CN209961992U - Optical system and imaging lens - Google Patents
Optical system and imaging lens Download PDFInfo
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- CN209961992U CN209961992U CN201920978235.6U CN201920978235U CN209961992U CN 209961992 U CN209961992 U CN 209961992U CN 201920978235 U CN201920978235 U CN 201920978235U CN 209961992 U CN209961992 U CN 209961992U
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Abstract
The utility model relates to an optical device field particularly, relates to an optical system and imaging lens. The optical system comprises a first lens module, a second lens module, a third lens module and a diaphragm, wherein the first lens module, the diaphragm, the second lens module and the third lens module are sequentially arranged; the first lens module has positive focal power, the second lens module has negative focal power, and the third lens module has positive focal power; the focal length of the first lens module needs to satisfy the following condition:
wherein F is the focal length of the optical system, and F1Is the focal length of the first lens module; when the focal length is adjusted, the first lens module and the third lens module are fixed, and the second lens module moves along the optical axis. The utility model discloses only need remove the second lens module at the focusing in-process, when guaranteeing the entrance pupil position, reduce focusing mechanical structure's load, be favorable to optical system and the miniaturization and the lightweight that have this optical system equipment.
Description
Technical Field
The utility model relates to an optical device field particularly, relates to an optical system and imaging lens.
Background
Imaging lenses with field angles between 40-60 are commonly referred to as standard lenses, typically employing triple or tesseral (Tessar) configurations when the focal length F-number of the lens is large, and dual gauss configurations for large aperture standard lenses with F-numbers less than 2.8.
However, as the lenses and cameras are increasingly becoming more portable, how to reduce the weight of the focusing lens group becomes an important issue.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an optical system, its mode of focusing that can pass through three lens module groups, under the condition of using less lens module, all carry out good correction with color and sedentary aberration, guaranteed excellent imaging performance, realized reducing the purpose of focusing the weight of lens group.
Another object of the present invention is to provide an imaging lens, which can reduce the weight of the lens, so that the camera is more portable.
The embodiment of the utility model is realized like this:
an optical system comprises a first lens module, a second lens module, a third lens module and a diaphragm, wherein the first lens module, the diaphragm, the second lens module and the third lens module are arranged in sequence;
the first lens module has positive focal power, the second lens module has negative focal power, and the third lens module has positive focal power;
the focal length of the first lens module needs to satisfy the following condition:
wherein F is the focal length of the optical system, and F1Is the focal length of the first lens module;
when the focal length is adjusted, the first lens module and the third lens module are fixed, and the second lens module moves along the optical axis.
In a preferred embodiment of the present invention, the first lens module includes a first positive lens, a second positive lens, a third negative lens and a fourth cemented lens group, which are sequentially disposed;
the first positive lens is located one side of the second positive lens, which is far away from the second lens module, the side of the second positive lens, which is far away from the first positive lens, is a concave surface, and the side of the third negative lens, which is close to the second positive lens, is a convex surface.
In a preferred embodiment of the present invention, the radius of curvature of the side of the second positive lens away from the first positive lens is R2bThe radius of curvature of one side of the third negative lens close to the second positive lens is R3aWherein R is2bAnd R3aThe relationship between them is:
in a preferred embodiment of the present invention, the fourth cemented lens group includes a fourth negative lens and a fifth positive lens, the fourth negative lens is disposed on a side of the fifth positive lens close to the third negative lens, and the fourth negative lens and the fifth positive lens are cemented together.
In a preferred embodiment of the present invention, at least one negative lens in the third lens module can satisfy the following condition:
1.2≤nd≤1.6
wherein n isdIs the refractive index of the medium with respect to light having a wavelength of 587.6 nm.
In a preferred embodiment of the present invention, at least one negative lens in the third lens module can satisfy the following condition:
50≤νd≤95
wherein v isdThe Abbe number of the medium with respect to a light ray having a wavelength of 587.6 nm.
In a preferred embodiment of the present invention, the third lens module includes a seventh positive lens and an eighth negative lens, and the seventh positive lens is disposed on a side of the eighth negative lens close to the second lens module;
focal length F of the seventh positive lens7Focal length F of the eighth negative lens8The relationship between them is:
in a preferred embodiment of the present invention, the optical system satisfies the following conditions:
and B is the distance between the lens surface of the third lens module far away from the second lens module and the image surface, and F is the focal length of the optical system.
In a preferred embodiment of the present invention, the second lens module includes a sixth negative lens.
The utility model also provides an imaging lens, it includes above-mentioned arbitrary optical system.
The embodiment of the utility model provides a beneficial effect is:
only the second lens module needs to be moved in the focusing process, so that the load of a focusing mechanical structure is reduced while the entrance pupil position is ensured, and the miniaturization and the light weight of the optical system and the optical system equipment are facilitated.
Through the focusing mode of the three groups of lens modules, under the condition of using less lens modules, the chromatic aberration and the Seidel pentaaberration are well corrected, and excellent imaging performance is ensured.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic structural diagram of an optical system according to an embodiment of the present invention;
fig. 2 is a color spherical aberration graph of an optical system according to an embodiment of the present invention, in which the default value without a unit is millimeter;
fig. 3 is an astigmatism and distortion diagram of an optical system provided by an embodiment of the present invention, and default values without formulation units are millimeters.
In the figure:
GP 1: a first lens module; SP: a diaphragm; GP 2: a second lens module; GP 3: a third lens module; GL: parallel glass plates; IMG: an image surface;
g1: a first positive lens; g2: a second positive lens; g3: a third negative lens; g4: a fourth negative lens; g5: a fifth positive lens; g6: a sixth negative lens; g7: a seventh positive lens; g8: and an eighth negative lens.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "first", "second", "third", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
Hereinafter, an optical system and an optical apparatus having the same according to the present invention will be described in detail based on the drawings. In the lens data, the refractive index and the focal length are values of d-line. In the optical lens related data, the unit of the length is mm, and the unit thereof will be omitted.
It is noted that the symbols used in the table and the following description are as follows:
“Si"denotes the surface number; "Ri"is the radius of curvature; ' di"is the on-axis surface distance between the ith surface and the (i + 1) th surface; "n" isd"is the refractive index; v isd"is Abbe number; "Fno" is the F number; "ω" is the half field angle. With respect to the surface number, "ASP" indicates that the surface is an aspherical surface, and with respect to the radius of curvature, "∞" indicates that the surface is a plane.
Some embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.
An optical system comprises a first lens module GP1, a second lens module GP2, a third lens module GP3 and a diaphragm SP, wherein the first lens module GP1, the diaphragm SP, the second lens module GP2 and the third lens module GP3 are sequentially arranged; the first lens module GP1 has a positive focal power, the second lens module GP2 has a negative focal power, and the third lens module GP3 has a positive focal power.
In use, the first lens module GP1 is on the object side and the third lens module GP3 is on the imaging side.
Fig. 1 is a cross-sectional view of an optical system along an optical axis according to an embodiment of the present invention, in which an arrow direction is a focusing direction.
The utility model provides an optical system is from the object side configuration first lens module GP1 that has positive focal power; an aperture stop SP; a second lens module GP2 having a negative optical power; a third lens module GP3 having a positive optical power. The second lens module GP2 moves along the optical axis during focusing, and the first lens module GP1 and the third lens module GP3 are fixed with respect to the image surface IMG.
A filter configuration of a parallel glass plate GL is arranged between the third lens module GP3 and the image surface IMG, the back intercept being the distance from the image side surface of the third lens module GP3 to the image surface IMG, wherein the parallel glass plate GL transforms into air.
The following are various numerical data regarding the optical system of the present embodiment.
Fig. 2 and 3 are aberration diagrams illustrating the optical system according to the present embodiment at infinity focus (β ═ 0.0). Referring to FIG. 2, in the diagram of spherical aberration, line A, line B and line C represent spherical aberration at d-line (wavelength 587.6nm), C-line (wavelength 656.3nm) and g-line (wavelength 435.8nm), respectively; fig. 3 is a schematic diagram illustrating astigmatism and distortion.
In the preferred embodiment of the present invention, the focal length of the first lens module GP1 should satisfy the following condition:
where F is the focal length of the optical system, and F1 is the focal length of the first lens module.
The conditional expression (1) specifies the incident angle of the light beam before the stop SP and the position of the entrance pupil.
When the combined focal length of the first lens module GP1 before the stop SP is within this range, the entrance pupil is located closer to the object side and the entrance pupil size is smaller. In the case of the same angle of view, the intersection of the principal ray and the lens is closer to the optical axis, so that the aperture of the first lens module GP1 can be designed smaller, and aberrations such as spherical aberration and distortion caused by the declination of the ray are correspondingly smaller.
If the lower limit is exceeded in the conditional expression (1), the combined focal length of the first lens module GP1 and the second lens module GP2 is too large, resulting in an increase in the total length of the optical system, which is not preferable.
On the other hand, if the upper limit is exceeded in the conditional expression (1), the combined focal power of the first lens module GP1 and the second lens module GP2 becomes too large, and the generated aberration is hard to be corrected by the third lens module GP3, which is not preferable.
In a preferred embodiment of the present invention, the first lens module GP1 includes a first positive lens G1, a second positive lens G2, a third negative lens G3 and a fourth cemented lens group; the first positive lens G1 is on the side of the second positive lens G2 away from the second lens module GP2, the side of the second positive lens G2 away from the first positive lens G1 is concave, and the side of the third negative lens G3 close to the second positive lens G2 is convex.
In the preferred embodiment of the present invention, the curvature radius of the side of the second positive lens G2 away from the first positive lens G1 is R2b, and the curvature radius of the side of the third negative lens G3 close to the second positive lens G2 is R3a, wherein the relationship between R2b and R3a is:
the conditional expression (2) specifies the distribution ratio of the optical power in the first lens module GP 1.
The utility model discloses an optical system, through satisfying conditional expression (2), can maintain good formation of image performance.
If the lower limit is exceeded in conditional expression (2), the radius of curvature of the image-side surface of the first positive lens G1 becomes too large, and as a result, spherical aberration becomes too large, which is not preferable.
On the other hand, if the upper limit is exceeded in conditional expression (2), the refractive power of the first positive lens G1 is too small, and the total optical length is lengthened, which is not preferable.
In a preferred embodiment of the present invention, the fourth cemented lens group includes a fourth negative lens G4 and a fifth positive lens G5, the fourth negative lens G4 is disposed on a side of the fifth positive lens G5 close to the third negative lens G3, and the fourth negative lens G4 and the fifth positive lens G5 are cemented together.
It should be noted that the fourth negative lens G4 and the fifth positive lens G5 may be arranged together by gluing, or they may be fixedly combined together by other means as long as the fourth negative lens G4 and the fifth positive lens G5 can be fixedly combined together.
Specifically, in the present embodiment, the second lens module GP2 includes a sixth negative lens G6.
In the preferred embodiment of the present invention, at least one negative lens of the third lens module GP3 can satisfy the following condition:
1.2≤nd≤1.6 (3)
50≤νd≤95 (4)
where nd and vd are respectively the refractive index and Abbe number of the medium with respect to light having a wavelength of 587.6 nm.
According to the conditional expression (3) and the conditional expression (4), the magnification chromatic aberration and the position chromatic aberration generated by the lens module on the diaphragm object side can be reduced, the chromatic aberration generated by the lens modules before and after the diaphragm is balanced, and the imaging performance of the lens is improved.
The refractive index and abbe number of the negative lens are respectively specified by the conditional expressions (3) and (4), and the positional chromatic aberration and the chromatic aberration of magnification after the second lens module GP2 are determined by the values specified by the conditional expressions, which are important factors affecting the imaging performance.
If the lower limit of the conditional expression (3) and the upper limit of the conditional expression (4) are exceeded, the positional chromatic aberration and the spherical aberration generated in the positive lens are not sufficiently corrected, and the imaging performance is deteriorated, which is not preferable.
If the upper limit of the conditional expression (3) and the lower limit of the conditional expression (4) are exceeded, the positional chromatic aberration and the spherical aberration generated in the positive lens are excessively corrected, and the imaging performance is deteriorated, which is not preferable.
In the preferred embodiment of the present invention, the third lens module GP3 includes a seventh positive lens G7 and an eighth negative lens G8, the seventh positive lens G7 is disposed on the side of the eighth negative lens G8 close to the second lens module GP 2; the relationship between the focal length F7 of the seventh positive lens G7 and the focal length F8 of the eighth negative lens G8 is:
the conditional expression (5) specifies the light incident angle of the positive lens in the third lens module GP3 according to the conditional expression (5).
The utility model discloses an imaging lens through satisfying conditional expression (5), can maintain good imaging performance.
If the lower limit is exceeded in conditional expression (5), the combined power of the cemented lens becomes too large, resulting in too large spherical aberration, and excessive spherical aberration correction, which is not preferable.
On the other hand, if the upper limit of the amount is exceeded in conditional expression (5), the combined power of the cemented lens is too small, and the positive spherical aberration is too small, resulting in insufficient spherical aberration correction, which is not preferable.
In a preferred embodiment of the present invention, the optical system satisfies the following conditions:
wherein Bf is a distance between a lens surface of the third lens module away from the second lens module and the image surface IMG, and F is a focal length of the optical system.
High optical performance is achieved according to conditional expression (6) while ensuring the back intercept of an interchangeable lens suitable for use in a single-lens reflex camera and a photocopy lens.
If the lower limit is exceeded in conditional expression (6), the back intercept becomes too short with respect to the focal length of the optical system, so that it becomes difficult to obtain an optical system suitable for an interchangeable lens for a single-lens reflex camera and a photocopy lens, and therefore, it is not preferable.
On the other hand, if the upper limit is exceeded in conditional expression (6), the back intercept becomes relatively too long with respect to the focal length of the optical system, the refractive power distribution becomes further away from the symmetric type, and therefore it is difficult to correct distortion and high optical performance cannot be achieved, and therefore it is also not preferable.
In the preferred embodiment of the present invention, when the focal length is adjusted, the first lens module GP1 and the third lens module GP3 are fixed, and the second lens module GP2 moves along the optical axis.
By using the optical structure, only the second lens module GP2 needs to be moved in the focusing process, and the second lens module GP2 is very light and convenient in structure, so that the load of a focusing mechanical structure is reduced while the entrance pupil position is ensured, and the miniaturization and the light weight of an optical system and equipment with the optical system are facilitated.
The utility model also provides an imaging lens, its optical system who includes above-mentioned arbitrary item.
The embodiment of the utility model provides a beneficial effect is:
only the second lens module needs to be moved in the focusing process, so that the load of a focusing mechanical structure is reduced while the entrance pupil position is ensured, and the miniaturization and the light weight of the optical system and the optical system equipment are facilitated.
Through the focusing mode of the three groups of lens modules, under the condition of using less lens modules, the chromatic aberration and the Seidel pentaaberration are well corrected, and excellent imaging performance is ensured.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An optical system is characterized by comprising a first lens module, a second lens module, a third lens module and a diaphragm, wherein the first lens module, the diaphragm, the second lens module and the third lens module are arranged in sequence;
the first lens module has positive focal power, the second lens module has negative focal power, and the third lens module has positive focal power;
the focal length of the first lens module needs to satisfy the following condition:
wherein F is the focal length of the optical system, and F1Is the focal length of the first lens module;
when the focal length is adjusted, the first lens module and the third lens module are fixed, and the second lens module moves along the optical axis.
2. The optical system of claim 1 wherein the first lens module comprises a first positive lens, a second positive lens, a third negative lens and a fourth cemented lens group arranged in series;
the first positive lens is located one side of the second positive lens, which is far away from the second lens module, the side of the second positive lens, which is far away from the first positive lens, is a concave surface, and the side of the third negative lens, which is close to the second positive lens, is a convex surface.
3. The optical system according to claim 2, wherein a side of the second positive lens remote from the first positive lens has a radius of curvature R2bThe radius of curvature of one side of the third negative lens close to the second positive lens is R3aWherein R is2bAnd R3aThe relationship between them is:
4. the optical system of claim 2 wherein said fourth cemented lens group includes a fourth negative lens and a fifth positive lens, said fourth negative lens being disposed on a side of said fifth positive lens adjacent to said third negative lens, said fourth negative lens and said fifth positive lens being cemented together.
5. The optical system of claim 1, wherein at least one negative lens of the third lens module satisfies the following condition:
1.2≤nd≤1.6
wherein n isdIs the refractive index of the medium with respect to light having a wavelength of 587.6 nm.
6. The optical system of claim 1, wherein at least one negative lens of the third lens module satisfies the following condition:
50≤νd≤95
wherein v isdThe Abbe number of the medium with respect to a light ray having a wavelength of 587.6 nm.
7. The optical system according to claim 1, wherein the third lens module includes a seventh positive lens and an eighth negative lens, the seventh positive lens being disposed on a side of the eighth negative lens close to the second lens module;
focal length F of the seventh positive lens7Focal length F of the eighth negative lens8The relationship between them is:
8. the optical system according to claim 1, characterized in that the following condition is satisfied:
and B is the distance between the lens surface of the third lens module far away from the second lens module and the image surface, and F is the focal length of the optical system.
9. The optical system of claim 1, wherein the second lens module comprises a sixth negative lens.
10. An imaging lens, characterized by comprising the optical system of any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920978235.6U CN209961992U (en) | 2019-06-26 | 2019-06-26 | Optical system and imaging lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920978235.6U CN209961992U (en) | 2019-06-26 | 2019-06-26 | Optical system and imaging lens |
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| CN209961992U true CN209961992U (en) | 2020-01-17 |
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| CN201920978235.6U Expired - Fee Related CN209961992U (en) | 2019-06-26 | 2019-06-26 | Optical system and imaging lens |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110261999A (en) * | 2019-06-26 | 2019-09-20 | 深圳市永诺摄影器材股份有限公司 | Optical system and imaging lens |
| CN112505879A (en) * | 2020-11-18 | 2021-03-16 | 西安玄瑞光电科技有限公司 | Wide-field-of-view long-focus high-resolution lens |
-
2019
- 2019-06-26 CN CN201920978235.6U patent/CN209961992U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110261999A (en) * | 2019-06-26 | 2019-09-20 | 深圳市永诺摄影器材股份有限公司 | Optical system and imaging lens |
| CN112505879A (en) * | 2020-11-18 | 2021-03-16 | 西安玄瑞光电科技有限公司 | Wide-field-of-view long-focus high-resolution lens |
| CN112505879B (en) * | 2020-11-18 | 2023-11-24 | 西安玄瑞光电科技有限公司 | Wide-view-field long-focus high-resolution lens |
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