CN108663773B - Optical lens and imaging apparatus - Google Patents
Optical lens and imaging apparatus Download PDFInfo
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- CN108663773B CN108663773B CN201710208084.1A CN201710208084A CN108663773B CN 108663773 B CN108663773 B CN 108663773B CN 201710208084 A CN201710208084 A CN 201710208084A CN 108663773 B CN108663773 B CN 108663773B
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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 and an imaging apparatus. The optical lens includes, in order from an object side to an image side: a first lens, which is a meniscus lens with negative focal power, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens is a glass aspheric lens; a second lens having a negative focal power and a concave image-side surface; the third lens has positive focal power, and the image side surface of the third lens is a convex surface; a fourth lens; a fifth lens cemented with the fourth lens; and a sixth lens having a positive power. With the optical lens and the imaging apparatus according to the present invention, it is possible to obtain a high resolution while keeping the optical lens compact.
Description
Technical Field
The present invention relates to the field of optical lenses and imaging apparatuses, and particularly to an optical lens and an imaging apparatus capable of obtaining a high resolution while keeping the lens compact.
Background
Imaging apparatuses, such as camera-mounted mobile apparatuses and digital still cameras, using, for example, a Charge Coupled Device (CCD) and a Complementary Metal Oxide Semiconductor (CMOS) as a solid-state imaging element have been well known.
With the development of science and technology, the requirements for the resolution of optical lenses are higher and higher, and the requirements are continuously raised from the original million pixels to the direction of ten million pixels, and high-pixel lenses are more and more popular.
In addition, with the popularization of mobile devices, there is a need to apply imaging devices of increasingly small sizes, such as those applied to mobile phones, for which the demand for small sizes is very high.
In general, the resolution can be improved by increasing the number of lenses in the optical lens, but the size and weight of the optical lens are increased accordingly, which is disadvantageous to the miniaturization of the optical lens and causes an increase in cost.
At present, a wide-angle optical lens with mega pixels and more generally adopts 6 lenses, although the resolution is obviously improved compared with an optical lens with 5 lenses, the requirement for miniaturization is more prominent due to the increase of the number of the lenses.
Conventionally, in order to meet the demand for miniaturization of an optical lens, a scheme of compressing the optical total length of the lens is generally adopted, but the resolution is significantly affected. Meanwhile, the imaging quality can be improved by additionally adopting the aspheric lens, but the cost of the glass aspheric lens is higher, and the temperature performance of the lens is reduced due to excessive use of the plastic aspheric lens.
In particular, for a lens that operates in an outdoor environment, such as a monitor lens or a vehicle-mounted lens, on the one hand, the operating environment is variable, and it is necessary to maintain perfect resolution no matter in hot and high-temperature days or in cold and rainy and snowy days, and on the other hand, the installation space is limited. Therefore, how to obtain as high imaging quality as possible while ensuring miniaturization of the optical lens is a problem to be urgently solved.
Accordingly, there is a need for improved optical lenses and imaging devices.
Disclosure of Invention
An object of the present invention is to provide a novel and improved optical lens and imaging apparatus capable of achieving a high resolution while keeping the lens compact, in view of the above-mentioned drawbacks and disadvantages of the prior art.
An object of the present invention is to provide an optical lens and an imaging apparatus, which are advantageous to reduce a front end aperture of the optical lens by using a glass aspheric lens as a first lens in the optical lens, so as to reduce a radial volume of the optical lens, and thus reduce an entire volume of the optical lens.
An object of the present invention is to provide an optical lens and an imaging apparatus which contribute to obtaining a high resolving power while keeping the optical lens compact by the shape and power setting of a third lens in the optical lens.
An object of the present invention is to provide an optical lens and an imaging apparatus, which can reduce the rear port diameter/size of the optical lens by having a positive film in front and a negative film in rear of a fourth lens and a fifth lens cemented to each other, and by converging light rays by the positive film.
An object of the present invention is to provide an optical lens and an imaging apparatus, in which the third lens is a glass lens, which is beneficial to thermal compensation, and further the third lens is an aspheric glass lens, which can further improve the resolution.
An object of the present invention is to provide an optical lens and an imaging apparatus which can significantly shorten the optical length of the optical lens and improve the resolving power while ensuring the miniaturization of the optical lens by optimally setting the shapes of respective lenses and reasonably distributing the powers of the respective lenses.
An object of the present invention is to provide an optical lens and an imaging apparatus, which contribute to reducing the manufacturing cost of the whole optical lens by using at least two plastic aspherical lenses among the second lens to the sixth lens, and at the same time, can ensure good temperature performance while obtaining good imaging quality by using plastic lenses by optimally setting the shapes of the respective lenses and reasonably distributing the focal powers of the respective lenses.
An object of the present invention is to provide an optical lens and an imaging apparatus, which are advantageous to effectively converge light entering an optical system and reduce the lens aperture of the optical system by locating a diaphragm between a third lens and a fourth 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: the first lens is a meniscus lens with negative focal power, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens is a glass aspheric lens; the second lens has negative focal power, and the image side surface of the second lens is a concave surface; the third lens has positive focal power, and the image side surface of the third lens is a convex surface; a fourth lens; a fifth lens cemented with the fourth lens; and a sixth lens having a positive power.
In the above optical lens, the first lens satisfies the following conditional expression (1):
D/h/FOV≤0.025 (1)
the FOV is the maximum field angle of the optical lens, the D is the maximum clear aperture of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the h is the image height corresponding to the maximum field angle of the optical lens.
In the above optical lens system, the fourth lens element is a biconvex lens element with positive refractive power, and has a convex object-side surface and a convex image-side surface; and the fifth lens is a meniscus lens with negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface.
In the above optical lens assembly, the third lens element is a meniscus lens element, and the object side surface thereof is a concave surface.
In the above optical lens system, the third lens element is a biconvex lens element, an object-side surface of the third lens element is a convex surface, and an absolute value of a ratio of a radius of the object-side surface to a radius of the image-side surface is greater than or equal to 18, that is:
i R5/R6 ≧ 18(2)
Where R5 is a radius of an object side surface of the third lens, R6 is a radius of an image side surface of the third lens, and i R5/R6 i represents an absolute value of a ratio of the radius of the object side surface to the radius of the image side surface of the third lens.
In the above optical lens system, the second lens element is a meniscus lens element, and the object side surface thereof is a convex surface.
In the above optical lens, the second lens is a biconcave lens, and an object-side surface thereof is a concave surface.
In the above optical lens, at least two lenses of the second lens to the sixth lens are plastic aspherical lenses.
In the above optical lens, the third lens is a glass lens.
In the above optical lens, the third lens is a glass aspherical lens.
In the above optical lens, the optical lens further includes a diaphragm, the diaphragm being located between the third lens and the fourth lens.
In the optical lens assembly, an object-side surface of the sixth lens element is a convex surface, and an image-side surface of the sixth lens element is a convex surface.
In the above optical lens, the first lens to the sixth lens satisfy the following conditional expression (3):
F3/F≤5.5 (3)
where F3 is the focal length of the third lens, and F is the entire set of focal length values of the optical lens.
In the above optical lens, the first lens to the sixth lens satisfy the following conditional expression (4):
TTL/F≤14.5 (4)
wherein F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.
According to another aspect of the present invention, there is provided an imaging apparatus including the optical lens described above and an imaging element for converting an optical image formed by the optical lens into an electric signal.
According to the optical lens and the imaging device, the first lens in the optical lens is the glass aspheric lens, so that the front end caliber of the optical lens is reduced, the radial volume of the optical lens is reduced, and the whole volume of the optical lens is reduced.
In addition, the optical lens and the imaging apparatus provided by the present invention contribute to obtaining a high resolving power while keeping the optical lens compact by the shape and power setting of the third lens in the optical lens.
Further, the optical lens and the imaging device provided by the invention can remarkably shorten the optical length of the optical lens by optimally setting the shape of each lens and reasonably distributing the focal power of each lens, and improve the resolution while ensuring the miniaturization of the optical 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 is a schematic block diagram of an image forming apparatus according to an 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.
The invention is described in further detail below with reference to the following figures and detailed description:
[ arrangement of optical lens ]
According to the optical lens of the embodiment of the present invention, the optical lens includes, in order from an object side to an image side: the first lens is a meniscus lens with negative focal power, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens is a glass aspheric lens; the second lens is a lens with negative focal power, and the image side surface of the second lens is a concave surface; the third lens is a lens with positive focal power, and the image side surface of the third lens is a convex surface; a fourth lens; a fifth lens cemented with the fourth lens; the sixth lens element is a biconvex lens element with positive focal power, and has a convex object-side surface and a convex image-side surface.
In the optical lens according to the embodiment of the invention, the first lens is a glass aspheric lens, so that the front end aperture of the optical lens can be reduced, the radial volume of the optical lens can be reduced, and the resolution can be further improved.
The first lens can be made of glass materials with different refractive indexes, and the higher the refractive index of the material is, the more beneficial the optical path difference of the large-angle light rays entering the whole optical system is further reduced, thereby reducing the front end caliber of the optical lens.
Preferably, in the above optical lens, the first lens satisfies the following conditional expression (1):
D/h/FOV≤0.025 (1)
the FOV is the maximum field angle of the optical lens, the D is the maximum clear aperture of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the h is the image height corresponding to the maximum field angle of the optical lens.
In the above optical lens system, the third lens element is a meniscus lens element or a biconvex lens element having a positive refractive power, that is, the image-side surface of the third lens element is convex, and the object-side surface of the third lens element may be either convex or concave. When the third lens is a meniscus lens having positive power, it is helpful to obtain high resolving power while keeping the optical lens compact by the shape and power setting of the third lens in the optical lens.
In addition, when the third lens is a double-convex lens having positive optical power, the third lens needs to further satisfy the following conditional expression (2):
i R5/R6 ≧ 18(2)
Where R5 is a radius of an object side surface of the third lens, R6 is a radius of an image side surface of the third lens, and i R5/R6 i represents an absolute value of a ratio of the radius of the object side surface to the radius of the image side surface of the third lens.
In this way, by the shape and power setting of the third lens in the optical lens, it is helpful to obtain a high resolution while keeping the optical lens compact.
In the above optical lens, preferably, the fourth lens element is a biconvex lens element having a positive refractive power, and has a convex object-side surface and a convex image-side surface. In addition, the fifth lens is a meniscus lens with negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface. Thus, by viewing the positive film in front and the negative film behind from the incident direction of the light, the light can be converged by the positive film, and the rear port diameter/size of the optical lens can be reduced.
In the above optical lens, the second lens is a meniscus lens having a negative power or a biconcave lens having a negative power. That is, the image-side surface of the second lens element is concave, and the object-side surface can be convex or concave.
In the above optical lens, preferably, at least two lenses of the second lens to the sixth lens are plastic aspherical lenses. Thus, the manufacturing cost of the optical lens can be reduced by using the plastic aspherical lens. In addition, in the optical lens according to the embodiment of the invention, the shapes of the lenses are optimally set and the focal powers of the lenses are reasonably distributed, so that good imaging quality can be obtained by adopting the plastic lens, and meanwhile, better temperature performance is ensured.
In the above optical lens, preferably, the third lens is a glass lens, and more preferably, the third lens is an aspherical glass lens. When the third lens is a glass lens, thermal compensation is facilitated. In addition, when the third lens is an aspherical glass lens, the resolution can be further improved. Here, it may be understood by those skilled in the art that, in the optical lens according to the embodiment of the present invention, the third lens is not limited to only a glass lens or an aspherical glass lens. For example, the third lens may also be a plastic aspherical lens, which may achieve high resolution and low cost, but has poor temperature performance. Therefore, in practical applications, the mirror shape and material of the third lens can be determined according to specific requirements.
Preferably, in the above optical lens, the first lens to the sixth lens satisfy the following conditional expressions (3) and (4):
F3/F≤5.5 (3)
TTL/F≤14.5 (4)
where F3 is the focal length of the third lens, F is the entire group focal length value of the optical lens, and TTL is the optical length of the optical lens, i.e., the distance from the object-side outermost point of the first lens to the imaging focal plane.
Therefore, in the optical lens according to the embodiment of the present invention, due to the meniscus shape or the biconvex shape (the relationship between the radii of the object side and the image side) and the positive power setting of the third lens, it is possible to contribute to the formation of a short TTL, thereby achieving a miniaturized optical lens. Therefore, in the optical lens according to the embodiment of the present invention, the mirror shape and material of the third lens are not limited.
Here, it can be understood by those skilled in the art that, in the optical lens according to the embodiment of the present invention, in addition to the shape and power setting of the third lens, by optimally setting the shape of each lens and reasonably distributing the power of each lens, it is possible to significantly shorten the TTL and improve the resolution while ensuring the miniaturization of the optical lens.
In the above optical lens, a stop is further included. Preferably, the diaphragm is located between the third lens and the fourth lens, so that light rays entering the optical system are effectively converged, and the aperture of a lens of the optical system is reduced. Of course, the skilled person will understand that the diaphragm may also be located between any other discrete lenses.
In addition, in the case where the optical lens according to the embodiment of the present invention includes the diaphragm, it is preferable to dispose the fourth lens and the fifth lens cemented to each other at positions close to the diaphragm in consideration of the balance of system aberrations and the rationality of the structure.
Next, the structures and functions of the first to sixth lenses in the optical lens according to the embodiment of the present invention will be further described in detail.
In the optical lens system according to the embodiment of the invention, the first lens element has a meniscus shape convex toward the object side, and the object side surface of the first lens element is convex and the image side surface of the first lens element is concave. The convex surface of the first lens is curved toward the object side, so that the incident angle of the incident light on the attack surface is small, and more light can be collected to enter the optical system of the embodiment of the invention. In addition, when applied to an on-vehicle front view lens, the on-vehicle front view lens is used in an outdoor environment, and is subject to severe weather such as rain and snow, for example. The convexity is advantageous for accommodating outdoor use of the vehicle-mounted front view lens, for example, when in an environment such as rainy weather, the convexity may contribute to the sliding of water droplets, thereby reducing the influence on imaging.
In addition, the first lens is an aspheric glass lens. When the first lens is an aspheric glass lens, the caliber of the front end of the lens can be reduced, the whole volume of the lens can be reduced, and the resolution can be further improved.
In the optical lens system according to the embodiment of the invention, the second lens element is a meniscus lens element or a biconcave lens element with a concave image-side surface, and the object-side surface of the second lens element may be a convex surface or a concave surface. Because the first lens of the optical lens is a divergent lens, the light rays collected by the first lens are compressed by the configuration of the second lens, so that the trend of the light rays is relatively gentle, and the light rays are smoothly transited to the rear.
In the optical lens system according to the embodiment of the invention, the third lens element is a meniscus lens element or a biconvex lens element having a convex image-side surface, and the object-side surface of the third lens element may be a concave surface or a convex surface. The third lens is a convergent lens, so that the divergent light rays smoothly enter the rear part. In addition, the third lens can balance and compensate spherical aberration and positional chromatic aberration introduced by the first lens and the second lens. In addition, as described above, the shape and focal power of the third lens are set more reasonably, which is beneficial to shortening the total length of the optical system and maintaining the high resolution of the whole optical lens.
In the optical lens barrel according to the embodiment of the present invention, a stop is located between the third lens and the fourth and fifth lenses cemented with each other, for converging front and rear light rays, shortening the total length of the optical system, and reducing the aperture of the front and rear lens groups.
In the optical lens according to the embodiment of the present invention, the fourth lens and the fifth lens cemented to each other can correct chromatic aberration by themselves, reduce tolerance sensitivity, and also can leave a part of chromatic aberration to balance chromatic aberration of the system. In addition, when viewed from the light incidence direction, the positive film with positive focal power is in front, the negative film with negative focal power is behind, the front light can be further converged and then transited to the rear, and the rear port diameter/size of the optical lens is reduced, so that the total length of the system is further reduced.
In the optical lens barrel according to the embodiment of the invention, the sixth lens element is a biconvex lens element, and the object-side surface of the sixth lens element is a convex surface and the image-side surface of the sixth lens element is a convex surface. Thus, the sixth lens is a converging lens, so that the light rays are converged. In addition, the sixth lens is preferably an aspheric lens, which can satisfy a system with a small FNO, such as FNO ≦ 2, while reducing the optical path length of the peripheral light to the imaging surface. Moreover, by using the aspheric surface, the sixth lens can perform a good correction function on the off-axis point aberration, and optimize the optical performance such as distortion, CRA and the like.
Here, it can be understood by those skilled in the art that the optical lens according to the embodiment of the present invention can be applied to other lens applications requiring light weight, miniaturization, low cost, and high resolution in addition to the vehicle-mounted front view lens, and the embodiment of the present invention is not intended to limit it in any way.
[ 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 shape is represented by the following expression (3):
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 radius of curvature 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, the 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 a negative power, having a first surface S1 convex toward the object side and a second surface S2 concave toward the image side, and the first lens L1 being a glass aspherical lens; 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 meniscus-shaped third lens L3 having positive power, having a concave object-side first surface S5 and a convex image-side second surface S6; a diaphragm STO; a fourth lens L4 and a fifth lens L5 cemented with each other, wherein the fourth lens L4 is a biconvex shape having a positive power, having a first surface S8 convex to the object side and a second surface S9 convex to the image side, the fifth lens L5 is a meniscus shape having a negative power, having a first surface S9 concave to the object side and a second surface S10 convex to the image side; a biconvex sixth lens L6 having positive optical power and having a first surface S11 convex to the object side and a second surface S12 convex to the image side; a planar lens L7 having a first surface S13 facing the object side and a second surface S14 facing the image side, typically a color filter; a planar lens L8 having a first surface S15 facing the object side and a second surface S16 facing the image side, typically a protective glass, for protecting the image plane; l9 has an image plane S17, typically a chip.
The lens data of the above lenses are shown in table 1 below:
[ TABLE 1 ]
The conic coefficients k and high-order aspherical coefficients A, B, C, D and E of the first surface S1 and the second surface S2 of the first lens, the first surface S3 and the second surface S4 of the second lens, the first surface S5 and the second surface S6 of the third lens, the surfaces S8, S9, and S10 of the fourth lens and the fifth lens, and the first surface S11 and the second surface S12 of the sixth lens are shown in table 2 below.
[ TABLE 2 ]
| Surface of | k | A | B | C | D | E |
| 1 | -0.0200 | -1.3635E-06 | -2.4612E-08 | -4.8205E-10 | -1.1739E-10 | -3.4923E-11 |
| 2 | -0.3500 | 1.6673E-04 | 5.6200E-06 | 3.7978E-07 | 2.6315E-08 | 1.8612E-09 |
| 3 | -133.0000 | 4.7695E-04 | -4.3011E-04 | 3.6588E-05 | -1.0694E-06 | 5.3168E-07 |
| 4 | -0.9948 | 4.4229E-03 | 9.5164E-04 | 3.6629E-04 | -4.7785E-04 | 4.1163E-05 |
| 5 | 68.5768 | -2.5613E-03 | 1.6128E-03 | -3.5298E-04 | -8.1825E-04 | 3.0571E-04 |
| 6 | -5.1729 | 2.8901E-03 | -3.6462E-04 | -7.1091E-04 | 6.2587E-04 | -1.2061E-04 |
| 8 | 12.3781 | 2.7340E-02 | 1.0211E-03 | 4.4354E-03 | -1.2705E-02 | 5.7400E-03 |
| 9 | -0.8500 | -6.3487E-02 | 3.8909E-02 | -4.4622E-02 | 4.2758E-02 | -6.7932E-02 |
| 10 | 266.4128 | 2.9000E-03 | 4.3516E-03 | 1.0665E-03 | -1.5724E-04 | -4.8647E-05 |
| 11 | -8.2360 | 2.6362E-03 | 2.5918E-03 | -1.1583E-05 | 4.3638E-05 | -4.4208E-05 |
| 12 | -3.7554 | 7.1899E-03 | -1.9305E-04 | 6.8446E-04 | -1.1621E-04 | 4.1776E-05 |
In the optical lens according to the first embodiment of the present invention, the focal length F3 of the third lens, the entire group focal length value F of the optical lens, and the optical length TTL of the optical lens and the relationship therebetween, the radii R5 and R6 of the object-side and image-side surfaces of the third lens, and the D, h, FOV of the first lens and the relationship therebetween are as shown in table 3 below.
[ TABLE 3 ]
| F3 | 4.541206 |
| F | 1.08789 |
| TTL | 14.8003 |
| F3/F | 4.17432461 |
| TTL/F | 13.60459238 |
| D | 6.51992 |
| h | 2.728 |
| FOV | 134 |
| D/h/FOV | 0.017835821 |
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), (3), and (4), thereby shortening the TTL while reducing the radial dimension of the optical lens, and obtaining a high resolving power while maintaining the miniaturization of the optical lens.
Here, as can be understood by those skilled in the art, since the third lens is a meniscus lens having positive power, the absolute value of the ratio of the radii of the object side surface and the image side surface thereof does not need to satisfy the aforementioned conditional expression (2), and a short TTL of the optical lens can also be achieved.
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 a negative power, having a first surface S1 convex toward the object side and a second surface S2 concave toward the image side, and the first lens L1 being a glass aspherical lens; a biconcave second lens L2 having a negative power, having a concave object-side first surface S3 and a concave image-side second surface S4; a biconvex third lens L3 having positive optical power and having a first surface S5 convex to the object side and a second surface S6 convex to the image side; a diaphragm STO; a fourth lens L4 and a fifth lens L5 cemented with each other, wherein the fourth lens L4 is a biconvex shape having a positive power, having a first surface S8 convex to the object side and a second surface S9 convex to the image side, the fifth lens L5 is a meniscus shape having a negative power, having a first surface S9 concave to the object side and a second surface S10 convex to the image side; a biconvex sixth lens L6 having positive optical power and having a first surface S11 convex to the object side and a second surface S12 convex to the image side; a planar lens L7 having a first surface S13 facing the object side and a second surface S14 facing the image side, typically a color filter; a planar lens L8 having a first surface S15 facing the object side and a second surface S16 facing the image side, typically a protective glass, for protecting the image plane; l9 has an image plane S17, typically a chip.
The lens data for the above lenses are shown in table 4 below:
[ TABLE 4 ]
The conic coefficients k and high-order aspherical coefficients A, B, C, D and E of the first surface S1 and the second surface S2 of the first lens, the first surface S3 and the second surface S4 of the second lens, the surfaces S8, S9, and S10 of the fourth lens and the fifth lens, and the first surface S11 and the second surface S12 of the sixth lens are shown in table 5 below.
[ TABLE 5 ]
| Surface of | k | A | B | C | D | E |
| 1 | 0.0127 | -2.0667E-05 | -2.2573E-07 | -2.0927E-08 | 2.2578E-11 | 0.0000E+00 |
| 2 | 0.0000 | -3.3822E-04 | 8.6958E-05 | -2.3230E-05 | 1.3629E-06 | 0.0000E+00 |
| 3 | 1534.7180 | -6.4575E-03 | -5.0394E-04 | 3.2057E-05 | -1.6068E-06 | 2.0054E-07 |
| 4 | -0.5933 | 2.2310E-02 | 8.9207E-03 | -2.5098E-04 | -6.9060E-04 | -2.5216E-05 |
| 8 | -0.2932 | 1.2912E-02 | -2.6439E-02 | 1.1883E-02 | -7.1236E-03 | 1.1831E-03 |
| 9 | -2.0579 | -1.0749E-01 | -2.4809E-02 | -6.1273E-02 | 2.4917E-02 | -6.9088E-02 |
| 10 | 220.5605 | -3.6755E-03 | -1.9710E-05 | 5.8986E-05 | -6.0291E-05 | 9.5658E-05 |
| 11 | -8.8600 | -1.5311E-03 | 1.3092E-03 | -7.6798E-05 | 7.3002E-05 | -3.1036E-06 |
| 12 | 0.7851 | 3.4947E-03 | 3.4014E-03 | 1.0352E-03 | -1.3363E-04 | 2.4675E-05 |
In the optical lens according to the second embodiment of the present invention, the focal length F3 of the third lens, the entire group focal length value F of the optical lens, and the optical length TTL of the optical lens and the relationship therebetween, the radii R5 and R6 of the object-side and image-side surfaces of the third lens and the relationship therebetween, and the D, h, FOV of the first lens and the relationship therebetween are as shown in table 6 below.
[ TABLE 6 ]
| F3 | 5.909288 |
| F | 1.18857 |
| TTL | 14.0535 |
| F3/F | 4.971762706 |
| TTL/F | 11.82387238 |
| R5 | 80.31332 |
| R6 | -4.076656 |
| I R5/R6I | 19.70078417 |
| D | 7.644252 |
| h | 2.838 |
| FOV | 134 |
| D/h/FOV | 0.020101007 |
As can be seen from table 6 above, the optical lens according to the first embodiment of the present invention satisfies the aforementioned conditional expressions (1), (2), (3), and (4), thereby shortening TTL while reducing the radial dimension of the optical lens, and obtaining high resolving power while maintaining the miniaturization of the optical lens.
In summary, in the optical lens according to the embodiment of the invention, the first lens in the optical lens is a glass aspheric lens, which is beneficial to reducing the front end aperture of the optical lens, so as to reduce the radial volume of the optical lens, and then reduce the overall volume of the optical lens.
In the optical lens according to the embodiment of the present invention, by the shape and power setting of the third lens in the optical lens, it is helpful to obtain a high resolving power while keeping the optical lens compact.
In the optical lens according to the embodiment of the present invention, by having the positive film in the fourth lens and the fifth lens cemented to each other in front and the negative film in back, the light can be converged by the positive film, reducing the rear port diameter/size of the optical lens.
In the optical lens according to the embodiment of the invention, the third lens is a glass lens, which is beneficial to thermal compensation, and the third lens is an aspheric glass lens, which can further improve the resolution.
In the optical lens according to the embodiment of the invention, by optimally setting the shapes of the lenses and reasonably distributing the focal powers of the lenses, the TTL can be remarkably shortened, and the resolving power is improved while the miniaturization of the optical lens is ensured.
In the optical lens according to the embodiment of the present invention, by employing at least two plastic aspherical lenses among the second lens to the sixth lens, it is possible to contribute to reduction in manufacturing cost of the optical lens as a whole. Meanwhile, by optimally setting the shapes of the lenses and reasonably distributing the focal power of the lenses, good imaging quality can be obtained by adopting the plastic lens, and meanwhile, better temperature performance is ensured.
In the optical lens according to the embodiment of the invention, the diaphragm is positioned between the third lens and the fourth lens, so that the light rays entering the optical system can be effectively converged, and the lens aperture of the optical system can be reduced.
In the optical lens according to the embodiment of the present invention, by disposing the fourth lens and the fifth lens cemented to each other at a position close to the stop, it is possible to contribute to the balance of system aberrations and the rationality of the structure.
In addition, in the optical lens according to the embodiment of the invention, the object side surface of the first lens is a convex surface, so that the incident angle of incident light on the attack surface is small, and more light rays can be collected. In addition, the convex object side surface of the first lens is a convex surface, so that the optical lens is suitable for outdoor use.
In addition, in the optical lens according to the embodiment of the invention, the first lens is the aspheric glass lens, so that the aperture of the front end of the lens can be reduced, the whole volume of the lens can be reduced, and the resolution can be further improved.
In addition, in the optical lens according to the embodiment of the invention, the second lens has negative focal power, so that the light collected by the first lens can be compressed by the configuration of the second lens, the trend of the light is relatively gentle, and the light can be smoothly transited to the rear.
In addition, in the optical lens according to the embodiment of the present invention, the third lens is a converging lens having positive refractive power, so that the divergent light rays smoothly enter the rear. And the third lens can balance and compensate spherical aberration and position chromatic aberration introduced by the first lens and the second lens.
In addition, in the optical lens according to the embodiment of the present invention, by the fourth lens and the fifth lens being cemented to each other, the fourth lens and the fifth lens themselves can correct chromatic aberration, reduce tolerance sensitivity, and also can leave a part of chromatic aberration to balance chromatic aberration of the system.
In addition, in the optical lens according to the embodiment of the present invention, the light rays are converged by the sixth lens being a converging lens having a positive power. Moreover, the sixth lens is an aspheric lens, so that a system with small FNO (ring edge optical element) can be met, for example, FNO is less than or equal to 2, the optical path of peripheral light rays reaching an imaging plane is reduced, good correction effect on axial and external point aberrations can be achieved, and optical performances such as distortion and CRA (crazing distortion) are optimized.
[ configuration of image Forming apparatus ]
According to another aspect of embodiments of the present invention, there is provided an imaging apparatus including an optical lens and an imaging element for converting an optical image formed by the optical lens into an electric signal, the optical lens including, in order from an object side to an image side: the first lens is a meniscus lens with negative focal power, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens is a glass aspheric lens; the second lens has negative focal power, and the image side surface of the second lens is a concave surface; the third lens has positive focal power, and the image side surface of the third lens is a convex surface; a fourth lens; a fifth lens cemented with the fourth lens; and a sixth lens having a positive power.
Fig. 3 is a schematic block diagram of an image forming apparatus according to an embodiment of the present invention. As shown in fig. 3, an imaging apparatus 100 according to an embodiment of the present invention includes an optical lens 101 and an imaging element 102. The optical lens 101 is used for capturing an optical image of a subject, and the imaging element 102 is used for converting the optical image captured by the optical lens 101 into an electrical signal.
In the above optical lens, the first lens satisfies the following conditional expression (1):
D/h/FOV≤0.025 (1)
the FOV is the maximum field angle of the optical lens, the D is the maximum clear aperture of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the h is the image height corresponding to the maximum field angle of the optical lens.
In the optical lens assembly, the fourth lens element is a biconvex lens element with positive refractive power, and has a convex object-side surface and a convex image-side surface; and the fifth lens is a meniscus lens with negative power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface.
In the above optical lens assembly, the third lens element is a meniscus lens element, and the object side surface thereof is a concave surface.
In the above optical lens system, the third lens element is a biconvex lens element, an object-side surface of the third lens element is a convex surface, and an absolute value of a ratio of a radius of the object-side surface to a radius of the image-side surface is greater than or equal to 18, that is:
i R5/R6 ≧ 18(2)
Where R5 is a radius of an object side surface of the third lens, R6 is a radius of an image side surface of the third lens, and i R5/R6 i represents an absolute value of a ratio of the radius of the object side surface to the radius of the image side surface of the third lens.
In the above optical lens system, the second lens element is a meniscus lens element, and the object side surface thereof is convex.
In the above optical lens, the second lens is a biconcave lens whose object-side surface is concave.
In the above optical lens, at least two lenses of the second lens to the sixth lens are plastic aspherical lenses.
In the above optical lens, the third lens is a glass lens.
In the above optical lens, the third lens is a glass aspherical lens.
In the above optical lens, the optical lens further includes a diaphragm located between the third lens and the fourth lens.
In the optical lens assembly, an object-side surface of the sixth lens element is convex, and an image-side surface of the sixth lens element is convex.
In the above optical lens, the first lens to the sixth lens satisfy the following conditional expression (3):
F3/F≤5.5 (3)
wherein, F3 is the focal length of the third lens, and F is the whole focal length of the optical lens.
In the above optical lens, the first lens to the sixth lens satisfy the following conditional expression (4):
TTL/F≤14.5 (4)
wherein, F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.
Here, it can be understood by those skilled in the art that other details of the optical lens in the imaging apparatus according to the embodiment of the present invention are the same as those described above with respect to the optical lens according to the embodiment of the present invention, and the aforementioned numerical examples of the optical lens according to the first embodiment to the second embodiment of the present invention may be adopted, and thus, no trace is made to avoid redundancy.
According to the optical lens and the imaging device, the first lens in the optical lens is the glass aspheric lens, so that the front end caliber of the optical lens is reduced, the radial volume of the optical lens is reduced, and the whole volume of the optical lens is reduced.
Also, the optical lens and the imaging apparatus according to the embodiments of the present invention contribute to obtaining a high resolving power while keeping the optical lens compact by the shape and power setting of the third lens in the optical lens.
Further, the optical lens and the imaging apparatus according to the embodiments of the present invention can significantly shorten TTL and improve resolution while ensuring miniaturization of the optical lens by optimally setting the shapes of the respective lenses and reasonably distributing the powers of the respective lenses.
According to the optical lens and the imaging device, the optical lens and the imaging device are provided with the fourth lens and the fifth lens which are glued with each other, the positive film is in front, the negative film is behind, light can be converged through the positive film, and the rear port diameter/size of the optical lens is reduced.
According to the optical lens and the imaging device provided by the embodiment of the invention, the third lens is the glass lens, so that the thermal compensation is facilitated, and the third lens is the aspheric glass lens, so that the resolution can be further improved.
The optical lens and the imaging apparatus according to the embodiments of the present invention contribute to reducing the manufacturing cost of the optical lens as a whole by employing at least two plastic aspherical lenses among the second lens to the sixth lens. Meanwhile, by optimally setting the shapes of the lenses and reasonably distributing the focal power of the lenses, good imaging quality can be obtained by adopting the plastic lens, and meanwhile, better temperature performance is ensured.
According to the optical lens and the imaging device provided by the embodiment of the invention, the diaphragm is positioned between the third lens and the fourth lens, so that the light rays entering the optical system can be effectively converged, and the lens aperture of the optical system is reduced.
Further, the optical lens and the imaging apparatus according to the embodiment of the present invention contribute to balance of system aberrations and rationality of structure by disposing the fourth lens and the fifth lens cemented to each other at a position close to the diaphragm.
In the optical lens and the imaging apparatus according to the embodiments of the present invention, a lens having substantially no lens power may also be arranged. Therefore, in addition to the first to sixth lenses described above, additional lenses may be arranged. In this case, the optical lens and the imaging apparatus according to the embodiment of the present invention may be configured with six or more lenses, and these lenses include additional lenses arranged in addition to the above-described first to sixth lenses.
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.
Claims (14)
1. An optical lens comprising, in order from an object side to an image side:
the first lens is a meniscus lens with negative focal power, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens is a glass aspheric lens;
the second lens has negative focal power, and the image side surface of the second lens is a concave surface;
the third lens has positive focal power, the image side surface of the third lens is a convex surface, and the object side surface of the third lens is a convex surface;
a fourth lens;
a fifth lens cemented with the fourth lens; and
a sixth lens having a positive optical power,
wherein the first lens to the sixth lens satisfy the following conditional expression (4):
TTL/F≤14.5 (4)
wherein F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.
2. An optical lens according to claim 1, wherein the first lens satisfies the following conditional expression (1):
D/h/FOV≤0.025 (1)
the FOV is the maximum field angle of the optical lens, the D is the maximum clear aperture of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the h is the image height corresponding to the maximum field angle of the optical lens.
3. An optical lens according to claim 1,
the fourth lens is a biconvex lens with positive focal power, 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; and
the fifth lens is a meniscus lens with negative focal power, and the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface.
4. An optical lens according to claim 1,
the third lens element is a biconvex lens element, and an absolute value of a ratio of a radius of the object-side surface to a radius of the image-side surface is greater than or equal to 18, that is:
R5/R6I ≧ 18(2) wherein R5 is the radius of the object-side face of the third lens, R6 is the radius of the image-side face of the third lens, and R5/R6I represents the absolute value of the ratio of the radius of the object-side face to the radius of the image-side face of the third lens.
5. An optical lens according to claim 1,
the second lens is a meniscus lens with a convex object-side surface.
6. An optical lens according to claim 1,
the second lens is a biconcave lens, and the object side surface of the second lens is a concave surface.
7. An optical lens according to any one of claims 1 to 6, characterized in that at least two lenses of the second lens to the sixth lens are plastic aspherical lenses.
8. An optical lens barrel according to any one of claims 1 to 6, wherein the third lens is a glass lens.
9. An optical lens according to claim 8, characterized in that the third lens is a glass aspherical lens.
10. An optical lens according to any one of claims 1 to 6, characterized in that the optical lens further comprises an optical stop, which is located between the third lens and the fourth lens.
11. An optical lens according to any one of claims 1 to 6, wherein the first lens to the sixth lens satisfy the following conditional expression (3):
F3/F≤5.5 (3)
where F3 is the focal length of the third lens, and F is the entire set of focal length values of the optical lens.
12. An optical lens according to any one of claims 1 to 6, wherein the first lens to the sixth lens satisfy the following conditional expression (4):
TTL/F≤11.82 (4)
wherein F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.
13. An optical lens according to any one of claims 1 to 6, wherein the first lens to the sixth lens satisfy the following conditional expression (3):
F3/F≤4.97 (3)
where F3 is the focal length of the third lens, and F is the entire set of focal length values of the optical lens.
14. An imaging apparatus comprising the optical lens of any one of claims 1 to 13 and an imaging element for converting an optical image formed by the optical lens into an electric signal.
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| CN112987233B (en) * | 2019-12-12 | 2022-11-25 | 信泰光学(深圳)有限公司 | Wide-angle lens |
| CN115220203B (en) * | 2022-09-15 | 2023-01-20 | 江西联创电子有限公司 | Optical imaging lens |
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