CN109324384B - Optical lens - Google Patents

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 negative focal power and a meniscus shape, the object side being convex and the image side being concave; a second lens having a negative focal power and a meniscus shape, the object side surface being convex and the image side surface being concave; the third lens and the second lens are cemented lenses and have positive focal power and a meniscus shape, and the object side surface is a convex surface and the image side surface is a concave surface; a fourth lens having a positive focal power and a biconvex shape, wherein the object-side surface is a convex surface and the image-side surface is a convex surface; a fifth lens having a positive focal power and a biconvex shape, the object-side surface being a convex surface, the image-side surface being a convex surface; and a sixth lens element having a meniscus shape with a negative refractive power, the object-side surface being concave, and the image-side surface being convex. The optical lens provided by the invention can realize high resolving power, low aberration, low cost and better temperature performance while keeping the miniaturization of the lens by optimally setting the shapes of all the lenses and reasonably distributing the focal power of all the lenses.

Description

Optical lens

Technical Field

The present invention relates to the field of optical lenses, and more particularly, to an optical lens that improves imaging performance while maintaining miniaturization of the lens.

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.

In such an imaging apparatus, an optical lens is used to acquire an image of a subject. As more and more electronic devices apply imaging functions, the requirements for optical lenses are also higher and higher. For example, the resolution of the optical lens is required to be higher, the original megapixels are gradually increased toward the direction of tens of millions of pixels, and the high-pixel lens is more and more popular.

For example, an optical lens applied to a vehicle-mounted field, the demand for a small size of the optical lens is very high because of a restriction of a vehicle interior space. The current optical lens with megapixels and more usually adopts 6 lenses or 7 lenses or even more than 7 lenses, and although the resolution is obviously improved, the miniaturization and low cost of the optical lens are affected by the increase of the number of the lenses.

In addition, for an on-vehicle optical lens or the like, it is necessary to achieve low aberration, which is generally achieved by correcting aberration with an aspherical surface. When the aspheric surface is adopted to correct aberration, if the plastic aspheric lens is adopted, the plastic aspheric lens has poor temperature performance due to large thermal expansion coefficient, so that perfect imaging performance cannot be guaranteed within the temperature range of-40-85 ℃, and the problem of defocused image blur caused by temperature change exists. In contrast, if a glass aspherical lens is used to ensure the temperature characteristics, the cost is too high.

Also, the above-described problems exist with respect to optical lenses used in the field of monitoring.

Disclosure of Invention

The present invention is directed to overcoming the above-mentioned drawbacks and deficiencies of the prior art and providing a novel and improved optical lens that enables simultaneous or partial miniaturization, high resolution, low aberrations, low cost and good temperature performance of the lens.

The optical lens has the advantages that the shape of each lens is optimally set and the focal power of each lens is reasonably distributed, so that the miniaturization of the lens is kept, and meanwhile, the high resolving power, the low aberration, the low cost and the good temperature performance are realized.

The optical lens has the advantages that the second lens and the third lens are the cemented lens, so that the sensitivity of the second lens and the third lens can be obviously reduced.

The invention has the advantages that the bearing between the image side surface of the second lens and the object side surface of the third lens can be non-planar bearing through the meniscus lenses of the second lens and the third lens which are glued with each other, so that the assembly inclination tolerance is reduced.

The invention has the advantages that the second lens and the third lens are the cemented lens, so that the fixing piece between the second lens and the third lens can be saved, the assembling parts and the assembling process can be reduced, and the manufacturing cost of the optical lens can be reduced.

An advantage of the present invention is to provide an optical lens that can contribute to miniaturization of the optical lens by the second lens and the third lens being cemented lenses without a gap therebetween.

The invention has the advantage of providing an optical lens, and the imaging performance can be improved through the special shape arrangement of at least one of the second lens and the third lens.

The optical lens has the advantages that the fourth lens is made of a material with a high Abbe number, and the fourth lens is further made of a material with a high refractive index, so that the imaging quality is improved.

The optical lens has the advantages that the fifth lens and the sixth lens are the cemented lens, and the cemented lens is composed of the positive lens and the negative lens, so that the aberration can be effectively corrected, and the resolving power is improved.

The invention has the advantage of providing an optical lens, and the overall length of an optical system can be effectively shortened through the cemented lens of the fifth lens and the sixth lens.

The present invention is advantageous in that it provides an optical lens, which can be miniaturized by setting the focal powers and shapes of the first lens to the sixth lens, and the second lens and the third lens are cemented lenses, and the fifth lens and the sixth lens are cemented lenses.

The optical lens has the advantages that through the use of the two groups of the gluing parts, the optical lens is not only beneficial to correcting aberration and realizing high resolution, but also enables the whole optical system to be compact, meets the miniaturization requirement, and simultaneously reduces the tolerance sensitivity problems of inclination/core deviation and the like generated in the assembling process of the lens unit.

The invention has the advantages that the requirements of high resolving power can be met by adopting the glass spherical lenses from the first lens to the sixth lens and avoiding adopting the non-spherical lenses, and meanwhile, the low cost and the better and stable temperature performance of the optical lens are realized.

An advantage of the present invention is to provide an optical lens that can contribute to an increase in the amount of added light by disposing an aperture stop 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, and the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; 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; the third lens is a meniscus lens with positive focal power, and the object side surface of the third lens is a convex surface and the image side surface of the third lens is a concave surface; 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; the fifth lens is a biconvex lens with positive focal power, and the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; and a sixth lens element which is a meniscus lens element having a negative refractive power, and has a concave object-side surface and a convex image-side surface; wherein the second lens and the third lens are cemented lenses.

In the above optical lens, the fifth lens and the sixth lens are cemented lenses.

In the above optical lens, the second lens satisfies the following conditional expression (1):

0.8≤R21/(R22+D2)≤1.2 (1)

wherein R21 is a central radius of curvature of an object-side surface of the second lens, R22 is a central radius of curvature of an image-side surface of the second lens, and D2 is a central thickness of the second lens.

In the above optical lens, the third lens satisfies the following conditional expression (2):

0.5≤R31/(R32+D3)≤1.1 (2)

wherein R31 is a central radius of curvature of an object-side surface of the third lens, R32 is a central radius of curvature of an image-side surface of the third lens, and D3 is a central thickness of the third lens.

In the above optical lens, the fourth lens satisfies the following conditional expression (3):

V4≥45 (3)

wherein V4 is the abbe number of the material of the fourth lens.

In the above optical lens, the first to sixth lenses satisfy the following conditional expression (4):

TTL/F≤7.5 (4)

wherein F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.

In the above optical lens, the first lens to the sixth lens are all glass lenses.

In the above optical lens, an aperture stop is further included between the third lens and the fourth lens.

The optical lens provided by the invention can realize high resolving power, low aberration, low cost and better temperature performance while keeping the miniaturization of the lens by optimally setting the shapes of all the lenses and reasonably distributing the focal power of all the lenses.

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.

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 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: the first lens is a meniscus lens with negative focal power, and the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; 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; the third lens is a meniscus lens with positive focal power, and the object side surface of the third lens is a convex surface and the image side surface of the third lens is a concave surface; 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; the fifth lens is a biconvex lens with positive focal power, and the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; a sixth lens element having a negative refractive power and a meniscus lens element having a concave object-side surface and a convex image-side surface; wherein the second lens and the third lens are cemented lenses.

In the optical lens according to the embodiment of the invention, the second lens and the third lens are the cemented lens, so that the sensitivities of the second lens and the third lens are reduced remarkably, and the optical lens is beneficial to being assembled in actual production. And because the second lens and the third lens which are glued with each other are meniscus lenses, the bearing between the image side surface of the second lens and the object side surface of the third lens is a non-planar bearing, and the assembly inclination tolerance is reduced. In addition, because the second lens and the third lens are mutually glued, a fixing piece between the second lens and the third lens is saved, thereby reducing assembling components and assembling procedures and reducing the manufacturing cost of the optical lens.

Moreover, the second lens and the third lens are also useful for achieving a small TTL of the optical lens as a whole, i.e., an optical length of the optical lens, which means a distance from the object-side center of the first lens to the imaging focal plane, by being cemented to each other without a gap therebetween.

In addition, preferably, in the optical lens barrel according to the embodiment of the present invention, the fifth lens and the sixth lens are cemented lenses. Moreover, the fifth lens and the sixth lens are combined into the cemented lens similarly to the second lens and the third lens, the sensitivity of the fifth lens and the sensitivity of the sixth lens are obviously reduced by the cemented lens, and the bearing surface between the image side surface of the fifth lens and the object side surface of the sixth lens is non-planar bearing, so that the assembly inclination tolerance is reduced. In addition, a fixing piece between the fifth lens and the sixth lens is saved, so that assembly parts and assembly processes are reduced, the manufacturing cost of the optical lens is reduced, and the small TTL of the whole optical lens is facilitated by the fact that no gap exists between the fifth lens and the sixth lens.

In the optical lens according to the embodiment of the invention, the first lens adopts the meniscus lens which is convex to the object, so that the incident angle of incident light on the attack surface is small, the light in the field of view is collected as much as possible, more light can be collected to enter an optical system, and high incident light quantity is realized. In addition, 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, and the optical lens is beneficial to realizing miniaturization.

In addition, when the lens is applied to the vehicle-mounted lens, the convex surface of the first lens facing the object side is beneficial to being suitable for outdoor use of the vehicle-mounted lens. For example, the convexity may assist in the sliding of water droplets when in an environment such as rainy weather.

The second lens is a divergent lens with a meniscus shape, and can smoothly transit the collected light to the third lens.

The third lens is a convergent lens, so that the divergent light rays passing through the second lens smoothly enter the rear part, and the aperture of the fourth lens is favorably reduced.

In the case that the second lens and the third lens are discrete lenses, the third discrete lens is located at the turning point of the optical path in the optical system, so that the sensitivity is high, and the assembly is not beneficial to actual production. Therefore, by the second lens and the third lens being cemented lenses, the sensitivity of the second lens and the third lens, in particular the tolerance sensitivity with respect to the mechanism fixing parts (e.g. with respect to the lens barrel) can be significantly reduced.

In addition, since the second lens and the third lens are both meniscus lenses, in the case where the second lens and the third lens are discrete lenses, the image-side surface of the second lens and the object-side surface of the third lens are also discrete. Thus, the lens group is supported in a plane, and the inclination sensitivity is higher. And the second lens and the third lens are cemented lenses, so that the assembly tilt tolerance can be remarkably reduced.

Furthermore, the second lens and the third lens are cemented lenses, so that the fixing piece between the second lens and the third lens is saved, the assembling parts are reduced, and the assembling process is simplified, thereby reducing the manufacturing cost of the optical lens. In addition, because the second lens and the third lens are glued with each other, air space is saved, the whole structure of the optical system is compact, the total length of the optical system is favorably shortened, and the miniaturization of the optical lens is realized.

Also, in order to improve imaging performance such as enhancement of resolution and reduction of aberration, the second lens and the third lens preferably have a specific shape setting.

That is, in the optical lens barrel according to the embodiment of the present invention, the second lens satisfies the following conditional expression (1):

0.8≤R21/(R22+D2)≤1.2 (1)

wherein R21 is the central radius of curvature of the object-side surface of the second lens, R22 is the central radius of curvature of the image-side surface of the second lens, and D2 is the central thickness of the second lens.

Also, in an optical lens according to an embodiment of the present invention, the third lens satisfies the following conditional expression (2):

0.5≤R31/(R32+D3)≤1.1 (2)

wherein R31 is a central radius of curvature of an object-side surface of the third lens, R32 is a central radius of curvature of an image-side surface of the third lens, and D3 is a central thickness of the third lens.

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 order to improve imaging performance, it is preferable that the second lens satisfies the above-described conditional expression (1) or the third lens satisfies the above-described expression (2), and it is not necessary that the second lens satisfies the above-described conditional expression (1) and the third lens satisfies the above-described expression (2) at the same time. Of course, if the second lens satisfies the above conditional expression (1) and the third lens satisfies the above expression (2) at the same time, it may further contribute to improving the imaging performance of the optical lens, but the embodiment of the present invention is not limited thereto.

The fourth lens is a biconvex lens, and converges the front light rays and smoothly transits to the rear. Preferably, the fourth lens is made of a material with a high abbe number, and further made of a material with a high refractive index, so that the imaging quality is improved.

That is, in the optical lens barrel according to the embodiment of the present invention, the fourth lens satisfies the following conditional expression (3):

V4≥45 (3)

where V4 is the abbe number of the material of the fourth lens.

In addition, preferably, the optical powers of the fifth lens and the sixth lens are positive, negative. Thus, the fifth lens and the sixth lens are cemented lenses, and the cemented lens is composed of a positive lens and a negative lens, so that aberration can be effectively corrected, and the resolving power can be improved. Meanwhile, the cemented lens of the fifth lens and the sixth lens can also effectively shorten the overall length of the optical system.

Therefore, in the optical lens according to the embodiment of the present invention, the first lens to the sixth lens satisfy the following conditional expression (4):

TTL/F≤7.5 (4)

wherein F is a focal length value of the entire group of the optical lens, and TTL is an optical length of the optical lens, that is, a distance from the object-side center of the first lens to the imaging focal plane.

In this way, by setting the powers and shapes of the first lens to the sixth lens, and the second lens and the third lens being cemented lenses, and the fifth lens and the sixth lens being cemented lenses, miniaturization of the optical lens can be achieved.

That is to say, in the optical lens according to the embodiment of the present invention, the two sets of glue components are used, which is not only beneficial to correcting aberration and realizing high resolution, but also makes the whole optical system compact and meets the miniaturization requirement, and at the same time, reduces the tolerance sensitivity problems of inclination/decentration and the like generated in the assembling process of the lens unit.

In the above optical lens, the first lens to the sixth lens are all glass lenses.

In the above optical lens, the first lens to the sixth lens are all spherical lenses.

Through first lens to sixth lens all adopt glass spherical lens, avoid adopting aspherical lens, can reach the requirement of high resolution power, and realize optical lens's low cost simultaneously to and better stable temperature performance.

Of course, it will be understood by those skilled in the art that glass aspheric lenses may also be used to improve optical performance if cost is not a concern. Alternatively, if cost is a concern, but temperature performance requirements are lower, a plastic aspheric lens may be used to improve optical performance.

Preferably, in the optical lens according to the embodiment of the present invention, the optical lens further includes an aperture stop, which is located between the third lens and the fourth lens, so as to facilitate effective beam-closing of light entering the optical system and reduce the lens aperture of the optical system. Of course, the skilled person will understand that the diaphragm may also be located between any other discrete lenses.

In addition, 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 optical lenses which need to achieve high resolution, low aberration, low cost, and good temperature performance and meet the miniaturization requirement, in addition to the on-board lens and the lens for monitoring. 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. Where 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 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 meniscus-shaped third lens L3 having a positive power, which is a cemented lens with a second transparent L2, having a convex object-side first surface S4 and a concave image-side second surface S5; an aperture stop STO; a biconvex fourth lens L4 having positive optical power, having a first surface S7 convex to the object side and a second surface S8 convex to the image side; a biconvex fifth lens having positive optical power, having a first surface S9 convex to the object side and a second surface S10 convex to the image side; a meniscus-shaped sixth lens L6 having a negative power, which is a cemented lens with the fifth lens L5, is a meniscus-shaped lens having a negative power, and has a first surface S10 concave to the object side and a second surface S11 convex to the image side; a planar lens L7 having a first surface S12 facing the object side and a second surface S13 facing the image side, typically a protective glass and/or a color filter; the image plane L8 has a surface S14, which 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	19.72333	1.1000	1.77	49.6
2	2.7959	1.5000
					3	5.3321	1.3200	1.76	50.6
4	3.5825	1.9893	1.85	23.8
					5	3.0315	0.8290
STO	Infinite number of elements	0.1435
					7	8.5301	3.7000	1.69	54.6
8	-4.1314	0.1000
					9	10.0318	3.8000	1.70	53.6
10	-2.9783	0.5635	1.85	23.8
					11	-9.5819	0.1092
12	Infinite number of elements	0.8922	1.52	64.2
					13	Infinite number of elements	3.4894
IMA	Infinite number of elements

In the optical lens according to the first embodiment of the present invention, the central curvature radius R21 of the object-side surface S3 of the second lens L2, the central curvature radius R22 of the image-side surface S4 of the second lens L2, the central thickness D2 of the second lens L2, and the relationship therebetween, the central curvature radius R31 of the object-side surface S4 of the third lens L3, the central curvature radius R32 of the image-side surface S5 of the third lens L3, the central thickness D3 of the third lens L3, and the relationship therebetween, the abbe number of the material of the fourth lens L4, the entire group focal length value F of the optical lens, and the optical length TTL of the optical lens, and the relationship therebetween are as shown in table 2 below.

[ TABLE 2 ]

R21	5.332
		R22	3.582
D2	1.32
		R21/(R22+D2)	1.088
R31	3.582
		R32	3.032
D3	1.989
		R31/(R32+D3)	0.714
TTL	19.536
		F	2.851
TTL/F	6.853
		V4	54.6

As can be seen from table 2 above, the optical lens according to the first embodiment of the present invention satisfies the aforementioned conditional expressions (1) to (4), thereby achieving high resolving power, low aberration, 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 a negative 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 meniscus-shaped third lens L3 having a positive power, which is a cemented lens with a second transparent L2, having a convex object-side first surface S4 and a concave image-side second surface S5; an aperture stop STO; a biconvex fourth lens L4 having positive optical power, having a first surface S7 convex to the object side and a second surface S8 convex to the image side; a biconvex fifth lens having positive optical power, having a first surface S9 convex to the object side and a second surface S10 convex to the image side; a meniscus-shaped sixth lens L6 having a negative power, which is a cemented lens with the fifth lens L5, is a meniscus-shaped lens having a negative power, and has a first surface S10 concave to the object side and a second surface S11 convex to the image side; a planar lens L7 having a first surface S12 facing the object side and a second surface S13 facing the image side, typically a protective glass and/or a color filter; the image plane L8 has a surface S14, which is typically a chip.

The lens data for the above lenses are shown in table 3 below:

[ TABLE 3 ]

Surface of	Radius of	Thickness of	Nd	Vd
					1	20.09074	1.1000	1.77	49.6
2	2.8310	1.3829
					3	5.4631	1.2915	1.77	49.6
4	3.7000	2.0442	1.90	31.0
					5	3.0959	0.8599
STO	Infinite number of elements	-0.0044
					7	8.7384	3.5000	1.69	54.6
8	-4.1665	0.1000
					9	9.0308	4.2000	1.66	54.6
10	-3.5391	0.6500	1.85	23.8
					11	-9.9140	0.1112
12	Infinite number of elements	0.9089	1.52	64.2
					13	Infinite number of elements	4.2073
IMA	Infinite number of elements

In the optical lens according to the second embodiment of the present invention, the central curvature radius R21 of the object-side surface S3 of the second lens L2, the central curvature radius R22 of the image-side surface S4 of the second lens L2, the central thickness D2 of the second lens L2, and the relationship therebetween, the central curvature radius R31 of the object-side surface S4 of the third lens L3, the central curvature radius R32 of the image-side surface S5 of the third lens L3, the central thickness D3 of the third lens L3, and the relationship therebetween, the abbe number of the material of the fourth lens L4, the entire group focal length value F of the optical lens, and the optical length TTL of the optical lens, and the relationship therebetween are shown in table 4 below.

[ TABLE 4 ]

R21	5.463
		R22	3.700
D2	1.292
		R21/(R22+D2)	1.094
R31	3.700
		R32	3.096
D3	2.045
		R31/(R32+D3)	0.720
TTL	20.352
		F	3.222
TTL/F	6.316
		V4	54.6

As can be seen from table 4 above, the optical lens according to the second embodiment of the present invention satisfies the aforementioned conditional expressions (1) to (4), thereby achieving high resolving power, low aberration, low cost, and good temperature performance while keeping the optical lens compact.

In summary, according to the optical lens of the embodiments of the present invention, by optimally setting the shapes of the respective lenses and reasonably allocating the powers of the respective lenses, high resolution, low aberration, low cost, and good temperature performance can be achieved while keeping the lens compact.

According to the optical lens disclosed by the embodiment of the invention, the second lens and the third lens are the cemented lens, so that the sensitivity of the second lens and the third lens can be obviously reduced.

According to the optical lens disclosed by the embodiment of the invention, the second lens and the third lens which are glued with each other are meniscus lenses, so that the bearing between the image side surface of the second lens and the object side surface of the third lens is a non-planar bearing, and the assembly inclination tolerance is reduced.

According to the optical lens disclosed by the embodiment of the invention, the second lens and the third lens are the cemented lens, so that the fixing piece between the second lens and the third lens can be saved, the assembling parts and the assembling process are reduced, and the manufacturing cost of the optical lens is reduced.

The optical lens according to the embodiment of the present invention can contribute to the miniaturization of the optical lens by the second lens and the third lens being cemented lenses without a gap therebetween.

According to the optical lens disclosed by the embodiment of the invention, the first lens adopts the meniscus shape, so that light rays in a field of view can be collected as far as possible to enter a light ray system, and therefore, high light-entering quantity is realized.

According to the optical lens disclosed by the embodiment of the invention, the first lens adopts the 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, and the optical lens is beneficial to realizing the miniaturization.

According to the optical lens provided by the embodiment of the invention, through the shape and the power setting of the second lens, smooth transition of light rays can be realized, and the aberration generated by the first lens is reduced.

According to the optical lens disclosed by the embodiment of the invention, the third lens is the convergent lens, so that the divergent light rays passing through the second lens can smoothly enter the rear part, and the aperture of the fourth lens is favorably reduced.

The optical lens according to the embodiment of the present invention can improve imaging performance by the special shape setting of at least one of the second lens and the third lens.

According to the optical lens disclosed by the embodiment of the invention, the fourth lens is the convergent lens, so that the front light can be converged and smoothly transited to the rear.

According to the optical lens disclosed by the embodiment of the invention, the fourth lens is made of a material with a high Abbe number, and a material with a high refractive index is further adopted, so that the imaging quality is improved.

According to the optical lens disclosed by the embodiment of the invention, the fifth lens and the sixth lens are the cemented lens, and the cemented lens is composed of the positive lens and the negative lens, so that the aberration can be effectively corrected, and the resolving power is improved.

According to the optical lens of the embodiment of the invention, the whole length of the optical system can be effectively shortened through the cemented lens of the fifth lens and the sixth lens.

The optical lens according to the embodiment of the present invention can realize miniaturization of the optical lens by setting the powers and shapes of the first lens to the sixth lens, and the second lens and the third lens are cemented lenses, and the fifth lens and the sixth lens are cemented lenses.

According to the optical lens disclosed by the embodiment of the invention, through the use of the two groups of the gluing parts, the aberration is favorably corrected, the high resolution is realized, the whole optical system is compact, the miniaturization requirement is met, and meanwhile, the tolerance sensitivity problems of inclination/core deviation and the like generated in the assembling process of the lens unit are reduced.

According to the optical lens disclosed by the embodiment of the invention, the first lens, the second lens, the third lens and the fourth lens are glass spherical lenses, so that the adoption of aspheric lenses is avoided, the requirement of high resolving power can be met, and meanwhile, the low cost and the good and stable temperature performance of the optical lens are realized.

According to the optical lens disclosed by the embodiment of the invention, the first lens, the second lens, the third lens and the fourth lens are glass aspheric lenses, so that the optical performance can be improved.

According to the optical lens disclosed by the embodiment of the invention, the plastic aspheric lenses are adopted from the first lens to the sixth lens, so that the low cost and the improvement on the optical performance can be realized under the condition of lower temperature performance requirement.

The optical lens according to the embodiment of the present invention can contribute to an increase in the amount of added light by disposing the aperture stop between the third lens and the fourth lens.

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 sixth lenses.

As described above, the optical lens according to the embodiment of the present invention can be applied to any optical lens that needs to achieve high resolving power, low aberration, low cost, and good temperature performance while keeping the lens compact, 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 an imaging apparatus, for example, as an optical lens for a vehicle or a monitoring apparatus, and the embodiment of the present invention is not intended to limit it 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.

Claims (10)

1. An optical lens in which the number of lenses having optical power is six, which are:

the first lens is a meniscus lens with negative focal power, and the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;

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;

the third lens is a meniscus lens with positive focal power, and the object side surface of the third lens is a convex surface and the image side surface of the third lens is a concave surface;

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;

the fifth lens is a biconvex lens with positive focal power, and the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; and

a sixth lens element having a negative refractive power and a meniscus lens element having a concave object-side surface and a convex image-side surface;

the first lens to the sixth lens are arranged in order from an object side to an image side;

wherein the second lens and the third lens constitute a cemented lens; and

wherein the second lens satisfies the following conditional expression (1):

0.8≤R21/(R22+D2)≤1.2 (1)

wherein R21 is a central radius of curvature of an object-side surface of the second lens, R22 is a central radius of curvature of an image-side surface of the second lens, and D2 is a central thickness of the second lens.

2. An optical lens according to claim 1, characterized in that the fifth lens and the sixth lens constitute a cemented lens.

3. An optical lens according to claim 2, wherein the third lens satisfies the following conditional expression (2):

0.5≤R31/(R32+D3)≤1.1 (2)

wherein R31 is a central radius of curvature of an object-side surface of the third lens, R32 is a central radius of curvature of an image-side surface of the third lens, and D3 is a central thickness of the third lens.

4. An optical lens according to claim 2, wherein the fourth lens satisfies the following conditional expression (3):

V4≥45 (3)

wherein V4 is the abbe number of the material of the fourth lens.

5. The optical lens according to claim 2, characterized in that the first to sixth lenses satisfy the following conditional expression (4):

TTL/F≤7.5 (4)

wherein F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.

6. An optical lens according to claim 1, wherein the third lens satisfies the following conditional expression (2):

0.5≤R31/(R32+D3)≤1.1 (2)

wherein R31 is a central radius of curvature of an object-side surface of the third lens, R32 is a central radius of curvature of an image-side surface of the third lens, and D3 is a central thickness of the third lens.

7. An optical lens according to claim 1, wherein the fourth lens satisfies the following conditional expression (3):

V4≥45 (3)

wherein V4 is the abbe number of the material of the fourth lens.

8. An optical lens according to claim 1, wherein the first to sixth lenses satisfy the following conditional expression (4):

TTL/F≤7.5 (4)

wherein F is the whole group focal length value of the optical lens, and TTL is the optical length of the optical lens.

9. An optical lens barrel according to any one of claims 1 to 8, wherein the first lens to the sixth lens are all glass lenses.

10. An optical lens according to any one of claims 1 to 8, further comprising an aperture stop between the third lens and the fourth lens.

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