CN113885174A - Optical system, lens module and electronic equipment - Google Patents
Optical system, lens module and electronic equipment Download PDFInfo
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- CN113885174A CN113885174A CN202111238493.9A CN202111238493A CN113885174A CN 113885174 A CN113885174 A CN 113885174A CN 202111238493 A CN202111238493 A CN 202111238493A CN 113885174 A CN113885174 A CN 113885174A
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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
- G02B13/0045—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 five or more lenses
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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
- G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
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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
- G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
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Abstract
An optical system, a lens module and an electronic device, the optical system sequentially comprises from an object side to an image side along an optical axis: the first lens element, the second lens element and the fourth lens element have negative refractive power, and the third lens element and the fifth lens element have positive refractive power. The object-side surfaces of the second lens element and the fifth lens element are convex at a paraxial region, the image-side surfaces of the second lens element and the fourth lens element are concave at a paraxial region, and the image-side surfaces of the third lens element and the fifth lens element are convex at a paraxial region. The optical system satisfies the relation: 8mm2<f1*f2<11.5mm2F1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. By reasonably designing the surface shapes and the refractive powers of the first lens element to the fifth lens element and enabling the optical system to satisfy the relation formula, the optical system is favorable for having high imaging componentThe field angle range is expanded while the resolution is increased.
Description
Technical Field
The invention belongs to the technical field of optical imaging, and particularly relates to an optical system, a lens module and electronic equipment.
Background
With the development of society, the requirements of various fields on safety and monitoring are higher and higher, especially in the traffic field and the vehicle-mounted monitoring field. The current mainstream lenses in the market have the problem of small visual angle, for example, the condition of the edge of a vehicle is difficult to record in the driving process of the vehicle, the resolution of the similar lenses is low, and the integral definition of a shot image is low. That is, the conventional lens cannot satisfy both of a large field angle and high definition.
Disclosure of Invention
An object of the present invention is to provide an optical system, a lens module, and an electronic apparatus capable of expanding a field angle range while having a high imaging resolution.
In order to realize the purpose of the invention, the invention provides the following technical scheme:
in a first aspect, the present invention provides an optical system, in order from an object side to an image side along an optical axis direction, comprising: a first lens element with negative refractive power; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; the third lens element with positive refractive power has a convex object-side surface and a convex image-side surface at a paraxial region; a fourth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a fifth lens element with positive refractive power having convex object-side and image-side surfaces at paraxial region; the optical system satisfies the relation: 8mm2<f1*f2<11.5mm2(ii) a Wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.
The first lens provides negative refractive power for the optical system, and the lens close to the object side is set as a negative lens, so that light rays emitted into the optical system at a large angle can be captured, and the field angle range of the optical system is expanded; the second lens provides negative refractive power for the optical system, which is beneficial to widening the width of light beams and enabling light rays with large angles to be wider after being refracted by the first lens, and the object side surface of the second lens is a convex surface and can further converge the light rays, so that the surface shape is smooth, and the deviation of the incident angles and the emergent angles of the light rays with different view fields can be reduced; the image side surface of the second lens is a concave surface, so that the trend of a light path is favorably controlled, and the outer diameter of the lens is prevented from being too large; the third lens provides positive refractive power for the optical system, and the object side surface and the image side surface of the third lens are both convex surfaces, so that light rays can be converged, the edge aberration can be corrected, and the imaging resolution can be improved; the fourth lens provides negative refractive power for the optical system, the fifth lens provides positive refractive power for the optical system, the astigmatism generated by the refraction and rotation of the front lens group of the aberration and correction light is favorably eliminated through the structure that the fourth lens and the fifth lens are glued, the image side surface of the fifth lens is a convex surface, the phase difference is favorably balanced, and the total length of the optical system is favorably controlled. Satisfying the above relation is advantageous for increasing the field angle range of the optical system while providing the optical system with high imaging resolution. If the refractive power of the first lens element and the second lens element is insufficient, large-angle light is difficult to enter the optical system, and the field angle range of the optical system is not enlarged; when the refractive power of the first lens element and the second lens element is lower than the lower limit of the relational expression, the first lens element and the second lens element have too strong refractive power, and are prone to generate strong astigmatism and chromatic aberration, which are not favorable for high-resolution imaging characteristics.
In one embodiment, at least one lens of the optical system is a plastic aspheric lens, and the at least one lens satisfies the following relation: vd < 28; and Vd is the Abbe number of the optical system. The above relational expression is satisfied, which is beneficial to better correcting chromatic aberration and improving imaging quality.
In one embodiment, at least one lens in the optical system satisfies the following relation: 3.5< f3/f < 8; wherein f3 is an effective focal length of the third lens, and f is an effective focal length of the optical system. The light rays are emitted from the first lens element and the second lens element with negative refractive power, and the marginal light rays are incident on the image surface and are easy to generate larger field curvature, so that the third lens element with positive refractive power reasonably distributes the refractive power of the third lens element, thereby being beneficial to correcting marginal aberration and improving imaging resolution; if the refractive power of the third lens element is lower than the lower limit of the relational expression, the refractive power of the third lens element is too high, and the refractive power of the third lens element is too low or too high to facilitate the correction of the aberration of the optical system, thereby reducing the imaging quality.
In one embodiment, the optical system satisfies the relationship: 1< (Rs5-Rs6)/(Rs5+ Rs6) < 4; wherein Rs5 is a radius of curvature of the object-side surface of the third lens element at the optical axis, and Rs6 is a radius of curvature of the image-side surface of the third lens element at the optical axis. Satisfying the above formula, the difference between the two surface types is small, which is beneficial to eliminating aberration and astigmatism, and reducing the chief ray incident angle of the marginal field. If the angle exceeds the upper limit of the relational expression, the image side surface of the third lens is too gentle, marginal rays are difficult to control, and the effect of correcting the incident angle of the chief rays of the marginal field of view cannot be achieved.
In one embodiment, the optical system satisfies the relationship: 3< f45/(CT5-CT4) < 4; wherein f45 is a combined focal length of the fourth lens element and the fifth lens element, CT4 is an optical thickness of the fourth lens element, and CT5 is an optical thickness of the fifth lens element. By reasonably matching the thickness relationship between the fourth lens element and the fifth lens element, the refractive powers of the two lens elements with negative and positive refractive powers can be reasonably matched, so that the aberration can be corrected with each other, and the fourth lens element and the fifth lens element can provide the minimum aberration contribution ratio for the optical system. Below the lower limit of the relational expression, the thickness difference between the centers of the fourth lens and the fifth lens is too large, which is not beneficial to the gluing process, and meanwhile, under the environment with large variation of high and low temperature environments, the cold and hot deformation difference generated by the thickness difference is large, so that the phenomena of glue cracking or glue failure and the like are easy to generate; if the combined focal length of the fourth lens element and the fifth lens element is too large, the lens assembly is prone to generate a severe astigmatism, which is not favorable for improving the imaging quality.
In one embodiment, the optical system satisfies the relationship: 13.5< TTL/f < 18; wherein, TTL is the total length of the optical system, and f is the effective focal length of the optical system. By defining the relationship between the total length of the optical system and the focal length of the optical system, the optical total length of the optical system is controlled while the field angle range of the optical system is satisfied, and the characteristic of miniaturization of the optical system is satisfied. Exceeding the upper limit of the relational expression, the total length of the optical system is too long, which is not beneficial to miniaturization; if the focal length of the optical system is too long below the lower limit of the relational expression, it is not favorable to satisfy the field angle range of the optical system, and sufficient object space information cannot be obtained.
In one embodiment, the optical system satisfies the relationship: 3< (CT3+ d34)/f < 4.5; wherein CT3 is the thickness of the third lens on the optical axis, d34 is the air space between the third lens and the fourth lens on the optical axis, and f is the effective focal length of the optical system. The upper limit of the relational expression is met, the thickness of the third lens and the air space between the third lens and the fourth lens on the optical axis can be prevented from being too large, and therefore the miniaturization of an optical system is facilitated; and on the premise of meeting the optical performance of the optical system, the central thickness of the third lens and the distance between the third lens and the fourth lens on the air space on the optical axis are increased, so that the aberration of the optical system can be corrected, and the imaging quality of the optical system can be improved.
In one embodiment, the optical system satisfies the relationship: 7< Rs3/CT2< 10.5; wherein Rs3 is the radius of curvature of the object-side surface of the second lens at the optical axis, and CT2 is the thickness of the second lens at the optical axis. The object side surface of the second lens is a convex surface, so that light can be further converged, the surface shape is smooth, and the deviation of incident angles and emergent angles of light with different viewing fields can be reduced, so that the sensitivity is reduced; through to the reasonable setting of second lens thickness can reduce the processing degree of difficulty, and reduces thickness tolerance sensitivity, promotes the yield.
In one embodiment, the optical system satisfies the relationship: 40 ° < (FOV. f)/2. Imgh <55 °; wherein FOV is the maximum field angle of the optical system, f is the effective focal length of the optical system, and Imgh is the image height corresponding to half of the maximum field angle of the optical system. By satisfying the relational expression, the optical performance of the optical system can be kept good, the high-pixel characteristic of the optical system can be realized, and the details of the object to be shot can be captured well.
In a second aspect, the present invention further provides a lens module, which includes a lens barrel, a photosensitive element and the optical system according to any one of the embodiments of the first aspect, wherein the first to fifth lenses of the optical system are mounted in the lens barrel, and the photosensitive element is disposed on an image side of the optical system. By adding the optical system provided by the invention into the lens module, the lens module has high imaging resolution and simultaneously expands the field angle range.
In a third aspect, the present invention further provides an electronic device, which includes a housing and the lens module set in the second aspect, wherein the lens module set is disposed in the housing. By adding the lens module provided by the invention into the electronic equipment, the electronic equipment can maintain good shooting performance, has high imaging resolution and expands the field angle range.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic configuration diagram of an optical system of a first embodiment;
FIG. 2 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the first embodiment;
FIG. 3 is a schematic structural view of an optical system of a second embodiment;
FIG. 4 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the second embodiment;
fig. 5 is a schematic structural view of an optical system of a third embodiment;
FIG. 6 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the third embodiment;
fig. 7 is a schematic configuration diagram of an optical system of a fourth embodiment;
FIG. 8 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the fourth embodiment;
fig. 9 is a schematic configuration diagram of an optical system of the fifth embodiment;
fig. 10 is a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the fifth embodiment.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The invention provides an optical system, comprising in order from an object side to an image side along an optical axis: a first lens element with negative refractive power; the second lens element with negative refractive power has a convex object-side surface at paraxial region and a concave image-side surface at paraxial region; the third lens element with positive refractive power has a convex object-side surface and a convex image-side surface at paraxial region; a fourth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; the fifth lens element with positive refractive power has a convex object-side surface and a convex image-side surface at paraxial region; the optical system satisfies the relation: 8mm2<f1*f2<11.5mm2(ii) a Wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.
The first lens provides negative refractive power for the optical system, and the lens close to the object side is set as a negative lens, so that light rays emitted into the optical system at a large angle can be captured, and the field angle range of the optical system is enlarged; the second lens provides negative refractive power for the optical system, which is beneficial to widening the width of the light beam and enabling the light rays with large angles to be wider after being refracted by the first lens, and the object side surface of the second lens is a convex surface, so that the light rays can be further converged, the surface shape is smooth, and the deviation of the incident angle and the emergent angle of the light rays with different viewing fields can be reduced; the image side surface of the second lens is a concave surface, which is beneficial to controlling the trend of a light path and avoiding the overlarge outer diameter of the lens; the third lens provides positive refractive power for the optical system, and the object side surface and the image side surface of the third lens are both convex surfaces, so that light rays can be converged, the edge aberration can be corrected, and the imaging resolution can be improved; the fourth lens provides negative refractive power for the optical system, the fifth lens provides positive refractive power for the optical system, astigmatism generated by the refraction and rotation of the front lens group of aberration and corrected light is favorably eliminated through a structure that the fourth lens and the fifth lens are glued, the image side surface of the fifth lens is a convex surface, phase difference is favorably balanced, and the total length of the optical system is favorably controlled. Satisfying the above relation is advantageous for increasing the field angle range of the optical system while providing the optical system with high imaging resolution. If the refractive power of the first lens element and the second lens element is insufficient, the large-angle light is difficult to enter the optical system, which is not favorable for expanding the field angle range of the optical system; when the refractive power of the first lens element and the second lens element is lower than the lower limit of the relational expression, the first lens element and the second lens element have too strong refractive power, which tends to generate strong astigmatism and chromatic aberration, which is not favorable for high-resolution imaging characteristics.
In one embodiment, at least one lens of the optical system is a plastic aspheric lens, and the at least one lens satisfies the following relation: vd < 28; wherein Vd is the abbe number of the optical system. The above relational expression is satisfied, which is beneficial to better correcting chromatic aberration and improving imaging quality.
In one embodiment, at least one lens in the optical system satisfies the following relationship: 3.5< f3/f < 8; where f3 is the effective focal length of the third lens, and f is the effective focal length of the optical system. The light rays are emitted from the first lens and the second lens with negative refractive power, and the marginal light rays are incident on the image surface and are easy to generate larger field curvature, so that the third lens has positive refractive power, and the refractive power of the third lens is reasonably distributed, thereby being beneficial to correcting marginal aberration and improving imaging resolution; if the refractive power of the third lens element is lower than the lower limit of the relational expression, the refractive power of the third lens element is too high, and the refractive power of the third lens element is too low or too high to facilitate the correction of the aberration of the optical system, thereby reducing the imaging quality.
In one embodiment, the optical system satisfies the relationship: 1< (Rs5-Rs6)/(Rs5+ Rs6) < 4; wherein Rs5 is a curvature radius of the object-side surface of the third lens element at the optical axis, and Rs6 is a curvature radius of the image-side surface of the third lens element at the optical axis. Satisfying the above formula, the difference between the two surface types is small, which is beneficial to eliminating aberration and astigmatism, and reducing the chief ray incident angle of the marginal field. If the angle exceeds the upper limit of the relational expression, the image side surface of the third lens is too gentle, marginal rays are difficult to control, and the effect of correcting the incident angle of the chief rays of the marginal field of view cannot be achieved.
In one embodiment, the optical system satisfies the relationship: 3< f45/(CT5-CT4) < 4; wherein f45 is a combined focal length of the fourth lens element and the fifth lens element, CT4 is an optical thickness of the fourth lens element, and CT5 is an optical thickness of the fifth lens element. By reasonably matching the thickness relationship between the fourth lens element and the fifth lens element, the refractive powers of the two lens elements with negative and positive refractive powers can be reasonably matched, so that the aberration can be corrected with each other, and the fourth lens element and the fifth lens element can provide the minimum aberration contribution ratio for the optical system. Below the lower limit of the relational expression, the difference between the central thicknesses of the fourth lens and the fifth lens is too large, which is not beneficial to the gluing process, and meanwhile, under the environment with large variation of high and low temperature environments, the difference of cold and hot deformation caused by the difference of the thicknesses is large, so that the phenomena of glue cracking or glue removing and the like are easy to generate; if the combined focal length of the fourth lens element and the fifth lens element is too large, the lens assembly is prone to generate a severe astigmatism, which is not favorable for improving the imaging quality.
In one embodiment, the optical system satisfies the relationship: 13.5< TTL/f < 18; wherein, TTL is the total length of the optical system, and f is the effective focal length of the optical system. By limiting the relationship between the total length of the optical system and the focal length of the optical system, the optical total length of the optical system is controlled while the field angle range of the optical system is satisfied, and the characteristic of miniaturization of the optical system is satisfied. The total length of the optical system is too long to be beneficial to miniaturization when exceeding the upper limit of the relational expression; if the focal length of the optical system is too long below the lower limit of the relational expression, it is not favorable to satisfy the field angle range of the optical system, and sufficient object space information cannot be obtained.
In one embodiment, the optical system satisfies the relationship: 3< (CT3+ d34)/f < 4.5; wherein CT3 is the thickness of the third lens on the optical axis, d34 is the air space between the third lens and the fourth lens on the optical axis, and f is the effective focal length of the optical system. The upper limit of the relational expression is met, the thickness of the third lens and the overlarge air interval between the third lens and the fourth lens on the optical axis can be avoided, and therefore the miniaturization of an optical system is facilitated; the lower limit of the relational expression is met, and on the premise of meeting the optical performance of the optical system, the central thickness of the third lens and the air interval distance between the third lens and the fourth lens on the optical axis are increased, so that the aberration of the optical system can be corrected favorably, and the imaging quality of the optical system can be improved.
In one embodiment, the optical system satisfies the relationship: 7< Rs3/CT2< 10.5; wherein Rs3 is the curvature radius of the object-side surface of the second lens element at the optical axis, and CT2 is the thickness of the second lens element at the optical axis. The object side surface of the second lens is a convex surface, so that light can be further converged, the surface shape is smooth, and the deviation of incident angles and emergent angles of light with different viewing fields can be reduced, so that the sensitivity is reduced; through the reasonable setting to second lens thickness, can reduce the processing degree of difficulty, and reduce thickness tolerance sensitivity, promote the yield.
In one embodiment, the optical system satisfies the relationship: 40 ° < (FOV. f)/2. Imgh <55 °; where FOV is the maximum angle of view of the optical system, f is the effective focal length of the optical system, and Imgh is the image height corresponding to half of the maximum angle of view of the optical system. By satisfying the relational expression, the optical performance of the optical system can be maintained, the high-pixel characteristic of the optical system can be realized, and the details of the object to be photographed can be captured well.
The invention also provides a lens module, which comprises a lens barrel, a photosensitive element and the optical system provided by the embodiment of the invention, wherein the first lens to the fifth lens of the optical system are arranged in the lens barrel, and the photosensitive element is arranged at the image side of the optical system. Furthermore, the photosensitive element is an electronic photosensitive element, a photosensitive surface of the electronic photosensitive element is positioned on an imaging surface of the optical system, and light rays of an object which pass through the lens and enter the photosensitive surface of the electronic photosensitive element can be converted into electric signals of an image. The electron sensor may be a Complementary Metal Oxide Semiconductor (CMOS) or a Charge-coupled Device (CCD). By adding the optical system provided by the invention into the lens module, the lens module can keep good shooting performance, has high imaging resolution and expands the field angle range.
The embodiment of the invention provides electronic equipment, which comprises a shell and a lens module provided by the embodiment of the invention, wherein the lens module is arranged in the shell. The electronic equipment can be an automobile driving auxiliary camera such as an automatic cruise camera, a vehicle traveling recorder, a reverse image and the like, and can also be an imaging module integrated on a digital camera and various video devices. By adding the lens module provided by the invention into the electronic equipment, the electronic equipment can maintain good shooting performance, has high imaging resolution and expands the field angle range.
First embodiment
Referring to fig. 1 and fig. 2, the optical system of the present embodiment, in order from an object side to an image side along an optical axis, includes:
the first lens element L1 with negative refractive power has a convex object-side surface S1 at a paraxial region and a concave image-side surface S2 at a paraxial region of the first lens element L1.
The second lens element L2 with negative refractive power has a convex object-side surface S3 at a paraxial region and a concave image-side surface S4 at a paraxial region of the second lens element L2.
The third lens element L3 with positive refractive power has a convex object-side surface S5 and an convex image-side surface S6 at paraxial region of the third lens element L3.
The fourth lens element L4 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 L4.
The fifth lens element L5 with positive refractive power has a convex object-side surface S9 and an convex image-side surface S10 at paraxial region of the fifth lens element L5.
The first lens L1 to the fifth lens L5 may be made of plastic, glass, or a glass-plastic composite material.
In addition, the optical system further includes a stop STO, which is disposed between the third lens L3 and the fourth lens L4 in this embodiment, and in other embodiments, the stop STO may be disposed between any two lenses or on any lens surface. The optical system further includes an infrared cut filter IR and an imaging plane IMG. The infrared cut filter IR is disposed between the image side surface S10 and the image side surface IMG of the fifth lens L5, and includes an object side surface S15 and an image side surface S16, and is configured to filter infrared light, so that the light incident on the image side surface IMG is visible light, and the wavelength of the visible light is 380nm to 780 nm. The material of the IR filter is glass, and a film may be coated on the glass, such as cover glass with a filtering function, or cob (chips on board) formed by directly encapsulating a bare chip with a filter. The effective pixel area of the electronic photosensitive element is positioned on the imaging surface IMG.
Table 1a shows a table of characteristics of the optical system of the present embodiment, in which the reference wavelength of the focal length is 542.02nm, the refractive index and abbe number of the material are each obtained by visible light having a reference wavelength of 587.6nm, and the units of the Y radius, thickness, and focal length are all millimeters (mm), where positive and negative values of the thickness value represent directions only.
TABLE 1a
Wherein f is the effective focal length of the optical system, FNO is the f-number of the optical system, and FOV is the maximum field angle of the optical system.
In this embodiment, the aspheric surface profile x can be defined using, but not limited to, the following aspheric surface formula:
where x is the distance from the corresponding point on the aspheric surface to a plane tangent to the surface vertex and h is the distance on the aspheric surface
The distance from the corresponding point to the optical axis, c is the curvature of the aspheric vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric 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 aspherical mirror surface in the first embodiment.
TABLE 1b
| Number of noodles | S3 | S4 | S8 | S9 | S10 |
| K | -4.3276E+01 | -1.4328E+00 | -2.9738E+01 | -2.9738E+01 | -1.2297E+00 |
| A4 | -2.7480E-03 | -3.4633E-01 | 3.2316E-01 | 3.2316E-01 | 2.3136E-01 |
| A6 | 9.0598E-02 | 4.9292E+00 | -2.1567E+00 | -2.1567E+00 | -2.6574E+00 |
| A8 | -1.9311E-01 | -2.3068E+01 | 1.5116E+01 | 1.5116E+01 | 2.0822E+01 |
| A10 | 3.7232E-01 | 7.3155E+00 | -8.8123E+00 | -8.0812E+01 | -9.7160E+01 |
| A12 | -1.8354E-01 | -1.4276E+02 | 2.5216E+02 | 2.5216E+02 | 2.8520E+02 |
| A14 | 8.6741E-02 | 1.7447E+02 | -3.1276E+02 | -3.1276E+02 | -5.2932E+02 |
| A16 | -2.4768E-02 | -1.2895E+02 | -3.5311E+02 | -3.5311E+02 | 6.0248E+02 |
| A18 | 3.9007E-03 | 5.2598E+01 | 1.3789E+03 | 1.3789E+03 | -3.8244E+02 |
| A20 | -2.5958E-04 | -9.0670E+00 | -1.0466E+03 | -1.0466E+03 | 1.0336E+02 |
Fig. 2 (a) shows a longitudinal spherical aberration curve of the optical system of the first embodiment at wavelengths of 642.7300nm, 590.8600nm, 542.0200nm, 500.4800nm and 465.6100nm, wherein the abscissa in the X-axis direction represents the focus shift, the ordinate in the Y-axis direction represents the normalized field of view, and the longitudinal spherical aberration curve represents the convergent focus deviation of light rays of different wavelengths after passing through the respective lenses of the optical system. As can be seen from fig. 2 (a), the spherical aberration value of the optical system in the first embodiment is better, which illustrates that the imaging quality of the optical system in this embodiment is better.
Fig. 2 (b) also shows an astigmatism graph of the optical system of the first embodiment at a wavelength of 542.0200nm, in which the abscissa in the X-axis direction represents the focus shift and the ordinate in the Y-axis direction represents the image height in mm. The astigmatism curves represent the meridional imaging plane curvature T and the sagittal imaging plane curvature S. As can be seen from (b) of fig. 2, astigmatism of the optical system is well compensated.
Fig. 2 (c) also shows a distortion curve of the optical system of the first embodiment at a wavelength of 542.0200 nm. The abscissa along the X-axis direction represents the focus offset, the ordinate along the Y-axis direction represents the image height, and the distortion curve represents the distortion magnitude values corresponding to different angles of view. As can be seen from (c) in fig. 2, the distortion of the optical system is well corrected at a wavelength of 542.0200 nm.
As can be seen from (a), (b), and (c) in fig. 2, the optical system of the present embodiment has small aberration, good imaging quality, and good imaging quality.
Second embodiment
Referring to fig. 3 and 4, the optical system of the present embodiment, in order from an object side to an image side along an optical axis, includes:
the first lens element L1 with negative refractive power has a convex object-side surface S1 at a paraxial region and a concave image-side surface S2 at a paraxial region of the first lens element L1.
The second lens element L2 with negative refractive power has a convex object-side surface S3 at a paraxial region and a concave image-side surface S4 at a paraxial region of the second lens element L2.
The third lens element L3 with positive refractive power has a convex object-side surface S5 and an convex image-side surface S6 at paraxial region of the third lens element L3.
The fourth lens element L4 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 L4.
The fifth lens element L5 with positive refractive power has a convex object-side surface S9 and an convex image-side surface S10 at paraxial region of the fifth lens element L5.
Other structures of the second embodiment are the same as those of the first embodiment, and reference may be made thereto.
Table 2a shows a table of characteristics of the optical system of the present embodiment, in which the reference wavelength of the focal length is 542.02nm, the refractive index and abbe number of the material are obtained by visible light having a reference wavelength of 587.6nm, the units of the Y radius, the thickness and the focal length are millimeters (mm), wherein the positive and negative values of the thickness value represent directions only, and the other parameters have the same meanings as those of the first embodiment.
TABLE 2a
In the present embodiment, table 2b gives the coefficients of high-order terms that can be used for each aspherical mirror in the second embodiment, wherein each aspherical mirror type can be defined by the formula given in the first embodiment.
TABLE 2b
| Number of noodles | S3 | S4 | S8 | S9 | S10 |
| K | -2.5268E+01 | -1.1869E+00 | -2.8786E+01 | -2.1165E+00 | -1.2477E+00 |
| A4 | -4.4116E-02 | -3.9083E-01 | 3.2655E-01 | 2.3135E+00 | 2.3374E-01 |
| A6 | 8.5961E-02 | 4.2820E+00 | -2.1512E+00 | -3.1264E+01 | -2.6470E+00 |
| A8 | -1.1238E-01 | -2.0687E+00 | 1.1075E+00 | 2.9849E+02 | 2.0824E+01 |
| A10 | 2.4136E-01 | 7.2875E+01 | -8.0722E+01 | -1.7379E+03 | -9.7185E+01 |
| A12 | -1.8354E-01 | -1.4276E+02 | 2.5216E+02 | 6.1264E+03 | 2.8520E+02 |
| A14 | 8.6743E-02 | 1.4717E+00 | -3.1276E+02 | -1.3249E+04 | -5.2932E+02 |
| A16 | -2.4767E-02 | -1.2895E+02 | -3.5311E+02 | 1.7180E+04 | 6.0248E+02 |
| A18 | 3.9006E-03 | 5.2598E+01 | 1.3789E+03 | -1.2262E+04 | -3.8244E+02 |
| A20 | -2.5964E-04 | -9.0670E+00 | -1.0466E+03 | 3.7022E+03 | 1.0336E+02 |
FIG. 4 shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the second embodiment, wherein the longitudinal spherical aberration curve represents the convergent focus deviations of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curves represent meridional imaging plane curvature and sagittal imaging plane curvature; the distortion curve represents the distortion magnitude values corresponding to different angles of view. As can be seen from the aberration diagram in fig. 4, the longitudinal spherical aberration, curvature of field, and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality.
Third embodiment
Referring to fig. 5 and fig. 6, the optical system of the present embodiment, in order from an object side to an image side along an optical axis, includes:
the first lens element L1 with negative refractive power has a convex object-side surface S1 at a paraxial region and a concave image-side surface S2 at a paraxial region of the first lens element L1.
The second lens element L2 with negative refractive power has a convex object-side surface S3 at a paraxial region and a concave image-side surface S4 at a paraxial region of the second lens element L2.
The third lens element L3 with positive refractive power has a convex object-side surface S5 and an convex image-side surface S6 at paraxial region of the third lens element L3.
The fourth lens element L4 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 L4.
The fifth lens element L5 with positive refractive power has a convex object-side surface S9 and an convex image-side surface S10 at paraxial region of the fifth lens element L5.
Other structures of the third embodiment are the same as those of the first embodiment, and reference may be made thereto.
Table 3a shows a table of characteristics of the optical system of the present embodiment, in which the reference wavelength of the focal length is 542.02nm, the refractive index and abbe number of the material are obtained by visible light having a reference wavelength of 587.6nm, the units of the Y radius, the thickness and the focal length are millimeters (mm), wherein the positive and negative values of the thickness value represent directions only, and the other parameters have the same meanings as those of the first embodiment.
TABLE 3a
Table 3b gives the coefficients of high-order terms that can be used for each aspherical mirror surface in the third embodiment, wherein each aspherical mirror surface type can be defined by the formula given in the first embodiment.
TABLE 3b
FIG. 6 shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the third embodiment, wherein the longitudinal spherical aberration curves represent the convergent focus deviations of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curves represent meridional imaging plane curvature and sagittal imaging plane curvature; the distortion curve represents the distortion magnitude values corresponding to different angles of view. As can be seen from the aberration diagram in fig. 6, the longitudinal spherical aberration, curvature of field, and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality.
Fourth embodiment
Referring to fig. 7 and 8, the optical system of the present embodiment, in order from an object side to an image side along an optical axis, includes:
the first lens element L1 with negative refractive power has a convex object-side surface S1 at a paraxial region and a concave image-side surface S2 at a paraxial region of the first lens element L1.
The second lens element L2 with negative refractive power has a convex object-side surface S3 at a paraxial region and a concave image-side surface S4 at a paraxial region of the second lens element L2.
The third lens element L3 with positive refractive power has a convex object-side surface S5 and an convex image-side surface S6 at paraxial region of the third lens element L3.
The fourth lens element L4 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 L4.
The fifth lens element L5 with positive refractive power has a convex object-side surface S9 and an convex image-side surface S10 at paraxial region of the fifth lens element L5.
Other structures of the fourth embodiment are the same as those of the first embodiment, and reference may be made thereto.
Table 4a shows a table of characteristics of the optical system of the present embodiment, in which the reference wavelength of the focal length is 542.02nm, the refractive index and abbe number of the material are obtained by visible light having a reference wavelength of 587.6nm, the units of the Y radius, the thickness and the focal length are millimeters (mm), wherein the positive and negative values of the thickness value represent directions only, and the other parameters have the same meanings as those of the first embodiment.
TABLE 4a
Table 4b gives the coefficients of high-order terms that can be used for each aspherical mirror surface in the fourth embodiment, wherein each aspherical mirror surface type can be defined by the formula given in the first embodiment.
TABLE 4b
| Number of noodles | S3 | S4 | S8 | S9 | S10 |
| K | 1.4876E+00 | -1.1916E+00 | -2.4140E+00 | -9.5160E+00 | -1.1383E+00 |
| A4 | 5.8577E-01 | 5.4262E-02 | 7.4528E-01 | 5.1059E+00 | 2.9470E-01 |
| A6 | -2.3601E-02 | 4.1197E+00 | -3.3764E+00 | -4.3935E+01 | -2.7235E+00 |
| A8 | -1.5883E-01 | -2.3273E+01 | 1.7309E+01 | 3.3046E+02 | 2.0978E+01 |
| A10 | 2.3805E-01 | 7.2988E+01 | -8.2151E+01 | -1.7670E+03 | -9.7359E+01 |
| A12 | -1.8482E-01 | -1.4276E+02 | 2.5216E+02 | 6.1264E+03 | 2.8520E+02 |
| A14 | 8.6717E-02 | 1.7447E+02 | -3.1276E+02 | -1.3249E+04 | -5.2932E+02 |
| A16 | -2.4662E-02 | -1.2895E+02 | -3.5311E+02 | 1.7180E+04 | 6.0248E+02 |
| A18 | 3.9306E-03 | 5.2598E+01 | 1.3789E+03 | -1.2262E+04 | -3.8244E+02 |
| A20 | -2.7106E-04 | -9.0670E+00 | -1.0466E+03 | 3.7022E+03 | 1.0336E+02 |
FIG. 8 shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fourth embodiment, wherein the longitudinal spherical aberration curves represent the convergent focus deviations of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curves represent meridional imaging plane curvature and sagittal imaging plane curvature; the distortion curve represents the distortion magnitude values corresponding to different angles of view. As can be seen from the aberration diagram in fig. 8, the longitudinal spherical aberration, curvature of field, and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality.
Fifth embodiment
Referring to fig. 9 and 10, the optical system of the present embodiment, in order from an object side to an image side along an optical axis, includes:
the first lens element L1 with negative refractive power has a convex object-side surface S1 at a paraxial region and a concave image-side surface S2 at a paraxial region of the first lens element L1.
The second lens element L2 with negative refractive power has a convex object-side surface S3 at a paraxial region and a concave image-side surface S4 at a paraxial region of the second lens element L2.
The third lens element L3 with positive refractive power has a convex object-side surface S5 and an convex image-side surface S6 at paraxial region of the third lens element L3.
The fourth lens element L4 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 L4.
The fifth lens element L5 with positive refractive power has a convex object-side surface S9 and an convex image-side surface S10 at paraxial region of the fifth lens element L5.
Table 5a shows a table of characteristics of the optical system of the present embodiment, in which the reference wavelength of the focal length is 542.02nm, the refractive index and abbe number of the material are obtained by visible light having a reference wavelength of 587.6nm, the units of the Y radius, the thickness and the focal length are millimeters (mm), wherein positive and negative values of the thickness value represent directions only, and the other parameters have the same meanings as those of the first embodiment.
TABLE 5a
Table 5b shows the high-order term coefficients that can be used for each aspherical mirror surface in the fifth embodiment, wherein each aspherical mirror surface type can be defined by the formula given in the first embodiment.
TABLE 5b
FIG. 10 shows a longitudinal spherical aberration curve, an astigmatism curve and a distortion curve of the optical system of the fifth embodiment, wherein the longitudinal spherical aberration curves represent convergent focus deviations of light rays of different wavelengths after passing through respective lenses of the optical system; the astigmatism curves represent meridional imaging plane curvature and sagittal imaging plane curvature; the distortion curve represents the distortion magnitude values corresponding to different angles of view. As can be seen from the aberration diagram in fig. 10, the longitudinal spherical aberration, curvature of field, and distortion of the optical system are well controlled, so that the optical system of this embodiment has good imaging quality.
Table 6 shows f1 × f2 (mm) in the optical systems of the first to fifth embodiments2)、f3/f、(Rs5-Rs6)/(Rs5+Rs6)、f45/(CT5-CT4)、TTL/f、(CT3+d34)/f、Imgh/EPD、Rs3/CT2、40<(FOV f)/2 Imgh.
TABLE 6
| f1*f2(mm2) | f3/f | (Rs5-Rs6)/(Rs5+Rs6) | f45/(CT5-CT4) | |
| First embodiment | 1.143 | 0.331 | 0.461 | 1.648 |
| Second embodiment | 1.137 | 0.358 | 0.437 | 1.252 |
| Third embodiment | 1.238 | 0.315 | 0.475 | 2.852 |
| Fourth embodiment | 1.445 | 0.307 | 0.499 | 1.359 |
| Fifth embodiment | 1.100 | 0.323 | 0.447 | 1.911 |
| TTL/f | (CT3+d34)/f | Rs3/CT2 | (FOV*f)/2*Imgh(°) | |
| First embodiment | 8.749 | 19.679 | 1.681 | 2.272 |
| Second embodiment | 10.410 | 9.006 | 1.481 | 5.226 |
| Third embodiment | 9.569 | 8.138 | 1.427 | 1.920 |
| Fourth embodiment | 10.495 | 14.497 | 1.527 | 3.521 |
| Fifth embodiment | 8.326 | 12.076 | 1.556 | 1.926 |
As can be seen from table 6, the optical systems of the first to fifth embodiments all satisfy the following relations: 8mm2<f1*f2<11.5mm2、3.5<f3/f<8、1<(Rs5-Rs6)/(Rs5+Rs6)<4、3<f45/(CT5-CT4)<4、13.5<TTL/f<18、3<(CT3+d34)/f<4.5、7<Rs3/CT2<10.5、40°<(FOV*f)/2*Imgh<55°。
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims (11)
1. An optical system, comprising, in order from an object side to an image side along an optical axis:
a first lens element with negative refractive power;
a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface;
the third lens element with positive refractive power has a convex object-side surface and a convex image-side surface at a paraxial region;
a fourth lens element with negative refractive power having a convex object-side surface and a concave image-side surface;
a fifth lens element with positive refractive power having convex object-side and image-side surfaces at paraxial region;
the optical system satisfies the relation:
8mm2<f1*f2<11.5mm2；
wherein f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.
2. The optical system of claim 1, wherein at least one lens of the optical system is a plastic aspheric lens, and at least one lens satisfies the relationship:
Vd<28；
and Vd is the Abbe number of the optical system.
3. The optical system of claim 1, wherein the optical system satisfies the relationship:
3.5<f3/f<8；
wherein f3 is an effective focal length of the third lens, and f is an effective focal length of the optical system.
4. The optical system of claim 1, wherein the optical system satisfies the relationship:
1<(Rs5-Rs6)/(Rs5+Rs6)<4；
wherein Rs5 is a radius of curvature of the object-side surface of the third lens element at the optical axis, and Rs6 is a radius of curvature of the image-side surface of the third lens element at the optical axis.
5. The optical system of claim 1, wherein the optical system satisfies the relationship:
3<f45/(CT5-CT4)<4；
wherein f45 is a combined focal length of the fourth lens element and the fifth lens element, CT4 is an optical thickness of the fourth lens element, and CT5 is an optical thickness of the fifth lens element.
6. The optical system of claim 1, wherein the optical system satisfies the relationship:
13.5<TTL/f<18；
wherein, TTL is the total length of the optical system, and f is the effective focal length of the optical system.
7. The optical system of claim 1, wherein the optical system satisfies the relationship:
3<(CT3+d34)/f<4.5；
wherein CT3 is the thickness of the third lens on the optical axis, d34 is the air space between the third lens and the fourth lens on the optical axis, and f is the effective focal length of the optical system.
8. The optical system of claim 1, wherein the optical system satisfies the relationship:
7<Rs3/CT2<10.5；
wherein Rs3 is the radius of curvature of the object-side surface of the second lens at the optical axis, and CT2 is the thickness of the second lens at the optical axis.
9. The optical system of claim 1, wherein the optical system satisfies the relationship:
40°<(FOV*f)/2*Imgh<55°；
wherein FOV is the maximum field angle of the optical system, f is the effective focal length of the optical system, and Imgh is the image height corresponding to half of the maximum field angle of the optical system.
10. A lens module comprising a barrel, a photosensitive element and the optical system according to any one of claims 1 to 9, wherein the first to fifth lenses of the optical system are mounted in the barrel, and the photosensitive element is disposed on an image side of the optical system.
11. An electronic apparatus, characterized in that the electronic apparatus comprises a housing and the lens module according to claim 10, the lens module being disposed in the housing.
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| CN202111238493.9A CN113885174A (en) | 2021-10-25 | 2021-10-25 | Optical system, lens module and electronic equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111238493.9A CN113885174A (en) | 2021-10-25 | 2021-10-25 | Optical system, lens module and electronic equipment |
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2021
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