CN116125644A - Optical module, zoom lens and endoscope - Google Patents
Optical module, zoom lens and endoscope Download PDFInfo
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- CN116125644A CN116125644A CN202211607209.5A CN202211607209A CN116125644A CN 116125644 A CN116125644 A CN 116125644A CN 202211607209 A CN202211607209 A CN 202211607209A CN 116125644 A CN116125644 A CN 116125644A
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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
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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
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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
- G02B15/16—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 with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
- G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
- G02B23/2407—Optical details
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Abstract
The invention relates to an optical module, a zoom lens and an endoscope, which sequentially comprise a first lens group, a second lens group, an aperture diaphragm and a third lens group from the object side to the image side, wherein the second lens group moves between the first lens group and the aperture diaphragm along the optical axis so as to enable the optical module to be switched between a short-focus state and a long-focus state; the focal length of the first lens group is f 1 The focal length of the third lens group is f 3 The short focal length of the optical module is f W The field angle of short focus is FOV W Length Jiao Jiaoju is f T The angle of field of view of the long focus is FOV T Then
And is also provided with
Compared with the prior art, the optical module has good imaging effect in the short-focus state and the long-focus state, field curvature and distortion are effectively inhibited, and aberration and coma are low.
Description
Technical Field
The present invention relates to the field of optical imaging, and in particular, to an optical module, a zoom lens, and an endoscope.
Background
Due to the high-speed development of intelligent medical treatment in recent years, the optical lens is increasingly applied in the medical field, particularly in the medical endoscope field, the pixel requirement of the optical imaging lens is higher and higher, and meanwhile, more enterprises are attracted to begin to put more researches on ultra-high definition, 4K and other endoscopes, and products with higher pixels and smaller sizes are expected to be developed. On the basis, the introduction of the zoom lens greatly improves the application field Jing Jianrong of the product. However, the aperture value of the traditional zoom lens is smaller, the imaging quality is generally difficult to meet the high-resolution application scene, and the imaging quality in the long-focus state and the short-focus state cannot be considered.
Disclosure of Invention
Accordingly, it is necessary to provide an optical module, a zoom lens, and an endoscope for solving the problem that both of the long-focus imaging and the short-focus imaging are difficult to achieve.
An optical module sequentially comprises a first lens group, a second lens group, an aperture diaphragm and a third lens group from an object side to an image side, wherein the second lens group moves along an optical axis between the first lens group and the aperture diaphragm so as to enable the optical module to be switched between a short-focus state and a long-focus state;
the focal length of the first lens group is f 1 The focal length of the third lens group is f 3 The short focal length of the optical module is f W The field angle of short focus is FOV W Length Jiao Jiaoju is f T The angle of field of view of the long focus is FOV T Then
And->
The first lens group comprises a first meniscus lens, a second meniscus lens and a third meniscus lens which are sequentially arranged from an object side to an image side, wherein the first meniscus lens and the third meniscus lens are positive focal power lenses, the second meniscus lens is a negative focal power lens, and the central curvature radius of the second meniscus lens on the image side is R 3 The center curvature radius of the third meniscus lens at the object side surface is R 4 Then
The focal length of the first meniscus lens is f 11 The optical module further comprises an imaging surface, the imaging surface is positioned at one side of the image side of the third lens group, and the total optical length of the optical module is TTL
The second lens group comprises a first biconcave lens, a second biconcave lens and a first biconvex lens which are sequentially arranged from an object side to an image side, the third lens group comprises a second biconvex lens, a third biconvex lens, a fourth meniscus lens and a third biconcave lens which are sequentially arranged from the object side to the image side, the first biconcave lens, the second biconvex lens and the third biconcave lens are negative focal power lenses, the first biconvex lens, the second biconvex lens, the third biconvex lens and the fourth meniscus lens are positive focal power lenses, the first meniscus lens and the second meniscus lens are glued, the second biconvex lens and the first biconvex lens are glued, and the focal length f of the third meniscus lens is f 13 The focal length f of the second biconcave lens is less than or equal to 46mm 22 Is more than or equal to-20.4 mm, and the focal length f of the second biconvex lens 31 ≤31.5mm。
The refractive index of the material of the first meniscus lens is Nd 11 The second meniscus is transparentThe refractive index of the mirror material is Nd 12 The refractive index of the material of the fourth meniscus lens is Nd 33 ，Nd 11 ≤1.81，Nd 12 ≤1.81，Nd 33 ≤1.85。
The optical module further comprises a fourth lens group, wherein the fourth lens group is positioned on one side, far away from the aperture diaphragm, of the third lens group, the fourth lens group comprises a fourth biconvex lens, and the fourth biconvex lens is a positive focal power lens.
The Abbe number of the material of the first meniscus lens is Vd 11 The Abbe number of the material of the second biconcave lens is Vd 22 The Abbe number of the material of the fourth biconvex lens is Vd 41 ，Vd 11 ≤65，Vd 22 ≤30，Vd 41 ≤69。
The optical module further comprises a light splitting device, wherein the light splitting device is positioned at one side of the fourth lens group far away from the third lens group.
In the invention, one surface of the second meniscus lens facing the image side is a convex surface, and one surface of the third meniscus lens facing the object side is a convex surface.
The fourth lens group is movably arranged on one side of the third lens group far away from the aperture diaphragm along the optical axis direction, when the second lens group moves along the optical axis to the aperture diaphragm, the fourth lens group moves along the optical axis to the third lens group, and when the second lens group moves along the optical axis to the first lens group, the fourth lens group moves along the optical axis to the direction far away from the third lens group.
A zoom lens includes an optical module.
An endoscope includes a zoom lens.
According to the invention, the short focal length and the short focal angle of view of the whole optical module are controlled by adjusting the focal length of the first lens group, so that the imaging quality of the optical module in a short focal state is improved, and the long Jiao Jiaoju and the long focal angle of view of the whole optical module are controlled by adjusting the focal length of the third lens group, so that the imaging quality of the optical module in a long focal state is improved. The imaging quality of the optical module can be effectively improved in the short-focus state and the long-focus state.
Compared with the prior art, the optical module has good imaging effect in the short-focus state and the long-focus state, field curvature and distortion are effectively inhibited, and aberration and coma are low.
Drawings
Fig. 1 is a schematic structural diagram of an optical module in a short focal state in embodiments 1 and 2 of the present invention;
fig. 2 is a schematic structural diagram of the optical module in the tele state in embodiments 1 and 2 of the present invention;
FIG. 3 is a graph showing the MTF of the optical module of example 1 in the visible light band at the low temperature and short focal length;
FIG. 4 is a graph showing the MTF of the optical module of example 1 in the visible light band at the normal temperature and in the long focal length state;
FIG. 5 is a graph showing curvature of field and distortion of a visible light band of an optical module according to embodiment 1 of the present invention in a short focal state;
FIG. 6 is a graph showing curvature of field and distortion of a visible light band of an optical module according to embodiment 1 of the present invention in a tele state;
FIG. 7 is a cross-sectional view of the optical module of embodiment 1 in the short focal length state in the visible light band;
FIG. 8 is a cross-sectional view of the optical module of embodiment 1 in the visible light band in the tele state;
FIG. 9 is a spot diagram of a visible light band of the optical module according to embodiment 1 of the present invention in a short focal state;
fig. 10 is a point chart of the visible light band of the optical module of embodiment 1 of the present invention in the short focal state.
Reference numerals:
g1, first lens group, L11, first meniscus lens, L12, second meniscus lens, L13, third meniscus lens;
g2, a second lens group, L21, a first biconcave lens, L22, a second biconcave lens, L23, and a first biconvex lens;
s, an aperture diaphragm;
g3, third lens group, L31, second biconvex lens, L32, third biconvex lens, L33, fourth meniscus lens, L34, third biconcave lens;
g4, fourth lens group, L41, fourth biconvex lens;
p, a light splitting device;
q, imaging plane.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.
Example 1:
referring to fig. 1 to 2, the present embodiment provides an optical module including, in order from an object side to an image side, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, a light splitting device P, a color filter, and an imaging plane Q.
The optical module has a long focal state and a short focal state, the first lens group G1, the aperture stop S, the third lens group G3, the beam splitting device P, the color filter and the imaging surface Q are kept stationary, the second lens group G2 can move along the optical axis between the first lens group G1 and the aperture stop S, the fourth lens group G4 can move along the optical axis between the third lens group G3 and the beam splitting device P, and the whole optical module is switched between the long focal state and the short focal state by the movement of the second lens group G2 and the fourth lens group G4.
In the present embodiment, when the second lens group G2 moves along the optical axis toward the first lens group G1 and the fourth lens group G4 moves along the optical axis toward the spectroscopic device P, the optical module gradually shifts from the tele state to the short-focus state, whereas when the second lens group G2 moves along the optical axis toward the aperture stop S and the fourth lens group G4 moves along the optical axis toward the third lens group G3, the optical module gradually shifts from the short-focus state to the tele state.
The short focal length of the optical module is f W The field angle of short focus is FOV W The focal length of the first lens group G1 is f 1 In order to improve the imaging quality and definition of the optical module in the short focal state, it is required to satisfy the following requirements
By adjusting the focal length of the first lens group G1 to f 1 For short Jiao Jiaoju f W And a short-focus field angle FOV W And optimizing to improve the imaging performance of the whole optical module in a short-focus state.
The length Jiao Jiaoju of the optical module is f T The angle of field of view of the long focus is FOV T The focal length of the third lens group G3 is f 3 In order to improve the imaging quality and definition of the optical module in the long focal state, the requirements are satisfied
By adjusting the focal length of the third lens group G3 to f 3 Length of Jiao Jiaoju f T And a tele angle FOV T Optimizing to improve imaging performance of the whole optical module in a long focus state, and reducing by an aperture diaphragm SLess influence of the first lens group G1 and the second lens group G2 on the imaging performance of the optical module in the long focal state, especially due to the focal length f of the first lens group G1 1 The change of (2) affects the imaging performance of the optical module in the tele state.
By focusing the focal length f of the first lens group G1 1 Focal length f of third lens group G3 3 The control is carried out, so that the optical performance parameters of the whole optical module can simultaneously meet the requirement of clear imaging no matter in a short-focus state or a long-focus state, the contradiction between the optical parameters which are required to be met by the optical module in the short-focus state and the optical parameters which are required to be met by the optical module in the long-focus state is reduced, and the imaging quality of the optical module in the short-focus state and the long-focus state is improved well.
Specifically, in the present embodiment, the first lens group G1 includes only the first meniscus lens L11, the second meniscus lens L12, and the third meniscus lens L13, which are disposed in order from the object side to the image side. Wherein the first meniscus lens L11 and the third meniscus lens L13 are positive focal power lenses, and the second meniscus lens L12 is a negative focal power lens. The first and second meniscus lenses L11 and L12 have convex surfaces on the image side, and the third meniscus lens L13 has a convex surface on the object side.
Preferably, the first meniscus lens L11 and the second meniscus lens L12 are glued to improve the final imaging quality of the optical module and reduce chromatic aberration.
The center curvature radius of the second meniscus lens L12 at the image side is R 3 The center curvature radius of the third meniscus lens L13 on the object side surface is R 4 In order to further improve the imaging quality of the optical module in the short focal state, it is required to satisfy the following requirements
The focal length of the first meniscus lens L11 is f 11 In order to improve the imaging quality of the optical module in the short focal state, the total optical length of the optical module is TTL
According to this relationship, the focal length f of the first meniscus lens L11 is made 11 The imaging performance impact of the optical module in the short focus state is in a relatively good range.
The number of the color filters and the imaging surfaces Q is two, so that one color filter and one imaging surface Q can be sequentially arranged on the two light emitting sides of the light splitting device P along the respective light emitting directions. In this embodiment, two optical paths are formed by the spectroscopic device P, and finally the total optical lengths of the two optical paths are equal, which is TTL.
In the present embodiment, the second lens group G2 includes only the first biconcave lens L21, the second biconcave lens L22, and the first biconvex lens L23, which are disposed in order from the object side to the image side. The relative positions of the first biconcave lens L21, the second biconcave lens L22, and the first biconvex lens L23 remain unchanged while the second lens group G2 is moved along the optical axis. Wherein the first biconcave lens L21 and the second biconcave lens L22 are negative power lenses, and the first biconvex lens L23 is a positive power lens.
In order to improve the final imaging quality of the optical module and reduce chromatic aberration, after the second biconcave lens L22 is glued with the first biconvex lens L23, the relative position stability between the second biconcave lens L22 and the first biconvex lens L23 can be improved, the internal stability of the second lens group G2 can be improved when the second lens group G2 moves, and the stability of the imaging quality of the optical module in the switching process between the long-focus state and the short-focus state is ensured.
In the present embodiment, the third lens group G3 includes only the second biconvex lens L31, the third biconvex lens L32, the fourth meniscus lens L33, and the third biconcave lens L34, which are disposed in order from the object side to the image side. The aperture stop S is always located between the first biconvex lens L23 and the second biconvex lens L31, and at the same time, the aperture stop S may be separated from the second biconvex lens L31 or may be fixed on the second biconvex lens L31, so that the aperture stop S is located between the first biconvex lens L23 and the second biconvex lens L31 in any manner.
Among them, the second biconvex lens L31, the third biconvex lens L32, and the fourth meniscus lens L33 are positive power lenses, and the third biconcave lens L34 is a negative power lens.
It can be appreciated that the focal length f of the first lens group G1 1 Subject to focal length f of third meniscus lens L13 13 The influence of the focal length f of the second lens group G2 2 Is subject to the focal length f of the second biconcave lens L22 22 The influence of the focal length f of the third lens group G3 3 Is subject to the focal length f of the second biconvex lens L31 31 While the adverse effect of the first lens group G1 and the second lens group G2 on the imaging quality of the optical module in the telephoto state is reduced by the aperture stop S, the adverse effect of the first lens group G1 and the second lens group G2 on the imaging quality of the optical module in the telephoto state is not completely eliminated, and thus the optical parameters of the first lens group G1 and the second lens group G2 need to be further optimized to further reduce the adverse effect of the imaging quality of the optical module in the telephoto state, and the optical parameters of the third lens group G3 need to be further optimized to further increase the effect of the third lens group G3 on the imaging quality of the optical module in the telephoto state, in this embodiment f 13 ≤46mm，f 22 ≥-20.4mm，f 31 ≤31.5mm。
The fourth lens group G4 in the present embodiment includes only the fourth biconvex lens L41, and the fourth biconvex lens L41 is a positive power lens.
In this embodiment, if the optical module is in the short focal state, the second lens group G2 and the fourth lens group G4 are required to be cooperatively controlled, so the optical parameters of the fourth lens group G4 are also important for the imaging quality of the optical module in the short focal state.
The refractive index of the material of the first meniscus lens L11 is Nd 11 The refractive index of the material of the second meniscus lens L12 is Nd 12 The refractive index of the material of the fourth meniscus lens L33 is Nd 33 In order to further improve the imaging quality of the optical module in the short-focus state, nd 11 ≤1.81，Nd 12 ≤1.81，Nd 33 Less than or equal to 1.85. By Nd to Nd 11 And Nd 12 Is controlled to reduce the optical mode induced by the resulting change in the optical parameter of the first lens group G1Adverse effects of imaging quality in the tele regime for the group.
If the optical parameters of the first lens group G1, the second lens group G2 and the fourth lens group G4 are further optimized, the imaging quality of the optical module in the long-focus state and the short-focus state can be improved at the same time. To achieve the object, in the present embodiment, the Abbe number of the first meniscus lens L11 is Vd 11 The Abbe number of the material of the second biconcave lens L22 is Vd 22 The Abbe number of the material of the fourth biconvex lens L41 is Vd 41 ，Vd 11 ≤65，Vd 22 ≤30，Vd 41 ≤69。
In this embodiment, the optical parameters of each component of the whole optical module are shown in table 1.
TABLE 1
It should be noted that, in the schematic view of the optical module shown in fig. 1, the mirror numbers in table 1 are the numbers of the lenses from left to right; center thickness T c Representing the spacing between the mirror and its adjacent mirror near the image side.
Wherein the variable thickness data is as in parameter table 2.
TABLE 2
| Focal length | D5 | D10 | D18 | D20 |
| 19.39mm | 0.39 | 9.17 | 3.32 | 5.77 |
| 35.00mm | 9.47 | 0.1 | 1.40 | 7.68 |
The optical module provided by the embodiment has the following optical technical indexes:
the total optical length TTL is less than or equal to 59.4mm;
focal length f:19.39 (W) mm-35 (T) mm;
field angle FOV:26.4 ° (W) to 14.31 ° (T);
optical distortion: -3.1% (W) to 0.25% (T);
the aperture FNO is less than or equal to 4.5;
image plane size: 1/1.8 ";
note that: w represents short focus and T represents long focus.
In the present embodiment, the focal length of the first lens group G1 is f 1 The focal length of the third lens group G3 is f 3 The method comprises the steps of carrying out a first treatment on the surface of the The short focal length of the optical module is f W The field angle of short focus is FOV W The method comprises the steps of carrying out a first treatment on the surface of the The length Jiao Jiaoju of the optical module is f T The angle of field of view of the long focus is FOV T Satisfies the following conditions
The central radius of curvature R of the second meniscus lens L12 at the image side 3 And a center radius of curvature R of the third meniscus lens L13 on the object side 4 Satisfy the following requirements
Focal length f of first meniscus lens L11 11 And the optical total length TTL of the optical module meets +.>
Focal length f of third meniscus lens L13 13 The focal length f of the second biconcave lens L22 = 45.35mm 22 -20.35mm, focal length f of second biconvex lens L31 31 =15.60 mm; abbe number Vd of material of first meniscus lens L11 11 Material abbe number Vd of the second biconcave lens L22 =46.56 22 Material abbe number Vd of fourth biconvex lens L41 =17.98 41 = 68.62; refractive index Nd of material of first meniscus lens L11 11 Material refractive index Nd of second meniscus lens L12 =1.80 12 Material refractive index Nd of fourth meniscus lens L33=1.80 33 ＝1.78。
The optical transfer function (MTF) is a more accurate, visual and common way to evaluate the imaging quality of an imaging system, and the higher and smoother the curve, the better the imaging quality of the system, and the better correction of various aberrations (such as spherical aberration, coma, astigmatism, field curvature, axial chromatic aberration, vertical chromatic aberration and the like) is performed. As shown in fig. 3, the MTF curve of the optical module of the present embodiment in the visible light band at the low temperature and the short focal state is shown. As shown in fig. 4, the MTF curve of the optical module of the present embodiment in the visible light band at normal temperature and in the long focal state is shown. The optical module of the embodiment is smoother in both the long-focus state and the short-focus state, and the average value of the MTF is above 0.4 in the full view field (half image height 4.4 mm), so that the imaging quality is higher.
The field Qu Youchen "curvature of field" is such that when the lens is in curvature of field, the intersection of the entire beam does not coincide with the ideal image point, and although a clear image point is obtained at each particular point, the entire image plane is a curved surface. T represents the meridian curvature and S represents the sagittal curvature. The field curvature curve shows the distance of the current focal plane or image plane to the paraxial focal plane as a function of the field coordinates, and the meridian field curvature data is the distance measured along the Z-axis from the currently determined focal plane to the paraxial focal plane and is measured on the meridian (YZ-plane). The sagittal field curvature data measures the distance measured in a plane perpendicular to the meridian plane, the base line in the diagram being on the optical axis, the top of the curve representing the maximum field of view (angle or height), and no units being placed on the longitudinal axis, since the curve is always normalized by the maximum radial field of view.
Lens distortion is a generic term for the inherent perspective distortion of an optical lens, i.e. distortion due to perspective, which is very detrimental to the imaging quality of a photograph, after all for the purpose of reproduction, not exaggeration, but cannot be eliminated and only improved because it is an inherent characteristic of the lens (convex lens converging rays, concave lens diverging rays).
Fig. 5 is a graph of curvature of field and distortion of a visible light band of the optical module of the present embodiment in a short focal state, and fig. 6 is a graph of curvature of field and distortion of a visible light band of the optical module of the present embodiment in a long focal state, both of which are designed with reference to a plurality of wavelengths (0.435 μm, 0.486 μm, 0.546 μm, 0.587 μm, and 0.656 μm). As can be seen from fig. 5 and 6, the curvature of field of the optical module in the embodiment is controlled within ±0.03mm in the short focal state, the distortion is controlled within-3.1%, the curvature of field in the long focal state is controlled within ±0.05mmm, the distortion is within +0.25%, and both the long focal state and the short focal state are effectively suppressed. Meanwhile, the distortion setting in the short-focus state and the long-focus state can also balance the focal length, the field angle and the size of the corresponding camera target surface, so that the distortion can be corrected through later image processing.
Referring to fig. 7-8, fig. 7 is a transverse light fan diagram of the visible light band of the optical module of the present embodiment in the short focal state, and fig. 8 is a transverse light fan diagram of the visible light band of the optical module of the present embodiment in the long focal state, it can be seen that the curve is relatively flat in both the short focal state and the long focal state, which indicates that the spherical aberration and chromatic dispersion control of the optical module are relatively good.
Referring to fig. 9-10, fig. 9 is a point diagram of a visible light band of the optical module of the present embodiment in a short focal state, and fig. 10 is a point diagram of a visible light band of the optical module of the present embodiment in a long focal state, where the spot radius is smaller, the light spot is more concentrated, and the corresponding aberration and coma are smaller, regardless of the short focal state or the long focal state.
The optical module of the embodiment has the characteristics of large target surface, large aperture and high resolution and is low in cost.
Example 2:
the difference between this embodiment and embodiment 1 is that the parameters of each lens in the optical module are changed, see table 3.
TABLE 3 Table 3
It should be noted that, in the schematic view of the optical module shown in fig. 1, the mirror numbers in table 3 are the numbers of the lenses from left to right; center thickness T c Representing the spacing between the mirror and its adjacent mirror near the image side.
Wherein the variable thickness data is as in parameter table 4.
TABLE 4 Table 4
| Focal length | D5 | D10 | D18 | D20 |
| 19.2mm | 0.33 | 8.12 | 1.11 | 7.82 |
| 35.0mm | 8.36 | 0.10 | 8.83 | 0.10 |
The optical module provided by the embodiment has the following optical technical indexes:
the total optical length TTL is less than or equal to 60mm;
focal length f:19.2 (W) mm-35.0 (T) mm;
field angle FOV:26.98 ° (W) to 14.40 ° (T);
optical distortion: -4.5% (W) to 0.47% (T);
the aperture FNO is less than or equal to 3.58;
image plane size: 1/1.8 ";
note that: w represents short focus and T represents long focus.
In the present embodiment, the focal length of the first lens group G1 is f 1 The focal length of the third lens group G3 is f 3 The method comprises the steps of carrying out a first treatment on the surface of the The short focal length of the optical module is f W The field angle of short focus is FOV W The method comprises the steps of carrying out a first treatment on the surface of the The length Jiao Jiaoju of the optical module is f T The angle of field of view of the long focus is FOV T Satisfies the following conditions
The central radius of curvature R of the second meniscus lens L12 at the image side 3 And a center radius of curvature R of the third meniscus lens L13 on the object side 4 Satisfy->
Focal length f of first meniscus lens L11 11 And opticsThe optical total length TTL of the module satisfies +.>
Focal length f of third meniscus lens L13 13 =31.25 mm, focal length f of second biconcave lens L22 22 = -14.39mm, focal length f of second biconvex lens L31 31 = 31.41mm; abbe number Vd of material of first meniscus lens L11 11 64.21 Abbe number Vd of the second biconcave lens L22 22 Material abbe number Vd of fourth biconvex lens L41 =29.13 41 = 63.40; refractive index Nd of material of first meniscus lens L11 11 Material refractive index Nd of second meniscus lens L12 =1.51 12 Material refractive index Nd of fourth meniscus lens L33=1.76 33 ＝1.84。
Examples 1 and 2 satisfy the relationships shown in table 5.
TABLE 5
Example 3:
the present embodiment provides a zoom lens including the optical module of embodiment 1. The zoom lens of the present embodiment can meet the high resolution requirement of a 1/1.8 inch sensor (CCD/CMOS) camera.
Example 4:
the present embodiment provides an endoscope including the zoom lens in embodiment 2.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (12)
1. An optical module, characterized by comprising a first lens group (G1), a second lens group (G2), an aperture stop (S) and a third lens group (G3) in order from an object side to an image side, the second lens group (G2) moving along an optical axis between the first lens group (G1) and the aperture stop (S) to switch the optical module between a short-focus state and a long-focus state;
the focal length of the first lens group (G1) is f 1 The focal length of the third lens group (G3) is f 3 The short focal length of the optical module is f W The field angle of short focus is FOV W Length Jiao Jiaoju is f T The angle of field of view of the long focus is FOV T Then
And->
2. The optical module according to claim 1, wherein the first lens group (G1) includes a first meniscus lens (L11), a second meniscus lens (L12), and a third meniscus lens (L13) disposed in order from the object side to the image side, the first meniscus lens (L11) and the third meniscus lens (L13) being positive power lenses, the second meniscus lens (L12) being negative power lenses, a center radius of curvature of the second meniscus lens (L12) on the image side being R 3 The center curvature radius of the third meniscus lens (L13) at the object side is R 4 Then
3. An optical module according to claim 2, wherein the focal length of the first meniscus lens (L11) is f 11 The optical module further comprises an imaging surface (Q), wherein the imaging surface (Q) is positioned at one side of the image side of the third lens group (G3), and the total optical length of the optical module is TTL
4. The optical module according to claim 2, wherein the second lens group (G2) includes a first biconcave lens (L21), a second biconcave lens (L22), and a first biconvex lens (L23) disposed in order from the object side to the image side, the third lens group (G3) includes a second biconvex lens (L31), a third biconvex lens (L32), a fourth meniscus lens (L33), and a third biconcave lens (L34) disposed in order from the object side to the image side, the first biconcave lens (L21), the second biconcave lens (L22), and the third biconvex lens (L34) are negative power lenses, the first biconvex lens (L23), the second biconvex lens (L31), the third biconvex lens (L32), and the fourth meniscus lens (L33) are positive power lenses, the first meniscus lens (L11) and the second meniscus lens (L12) are cemented, the second biconvex lens (L22) and the third biconvex lens (L13) are cemented with positive power lenses (L23) 13 A focal length f of the second biconcave lens (L22) of 46mm or less 22 Not less than-20.4 mm, the focal length f of the second biconvex lens (L31) 31 ≤31.5mm。
5. An optical module according to claim 4, wherein the refractive index of the material of the first meniscus lens (L11) is Nd 11 The refractive index of the material of the second meniscus lens (L12) is Nd 12 The material refractive index of the fourth meniscus lens (L33) is Nd 33 ，Nd 11 ≤1.81，Nd 12 ≤1.81，Nd 33 ≤1.85。
6. The optical module according to claim 4, further comprising a fourth lens group (G4), the fourth lens group (G4) being located on a side of the third lens group (G3) remote from the aperture stop (S), the fourth lens group (G4) comprising a fourth biconvex lens (L41), the fourth biconvex lens (L41) being a positive power lens.
7. An optical module according to claim 6, wherein the abbe number of the material of the first meniscus lens (L11) is Vd 11 The Abbe number of the material of the second biconcave lens (L22) is Vd 22 The fourth biconvex lens (L41) has a material Abbe number Vd 41 ，Vd 11 ≤65，Vd 22 ≤30，Vd 41 ≤69。
8. An optical module according to claim 6, characterized in that the optical module further comprises a light splitting device (P) located at a side of the fourth lens group (G4) remote from the third lens group (G3).
9. The optical module according to claim 6, wherein a surface of the second meniscus lens (L12) facing the image side is convex, and a surface of the third meniscus lens (L13) facing the object side is convex.
10. An optical module according to claim 6, wherein the fourth lens group (G4) is movably disposed in an optical axis direction on a side of the third lens group (G3) away from the aperture stop (S), the fourth lens group (G4) being moved in the optical axis direction toward the third lens group (G3) when the second lens group (G2) is moved in the optical axis direction toward the aperture stop (S), the fourth lens group (G4) being moved in the optical axis direction away from the third lens group (G3) when the second lens group (G2) is moved in the optical axis direction toward the first lens group (G1).
11. A zoom lens comprising an optical module according to any one of claims 1 to 10.
12. An endoscope comprising the zoom lens according to claim 11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211607209.5A CN116125644A (en) | 2022-12-14 | 2022-12-14 | Optical module, zoom lens and endoscope |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211607209.5A CN116125644A (en) | 2022-12-14 | 2022-12-14 | Optical module, zoom lens and endoscope |
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| Publication Number | Publication Date |
|---|---|
| CN116125644A true CN116125644A (en) | 2023-05-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211607209.5A Pending CN116125644A (en) | 2022-12-14 | 2022-12-14 | Optical module, zoom lens and endoscope |
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| Country | Link |
|---|---|
| CN (1) | CN116125644A (en) |
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2022
- 2022-12-14 CN CN202211607209.5A patent/CN116125644A/en active Pending
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