CN112505887A

CN112505887A - Optical system, camera module and terminal equipment

Info

Publication number: CN112505887A
Application number: CN202011449516.6A
Authority: CN
Inventors: 杨健; 李明
Original assignee: Jiangxi Jingchao Optical Co Ltd
Current assignee: Jiangxi Jingchao Optical Co Ltd
Priority date: 2020-12-11
Filing date: 2020-12-11
Publication date: 2021-03-16

Abstract

The embodiment of the application discloses an optical system, a camera module and terminal equipment. The optical system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens element and the fourth lens element have refractive power; the second lens element and the fifth lens element have positive refractive power, and the third lens element and the sixth lens element have negative refractive power. The second lens element has a convex object-side surface and a convex image-side surface at a paraxial region, the third lens element has a concave image-side surface at a paraxial region, the fifth lens element has a convex image-side surface at a paraxial region, and the sixth lens element has a concave image-side surface at a paraxial region. The optical system satisfies: 0.1< cts/sds < 2. By reasonably configuring the refractive power and the surface shape of the first lens element to the sixth lens element in the optical system and limiting cts/sds, the system realizes miniaturization, large field angle and high pixel imaging quality, and reduces the size of the opening of the terminal device.

Description

Optical system, camera module and terminal equipment

Technical Field

The application belongs to the technical field of optical imaging, and particularly relates to an optical system, a camera module and terminal equipment.

Background

In recent years, a full-screen mobile phone is popular in the market, and the high screen ratio is a development trend. In this trend, the size of the optical system for photography is required to be reduced, and high image quality is also ensured, so that the specification of the optical system is required to be higher and higher.

Although the existing optical system can meet the requirement of miniaturization, the optical system has a large head, is not beneficial to under-screen packaging of the optical system, has a large screen opening, cannot achieve the visual effect of a full screen, and has a small field angle, so that the shooting requirement of a user cannot be met.

Therefore, how to simultaneously achieve the miniaturization, large field angle and high pixel imaging quality of the optical system, and reduce the size of the opening of the terminal equipment should be the research and development direction in the industry.

Disclosure of Invention

The embodiment of the application provides an optical system, a camera module and a terminal device, wherein the optical system can realize miniaturization, a large field angle and high-pixel imaging quality, and reduce the size of an opening hole of the terminal device.

In a first aspect, an optical system includes a plurality of lenses, each of the plurality of lenses includes a first lens having refractive power and arranged in order from an object side (where an object side is a side on which light is incident) to an image side (where an image side is a side on which light is emitted); the second lens element with positive refractive power has a convex object-side surface and a convex image-side surface at a paraxial region; a third lens element with negative refractive power having a concave image-side surface at paraxial region; a fourth lens element with refractive power; a fifth lens element with positive refractive power having a convex image-side surface at paraxial region; a sixth lens element with negative refractive power having a concave image-side surface at a paraxial region; the optical system further comprises a diaphragm, and the optical system satisfies the following conditional expression: 0.1< cts/sds <2, cts is the distance between the intersection point of the diaphragm and the optical axis to the intersection point of the object side surface of the first lens and the optical axis, and sds is half of the aperture of the diaphragm.

The refractive power is the focal power, and represents the ability of the optical system to deflect light, positive refractive power represents the converging effect of the lens on the light beam, and negative refractive power represents the diverging effect of the lens on the light beam. When the lens has no refractive power, that is, when the focal power is zero, the lens is plane refraction, and at this time, the axially parallel light beams are still axially parallel light beams after being refracted, and the refraction phenomenon does not occur. The first lens element and the fourth lens element with refractive power herein can have positive refractive power, and the first lens element and the fourth lens element can also have negative refractive power.

By reasonably configuring the refractive power of the first lens element to the sixth lens element, the surface shapes of the second lens element, the third lens element, the fifth lens element and the sixth lens element in the optical system and limiting cts/sds, the optical system can realize miniaturization, large field angle and high pixel imaging quality, and reduce the size of the opening of the terminal device. The optical system of this application can reduce terminal equipment screen trompil size under the prerequisite of guaranteeing high imaging quality, is favorable to optical system's screen under the encapsulation, reaches the visual effect of full face screen, in addition, because of having great angle of vision, can obtain wider field of vision, outstanding prospect object satisfies user's the experience of shooing.

Specifically, the diaphragm of this application is located the thing side of first lens and is kept away from first lens setting (diaphragm antedisplacement), and the diaphragm aperture is little, places preceding the diaphragm of small bore and can make the screen trompil littleer also can satisfy into light. By defining cts/sds such that the diaphragm disposed in front is distant from the first lens, the diaphragm is disposed on the cover glass for reducing the screen opening size of the terminal device. The protective glass keeps a certain distance from the lens, the farther the distance is, the larger the light flux is, the lower the MTF performance is, therefore, the farther the distance is, the smaller the aperture of the diaphragm needs to be to balance aberration, therefore cts/sds is more than 0.1, otherwise, the imaging quality of the optical system is influenced; however, the aperture of the diaphragm cannot be too small, otherwise, the f-number of the optical system is increased, the diffraction limit is reduced, and the imaging quality of the optical system is also affected, so cts/sds is less than 2.

In one embodiment, the object-side surface and the image-side surface of each of the first lens element to the sixth lens element are aspheric, which is beneficial to correcting aberration of the optical system and improving imaging quality of the optical system.

In one embodiment, the optical system satisfies the conditional expression: -20 ° < slope 1S1< -0.5 °, slope 1S1 being the angle of inclination at the maximum effective aperture of the object-side face of the first lens. By defining slope 1S1 as a negative number, the included angle between the incident ray and the object side of the first lens is reduced, the aberration is balanced, and if the included angle is too large, the aberration is increased, the relative brightness is reduced, and the imaging quality is affected.

In one embodiment, the optical system satisfies the conditional expression: -1< f12/f36< -0.3, f12 being the combined focal length of the first and second lenses, f36 being the combined focal length of the third to sixth lenses. The range of f12/f36 is reasonably limited, which is beneficial to reducing the influence of chromatic aberration on the performance of the optical system, if f12/f36< -1, the refractive power is distributed to the third lens element to the sixth lens element, the sensitivity is increased, and the assembly mass production is not facilitated; if f12/f36 > -0.3, the MTF performance of the optical system is affected.

In one embodiment, the optical system satisfies the conditional expression: 0< (R61+ R62)/(R61-R62) <2, R61 is a radius of curvature of an object-side surface of the sixth lens at an optical axis, and R62 is a radius of curvature of an image-side surface of the sixth lens at the optical axis. The range of (R61+ R62)/(R61-R62) is reasonably limited, so that the system can be well matched with the main ray incidence angle of the photosensitive chip. If (R61+ R62)/(R61-R62) > 2, the incident angle of the chief ray of the inner view field cannot be made large, and the matching with the incident angle of the chief ray of the photosensitive chip has a problem, so that the requirement of mass production cannot be met.

In one embodiment, the optical system satisfies the conditional expression: 2< FNO <4, FNO being the f-number of the optical system. By defining the range of FNO, it is also possible to achieve a large amount of light flux of the optical system in the case where the optical system has a small head. When the light flux of the optical system is large, the clear imaging effect can be achieved even if the camera shoots in a dark environment. If FNO is too large, on one hand, the diffraction limit is reduced, and on the other hand, the light transmission amount is reduced, so that the shooting in a darker environment is not facilitated.

In one embodiment, the optical system satisfies the conditional expression: 1.25< TTL/f <1.5, wherein TTL is the distance between the object side surface of the first lens and an imaging surface in the optical system on the optical axis, and f is the focal length of the optical system. By reasonably limiting the range of TTL/f, the selectable range of the focal length can be determined under the condition of meeting the requirement of miniaturization, if the range is not met, the maximum field angle of the optical system is larger due to too small focal length, so that longer TTL is required, the maximum field angle of the optical system is smaller due to too large focal length, and the TTL is increased according to the corresponding requirement, so that the miniaturization of the optical system is not facilitated.

In one embodiment, the optical system satisfies the conditional expression: 1.5< TTL/Imgh <1.7, where TTL is an axial distance from an object-side surface of the first lens element to an image plane in the optical system, and Imgh is half an image height corresponding to a maximum field angle of the optical system. By limiting 1.5< TTL/Imgh <1.7, the total length of the system can be ensured to be small under the condition of fixed image surface, and the miniaturization requirement is realized; if TTL/Imgh is more than 1.7, the total length of the system is too long, and miniaturization cannot be realized.

In a second aspect, the present application provides a camera module, including a photosensitive element and the optical system of any one of the foregoing embodiments, where the photosensitive element is located on an image side of the optical system.

In a third aspect, the present application provides a terminal device, including the camera module.

By reasonably configuring the refractive power of the first lens element to the sixth lens element, the surface shapes of the second lens element, the third lens element, the fifth lens element and the sixth lens element in the optical system and limiting cts/sds, the optical system can realize miniaturization, large field angle and high pixel imaging quality, and reduce the size of the opening of the terminal device.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present application, the drawings required to be used in the embodiments or the background art of the present application will be described below.

FIG. 1 is a schematic structural diagram of a first lens provided herein;

FIG. 2 is a schematic diagram of an optical system according to a first embodiment of the present application;

fig. 3 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the first embodiment;

FIG. 4 is a schematic diagram of an optical system provided in a second embodiment of the present application;

FIG. 5 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the second embodiment;

FIG. 6 is a schematic diagram of an optical system provided in a third embodiment of the present application;

fig. 7 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the third embodiment;

FIG. 8 is a schematic diagram of an optical system according to a fourth embodiment of the present application;

fig. 9 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fourth embodiment;

fig. 10 is a schematic structural diagram of an optical system provided in a fifth embodiment of the present application;

fig. 11 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fifth embodiment;

fig. 12 is a schematic structural diagram of an optical system provided in a sixth embodiment of the present application;

fig. 13 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the sixth embodiment;

fig. 14 is a schematic diagram of an optical system provided in the present application applied in a terminal device.

Detailed Description

The embodiments of the present application will be described below with reference to the drawings.

An optical system provided by the present application includes six lenses, which are, in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens.

Specifically, the surface shapes and refractive powers of the six lenses are as follows:

a first lens element with refractive power; the second lens element with positive refractive power has a convex object-side surface and a convex image-side surface at a paraxial region; a third lens element with negative refractive power having a concave image-side surface at paraxial region; a fourth lens element with refractive power; a fifth lens element with positive refractive power having a convex image-side surface at paraxial region; the sixth lens element with negative refractive power has a concave image-side surface at a paraxial region.

The optical system further comprises a diaphragm, and the optical system satisfies the following conditional expression: 0.1< cts/sds <2, cts is the distance between the intersection point of the diaphragm and the optical axis to the intersection point of the object side surface of the first lens and the optical axis, and sds is half of the aperture of the diaphragm.

Specifically, referring to fig. 1, a tangent is drawn at the maximum effective aperture of the object-side surface of the first lens L1, the direction of the tangent is a tangential direction, the direction perpendicular to the optical axis is a vertical optical axis direction, and slope L1S1 is an included angle between the tangential direction at the maximum effective aperture of the object-side surface of the first lens and the vertical optical axis direction, in other words, an inclination angle of the tangential direction at the maximum effective aperture of the object-side surface of the first lens with respect to the vertical optical axis direction is slope L1S 1. Taking the structure of fig. 1 as an example, if the tangential direction is on the left side of the vertical optical axis, then slope l1S1 is negative, and if the tangential direction is on the right side of the vertical optical axis, then slope l1S1 is positive (it should be noted that the directional terms mentioned in the embodiments of the present application, such as "left", "right", etc., refer only to the direction of the drawings, and therefore the directional terms used are intended to better and more clearly describe and understand the embodiments of the present application, and do not indicate or imply that the device or element being referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application).

In one embodiment, the optical system satisfies the conditional expression: 1.5< TTL/Imgh <1.7, where TTL is an axial distance from an object-side surface of the first lens element to an image plane in the optical system, and Imgh is half an image height corresponding to a maximum field angle of the optical system. By limiting TTL/Imgh to be less than 1.7, the total length of the system can be ensured to be small under the condition of fixed image surface, and the miniaturization requirement is realized; if TTL/Imgh is more than 1.7, the total length of the system is too long, and miniaturization cannot be realized.

The present application is described in detail below with reference to six specific examples.

Example one

As shown in fig. 2, a straight line 11 indicates an optical axis, a side of the first lens L1 away from the second lens L2 is an object side 12, and a side of the sixth lens L6 away from the fifth lens L5 is an image side 13. In the optical system provided in this embodiment, the stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the infrared filter element IRCF are arranged in order from the object side 12 to the image side 13.

The first lens element L1 with positive refractive power has a convex object-side surface S1 at a paraxial region, a concave object-side surface S1 at a circumference, a concave image-side surface S2 at a paraxial region, and a convex image-side surface S2 at a circumference.

The second lens element L2 with positive refractive power has a convex object-side surface S3 at a paraxial region and a convex peripheral region, a convex image-side surface S4 at a paraxial region, and a concave image-side surface S4 at a peripheral region, and is made of plastic material.

The third lens element L3 with negative refractive power is made of plastic material, and has a concave object-side surface S5 at a paraxial region, a convex object-side surface S5 at a circumference, and a concave image-side surface S6 at a paraxial region and a concave circumference.

The fourth lens element L4 with negative refractive power has a concave object-side surface S7 at a paraxial region and a concave peripheral region, and has a concave image-side surface S8 at a paraxial region and a concave peripheral region.

The fifth lens element L5 with positive refractive power has a convex object-side surface S9 at a paraxial region and a convex peripheral region, and has an aspheric image-side surface S10 at a paraxial region and a convex peripheral region.

The sixth lens element L6 with negative refractive power is made of plastic material, and has a convex object-side surface S11 at a paraxial region, a concave object-side surface S11 at a circumference, a concave image-side surface S12 at a paraxial region, and a convex image-side surface S12 at a circumference.

The stop STO may be located on the object side of the first lens L1 or between any two adjacent lenses, and the stop STO in the present embodiment is disposed on the object side of the first lens L1 and is disposed away from the first lens L1.

The infrared filter element IRCF is arranged behind the sixth lens L6 and comprises an object side surface S13 and an image side surface S14, the infrared filter element IRCF is used for filtering infrared rays, the rays incident to the image side surface are visible rays, the wavelength of the visible rays is 380nm-780nm, and the infrared filter element IRCF is made of glass.

The image forming surface S15 is a surface on which an image is formed by the light of the subject passing through the optical system.

Table 1a shows a characteristic table of the optical system of the present embodiment in which the radius of curvature in the present embodiment is the radius of curvature of each lens at the paraxial region, the reference wavelength of the focal length is 555nm, and the reference wavelength of the refractive index and the abbe number is 587.56 nm.

TABLE 1a

Wherein f is a focal length of the optical system, FNO is an f-number of the optical system, FOV is a maximum field angle of the optical system, and TTL is a distance on an optical axis from an object-side surface of the first lens to an image plane of the optical system.

In the present embodiment, the object-side surface and the image-side surface of the first lens L1 through the sixth lens L6 are aspheric, and the surface shape of each aspheric lens can be defined by, but is not limited to, the following aspheric formula:

wherein Z is a distance from a corresponding point on the aspherical surface to a plane tangent to the surface vertex, r is a distance from a corresponding point on the aspherical surface to the optical axis, c is a curvature of the aspherical surface vertex, k is a conic constant, and Ai is a coefficient corresponding to the i-th high-order term in the aspherical surface type formula.

Table 1b shows the high-order term coefficients a4, A6, a8, a10, a12, a14, a16, a18, and a20 that can be used for the respective aspherical mirror surfaces S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 in the first embodiment.

TABLE 1b

Fig. 3 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the first embodiment. The longitudinal spherical aberration curve represents the deviation of convergence focuses of light rays with different wavelengths after passing through each lens of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 650.0000nm, 610.0000nm, 555.0000nm, 510.0000nm and 470.0000 nm; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature, wherein S represents sagittal direction, T represents meridional direction, and the reference wavelength of the astigmatism curves is 555.0000 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 555.0000 nm. As can be seen from fig. 3, the optical system according to the first embodiment can achieve good imaging quality.

Example two

As shown in fig. 4, a straight line 11 indicates an optical axis, a side of the first lens L1 away from the second lens L2 is an object side 12, and a side of the sixth lens L6 away from the fifth lens L5 is an image side 13. In the optical system provided in this embodiment, the stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the infrared filter element IRCF are arranged in order from the object side 12 to the image side 13.

The second lens element L2 with positive refractive power has a convex object-side surface S3 at a paraxial region and a convex peripheral region, and has a convex image-side surface S4 at a paraxial region and a convex peripheral region.

The fourth lens element L4 with positive refractive power is made of plastic material, and has a convex object-side surface S7 at a paraxial region, a concave object-side surface S7 at a circumference, a convex image-side surface S8 at a paraxial region, and a concave image-side surface S8 at a circumference.

The fifth lens element L5 with positive refractive power is made of plastic material, and has a concave object-side surface S9 at a paraxial region, a convex object-side surface S9 at a circumference, and an aspheric image-side surface S10 at the paraxial region and the circumferential region.

Table 2a shows a characteristic table of the optical system of the present embodiment in which the radius of curvature in the present embodiment is the radius of curvature of each lens at the paraxial region, the reference wavelength of the focal length is 555nm, and the reference wavelength of the refractive index and the abbe number is 587.56 nm.

TABLE 2a

Table 2b shows high-order coefficient coefficients A4, A6, A8, a10, a12, a14, a16, a18, and a20 that can be used for the respective aspherical mirror surfaces S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 in the second embodiment, wherein the respective aspherical surface types can be defined by the formulas given in the first embodiment.

TABLE 2b

Fig. 5 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the second embodiment. The longitudinal spherical aberration curve represents the deviation of convergence focuses of light rays with different wavelengths after passing through each lens of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 650.0000nm, 610.0000nm, 555.0000nm, 510.0000nm and 470.0000 nm; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature, wherein S represents sagittal direction, T represents meridional direction, and the reference wavelength of the astigmatism curves is 555.0000 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 555.0000 nm. As can be seen from fig. 5, the optical system according to the second embodiment can achieve good imaging quality.

EXAMPLE III

As shown in fig. 6, a straight line 11 indicates an optical axis, a side of the first lens L1 away from the second lens L2 is an object side 12, and a side of the sixth lens L6 away from the fifth lens L5 is an image side 13. In the optical system provided in this embodiment, the stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the infrared filter element IRCF are arranged in order from the object side 12 to the image side 13.

The first lens element L1 with positive refractive power has a concave object-side surface S1 at a paraxial region and a concave peripheral region, and has a convex image-side surface S2 at a paraxial region and a convex peripheral region.

The third lens element L3 with negative refractive power has a convex object-side surface S5 at a paraxial region and a convex peripheral region, a concave image-side surface S6 at a paraxial region, and a convex image-side surface S6 at a peripheral region, and is aspheric.

The fourth lens element L4 with negative refractive power has a concave object-side surface S7 at a paraxial region and a concave peripheral region, a convex image-side surface S8 at a paraxial region, and a concave image-side surface S8 at a peripheral region, and is made of plastic material.

The fifth lens element L5 with positive refractive power is made of plastic material, and has a convex object-side surface S9 at a paraxial region, a concave object-side surface S9 at a circumference, and a convex image-side surface S10 at a paraxial region and a circumference.

Table 3a shows a characteristic table of the optical system of the present embodiment in which the radius of curvature in the present embodiment is the radius of curvature of each lens at the paraxial region, the reference wavelength of the focal length is 555nm, and the reference wavelength of the refractive index and the abbe number is 587.56 nm.

TABLE 3a

Table 3b shows high-order coefficient A4, A6, A8, a10, a12, a14, a16, a18, and a20, which are high-order coefficient coefficients that can be used for each aspherical mirror surface S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 in the third embodiment, wherein each aspherical surface type can be defined by the formula given in the first embodiment.

TABLE 3b

Fig. 7 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the third embodiment. The longitudinal spherical aberration curve represents the deviation of convergence focuses of light rays with different wavelengths after passing through each lens of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 650.0000nm, 610.0000nm, 555.0000nm, 510.0000nm and 470.0000 nm; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature, wherein S represents sagittal direction, T represents meridional direction, and the reference wavelength of the astigmatism curves is 555.0000 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 555.0000 nm. As can be seen from fig. 7, the optical system according to the third embodiment can achieve good image quality.

Example four

As shown in fig. 8, a straight line 11 indicates an optical axis, a side of the first lens L1 away from the second lens L2 is an object side 12, and a side of the sixth lens L6 away from the fifth lens L5 is an image side 13. In the optical system provided in this embodiment, the stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the infrared filter element IRCF are arranged in order from the object side 12 to the image side 13.

The first lens element L1 with negative refractive power has a convex object-side surface S1 at a paraxial region, a concave object-side surface S1 at a circumference, a concave image-side surface S2 at a paraxial region, and a convex image-side surface S2 at a circumference.

Table 4a shows a characteristic table of the optical system of the present embodiment in which the radius of curvature in the present embodiment is the radius of curvature of each lens at the paraxial region, the reference wavelength of the focal length is 555nm, and the reference wavelength of the refractive index and the abbe number is 587.56 nm.

TABLE 4a

Table 4b shows high-order coefficient coefficients A4, A6, A8, a10, a12, a14, a16, a18, and a20 that can be used for the respective aspherical mirror surfaces S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 in the fourth embodiment, wherein the respective aspherical surface types can be defined by the formulas given in the first embodiment.

TABLE 4b

Fig. 9 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fourth embodiment. The longitudinal spherical aberration curve represents the deviation of convergence focuses of light rays with different wavelengths after passing through each lens of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 650.0000nm, 610.0000nm, 555.0000nm, 510.0000nm and 470.0000 nm; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature, wherein S represents sagittal direction, T represents meridional direction, and the reference wavelength of the astigmatism curves is 555.0000 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 555.0000 nm. As can be seen from fig. 9, the optical system according to the fourth embodiment can achieve good image quality.

EXAMPLE five

As shown in fig. 10, a straight line 11 indicates an optical axis, a side of the first lens L1 away from the second lens L2 is an object side 12, and a side of the sixth lens L6 away from the fifth lens L5 is an image side 13. In the optical system provided in this embodiment, the stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the infrared filter element IRCF are arranged in order from the object side 12 to the image side 13.

The first lens element L1 with positive refractive power has a convex object-side surface S1 at a paraxial region, a concave object-side surface S1 at a circumference, and a concave image-side surface S2 at a paraxial region and a concave circumference.

The fourth lens element L4 with negative refractive power is made of plastic material, and has a convex object-side surface S7 at a paraxial region, a concave object-side surface S7 at a circumference, a concave image-side surface S8 at a paraxial region, and a convex image-side surface S8 at a circumference.

Table 5a shows a characteristic table of the optical system of the present embodiment in which the radius of curvature in the present embodiment is the radius of curvature of each lens at the paraxial region, the reference wavelength of the focal length is 555nm, and the reference wavelength of the refractive index and the abbe number is 587.56 nm.

TABLE 5a

Table 5b shows high-order coefficient coefficients A4, A6, A8, a10, a12, a14, a16, a18, and a20 that can be used for the respective aspherical mirror surfaces S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 in the fifth embodiment, wherein the respective aspherical surface types can be defined by the formulas given in the first embodiment.

TABLE 5b

Number of noodles	K	A4	A6	A8	A10
						S1	-5.3372E+00	-5.4730E-02	-2.8221E-01	1.8614E+00	-1.1933E+01
S2	-1.0000E+01	-3.0573E-01	-9.4780E-02	-5.5970E-02	-3.9652E-01
						S3	-1.3117E+01	-1.6924E-01	7.7710E-02	-1.3297E+00	5.0669E+00
S4	-6.5162E+01	-4.1460E-02	-1.1330E+00	5.7237E+00	-1.6020E+01
						S5	6.7180E+00	-8.7590E-02	-1.8933E+00	1.0595E+01	-2.8085E+01
S6	-1.5331E+01	-1.1350E-02	-8.0935E-01	4.1166E+00	-9.2497E+00
						S7	-1.0000E+01	-9.2000E-02	6.4453E-01	-2.5858E+00	5.6815E+00
S8	-8.3780E+00	-2.9054E-01	1.1703E+00	-3.1574E+00	5.1548E+00
						S9	-4.0870E+00	-1.1143E-01	5.5269E-01	-1.3804E+00	1.8315E+00
S10	-9.4434E+00	8.1400E-03	1.5186E-01	-3.3174E-01	2.8484E-01
						S11	4.4823E+00	-2.1041E-01	1.1330E-01	-7.4850E-02	5.2040E-02
S12	-4.5141E+00	-1.4186E-01	1.0550E-01	-6.1170E-02	2.5730E-02
						Number of noodles	A12	A14	A16	A18	A20
S1	4.3636E+01	-9.7592E+01	1.3095E+02	-9.6166E+01	2.9648E+01
						S2	6.7242E+00	-2.0188E+01	2.8164E+01	-1.9521E+01	5.4267E+00
S3	-8.1453E+00	7.5732E+00	-4.4810E+00	1.6004E+00	-2.5899E-01
						S4	2.6803E+01	-2.7357E+01	1.6776E+01	-5.7155E+00	8.3805E-01
S5	4.3672E+01	-4.1691E+01	2.3987E+01	-7.6191E+00	1.0253E+00
						S6	1.2119E+01	-9.7784E+00	4.7675E+00	-1.2802E+00	1.4433E-01
S7	-7.5217E+00	6.1552E+00	-3.0376E+00	8.2883E-01	-9.6280E-02
						S8	-5.2271E+00	3.2922E+00	-1.2428E+00	2.5628E-01	-2.2150E-02
S9	-1.4124E+00	6.3482E-01	-1.5227E-01	1.3610E-02	4.9000E-04
						S10	-8.2840E-02	-2.1970E-02	2.0770E-02	-5.0800E-03	4.3000E-04
S11	-2.2360E-02	5.5800E-03	-8.1000E-04	6.0000E-05	0.0000E+00
						S12	-7.3500E-03	1.3600E-03	-1.5000E-04	1.0000E-05	0.0000E+00

Fig. 11 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fifth embodiment. The longitudinal spherical aberration curve represents the deviation of convergence focuses of light rays with different wavelengths after passing through each lens of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 650.0000nm, 610.0000nm, 555.0000nm, 510.0000nm and 470.0000 nm; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature, wherein S represents sagittal direction, T represents meridional direction, and the reference wavelength of the astigmatism curves is 555.0000 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 555.0000 nm. As can be seen from fig. 11, the optical system according to the fifth embodiment can achieve good image quality.

EXAMPLE six

As shown in fig. 12, a straight line 11 indicates an optical axis, a side of the first lens L1 away from the second lens L2 is an object side 12, and a side of the sixth lens L6 away from the fifth lens L5 is an image side 13. In the optical system provided in this embodiment, the stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the infrared filter element IRCF are arranged in order from the object side 12 to the image side 13.

The sixth lens element L6 with negative refractive power has a concave object-side surface S11 at a paraxial region and a concave peripheral region, a concave image-side surface S12 at a paraxial region, and a convex image-side surface S12 at a peripheral region, and is made of plastic material.

Table 6a shows a characteristic table of the optical system of the present embodiment in which the radius of curvature in the present embodiment is the radius of curvature of each lens at the paraxial region, the reference wavelength of the focal length is 555nm, and the reference wavelength of the refractive index and the abbe number is 587.56 nm.

TABLE 6a

Table 6b shows high-order coefficient A4, A6, A8, a10, a12, a14, a16, a18, and a20, which are high-order coefficient coefficients that can be used for each aspherical mirror surface S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 in the sixth embodiment, wherein each aspherical surface type can be defined by the formula given in the first embodiment.

TABLE 6b

Number of noodles	K	A4	A6	A8	A10
						S1	-5.2278E+00	-4.3030E-02	-1.9774E-01	1.0335E+00	-5.6919E+00
S2	-9.7048E-01	-2.5359E-01	-2.8437E-01	1.3071E+00	-5.4460E+00
						S3	-1.8711E+01	-8.7420E-02	-2.8315E-01	6.1699E-01	-1.7832E+00
S4	-5.0741E+01	1.2430E-02	-1.6414E+00	6.9418E+00	-1.7000E+01
						S5	6.7180E+00	5.2000E-03	-2.0151E+00	8.8159E+00	-2.0436E+01
S6	-1.0718E+01	5.7920E-02	-6.7380E-01	2.5875E+00	-5.1672E+00
						S7	-1.0000E+01	2.9540E-02	2.4827E-01	-1.3839E+00	3.3061E+00
S8	-1.0000E+01	-1.7645E-01	7.4745E-01	-2.1257E+00	3.6018E+00
						S9	-5.2096E+00	-2.3598E-01	6.8691E-01	-1.3051E+00	1.5060E+00
S10	-5.3051E+00	-7.6150E-02	1.9470E-01	-1.7831E-01	-2.0190E-02
						S11	-8.9880E+00	-7.2770E-02	-3.6900E-03	-9.8800E-03	2.9490E-02
S12	-4.6217E+00	-1.0397E-01	6.0500E-02	-2.7190E-02	8.7300E-03
						Number of noodles	A12	A14	A16	A18	A20
S1	1.8459E+01	-3.7879E+01	4.7494E+01	-3.2739E+01	9.4308E+00
						S2	1.5738E+01	-2.7724E+01	2.9107E+01	-1.6689E+01	4.0013E+00
S3	4.7218E+00	-6.5108E+00	4.7487E+00	-1.7950E+00	2.8461E-01
						S4	2.6840E+01	-2.7846E+01	1.8310E+01	-6.8952E+00	1.1318E+00
S5	2.9921E+01	-2.8804E+01	1.7639E+01	-6.1797E+00	9.3765E-01
						S6	6.4196E+00	-5.1724E+00	2.6393E+00	-7.7480E-01	9.9770E-02
S7	-4.6451E+00	4.1047E+00	-2.2299E+00	6.7799E-01	-8.8270E-02
						S8	-3.8404E+00	2.6141E+00	-1.0977E+00	2.5852E-01	-2.6140E-02
S9	-1.0978E+00	5.1246E-01	-1.4850E-01	2.4050E-02	-1.6400E-03
						S10	1.6409E-01	-1.2642E-01	4.4360E-02	-7.6300E-03	5.2000E-04
S11	-1.7630E-02	5.0400E-03	-7.8000E-04	6.0000E-05	0.0000E+00
						S12	-1.9000E-03	2.7000E-04	-2.0000E-05	0.0000E+00	0.0000E+00

Fig. 13 shows a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the sixth embodiment. The longitudinal spherical aberration curve represents the deviation of convergence focuses of light rays with different wavelengths after passing through each lens of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 650.0000nm, 610.0000nm, 555.0000nm, 510.0000nm and 470.0000 nm; the astigmatism curves represent meridional image surface curvature and sagittal image surface curvature, wherein S represents sagittal direction, T represents meridional direction, and the reference wavelength of the astigmatism curves is 555.0000 nm; the distortion curve represents the distortion magnitude values corresponding to different angles of view, and the reference wavelength of the distortion curve is 555.0000 nm. As can be seen from fig. 13, the optical system according to the sixth embodiment can achieve good image quality.

Table 7 shows values of cts/sds, slopL 1S1, f12/f36, (R61+ R62)/(R61-R62), FNO, TTL/f, and TTL/Imgh of the optical systems of the first to sixth embodiments.

TABLE 7

As can be seen from Table 7, each example satisfies: 0.1< cts/sds <2, -20 ° < slope 1S1< -0.5 °, -1< f12/f36< -0.3, 0< (R61+ R62)/(R61-R62) <2, 2< FNO <4, 1.25< TTL/f <1.5, 1.5< TTL/Imgh < 1.7.

Referring to fig. 14, the optical system according to the present application is applied to a camera module 20 in a terminal device 30. The terminal device 30 may be a mobile phone, a tablet computer, an unmanned aerial vehicle, a computer, or the like. The photosensitive element of the camera module 20 is located on the image side of the optical system, and the camera module 20 is assembled inside the terminal device 30.

The application provides a camera module, including photosensitive element and the optical system that this application embodiment provided, photosensitive element is located optical system's image side for incidenting the light on the electron photosensitive element and convert the signal of telecommunication of image into with passing first lens to sixth lens. The electron sensor may be a Complementary Metal Oxide Semiconductor (CMOS) or a Charge-coupled Device (CCD). By installing the optical system in the camera module, the miniaturization, the large field angle and the high-pixel imaging quality can be realized, and the size of the opening hole of the terminal equipment is reduced.

The application also provides a terminal device, and the terminal device comprises the camera module provided by the embodiment of the application. The terminal equipment can be a mobile phone, a tablet personal computer, an unmanned aerial vehicle, a computer and the like. The camera module is installed in the terminal equipment, so that the terminal equipment can realize miniaturization, large field angle and high-pixel imaging quality, and the size of the opening of the terminal equipment is reduced.

The foregoing is a preferred embodiment of the present application, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present application, and these modifications and decorations are also regarded as the protection scope of the present application.

Claims

1. An optical system comprising a plurality of lenses, the plurality of lenses comprising, arranged in order from an object side to an image side:

a first lens element with refractive power;

the second lens element with positive refractive power has a convex object-side surface and a convex image-side surface at a paraxial region;

a third lens element with negative refractive power having a concave image-side surface at paraxial region;

a fourth lens element with refractive power;

a fifth lens element with positive refractive power having a convex image-side surface at paraxial region;

a sixth lens element with negative refractive power having a concave image-side surface at a paraxial region;

the optical system further comprises a diaphragm, and the optical system satisfies the following conditional expression:

0.1<cts/sds<2，

cts is a distance from an intersection point of the diaphragm and the optical axis to an intersection point of the object side surface of the first lens and the optical axis, and sds is half of the aperture of the diaphragm.

2. The optical system according to claim 1, wherein each of the object-side surface and the image-side surface of the first lens to the sixth lens is aspherical.

3. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

-20°<slopeL1S1<-0.5°，

slope l1S1 is the tilt angle at the maximum effective aperture of the object-side face of the first lens.

4. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

-1<f12/f36<-0.3，

f12 is a combined focal length of the first lens and the second lens, and f36 is a combined focal length of the third lens to the sixth lens.

5. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

0<(R61+R62)/(R61-R62)<2，

r61 is a radius of curvature of an object-side surface of the sixth lens element at an optical axis, and R62 is a radius of curvature of an image-side surface of the sixth lens element at the optical axis.

6. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

2<FNO<4，

the FNO is an f-number of the optical system.

7. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

1.25<TTL/f<1.5，

TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane in the optical system, and f is a focal length of the optical system.

8. The optical system according to claim 1, wherein the optical system satisfies the conditional expression:

1.5<TTL/Imgh<1.7，

TTL is a distance on an optical axis from an object-side surface of the first lens element to an image plane in the optical system, and ImgH is half of an image height corresponding to a maximum field angle of the optical system.

9. A camera module comprising a photosensitive element and the optical system of any one of claims 1 to 8, wherein the photosensitive element is located on the image side of the optical system.

10. A terminal device characterized by comprising the camera module according to claim 9.