CN109425963B - Optical lens - Google Patents
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- CN109425963B CN109425963B CN201710774439.3A CN201710774439A CN109425963B CN 109425963 B CN109425963 B CN 109425963B CN 201710774439 A CN201710774439 A CN 201710774439A CN 109425963 B CN109425963 B CN 109425963B
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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
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
- G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
- G02B13/0045—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
Abstract
The invention provides an optical lens. The optical lens includes, in order from an object side to an image side: a first lens having a positive refractive power; the second lens is a meniscus lens with negative focal power, and the object side surface of the second lens is a convex surface and the image side surface of the second lens is a concave surface; a third lens having a negative focal power; a fourth lens having a positive refractive power; and a fifth lens element having a meniscus shape with a positive refractive power, the object-side surface of the fifth lens element being convex and the image-side surface of the fifth lens element being concave. The optical lens provided by the invention can realize small FNO, small distortion, low cost and high thermal stability while keeping the miniaturization of the lens by optimally setting the shape of each lens and reasonably distributing the focal power of each lens.
Description
Technical Field
The present invention relates to the field of optical lenses, and more particularly to an optical lens capable of achieving at least small FNO, small distortion, low cost, and high thermal stability while ensuring miniaturization.
Background
For some lenses, it is desirable to collect as much light as possible so that the image sensing chip behind the lens can receive most of the energy of the incident light. Therefore, the lens requires a small FNO, so that the lens can receive more light, and the requirement for distortion is high.
Here, FNO refers to the ratio of the focal length to the clear aperture, reflecting the amount of light passing through the lens. The smaller the FNO value, the larger the aperture, and the larger the lens light flux.
However, for a lens with a small Fno (about 1.2), it is directly difficult to achieve the small dispersion as a normal imaging lens, and for such a lens with a small Fno, the diffuse spot is generally controlled in a half range of the pixel size, for example: for a lens with a pixel size of 100um, the diffuse spot should be controlled within 50 um. In actual manufacturing, various tolerances are inevitably introduced, so that dispersion is deteriorated, the received energy of the pixel is weakened, and the performance of the lens is reduced; when the ambient temperature changes, the lens deforms, and the best image plane deviates from the chip position, which also causes the performance of the lens at the receiving end to be poor.
Therefore, in order to meet the performance requirements of the optical lens at present, the optical lens needs to be optimally designed to meet the requirements of miniaturization, small FNO, small distortion, low cost, high thermal stability and the like.
Disclosure of Invention
The present invention is directed to addressing the above-discussed deficiencies and drawbacks of the prior art and providing a novel and improved optical lens that enables simultaneous or partial miniaturization, small FNO, small distortion, low cost, and high thermal stability of the lens.
The present invention has an advantage of providing an optical lens that can realize small FNO, small distortion, low cost, and high thermal stability while keeping the lens compact by optimally setting the shapes of respective lenses and reasonably distributing the focal powers of the respective lenses.
The invention has the advantages that the second lens and the fifth lens are meniscus lenses which are convex to the object side, so that the aberration and the distortion of an optical system can be reduced.
The optical lens has the advantages that the second lens and the fifth lens are in the shapes close to concentric circles, so that optical aberration can be reduced, and the size of a dispersed spot can be reduced.
The invention has the advantage of providing the optical lens, and the high thermal stability of the optical lens can be realized by adjusting the focal length ratio of the second lens and the fifth lens.
The invention has the advantage of providing the optical lens, and the second lens and the fifth lens are plastic aspheric lenses, so that the optical lens can be realized at low cost.
The invention has the advantages that the first lens is the meniscus lens which is convex to the object, the caliber of the second lens and the distance between the first lens and the second lens can be effectively reduced, and the miniaturization of the optical lens is facilitated.
The invention has the advantages that the optical lens is provided, and the refractive index of the first lens is more than or equal to 1.66, so that the thickness of the first lens is reduced, and the miniaturization of the optical lens is realized.
The invention has the advantage of providing an optical lens, wherein a cemented lens with a front negative film is formed by the third lens and the fourth lens, which is helpful for further reducing system aberration.
The invention has the advantages that the positive and negative aberration introduced by the optical system before can be effectively reduced by adjusting the focal length ratio of the third lens and the fourth lens to enable the focal lengths of the third lens and the fourth lens to be close to each other, so that the speckle is reduced.
The invention has the advantage of providing the optical lens, which is beneficial to reducing the distance from the image side surface of the fifth lens to the imaging surface through the refractive index of the fifth lens being more than or equal to 1.58 so as to realize the miniaturization of the optical lens.
According to an aspect of the present invention, there is provided an optical lens including, in order from an object side to an image side: a first lens having a positive refractive power; the second lens is a meniscus lens with negative focal power, and the object side surface of the second lens is a convex surface and the image side surface of the second lens is a concave surface; a third lens having a negative focal power; a fourth lens having a positive refractive power; and a fifth lens element having a meniscus shape with a positive refractive power, the object-side surface of the fifth lens element being convex and the image-side surface of the fifth lens element being concave.
In the above optical lens system, the first lens element is a meniscus lens element, and has a convex object-side surface and a concave image-side surface.
In the above optical lens system, the third lens element is a meniscus lens element, and has a concave object-side surface and a convex image-side surface; and the fourth lens is a meniscus lens, and the object side surface of the fourth lens is a concave surface and the image side surface of the fourth lens is a convex surface.
In the optical lens assembly, the third lens element is a biconcave lens element, and has a concave object-side surface and a concave image-side surface; and the fourth lens is a biconvex lens, and the object side surface of the fourth lens is a convex surface and the image side surface of the fourth lens is a convex surface.
In the above optical lens, the third lens and the fourth lens are cemented lenses.
In the above optical lens, the second lens and the fifth lens are aspherical lenses.
In the above optical lens, the first lens satisfies the following conditional expression (1):
Nd1≥1.66 (1)
wherein Nd1 is a refractive index of the first lens.
In the above optical lens, the second lens satisfies the following conditional expression (2):
0.6≤(r3-d3)/r4≤1 (2)
where r3 is the radius of curvature of the object-side surface of the second lens, r4 is the radius of curvature of the image-side surface of the second lens, and d3 is the thickness of the second lens.
In the above optical lens, the fifth lens satisfies the following conditional expression (3):
0.3≤(r9-d9)/r10≤1 (3)
wherein r9 is a radius of curvature of an object-side surface of the fifth lens, r10 is a radius of curvature of an image-side surface of the fifth lens, and d9 is a thickness of the fifth lens.
In the above optical lens, the third lens and the fourth lens satisfy the following conditional expression (4):
-1≤F3/F4≤-1.5 (4)
wherein F3 is a focal length value of the third lens and F4 is a focal length value of the fourth lens.
In the above optical lens, the fifth lens satisfies the following conditional expression (5):
Nd5≥1.58 (5)
wherein Nd5 is a refractive index of the fifth lens.
In the above optical lens, the second lens and the fifth lens satisfy the following conditional expression (6):
F2/F5≤-4 (6)
wherein F2 is a focal length value of the second lens and F5 is a focal length value of the fifth lens.
In the above optical lens, the first lens to the fifth lens satisfy the following conditional expression (7):
TTL/F≤1.6 (7)
wherein F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.
The optical lens provided by the invention can realize small FNO, small distortion, low cost and high thermal stability while keeping the miniaturization of the lens by optimally setting the shape of each lens and reasonably distributing the focal power of each lens.
Drawings
Fig. 1 illustrates a lens configuration of an optical lens according to a first embodiment of the present invention;
fig. 2 illustrates a lens configuration of an optical lens according to a second embodiment of the present invention;
fig. 3 illustrates a lens configuration of an optical lens according to a third embodiment of the present invention.
Detailed Description
The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art. The basic principles of the invention, as defined in the following description, may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the invention.
The terms and words used in the following specification and claims are not limited to the literal meanings, but are used only by the inventors to enable a clear and consistent understanding of the invention. Accordingly, it will be apparent to those skilled in the art that the following descriptions of the various embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
The terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, numbers, steps, operations, components, elements, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, elements, or groups thereof.
Terms used herein, including technical and scientific terms, have the same meaning as terms commonly understood by one of ordinary skill in the art, unless otherwise defined. It will be understood that terms defined in commonly used dictionaries have meanings that are consistent with their meanings in the prior art.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
The invention is described in further detail below with reference to the following figures and detailed description:
[ arrangement of optical lens ]
According to an aspect of the embodiments of the present invention, there is provided an optical lens, in order from an object side to an image side, including: a first lens having a positive refractive power; the second lens is a meniscus lens with negative focal power, and the object side surface of the second lens is a convex surface and the image side surface of the second lens is a concave surface; a third lens having a negative focal power; a fourth lens having a positive refractive power; and a fifth lens element having a meniscus shape with a positive refractive power, the object-side surface of the fifth lens element being convex and the image-side surface of the fifth lens element being concave.
Thus, the optical lens according to the embodiment of the present invention can realize small FNO, small distortion, low cost, and high thermal stability while keeping the lens compact by optimally setting the shapes of the respective lenses and reasonably distributing the powers of the respective lenses.
The optical lens according to the embodiment of the invention realizes the small FNO by increasing the aperture of the diaphragm, and as described above, the small FNO can increase the light incidence amount, and is particularly suitable for the lens requirements of large light incidence amount like a laser radar lens.
Moreover, the optical lens according to the embodiment of the invention particularly meets the functional requirement of the laser radar small diffuse spot, as mentioned above, the diffuse spot is generally controlled within a half range of the pixel size, while the optical lens according to the embodiment of the invention can control the diffuse spot size to be less than one tenth of the pixel size when the FNO is 1.2, which is far better than the conventional requirement.
Specifically, in the optical lens according to the embodiment of the present invention, the second lens and the fifth lens are meniscus lenses convex toward the object side, and preferably the same material is used. Thus, the stability of the lens can be realized by adjusting the focal length ratio of the two lenses during design, namely, the optical lens can normally work at low temperature and high temperature. This will be described in further detail below.
In addition, in the optical lens according to the embodiment of the present invention, the second lens and the fifth lens are preferably designed in a special shape, for example, a design close to concentric circles, so as to contribute to reduction of optical aberration and reduction of a size of a dispersed spot.
For example, the second lens and the fifth lens are preferably plastic aspheric lenses, and the cost of the optical lens can be reduced by adopting a plastic aspheric surface processing mode. Here, the plastic aspherical lens is lower in cost than the glass aspherical lens and is suitable for mass production. Of course, it will be understood by those skilled in the art that the second lens and the fifth lens may also be glass aspheric lenses without limiting the cost, thereby obtaining more stable optical performance.
That is, in the optical lens according to the embodiment of the present invention, the second lens and the fifth lens are aspherical lenses.
Therefore, the optical lens according to the embodiment of the invention can reduce optical aberration and reduce the dispersed spot by adopting 2 plastic aspheric lenses, and the two plastic aspheric lenses are designed into special shapes to further reduce the dispersed spot, so that the dispersed spot is smaller than one tenth of the pixel size, and the usability of the optical lens is effectively ensured. Here, even if a machining tolerance is introduced, the size of the dispersed spot is always kept within a half range of the size of the pixel, so that the requirement of the optical lens for the small dispersed spot is met.
And the optical lens can be subjected to athermal treatment by adjusting the focal length ratio of the two plastic lenses, so that the dispersed spot is always smaller than half of the pixel size in the range of-40-105 ℃.
In addition, in the optical lens according to the embodiment of the present invention, the third lens and the fourth lens are preferably cemented lenses with a front negative film, and the focal lengths of the two lenses are relatively close in size, so as to help cancel out positive and negative aberrations introduced by the previous optical system, thereby reducing the speckle.
Hereinafter, each lens in the optical lens according to the embodiment of the present invention will be described in detail.
In the optical lens system according to the embodiment of the invention, the first lens element is a meniscus lens element, and the object-side surface of the first lens element is convex and the image-side surface of the first lens element is concave.
Therefore, the first lens can collect light rays in a field of view as much as possible, and the first lens adopts a meniscus shape, so that the caliber of the second lens and the distance between the first lens and the second lens can be effectively reduced, the total length TTL of the optical lens is effectively controlled, and the miniaturization of the optical lens is realized.
Also, the first lens preferably satisfies the following conditional expression (1):
Nd1≥1.66 (1)
where Nd1 is the refractive index of the first lens.
In this way, by setting the refractive index of the first lens, the thickness of the first lens can be reduced, thereby further contributing to shortening the total optical lens length TTL.
The second lens is a meniscus lens which is convex to the object space, has a negative light angle, can further converge light rays, and slowly transits the light rays to the third lens, so that the aberration generated by the first lens is reduced, and the distortion is reduced.
Also, the shape of the second lens is preferably of near-concentric design. That is, the second lens preferably satisfies the following conditional expression (2):
0.6≤(r3-d3)/r4≤1 (2)
where r3 is the radius of curvature of the object-side surface of the second lens, r4 is the radius of curvature of the image-side surface of the second lens, and d3 is the thickness of the second lens.
In addition, the shape of the fifth lens is preferably also of approximately concentric design. That is, the fifth lens preferably satisfies the following conditional expression (3):
0.3≤(r9-d9)/r10≤1 (3)
where r9 is a radius of curvature of an object-side surface of the fifth lens, r10 is a radius of curvature of an image-side surface of the fifth lens, and d9 is a thickness of the fifth lens.
In the optical lens system according to the embodiment of the present application, the third lens element is a meniscus lens element, and the object-side surface of the third lens element is a concave surface and the image-side surface of the third lens element is a convex surface; the fourth lens element is a meniscus lens element with a concave object-side surface and a convex image-side surface.
Or, in the optical lens according to the embodiment of the present application, the third lens is a biconcave lens, and the object-side surface of the third lens is a concave surface and the image-side surface of the third lens is a concave surface; the fourth lens element is a biconvex lens element, and has a convex object-side surface and a convex image-side surface.
And, the third lens and the fourth lens are cemented lenses.
In this way, the double cemented lens group with the negative film in front is formed by the third lens and the fourth lens, contributing to further reduction of system aberration. And the focal length ratio of the two lenses can be adjusted, and when the focal lengths of the two lenses are relatively close, positive and negative aberrations introduced by the previous optical system can be effectively reduced, so that the speckle is reduced.
That is, the third lens and the fourth lens satisfy the following conditional expression (4):
-1≤F3/F4≤-1.5 (4)
where F3 is the focal length value of the third lens, and F4 is the focal length value of the fourth lens.
In the optical lens according to the embodiment of the present invention, the fifth lens is a meniscus lens convex toward the object, and the fifth lens is preferably a plastic aspherical lens, so that distortion and aberration of the entire optical system are reduced, and the image plane diffuse spot size is further reduced. Also, the refractive index of the fifth lens is preferably large so as to reduce the distance between the image-side surface of the fifth lens and the imaging surface, thereby compressing the total optical lens length TTL.
That is, the fifth lens preferably satisfies the following conditional expression (5):
Nd5≥1.58 (5)
where Nd5 is the refractive index of the fifth lens.
Also, as described above, the second lens and the fifth lens preferably satisfy the following conditional expression (6):
F2/F5≤-4 (6)
where F2 is the focal length value of the second lens, and F5 is the focal length value of the fifth lens.
Therefore, the focal length values of the second lens and the fifth lens meet the conditional expression, the temperature stability of the optical lens can be improved, and the diffuse spot change is ensured to be within a half range of the pixel size within the temperature range of-40 ℃ to 105 ℃.
In addition, in the optical lens according to the embodiment of the present invention, the first lens to the fifth lens satisfy the following conditional expression (7):
TTL/F≤1.6 (7)
wherein, F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.
That is, the optical lens according to the embodiment of the present invention can compress the lens thickness and the air space therebetween by optimally setting the shape of each lens and reasonably distributing the power of each lens, thereby achieving miniaturization of the optical lens as a whole.
Here, it is understood by those skilled in the art that the above-described conditional expressions (1) to (7) are in a parallel relationship and are not in a relationship associated with each other therebetween. That is, in the optical lens according to the embodiment of the present invention, only one or more of the conditional expressions (1) to (7) may be satisfied, and the above-described conditional expressions (1) to (7) may be all satisfied.
In addition, it will be understood by those skilled in the art that the optical lens according to the embodiment of the present invention may be used as a lens of, for example, a laser radar, and may also be applied to other optical lenses that need to achieve small distortion, small FNO, low cost, good temperature performance, and meet the demand for miniaturization. Accordingly, it is not intended that the optical lens according to the embodiment of the present invention be limited to only a certain specific application.
[ numerical example of optical lens ]
Hereinafter, specific embodiments and numerical examples of an optical lens according to an embodiment of the present invention, in which specific numerical values are applied to the respective embodiments, will be described with reference to the drawings and tables.
Some of the lenses used in the embodiments have an aspherical lens surface, and the aspherical surface shape is represented by the following expression (8):
wherein, z (h) is a distance rise from the vertex of the aspherical surface when the aspherical surface is at a position of height h in the optical axis direction.
c is 1/r, r represents the curvature radius of the lens surface, k is a conic coefficient, A, B, C, D and E are high-order aspheric coefficients, E in the coefficients represents scientific notation, E-05 represents 10-5。
In addition, Nd denotes a refractive index, and Vd denotes an abbe number.
First embodiment
As shown in fig. 1, an optical lens according to the first embodiment of the present invention includes, in order from an object side to an image side: a meniscus-shaped first lens L1 having positive power, having a convex object-side first surface S1 and a concave image-side second surface S2; a meniscus-shaped second lens L2 having a negative power, having a convex object-side first surface S3 and a concave image-side second surface S4; a diaphragm STO; a meniscus-shaped third lens L3 having a negative power, having a concave object-side first surface S6 and a convex image-side second surface S7; a meniscus-shaped fourth lens L4 having a positive power, having a concave object-side first surface S7 and a convex image-side second surface S8, the fourth lens L4 and the third lens L3 being cemented lenses; a meniscus-shaped fifth lens L5 having positive power, having a convex object-side first surface S9 and a concave image-side second surface S10; a planar lens L6 having a first surface S11 facing the object side and a second surface S12 facing the image side, typically a protective glass; the image plane L7 is typically a chip.
The lens data of the above lenses are shown in table 1 below:
[ TABLE 1 ]
| Surface of | Radius of | Thickness of | Nd | Vd |
| 1 | 19.42 | 5.5 | 1.77 | 49.6 |
| 2 | 38.81 | 0.2 | ||
| 3 | 17.33 | 7 | 1.58 | 30.2 |
| 4 | 13.61 | 3.14 | ||
| STO | Infinite number of elements | 7.61 | ||
| 6 | -15.4 | 5.05 | 1.77 | 49.6 |
| 7 | -35.4 | 6.2 | 1.85 | 23.8 |
| 8 | -16 | 0.2 | ||
| 9 | 11 | 6.07 | 1.58 | 30.2 |
| 10 | 14.22 | 5.63 | ||
| 11 | Infinite number of elements | 0.5 | 1.52 | 64.2 |
| 12 | Infinite number of elements | 0.5 | ||
| IMA | Infinite number of elements |
The conic coefficients k and the high-order aspherical coefficients A, B, C, D and E of the first surface S3 and the second surface S4 of the second lens, and the first surface S9 and the second surface S10 of the fifth lens are shown in table 2 below.
[ TABLE 2 ]
| Surface of | k | A | B | C | D | E |
| 3 | -9.96899557 | 2.4573E-04 | -1.9557E-06 | 1.8879E-08 | -1.0072E-10 | 2.7369E-13 |
| 4 | 1.53497688 | 6.2708E-05 | -1.1916E-06 | 6.2589E-08 | -1.1565E-09 | 9.5177E-12 |
| 9 | -2.36365762 | 2.0842E-04 | -5.0295E-07 | -1.3874E-09 | 1.5123E-10 | -1.3076E-12 |
| 10 | 1.37129583 | 2.8784E-05 | -4.0912E-07 | -1.5771E-08 | 3.0042E-10 | -7.8274E-12 |
In the optical lens according to the first embodiment of the present invention, a curvature radius R3 of the first surface S3 of the second lens, a curvature radius R4 of the second surface S4 of the second lens, a thickness d3 of the second lens, and a relationship therebetween, a curvature radius R9 of the first surface S9 of the fifth lens, a curvature radius R10 of the second surface S10 of the fifth lens, a thickness d9 of the fifth lens, and a relationship therebetween, a focal length value F3 of the third lens, a focal length value F4 of the fourth lens, and a relationship therebetween, a focal length value F2 of the second lens, a focal length value F5 of the fifth lens, and a relationship therebetween, a refractive index Nd1 of the first lens, a refractive index Nd5 of the fifth lens, and a full-group focal length value F of the optical lens, an optical length TTL of the optical lens, and a relationship therebetween are shown in table 3 below.
[ TABLE 3 ]
As can be seen from table 3 above, the optical lens according to the first embodiment of the present invention satisfies the aforementioned conditional expressions (1) to (7), thereby achieving small distortion, small FNO, low cost, and good temperature performance while keeping the optical lens compact.
Second embodiment
As shown in fig. 2, the optical lens according to the second embodiment of the present invention, in order from an object side to an image side, comprises: a meniscus-shaped first lens L1 having positive power, having a convex object-side first surface S1 and a concave image-side second surface S2; a meniscus-shaped second lens L2 having a negative power, having a convex object-side first surface S3 and a concave image-side second surface S4; a diaphragm STO; a biconcave third lens L3 having a negative power, having a concave object-side first surface S6 and a concave image-side second surface S7; a biconvex fourth lens L4 having a positive optical power and having a first surface S7 convex to the object side and a second surface S8 convex to the image side, the fourth lens L4 and the third lens L3 being cemented lenses; a meniscus-shaped fifth lens L5 having positive power, having a convex object-side first surface S9 and a concave image-side second surface S10; a planar lens L6 having a first surface S11 facing the object side and a second surface S12 facing the image side, typically a protective glass; the image plane L7 is typically a chip.
The lens data for the above lenses are shown in table 4 below:
[ TABLE 4 ]
| Surface of | Radius of | Thickness of | Nd | Vd |
| 1 | 18.06 | 6.5 | 1.68 | 57.4 |
| 2 | 86.54 | 0.17 | ||
| 3 | 13.41 | 5.58 | 1.64 | 23.9 |
| 4 | 10.83 | 1.76 | ||
| STO | Infinite number of elements | 5.09 | ||
| 6 | -20.21 | 2.6 | 1.77 | 49.6 |
| 7 | 99.99 | 5.97 | 1.85 | 23.8 |
| 8 | -18.99 | 0.17 | ||
| 9 | 10.06 | 2.26 | 1.64 | 23.9 |
| 10 | 11.32 | 5.09 | ||
| 11 | Infinite number of elements | 0.5 | 1.52 | 64.2 |
| 12 | Infinite number of elements | 0.5 | ||
| IMA | Infinite number of elements |
The conic coefficients k and the high-order aspherical coefficients A, B, C, D and E of the first surface S3 and the second surface S4 of the second lens, and the first surface S9 and the second surface S10 of the fifth lens are shown in table 5 below.
[ TABLE 5 ]
| Surface of | k | A | B | C | D | E |
| 3 | -6.79266292 | 2.5241E-04 | -1.3053E-06 | 8.3909E-09 | -5.3454E-11 | 2.7488E-13 |
| 4 | 0.267033765 | -7.7295E-07 | -3.5608E-06 | 1.5820E-07 | -1.6112E-10 | -3.6556E-11 |
| 9 | -6.82088444 | 6.1031E-04 | -4.6952E-06 | -7.1248E-08 | 5.2274E-10 | -1.5201E-11 |
| 10 | 0.958129237 | 3.0116E-05 | 1.8256E-05 | -9.8745E-07 | 1.7924E-08 | -1.6279E-10 |
In the optical lens according to the second embodiment of the present invention, a curvature radius R3 of the first surface S3 of the second lens, a curvature radius R4 of the second surface S4 of the second lens, a thickness d3 of the second lens, and a relationship therebetween, a curvature radius R9 of the first surface S9 of the fifth lens, a curvature radius R10 of the second surface S10 of the fifth lens, a thickness d9 of the fifth lens, and a relationship therebetween, a focal length value F3 of the third lens, a focal length value F4 of the fourth lens, and a relationship therebetween, a focal length value F2 of the second lens, a focal length value F5 of the fifth lens, and a relationship therebetween, a refractive index Nd1 of the first lens, a refractive index Nd5 of the fifth lens, and a full-group focal length value F of the optical lens, an optical length TTL of the optical lens, and a relationship therebetween are shown in table 6 below.
[ TABLE 6 ]
As can be seen from table 6 above, the optical lens according to the second embodiment of the present invention satisfies the aforementioned conditional expressions (1) to (7), thereby achieving small distortion, small FNO, low cost, and good temperature performance while keeping the optical lens compact.
Third embodiment
As shown in fig. 3, the optical lens according to the third embodiment of the present invention, in order from the object side to the image side, comprises: a meniscus-shaped first lens L1 having positive power, having a convex object-side first surface S1 and a concave image-side second surface S2; a meniscus-shaped second lens L2 having a negative power, having a convex object-side first surface S3 and a concave image-side second surface S4; a diaphragm STO; a biconcave third lens L3 having a negative power, having a concave object-side first surface S6 and a concave image-side second surface S7; a biconvex fourth lens L4 having a positive optical power and having a first surface S7 convex to the object side and a second surface S8 convex to the image side, the fourth lens L4 and the third lens L3 being cemented lenses; a meniscus-shaped fifth lens L5 having positive power, having a convex object-side first surface S9 and a concave image-side second surface S10; a planar lens L6 having a first surface S11 facing the object side and a second surface S12 facing the image side, typically a protective glass; the image plane L7 is typically a chip.
The lens data for the above lenses are shown in table 7 below:
[ TABLE 7 ]
The conic coefficients k and the high-order aspherical coefficients A, B, C, D and E of the first surface S3 and the second surface S4 of the second lens, and the first surface S9 and the second surface S10 of the fifth lens are shown in table 8 below.
[ TABLE 8 ]
| Surface of | k | A | B | C | D | E |
| 3 | -8.53381169 | 2.4723E-04 | -1.9566E-06 | 1.8490E-08 | -9.8532E-11 | 2.6555E-13 |
| 4 | -0.226721065 | 1.2473E-04 | -7.5106E-07 | 8.1180E-08 | -1.5053E-09 | 1.4185E-11 |
| 9 | -3.47445992 | 1.4909E-04 | -1.7093E-06 | -1.7533E-08 | 2.9385E-10 | -2.7100E-12 |
| 10 | 0.706079001 | -8.4231E-05 | -1.9914E-06 | -3.5255E-08 | 7.4240E-11 | -3.5647E-12 |
In the optical lens according to the third embodiment of the present invention, the curvature radius R3 of the first surface S3 of the second lens, the curvature radius R4 of the second surface S4 of the second lens, the thickness d3 of the second lens, and the relationship therebetween, the curvature radius R9 of the first surface S9 of the fifth lens, the curvature radius R10 of the second surface S10 of the fifth lens, the thickness d9 of the fifth lens, and the relationship therebetween, the focal length value F3 of the third lens, the focal length value F4 of the fourth lens, and the relationship therebetween, the focal length value F2 of the second lens, the focal length value F5 of the fifth lens, and the relationship therebetween, the refractive index Nd1 of the first lens, the refractive index Nd5 of the fifth lens, and the entire group focal length value F of the optical lens, the optical length of the optical lens, and the relationship therebetween are as shown in table 9 below.
[ TABLE 9 ]
As can be seen from table 9 above, the optical lens according to the third embodiment of the present invention satisfies the aforementioned conditional expressions (1) to (7), thereby achieving small distortion, small FNO, low cost, and good temperature performance while keeping the optical lens compact.
In summary, the optical lens according to the embodiment of the present invention can achieve small FNO, small distortion, low cost, and high thermal stability while keeping the lens compact by optimally setting the shapes of the respective lenses and reasonably distributing the powers of the respective lenses.
According to the optical lens disclosed by the embodiment of the invention, the second lens and the fifth lens are meniscus lenses which are convex towards the object side, so that the aberration and the distortion of an optical system can be reduced.
According to the optical lens provided by the embodiment of the invention, the second lens and the fifth lens are in the shapes close to concentric circles, so that the optical aberration can be reduced, and the size of a dispersed spot can be reduced.
According to the optical lens provided by the embodiment of the invention, the high thermal stability of the optical lens can be realized by adjusting the focal length ratio of the second lens and the fifth lens.
According to the optical lens disclosed by the embodiment of the invention, the second lens and the fifth lens are plastic aspheric lenses, so that the low cost of the optical lens can be realized.
According to the optical lens disclosed by the embodiment of the invention, the first lens is the meniscus lens which is convex to the object, so that the caliber of the second lens and the distance between the first lens and the second lens can be effectively reduced, and the miniaturization of the optical lens is facilitated.
According to the optical lens disclosed by the embodiment of the invention, the refractive index of the first lens is more than or equal to 1.66, so that the thickness of the first lens is reduced, and the miniaturization of the optical lens is realized.
The optical lens according to the embodiment of the present invention forms a cemented lens with a negative film in front by the third lens and the fourth lens, which contributes to further reducing system aberration.
According to the optical lens disclosed by the embodiment of the invention, the focal length ratio of the third lens and the fourth lens is adjusted to enable the focal lengths of the third lens and the fourth lens to be close to each other, so that positive and negative aberrations introduced by the object-side optical system can be effectively reduced, and the scattered spot is reduced.
According to the optical lens disclosed by the embodiment of the invention, the refractive index of the fifth lens is larger than or equal to 1.58, so that the distance from the image side surface of the fifth lens to the imaging surface is reduced, and the miniaturization of the optical lens is realized.
Additional lenses may also be disposed in optical lenses according to embodiments of the present invention. In this case, the optical lens according to the embodiment of the present invention may be configured with six or more lenses, and the lenses include additional lenses arranged in addition to the above-described first to fifth lenses.
As described above, the optical lens according to the embodiment of the present invention can be applied to any optical lens requiring a small volume, small distortion, small FNO, low cost, and good temperature performance, and is not limited to a specific application field. For example, the optical lens according to the embodiment of the present invention may be applied to a laser radar, and the embodiment of the present invention is not intended to limit in any way.
It will be appreciated by persons skilled in the art that the embodiments of the invention described above and shown in the drawings are given by way of example only and are not limiting of the invention. The objects of the invention have been fully and effectively accomplished. The functional and structural principles of the present invention have been shown and described in the examples, and any variations or modifications of the embodiments of the present invention may be made without departing from the principles.
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Claims (13)
1. An optical lens in which the number of lenses having optical power is five, characterized in that the five lenses having optical power include, in order from an object side to an image side:
a first lens having a positive refractive power;
the second lens is a meniscus lens with negative focal power, and the object side surface of the second lens is a convex surface and the image side surface of the second lens is a concave surface;
a third lens having a negative focal power;
a fourth lens having a positive refractive power; and
a fifth lens element having a meniscus shape with a positive refractive power, the object-side surface of the fifth lens element being convex and the image-side surface of the fifth lens element being concave;
wherein the second lens and the fifth lens satisfy the following conditional expression (6):
F2/F5≤-4 （6）
wherein F2 is a focal length value of the second lens and F5 is a focal length value of the fifth lens.
2. An optical lens barrel according to claim 1, wherein the first lens element is a meniscus lens element having a convex object-side surface and a concave image-side surface.
3. An optical lens according to claim 1,
the third lens is a meniscus lens, and the object side surface of the third lens is a concave surface and the image side surface of the third lens is a convex surface; and
the fourth lens is a meniscus lens, and the object side surface of the fourth lens is a concave surface and the image side surface of the fourth lens is a convex surface.
4. An optical lens according to claim 3, characterized in that the third lens and the fourth lens are cemented lenses.
5. An optical lens according to claim 1,
the third lens is a biconcave lens, and the object side surface of the third lens is a concave surface and the image side surface of the third lens is a concave surface; and
the fourth lens is a biconvex lens, and the object side surface of the fourth lens is a convex surface and the image side surface of the fourth lens is a convex surface.
6. An optical lens according to claim 5, characterized in that the third lens and the fourth lens are cemented lenses.
7. An optical lens according to claim 1, characterized in that the second lens and the fifth lens are aspherical lenses.
8. An optical lens barrel according to any one of claims 1 to 7, wherein the first lens satisfies the following conditional expression (1):
Nd1≥1.66 （1）
wherein Nd1 is a refractive index of the first lens.
9. An optical lens barrel according to any one of claims 1 to 7, wherein the second lens satisfies the following conditional expression (2):
0.6 ≤（r3-d3）/r4≤1 （2）
where r3 is the radius of curvature of the object-side surface of the second lens, r4 is the radius of curvature of the image-side surface of the second lens, and d3 is the thickness of the second lens.
10. An optical lens barrel according to any one of claims 1 to 7, wherein the fifth lens satisfies the following conditional expression (3):
0.3 ≤（r9-d9）/r10≤1 （3）
wherein r9 is a radius of curvature of an object-side surface of the fifth lens, r10 is a radius of curvature of an image-side surface of the fifth lens, and d9 is a thickness of the fifth lens.
11. An optical lens according to any one of claims 1 to 7, wherein the third lens and the fourth lens satisfy the following conditional expression (4):
-1.5≤F3/F4≤-1 （4）
wherein F3 is a focal length value of the third lens and F4 is a focal length value of the fourth lens.
12. An optical lens barrel according to any one of claims 1 to 7, wherein the fifth lens satisfies the following conditional expression (5):
Nd5≥1.58 （5）
wherein Nd5 is a refractive index of the fifth lens.
13. An optical lens according to any one of claims 1 to 7, wherein the first lens to the fifth lens satisfy the following conditional expression (7):
TTL/F≤1.6 （7）
wherein F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.
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| US20010043409A1 (en) * | 2000-03-30 | 2001-11-22 | Fuji Photo Optical Co., Ltd. | Collimator lens and optical scanning apparatus using the same |
| JP2005316015A (en) * | 2004-04-27 | 2005-11-10 | Nidec Copal Corp | Imaging lens |
| CN106291877A (en) * | 2015-06-26 | 2017-01-04 | 先进光电科技股份有限公司 | Optical imaging system |
| CN106918894A (en) * | 2017-02-28 | 2017-07-04 | 信华精机有限公司 | A kind of small aberration optical lens |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20010043409A1 (en) * | 2000-03-30 | 2001-11-22 | Fuji Photo Optical Co., Ltd. | Collimator lens and optical scanning apparatus using the same |
| JP2005316015A (en) * | 2004-04-27 | 2005-11-10 | Nidec Copal Corp | Imaging lens |
| CN106291877A (en) * | 2015-06-26 | 2017-01-04 | 先进光电科技股份有限公司 | Optical imaging system |
| CN106918894A (en) * | 2017-02-28 | 2017-07-04 | 信华精机有限公司 | A kind of small aberration optical lens |
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