second lens of the optical system according to the third example. [Figure 57] 13 is a table showing the thickness of the second lens in the optical system according to the third example. [Figure 58] 13 is a table showing the sag value of the third lens of the optical system according to the third example. [Figure 59] 13 is a table showing the thickness of a third lens in the optical system according to the third example. [Figure 60] 13 is a table showing aspheric coefficients of lenses in an optical system according to a third embodiment. [Figure 61] 13 is a table showing the distance between lenses in the optical system according to the third embodiment. [Figure 62]13 is a table showing the distance between lenses in the optical system according to the third embodiment. [Figure 63] 13 is a graph showing relative illumination for each field of the optical system according to the third embodiment; [Figure 64] 13 shows data on distortion characteristics of the optical system according to the third example. [Figure 65] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 66] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 67] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 68] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 69] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 70] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 71] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 72] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 73] 13 is a graph showing the diffraction MTF and the degree of aberration for each temperature of the optical system according to the third example. [Figure 74] 13 is a table for the first lens to the third lens of the optical system according to the fourth example. [Figure 75] 1 is a graph showing the MTF characteristics at the center and periphery of the optical systems according to the first and fourth examples. [Figure 76] 1 is a graph showing the MTF characteristics at the center and periphery of the optical systems according to the first and fourth examples. [Figure 77] 1 is a graph showing the MTF characteristics at the center and periphery of the optical systems according to the first and fourth examples. [Figure 78] 1 is a graph showing the MTF characteristics at the center and periphery of the optical systems according to the first and fourth examples. [Figure 79] FIG. 2 is a configuration diagram for explaining some terms in the optical system according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0017] The technical concept of the present invention is not limited to the embodiments described herein, but may be embodied in various forms, and one or more of the components between the embodiments may be selectively combined or substituted within the scope of the technical concept of the present invention.

[0018] Furthermore, unless otherwise clearly and specifically stated, terms (including technical and scientific terms) used in the embodiments of the present invention shall be interpreted as having a meaning that is commonly understood by a person having ordinary knowledge in the technical field to which the present invention belongs, and commonly used terms, such as terms defined in a dictionary, shall be interpreted in consideration of the contextual meaning of the relevant technology.

[0019] In addition, the terms used in the examples of the present invention are intended to explain the examples and are not intended to limit the present invention. In this specification, the singular form can include the plural form unless otherwise specified, and when it is described as "A and (and) at least one (or more) of B and C," it can include one or more of all combinations that can be combined with A, B, and C.

[0020] In addition, in describing components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. are used. Such terms are used to distinguish the components from other components, and do not limit the nature or order of the components. Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it can include not only the case where the component is directly coupled or connected to the other component, but also the case where the component is "coupled," "coupled," or "connected" by a further component between the component and the other component.

[0021] In addition, when described as being formed or disposed "above or below" each component, "above or below" includes not only the case where two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. In addition, when described as "above or below," it can include not only the upper direction but also the lower direction based on one component.

[0022] A convex lens surface means that the lens surface in the optical axis region has a convex shape, and a concave lens surface means that the lens surface in the optical axis region has a concave shape.

[0023] Additionally, the "object side" refers to the surface of a lens that faces the object side relative to the optical axis, and the "sensor side" refers to the surface of a lens that faces the image sensor relative to the optical axis.

[0024] The vertical direction means a direction perpendicular to the optical axis, and the end of a lens or the end of a lens surface means the end of the effective area of ​​the lens through which incident light passes.

[0025] The center thickness of a lens means the length in the optical axis direction between the object side and the sensor side on the optical axis of the lens.

[0026] In addition, the effective diameter of the lens surface may have a measurement error of up to about ±0.4 mm depending on the measurement method. For example, the effective diameter is 2 mm or less, 1 mm or less, or 0.3 mm or less relative to the inner diameter of the flange portion.

[0027] In addition, in the embodiment, low temperature may refer to a specific temperature (-40°C), or may refer to a temperature range of about -40°C to about 30°C.

[0028] In addition, in the embodiments, room temperature may refer to a specific temperature (22°C), or may refer to a temperature range of about 20°C to about 30°C.

[0029] In addition, in the embodiments, high temperature may refer to a specific temperature (e.g., 90°C), or may refer to a temperature range of about 85°C to about 105°C.

[0030] Fig. 1 is a plan view of a vehicle to which a camera module or optical system according to an embodiment is applied, and Figs. 2 and 3 are views illustrating the interior of a vehicle to which a camera module or optical system according to an embodiment is applied.

[0031] 1, the vehicle camera system according to the embodiment includes an image generating unit 2110, a first information generating unit 2120, second information generating units 2210, 2220, 2230, 2240, 2250, 2260, and a control unit 2140.

[0032] The image generating unit 2110 includes at least one first camera module 2310 disposed outside or inside the vehicle 2000. The image generating unit 2110 generates a front image of the vehicle 2000. The image generating unit 2110 captures the front of the vehicle 2000 using the first camera module 2310. The image generating unit 2110 captures the surroundings of the vehicle 2000 in one or more directions. Thus, the image generating unit 2110 generates a surrounding image of the vehicle 2000. Here, the front image and the surrounding image may be digital images and may include color images, black and white images, or infrared images. The front image and the surrounding image may include still images and moving images. The image generating unit 2110 provides the front image and the surrounding image to the control unit 2140.

[0033] The first information generating unit 2120 includes at least one radar and / or camera disposed in the vehicle 2000. The first information generating unit 2120 senses the area ahead of the vehicle 2000 to generate the first sensing information. Specifically, the first information generating unit 2120 is disposed in the vehicle 2000. The first information generating unit 2120 may sense the position and speed of another vehicle located ahead of the vehicle 2000, and the presence and position of a pedestrian, to generate the first sensing information.

[0034] The first information generating unit 2120 controls the vehicle 2000 to maintain a constant distance from the vehicle in front using the first sensing information. Also, when the driver of the vehicle 2000 attempts to change the roadway on which the vehicle 2000 is traveling or when the vehicle is reversed into a parking space, the driving stability of the vehicle 2000 can be improved. The first information generating unit 2120 provides the first sensing information to the control unit 2140.

[0035] The second information generators 2210, 2220, 2230, 2240, 2250, and 2260 sense each side of the vehicle 2000 based on the forward image and the first sensing information. Thus, the second information generators 2210, 2220, 2230, 2240, 2250, and 2260 generate second sensing information. In detail, the second information generators 2210, 2220, 2230, 2240, 2250, and 2260 include at least one radar and / or camera disposed in the vehicle 2000. The second information generators 2210, 2220, 2230, 2240, 2250, and 2260 can sense the position and speed of a vehicle positioned on the side of the vehicle 2000 and capture an image. The second information generators 2210, 2220, 2230, 2240, 2250, and 2260 are disposed at the front corners, the side mirrors, the rear center, and the rear corners of the vehicle 2000, respectively.

[0036] 2 and 3, the image generating unit 2110 includes at least one second camera module 2320 disposed inside the vehicle 2000. The second camera module 2320 is disposed adjacent to the driver and passengers. For example, the second camera module 2320 is disposed at a position separated from the driver and passengers by a first distance d1, and may generate an image of the inside of the vehicle 2000. In this case, the first distance d1 may be about 500 mm or more. In particular, the first distance d1 may be about 600 mm or more. Also, the second camera module 2320 may have a field of view FOV of about 55 degrees or more.

[0037] The image generating unit 2110 may capture an image of the driver and / or passengers inside the vehicle 2000 using the second camera module 2320 to generate an internal image of the vehicle 2000. The internal image of the vehicle may be a digital image and may include a color image, a black and white image, an infrared image, etc. Also, the internal image may include a still image and a video. The image generating unit 2110 provides the internal image of the vehicle 2000 to the control unit 2140.

[0038] The control unit 2140 provides information to the passengers of the vehicle 2000 based on the information provided by the image generating unit 2110. For example, based on the information provided by the image generating unit 2110, the control unit 2140 can detect the driver's health condition, whether the driver is dozing, and whether the driver has drunk alcohol. Also, the control unit 2140 can provide guidance information or warning information to the driver. Also, based on the information provided by the image generating unit 2110, the control unit 2140 can detect whether the passenger is sleeping or the health condition. Also, the control unit 2140 can provide the driver and / or the passenger with information thereon.

[0039] Such a vehicle camera system includes a camera module including an optical system 1000 described below. The vehicle camera system provides information acquired through the front, rear, side or corner areas of the vehicle 2000 to a user. This protects the vehicle 2000 and objects from automatic driving or peripheral safety. The vehicle camera system is also disposed inside the vehicle 2000 to provide various information to the driver and passengers. That is, at least one of the first camera module 2310 and the second camera module 2320 may include the optical system 1000 described below.

[0040] A plurality of optical systems of the camera module according to the embodiments may be installed in a vehicle for safety regulations, enhancement of autonomous driving functions, and increased convenience. The optical system of the camera module is a component for controlling a lane keeping assistance system (LKAS), a lane departure warning system (LDWS), a driver monitoring system (DMS), etc., and is applied in a vehicle. The camera module according to the embodiments may realize stable optical performance even when the ambient temperature changes. In addition, the camera module according to the embodiments may provide a module with competitive price, thereby ensuring the reliability of vehicle parts.

[0041] The optical system according to the embodiment will be described in detail below.

[0042] The optical system 1000 according to the embodiment includes a plurality of lenses 100 and an image sensor 300. More specifically, the optical system 1000 according to the embodiment includes two or more lenses. For example, the optical system 1000 may include three lenses. The optical system 1000 includes a first lens 110, a second lens 120, a third lens 130, and an image sensor 300, which are sequentially arranged from the object side to the sensor side. The lenses 110, 120, and 130 are sequentially arranged along an optical axis OA of the optical system 1000.

[0043] Thus, light corresponding to information of an object passes through the first lens 110, the second lens 120 and the third lens 130 and enters the image sensor 300.

[0044] Each of the lenses 100 includes an effective area and a non-effective area. The effective area is defined as an area through which light incident on each of the lenses 110, 120, and 130 passes. That is, the effective area is an area where the incident light is refracted to realize optical characteristics.

[0045] The non-effective area is disposed around the effective area. The non-effective area is an area into which the light does not enter. In other words, the non-effective area is an area that is unrelated to the optical characteristics. The non-effective area is also an area that is fixed to a barrel (not shown) that houses the lens.

[0046] The image sensor 300 detects light. More specifically, the image sensor 300 detects light that passes through the lenses 100 in sequence. For example, the image sensor 300 may include a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS).

[0047] The image sensor 300 includes a plurality of pixels having a set size. For example, the pixel size of the image sensor 300 may be about 3 μm.

[0048] The image sensor 300 detects light of a set wavelength. For example, the image sensor 300 may detect infrared (IR) light. For example, the image sensor 300 may detect near infrared ray light of about 1500 nm or less. For example, the image sensor may detect light in a wavelength band of about 880 nm to about 1000 nm.

[0049] The optical system 1000 according to the embodiment further includes a cover glass 400 and a filter 500 .

[0050] The cover glass 400 is disposed between the plurality of lenses 100 and the image sensor 300. The cover glass 400 is disposed adjacent to the image sensor 300. The cover glass 400 has a shape corresponding to the image sensor 300. The cover glass 400 has a size larger than or equal to the image sensor 300. Thus, the cover glass 400 can protect the upper part of the image sensor 300.

[0051] In addition, the filter 500 is disposed between the plurality of lenses 100 and the image sensor 300. The filter 500 is disposed between the last lens (third lens 130) closest to the image sensor 300 and the image sensor 300. In detail, the filter 500 is disposed between the last lens (third lens 130) and the cover glass 400.

[0052] The filter 500 passes light in a set wavelength band and filters out light other than the set wavelength band. That is, the filter 500 passes light in a wavelength band corresponding to the light received by the image sensor 300. The filter 500 blocks light in a wavelength band not corresponding to the light received by the image sensor 300. In particular, the filter 500 passes light in an infrared wavelength band and blocks light in an ultraviolet and visible light bands. For example, the filter 500 may include at least one of an IR Pass filter and an IR Cut-off filter.

[0053] Moreover, the optical system 1000 according to the embodiment includes a diaphragm (not shown). The diaphragm adjusts the amount of light incident on the optical system 1000.

[0054] The aperture is disposed at a set position. For example, the aperture may be disposed in front of the first lens 110, or the aperture may be disposed between two of the lenses 110, 120, and 130. As an example, the aperture may be disposed behind the first lens 110.

[0055] Also, at least one of the lenses 110, 120, and 130 may function as an aperture. In particular, the object side or the sensor side of at least one of the lenses 110, 120, and 130 may function as an aperture. For example, the sensor side (second surface S2) of the first lens 110 may function as an aperture.

[0056] The lenses 100 according to the embodiment will be described in detail below.

[0057] The first lens 110 has a positive (+) refractive power on the optical axis OA and is made of a glass material.

[0058] The first lens 110 includes a first surface S1 defined as an object side surface and a second surface S2 defined as a sensor side surface. The first surface S1 may have a convex shape on the optical axis OA. The second surface S2 may have a concave shape on the optical axis OA, i.e., the first lens 110 has a meniscus shape that bulges toward the object side on the optical axis OA.

[0059] At least one of the first surface S1 and the second surface S2 is a spherical surface. For example, the first surface S1 and the second surface S2 may both be spherical surfaces.

[0060] The second lens 120 has a positive (+) refractive power on the optical axis OA. The material of the second lens 120 is different from the material of the first lens 110. As an example, the second lens 120 includes a plastic material.

[0061] The second lens 120 includes a third surface S3 defined as an object side surface and a fourth surface S4 defined as a sensor side surface. The third surface S3 may have a concave shape on the optical axis OA. The fourth surface S4 may have a convex shape on the optical axis OA. That is, the second lens 120 has a meniscus shape that bulges toward the sensor side on the optical axis OA.

[0062] At least one of the third surface S3 and the fourth surface S4 is an aspheric surface (Asphere). For example, both the third surface S3 and the fourth surface S4 may be aspheric surfaces (ASphere).

[0063] The third lens 130 has a positive (+) refractive power on the optical axis OA. The material of the third lens 130 is different from the material of the first lens 110. In addition, the material of the third lens 130 is the same as the material of the second lens 120. As an example, the third lens 130 may include a plastic material.

[0064] The third lens 130 includes a fifth surface S5 defined as an object side surface and a sixth surface S6 defined as a sensor side surface. The fifth surface S5 may have a convex shape on the optical axis OA. The sixth surface S6 may have a concave shape on the optical axis OA, i.e., the third lens 130 has a meniscus shape that bulges toward the object side on the optical axis OA.

[0065] At least one of the fifth surface S5 and the sixth surface S6 is an aspheric surface (Asphere). For example, both the fifth surface S5 and the sixth surface S6 may be aspheric surfaces (ASphere).

[0066] The optical system 1000 according to the embodiment satisfies at least one of the formulas described below. As a result, the optical system 1000 according to the embodiment can prevent the optical characteristics from changing due to temperature in a temperature range from low to high. Therefore, the optical system 1000 according to the embodiment has improved optical characteristics at various temperatures. In addition, the optical system 1000 according to the embodiment has improved distortion characteristics and aberration characteristics at various temperatures.

[0067] The following describes the formulas. Some terms used in the formulas will be explained with reference to FIG.

[0068] [Formula 1] 1.7≦nt_1≦2.3 (The nt_1 is the refractive index of the first lens 110 for light in the t-line (1013.98 nm) or d-line (587.6 nm) wavelength band.)

[0069] [Formula 2] nt_2 <nt_1 nt_3 <nt_1 (The nt_1 is the refractive index of the first lens 110 for light in the t-line or d-line wavelength band. The nt_2 is the refractive index of the second lens 120 for light in the t-line or d-line wavelength band. The nt_3 is the refractive index of the third lens 130 for light in the t-line or d-line wavelength band.)

[0070] [Formula 3] dnt_1 / dt≧0 dnt_2 / dt<0 dnt_3 / dt<0 |dnt_2 / dt| / |dnt_1 / dt|>20 (The dt means a temperature change amount (°C). The dnt_1 is a change in the refractive index of the first lens 110 in the entire wavelength band (particularly, the d-line wavelength band). That is, the dnt_1 / dt is a change in the refractive index of the first lens 110 depending on the temperature change amount in the entire wavelength band (particularly, the d-line wavelength band). The dnt_2 is a change in the refractive index of the second lens 120 in the entire wavelength band (particularly, the d-line wavelength band). The dnt_2 / dt is a change in the refractive index of the second lens 120 depending on the temperature change amount in the entire wavelength band (particularly, the d-line wavelength band). The dnt_3 is a change in the refractive index of the third lens 130 in the entire wavelength band (particularly, the d-line wavelength band). The dnt_3 / dt is a change in the refractive index of the third lens 130 depending on the temperature change amount in the entire wavelength band (particularly, the d-line wavelength band). The dt is a temperature change from -40°C to 90°C.

[0071] When the optical system 1000 according to the embodiment satisfies at least one of the formulas 1 to 3, the optical system 1000 has excellent optical performance in a temperature range from low to high.

[0072] [Formula 4] 1≦|v1-v2|≦10 1≦|v1-v3|≦10 50≦v1+v2+v3≦200 (The v1 is the Abbe number of the first lens 110. The v2 is the Abbe number of the second lens 120. The v3 is the Abbe number of the third lens 130.)

[0073] When the optical system 1000 according to the embodiment satisfies Equation 4, the optical system 1000 has excellent chromatic aberration characteristics.

[0074] Specifically, the formula 4 may satisfy 50≦v1+v2+v3≦150 for improved incident light control characteristics and aberration control characteristics in a set wavelength band. More specifically, the formula 4 may satisfy 50≦v1+v2+v3≦70 for improved incident light control characteristics and aberration control characteristics in a set wavelength band.

[0075] [Formula 5] 1mm≦TTL≦9mm (The TTL is the distance (mm) on the optical axis OA from the object side of the first lens 110 to the top surface of the image sensor 300 at room temperature (approximately 22° C.). Specifically, the formula 5 may be 2 mm≦TTL≦8 mm. More specifically, the formula 5 may be 3 mm≦TTL≦7 mm.

[0076] [Formula 6] |Diop_L1|>|Diop_L2|>|Diop_L3| (The Diop_L1 is a diopter value of the first lens 110 at room temperature (about 22° C.). The Diop_L2 is a diopter value of the second lens 120 at room temperature (about 22° C.). The Diop_L3 is a diopter value of the third lens 130 at room temperature (about 22° C.).)

[0077] [Formula 7] 1.5<|Diop_L1| / |Diop_L2|<2.5 (The Diop_L1 is a diopter value of the first lens 110 at room temperature (about 22° C.). The Diop_L2 is a diopter value of the second lens 120 at room temperature (about 22° C.).)

[0078] [Formula 8] 10 <Diop_L1 / Diop_L3<100 (The Diop_L1 is a diopter value of the first lens 110 at room temperature (about 22° C.). The Diop_L3 is a diopter value of the third lens 130 at room temperature (about 22° C.).)

[0079] When the optical system 1000 according to the embodiment satisfies at least one of the formulas 6 to 8, the lenses 100 of the optical system 1000 can have excellent optical performance in the center and periphery of the field of view (FOV). Also, the lenses 100 of the optical system 1000 can have excellent optical performance in a temperature range from low to high.

[0080] [Formula 9] 1.8≦F#≦2.2 (The F# is the F-number of the optical system 1000 at room temperature (approximately 22° C.), low temperature (approximately -40° C.), and high temperature (approximately 90° C.).

[0081] [Formula 10] 1mm≦D_1≦1.9mm (D_1 is the center thickness of the first lens 110 at room temperature (about 22° C.). That is, D_1 is the thickness (mm) of the first lens 110 at the optical axis OA.)

[0082] Specifically, the formula 10 may be 1.2 mm≦D_1≦1.8 mm. More specifically, the formula 10 may be 1.4 mm≦D_1≦1.7 mm.

[0083] When the optical system 1000 according to the embodiment satisfies Equation 10, the optical system 1000 has excellent optical performance and can be easily manufactured. For example, if the center thickness of the first lens 110 is less than about 1 mm, the focal length of the first lens 110 becomes long. Therefore, it becomes difficult to manufacture a glass lens. Also, if the center thickness of the first lens 110 exceeds about 1.9 mm, the focal length of the first lens 110 decreases. As a result, the optical performance of the optical system 1000 deteriorates.

[0084] [Formula 11] 0.15≦D_1 / TTL≦0.3 (The D_1 is the center thickness of the first lens 110 at room temperature (about 22° C.). That is, the D_1 is the thickness (mm) of the first lens 110 on the optical axis OA. The TTL is the distance (mm) from the object side of the first lens 110 to the top surface of the image sensor 300 on the optical axis OA at room temperature (about 22° C.).)

[0085] When the optical system 1000 according to the embodiment satisfies Equation 11, it is possible to prevent a change in optical performance due to a change from room temperature (about 22° C.) to high temperature (about 90° C.) In particular, Equation 11 can satisfy 0.20≦D_1 / TTL≦0.3 for excellent optical performance in various temperature ranges.

[0086] [Formula 12] 1 <D_1 / D_2<1.6 (The D_1 is the center thickness of the first lens 110 at room temperature (about 22° C.). That is, the D_1 is the thickness (mm) of the first lens 110 at the optical axis OA. The D_2 is the center thickness of the second lens 120 at room temperature (about 22° C.). That is, the D_2 is the thickness (mm) of the second lens 120 at the optical axis OA.)

[0087] When the optical system 1000 according to the embodiment satisfies Expression 12, the aberration characteristics of the optical system 1000 are improved.

[0088] [Formula 13] 2.2 <D_1 / D_3<3.0 (The D_1 is the center thickness of the first lens 110 at room temperature (about 22° C.). That is, the D_1 is the thickness (mm) of the first lens 110 at the optical axis OA. The D_3 is the center thickness of the third lens 130 at room temperature (about 22° C.). That is, the D_3 is the thickness (mm) of the third lens 130 at the optical axis OA.)

[0089] When the optical system 1000 according to the embodiment satisfies Expression 13, the aberration characteristics of the optical system 1000 are improved.

[0090] [Formula 14] |f1|<|f2|<|f3| (The f1 is the focal length (mm) of the first lens 110 at room temperature (about 22° C.). The f2 is the focal length (mm) of the second lens 120 at room temperature (about 22° C.). The f3 is the focal length (mm) of the third lens 130 at room temperature (about 22° C.).)

[0091] At room temperature (about 22° C.), the focal length (f1) of the first lens 110 may be greater than 4 mm and less than 7 mm. At room temperature (about 22° C.), the focal length (f2) of the second lens 120 may be greater than 7 mm and less than 13 mm. At room temperature (about 22° C.), the focal length (f3) of the third lens 130 may be greater than 200 mm and less than 300 mm.

[0092] When the optical system 1000 according to the embodiment satisfies Expression 14, the lenses 100 can have excellent optical performance in the center and periphery of the field of view (FOV).

[0093] [Formula 15] 0.3<|f1 / f2|<0.8 (The f1 is the focal length (mm) of the first lens 110 at room temperature (about 22° C.). The f2 is the focal length (mm) of the second lens 120 at room temperature (about 22° C.).)

[0094] When the optical system 1000 according to the embodiment satisfies Equation 15, the first lens 110 and the second lens 120 can have appropriate refractive power for controlling the path of the incident light, and thus the optical system 1000 can have improved resolving power.

[0095] [Formula 16] 10<|f3 / f1|<300 (The f1 is the focal length (mm) of the first lens 110 at room temperature (about 22° C.). The f3 is the focal length (mm) of the third lens 130 at room temperature (about 22° C.).)

[0096] When the optical system 1000 according to the embodiment satisfies Equation 16, the refractive powers of the first lens 110 and the third lens 130 are appropriately controlled, so that the optical system 1000 can have improved resolving power.

[0097] [Formula 17] 0.4<|L1R1| / |L1R2|<0.8 (The L1R1 is the radius of curvature of the object side surface of the first lens 110 at room temperature (about 22° C.). The L1R2 is the radius of curvature of the sensor side surface of the first lens 110 at room temperature (about 22° C.).)

[0098] When the optical system 1000 according to the embodiment satisfies Equation 17, the optical system 1000 can control the incident light and have improved aberration control characteristics.

[0099] [Formula 18] 1.0<|L2R1| / |L2R2|<2.0 (The L2R1 is the radius of curvature of the object side surface of the second lens 120 at room temperature (about 22° C.). The L2R2 is the radius of curvature of the sensor side surface of the second lens 120 at room temperature (about 22° C.).)

[0100] When the optical system 1000 according to the embodiment satisfies Equation 18, the optical system 1000 can have excellent aberration control characteristics.

[0101] [Formula 19] 1<|L3R1| / |L3R2|<1.3 (The L3R1 is the radius of curvature of the object side surface of the third lens 130 at room temperature (about 22° C.). The L3R2 is the radius of curvature of the sensor side surface of the third lens 130 at room temperature (about 22° C.).)

[0102] When the optical system 1000 according to the embodiment satisfies Expression 19, the optical system 1000 can have good optical performance in the peripheral part of the field of view (FOV).

[0103] [Formula 20] 0.5 <CA_L1S1 / CA_L3S2<1.0 (The CA_L1S1 is the size of the effective diameter (CA, Clear Aperture) of the object side of the first lens 110 at room temperature (about 22° C.). The CA_L3S2 is the size of the effective diameter of the sensor side of the third lens 130 at room temperature (about 22° C.).)

[0104] When the optical system 1000 according to the embodiment satisfies Expression 20, the optical system 1000 can control incident light. In addition, the optical system 1000 can have a slim and compact size while maintaining optical performance.

[0105] [Formula 21] CA_L1S2≦CA_L2S2≦CA_L3S2 CA_L1S2≦CA_L2S1≦CA_L3S1 CA_L1S2≦CA_L2S1≦CA_L2S2≦CA_L3S1≦CA_L3S2 (The CA_L1S2 is the effective diameter of the surface on which the diaphragm is disposed at room temperature (about 22° C.). That is, the CA_L1S2 is the effective diameter of the sensor side surface of the first lens 110. The CA_L2S1 is the effective diameter of the object side surface of the second lens 120 at room temperature (about 22° C.). The CA_L2S2 is the effective diameter of the object side surface of the second lens 120 at room temperature (about 22° C.). The L3S1 is the effective diameter of the object side surface of the third lens 130 at room temperature (about 22° C.). The CA_L3S2 is the effective diameter of the sensor side surface of the third lens 130 at room temperature (about 22° C.).

[0106] When the optical system 1000 according to the embodiment satisfies Expression 21, the optical system 1000 can control incident light. In addition, the optical system 1000 can have a slim and compact size while maintaining optical performance.

[0107] [Formula 22] 0.4 <d12 / D_1<0.9 (The d12 is the distance (mm) between the first lens 110 and the second lens 120 on the optical axis OA at room temperature (about 22° C.). The D_1 is the center thickness of the first lens 110 at room temperature (about 22° C.). That is, D_1 is the thickness (mm) of the first lens 110 on the optical axis OA.)

[0108] When the optical system 1000 according to the embodiment satisfies Equation 22, the optical system 1000 can control incident light and has excellent aberration control characteristics.

[0109] [Formula 23] 0.2≦CA_Smax / ImgH≦0.7 (The CA_Smax is the effective diameter (CA) of the lens surface having the largest effective diameter (CA) among the lens surfaces of the plurality of lenses 100 at room temperature (approximately 22° C.). In addition, the center of the upper surface of the image sensor 300 overlapping with the optical axis OA at room temperature (approximately 22° C.) may be defined as a 0 field area. The ImgH means twice the vertical distance of the optical axis OA from the 0 field area to the 1.0 field area. In other words, the ImgH means the overall diagonal length (mm) of the image sensor 300 at room temperature (approximately 22° C.).)

[0110] When the optical system 1000 according to the embodiment satisfies Expression 23, the optical system 1000 has excellent optical performance in the center and periphery of the field of view (FOV), and can have a slim and compact size.

[0111] [Formula 24] 3≦EFL≦5 (The EFL (Effective Focal Length) refers to the effective focal length (mm) of the optical system 1000 at room temperature (about 22° C.).)

[0112] [Formula 25] 40 degrees ≦ FOV ≦ 50 degrees (The FOV refers to the field of view (FOV) of the optical system 1000 at room temperature (about 22° C.), low temperature (about -40° C.), and high temperature (about 90° C.).

[0113] [Formula 26] 1.2 <TTL / ImgH<1.6 (The TTL is the distance (mm) on the optical axis OA from the object side of the first lens 110 to the top surface of the image sensor 300 at room temperature (about 22° C.). Also, the center of the top surface of the image sensor 300 that overlaps with the optical axis OA at room temperature (about 22° C.) can be defined as a 0 field area. The ImgH means twice the vertical distance of the optical axis OA from the 0 field area to the 1.0 field area. That is, the ImgH means the entire diagonal length (mm) of the image sensor 300 at room temperature (about 22° C.).)

[0114] When the optical system 1000 according to the embodiment satisfies Equation 26, the optical system 1000 can secure a back focal length (BFL) for a large image sensor 300. For example, a back focal length (BFL) for a large image sensor 300 of about 1 inch can be secured, and a small TTL can be provided. Therefore, high image quality and a slim structure can be provided.

[0115] [Formula 27] 0.2 <BFL / ImgH<0.5 (The BFL (Back focal length) is the distance (mm) on the optical axis OA from the apex of the sensor side of the lens closest to the image sensor 300 to the top surface of the image sensor 300 at room temperature (about 22° C.). In addition, the center of the top surface of the image sensor 300 overlapping with the optical axis OA at room temperature (about 22° C.) can be defined as the 0 field area. The ImgH means twice the vertical distance of the optical axis OA from the 0 field area to the 1.0 field area. In other words, the ImgH means the overall diagonal length (mm) of the image sensor 300 at room temperature (about 22° C.).)

[0116] When the optical system 1000 according to the embodiment satisfies Equation 27, the optical system 1000 can secure a back focal length (BFL) for a large image sensor 300. For example, a back focal length (BFL) for a large image sensor 300 of about 1 inch can be secured. In addition, the distance between the last lens and the image sensor 300 can be minimized. Therefore, excellent optical characteristics can be obtained at the center and periphery of the field of view (FOV).

[0117] [Formula 28] 3 <TTL / BFL<5 (The TTL is the distance (mm) on the optical axis OA from the object side of the first lens 110 to the top surface of the image sensor 300 at room temperature (about 22° C.). The BFL (Back focal length) is the distance (mm) on the optical axis OA from the apex of the sensor side of the lens closest to the image sensor 300 to the top surface of the image sensor 300 at room temperature (about 22° C.).)

[0118] When the optical system 1000 according to the embodiment satisfies Expression 28, the optical system 1000 can ensure the BFL and have a slim and compact size.

[0119] [Formula 29] 0.4 <EFL / TTL<0.8 (The EFL (Effective Focal Length) means the effective focal length (mm) of the optical system 1000 at room temperature (about 22° C.). The TTL means the distance (mm) on the optical axis OA from the object side surface (first surface S1) of the first lens 110 to the upper surface of the image sensor 300 at room temperature (about 22° C.).)

[0120] When the optical system 1000 according to the embodiment satisfies Equation 29, the optical system 1000 can have a slim and compact size.

[0121] [Formula 30] 2 <EFL / BFL<3 (The EFL (Effective Focal Length) refers to the effective focal length (mm) of the optical system 1000 at room temperature (about 22° C.). The BFL (Back focal length) refers to the distance (mm) on the optical axis OA from the apex of the sensor side of the lens closest to the image sensor 300 to the top surface of the image sensor 300 at room temperature (about 22° C.).)

[0122] When the optical system 1000 according to the embodiment satisfies Equation 30, the optical system 1000 can have a set angle of view and an appropriate focal length. In addition, the optical system 1000 can have a slim and compact size. In addition, the optical system 1000 can minimize the distance between the last lens and the image sensor 300. Therefore, the optical system 1000 can have excellent optical characteristics in the peripheral part of the field of view (FOV).

[0123] [Formula 31] 0.7 <EFL / ImgH<1.2 (The EFL (Effective Focal Length) refers to the effective focal length (mm) of the optical system 1000 at room temperature (approximately 22° C.). Also, the center of the top surface of the image sensor 300 that overlaps with the optical axis OA at room temperature (approximately 22° C.) can be defined as a 0 field area. The ImgH refers to twice the vertical distance of the optical axis OA from the 0 field area to the 1.0 field area. In other words, the ImgH refers to the entire diagonal length (mm) of the image sensor 300 at room temperature (approximately 22° C.).)

[0124] When the optical system 1000 according to the embodiment satisfies Equation 31, the optical system 1000 can be applied to a large-sized image sensor 300. For example, a large image sensor 300 of about 1 inch can be applied, and the optical system 1000 can have improved aberration characteristics.

[0125] [Formula 32] 0.2 < D_1_ET / D_1 < 1.7 (The D_1 is the central thickness of the first lens 110 at normal temperature (about 22°C). That is, the D_1 is the thickness (mm) on the optical axis OA of the first lens 110. The D_1_ET is the thickness (mm) in the direction of the optical axis OA at the end of the effective region of the first lens 110 at normal temperature (about 22°C). The D_1_ET is the distance (mm) in the direction of the optical axis OA between the end of the effective region on the object side surface of the first lens 110 and the end of the effective region on the sensor side surface of the first lens 110. The D_1_ET may be the thickness of the flange portion outside the effective diameter of the first lens 110.)

[0126] When the optical system 1000 according to the embodiment satisfies the mathematical formula 32, the optical system 1000 can control the incident light. Also, it can have excellent aberration control characteristics in a temperature range from low to high temperature.)

[0127] Specifically, the mathematical formula 32 can satisfy 0.4 < D_1_ET / D_1 < 1.5 for excellent incident light control characteristics and aberration control characteristics in a temperature range from low to high temperature. More specifically, the mathematical formula 32 can satisfy 0.6 < D_1_ET / D_1 < 1.0 for excellent incident light control characteristics and aberration control characteristics in a temperature range from low to high temperature.)

[0128] [Mathematical formula 33] 0.3 < D_2_ET / D_2 < 1.7 (The D_2 is the central thickness of the second lens 120 at normal temperature (about 22°C). That is, the D_2 is the thickness (mm) on the optical axis OA of the second lens 120. The D_2_ET is the thickness (mm) in the direction of the optical axis OA at the end of the effective region of the second lens 120 at normal temperature (about 22°C). The D_2_ET is the distance (mm) in the direction of the optical axis OA between the end of the effective region on the object side surface of the second lens 120 and the end of the effective region on the sensor side surface of the second lens 120. The D_2_ET may be the thickness of the flange portion outside the effective diameter of the second lens 120.)

[0129] When the optical system 1000 according to the embodiment satisfies Equation 33, the optical system 1000 can have excellent chromatic aberration control characteristics in a temperature range from low temperature to high temperature.

[0130] Specifically, Equation 33 can satisfy 0.4 < D_2_ET / D_2 < 1.5 for excellent chromatic aberration control characteristics in a temperature range from low temperature to high temperature. More specifically, Equation 33 can satisfy 0.5 ≤ D_2_ET / D_2 ≤ 1.0 for excellent chromatic aberration control characteristics in a temperature range from low temperature to high temperature.

[0131] [Equation 34] 0.3 < D_3_ET / D_3 < 1.7 (The D_3 is the central thickness of the third lens 130 at room temperature (about 22°C). That is, the D_3 is the thickness (mm) on the optical axis OA of the third lens 130. The D_3_ET means the thickness (mm) in the direction of the optical axis OA at the end of the effective region of the third lens 130 at room temperature (about 22°C). D_3_ET means the distance (mm) in the direction of the optical axis OA between the end of the effective region on the object side surface of the third lens 130 and the end of the effective region on the sensor side surface of the third lens 130. The D_3_ET may be the thickness of the flange portion outside the effective diameter of the third lens 130.)

[0132] When the optical system 1000 according to the embodiment satisfies Equation 34, the optical system 1000 can have improved distortion control characteristics in a temperature range from low temperature to high temperature. Also, it can have excellent optical performance at the peripheral portion of the field of view (FOV).

[0133] Specifically, Equation 34 can satisfy 0.5 < D_3_ET / D_3 < 1.6 for excellent distortion control characteristics in various temperature ranges. More specifically, Equation 34 can satisfy 1.0 < D_3_ET / D_3 < 1.5 for excellent distortion control characteristics in various temperature ranges.

[0134] [Equation 35] 0.1 < d23 / d23_max < 1 The d23 is the distance (mm) on the optical axis OA between the second lens 120 and the third lens 130 at room temperature (about 22°C). The d23_max is the maximum distance (mm) in the direction of the optical axis OA between the sensor side surface of the second lens 120 and the object side surface of the third lens 130 at room temperature (about 22°C).

[0135] When the optical system 1000 according to the embodiment satisfies Equation 35, the optical system 1000 can improve the chromatic aberration and distortion aberration characteristics of the peripheral portion of the angle of view (FOV) in the low to high temperature range.

[0136] Specifically, Equation 35 can satisfy 0.2 < d23 / d23_max < 0.9 to improve the optical performance of the peripheral portion of the angle of view (FOV) in various temperature ranges. More specifically, Equation 35 can satisfy 0.25 < d23 / d23_max < 0.8 to improve the optical performance of the peripheral portion of the angle of view (FOV) in various temperature ranges.

[0137] [Equation 36] 1 < d23_Sag_L3S1_max / d23 < 5 The d23 is the distance (mm) on the optical axis OA between the second lens 120 and the third lens 130 at room temperature (about 22°C). Also, the second lens 120 includes the maximum Sag of the object side surface of the third lens 130 and the sensor side surface facing in the direction of the optical axis OA. The d23_Sag_L3S1_max is the distance (mm) in the direction of the optical axis OA from the maximum Sag of the object side surface of the third lens 130 to the facing sensor side surface.

[0138] When the optical system 1000 according to the embodiment satisfies Equation 36, the optical system 1000 can improve the optical performance of the peripheral portion of the angle of view (FOV) in the low to high temperature range.

[0139] Specifically, the formula 36 can satisfy 1.3 < d23_Sag_L3S1_max / d23 < 4 to improve the optical performance of the peripheral part of the angle of view (FOV) in various temperature ranges. More specifically, the formula 36 can satisfy 1.5 < d23_Sag_L3S1_max / d23 < 3 to improve the optical performance of the peripheral part of the angle of view (FOV) in various temperature ranges.

[0140] [Formula 37] 0.2 < L_Sag_L3S1 / CA_L3S1 < 0.8 (The L_Sag_L3S1 is the distance in the direction perpendicular to the optical axis OA from the optical axis OA to the maximum |Sag| of the object side surface of the third lens 130 at room temperature (about 22°C). The CA_L3S1 means the size of the effective diameter of the object side surface of the third lens 130 at room temperature (about 22°C).

[0141] When the optical system 1000 according to the embodiment satisfies the formula 37, the optical system 1000 can improve the peripheral optical performance of the angle of view (FOV) in the temperature range from low temperature to high temperature.

[0142] Specifically, the formula 37 can satisfy 0.3 < L_Sag_L3S1 / CA_L3S1 < 0.7 to improve the optical performance of the peripheral part of the angle of view (FOV) in various temperature ranges. More specifically, the formula 37 can satisfy 0.4 < L_Sag_L3S1 / CA_L3S1 < 0.5 to further improve the optical performance of the peripheral part of the angle of view (FOV) in various temperature ranges.

[0143] [Formula 38] 0.5 < |Sag_L3S1_max| < 1.5 (The Sag_L3S1_max is the difference between the Sag of the object side surface of the third lens 130 on the optical axis OA and the maximum Sag of the object side surface of the third lens 130 at room temperature (about 22°C).

[0144] When the optical system 1000 according to the embodiment satisfies the formula 38, the optical system 1000 can improve the peripheral optical performance of the angle of view (FOV) in the temperature range from low temperature to high temperature.

[0145] Specifically, the formula 38 can satisfy 0.7 < |Sag_L3S1_max| < 1.3 to improve the optical performance of the peripheral part of the field of view (FOV) in various temperature ranges. More specifically, the formula 38 can satisfy 0.9 < |Sag_L3S1_max| < 1.1 to improve the optical performance of the peripheral part of the field of view (FOV) in various temperature ranges.

[0146] [Formula 39] 0.1 < L_Sag_L3S2 / CA_L3S2 < 1.2 (The L_Sag_L3S2 is the distance in the direction perpendicular to the optical axis OA from the optical axis OA to the maximum Sag of the sensor side surface of the third lens 130 at room temperature (about 22°C). The CA_L3S2 is the size of the effective diameter of the sensor side surface of the third lens 130 at room temperature (about 22°C).)

[0147] Specifically, the formula 39 can satisfy 0.3 < L_Sag_L3S2 / CA_L3S2 < 1.0 to improve the optical performance of the peripheral part of the field of view (FOV) in various temperature ranges. More specifically, the formula 39 can satisfy 0.5 < L_Sag_L3S2 / CA_L3S2 < 0.8 to improve the optical performance of the peripheral part of the field of view (FOV) in various temperature ranges.

[0148] When the optical system 1000 according to the embodiment satisfies at least one of the formula 38 and the formula 39, the optical system 1000 can improve the chromatic aberration and aberration characteristics in the temperature range from low temperature to high temperature. Also, it can have excellent optical performance not only at the center part of the field of view (FOV) but also at the peripheral part.

[0149] [Formula 40] 0.1 < |Sag_L3S2_max| < 0.4 (The |Sag_L3S2_max| is the difference between the Sag of the sensor side surface of the third lens 130 on the optical axis OA and the maximum Sag of the sensor side surface of the third lens 130 at room temperature (about 22°C).)

[0150] When the optical system 1000 according to the embodiment satisfies Equation 40, the optical system 1000 can improve the peripheral optical performance of the angle of view (FOV) in a temperature range from low to high temperature.

[0151] Specifically, Equation 40 can satisfy 0.15 < |Sag_L3S2_max| < 0.35 in order to improve the optical performance of the peripheral part of the angle of view (FOV) in various temperature ranges. More specifically, Equation 40 can satisfy 0.2 < |Sag_L3S2_max| < 0.3 in order to improve the optical performance of the peripheral part of the angle of view (FOV) in various temperature ranges.

[0152] [Equation 41] 0.2 < L3S2_max_sag to Sensor / BFL < 1 (The BFL (Back focal length) is the distance (mm) on the optical axis OA from the vertex of the sensor side surface of the lens closest to the image sensor 300 to the upper surface of the image sensor 300. The L3S2_max_sag to Sensor is the distance (mm) in the direction of the optical axis OA from the maximum Sag of the sensor side surface of the third lens 130 to the image sensor 300 at room temperature (about 22°C).

[0153] When the optical system 1000 according to the embodiment satisfies Equation 41, the distortion aberration characteristics of the optical system 1000 are improved. Also, it can have excellent optical performance at the peripheral part of the angle of view (FOV). Also, the assembly becomes easy.

[0154] Specifically, Equation 41 can satisfy 0.3 < L3S2_max_sag to Sensor / BFL < 0.95 in order to have excellent characteristics in various temperature ranges. More specifically, Equation 41 can satisfy 0.4 < L3S2_max_sag to Sensor / BFL < 0.9 in order to have excellent characteristics in various temperature ranges.

[0155] [Equation 42] 3 < ΣIndex < 10 (The ΣIndex is the sum of the refractive indices at the d-lines of the lenses 110, 120, and 130 at room temperature (about 22° C.).)

[0156] When the optical system 1000 according to the embodiment satisfies Equation 42, the TTL of the optical system 1000 can be controlled in a low to high temperature range, and the optical system 1000 can have improved chromatic aberration and resolution.

[0157] [Formula 43] 10<ΣAbb / ΣIndex<50 (The ΣIndex is the sum of the refractive indices at the d-lines of the lenses 110, 120, and 130 at room temperature (about 22° C.). The ΣAbb is the sum of the Abbe's numbers of the lenses 110, 120, and 130 at room temperature (about 22° C.).)

[0158] When the optical system 1000 according to the embodiment satisfies Equation 43, the optical system 1000 can have improved aberration characteristics and resolving power in the low to high temperature range.

[0159] [Formula 44] 1 <CA_Smax / CA_Smin<3 (The CA_Smax is the effective diameter (CA) of the lens surface having the largest effective diameter (CA) at room temperature (about 22° C.) among the lens surfaces of the plurality of lenses 100. The CA_Smin is the effective diameter (CA) of the lens surface having the smallest effective diameter (CA) at room temperature (about 22° C.) among the lens surfaces of the plurality of lenses 100.)

[0160] When the optical system 1000 according to the embodiment satisfies Equation 44, the optical system 1000 can have a slim and compact size, and thus can have an appropriate size for excellent optical performance in a low to high temperature range.

[0161] [Formula 45] 1 <CA_Smax / CA_Aver<3 (The CA_Smax is the effective diameter (CA) of the lens surface having the largest effective diameter (CA) at room temperature (about 22° C.) among the lens surfaces of the plurality of lenses 100. The CA_Aver is the average (mm) of the effective diameters (CA) of the lens surfaces (object side and sensor side) of the plurality of lenses 100 at room temperature (about 22° C.).)

[0162] When the optical system 1000 according to the embodiment satisfies Equation 45, the optical system 1000 can have a slim and compact size, and thus can have an appropriate size for excellent optical performance in a low to high temperature range.

[0163] [Formula 46] 0.1 <CA_Smin / CA_Aver<1 (The CA_Smin is the effective diameter (CA) of the lens surface having the smallest effective diameter (CA) at room temperature (approximately 22° C.) among the lens surfaces of the plurality of lenses 100. The CA_Aver is the average (mm) of the effective diameters (CA) of the lens surfaces (object side and sensor side) of the plurality of lenses 100 at room temperature (approximately 22° C.).)

[0164] When the optical system 1000 according to the embodiment satisfies Equation 46, the optical system 1000 can have a slim and compact size, and thus can have an appropriate size for excellent optical performance in a low to high temperature range.

[0165] [Formula 47] 0.1 <CA_Smax / ImgH<1 (The CA_Smax is the effective diameter (CA) of the lens surface having the largest effective diameter (CA) among the lens surfaces of the plurality of lenses 100 at room temperature (about 22° C.). In addition, the center of the top surface of the image sensor 300 overlapping with the optical axis OA at room temperature (about 22° C.) may be defined as the 0 field area. The ImgH means twice the vertical distance of the optical axis OA from the 0 field area to the 1.0 field area. In other words, the ImgH means the overall diagonal length (mm) of the image sensor 300 at room temperature (about 22° C.).

[0166] When the optical system 1000 according to the embodiment satisfies Expression 47, the optical system 1000 has excellent optical performance in the center and periphery of the field of view (FOV) in a low to high temperature range. In addition, the optical system 1000 can have a slim and compact size.

[0167] [Formula 48] 0.5 <CA_L1S2 / CA_L2S1<1 (The CA_L1S2 represents the effective diameter (mm) of the first lens 110 on the sensor side at room temperature (about 22° C.). The CA_L2S1 represents the effective diameter (mm) of the second lens 120 on the object side at room temperature (about 22° C.).

[0168] When the optical system 1000 according to the embodiment satisfies Equation 48, the optical system 1000 has improved chromatic aberration control characteristics in the low to high temperature range.

[0169] [Formula 49]

number

[0170] [Formula 50] 0 <d1Ap<0.2 (The d1Ap is the distance (mm) in the optical axis OA direction from the end of the effective diameter of the sensor side (second surface S2) of the first lens 110 to the aperture 600 at room temperature (approximately 22° C.).

[0171] [Formula 51] 0.8 <CA_L1S2 / CA_Ap<1.8 (The CA_L1S2 is the effective diameter (mm) of the first lens 110 on the sensor side at room temperature (about 22° C.). The CA_Ap is the effective diameter (mm) of the aperture 600 at room temperature (about 22° C.).)

[0172] When the optical system 1000 according to the embodiment satisfies Expressions 50 and 51, the optical system 1000 can control incident light and has improved aberration control characteristics.

[0173] [Formula 52] 0.95≦EFL_R / EFL_H≦1.05 (The EFL_R is the effective focal length (mm) of the optical system 1000 at room temperature (about 22° C.). The EFL_H is the effective focal length (mm) of the optical system 1000 at high temperature (about 90° C.).

[0174] [Formula 53] 0.95≦EFL_R / EFL_L≦1.05 (The EFL_R is the effective focal length (mm) of the optical system 1000 at room temperature (approximately 22° C.). The EFL_L is the effective focal length (mm) of the optical system 1000 at low temperature (approximately −40° C.).)

[0175] [Formula 54] 0.95≦FOV_R / FOV_H≦1.05 (The FOV_R is the angle of view (°) of the optical system 1000 at room temperature (approximately 22° C.). The FOV_H is the angle of view (°) of the optical system 1000 at a high temperature (approximately 90° C.).

[0176] [Formula 55] 0.95≦FOV_R / FOV_L≦1.05 (The FOV_R is the angle of view (°) of the optical system 1000 at room temperature (approximately 22° C.). The FOV_L is the angle of view (°) of the optical system 1000 at a low temperature (approximately 90° C.).)

[0177] When the optical system 1000 according to the embodiment satisfies Equations 52 to 55, the optical system 1000 can have excellent optical performance in a low to high temperature range. In addition, the chief ray angle (CRA) of the optical system 1000 according to the embodiment can have about 20 degrees to about 30 degrees. In particular, the chief ray angle (CRA) of the optical system 1000 can have about 24 degrees to about 26 degrees at 1.0 field. In addition, the optical distortion of the optical system 1000 can be ±4% or less at 1.0 field.

[0178] In particular, in the optical system 1000 according to the embodiment, the first lens 110 may include a different material from the second lens 120 and the third lens 130. For example, the first lens 110 may be made of a glass material, and the second lens 120 and the third lens 130 may be made of the same plastic material.

[0179] 4 shows data on the refractive index of the first lens 110 for light of various wavelengths in a temperature range from low (−40° C.) to high (90° C.) Fig. 5 shows a graph showing the change in the refractive index of the first lens 110 according to the change in temperature.

[0180] 6 shows data on the refractive index of the second lens 120 and the third lens 130 for light of various wavelengths in a temperature range from low (−40° C.) to high (90° C.) Fig. 7 shows a graph showing the change in the refractive index of the second lens 120 and the third lens 130 according to the change in temperature.

[0181] 4 to 7, the first lens 110, the second lens 120, and the third lens 130 have different refractive index change characteristics according to a change in temperature.

[0182] 4 and 5, the first lens 110 has a very small refractive index change according to temperature in the temperature range from low temperature (about -40°C) to high temperature (about 90°C). In particular, the refractive index change (dnt_1 / dt) of the first lens 110 according to temperature change is a positive number as shown in Equation 3. As shown in FIG. 5, it has a positive slope.

[0183] 6 and 7, the second lens 120 and the third lens 130 have a large refractive index that changes according to temperature in a temperature range from low temperature (about -40°C) to high temperature (about 90°C). In particular, the refractive index changes (dnt_2 / dt, dnt_3 / dt) of the second lens 120 and the third lens 130 according to temperature change are negative as shown in Equation 3. Also, as shown in FIG. 7, they have a negative slope.

[0184] The first lens 110 has a refractive index greater than those of the second lens 120 and the third lens 130. In particular, the first lens 110 has a refractive index greater than those of the second lens 120 and the third lens 130 in order to compensate for the second lens 120 and the third lens 130, whose refractive indexes change greatly according to temperature changes.

[0185] Also, the first lens 110 has a larger diopter value than the second lens 120 and the third lens 130 to compensate for the second lens 120 and the third lens 130. Thus, the first lens 110 can effectively distribute the refractive index of the optical system 1000 in a temperature range from low temperature (about -40°C) to high temperature (about 90°C). Therefore, the optical system 1000 according to the embodiment can have improved optical performance in various temperature ranges.

[0186] That is, the first lens 110 has a different material from the second lens 120 and the third lens 130. Also, the optical system 1000 satisfies at least one of Equations 1 to 55. Thus, the optical system 1000 can prevent optical characteristics from changing due to temperature. Also, the optical system 1000 has improved optical characteristics in various temperature ranges.

[0187] In addition, the optical system 1000 according to the embodiment satisfies at least one of the formulas 1 to 55. Therefore, it is possible to prevent the distortion and aberration characteristics from changing in various temperature ranges, and therefore it is possible to have improved optical characteristics.

[0188] Furthermore, the intervals between the lenses 100 have values ​​that are set according to the region.

[0189] The first lens 110 and the second lens 120 are spaced apart by a first distance. The first distance is a distance between the first lens 110 and the second lens 120 in the optical axis OA direction.

[0190] The first distance varies depending on the position between the first lens 110 and the second lens 120. In more detail, when the optical axis OA is defined as a start point and the end point of the effective area of ​​the sensor side of the first lens 110 is defined as an end point, the first distance varies while being extended from the optical axis OA in a direction perpendicular to the optical axis OA. That is, the first distance varies while being extended from the optical axis OA to the end of the effective diameter of the second surface S2.

[0191] The first distance decreases from the optical axis OA to a first point L1 located on the second surface S2, where the first point L1 is an end of an effective area of ​​the second surface S2.

[0192] The first distance has a maximum value at the optical axis OA. The first distance has a minimum value at the first point L1. The maximum value of the first distance may be about 1.1 times or more the minimum value. More specifically, the maximum value of the first distance may be about 1.1 to about 3 times the minimum value.

[0193] The second lens 120 and the third lens 130 are spaced apart by a second distance. The second distance is the distance between the second lens 120 and the third lens 130 in the optical axis OA direction.

[0194] The second distance varies depending on the position between the second lens 120 and the third lens 130. In more detail, when the optical axis OA is taken as a starting point and the end of the effective area of ​​the sensor side of the second lens 120 is taken as an end point, the second distance varies while extending from the optical axis OA in a direction perpendicular to the optical axis OA. That is, the second distance varies while extending from the optical axis OA to the end of the effective diameter of the fourth surface S4.

[0195] The second distance increases as it extends from the optical axis OA to a second point L2 located on the fourth surface S4, where the second point L2 is an end of an effective area of ​​the fourth surface S4.

[0196] The second distance has a maximum value at the second point L2. Also, the second distance has a minimum value at the optical axis OA. In this case, the maximum value of the second distance may be about twice or more the minimum value. More specifically, the maximum value of the second distance may be about two to four times the minimum value.

[0197] As a result, the optical system 1000 has improved optical characteristics. In particular, the interval between the first lens 110 and the second lens 120 and the interval between the second lens 120 and the third lens 130 are set according to the positions. Therefore, the optical system 1000 can prevent the optical characteristics from changing in a temperature range from low to high. Therefore, the optical system and camera module according to the embodiment can maintain improved optical characteristics in various temperature ranges.

[0198] The optical system 1000 according to the first embodiment will be described in detail with reference to FIGS.

[0199] 8 to 29, the optical system 1000 according to the first embodiment includes a first lens 110, a second lens 120, a third lens 130, and an image sensor 300, which are sequentially arranged from the object side to the sensor side. The lenses 110, 120, and 130 are sequentially arranged along the optical axis OA of the optical system 1000.

[0200] In addition, between the sensor side surface (second surface S2) of the first lens 110 and the object side surface (third surface S3) of the second lens 120, a diaphragm 600 is disposed.

[0201] In detail, the aperture 600 is between the sensor side (second surface S2) of the first lens 110 and the object side (third surface S3) of the second lens 120 and is spaced apart from the sensor side (second surface S2) of the first lens 110.

[0202] For example, the aperture 600 may be spaced apart from the sensor side (second surface S2) of the first lens 110 as shown in Equations 50 and 51.

[0203] In addition, a filter 500 is disposed between the lenses 100 and the image sensor 300. A cover glass 400 is disposed between the filter 500 and the image sensor 300.

[0204] 9 shows data on the radius of curvature of the lenses 110, 120, and 130 according to the first embodiment, the thickness of each lens on the optical axis OA, the distance between each lens on the optical axis OA, the refractive index for light in the t-line (1013.98 nm) wavelength band, the Abbe's number, the clear aperture (CA), and the focal length. In particular, the data shown in FIG. 9 is for room temperature (approximately 22° C.).

[0205] 8 and 9, the first lens 110 is made of a glass material. The first lens 110 has a positive (+) refractive power on the optical axis OA. The first surface S1 of the first lens 110 may have a convex shape on the optical axis OA. The second surface S2 may have a concave shape on the optical axis OA. The first lens 110 may have a meniscus shape that bulges toward the object side on the optical axis OA. The first surface S1 may be a spherical surface, and the second surface S2 may be a spherical surface.

[0206] FIG. 10 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of the object side surface (first surface S1) and the sensor side surface (second surface S2) of the first lens 110 at room temperature (about 22° C.).

[0207] Also, Fig. 11 shows data on lens thickness according to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_1 in Fig. 11 is the central thickness of the first lens 110. That is, D_1 is the thickness (mm) of the first lens 110 at the optical axis OA. Also, D_1_ET in Fig. 11 is the thickness (mm) of the first lens 110 in the optical axis OA direction at the end of the effective area. More specifically, D_1_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (first surface S1) of the first lens 110 and the end of the effective area of ​​the sensor side surface (second surface S2) of the first lens 110.

[0208] 9 to 11, the thickness of the first lens 110 in the direction of the optical axis OA increases as the first lens 110 extends from the optical axis OA toward the end of the effective diameter of the first lens 110. In the direction of the optical axis OA, as shown in FIG.

[0209] Therefore, the first lens 110 can have improved aberration control characteristics by controlling incident light.

[0210] The second lens 120 is made of a plastic material. The second lens 120 has a positive (+) refractive power on the optical axis OA. The third surface S3 of the second lens 120 may have a concave shape on the optical axis OA, and the fourth surface S4 may have a convex shape on the optical axis OA. The second lens 120 may have a meniscus shape that bulges toward the sensor on the optical axis OA. The third surface S3 may be an aspheric surface (Asphere), and the fourth surface S4 may be an aspheric surface (ASphere).

[0211] FIG. 12 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of the object side surface (third surface S3) and the sensor side surface (fourth surface S4) of the second lens 120 at room temperature (about 22° C.).

[0212] Also, Fig. 13 shows data on lens thickness according to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_2 in Fig. 13 is the central thickness of the second lens 120. That is, D_2 is the thickness (mm) of the second lens 120 at the optical axis OA. Also, D_2_ET in Fig. 13 is the thickness (mm) of the second lens 120 in the optical axis OA direction at the end of the effective area. More specifically, D_2_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (third surface S3) of the second lens 120 and the end of the effective area of ​​the sensor side surface (fourth surface S4) of the second lens 120.

[0213] 9, 12 and 13, the thickness of the second lens 120 in the optical axis OA direction becomes thinner as it extends from the optical axis OA toward the end of the effective diameter of the second lens 120. More specifically, the thickness of the second lens 120 in the optical axis OA direction in the range from the optical axis OA to the end of the effective diameter of the third surface S3 has a maximum value at the optical axis OA and a minimum value at the end of the effective diameter of the third surface S3.

[0214] Therefore, the second lens 120 can prevent the optical characteristics from being changed due to temperature in the low to high temperature range.

[0215] The third lens 130 is made of a plastic material. The third lens 130 has a positive (+) refractive power on the optical axis OA. The fifth surface S5 of the third lens 130 may have a convex shape on the optical axis OA. The sixth surface S6 may have a concave shape on the optical axis OA. The third lens 130 may have a meniscus shape that bulges toward the object side on the optical axis OA. The fifth surface S5 may be an aspheric surface (Asphere), and the sixth surface S6 may be an aspheric surface (ASphere).

[0216] FIG. 14 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of the object side surface (fifth surface S5) and the sensor side surface (sixth surface S6) of the third lens 130 at room temperature (approximately 22° C.).

[0217] Also, Fig. 15 shows data on lens thickness according to the height in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_3 in Fig. 15 is the central thickness of the first lens 110. That is, D_3 is the thickness (mm) of the first lens 110 at the optical axis OA. Also, D_3_ET in Fig. 15 is the thickness (mm) of the third lens 130 in the optical axis OA direction at the end of the effective area. More specifically, D_3_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (fifth surface S5) of the third lens 130 and the end of the effective area of ​​the sensor side surface (sixth surface S6) of the third lens 130.

[0218] 9, 14, and 15, the thickness of the third lens 130 in the optical axis OA direction increases as it extends from the optical axis OA toward the end of the effective diameter of the third lens 130. More specifically, the thickness of the third lens 130 in the optical axis OA direction in the range from the optical axis OA to the end of the effective diameter of the fifth surface S5 has a maximum value at the end of the effective diameter of the fifth surface S5, and a minimum value at the optical axis OA.

[0219] Therefore, the third lens 130 can prevent the optical characteristics from being changed due to temperature in the low to high temperature range.

[0220] The refractive power of the first lens 110 is different from the refractive powers of the second lens 120 and the third lens 130. For example, the refractive power of the first lens 110 may be about 1.2 times or more the refractive powers of the second lens 120 and the third lens 130. In particular, the refractive power of the first lens 110 may be about 1.5 times or more the refractive powers of the second lens 120 and the third lens 130. More particularly, the refractive power of the first lens 110 may be about 1.8 times or more the refractive powers of the second lens 120 and the third lens 130.

[0221] In addition, the refractive power of the second lens 120 is different from the refractive power of the third lens 130. For example, the refractive power of the second lens 120 may be about 10 times or more than the refractive power of the third lens 130. In particular, the refractive power of the second lens 120 may be about 15 times or more than the refractive power of the third lens 130. More particularly, the refractive power of the second lens 120 may be about 20 times or more than the refractive power of the third lens 130.

[0222] In addition, the Abbe number of the first lens 110 may be different from those of the second lens 120 and the third lens 130. For example, the difference between the Abbe number of the first lens 110 and those of the second lens 120 and the third lens 130 may be 10 or less. In more detail, the Abbe number of the first lens 110 may be greater than those of the second lens 120 and the third lens 130 within the above range.

[0223] In the optical system 1000 according to the first embodiment, the aspheric coefficient values ​​of the lens surfaces are as shown in FIG.

[0224] In the optical system 1000 according to the first embodiment, the distance (first distance) between the first lens 110 and the second lens 120 at room temperature (about 22° C.) is as shown in Fig. 17. The distance (second distance) between the second lens 120 and the third lens 130 at room temperature (about 22° C.) is as shown in Fig. 18.

[0225] 17, the first distance decreases from the optical axis OA toward the first point L1, which is the end of the effective diameter of the second surface S2. The first point L1 is an approximation of the effective radius of the second surface S2, which faces the optical axis OA and has a smaller effective diameter. In other words, the first point L1 is an approximation of 1 / 2 the effective diameter of the second surface S2 shown in FIG.

[0226] The first distance has a maximum value at the optical axis OA. The first distance has a minimum value at the first point L1. The maximum value of the first distance may be about 1.1 to about 3 times the minimum value. For example, the maximum value of the first distance may be about 1.2 times the minimum value.

[0227] 18, the second distance increases as it extends to the second point L2, which is the end of the effective diameter of the fourth surface S4 on the optical axis OA. The second point L2 is an approximation of the effective radius of the fourth surface S4, which has a smaller effective diameter. That is, the second point L2 is an approximation of 1 / 2 the effective diameter of the fourth surface S4 shown in FIG.

[0228] The second distance has a maximum value at the second point L2. The second distance has a minimum value at the optical axis OA. The maximum value of the second distance may be about two to four times the minimum value. For example, the maximum value of the second distance may be about 2.6 times the minimum value.

[0229] As a result, the optical system 1000 has improved optical characteristics. In particular, the distance between the first lens 110 and the second lens 120 and the distance between the second lens 120 and the third lens 130 are set at intervals (first interval, second interval) according to positions. Therefore, the optical system 1000 can prevent optical characteristics from changing in a temperature range from low to high. Therefore, the optical system and camera module according to the first embodiment can maintain improved optical characteristics in various temperature ranges.

[0230] Fig. 19 is a graph showing relative illumination for each field of the optical system according to Example 1. Fig. 20 shows data on distortion characteristics of the optical system according to Example 1. Figs. 19 and 20 show data at room temperature (about 22°C).

[0231] 19, the optical system 1000 according to the first embodiment has excellent light amount ratio characteristics in the 0 field region (center region) to 1.0 field region (edge ​​region) of the image sensor 300. For example, the optical system 1000 may have a peripheral light amount ratio of about 70% or more. In more detail, when the light amount ratio of the 0 field region is 100%, the optical system 1000 may have a light amount ratio of about 80% or more in the 0.5 field region and a light amount ratio of about 70% or more in the 1.0 field region.

[0232] 20, the optical system 1000 according to the first embodiment may have a barrel distortion shape in which the edge portion of the image is distorted outward, and may have a distortion of about 1.1179% and a TV-distortion of about -0.7453%.

[0233] 21 to 29 are graphs showing the diffraction MTF characteristics and the degree of aberration of the optical system 1000 according to temperature.

[0234] Figures 21 and 22 are graphs showing the diffraction MTF characteristics of the optical system 1000 at low temperature (-40°C). Figures 24 and 25 are graphs showing the diffraction MTF characteristics of the optical system 1000 at room temperature (22°C). Figures 27 and 28 are graphs showing the diffraction MTF characteristics of the optical system 1000 at high temperature (90°C).

[0235] 23, 26 and 29 are graphs showing the degree of aberration of the optical system 1000 at low temperature (-40°C), room temperature (22°C) and high temperature (90°C). That is, FIG. 23, 26 and 29 are graphs showing the measurement of the spherical aberration, astigmatic field curves and distortion from left to right. In FIG. 23, 26 and 29, the X-axis represents the focal length (mm) or the degree of distortion (%). Also, the Y-axis represents the height of the image. Also, the graphs showing the spherical aberration are for light of wavelength bands of about 920 nm, about 940 nm and about 960 nm. Also, the graphs showing the astigmatism and distortion are for light of wavelength band 940 nm.

[0236] It can be interpreted that the closer each curve is to the Y-axis in the aberration degree of Fig. 23, Fig. 26, and Fig. 29, the better the aberration correction function. With reference to Fig. 23, Fig. 26, and Fig. 29, the measurement values ​​in most areas of the optical system 1000 according to the first example are adjacent to the Y-axis.

[0237] 21 to 29, the optical system 1000 according to the first embodiment has small changes in MTF and aberration characteristics even when the temperature changes in the range from low temperature (-40°C) to high temperature (90°C). More specifically, the MTF characteristics at low temperature (-40°C) and high temperature (90°C) are less than 10% of those at room temperature (22°C).

[0238] That is, the optical system 1000 according to the first embodiment can maintain excellent optical characteristics in various temperature ranges. More specifically, the first lens 110 has a different material from the second lens 120 and the third lens 130. For example, the first lens 110 includes a glass material. Also, the second lens 120 and the third lens 130 include a plastic material. Thus, as the temperature increases, the refractive index of the first lens 110 increases. Also, the refractive index of the second lens 120 and the third lens 130 decreases.

[0239] The lenses 110, 120, and 130 according to the first embodiment have a set refractive index, shape, and thickness. Therefore, the change in focal length caused by the change in refractive index due to temperature change can be mutually compensated for. Therefore, the optical system 1000 can prevent the optical characteristics from changing in the temperature range from low temperature (-40°C) to high temperature (90°C). In addition, the improved optical characteristics can be maintained.

[0240] The optical system 1000 according to the second embodiment will be described in detail with reference to FIGS.

[0241] 30, the optical system 1000 according to the second embodiment includes a first lens 110, a second lens 120, a third lens 130, and an image sensor 300, which are sequentially arranged from the object side to the sensor side. The lenses 110, 120, and 130 are sequentially arranged along an optical axis OA of the optical system 1000.

[0242] In the optical system 1000 according to the second embodiment, a diaphragm 600 is disposed between the sensor side surface (second surface S2) of the first lens 110 and the object side surface (third surface S3) of the second lens 120.

[0243] In detail, the aperture 600 is between the sensor side (second surface S2) of the first lens 110 and the object side (third surface S3) of the second lens 120 and is spaced apart from the sensor side (second surface S2) of the first lens 110.

[0244] For example, the aperture 600 may be spaced apart from the sensor side (second surface S2) of the first lens 110 as shown in Equations 50 and 51.

[0245] In addition, a filter 500 is disposed between the lenses 100 and the image sensor 300. A cover glass 400 is disposed between the filter 500 and the image sensor 300.

[0246] Fig. 31 shows data on the radius of curvature of the lenses 110, 120, 130 according to the second embodiment, the thickness of each lens on the optical axis OA, the distance between each lens on the optical axis OA, the refractive index for light in the t-line (1013.98 nm) wavelength band, the Abbe's number, the clear aperture (CA), and the focal length. In more detail, Fig. 31 shows data at room temperature (approximately 22°C).

[0247] 30 and 31, the first lens 110 is made of a glass material. The first lens 110 has a positive (+) refractive power on the optical axis OA. The first surface S1 of the first lens 110 may have a convex shape on the optical axis OA. The second surface S2 may have a concave shape on the optical axis OA. The first lens 110 may have a meniscus shape that bulges toward the object side on the optical axis OA. The first surface S1 may be a spherical surface, and the second surface S2 may be a spherical surface.

[0248] FIG. 32 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of the object side surface (first surface S1) and the sensor side surface (second surface S2) of the first lens 110 at room temperature (approximately 22° C.).

[0249] Also, Fig. 33 shows data on lens thickness according to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_1 in Fig. 33 is the central thickness of the first lens 110. That is, D_1 is the thickness (mm) of the first lens 110 at the optical axis OA. Also, D_1_ET in Fig. 33 is the thickness (mm) of the first lens 110 in the optical axis OA direction at the end of the effective area. More specifically, D_1_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (first surface S1) of the first lens 110 and the end of the effective area of ​​the sensor side surface (second surface S2) of the first lens 110.

[0250] 31 to 33, the thickness of the first lens 110 in the optical axis OA direction increases as the first lens 110 extends from the optical axis OA toward the end of the effective diameter of the first lens 110.

[0251] Therefore, the first lens 110 can have improved aberration control characteristics by controlling incident light.

[0252] The second lens 120 is made of a plastic material. The second lens 120 has a positive (+) refractive power on the optical axis OA. The third surface S3 of the second lens 120 may have a concave shape on the optical axis OA. The fourth surface S4 may have a convex shape on the optical axis OA. The second lens 120 may have a meniscus shape that bulges toward the sensor side on the optical axis OA. The third surface S3 may be an aspheric surface (Asphere), and the fourth surface S4 may be an aspheric surface (ASphere).

[0253] FIG. 34 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of the object side surface (third surface S3) and the sensor side surface (fourth surface S4) of the second lens 120 at room temperature (approximately 22° C.).

[0254] Also, Fig. 35 shows data on lens thickness according to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_1 in Fig. 35 is the central thickness of the first lens 110. That is, D_1 is the thickness (mm) of the first lens 110 at the optical axis OA. Also, D_1_ET in Fig. 35 is the thickness (mm) of the first lens 110 in the optical axis OA direction at the end of the effective area. More specifically, D_1_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (first surface S1) of the first lens 110 and the end of the effective area of ​​the sensor side surface (second surface S2) of the first lens 110.

[0255] 31, 35, and 36, the thickness of the second lens 120 in the optical axis OA direction becomes thinner as it extends from the optical axis OA toward the end of the effective diameter of the second lens 120. More specifically, the thickness of the second lens 120 in the optical axis OA direction in the range from the optical axis OA to the end of the effective diameter of the third surface S3 has a maximum value at the optical axis OA.

[0256] Therefore, the second lens 120 can prevent the optical characteristics from being changed due to temperature in the low to high temperature range.

[0257] The third lens 130 is made of a plastic material. The third lens 130 has a positive (+) refractive power on the optical axis OA. The fifth surface S5 of the third lens 130 may have a convex shape on the optical axis OA. The sixth surface S6 may have a concave shape on the optical axis OA. The third lens 130 may have a meniscus shape that bulges toward the object side on the optical axis OA. The fifth surface S5 may be an aspheric surface (Asphere), and the sixth surface S6 may be an aspheric surface (ASphere).

[0258] FIG. 36 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of each of the object side surface (fifth surface S5) and the sensor side surface (sixth surface S6) of the third lens 130 at room temperature (approximately 22° C.).

[0259] Also, Fig. 37 shows data on lens thickness according to the height in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_3 in Fig. 37 is the central thickness of the first lens 110. That is, D_3 is the thickness (mm) of the first lens 110 at the optical axis OA. Also, D_3_ET in Fig. 37 is the thickness (mm) of the third lens 130 in the optical axis OA direction at the end of the effective area. More specifically, D_3_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (fifth surface S5) of the third lens 130 and the end of the effective area of ​​the sensor side surface (sixth surface S6) of the third lens 130.

[0260] 31, 36 and 37, the thickness of the third lens 130 in the direction of the optical axis OA increases as the third lens 130 extends from the optical axis OA toward the end of the effective diameter of the third lens 130.

[0261] Therefore, the third lens 130 can prevent the optical characteristics from being changed due to temperature in the low to high temperature range.

[0262] The refractive power of the first lens 110 is different from the refractive powers of the second lens 120 and the third lens 130. For example, the refractive power of the first lens 110 may be about twice or more the refractive powers of the second lens 120 and the third lens 130. In particular, the refractive power of the first lens 110 may be about 2.5 times or more the refractive powers of the second lens 120 and the third lens 130. More particularly, the refractive power of the first lens 110 may be about three times or more the refractive powers of the second lens 120 and the third lens 130.

[0263] In addition, the refractive power of the second lens 120 is different from the refractive power of the third lens 130. For example, the refractive power of the second lens 120 may be about 1.2 times or more the refractive power of the third lens 130. In particular, the refractive power of the second lens 120 may be about 1.5 times or more the refractive power of the third lens 130. More particularly, the refractive power of the second lens 120 may be about 1.7 times or more the refractive power of the third lens 130.

[0264] In addition, the Abbe number of the first lens 110 may be different from those of the second lens 120 and the third lens 130. For example, the difference between the Abbe number of the first lens 110 and those of the second lens 120 and the third lens 130 may be 10 or less. In more detail, the Abbe number of the first lens 110 may be greater than those of the second lens 120 and the third lens 130 within the above range.

[0265] In the optical system 1000 according to the second embodiment, the aspheric coefficient values ​​of the lens surfaces are as shown in FIG.

[0266] In the optical system 1000 according to the second embodiment, the distance (first distance) between the first lens 110 and the second lens 120 at room temperature (about 22° C.) is as shown in Fig. 39. The distance (second distance) between the second lens 120 and the third lens 130 at room temperature (about 22° C.) is as shown in Fig. 40.

[0267] 39, the first distance decreases from the optical axis OA toward the first point L1, which is the end of the effective diameter of the second surface S2. The first point L1 is an approximation of the effective radius of the second surface S2, which faces the optical axis OA and has a smaller effective diameter. In other words, the first point L1 is an approximation of 1 / 2 the effective diameter of the second surface S2 shown in FIG.

[0268] The first distance has a maximum value at the optical axis OA. The first distance has a minimum value at the first point L1. The maximum value of the first distance may be about 1.1 to about 3 times the minimum value. For example, the maximum value of the first distance may be about 1.2 times the minimum value.

[0269] 40, the second distance increases from the optical axis OA toward the second point L2, which is the end of the effective diameter of the fourth surface S4. The second point L2 is an approximation of the effective radius of the fourth surface S4, which has a small effective diameter. In other words, the second point L2 is an approximation of 1 / 2 the effective diameter of the fourth surface S4 shown in FIG.

[0270] The second distance has a maximum value at the second point L2. The second distance has a minimum value at the optical axis OA. The maximum value of the second distance may be about two to four times the minimum value. For example, the maximum value of the second distance may be about 2.6 times the minimum value.

[0271] As a result, the optical system 1000 has improved optical characteristics. In particular, the distance between the first lens 110 and the second lens 120 and the distance between the second lens 120 and the third lens 130 are set at intervals (first interval, second interval) according to positions. Therefore, the optical system 1000 can prevent optical characteristics from changing in a temperature range from low to high. Therefore, the optical system and camera module according to the second embodiment can maintain improved optical characteristics in various temperature ranges.

[0272] Fig. 41 is a graph showing relative illumination for each field of the optical system according to Example 2. Fig. 42 shows data on distortion characteristics of the optical system according to Example 2. Figs. 41 and 42 show data at room temperature (about 22°C).

[0273] 41, the optical system 1000 according to the second embodiment has excellent light amount ratio characteristics in the 0 field region (center region) to 1.0 field region (edge ​​region) of the image sensor 300. For example, the optical system 1000 may have a peripheral light amount ratio of about 70% or more. In more detail, when the light amount ratio of the 0 field region is 100%, the optical system 1000 may have a light amount ratio of about 80% or more in the 0.5 field region and a light amount ratio of about 70% or more in the 1.0 field region.

[0274] 42, the optical system 1000 according to the second embodiment may have a barrel distortion shape in which the edge portion of the image is distorted outward, and may have a distortion of about 0.9824% and a TV-distortion of about -0.7338%.

[0275] 43 to 51 are graphs showing the diffraction MTF characteristics and the degree of aberration of the optical system 1000 according to temperature.

[0276] In detail, Fig. 43 and Fig. 44 are graphs showing the diffraction MTF characteristics of the optical system 1000 at low temperature (-40°C), Fig. 46 and Fig. 47 are graphs showing the diffraction MTF characteristics of the optical system 1000 at room temperature (22°C), Fig. 49 and Fig. 50 are graphs showing the diffraction MTF characteristics of the optical system 1000 at high temperature (90°C).

[0277] 45, 48 and 51 are graphs showing the degree of aberration of the optical system 1000 at low temperature (-40°C), room temperature (22°C) and high temperature (90°C). That is, FIG. 45, 48 and 51 are graphs showing the measurement of the spherical aberration, astigmatic field curves and distortion from left to right. In FIG. 45, 48 and 51, the X-axis represents the focal length (mm) or the degree of distortion (%). Also, the Y-axis represents the height of the image. Also, the graphs showing the spherical aberration are for light of wavelength bands of about 920 nm, about 940 nm and about 960 nm. Also, the graphs showing the astigmatism and distortion are for light of wavelength band 940 nm.

[0278] It can be interpreted that the closer each curve is to the Y-axis in the aberration degree of Figures 45, 48, and 51, the better the aberration correction function. With reference to Figures 45, 48, and 51, the measurement values ​​of the optical system 1000 according to the second example are adjacent to the Y-axis in most areas.

[0279] 43 to 51, the optical system 1000 according to the second embodiment has small changes in MTF and aberration characteristics even when the temperature changes from low temperature (-40°C) to high temperature (90°C). More specifically, the MTF characteristics at low temperature (-40°C) and high temperature (90°C) are less than 10% of those at room temperature (22°C).

[0280] The optical system 1000 according to the second embodiment can maintain excellent optical characteristics in various temperature ranges. More specifically, the first lens 110 has a different material from the second lens 120 and the third lens 130. For example, the first lens 110 includes a glass material. Also, the second lens 120 and the third lens 130 include a plastic material. Thus, when the temperature increases, the refractive index of the first lens 110 increases. Also, the refractive index of the second lens 120 and the third lens 130 decreases.

[0281] In this case, the lenses 110, 120, and 130 according to the second embodiment have a set refractive index, shape, and thickness. Therefore, the change in focal length caused by the change in refractive index that changes according to temperature can be mutually compensated for. Therefore, the optical system 1000 can prevent the optical characteristics from changing in a temperature range from low temperature (-40°C) to high temperature (90°C). In addition, the improved optical characteristics can be maintained.

[0282] The optical system 1000 according to the third embodiment will be described in detail with reference to FIGS.

[0283] 52, the optical system 1000 according to the third embodiment includes a first lens 110, a second lens 120, a third lens 130, and an image sensor 300, which are sequentially arranged from the object side to the sensor side. The lenses 110, 120, and 130 are sequentially arranged along the optical axis OA of the optical system 1000.

[0284] In addition, between the sensor side surface (second surface S2) of the first lens 110 and the object side surface (third surface S3) of the second lens 120, a diaphragm 600 is disposed.

[0285] In detail, the aperture 600 is between the sensor side (second surface S2) of the first lens 110 and the object side (third surface S3) of the second lens 120 and is spaced apart from the sensor side (second surface S2) of the first lens 110.

[0286] For example, the aperture 600 is spaced apart from the sensor side (second surface S2) of the first lens 110 as shown in Equations 50 and 51.

[0287] In addition, a filter 500 is disposed between the plurality of lenses 100 and the image sensor 300. In addition, a cover glass 400 is disposed between the filter 500 and the image sensor 300.

[0288] Fig. 53 shows data on the radius of curvature of the lenses 110, 120, 130 according to the third embodiment, the thickness of each lens on the optical axis OA, the distance between each lens on the optical axis OA, the refractive index for light in the t-line (1013.98 nm) wavelength band, the Abbe's number, the clear aperture (CA), and the focal length. Here, Fig. 53 shows data at room temperature (about 22°C).

[0289] 52 and 53, the first lens 110 is made of a glass material. The first lens 110 has a positive (+) refractive power on the optical axis OA. The first surface S1 of the first lens 110 may have a convex shape on the optical axis OA. The second surface S2 may have a concave shape on the optical axis OA. The first lens 110 may have a meniscus shape that bulges toward the object side on the optical axis OA. The first surface S1 may be a spherical surface, and the second surface S2 may be a spherical surface.

[0290] FIG. 54 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of each of the object side surface (first surface S1) and the sensor side surface (second surface S2) of the first lens 110 at room temperature (approximately 22° C.).

[0291] Also, FIG. 55 shows data on lens thickness according to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_1 in FIG. 55 is the central thickness of the first lens 110. That is, D_1 is the thickness (mm) of the first lens 110 at the optical axis OA. Also, D_1_ET in FIG. 55 is the thickness (mm) of the first lens 110 in the optical axis OA direction at the end of the effective area. More specifically, D_1_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (first surface S1) of the first lens 110 and the end of the effective area of ​​the sensor side surface (second surface S2) of the first lens 110.

[0292] 53 to 55, the thickness of the first lens 110 in the optical axis OA direction increases as the first lens 110 extends from the optical axis OA toward the end of the effective diameter of the first lens 110.

[0293] Therefore, the first lens 110 can have improved aberration control characteristics by controlling incident light.

[0294] The second lens 120 is made of a plastic material. The second lens 120 has a positive (+) refractive power on the optical axis OA. The third surface S3 of the second lens 120 has a concave shape on the optical axis OA. The fourth surface S4 may have a convex shape on the optical axis OA. The second lens 120 may have a meniscus shape that bulges toward the sensor on the optical axis OA. The third surface S3 may be an aspheric surface (Asphere), and the fourth surface S4 may be an aspheric surface (ASphere).

[0295] FIG. 56 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of each of the object side surface (third surface S3) and the sensor side surface (fourth surface S4) of the second lens 120 at room temperature (approximately 22° C.).

[0296] Also, FIG. 57 shows data on lens thickness according to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_1 in FIG. 57 is the central thickness of the first lens 110. That is, D_1 is the thickness (mm) of the first lens 110 at the optical axis OA. Also, D_1_ET in FIG. 57 is the thickness (mm) of the first lens 110 in the optical axis OA direction at the end of the effective area. More specifically, D_1_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (first surface S1) of the first lens 110 and the end of the effective area of ​​the sensor side surface (second surface S2) of the first lens 110.

[0297] 52, 56, and 57, the thickness of the second lens 120 in the optical axis OA direction becomes thinner as it goes from the optical axis OA toward the end of the effective diameter of the second lens 120. More specifically, the thickness of the second lens 120 in the optical axis OA direction in the range from the optical axis OA to the end of the effective diameter of the third surface S3 has a maximum value at the optical axis OA.

[0298] Therefore, the second lens 120 can prevent the optical characteristics from being changed due to temperature in the low to high temperature range.

[0299] The third lens 130 is made of a plastic material. The third lens 130 has a positive (+) refractive power on the optical axis OA. The fifth surface S5 of the third lens 130 may have a convex shape on the optical axis OA. The sixth surface S6 may have a concave shape on the optical axis OA. The third lens 130 may have a meniscus shape that bulges toward the object side on the optical axis OA. The fifth surface S5 may be an aspheric surface (Asphere), and the sixth surface S6 may be an aspheric surface (ASphere).

[0300] FIG. 58 shows Sag data corresponding to the height (at 0.2 mm intervals) in the vertical direction of the optical axis OA of each of the object side surface (fifth surface S5) and the sensor side surface (sixth surface S6) of the third lens 130 at room temperature (approximately 22° C.).

[0301] Also, Fig. 59 shows data on lens thickness according to the height in the vertical direction of the optical axis OA at room temperature (approximately 22°C). More specifically, D_3 in Fig. 59 is the central thickness of the first lens 110. That is, D_3 is the thickness (mm) of the first lens 110 at the optical axis OA. Also, D_3_ET in Fig. 59 is the thickness (mm) of the third lens 130 in the optical axis OA direction at the end of the effective area. More specifically, D_3_ET is the distance (mm) in the optical axis OA direction between the end of the effective area of ​​the object side surface (fifth surface S5) of the third lens 130 and the end of the effective area of ​​the sensor side surface (sixth surface S6) of the third lens 130.

[0302] 52, 58 and 59, the thickness of the third lens 130 in the optical axis OA direction becomes thicker from the optical axis OA toward the end of the effective diameter of the third lens 130. In particular, the thickness of the third lens 130 in the optical axis OA direction has a minimum value at the optical axis OA.

[0303] Therefore, the third lens 130 can prevent the optical characteristics from being changed due to temperature in the low to high temperature range.

[0304] The refractive power of the first lens 110 is different from the refractive powers of the second lens 120 and the third lens 130. For example, the refractive power of the first lens 110 may be about 1.3 times or more the refractive powers of the second lens 120 and the third lens 130. In particular, the refractive power of the first lens 110 may be about 1.6 times or more the refractive powers of the second lens 120 and the third lens 130. More particularly, the refractive power of the first lens 110 may be about 1.9 times or more the refractive powers of the second lens 120 and the third lens 130.

[0305] In addition, the refractive power of the second lens 120 is different from the refractive power of the third lens 130. For example, the refractive power of the second lens 120 may be about 1.5 times or more the refractive power of the third lens 130. In particular, the refractive power of the second lens 120 may be about 2.5 times or more the refractive power of the third lens 130. More particularly, the refractive power of the second lens 120 may be about 3.5 times or more the refractive power of the third lens 130.

[0306] In addition, the Abbe number of the first lens 110 may be different from those of the second lens 120 and the third lens 130. For example, the difference between the Abbe number of the first lens 110 and those of the second lens 120 and the third lens 130 may be 10 or less. In more detail, the Abbe number of the first lens 110 may be greater than those of the second lens 120 and the third lens 130 within the above range.

[0307] In the optical system 1000 according to the third embodiment, the aspheric coefficient values ​​of the lens surfaces are as shown in FIG.

[0308] In the optical system 1000 according to the third embodiment, the distance (first distance) between the first lens 110 and the second lens 120 at room temperature (about 22° C.) is as shown in Fig. 61. The distance (second distance) between the second lens 120 and the third lens 130 at room temperature (about 22° C.) is as shown in Fig. 62.

[0309] 61, the first distance decreases from the optical axis OA toward the first point L1, which is the end of the effective diameter of the second surface S2. The first point L1 is an approximation of the effective radius of the second surface S2, which faces the optical axis OA and has a smaller effective diameter. In other words, the first point L1 is an approximation of 1 / 2 the effective diameter of the second surface S2 shown in FIG.

[0310] The first distance has a maximum value at the optical axis OA. The first distance has a minimum value at the first point L1. The maximum value of the first distance may be about 1.1 to about 3 times the minimum value. For example, the maximum value of the first distance may be about 1.2 times the minimum value.

[0311] 62, the second distance increases from the optical axis OA toward the second point L2, which is the end of the effective diameter of the fourth surface S4. The second point L2 is an approximation of the effective radius of the fourth surface S4, which has a small effective diameter. In other words, the second point L2 is an approximation of 1 / 2 the effective diameter of the fourth surface S4 shown in FIG.

[0312] The second distance has a maximum value at the second point L2. The second distance has a minimum value at the optical axis OA. The maximum value of the second distance may be about two to four times the minimum value. For example, the maximum value of the second distance may be about 2.6 times the minimum value.

[0313] As a result, the optical system 1000 has improved optical characteristics. In particular, the distance between the first lens 110 and the second lens 120 and the distance between the second lens 120 and the third lens 130 are set at intervals (first interval, second interval) according to positions. Therefore, the optical system 1000 can prevent optical characteristics from changing in a temperature range from low to high. Therefore, the optical system and camera module according to the third embodiment can maintain improved optical characteristics in various temperature ranges.

[0314] Fig. 63 is a graph showing relative illumination for each field of the optical system according to Example 3. Fig. 64 shows data on distortion characteristics of the optical system according to Example 3. Figs. 63 and 64 show data at room temperature (about 22°C).

[0315] 63, the optical system 1000 according to the third embodiment has excellent light amount ratio characteristics in the 0 field region (center region) to 1.0 field region (edge ​​region) of the image sensor 300. For example, the optical system 1000 may have a peripheral light amount ratio of about 70% or more. In more detail, when the light amount ratio of the 0 field region is 100%, the optical system 1000 may have a light amount ratio of about 80% or more in the 0.5 field region and a light amount ratio of about 70% or more in the 1.0 field region.

[0316] 64, the optical system 1000 according to the third embodiment may have a barrel distortion shape in which the edge portion of the image is distorted outward, and may have a distortion of about 0.9686% and a TV-distortion of about -0.7486%.

[0317] 65 to 73 are graphs showing the diffraction MTF characteristics and the degree of aberration of the optical system 1000 according to temperature.

[0318] In detail, Fig. 65 and Fig. 66 are graphs showing the diffraction MTF characteristics of the optical system 1000 at low temperature (-40°C), Fig. 68 and Fig. 69 are graphs showing the diffraction MTF characteristics of the optical system 1000 at room temperature (22°C), Fig. 71 and Fig. 72 are graphs showing the diffraction MTF characteristics of the optical system 1000 at high temperature (90°C).

[0319] 67, 70 and 73 are graphs showing the degree of aberration of the optical system 1000 at low temperature (-40°C), room temperature (22°C) and high temperature (90°C). That is, FIG. 67, 70 and 73 are graphs showing the measurement of the spherical aberration, astigmatic field curves and distortion from left to right. In FIG. 67, 70 and 73, the X-axis represents the focal length (mm) or the degree of distortion (%). Also, the Y-axis represents the height of the image. Also, the graphs showing the spherical aberration are for light of wavelength bands of about 920 nm, about 940 nm and about 960 nm. Also, the graphs showing the astigmatism and distortion are for light of wavelength band 940 nm.

[0320] It can be interpreted that the closer each curve is to the Y-axis in the aberration degree of Figures 67, 70, and 73, the better the aberration correction function. With reference to Figures 67, 70, and 73, the measurement values ​​of the optical system 1000 according to the third example are adjacent to the Y-axis in most areas.

[0321] 65 to 73, the optical system 1000 according to the third embodiment has small changes in MTF and aberration characteristics even when the temperature changes in the range from low temperature (-40°C) to high temperature (90°C). More specifically, the MTF characteristics at low temperature (-40°C) and high temperature (90°C) are less than 10% of those at room temperature (22°C).

[0322] The optical system 1000 according to the third embodiment can maintain excellent optical characteristics in various temperature ranges. More specifically, the first lens 110 has a different material from the second lens 120 and the third lens 130. For example, the first lens 110 includes a glass material. Also, the second lens 120 and the third lens 130 include a plastic material. Thus, as the temperature increases, the refractive index of the first lens 110 increases. Also, the refractive index of the second lens 120 and the third lens 130 decreases.

[0323] The lenses 110, 120, and 130 according to the third embodiment have a set refractive index, shape, and thickness. Therefore, the change in focal length caused by the change in refractive index due to temperature change can be mutually compensated for. Therefore, the optical system 1000 can prevent the optical characteristics from changing in the temperature range from low temperature (-40°C) to high temperature (90°C). In addition, the optical characteristics can be improved.

[0324] The optical system 1000 according to the fourth embodiment will be described in detail with reference to FIGS.

[0325] The fourth embodiment is the same as the first embodiment described above, except for the first and second intervals. Therefore, the first and second intervals will be mainly described. The rest of the description is omitted because it is the same as the first embodiment.

[0326] 74, the first and second intervals of the fourth embodiment are different from the first and second intervals of the first embodiment. More specifically, the first interval of the fourth embodiment is 0.008 mm smaller than the first interval of the first embodiment. Also, the second interval of the fourth embodiment is 0.008 mm larger than the second interval of the first embodiment.

[0327] This improves the reliability of the optical system 1000.

[0328] Fig. 75 is an MTF performance graph (room temperature) of the optical system according to Example 4. Fig. 76 is an MTF performance graph (high temperature) of the optical system according to Example 4. Fig. 77 is an MTF performance graph (room temperature) of the optical system according to Example 1. Fig. 78 is an MTF performance graph (high temperature) of the optical system according to Example 1.

[0329] The Peripheral best displayed in Figures 75 to 78 is an indication of peripheral MTF performance. Also, the Center best is an indication of MTF performance with respect to the optical axis. The closer the Peripheral best and Center best indices are, the better the MTF performance is. With reference to Figures 75 to 78, the optical system of the fourth embodiment has better MTF performance at room temperature and high temperature than the optical system of the first embodiment.

[0330] 75 and 76, the optical system 1000 according to the fourth embodiment can minimize the reduction in resolution at the periphery after a reliability test. That is, the size of the first interval and the second interval is changed in the optical system 1000 according to the fourth embodiment. As a result, when the position of the lens is changed due to a change in temperature, the position of the periphery of each lens can be optimized. The periphery refers to the area adjacent to the end of the effective diameter from the optical axis. As a result, the optical system 1000 according to the fourth embodiment can prevent the reduction in resolution at the periphery. Also, the curvature of the upper surface can be minimized.

[0331] The features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to one embodiment. In addition, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by a person having ordinary skill in the art to which the embodiment belongs. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

[0332] In addition, the above description has been centered on the embodiments, but these are merely examples and do not limit the present invention. A person having ordinary skill in the art to which the present invention pertains may make various modifications and applications not exemplified above within the scope of the essential characteristics of the present embodiments. For example, each component specifically presented in the embodiments may be modified and implemented. The differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. It consists of a first lens, a second lens, and a third lens arranged along the optical axis from the object side to the image side, Including an aperture positioned between the first lens and the second lens, The refractive power of the first lens is positive, The refractive power of the second lens is positive. The second lens and the third lens are made of the same material. The first lens and the second lens are made of different materials. Of the object sides or image sides of the first to third lenses, the surface with the largest absolute value of the radius of curvature along the optical axis is the object side of the second lens. The effective diameter of the object side of the first lens is shorter than the effective diameter of the image side of the third lens. An optical system in which, among the object side surfaces or image side surfaces of the first to third lenses, the surface with the smallest absolute value of the radius of curvature along the optical axis is the image side surface of the third lens.

2. The optical system according to claim 1, wherein the refractive index of the first lens is the largest among the refractive indices of the first to third lenses.

3. The optical system according to claim 1 or 2, wherein among the object side surface and the image side surface of the first lens, the object side surface and the image side surface of the second lens, and the object side surface of the third lens, the surface with the smallest absolute value of the radius of curvature in the optical axis is the object side surface of the third lens.

4. In the optical axis, the thickness of the first lens is greater than the thickness of the second lens in the optical axis. The optical system according to claim 3, wherein the thickness of the second lens in the optical axis is greater than the thickness of the third lens in the optical axis.

5. The optical system according to claim 4, wherein the surface with the largest absolute value of radius of curvature in the optical axis among the object side surface and the image side surface of the first lens, the image side surface of the second lens, and the object side surface and the image side surface of the third lens is the image side surface of the first lens.

6. The absolute value of the radius of curvature of the object side surface of the first lens and the absolute value of the radius of curvature of the image side surface of the second lens are the same. The absolute value of the radius of curvature of the image side surface of the first lens and the absolute value of the radius of curvature of the object side surface of the second lens are the same. The optical system according to claim 5, wherein the absolute value of the radius of curvature is a natural number excluding the decimal part.

7. The optical system according to claim 4, wherein the refractive power of the third lens is positive.

8. The optical system according to claim 7, wherein the focal length of the third lens is the longest of the focal lengths of the first to third lenses.

9. The optical system according to claim 8, wherein the focal length of the first lens is the shortest of the focal lengths of the first to third lenses.

10. The optical system according to claim 1 or 2, wherein the refractive index of the first lens is 1.7 or greater.

Images