CN111694135A - Big wide angle video camera lens of focus 8mm - Google Patents
Big wide angle video camera lens of focus 8mm Download PDFInfo
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- CN111694135A CN111694135A CN202010680371.4A CN202010680371A CN111694135A CN 111694135 A CN111694135 A CN 111694135A CN 202010680371 A CN202010680371 A CN 202010680371A CN 111694135 A CN111694135 A CN 111694135A
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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
Abstract
The invention discloses a large wide-angle video lens with a focal length of 8mm, which sequentially comprises the following components from an object side to an image side: a first lens group having positive refractive power and fixed in position; a second lens group having positive power and movable in position along the optical axis direction; the first lens group comprises a first negative lens group and a second negative lens group, the first negative lens group comprises at least three negative lenses, the second negative lens group comprises a positive and negative cemented lens with negative focal power and a negative and positive cemented lens with positive focal power, the first lens group comprises three negative lenses, so that the lens has a large wide angle, the light transmission amount and the resolution of the edge part of the lens can be increased, two cemented lenses matched with each other are arranged, and chromatic aberration and distortion can be corrected.
Description
Technical Field
The invention relates to the technical field of lenses, in particular to a large wide-angle video lens with a focal length of 8 mm.
Background
With the rise of video shooting and the vigorous development of the video industry in recent years, the demand of video lenses is more and more large, the most important thing for video shooting is that the picture is clear, the light flux is high, and the distortion of objects is reduced by small distortion, but the existing lenses have the defects of large distortion, small light flux caliber, insufficient resolution of edge field of view and the like, and the high requirement of video shooting cannot be met.
Disclosure of Invention
The invention aims to provide a large wide-angle video lens with a focal length of 8mm, wherein a first lens group of the large wide-angle video lens is provided with three negative lenses, so that the lens has a large wide angle, the light transmission quantity and the resolution of the edge part of the lens can be increased, two matched cemented lenses are arranged, chromatic aberration and distortion can be corrected, and the problems of low resolution of the edge field of view and easy distortion of an image of the conventional lens are solved.
In order to achieve the purpose, the invention adopts the following technical scheme:
a large wide-angle video lens with a focal length of 8mm, comprising in order from an object side to an image side: a first lens group, an iris diaphragm and a second lens group;
the first lens group has positive focal power and is fixed in position;
the second lens group has positive focal power and can move along the direction of the optical axis;
the first lens group comprises a first negative lens group and a second negative lens group, the first negative lens group comprises at least three negative lenses, and the second negative lens group comprises a positive and negative cemented lens with negative focal power and a negative and positive cemented lens with positive focal power;
the first lens group and the second lens group satisfy the following formula:
0.5<f1/f2<2；2<f12/f1<7；
wherein f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, and f12 represents the focal length of the second negative lens group.
Therefore, the first negative lens group of the first lens group is provided with three negative lenses, so that the lens has a large wide angle, the light flux and the resolution of the edge part of the lens can be increased, the two matched cemented lenses are arranged, the chromatic aberration and the distortion can be corrected, the focal length value of the first lens group and the focal length value of the second lens group meet the corresponding relation of 0.5< f1/f2<2, so that the optical system has enough rear working distance and meets the practical application requirements; the focal length value of the second negative lens group and the total focal length value of the first lens group meet the specific value relation of 2< f12/f1<7, so that the angle of a visual field which can be borne by the system is ensured, and the phase difference correction of the full visual field is facilitated.
In some embodiments, the second lens group includes a negative positive cemented lens of negative power, and a triple cemented lens of positive power.
Therefore, the cemented lens can correct chromatic aberration, can effectively balance coma, astigmatism and chromatic aberration of the front lens group and the rear lens group, greatly reduces the sensitivity of the fit tolerance of the front lens group and the rear lens group, and can be provided with a plurality of cemented lens combinations to further improve chromatic aberration.
In some embodiments, the first negative lens group comprises a first lens, a second lens, a third lens, and a fourth lens, the second lens, the third lens, and the fourth lens each having a negative optical power;
the mirror surface of each lens of the first negative lens group is curved toward the object side.
Therefore, the first negative lens group consisting of the negative lenses can enable the total coma aberration and astigmatism to be small, and the tolerance sensitivity of the front and rear lens groups can be reduced. More than three negative lenses may also be provided to further improve the field of view and reduce coma and astigmatism.
In some embodiments, the refractive index of the fifth lens element and/or the sixth lens element of the first lens group is between 1.8 and 2.0.
Therefore, the refractive index of the fifth lens or the sixth lens is only set to be between 1.8 and 2.0, or the refractive indexes of the fifth lens and the sixth lens are both set to be between 1.8 and 2.0, and the larger refractive index is beneficial to reducing the aperture and the volume of the lenses.
In some embodiments, the refractive index of the seventh lens element and/or the eighth lens element of the first lens group is between 1.9 and 2.0.
Therefore, the refractive index of the seventh lens or the eighth lens can be only set to be between 1.9 and 2.0, or the refractive index of the seventh lens and the refractive index of the eighth lens can be both set to be between 1.9 and 2.0, and the larger refractive index is beneficial to reducing the aperture and the volume of the lenses.
In some embodiments, the third cemented lens of the second lens group includes at least one lens having a refractive index between 2.0 and 2.2.
Therefore, the sixteenth lens is preferable, and the refractive indexes of the rest two lenses can be set between 2.0 and 2.2, which is beneficial to reducing the aperture and the volume of the lens.
In some embodiments, the abbe number of the second lens group including at least three lenses is between 80 and 90.
Thus, the abbe numbers of the twelfth, thirteenth and fifteenth lenses are preferably between 80 and 90, which is advantageous for reducing dispersion. The remaining lenses may also be suitably raised in abbe number, or set between 80 and 90, to further reduce dispersion.
In some embodiments, the refractive index of the first lens group including at least three lenses is between 1.9 and 1.98.
Therefore, the refractive indexes of the second, fourth and seventh lenses are preferably between 1.9 and 1.98, which is beneficial to reducing the aperture and volume of the lenses so as to realize a compact optical structure. The remaining lenses may also be suitably refractive index raised, or set between 1.9 and 1.98.
In some embodiments, the total length between the first mirror and the last mirror of the lens is between 70 mm and 77 mm, and the maximum aperture of the lens is between 50 mm and 55 mm.
Therefore, the lens has compact structure, larger caliber and improved light transmission quantity.
In some embodiments, the back working distance of the lens is BFL, the focal length of the lens is f, and the following equation is satisfied: 2< BFL/f < 5.
Therefore, the lens adopts a reverse long-distance light path structure, and the ratio relation can ensure enough rear working distance.
The invention has the beneficial effects that: the first negative lens group of the first lens group is provided with three negative lenses, so that the lens has a large wide angle, the light flux and the resolution of the edge part of the lens can be increased, the mirror surfaces of the three lenses are all bent towards the object side and are crescent, the total coma and astigmatism can be small, and the tolerance sensitivity of the front and rear lens groups can be reduced;
moreover, the second negative lens group is provided with two matched cemented lenses which can correct chromatic aberration and distortion,
moreover, the second lens is provided with three cemented lenses, so that the coma aberration, astigmatism and chromatic aberration of the front and rear lens groups can be effectively balanced, and the sensitivity of the fit tolerance of the front and rear lens groups is greatly reduced;
finally, some lenses are properly arranged to have higher refractive index and Abbe number, so that compactness is improved and dispersion is reduced.
Drawings
FIG. 1 is a block diagram of a large wide-angle video lens with a focal length of 8mm according to the present invention;
FIG. 2 is an axial coloring differential view of a large wide-angle video lens with a focal length of 8mm according to the present invention;
FIG. 3 is a schematic diagram of vertical axis chromatic aberration of a large wide-angle video lens with a focal length of 8mm according to the present invention;
FIG. 4 is a schematic diagram of curvature of field distortion of a large wide-angle video lens with a focal length of 8mm according to the present invention;
FIG. 5 is a schematic diagram of the light aberration of a large wide-angle video lens with a focal length of 8mm according to the present invention;
FIG. 6 is a schematic diagram of a diffuse spot of a large wide-angle video lens with a focal length of 8mm according to the present invention;
FIG. 7 is a schematic MTF diagram of a large wide-angle video lens with a focal length of 8mm according to the present invention;
FIG. 8 is a schematic diagram of MTF and field of view of a large wide-angle video lens with a focal length of 8mm according to the present invention;
wherein: g1-first lens group; g2-second lens group; g11 — first negative lens set; g12 — a second set of negative lenses; l1-first lens; l2-second lens; l3-third lens; l4-fourth lens; l5-fifth lens; l6-sixth lens; l7-seventh lens; l8-eighth lens; l9-ninth lens; l10-tenth lens; l11-eleventh lens; l12-twelfth lens; l13-thirteenth lens; l14-fourteenth lens; l15-the fifteenth lens; l16-sixteenth lens; l17-seventeenth lens; l18-eighteenth lens.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Referring to fig. 1, a large wide-angle video lens with a focal length of 8mm, the lens comprising, in order from an object side to an image side: a first lens group G1, an iris STO, and a second lens group G2;
the first lens group G1 has positive refractive power and is fixed in position;
the second lens group G2 has positive power and is movable in position in the optical axis direction;
the first lens group G1 includes a first negative lens group G11 and a second negative lens group G12, the first negative lens group G11 includes at least three negative lenses, and the second negative lens group G12 includes a negative and positive cemented lens of negative power and a negative and positive cemented lens of positive power;
the first lens group G1 and the second lens group G2 satisfy the following formula:
0.5<f1/f2<2；2<f12/f1<7；
where f1 represents the focal length value of the first lens group G1, f2 represents the focal length value of the second lens group G2, and f12 represents the focal length value of the second negative lens group G12.
Further, the second lens group G2 includes a negative positive cemented lens of negative power, and a triple cemented lens of positive power.
Further, the triple cemented lens is formed by a negative lens, a positive lens and a negative lens which are cemented together, i.e. a fourteenth lens L14, a fifteenth lens L15 and a sixteenth lens L16.
Further, the first negative lens group G11 includes a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4, and the second lens L2, the third lens L3 and the fourth lens L4 all have negative power;
the mirror surface of each lens of the first negative lens group G11 is curved in the object-side direction.
Further, the refractive index of the fifth lens L5 and/or the sixth lens L6 of the first lens group G1 is between 1.8 and 2.0.
Further, the refractive index of the seventh lens L7 and/or the eighth lens L8 of the first lens group G1 is between 1.9 and 2.0.
In a further description, the third cemented lens of the second lens group G2 includes at least one lens with a refractive index between 2.0 and 2.2.
In a further illustration, the second lens group G2 includes at least three lenses having abbe numbers between 80 and 90.
In a further illustration, the refractive index of the first lens group G1 includes at least three lenses between 1.9 and 1.98.
Further, the total length from the first mirror surface to the last mirror surface of the lens is between 70 mm and 77 mm, and the maximum aperture of the lens is between 50 mm and 55 mm.
Further, the back working distance of the lens is BFL, the focal length of the lens is f, and the following equation is satisfied: 2< BFL/f < 5.
The working principle is as follows:
the lens comprises a first lens group G1 with positive focal power and a second lens group G2 with positive focal power, wherein the second lens group G2 can move along an optical axis to zoom and magnify, and the lens has a focal length of 8 mm.
The first lens group G1 includes a first negative lens group G11 and a second negative lens group G12, the first negative lens group G11 includes a first lens L1 with positive focal power, a second lens L2 with negative focal power, a third lens L3 with negative focal power and a fourth lens L4 with negative focal power, wherein the first lens L1 has a larger aperture, so that the lens has a larger wide angle and a larger light transmission amount, and the mirror surfaces of the second lens L2, the third lens L3 and the fourth lens L4 are all curved toward the object side and are approximately crescent-shaped, thereby on one hand, a large field angle can be achieved, and on the other hand, the back focal length can be effectively increased.
The second negative lens group G12 includes a fifth lens L5 with positive focal power, a sixth lens L6 with negative focal power, a seventh lens L7 with negative focal power, an eighth lens L8 with positive focal power, and a ninth lens L9 with positive focal power, wherein the fifth lens L5 and the sixth lens L6 are cemented into a cemented lens, and the seventh lens L7 and the eighth lens L8 are cemented into a cemented lens, which are combined to facilitate correction of chromatic aberration and distortion and reduce distortion.
The second lens group G2 includes a tenth lens L10 with positive power, an eleventh lens L11 with negative power, a twelfth lens L12 with positive power, a thirteenth lens L13 with positive power, a fourteenth lens L14 with negative power, a fifteenth lens L15 with positive power, a sixteenth lens L16 with negative power and a seventeenth lens L17 with positive power, wherein the eleventh lens L11 is cemented with the twelfth lens L12 to form a cemented lens, and the fourteenth lens L14, the fifteenth lens L15 and the sixteenth lens L16 are cemented to form a triple cemented lens, which can effectively balance coma aberration, astigmatism and chromatic aberration of the front and rear lens groups, so that the sensitivity of the fitting tolerance of the front and rear lens groups is greatly reduced.
The first lens group G1 adopts multiple high-refractive-index lenses, and can effectively bend wide-angle incident light, so that when the wide-angle light enters the system diaphragm, the maximum deflection angle is smaller than 23 degrees.
The second lens group G2 is suitable for setting Abbe number of multiple lenses between 80 and 90, which is favorable for reducing dispersion.
The lens further includes a planar eighteenth lens L18, and the eighteenth lens L18 is close to the image side.
Referring now to Table one, numerical data for some embodiments, such as radius of curvature, thickness, refractive index, Abbe number, etc. of the lens are shown, where S1-S32 represent the mirror surface of the lens from the object side to the image side, and the numerical data are typically in "mm" units.
Table one:
fig. 2 is a diagram of spherical aberration on an axis according to an embodiment of the present disclosure, fig. 3 is a diagram of vertical axis chromatic aberration according to an embodiment of the present disclosure, and fig. 4 is a diagram of field curvature distortion according to an embodiment of the present disclosure. Fig. 5 is a light aberration diagram according to the embodiment of the disclosure, fig. 6 is a diffuse speckle diagram according to the embodiment of the disclosure, fig. 7 is an MTF diagram according to the embodiment of the disclosure, and fig. 8 is an MTF and field diagram according to the embodiment of the disclosure. According to the chart, the aberration of the lens disclosed by the invention is well corrected, a better imaging effect can be achieved in a full field of view, the lens can correct distortion of a wide-angle lens to realize small distortion on the premise of not using an aspheric surface, the shooting requirements of high resolution and high-pass light are met, the short-focus near focusing distance can be realized, low-distortion full field of view high definition can be considered, and the large-pass light aperture small volume can be realized.
The foregoing disclosure discloses only some embodiments of the invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept herein, and it is intended to cover all such modifications and variations as fall within the scope of the invention.
Claims (10)
1. A large wide-angle video lens with a focal length of 8mm, comprising in order from an object side to an image side: a first lens group (G1), an iris, and a second lens group (G2);
the first lens group (G1) has positive focal power and is fixed in position;
the second lens group (G2) has positive power and is movable in position in the optical axis direction;
the first lens group (G1) comprises a first negative lens group (G11) and a second negative lens group (G12), the first negative lens group (G11) comprises at least three negative lenses, and the second negative lens group (G12) comprises a negative cemented positive lens with negative power and a negative cemented positive lens with positive power;
the first lens group (G1) and the second lens group (G2) satisfy the following formula:
0.5<f1/f2<2；2<f12/f1<7；
wherein f1 represents a focal length value of the first lens group (G1), f2 represents a focal length value of the second lens group (G2), and f12 represents a focal length value of the second negative lens group (G12).
2. A large wide-angle video lens with focal length of 8mm, according to claim 1, characterized in that said second lens group (G2) comprises negative and positive cemented lens with negative power and triple cemented lens with positive power.
3. The large wide-angle video lens with focal length of 8mm as claimed in claim 1, wherein the first negative lens group (G11) comprises a first lens (L1), a second lens (L2), a third lens (L3) and a fourth lens (L4), and the second lens (L2), the third lens (L3) and the fourth lens (L4) all have negative power;
the mirror surface of each lens of the first negative lens group (G11) is curved toward the object side.
4. A large wide-angle video lens with focal length of 8mm, according to claim 1, characterized in that the refractive index of the fifth lens element (L5) and/or the sixth lens element (L6) of the first lens group (G1) is between 1.8 and 2.0.
5. A large wide-angle video lens with focal length of 8mm, according to claim 1, characterized in that the refractive index of the seventh lens element (L7) and/or the eighth lens element (L8) of the first lens group (G1) is between 1.9 and 2.0.
6. A large wide-angle video lens with focal length of 8mm, according to claim 1, characterized in that the refractive index of at least one lens in the cemented triplet of the second lens group (G2) is between 2.0 and 2.2.
7. A large wide-angle video lens with focal length of 8mm, according to claim 1, characterized in that said second lens group (G2) comprises at least three lenses with abbe number between 80 and 90.
8. A large wide-angle video lens with focal length of 8mm, according to claim 1, characterized in that said first lens group (G1) comprises at least three lenses with refractive index between 1.9 and 1.98.
9. The wide-angle video lens with a focal length of 8mm as claimed in claim 1, wherein the total length from the first mirror to the last mirror of the lens is between 70 mm to 77 mm, and the maximum aperture of the lens is between 50 mm to 55 mm.
10. A large wide-angle video lens with a focal length of 8mm as claimed in claim 1, wherein the back working distance of the lens is BFL, the focal length of the lens is f, and the following equation is satisfied: 2< BFL/f < 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010680371.4A CN111694135A (en) | 2020-07-15 | 2020-07-15 | Big wide angle video camera lens of focus 8mm |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010680371.4A CN111694135A (en) | 2020-07-15 | 2020-07-15 | Big wide angle video camera lens of focus 8mm |
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| CN111694135A true CN111694135A (en) | 2020-09-22 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113900239A (en) * | 2021-08-31 | 2022-01-07 | 福建福光股份有限公司 | Wide-angle large-area array starlight-level optical variable-pitch image detection lens |
| CN115032776A (en) * | 2022-06-01 | 2022-09-09 | 广东北创光电科技股份有限公司 | Long-focal-length flange video lens |
| CN115185072A (en) * | 2022-06-01 | 2022-10-14 | 广东北创光电科技股份有限公司 | Aspheric wide-angle long-flange video lens |
-
2020
- 2020-07-15 CN CN202010680371.4A patent/CN111694135A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113900239A (en) * | 2021-08-31 | 2022-01-07 | 福建福光股份有限公司 | Wide-angle large-area array starlight-level optical variable-pitch image detection lens |
| CN115032776A (en) * | 2022-06-01 | 2022-09-09 | 广东北创光电科技股份有限公司 | Long-focal-length flange video lens |
| CN115185072A (en) * | 2022-06-01 | 2022-10-14 | 广东北创光电科技股份有限公司 | Aspheric wide-angle long-flange video lens |
| CN115185072B (en) * | 2022-06-01 | 2024-03-12 | 广东北创光电科技股份有限公司 | Aspheric wide-angle long flange video lens |
| CN115032776B (en) * | 2022-06-01 | 2024-03-12 | 广东北创光电科技股份有限公司 | Long Jiao Changfa blue video lens |
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