CN112305733A - Two-gear zooming large-target-surface low-light-level optical system with variable aperture diaphragm position - Google Patents
Two-gear zooming large-target-surface low-light-level optical system with variable aperture diaphragm position Download PDFInfo
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- CN112305733A CN112305733A CN202011259945.7A CN202011259945A CN112305733A CN 112305733 A CN112305733 A CN 112305733A CN 202011259945 A CN202011259945 A CN 202011259945A CN 112305733 A CN112305733 A CN 112305733A
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- 230000003287 optical effect Effects 0.000 title claims abstract description 53
- 238000003384 imaging method Methods 0.000 claims abstract description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims description 12
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 12
- 230000005499 meniscus Effects 0.000 claims description 12
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 4
- 229910052731 fluorine Inorganic materials 0.000 claims description 4
- 239000011737 fluorine Substances 0.000 claims description 4
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 claims description 3
- 239000010428 baryte Substances 0.000 claims description 3
- 229910052601 baryte Inorganic materials 0.000 claims description 3
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 3
- 239000005357 flat glass Substances 0.000 claims description 3
- 239000010436 fluorite Substances 0.000 claims description 3
- 125000001153 fluoro group Chemical group F* 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 7
- 238000005286 illumination Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005622 photoelectricity Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
- G02B15/1431—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being positive
- G02B15/143105—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being positive arranged +-+
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/14—Optical objectives specially designed for the purposes specified below for use with infrared or ultraviolet radiation
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B9/00—Exposure-making shutters; Diaphragms
- G03B9/02—Diaphragms
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- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Health & Medical Sciences (AREA)
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Abstract
The invention discloses a two-gear zooming large-target-surface low-light-level optical system at a variable aperture diaphragm position, which sequentially comprises a front fixed group with positive diopter, a zooming group with negative diopter and a rear fixed group with positive diopter from an object space to an image space, wherein the zooming group is used for zooming and focusing simultaneously; the optical system also comprises a mechanical iris diaphragm which is positioned on the rear surface of the last lens of the front fixed group; when the zooming group is far away from the front fixed group, the aperture of the mechanical iris diaphragm is reduced, the optical system is in a long-focus position, when the zooming group is close to the front fixed group, the aperture of the mechanical iris diaphragm is increased, the optical system is in a short-focus position, and the formed virtual aperture diaphragm is positioned on the front surface of the first lens of the front fixed group. The invention has good imaging quality.
Description
Technical Field
The invention relates to the technical field of optics, in particular to a two-gear zooming large-target-surface low-light-level optical system with a variable aperture diaphragm.
Background
The low-light-level photoelectric equipment can also obtain a target image under the condition of low illumination, has higher resolution and definition compared with an infrared band, is widely applied to the fields of night observation, aiming, driving, navigation, guidance and the like, can respond to the illumination intensity of e-4Lux along with the progress of a solid-state CMOS image sensor in recent years, and is gradually applied to handheld photoelectric equipment, helmets and the like.
The zoom optical system can simultaneously have the characteristics of large visual field, high resolution and the like, and is also gradually applied to a low-light-level optical system, but the aperture diaphragm of the visible light zoom optical system is generally positioned in a rear fixed group, the positions of the apertures diaphragms with different focal positions are unchanged, and the zoom optical system is directly applied to the low-light-level optical system with a small F # and a large target surface, so that the aperture of the optical system is sharply increased, the optical length is longer, the off-axis visual field is large in vignetting, and the zoom optical system is not suitable for individual equipment with higher requirements on volume and weight, such as helmets, handheld photoelectricity.
Disclosure of Invention
The invention aims to provide a variable-aperture diaphragm position two-gear zooming large-target-surface low-light-level optical system, wherein the aperture diaphragm position is arranged at different positions of a front fixed group at different focal positions, so that the problems of large lens aperture, long optical system length, large off-axis vignetting and the like caused by the unchangeable aperture diaphragm position of the large-target-surface zooming optical system are solved, and the design of the large-target-surface low-light-level zooming optical system is realized in a smaller space.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the two-gear zooming large-target-surface micro-optical system at the position of the aperture-variable diaphragm comprises a front fixed group with positive diopter, a zooming group with negative diopter and a rear fixed group with positive diopter in sequence from an object space to an image space, wherein the zooming group is used for zooming and focusing simultaneously;
the optical system also comprises an aperture diaphragm, the position of the aperture diaphragm changes along with the change of the focal length, when the zoom group is far away from the front fixed group, the optical system is at a long-focus position, and the aperture diaphragm is positioned on the rear surface of the last lens of the front fixed group; when the zoom group is close to the front fixed group, the optical system is in a short-focus position, and the aperture diaphragm is positioned on the front surface of the first lens of the front fixed group.
According to the technical scheme, when the optical system is at the long-focus position, the F # is 3; when the optical system is in the short focus position, F # is 1.4.
The technical scheme is as follows:
the front fixing group comprises a first cemented objective lens and a second cemented objective lens; the first cemented objective lens comprises a meniscus light crown lens with negative focal power and a fluorite biconvex lens with positive focal power; the second cemented objective comprises a double-convex fluorine crown lens with positive focal power and a lanthanum flint double-concave lens with negative focal power;
the zoom group comprises a zoom lens I, a zoom lens II and a cemented objective lens III; the zoom lens I is a biconvex lanthanum flint lens with positive focal power; the second zoom lens is a meniscus lanthanum flint lens with negative focal power; the third cemented objective comprises a meniscus fluorine crown lens with positive focal power and a biconcave flint lens with negative focal power;
the rear fixing group comprises a first rear fixing mirror, a filter and a second rear fixing mirror; the first rear fixed mirror is a biconvex barite flint lens with positive focal power; the second rear fixed mirror is a meniscus lanthanum flint lens with negative focal power; the filter is flat glass.
According to the technical scheme, the working waveband of the optical system is 450-950 nm, the focal length is 80mm/120mm, and the total optical length is 123.6 mm.
According to the technical scheme, the zoom group is further used for moving back and forth along the optical axis to compensate the temperature and the drift of the image surface of the long-wave infrared optical system in the short-distance imaging.
In connection with the technical scheme, the optical system is applied to a solid-state low-light-level CCD with the resolution of 1280 multiplied by 1024 and the pixel size of 12 mu m multiplied by 12 mu m.
The invention has the following beneficial effects: according to the two-gear zooming large-target-surface low-light-level optical system with the variable-aperture diaphragm, the aperture diaphragm is arranged at different positions of the front fixing group at different focal positions, so that the problems of large lens aperture, long optical system length, large off-axis vignetting and the like caused by the fact that the aperture diaphragm of the large-target-surface zooming optical system is not variable are solved, and the design of the large-target-surface low-light-level zooming optical system is realized in a smaller space.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a schematic structural diagram of a two-stage variable-aperture large-target-surface micro-optic system at a short-focus position according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a two-stage variable-focus large-target-surface low-light-level optical system at a variable-aperture diaphragm position according to an embodiment of the present invention at a telephoto position;
FIG. 3 is a two-dimensional diagram of a two-step variable-aperture stop position large-target-surface micro-optic system in a short-focus position according to an embodiment of the present invention;
FIG. 4 is a two-dimensional diagram of an optical system when a two-step variable-aperture diaphragm position large-target-surface micro-optic system is located at a telephoto position according to an embodiment of the present invention;
FIG. 5 is a diagram of a transfer function of an optical system in a short focus position according to an embodiment of the present invention;
FIG. 6 is a diagram of a transfer function of an optical system at a tele position according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1 and fig. 2, the two-step variable-focus large-target-surface micro-optic system with variable aperture stop position according to the embodiment of the present invention includes, in order from the object side to the image side, a front fixed group 1 with positive diopter, a zoom group 2 with negative diopter, and a rear fixed group 3 with positive diopter. The front fixed group 1 is used for converging object space light rays, the aperture diaphragm 4 is a virtual optical diaphragm, the position of the aperture diaphragm changes along with the change of focal length, and a mechanical variable diaphragm is arranged on the rear surface of the last lens of the front fixed group. As shown in fig. 2, when the magnification-varying group 2 is far from the front fixed group 1, the optical system is in the telephoto position, the mechanical iris aperture is reduced, and the beam aperture is limited, where the position of the mechanical iris is the position of the virtual aperture stop 4, and F # is 3; as shown in fig. 1, when the variable power group 2 is close to the front fixed group 1, the optical system is in a short focus position, the aperture of the mechanical iris diaphragm becomes large, and the aperture of the beam is no longer limited, and the surface for limiting the aperture of the beam is the front surface of the first lens of the front fixed group, i.e. the virtual aperture stop 4 is located on the front surface of the first lens of the front fixed group, and F # is 1.4.
The working waveband of the optical system of the embodiment of the invention is 450 nm-950 nm, the focal length is 80mm/120mm, the total optical length is 123.6mm, and the optical system is suitable for a solid low-light-level CCD with the resolution of 1280 multiplied by 1024 and the pixel size of 12 multiplied by 12 mu m.
Specifically, the front fixed group 1 is composed of a cemented objective lens one 11 and a cemented objective lens two 12. The first cemented objective lens consists of a meniscus light crown lens with negative focal power and a fluorite biconvex lens with positive focal power; the second cemented objective consists of a double-convex fluorine crown lens with positive focal power and a lanthanum flint double-concave lens with negative focal power;
the variable-power group 2 consists of a first variable-power lens 21, a second variable-power lens 22 and a third cemented objective lens 23. The first zoom lens 21 is a biconvex lanthanum flint lens with positive focal power; the second zoom lens 22 is a meniscus lanthanum flint lens with negative focal power; the third cemented objective 23 consists of a meniscus fluoro crown lens with positive focal power and a biconcave heavy flint lens with negative focal power; the central interval of the back surfaces of the second cemented objective 12 of the zoom group 2 and the front fixed group 1 ranges from 33.7mm to 4.2 mm.
The rear fixed group 3 is composed of a first rear fixed mirror 31, a filter 32 and a second rear fixed mirror 33. The first rear fixed mirror 31 is a biconvex barite flint lens with positive focal power; the second rear fixed mirror 32 is a meniscus lanthanum flint lens with negative power. The filter 32 is a flat glass, and can be switched or selected according to actual use conditions.
In the preferred embodiment of the present invention, the specific design parameters of the optical system are shown in table 1.
TABLE 1 optical system design parameter Table
TABLE 2 transfer function values
In table 1, radius of curvature refers to the radius of curvature of each lens surface, thickness or spacing refers to the lens thickness or distance between adjacent lens surfaces, material is the lens material, and air refers to the medium between two lenses being air.
Fig. 3-6 are a two-dimensional diagram and a transfer function curve of a two-step zoom large-target-surface micro-optic system at a long-focus position and a short-focus position, respectively, of a variable-aperture diaphragm position according to an embodiment of the present invention.
It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.
Claims (6)
1. A two-gear zooming large-target-surface micro-optical system with a variable aperture diaphragm position is characterized by sequentially comprising a front fixed group (1) with positive diopter, a zooming group (2) with negative diopter and a rear fixed group (3) with positive diopter from an object space to an image space, wherein the zooming group (2) is used for zooming and focusing simultaneously;
the optical system also comprises a mechanical iris diaphragm which is positioned on the rear surface of the last lens of the front fixed group (1); when the zoom group (2) is far away from the front fixed group (1), the aperture of the mechanical iris diaphragm is reduced, the optical system is in a long-focus position, when the zoom group is close to the front fixed group (1), the aperture of the mechanical iris diaphragm is increased, the optical system is in a short-focus position, and the formed virtual aperture diaphragm is positioned on the front surface of the first lens of the front fixed group (1).
2. A two-stage variable focal length large target surface micro-optic system as claimed in claim 1, wherein F # is 3 in the telephoto position and 1.4 in the short focus position.
3. A variable aperture stop position two-stage zoom large-target-surface micro-optic system as claimed in claim 1, wherein:
the front fixing group (1) comprises a first cemented objective lens (11) and a second cemented objective lens (12); the first cemented objective lens comprises a meniscus light crown lens with negative focal power and a fluorite biconvex lens with positive focal power; the second cemented objective comprises a double-convex fluorine crown lens with positive focal power and a lanthanum flint double-concave lens with negative focal power;
the zoom group (2) comprises a zoom lens I (21), a zoom lens II (22) and a cemented objective lens III (23); the zoom lens I (21) is a biconvex lanthanum flint lens with positive focal power; the second zoom lens (22) is a meniscus lanthanum flint lens with negative focal power; the third cemented objective (23) comprises a meniscus fluoro crown lens with positive power and a biconcave flint lens with negative power;
the rear fixing group (3) comprises a first rear fixing mirror (31), a filter (32) and a second rear fixing mirror (33); the first rear fixed mirror (31) is a biconvex barite flint lens with positive focal power; the second rear fixed mirror (33) is a meniscus lanthanum flint lens with negative focal power; the filter (32) is a plate glass.
4. A two-stage variable-aperture diaphragm position large-target-surface micro-optical system as claimed in claim 1, wherein the working band of the optical system is 450nm to 950nm, the focal length is 80mm/120mm, and the total optical length is 123.6 mm.
5. The two-stage zooming large-target-surface micro-optical system with the variable-aperture diaphragm position as set forth in claim 1, characterized in that the zoom group (3) is further used for moving back and forth along the optical axis to compensate for temperature and drift of the image surface of the long-wave infrared optical system in short-distance imaging.
6. A two-stage variable-aperture diaphragm position large-target-surface micro-optical system as claimed in claim 1, characterized in that the optical system is applied to a solid-state micro-CCD with a resolution of 1280 x 1024 and a pixel size of 12 μm x 12 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011259945.7A CN112305733A (en) | 2020-11-12 | 2020-11-12 | Two-gear zooming large-target-surface low-light-level optical system with variable aperture diaphragm position |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011259945.7A CN112305733A (en) | 2020-11-12 | 2020-11-12 | Two-gear zooming large-target-surface low-light-level optical system with variable aperture diaphragm position |
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| Publication Number | Publication Date |
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| CN112305733A true CN112305733A (en) | 2021-02-02 |
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|---|---|---|---|
| CN202011259945.7A Pending CN112305733A (en) | 2020-11-12 | 2020-11-12 | Two-gear zooming large-target-surface low-light-level optical system with variable aperture diaphragm position |
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| CN (1) | CN112305733A (en) |
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- 2020-11-12 CN CN202011259945.7A patent/CN112305733A/en active Pending
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