CN210142230U - Low distortion optical system - Google Patents
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- CN210142230U CN210142230U CN201921298027.8U CN201921298027U CN210142230U CN 210142230 U CN210142230 U CN 210142230U CN 201921298027 U CN201921298027 U CN 201921298027U CN 210142230 U CN210142230 U CN 210142230U
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Abstract
The utility model relates to a low distortion optical system, include: a first lens (L1) having negative power, a second lens (L2) having negative power, a third lens (L3) having positive power, a fourth lens (L4) having positive power, a fifth lens (L5) having positive power, a sixth lens (L6) having negative power, a seventh lens (L7) having positive power, and an eighth lens (L8) having positive power, which are arranged in order from the object side to the image side along the optical axis; wherein the fifth lens and the sixth lens are combined to form a cemented lens group having positive optical power. The utility model discloses a low distortion optical system can realize the 110 wide-angle image capture of horizontal direction, compromises the low distortion performance that system's optical distortion is less than 10% simultaneously, and image deformation is little, and the image picture is more true.
Description
Technical Field
The utility model relates to an optical imaging field especially relates to a low distortion optical system.
Background
With the development of information technology, video conferences are widely applied to remote traffic management of enterprises. Video conferencing is increasingly concerned about the realism and interactivity of conferences. In a video conference, an imaging optical system for shooting is a very important component, and the selection of the imaging optical system has a significant influence on the using effect of the video conference.
The video conference lens commonly used at present has the defects that: a horizontal field angle is small, image capturing capability is limited in the horizontal direction, and a wide-angle lens having a field angle of more than 100 ° generally has a serious image distortion. In view of the deficiencies of the prior art, the present invention provides a low distortion optical system to solve the above technical problems.
Disclosure of Invention
An object of the utility model is to solve above-mentioned problem, provide a low distortion optical system.
To achieve the above object, the present invention provides a low distortion optical system, including: a first lens having negative power, a second lens having negative power, a third lens having positive power, a fourth lens having positive power, a fifth lens having positive power, a sixth lens having negative power, a seventh lens having positive power, and an eighth lens having positive power, which are arranged in this order from the object side to the image side along the optical axis;
wherein the fifth lens and the sixth lens are combined to form a cemented lens group having positive optical power.
According to an aspect of the present invention, the second lens, the third lens, the seventh lens and the eighth lens are aspheric lenses.
According to an aspect of the invention, the second lens is a convex-concave lens, and the eighth lens is a convex-convex lens.
According to one aspect of the present invention, the effective focal length f1 of the front lens group composed of the first lens, the second lens and the third lens and the effective focal length f of the low distortion optical system satisfy the following relational expression of-2.12. ltoreq. f 1/f. ltoreq. 1.62.
According to an aspect of the present invention, the effective focal length f2 of the rear lens group composed of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the low distortion optical system satisfy the following relation that 2.31 ≤ f2/f ≤ 3.07.
According to the utility model discloses an aspect, low distortion optical system's effective focal length f with low distortion optical system's half image height h satisfies the relational expression: f/h is more than or equal to 0.6 and less than or equal to 1.3.
According to an aspect of the present invention, the abbe number Vd5 of the fifth lens satisfies the following relation: vd5 is more than or equal to 60.
According to an aspect of the present invention, the low distortion optical system focal length f and the distance from the image side surface center of the eighth lens to the image plane satisfy the following relational expression for BFL: f/BFL is more than or equal to 0.58 and less than or equal to 1.4.
According to an aspect of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are composed of a glass lens and a plastic lens.
According to the utility model discloses a scheme is through the improvement design to each lens concavity and focal power among the optical system to establish second lens, third lens, seventh lens and eighth lens into aspheric lens, can realize 110 wide-angle image capture of horizontal direction, compromise simultaneously that system optical distortion is less than 10% low distortion performance, the image deformation is little, and the image picture is more true.
According to the utility model discloses a scheme, optical system's effective focal length f and half high h of image satisfy the relational expression: f/h is more than or equal to 0.6 and less than or equal to 1.3. The main ray angle CRA of the maximum view field can meet the relational expression that CRA is less than 9 degrees, the CMOS/CCD of a plurality of photosensitive chips can be compatible, the application prospect is wide, and the market competitiveness is improved.
According to the utility model discloses a scheme, through using glass lens and plastic lens collocation, has effectively rectified optical system's distortion to make optical system satisfy the high definition formation of image of 800 ten thousand pixels, and do not virtual burnt at-40 ℃ -80 ℃ temperature range. And the total length of the optical system is less than 22mm, the volume is small, and low cost is favorably realized.
According to one aspect of the utility model, the effective focal length f1 of the front lens group composed of the first lens, the second lens and the third lens and the effective focal length f of the low distortion optical system satisfy the following relational expression that-2.12 is less than or equal to f1/f is less than or equal to-1.62. The effective focal length f2 of the rear lens group consisting of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the low-distortion optical system satisfy the following relational expression that f2/f is more than or equal to 2.31 and less than or equal to 3.07. Such a power design is advantageous for obtaining high resolution of the optical system.
According to an aspect of the present invention, the abbe number Vd5 of the fifth lens satisfies the following relation: vd5 is more than or equal to 60. The method is beneficial to the correction of chromatic aberration of the optical system and realizes high resolution.
According to the utility model discloses a scheme, the distance of image side surface center to image plane of low distortion optical system focus f and eighth lens satisfies following relational expression for BFL: f/BFL is more than or equal to 0.58 and less than or equal to 1.4. The optical total length of the optical system is smaller, and the tolerance sensitivity is smaller.
Drawings
Fig. 1 is a structural view schematically showing a low distortion optical system according to the present invention;
fig. 2 is a diagram schematically illustrating a Modulation Transfer Function (MTF) analysis of a low distortion optical system according to a first embodiment of the present invention;
fig. 3 is a defocus graph schematically showing a low distortion optical system according to a first embodiment of the present invention;
fig. 4 is a field curvature distortion diagram schematically illustrating a low distortion optical system according to a first embodiment of the present invention;
fig. 5 is a diagram schematically showing an analysis of a Modulation Transfer Function (MTF) of a low distortion optical system according to a second embodiment of the present invention;
fig. 6 is a defocus graph schematically showing a low distortion optical system according to a second embodiment of the present invention;
fig. 7 is a field curvature distortion diagram schematically showing a low distortion optical system according to a second embodiment of the present invention;
fig. 8 is a diagram schematically showing an analysis of a Modulation Transfer Function (MTF) of a low distortion optical system according to a third embodiment of the present invention;
fig. 9 is a defocus graph schematically showing a low distortion optical system according to a third embodiment of the present invention;
fig. 10 is a field curvature distortion diagram schematically showing a low distortion optical system according to a third embodiment of the present invention;
fig. 11 is a diagram schematically illustrating a Modulation Transfer Function (MTF) analysis of a low distortion optical system according to a fourth embodiment of the present invention;
fig. 12 is a defocus graph schematically showing a low distortion optical system according to a fourth embodiment of the present invention;
fig. 13 is a field curvature distortion diagram schematically showing a low distortion optical system according to a fourth embodiment of the present invention;
fig. 14 is a diagram schematically illustrating a Modulation Transfer Function (MTF) analysis of a low distortion optical system according to a fifth embodiment of the present invention;
fig. 15 is a defocus graph schematically showing a low distortion optical system according to a fifth embodiment of the present invention;
fig. 16 is a field curvature distortion diagram schematically showing a low distortion optical system according to a fifth embodiment of the present invention.
Detailed Description
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 embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
In describing embodiments of the present invention, the terms "longitudinal," "lateral," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and other terms are used in an orientation or positional relationship shown in the associated drawings for convenience in describing the invention and for simplicity in description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the invention.
The present invention will be described in detail with reference to the accompanying drawings and specific embodiments, which are not repeated herein, but the present invention is not limited to the following embodiments.
Fig. 1 is a structural view schematically showing a low distortion optical system according to the present invention. As shown in fig. 1, the low distortion optical system of the present invention includes: a first lens L1 having negative power, a second lens L2 having negative power, a third lens L3 having positive power, a stop STO, a fourth lens L4 having positive power, a fifth lens L5 having positive power, a sixth lens L6 having negative power, a seventh lens L7 having positive power, and an eighth lens L8 having positive power, which are arranged in this order from the object side to the image side along the optical axis. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are composed of glass lenses and plastic lenses.
In the utility model discloses in, fifth lens and the bonding of sixth lens constitute the cemented lens group that has positive focal power. The second lens L2 is a convex-concave lens, and the eighth lens L8 is a convex-convex lens.
The utility model discloses in, second lens L2, third lens L3, seventh lens L7 and eighth lens L8 are aspheric lens, are playing the primary role in correcting the distortion aberration.
Through the design, the large-angle image capture of 110 degrees in the horizontal direction can be realized, the low distortion performance of the system with the optical distortion lower than 10 percent is considered, the image deformation is small, and the imaging picture is more real.
In addition, the effective focal length f1 of the front lens group consisting of the first lens L1, the second lens L2 and the third lens L3 and the effective focal length f of the low distortion optical system satisfy the following relational expression of-2.12. ltoreq. f 1/f. ltoreq-1.62. The effective focal length f2 of the rear lens group consisting of the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 and the effective focal length f of the low-distortion optical system satisfy the following relational expression that f2/f is more than or equal to 2.31 and less than or equal to 3.07. Such a power design is advantageous for obtaining high resolution of the optical system.
In the present invention, the abbe number Vd5 of the fifth lens L5 satisfies the following relation: vd5 is more than or equal to 60. The method is beneficial to the correction of chromatic aberration of the optical system and realizes high resolution.
The low-distortion optical system focal length f and the distance BFL from the center of the image-side surface of the eighth lens L8 to the image plane satisfy the following relationship: f/BFL is more than or equal to 0.58 and less than or equal to 1.4. The optical system satisfies the above formula relationship, so that the optical total length of the optical system is smaller and the tolerance sensitivity is smaller.
The utility model discloses in, optical system's effective focal length f and half high h of the image satisfy the relational expression: f/h is more than or equal to 0.6 and less than or equal to 1.3. The main ray angle CRA of the maximum view field of the optical system of the utility model can satisfy the relational expression that CRA is less than 9 degrees, can be compatible with a plurality of photosensitive chips COMS/CCD, has wide application prospect and improves the market competitiveness.
The utility model discloses in, use glass lens and plastic lens collocation, can make the utility model discloses an optical system satisfies the high definition formation of image of 800 ten thousand pixels, and does not virtual burnt at-40 ℃ -80 ℃ temperature range. The distortion of the optical system is effectively corrected, the total length of the optical system is less than 22mm, the size is small, and low cost is favorably realized.
The low distortion optical system according to the present invention will be specifically described below by giving five sets of embodiments according to the above-described arrangement of the present invention. Because according to the utility model discloses a total eight lenses of low distortion optical system, wherein, fifth lens 5 and sixth lens 6 constitute the cemented lens group, so eight lens plus diaphragm STO and the face of dull and stereotyped filter IR and chip protection glass CG between imaging face IMA and the lens, total 20 faces. The 20 faces are arranged in sequence according to the structure sequence of the present invention, and for convenience of description, the 20 faces are numbered as S1 to S20, where S7 is the stop STO, and S11 is the cemented face of the fifth lens 5 and the sixth lens 6. Further, in the following embodiments, the aspherical lens surface type satisfies the following formula:
in the formula, z is the axial distance from the curved surface to the vertex at the position which is along the direction of the optical axis and is vertical to the optical axis by the height h; c represents the curvature at the apex of the aspherical surface; k is a conic coefficient; a4, a6, A8, a10 and a12 respectively represent aspheric coefficients of fourth, sixth, eighth, tenth and twelfth orders. Five sets of embodiment data are as in table 1 below:
TABLE 1
The following embodiments are each explained based on the optical system configuration shown in fig. 1.
The first implementation mode comprises the following steps:
the total optical length TTL of the optical system is 21.67 mm;
the effective focal length f of the optical system is 2.28 mm;
table 2 is a parameter table of the first embodiment:
TABLE 2
In the present embodiment, the aspherical surface data is as shown in table 3 below:
TABLE 3
Fig. 2 to 4 are schematic diagrams each showing a Modulation Transfer Function (MTF) analysis diagram of a low distortion optical system according to a first embodiment of the present invention; according to the utility model discloses a out-of-focus curve graph of low distortion optical system of embodiment one; according to the present invention, the field curvature distortion diagram of the low distortion optical system is shown.
By optimizing the above parameter values, the resolution of the present embodiment can reach 800 ten thousand pixels, and the resolution of the lens can be ensured to be the same as that of the normal temperature without refocusing under the ambient temperature change of-40 ℃ to 80 ℃. Referring to fig. 4, the optical distortion is 8.2%, and a low distortion effect is achieved.
The second embodiment:
the total optical length TTL of the optical system is 21.84 mm;
the effective focal length f of the optical system is 2.52 mm;
table 4 is a parameter table of embodiment two:
TABLE 4
In the present embodiment, the aspherical surface data is as shown in table 5 below:
TABLE 5
Fig. 5 to 7 are schematic diagrams each showing a Modulation Transfer Function (MTF) analysis diagram of a low distortion optical system according to a second embodiment of the present invention; according to the second embodiment of the present invention, the defocus profile of the low distortion optical system is shown; according to the second embodiment of the present invention, a field curvature distortion diagram of a low distortion optical system is provided.
By optimizing the above parameter values, the resolution of the present embodiment can reach 800 ten thousand pixels, and the resolution of the lens can be ensured to be the same as that of the normal temperature without refocusing under the ambient temperature change of-40 ℃ to 80 ℃. Referring to fig. 7, the optical distortion is 9.6%, and a low distortion effect is achieved.
The third embodiment is as follows:
the total optical length TTL of the optical system is 20.25 mm;
the effective focal length f of the optical system is 2.94 mm;
table 6 is a parameter table of the third embodiment:
TABLE 6
In the present embodiment, the aspherical surface data is as shown in table 7 below:
TABLE 7
Fig. 8 to 10 are schematic diagrams each showing a Modulation Transfer Function (MTF) analysis diagram of a low distortion optical system according to a third embodiment of the present invention; according to the third embodiment of the present invention, the defocus graph of the low distortion optical system; according to the present invention, the field curvature distortion diagram of the low distortion optical system according to the third embodiment is provided.
By optimizing the above parameter values, the resolution of the present embodiment can reach 800 ten thousand pixels, and the resolution of the lens can be ensured to be the same as that of the normal temperature without refocusing under the ambient temperature change of-40 ℃ to 80 ℃. Referring to fig. 10, the optical distortion is 7.7%, and a low distortion effect is achieved.
The fourth embodiment:
the total optical length TTL of the optical system is 19.18 mm;
the effective focal length f of the optical system is 2.79 mm;
table 8 is a parameter table of the fourth embodiment:
TABLE 8
In the present embodiment, the aspherical surface data is as shown in table 9 below:
TABLE 9
Fig. 11 to 13 are schematic diagrams each showing a Modulation Transfer Function (MTF) analysis diagram of a low distortion optical system according to a fourth embodiment of the present invention; according to the fourth embodiment of the present invention, a defocus graph of a low distortion optical system; according to the fourth embodiment of the present invention, a field curvature distortion diagram of a low distortion optical system is provided.
By optimizing the above parameter values, the resolution of the present embodiment can reach 800 ten thousand pixels, and the resolution of the lens can be ensured to be the same as that of the normal temperature without refocusing under the ambient temperature change of-40 ℃ to 80 ℃. Referring to fig. 13, the optical distortion is 6.9%, and a low distortion effect is achieved.
The fifth embodiment:
the total optical length TTL of the optical system is 19.84 mm;
the effective focal length f of the optical system is 2.40 mm;
table 10 is a parameter table of the fifth embodiment:
watch 10
In the present embodiment, the aspherical surface data is as shown in table 11 below:
TABLE 11
Fig. 14 to 16 are schematic diagrams each showing a Modulation Transfer Function (MTF) analysis diagram of a low distortion optical system according to a fifth embodiment of the present invention; according to the fifth embodiment of the present invention, a defocus graph of a low distortion optical system is shown; according to the present invention, the field curvature distortion diagram of the low distortion optical system of the fifth embodiment is provided.
By optimizing the above parameter values, the resolution of the present embodiment can reach 800 ten thousand pixels, and the resolution of the lens can be ensured to be the same as that of the normal temperature without refocusing under the ambient temperature change of-40 ℃ to 80 ℃. Referring to fig. 16, the optical distortion is 6.3%, and a low distortion effect is achieved.
The above description is only one 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. A low distortion optical system, comprising: a first lens (L1) having negative power, a second lens (L2) having negative power, a third lens (L3) having positive power, a fourth lens (L4) having positive power, a fifth lens (L5) having positive power, a sixth lens (L6) having negative power, a seventh lens (L7) having positive power, and an eighth lens (L8) having positive power, which are arranged in order from the object side to the image side along the optical axis;
wherein the fifth lens (L5) and the sixth lens (L6) are combined to form a cemented lens group having positive optical power.
2. The low distortion optical system according to claim 1, wherein the second lens (L2), the third lens (L3), the seventh lens (L7), and the eighth lens (L8) are aspherical lenses.
3. The low distortion optical system of claim 2 wherein the second lens (L2) is a convex-concave lens and the eighth lens (L8) is a convex-convex lens.
4. A low distortion optical system as set forth in one of claims 1 to 3, wherein an effective focal length f1 of a front lens group consisting of the first lens (L1), the second lens (L2) and the third lens (L3) and an effective focal length f of the low distortion optical system satisfy the following relation of-2.12. ltoreq. f 1/f. ltoreq-1.62.
5. A low distortion optical system according to any one of claims 1 to 3, wherein the effective focal length f2 of the rear lens group consisting of the fourth lens (L4), the fifth lens (L5), the sixth lens (L6), the seventh lens (L7) and the eighth lens (L8) and the effective focal length f of the low distortion optical system satisfy the following relation 2.31 ≦ f2/f ≦ 3.07.
6. A low distortion optical system as set forth in one of claims 1 to 3, wherein an effective focal length f of the low distortion optical system and a half-image height h of the low distortion optical system satisfy the relation: f/h is more than or equal to 0.6 and less than or equal to 1.3.
7. A low distortion optical system as set forth in one of claims 1 to 3, wherein an abbe number Vd5 of the fifth lens (L5) satisfies the following relation: vd5 is more than or equal to 60.
8. The low distortion optical system according to one of claims 1 to 3, wherein an effective focal length f of the low distortion optical system and a distance BFL from an image side surface center of the eighth lens (L8) to an image plane satisfy the following relation: f/BFL is more than or equal to 0.58 and less than or equal to 1.4.
9. Low distortion optical system according to one of claims 1 to 3, characterized in that a Stop (STO) is provided between the third lens (L3) and the fourth lens (L4).
10. The low distortion optical system according to one of claims 1 to 3, wherein the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4), the fifth lens (L5), the sixth lens (L6), the seventh lens (L7), and the eighth lens (L8) are composed of a glass lens and a plastic lens.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110333593A (en) * | 2019-08-12 | 2019-10-15 | 舜宇光学(中山)有限公司 | Low distorted optical system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110333593A (en) * | 2019-08-12 | 2019-10-15 | 舜宇光学(中山)有限公司 | Low distorted optical system |
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