CN114815146B - Optical system, image capturing module, electronic device and carrier - Google Patents
Optical system, image capturing module, electronic device and carrier Download PDFInfo
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- CN114815146B CN114815146B CN202210236784.2A CN202210236784A CN114815146B CN 114815146 B CN114815146 B CN 114815146B CN 202210236784 A CN202210236784 A CN 202210236784A CN 114815146 B CN114815146 B CN 114815146B
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- 238000012634 optical imaging Methods 0.000 abstract description 6
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- 230000009286 beneficial effect Effects 0.000 description 10
- 238000000034 method Methods 0.000 description 10
- 238000001746 injection moulding Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 239000006185 dispersion Substances 0.000 description 6
- 201000009310 astigmatism Diseases 0.000 description 5
- 239000011521 glass Substances 0.000 description 5
- 238000003754 machining Methods 0.000 description 4
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
- G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
- G02B13/004—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having four lenses
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B30/00—Camera modules comprising integrated lens units and imaging units, specially adapted for being embedded in other devices, e.g. mobile phones or vehicles
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Abstract
The embodiment of the disclosure discloses an optical system, an image capturing module, an electronic device and a carrier, wherein the optical system includes a first lens element, a second lens element, a third lens element and a fourth lens element arranged in order from an object side to an image side along an optical axis, the first lens element has positive refractive power, the object side is convex at a paraxial region, the image side is convex at the paraxial region, the second lens element has positive refractive power, the object side is concave at the paraxial region, the image side is convex at the paraxial region, the third lens element has positive refractive power, the object side is concave at the paraxial region, the image side is convex at the paraxial region, the fourth lens element has negative refractive power, the object side is convex at the paraxial region and the image side is concave at the paraxial region; the effective focal length of the optical system is f, the distance from the object side surface of the first lens to the imaging surface on the optical axis is TTL, and f and TTL satisfy the conditional expression: 0.5 < f/TTL < 0.7. The design can effectively reduce the possibility of changing the angle of view caused by temperature so as to improve the optical imaging quality of the optical system.
Description
Technical Field
Embodiments of the present disclosure relate to the field of optical imaging technologies, and in particular, to an optical system, an image capturing module, an electronic device, and a carrier.
Background
In the related art, a lens on the market is easy to change the angle of view of the lens due to the change of the external temperature, thereby affecting the optical imaging quality of the lens. Therefore, how to effectively reduce the influence of the change of the angle of view of the lens due to the influence of temperature has become a urgent problem to be solved.
Disclosure of Invention
The embodiment of the specification provides an optical system, an image capturing module, electronic equipment and a carrier, which can effectively reduce the possibility of changing the angle of view caused by temperature so as to improve the optical imaging quality of the optical system.
In a first aspect, embodiments of the present description provide an optical system; the optical system comprises a first lens element, a second lens element, a third lens element and a fourth lens element which are arranged in order from an object side to an image side along an optical axis of the optical system, wherein the first lens element has positive refractive power, the object side of the first lens element is convex at a paraxial region, the image side of the first lens element is convex at a paraxial region, the second lens element has positive refractive power, the object side of the second lens element is concave at a paraxial region, the image side of the second lens element is convex at a paraxial region, the third lens element has positive refractive power, the object side of the third lens element is concave at a paraxial region, the image side of the third lens element is convex at a paraxial region, the fourth lens element has negative refractive power, the object side of the fourth lens element is convex at a paraxial region, and the image side of the fourth lens element is concave at a paraxial region; the effective focal length of the optical system is f, the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis is TTL, and f and TTL satisfy the conditional expression:
0.5＜f/TTL＜0.7。
Based on the optical system of the embodiment of the present disclosure, the object-side surface of the third lens element is designed to be concave at the paraxial region, and the image-side surface of the third lens element is designed to be convex at the paraxial region, i.e., the third lens element is designed to be in a meniscus configuration, so that the curvature of field and astigmatism of the optical system can be effectively corrected; by designing the fourth lens with negative refractive power, the incidence angle of the chief ray can be adjusted while the aberration of the optical system is corrected, so that the chief ray can be better matched with the image sensor; by designing the refractive powers of the first lens element, the second lens element, the third lens element and the fourth lens element to be positive and negative, the lens element can uniformly take on the incidence deflection angle of light rays, so as to effectively correct the aberration of the optical system. When f/TTL is more than 0.5 and less than 0.7, the ratio of f to TTL is reasonably configured by controlling f and TTL through parameter design, so that the optical system has compact structure, the internal overall layout of the optical system such as lenses is natural, the miniaturized design of the optical system can be realized, the lens with different refractive power and focal length can be effectively utilized to realize the receiving and imaging of weak spots through the configuration mode, the overall distortion rate of the optical system can be ensured to be smaller, the overall performance change in the range of-20 ℃ to 60 ℃ is smaller, and the temperature stability performance of the optical system can be effectively ensured; when f/TTL is less than or equal to 0.5, the structure of the optical system is loose, which is not beneficial to the miniaturization design and the attractive degree of the optical system; when f/TTL is more than or equal to 0.7, the tolerance of the optical system is sensitive, the assembly of the optical system is not facilitated, and the temperature stability of the optical system is not facilitated.
In some embodiments, the focal length of the first lens is f1, where f1 and f satisfy the following conditional expression:
1.0＜f1/f＜2.0。
based on the embodiment, when f1/f is more than 1.0 and less than 2.0, the ratio of f1 to f is reasonably configured by controlling f1 and f through parameter design, and the incidence angle of the chief ray is reasonably distributed, so that the aberration of the optical system is favorably corrected; when f1/f is less than or equal to 1.0, the deflection angle of the chief ray born by the first lens is overlarge, so that the tolerance of the first lens is sensitive, the processing precision requirement of the first lens is high, and the processing and the manufacturing of the first lens are not facilitated; when f1/f is more than or equal to 2.0, the deflection angle of the principal ray born by the first lens is too small, which is not beneficial to the first lens to share the temperature stability of the optical system.
In some embodiments, the focal length of the second lens is f2, wherein f2 and f satisfy the following conditional expression:
1.5＜f2/f＜2.6。
based on the embodiment, when f2/f is more than 1.5 and less than 2.6, the ratio of f2 to f is reasonably configured by controlling f2 and f through parameter design, and at the moment, the focal power of the second lens is reasonably distributed, so that the compactness of the optical system is ensured, and the aberration of the optical system is favorably corrected; when f2/f is less than or equal to 1.5, the tolerance of the second lens is sensitive, so that the processing precision requirement of the second lens is high, and the processing and manufacturing of the second lens are not facilitated; when f2/f is more than or equal to 2.6, the pressure for causing the third lens and the fourth lens to bear deflection of the principal ray at the rear part is larger, which is not beneficial to balance of the whole aberration of the optical system.
In some embodiments, the focal length of the third lens is f3, wherein f3 and f satisfy the following conditional expression:
1.6＜f3/f＜2.8。
based on the embodiment, when f3/f is more than 1.6 and less than 2.8, the ratio of f3 to f is reasonably configured by controlling f3 and f through parameter design, and at the moment, the focal power of the third lens is reasonably distributed, so that the compactness of the optical system is ensured, and the aberration of the optical system is favorably corrected; when f3/f is less than or equal to 1.6, the tolerance of the third lens is sensitive, so that the machining precision requirement of the third lens is high, and the machining and manufacturing of the third lens are not facilitated; when f3/f is more than or equal to 2.8, the pressure for causing the fourth lens to bear the deflection of the principal ray is larger, which is not beneficial to the balance of the whole aberration of the optical system.
In some embodiments, the focal length of the fourth lens is f4, wherein f4 and f satisfy the following conditional expression:
-5.0＜f4/f＜-2.0。
based on the embodiment, when f4/f is less than-5.0 and less than-2.0, the ratio of f4 to f is reasonably configured by controlling f4 and f through parameter design, and at the moment, the focal power of the fourth lens is reasonably distributed, so that the structural compactness of the optical system is ensured, and the aberration of the optical system can be well compensated; when f4/f is less than or equal to-5.0, the fourth lens has limited capability of balancing the aberration of the optical system, which is unfavorable for the temperature stability of the optical system; when f4/f is more than or equal to-2.0, the tolerance of the fourth lens is sensitive, and the balance of the whole aberration of the optical system is not facilitated.
In some embodiments, the radius of curvature of the object-side surface of the first lens element at the paraxial region is R11, and the radius of curvature of the image-side surface of the first lens element at the paraxial region is R12, wherein R11 and R12 satisfy the following condition:
-1.5＜(R11-R12)/(R11+R12)＜-0.5。
based on the above embodiment, when-1.5 < (R11-R12)/(R11+R12) < -0.5, the ratio of (R11-R12) to (R11+R12) is reasonably configured by controlling R11 and R12 through parameter design, and the appearance of the first lens is attractive, easy to process and detect, the advanced aberration of the optical system can be well restrained and balanced, and the surface tolerance requirement of the first lens is proper, so that each index requirement of the optical system can be well met, and the assembly of the first lens is facilitated; when (R11-R12)/(R11+R12) is less than or equal to-1.5 or (R11-R12)/(R11+R12) is more than or equal to-0.5, the injection molding of the first lens is not facilitated, the tolerance of the first lens is sensitive, the assembly difficulty of the first lens is high, and the optical system is not facilitated to obtain excellent imaging quality and temperature stability.
In some embodiments, the object-side surface of the second lens element has a radius of curvature R21 at a paraxial region, and the image-side surface of the second lens element has a radius of curvature R22 at a paraxial region, wherein R21 and R22 satisfy the following condition:
0.2＜(R21-R22)/(R21+R22)＜0.6。
Based on the above embodiment, when 0.2 < (r21-r22)/(r21+r22) < 0.6, the ratio of (r21-r22) to (r21+r22) is reasonably configured by controlling R21 and R22 through parameter design, and at this time, the second lens has attractive appearance, is easy to process and detect, can better inhibit and balance the advanced aberration of the optical system, and has appropriate surface tolerance requirement, can better meet each index requirement of the optical system, and is beneficial to the assembly of the second lens; when (R21-R22)/(R21+R22) is less than or equal to 0.2 or (R21-R22)/(R21+R22) is more than or equal to 0.6, the injection molding of the second lens is not facilitated, the tolerance of the second lens is sensitive, the assembly difficulty of the second lens is high, and the optical system is not facilitated to obtain excellent imaging quality and temperature stability.
In some embodiments, the radius of curvature of the object-side surface of the third lens element at the paraxial region is R31, and the radius of curvature of the image-side surface of the third lens element at the paraxial region is R32, wherein R31 and R32 satisfy the following condition:
-0.1＜(R31-R32)/(R31+R32)＜-0.01。
based on the above embodiment, when-0.1 < (r31-r32)/(r31+r32) < -0.01, the ratio of (r31-r32) to (r31+r32) is reasonably configured by controlling R31 and R32 through parameter design, and at this time, the appearance of the third lens is attractive, easy to process and detect, and can better inhibit and balance the advanced aberration of the optical system, and the surface tolerance requirement of the third lens is suitable, so that each index requirement of the optical system can be better satisfied, and the assembly of the third lens is facilitated; when (R31-R32)/(R31+R32) is less than or equal to-0.1 or (R31-R32)/(R31+R32) is more than or equal to-0.01, the injection molding of the third lens is not facilitated, the tolerance of the third lens is more sensitive, the assembly difficulty of the third lens is high, and the optical system is not facilitated to obtain excellent imaging quality and temperature stability.
In some embodiments, the radius of curvature of the object-side surface of the fourth lens element at the paraxial region is R41, and the radius of curvature of the image-side surface of the fourth lens element at the paraxial region is R42, wherein R41 and R42 satisfy the following condition:
0.1＜(R41-R42)/(R41+R42)＜0.2。
based on the above embodiment, when 0.1 < (R41-R42)/(R41+R 42) < 0.2, the ratio of (R41-R42) to (R41+R 42) is reasonably configured by controlling the design of parameters R41 and R42, and the appearance of the fourth lens is attractive, easy to process and detect, the advanced aberration of the optical system can be well restrained and balanced, and the surface tolerance requirement of the fourth lens is proper, so that each index requirement of the optical system can be well met, and the assembly of the fourth lens is facilitated; when (R41-R42)/(R41+R42) is less than or equal to 0.1 or (R41-R42)/(R41+R42) is more than or equal to 0.2, the injection molding of the fourth lens is not facilitated, the tolerance of the fourth lens is sensitive, the assembly difficulty of the fourth lens is high, and the optical system is not facilitated to obtain excellent imaging quality and temperature stability.
In some embodiments, the first lens has a thickness n1 at the optical axis, wherein n1 satisfies the following condition:
-0.00001＜dn1/dt＜0.0。
based on the embodiment, when dn1/dt is less than 0.0 and is less than-0.00001, the ratio of dn1 to dt is reasonably configured by controlling n1 through parameter design, and the temperature stability of the optical system in the range of-20 ℃ to 60 ℃ can be ensured; when dn1/dt is less than or equal to-0.00001, the temperature stability of the optical system in the range of-20 ℃ to 60 ℃ cannot be ensured at the moment; when dn1/dt is more than or equal to 0.0, the current refractive material cannot be realized.
In a second aspect, an embodiment of the present disclosure provides an image capturing module, where the image capturing module includes an image sensor and the optical system, and the image sensor is disposed on an image side of the optical system.
Based on the image capturing module in the embodiment of the specification, the image capturing module with the optical system meets the design of small volume and high pixels, and meanwhile, the image capturing module has good temperature stability within the range of-20 ℃ to 60 ℃ so that the image capturing module has good imaging quality.
In a third aspect, an embodiment of the present disclosure provides an electronic device, where the electronic device includes a mounting structure and the image capturing module, and the image capturing module is disposed on the mounting structure.
Based on the electronic equipment in the embodiment of the specification, the electronic equipment with the image capturing module meets the design of small volume and high pixels, and meanwhile, the electronic equipment has good temperature stability within the range of-20 ℃ to 60 ℃ so that the electronic equipment has good imaging quality.
In a fourth aspect, an embodiment of the present disclosure provides a carrier, where the carrier includes a connection structure and the electronic device, and the electronic device is disposed on the connection structure.
Based on the carrier in the embodiment of the specification, the carrier with the image capturing module meets the design of small volume and high pixels, and meanwhile, the carrier has good temperature stability within the range of-20 ℃ to 60 ℃ so that the carrier has good imaging quality.
Based on the optical system, the image capturing module, the electronic device and the carrier of the embodiments of the present disclosure, by designing the object side surface of the third lens element to be concave at the paraxial region and the image side surface of the third lens element to be convex at the paraxial region, that is, designing the third lens element to be in a meniscus structure, the field curvature and astigmatism of the optical system can be effectively corrected; by designing the fourth lens with negative refractive power, the incidence angle of the chief ray can be adjusted while the aberration of the optical system is corrected, so that the chief ray can be better matched with the image sensor; by designing the refractive powers of the first lens element, the second lens element, the third lens element and the fourth lens element to be positive and negative, the lens element can uniformly take on the incidence deflection angle of light rays, so as to effectively correct the aberration of the optical system. When f/TTL is more than 0.5 and less than 0.7, the ratio of f to TTL is reasonably configured by controlling f and TTL through parameter design, so that the optical system has compact structure, the internal overall layout of the optical system such as lenses is natural, the miniaturized design of the optical system can be realized, the lens with different refractive power and focal length can be effectively utilized to realize the receiving and imaging of weak spots through the configuration mode, the overall distortion rate of the optical system can be ensured to be smaller, the overall performance change in the range of-20 ℃ to 60 ℃ is smaller, and the temperature stability performance of the optical system can be effectively ensured; when f/TTL is less than or equal to 0.5, the structure of the optical system is loose, which is not beneficial to the miniaturization design and the attractive degree of the optical system; when f/TTL is more than or equal to 0.7, the tolerance of the optical system is sensitive, the assembly of the optical system is not facilitated, and the temperature stability of the optical system is not facilitated.
Drawings
In order to more clearly illustrate the embodiments of the present description or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 schematically shows a schematic configuration of an optical system in a first embodiment of the present specification;
FIG. 2 schematically shows the MFT at 1/4Ny, 1/2Ny, and Ny for an optical system in embodiment one of the present specification;
FIG. 3 schematically shows a Through-Focus-MTF diagram of an optical system having a frequency of 43.0000p/mm in the first embodiment of the present specification;
fig. 4A to 4B schematically show an astigmatic curve diagram and a distortion curve diagram of an optical system according to the first embodiment of the present disclosure, respectively;
fig. 5 schematically shows a relative illuminance curve of the optical system in the first embodiment of the present specification;
fig. 6 schematically shows a schematic configuration of an optical system in a second embodiment of the present specification;
FIG. 7 schematically shows the MFT at 1/4Ny, 1/2Ny, and Ny for an optical system in embodiment two of the present specification;
FIG. 8 schematically shows a Through-Focus-MTF diagram of an optical system having a frequency of 43.0000p/mm in a second embodiment of the present specification;
fig. 9A to 9B schematically show an astigmatic curve diagram and a distortion curve diagram of an optical system provided in the second embodiment of the present specification, respectively;
fig. 10 schematically shows a relative illuminance curve of an optical system in the second embodiment of the present specification;
fig. 11 schematically illustrates a structural diagram of an image capturing module according to an embodiment of the present disclosure;
fig. 12 schematically shows a structural diagram of the electronic device in the embodiment of the present disclosure when the electronic device is a vehicle-mounted camera;
fig. 13 schematically shows a schematic configuration of an automobile as the vehicle in the embodiment of the present disclosure.
Reference numerals: 100. an optical system; 110. a first lens; 120. a second lens; 130. a third lens; 140. a fourth lens; 150. a light filter; s1, an object side surface of a first lens; s2, an image side surface of the first lens; s3, the object side surface of the second lens; s4, an image side surface of the second lens; s5, the object side surface of the third lens is provided; s6, an image side surface of the third lens; s7, an object side surface of the fourth lens; s8, an image side surface of the fourth lens is provided; s9, a first surface; s10, a second surface; s11, an imaging surface; STO and diaphragm; 200. an image capturing module; 210. an image sensor; 300. an electronic device; 310. a mounting structure; 400. and a carrier.
Detailed Description
The aberrations involved in the embodiments of the present specification are explained first below; aberration (aberration) refers to the deviation of the result of non-paraxial ray tracing from the ideal state of gaussian optics (first order approximation theory or paraxial rays) in an optical lens group, which is inconsistent with the result of paraxial ray tracing. Aberrations fall into two main categories: chromatic aberration (chromatic aberration, or chromatic aberration) and monochromatic aberration (monochromatic aberration). Chromatic aberration is an aberration generated by different refractive indexes of light with different wavelengths passing through a lens because the refractive index of a lens material is a function of the wavelength, and can be divided into position chromatic aberration and magnification chromatic aberration. Chromatic aberration is a dispersion phenomenon, which is a phenomenon in which the speed of light or refractive index in a medium varies with the wavelength of an optical wave, and dispersion in which the refractive index of light decreases with an increase in wavelength may be referred to as normal dispersion, while dispersion in which the refractive index increases with an increase in wavelength may be referred to as negative dispersion (or negative anomalous dispersion). Monochromatic aberrations refer to aberrations that occur even when highly monochromatic light, and are classified into two categories, namely "blurring imaging" and "deforming imaging" according to the effect produced; the former category includes spherical aberration (spherical aberration), astigmatism (astigmatism), and the latter category includes field curvature (field curvature), distortion (aberration), and the like. The aberration also includes coma, which is a single-color conical light beam emitted from an off-axis object point outside the principal axis to the optical lens group, and after being refracted by the optical lens group, the coma cannot be formed into a clear point at an ideal plane, but is formed into a comet-shaped light spot dragging a bright tail.
In the related art, a lens on the market is easy to change the angle of view of the lens due to the change of the external temperature, thereby affecting the optical imaging quality of the lens. Therefore, how to effectively reduce the influence of the change of the angle of view of the lens due to the influence of temperature has become a urgent problem to be solved.
In order to solve the above-mentioned problems, referring to fig. 1-10, a first aspect of the embodiments of the present disclosure provides an optical system 100 capable of effectively reducing the possibility of changing the angle of view due to temperature, so as to improve the optical imaging quality of the optical system 100.
As shown in fig. 1, the optical system 100 includes a first lens 110, a second lens 120, a third lens 130, and a fourth lens 140 disposed in order from an object side to an image side along an optical axis of the optical system 100.
The first lens element 110 with positive refractive power has a convex object-side surface S1 at a paraxial region and a convex image-side surface S2 at a paraxial region of the first lens element 110;
the second lens element 120 with positive refractive power has a concave object-side surface S3 at a paraxial region and a convex image-side surface S4 at a paraxial region of the second lens element 120.
The third lens element 130 with positive refractive power has a concave object-side surface S5 at a paraxial region and a convex image-side surface S6 at a paraxial region of the third lens element 130.
The fourth lens element 140 with negative refractive power has a convex object-side surface S7 at a paraxial region and a concave image-side surface S8 at a paraxial region of the fourth lens element 140.
Further, the effective focal length of the optical system 100 is f, the distance from the object side surface S1 of the first lens element 110 to the imaging surface S11 of the optical system 100 on the optical axis is TTL, and f and TTL satisfy the following conditional expression: 0.5 < f/TTL < 0.7. Specifically, the f/TTL can take on a value of 0.600 or 0.580.
In summary, by designing the object-side surface S5 of the third lens element 130 to be concave at the paraxial region, the image-side surface S6 of the third lens element 130 to be convex at the paraxial region, i.e., designing the third lens element 130 to be in a meniscus configuration, the curvature of field and astigmatism of the optical system 100 can be effectively corrected; by designing the fourth lens element 140 with negative refractive power, the aberration of the optical system 100 can be corrected, and the incident angle of the chief ray can be adjusted, so that the chief ray can be better matched with the image sensor 210; by designing the refractive powers of the first lens element 110, the second lens element 120, the third lens element 130 and the fourth lens element 140 to be positive and negative, the lens element can uniformly take on the incidence angle of the light beam, so as to effectively correct the aberration of the optical system 100. When f/TTL is more than 0.5 and less than 0.7, the ratio of f to TTL is reasonably configured by controlling f and TTL through parameter design, so that the optical system 100 has compact structure, the internal overall layout of the optical system 100 such as lenses is natural, the miniaturized design of the optical system 100 can be realized, through the configuration mode, the lens with different refractive power and focal length can be effectively utilized to realize the receiving and imaging of weak spots, meanwhile, the overall aberration rate of the optical system 100 can be ensured to be smaller, the overall performance change in the range of-20 ℃ to 60 ℃ is smaller, and the temperature stability performance of the optical system 100 can be effectively ensured; when f/TTL is less than or equal to 0.5, the structure of the optical system 100 is loose, which is not beneficial to the miniaturization design and the aesthetic degree of the optical system 100; when f/TTL is greater than or equal to 0.7, the tolerance of the optical system 100 is sensitive, which is unfavorable for the assembly of the optical system 100 and the temperature stability of the optical system 100.
Further, as shown in fig. 1, in some embodiments, the focal length of the first lens 110 is f1, where f1 and f satisfy the following conditional expression: 1.0 < f1/f < 2.0. Specifically, the value of f1/f can be 1.613 or 1.703. In the design, when f1/f is more than 1.0 and less than 2.0, the ratio of f1 to f is reasonably configured by controlling f1 and f through parameter design, and the incidence angle of the chief ray is reasonably distributed, thereby being beneficial to correcting the aberration of the optical system 100; when f1/f is less than or equal to 1.0, the deflection angle of the principal ray born by the first lens 110 is too large, so that the tolerance of the first lens 110 is sensitive, the processing precision requirement of the first lens 110 is high, and the processing and manufacturing of the first lens 110 are not facilitated; when f1/f is greater than or equal to 2.0, the deflection angle of the chief ray borne by the first lens 110 is too small, which is not beneficial for the first lens 110 to share the temperature stability of the optical system 100.
Further, as shown in fig. 1, in some embodiments, the focal length of the second lens 120 is f2, where f2 and f satisfy the following conditional expression: 1.5 < f2/f < 2.6. Specifically, the value of f2/f can be 2.115 or 2.069. In the design, when f2/f is more than 1.5 and less than 2.6, the ratio of f2 to f is reasonably configured by controlling f2 and f through parameter design, and at the moment, the focal power of the second lens 120 is reasonably distributed, so that the compactness of the optical system 100 is ensured, and the aberration of the optical system 100 is favorably corrected; when f2/f is less than or equal to 1.5, the tolerance of the second lens 120 is sensitive, so that the processing precision requirement of the second lens 120 is high, and the processing and manufacturing of the second lens 120 are not facilitated; when f2/f is equal to or greater than 2.6, the pressure of the third lens 130 and the fourth lens 140 at the rear to bear the deflection of the principal ray is larger, which is not beneficial to the balance of the aberration of the whole optical system 100.
Further, as shown in fig. 1, in some embodiments, the focal length of the third lens 130 is f3, where f3 and f satisfy the following conditional expression: 1.6 < f3/f < 2.8. Specifically, the value of f3/f can be 2.220 or 2.362. In the design, when f3/f is more than 1.6 and less than 2.8, the ratio of f3 to f is reasonably configured by controlling f3 and f through parameter design, and at the moment, the focal power of the third lens 130 is reasonably distributed, so that the compactness of the optical system 100 is ensured, and the aberration of the optical system 100 is favorably corrected; when f3/f is less than or equal to 1.6, the tolerance of the third lens 130 is sensitive, so that the machining precision requirement of the third lens 130 is high, and the machining and manufacturing of the third lens 130 are not facilitated; when f3/f is equal to or greater than 2.8, the pressure of the fourth lens 140 at the rear to take over the principal ray deflection is larger, which is unfavorable for the balance of the aberration of the optical system 100 as a whole.
Further, as shown in fig. 1, in some embodiments, the focal length of the fourth lens 140 is f4, where f4 and f satisfy the following conditional expression: -5.0 < f4/f < -2.0. Specifically, the value of f4/f can be-3.532 or-4.234. In the design, when f4/f is less than-5.0 and less than-2.0, f4 and f are controlled through parameter design to enable the ratio of f4 to f to be reasonably configured, at the moment, the focal power of the fourth lens 140 is reasonably distributed, the structural compactness of the optical system 100 is ensured, and the aberration of the optical system 100 can be well compensated; when f4/f is not more than-5.0, the fourth lens 140 is limited in its ability to balance the aberration of the optical system 100, which is detrimental to the temperature stability of the optical system 100; when f4/f is equal to-2.0, the tolerance of the fourth lens 140 is sensitive, which is detrimental to the balance of the aberration of the optical system 100 as a whole.
Further, as shown in fig. 1, in some embodiments, the radius of curvature of the object-side surface S1 of the first lens element 110 at the paraxial region is R11, and the radius of curvature of the image-side surface S2 of the first lens element 110 at the paraxial region is R12, wherein R11 and R12 satisfy the following conditional expression: -1.5 < (R11-R12)/(R11+R12) < -0.5. Specifically, (R11-R12)/(R11+R12) may have a value of-0.996 or-0.956. In the design, when-1.5 < (R11-R12)/(R11+R12) < -0.5, the ratio of (R11-R12) to (R11+R12) is reasonably configured by controlling R11 and R12 through parameter design, and the appearance of the first lens 110 is attractive, easy to process and detect, the advanced aberration of the optical system 100 can be well restrained and balanced, the surface type tolerance requirement of the first lens 110 is proper, the various index requirements of the optical system 100 can be well met, and the assembly of the first lens 110 is facilitated; when (R11-R12)/(R11+R12) is less than or equal to-1.5 or (R11-R12)/(R11+R12) is more than or equal to-0.5, the injection molding of the first lens 110 is not facilitated, the tolerance of the first lens 110 is sensitive, the assembly difficulty of the first lens 110 is high, and the optical system 100 is not facilitated to obtain excellent imaging quality and temperature stability.
Further, as shown in fig. 1, in some embodiments, the radius of curvature of the object-side surface S3 of the second lens element 120 at the paraxial region is R21, and the radius of curvature of the image-side surface S4 of the second lens element 120 at the paraxial region is R22, wherein R21 and R22 satisfy the following conditional expression: 0.2 < (R21-R22)/(R21+R22) < 0.6. Specifically, (R21-R22)/(R21+R22) may have a value of 0.363 or 0.394. In the design, when 0.2 < (R21-R22)/(R21+R22) < 0.6, the ratio of (R21-R22) to (R21+R22) is reasonably configured by controlling R21 and R22 through parameter design, and the appearance of the second lens 120 is attractive, easy to process and detect, the advanced aberration of the optical system 100 can be well restrained and balanced, the surface tolerance requirement of the second lens 120 is proper, the various index requirements of the optical system 100 can be well met, and the assembly of the second lens 120 is facilitated; when (R21-R22)/(R21+R22) is less than or equal to 0.2 or (R21-R22)/(R21+R22) is more than or equal to 0.6, the injection molding of the second lens 120 is not facilitated, the tolerance of the second lens 120 is more sensitive, the assembly difficulty of the second lens 120 is high, and the optical system 100 is not facilitated to obtain excellent imaging quality and temperature stability.
Further, as shown in fig. 1, in some embodiments, the radius of curvature of the object-side surface S5 of the third lens element 130 at the paraxial region is R31, the radius of curvature of the image-side surface S6 of the third lens element 130 at the paraxial region is R32, and the R31 and R32 satisfy the following conditional expression: -0.1 < (R31-R32)/(R31+R32) < -0.01. Specifically, (R31-R32)/(R31+R32) may have a value of-0.033 or-0.037. In the design, when-0.1 < (R31-R32)/(R31+R32) < -0.01, the ratio of (R31-R32) to (R31+R32) is reasonably configured by controlling R31 and R32 through parameter design, and the appearance of the third lens 130 is attractive, easy to process and detect, the advanced aberration of the optical system 100 can be well restrained and balanced, the surface type tolerance requirement of the third lens 130 is proper, the various index requirements of the optical system 100 can be well met, and the assembly of the third lens 130 is facilitated; when (R31-R32)/(R31+R32) is less than or equal to-0.1 or (R31-R32)/(R31+R32) is more than or equal to-0.01, the injection molding of the third lens 130 is not facilitated, the tolerance of the third lens 130 is more sensitive, the assembly difficulty of the third lens 130 is high, and the optical system 100 is not facilitated to obtain excellent imaging quality and temperature stability.
Further, as shown in fig. 1, in some embodiments, the radius of curvature of the object-side surface S7 of the fourth lens element 140 at the paraxial region is R41, and the radius of curvature of the image-side surface S8 of the fourth lens element 140 at the paraxial region is R42, wherein R41 and R42 satisfy the following conditional expression: 0.1 < (R41-R42)/(R41+R42) < 0.2. Specifically, (R41-R42)/(R41 + R42) may have a value of 0.186 or 0.167. In the design, when 0.1 < (R41-R42)/(R41+R 42) < 0.2, the ratio of (R41-R42) to (R41+R 42) is reasonably configured by controlling R41 and R42 through parameter design, and the appearance of the fourth lens 140 is attractive, easy to process and detect, the high-grade aberration of the optical system 100 can be well restrained and balanced, the surface tolerance requirement of the fourth lens 140 is proper, the various index requirements of the optical system 100 can be well met, and the assembly of the fourth lens 140 is facilitated; when (R41-R42)/(R41+R42) is less than or equal to 0.1 or (R41-R42)/(R41+R42) is more than or equal to 0.2, the injection molding of the fourth lens 140 is not facilitated, the tolerance of the fourth lens 140 is more sensitive, the assembly difficulty of the fourth lens 140 is high, and the optical system 100 is not facilitated to obtain excellent imaging quality and temperature stability.
Further, as shown in fig. 1, in some embodiments, the thickness of the first lens 110 at the optical axis is n1, where n1 satisfies the following formula: -0.00001 < dn1/dt < 0.0. Specifically, the value of dn1/dt may be-6.26E-6. In the design, when dn1/dt is less than 0.0 and minus 0.00001, the ratio of dn1 to dt is reasonably configured by controlling n1 through parameter design, and the temperature stability of the optical system 100 in the range of minus 20 ℃ to 60 ℃ can be ensured; when dn1/dt is less than or equal to-0.00001, the temperature stability of the optical system 100 in the range of-20 ℃ to 60 ℃ cannot be ensured at this time; when dn1/dt is more than or equal to 0.0, the current refractive material cannot be realized.
Further, to reduce stray light in the optical system 100 to improve the imaging quality of the optical system 100, the optical system 100 further includes an aperture stop STO, which may be an aperture stop STO or a field stop STO, where the aperture stop STO is used in the embodiment of the present disclosure. The stop STO is located between the object side of the optical system 100 and the imaging surface S11, and may be provided at any position between the object side of the optical system 100 and the object side surface S1 of the first lens 110, between any two lenses of the first lens 110 to the fourth lens 140, and between the image side surface S8 of the fourth lens 140 and the imaging surface S11 of the optical system 100, for example; for cost saving, a stop STO may be provided on the object side or image side of either lens. In the embodiment of the present disclosure, the stop STO is disposed on the object side S1 of the first lens element 110, and in this design, the risk of ghost image can be effectively reduced by disposing the stop STO, so as to improve the imaging quality of the optical system 100.
It should be noted that, the object side surface of the lens refers to a surface of the lens facing the object plane, the image side surface of the lens refers to a surface of the lens facing the image plane, for example, the object side surface S1 of the first lens 110 refers to a surface of the first lens 110 facing (near) the object side, and the image side surface S2 of the first lens 110 refers to a surface of the first lens 110 facing (near) the image side. The positive radius of curvature of the object side surface or the image side surface of each lens at the optical axis indicates that the object side surface or the image side surface of the lens protrudes towards the object plane, and the negative radius of curvature of the object side surface or the image side surface of each lens at the optical axis indicates that the object side surface or the image side surface of the lens protrudes towards the image plane.
Further, in order to correct the aberration of the optical system 100 to improve the imaging quality of the optical system 100, at least one of the object-side surfaces or the image-side surfaces of the first lens element 110, the second lens element 120, the third lens element 130 and the fourth lens element 140 is aspheric, for example, the object-side surface S1 of the first lens element 110 may be aspheric, and the object-side surface S3 of the second lens element 120 may be aspheric. In the embodiment of the present disclosure, the object-side surface S1 of the first lens element 110, the image-side surface S2 of the first lens element 110, the object-side surface S3 of the second lens element 120, the image-side surface S4 of the second lens element 120, the object-side surface S5 of the third lens element 130, the image-side surface S6 of the third lens element 130, the object-side surface S7 of the fourth lens element 140 and the image-side surface S8 of the fourth lens element 140 are aspheric. It should be noted that the above surface may be an aspherical surface of the entire surface of the lens, or may be an aspherical surface of a portion of the surface of the lens, for example, a portion of the first lens 110 at a paraxial region is an aspherical surface.
Further, to save the cost of the optical system 100, the first lens 110, the second lens 120, the third lens 130 and the fourth lens 140 may be made of plastic materials. Considering that the imaging quality of the optical system 100 is closely related to not only the matching between the lenses in the optical system 100 but also the material of each lens, in order to improve the imaging quality of the optical system 100, in the embodiment of the present disclosure, the first lens 110 is made of a glass material, and all of the second lens 120, the third lens 130, and the fourth lens 140 are made of a plastic material. By designing the material of the first lens 110 as glass, the sensitivity of the optical system 100 to temperature can be effectively reduced by utilizing the characteristics of low thermal expansion coefficient and small change of refractive index with temperature of the glass material.
Further, in consideration of that the light beam emitted or reflected by the photographed object passes through the first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 of the optical system 100 in order from the object side to reach the imaging surface S11 and is imaged on the imaging surface S11, in order to ensure the imaging definition of the photographed object on the imaging surface S11, the optical system 100 may further include a filter 150, and the filter 150 may be disposed between the image side surface S8 of the fourth lens 140 and the imaging surface S11 of the optical system 100. The filter 150 includes a first surface S9 near the object side and a second surface S10 near the image side. Through the arrangement of the optical filter 150, the light beam passes through the optical filter 150 after passing through the fourth lens 140, and can effectively filter the light beam with a non-working wave band in the light beam, namely, can filter visible light and only allow infrared light to pass through, or can filter infrared light and only allow visible light to pass through, so that the imaging definition of a shot object on the imaging surface S11 is ensured.
Further, considering that the light beam emitted or reflected by the object passes through the first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 of the optical system 100 in order from the object side to reach the imaging surface S11 and is imaged on the imaging surface S11, in order to achieve protection of the imaging photosensitive element (e.g., the image sensor 210, hereinafter), the optical system 100 may further include a protective glass disposed between the image side surface S8 of the fourth lens 140 and the imaging surface S11. The protective glass comprises a third surface close to the object side and a fourth surface close to the image side. When the optical system 100 is also provided with the optical filter 150, the optical filter 150 is disposed on a side close to the image side surface S8 of the fourth lens 140, and the cover glass is correspondingly disposed between the second surface S10 of the optical filter 150 and the imaging surface S11.
From the above description of the embodiments, more particular embodiments and figures are presented below for purposes of illustration.
Example 1
Referring to fig. 1 to 5, the optical system 100 includes a stop STO, a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a filter 150, and an imaging surface S11 sequentially disposed along an optical axis of the optical system 100 from an object side to an image side.
The first lens element 110 with positive refractive power has a convex object-side surface S1 at a paraxial region and a convex image-side surface S2 at a paraxial region of the first lens element 110.
The second lens element 120 with positive refractive power has a concave object-side surface S3 at a paraxial region and a convex image-side surface S4 at a paraxial region of the second lens element 120.
The third lens element 130 with positive refractive power has a concave object-side surface S5 at a paraxial region and a convex image-side surface S6 at a paraxial region of the third lens element 130.
The fourth lens element 140 with negative refractive power has a convex object-side surface S7 at a paraxial region and a concave image-side surface S8 at a paraxial region of the fourth lens element 140.
By reasonably configuring the shape and positive and negative refractive power of each lens and setting the ratio of the effective focal length of each lens to the effective focal length of the optical system 100, the overall performance of the optical system 100 is optimized by controlling the curvature of the lens, the thickness of the lens, the spacing between the lenses, the aspherical coefficient of the lens, and the material of the lens, so that the optical system 100 has excellent imaging quality and temperature stability.
In the first embodiment, the reference wavelength of the focal length of each lens is 632.8nm. The relevant parameters of the optical system 100 are shown in table 1, where f in table 1 represents the effective focal length of the optical system 100, FNO represents the aperture value, and FOV represents the maximum field angle of the optical system 100, and it should be noted that the focal length, the radius of curvature, and the thickness are all in millimeters.
TABLE 1
In the first embodiment of the present disclosure, table 2 is obtained by substituting specific numerical values of the respective parameters of the optical system 100 into corresponding conditional expressions.
TABLE 2
The surfaces of the lenses of the optical system 100 may be aspherical, and for these aspherical surfaces, the aspherical equation for the aspherical surface is:
/>
wherein Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the vertex of the aspheric surface, k is a conic coefficient, ai is a coefficient corresponding to the i-th higher term in the aspheric surface type formula, and A4, A6, A8, A10, A12, A14 and A16 respectively represent aspheric coefficients of 4 th order, 6 th order, 8 th order, 10 th order, 12 th order, 14 th order and 16 th order. In the first embodiment of the present disclosure, the object-side surface S1 of the first lens element 110, the image-side surface S2 of the first lens element 110, the object-side surface S3 of the second lens element 120, the image-side surface S4 of the second lens element 120, the object-side surface S5 of the third lens element 130, the image-side surface S6 of the third lens element 130, the object-side surface S7 of the fourth lens element 140 and the image-side surface S8 of the fourth lens element 140 are aspheric, and the conical constants K and the aspheric coefficients corresponding to the aspheric surfaces corresponding to the respective lens elements are shown in table 3:
TABLE 3 Table 3
Fig. 2 is an MFT diagram of the optical system 100 at 1/4Ny, 1/2Ny, and Ny in the first embodiment of the present specification, wherein the abscissa along the X-axis direction represents half image height in mm and the ordinate along the Y-axis direction represents MTF value. As can be seen from fig. 2, the overall curve values are high, and the curve values smoothly decrease with increasing half-image height, indicating that the respective field MTFs of the optical system 100 in this embodiment one are good. (1/4 Ny= 43.0000p/mm,1/2 Ny= 83.0000p/mm, ny= 166.0000 p/mm)
Fig. 3 schematically shows a Through-Focus-MTF plot at a frequency of 43.0000p/mm for the optical system 100 in the first embodiment of the present specification, wherein the abscissa along the X-axis direction represents the defocus distance in mm and the ordinate along the Y-axis direction represents the MTF value. It can be seen from fig. 3 that the MTF peaks of each field of view are located substantially at the imaging plane S11 and are distributed substantially symmetrically about defocus, which indicates that the overall field curvature tolerance of the optical system 100 is relatively relaxed, which is advantageous for practical production assembly.
Fig. 4A is an astigmatic diagram of the optical system 100 according to the first embodiment of the present disclosure, in which the abscissa along the X-axis direction represents the focus offset amount, and the ordinate along the Y-axis direction represents the image height in mm. The S-curve in FIG. 4A represents a sagittal image surface curvature at a reference wavelength of 632.8nm, and the T-curve represents a meridional image surface curvature at a reference wavelength of 632.8 nm. At a reference wavelength of 632.8nm, it can be seen from fig. 4A that the image height is within 41.2mm, and the distortion is well compensated for by less than 0.5% overall.
Fig. 4B is a distortion graph of the optical system 100 according to the first embodiment of the present disclosure, wherein the distortion graph represents distortion magnitude values corresponding to different angles of view, and wherein the abscissa along the X-axis direction represents distortion and the ordinate along the Y-axis direction represents angle of view. In the case of the reference wavelength of 632.8nm, it can be seen from fig. 4B that the distortion is well corrected.
Fig. 5 is a graph showing the relative illuminance (ratio of the illuminance of each field to the illuminance of the central field) of the optical system 100 according to the first embodiment of the present disclosure, wherein the abscissa indicates the half image height and the ordinate indicates the ratio of the illuminance of the central field. As can be seen from fig. 5, the relative illuminance curve of the optical system 100 is overall smooth, no inflection, and the lowest relative illuminance is better than 29.5%, with higher relative illuminance.
In the first embodiment, the maximum variation of the focal length is 0.012mm, the maximum variation of the half field angle ω is 0.096 °, the maximum variation of the optical distortion is 0.099%, and the maximum variation of the imaging height of an object having a corresponding height of 35cm at 40cm is 7um on the imaging surface S11 in the process of changing the ambient temperature from-20 ℃ to 60 ℃.
Example two
Referring to fig. 6 to 10, the optical system 100 includes a stop STO, a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a filter 150, and an imaging surface S11 sequentially disposed along an optical axis of the optical system 100 from an object side to an image side.
The first lens element 110 with positive refractive power has a convex object-side surface S1 at a paraxial region and a convex image-side surface S2 at a paraxial region of the first lens element 110.
The second lens element 120 with positive refractive power has a concave object-side surface S3 at a paraxial region and a convex image-side surface S4 at a paraxial region of the second lens element 120.
The third lens element 130 with positive refractive power has a concave object-side surface S5 at a paraxial region and a convex image-side surface S6 at a paraxial region of the third lens element 130.
The fourth lens element 140 with negative refractive power has a convex object-side surface S7 at a paraxial region and a concave image-side surface S8 at a paraxial region of the fourth lens element 140.
By reasonably configuring the shape and positive and negative refractive power of each lens and setting the ratio of the effective focal length of each lens to the effective focal length of the optical system 100, the overall performance of the optical system 100 is optimized by controlling the curvature of the lens, the thickness of the lens, the spacing between the lenses, the aspherical coefficient of the lens, and the material of the lens, so that the optical system 100 has excellent imaging quality and temperature stability.
In the second embodiment, the reference wavelength of the focal length of each lens is 632.8nm. The relevant parameters of the optical system 100 are shown in table 4, where f in table 4 represents the effective focal length of the optical system 100, FNO represents the aperture value, and FOV represents the maximum field angle of the optical system 100, and it should be noted that the focal length, radius of curvature, and thickness are all in millimeters.
TABLE 4 Table 4
In the second embodiment of the present specification, table 5 is obtained by substituting specific numerical values of the respective parameters of the optical system 100 into corresponding conditional expressions.
TABLE 5
The surfaces of the lenses of the optical system 100 may be aspherical, and for these aspherical surfaces, the aspherical equation for the aspherical surface is:
wherein Z is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, r is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the vertex of the aspheric surface, k is a conic coefficient, ai is a coefficient corresponding to the i-th higher term in the aspheric surface type formula, and A4, A6, A8, A10, A12, A14 and A16 respectively represent aspheric coefficients of 4 th order, 6 th order, 8 th order, 10 th order, 12 th order, 14 th order and 16 th order. In the second embodiment of the present disclosure, the object-side surface S1 of the first lens element 110, the image-side surface S2 of the first lens element 110, the object-side surface S3 of the second lens element 120, the image-side surface S4 of the second lens element 120, the object-side surface S5 of the third lens element 130, the image-side surface S6 of the third lens element 130, the object-side surface S7 of the fourth lens element 140 and the image-side surface S8 of the fourth lens element 140 are aspheric, and the conical constants K and the aspheric coefficients corresponding to the aspheric surfaces corresponding to the respective lens elements are shown in table 6:
TABLE 6
| Face number | S1 | S2 | S3 | S4 |
| K | -4.61E+00 | -2.00E+02 | 2.31E+01 | 2.56E+00 |
| A4 | 1.62E-02 | -1.26E-01 | -1.97E-01 | -8.53E-02 |
| A6 | -3.10E-02 | -1.54E-01 | -2.80E-01 | -8.31E-03 |
| A8 | -5.81E-02 | -1.75E-01 | 6.97E-02 | 8.08E-02 |
| A10 | -2.73E-03 | 2.25E-01 | -3.16E-01 | -1.05E-01 |
| A12 | -9.11E-01 | 8.67E-02 | -1.19E+00 | 8.05E-02 |
| A14 | 3.32E+00 | -1.48E+00 | 5.02E-01 | 1.77E-01 |
| A16 | -3.90E+00 | 1.36E+00 | 1.90E+00 | -1.03E-01 |
| Face number | S5 | S6 | S7 | S8 |
| K | -1.53E+00 | -8.58E-01 | -2.84E+00 | -3.09E+00 |
| A4 | -1.00E-01 | 5.76E-02 | -7.46E-02 | -5.98E-02 |
| A6 | 2.45E-02 | -5.27E-02 | 6.44E-03 | 1.97E-02 |
| A8 | 1.88E-01 | 6.30E-02 | 1.03E-02 | -7.16E-03 |
| A10 | 8.03E-02 | -1.15E-02 | -1.05E-02 | 1.62E-03 |
| A12 | -6.51E-02 | 1.04E-02 | 4.31E-03 | -1.83E-04 |
| A14 | -7.82E-02 | -1.95E-02 | -8.48E-04 | 3.72E-06 |
| A16 | 4.01E-02 | 1.03E-02 | 6.69E-05 | 6.04E-07 |
Fig. 7 is an MFT diagram of the optical system 100 in the second embodiment of the present specification at 1/4Ny, 1/2Ny, and Ny, in which the abscissa along the X-axis direction represents half image height in mm and the ordinate along the Y-axis direction represents MTF value. As can be seen from fig. 7, the overall curve values are high, and the curve values smoothly decrease with increasing half image height, indicating that the respective field MTFs of the optical system 100 in the second embodiment are good. (1/4 Ny= 43.0000p/mm,1/2 Ny= 83.0000p/mm, ny= 166.0000 p/mm)
Fig. 8 schematically shows a Through-Focus-MTF plot at a frequency of 43.0000p/mm for the optical system 100 in the second embodiment of the present specification, wherein the abscissa along the X-axis direction represents the defocus distance in mm and the ordinate along the Y-axis direction represents the MTF value. It can be seen from fig. 8 that the MTF peaks of each field are located substantially at the imaging plane S11 and are distributed substantially symmetrically about defocus, which indicates that the overall field curvature tolerance of the optical system 100 is relatively relaxed, facilitating practical production assembly.
Fig. 9A is an astigmatic diagram of the optical system 100 in the second embodiment of the present specification, in which the abscissa in the X-axis direction represents the focus offset amount and the ordinate in the Y-axis direction represents the image height in mm. The S-curve in FIG. 9A represents a sagittal image surface curvature at a reference wavelength of 632.8nm, and the T-curve represents a meridional image surface curvature at a reference wavelength of 632.8 nm. In the case of the reference wavelength of 632.8nm, it can be seen from fig. 9A that the image height is within 41.2mm, and the distortion is well compensated for by less than 0.5% overall.
Fig. 9B is a distortion graph of the optical system 100 in the second embodiment of the present specification, the distortion graph representing distortion magnitude values corresponding to different angles of view, wherein the abscissa along the X-axis direction represents distortion, and the ordinate along the Y-axis direction represents angle of view. In the case of the reference wavelength of 632.8nm, it can be seen from fig. 9B that the distortion is well corrected.
Fig. 10 is a graph of the relative illuminance (ratio of the illuminance of each field to the illuminance of the central field) of the optical system 100 in the second embodiment of the present disclosure, wherein the abscissa indicates the half image height and the ordinate indicates the ratio of the illuminance of the central field. As can be seen from fig. 10, the relative illuminance curve of the optical system 100 is overall smooth, no inflection, and the lowest relative illuminance is better than 29.5% with higher relative illuminance.
In the second embodiment, the maximum variation of the focal length is 0.012mm, the maximum variation of the half field angle ω is 0.089 °, the maximum variation of the optical distortion is 0.12%, and the maximum variation of the imaging height of an object with a corresponding height of 35cm at 40cm is 7.3um on the imaging surface S11 in the process of changing the ambient temperature from-20 ℃ to 60 ℃.
The second aspect of the embodiments of the present disclosure provides an image capturing module 200, as shown in fig. 11, and fig. 11 is a schematic structural diagram of the image capturing module 200 in the embodiments of the present disclosure. The image capturing module 200 includes an image sensor 210 and the optical system 100, and the image sensor 210 is disposed on an image side of the optical system 100. The optical system 100 is configured to receive a light beam emitted by a subject and project the light beam onto the image sensor 210, where the image sensor 210 is configured to convert an optical signal of the light beam into an image signal. In the design, the image capturing module 200 with the optical system 100 meets the design of small volume and high pixels, and meanwhile, the image capturing module 200 has good temperature stability within the range of-20 ℃ to 60 ℃, so that the image capturing module 200 has good imaging quality.
A third aspect of the embodiments of the present disclosure provides an electronic device 300, as shown in fig. 12, and fig. 12 is a schematic structural diagram of the electronic device 300 in the embodiments of the present disclosure when it is a vehicle-mounted camera. The electronic device 300 includes a mounting structure 310 and the above-mentioned image capturing module 200, and the image capturing module 200 is disposed on the mounting structure 310. The mounting structure 310 is used for carrying an image capturing device, the mounting structure 310 may be directly a housing of the electronic device 300, or may be an intermediate connection structure for fixing the image capturing module 200 on the housing of the electronic device 300, where detailed description of a specific structure of the intermediate connection structure is omitted, and a designer may perform reasonable design according to actual needs. The electronic device 300 may be, but is not limited to, a device with camera function such as a cell phone, a video camera, a computer, etc. As shown in fig. 12, the electronic apparatus 300 is an in-vehicle camera. In the design, the electronic equipment 300 with the image capturing module 200 meets the design of small volume and high pixels, and meanwhile, the electronic equipment 300 has good temperature stability within the range of-20 ℃ to 60 ℃, so that the electronic equipment 300 has good imaging quality.
A fourth aspect of the present embodiment provides a carrier 400, as shown in fig. 13, and fig. 13 is a schematic structural diagram of the carrier 400 in the present embodiment when the vehicle is a vehicle. The carrier 400 includes a connection structure and the electronic device 300, and the electronic device 300 is disposed on the connection structure (not shown). The connection structure is used for carrying the electronic device 300, and the connection structure may be directly a housing of the carrier 400, or may be an intermediate connection structure for fixing the electronic device 300 on the housing of the carrier 400, which is not described herein in detail, and a designer may perform reasonable design according to actual needs. The vehicle 400 may be, but is not limited to, a vehicle, an aircraft, or other traffic device having a camera function. As shown in fig. 13, the carrier 400 is an automobile. In the design, the carrier 400 with the image capturing module 200 meets the design of small volume and high pixels, and meanwhile, the carrier 400 has good temperature stability within the range of-20 ℃ to 60 ℃, so that the carrier 400 has good imaging quality.
The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the embodiments of the present specification, it should be understood that, if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", etc., based on the orientation or positional relationship shown in the drawings, it is merely for convenience of describing the embodiments of the present specification and simplifying the description, rather than indicating or suggesting that the apparatus or element being referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus the terms describing the positional relationship in the drawings are merely for exemplary illustration and should not be construed as limiting the present patent, and the specific meaning of the terms may be understood by those of ordinary skill in the art according to the specific circumstances.
Claims (12)
1. An optical system comprising four lenses in order from an object side to an image side along an optical axis of the optical system:
a first lens element with positive refractive power having a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
a second lens element with positive refractive power having a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
A third lens element with positive refractive power having a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
a fourth lens element with negative refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region;
the effective focal length of the optical system is f, the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis is TTL, and f and TTL satisfy the conditional expression:
0.5＜f/TTL＜0.7；
the thickness of the first lens at the optical axis is n1, and n1 satisfies the following conditional expression:
-0.00001＜dn1/dt＜0.0。
2. the optical system according to claim 1,
the focal length of the first lens is f1, wherein f1 and f satisfy the following conditional expression:
1.0＜f1/f＜2.0。
3. the optical system according to claim 1,
the focal length of the second lens is f2, wherein f2 and f satisfy the following conditional expression:
1.5＜f2/f＜2.6。
4. the optical system according to claim 1,
the focal length of the third lens is f3, wherein f3 and f satisfy the following conditional expression:
1.6＜f3/f＜2.8。
5. the optical system according to claim 1,
the focal length of the fourth lens is f4, wherein f4 and f satisfy the following conditional expression:
-5.0＜f4/f＜-2.0。
6. the optical system according to claim 1,
The curvature radius of the object side surface of the first lens element at the paraxial region is R11, and the curvature radius of the image side surface of the first lens element at the paraxial region is R12, wherein R11 and R12 satisfy the following conditional expression:
-1.5＜（R11-R12）/（R11+R12）＜-0.5。
7. the optical system according to claim 1,
the curvature radius of the object side surface of the second lens element at the paraxial region is R21, and the curvature radius of the image side surface of the second lens element at the paraxial region is R22, wherein R21 and R22 satisfy the following conditional expression:
0.2＜（R21-R22）/（R21+R22）＜0.6。
8. the optical system according to claim 1,
the radius of curvature of the object-side surface of the third lens element at the paraxial region is R31, and the radius of curvature of the image-side surface of the third lens element at the paraxial region is R32, wherein R31 and R32 satisfy the following conditional expression:
-0.1＜（R31-R32）/（R31+R32）＜-0.01。
9. the optical system according to claim 1,
the radius of curvature of the object-side surface of the fourth lens element at the paraxial region is R41, and the radius of curvature of the image-side surface of the fourth lens element at the paraxial region is R42, wherein R41 and R42 satisfy the following conditional expression:
0.1＜（R41-R42）/（R41+R42）＜0.2。
10. an image capturing module, comprising:
the optical system of any one of claims 1-9; and
An image sensor disposed on an image side of the optical system.
11. An electronic device, comprising:
A mounting structure; and
The image capturing module of claim 10, the image capturing module being disposed on the mounting structure.
12. A carrier, comprising:
a connection structure; and
The electronic device of claim 11, disposed on the connection structure.
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| CN101276041A (en) * | 2007-03-28 | 2008-10-01 | 柯尼卡美能达精密光学株式会社 | Image pickup lens, image pickup apparatus and mobile terminal |
| CN104280861A (en) * | 2013-07-05 | 2015-01-14 | 大立光电股份有限公司 | Image capturing lens assembly and image capturing device |
| US9784945B1 (en) * | 2016-04-06 | 2017-10-10 | Largan Precision Co., Ltd. | Optical lens assembly, image capturing apparatus and electronic device |
| CN107632367A (en) * | 2016-07-18 | 2018-01-26 | 先进光电科技股份有限公司 | Optical imaging system |
| CN110632737A (en) * | 2018-06-25 | 2019-12-31 | 新巨科技股份有限公司 | Four-piece infrared single-wavelength lens group |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2021195891A1 (en) * | 2020-03-30 | 2021-10-07 | 江西晶超光学有限公司 | Optical imaging system, image capturing apparatus and electronic device |
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| CN101276041A (en) * | 2007-03-28 | 2008-10-01 | 柯尼卡美能达精密光学株式会社 | Image pickup lens, image pickup apparatus and mobile terminal |
| CN104280861A (en) * | 2013-07-05 | 2015-01-14 | 大立光电股份有限公司 | Image capturing lens assembly and image capturing device |
| US9784945B1 (en) * | 2016-04-06 | 2017-10-10 | Largan Precision Co., Ltd. | Optical lens assembly, image capturing apparatus and electronic device |
| CN107632367A (en) * | 2016-07-18 | 2018-01-26 | 先进光电科技股份有限公司 | Optical imaging system |
| CN110632737A (en) * | 2018-06-25 | 2019-12-31 | 新巨科技股份有限公司 | Four-piece infrared single-wavelength lens group |
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