阅读说明：本技术 光学镜头 (Optical lens ) 是由 栾晓宇 王东方 姚波 于 2018-07-27 设计创作，主要内容包括：本申请公开了一种光学镜头,该光学镜头沿着光轴由物侧至像侧依序可包括：第一透镜、第二透镜、第三透镜、第四透镜、第五透镜、第六透镜和第七透镜。其中,第一透镜可具有负光焦度,其物侧面为凸面,像侧面为凹面；第二透镜可具有负光焦度,其像侧面为凹面；第三透镜可具有负光焦度,其物侧面为凹面,像侧面为凸面；第四透镜可具有正光焦度,其物侧面和像侧面均为凸面；第五透镜可具有负光焦度,其物侧面为凸面,像侧面为凹面；第六透镜可具有正光焦度,其物侧面和像侧面均为凸面；以及第七透镜可具有正光焦度,其物侧面为凸面。根据本申请的光学镜头,可实现小型化、前端小口径、高解像、超大视场角等有益效果中的至少一个。(The present application discloses an optical lens, which sequentially comprises, from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens can have 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 can have negative focal power, and the image side surface of the second lens is a concave surface; the third lens can have negative focal power, and the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; the fourth lens can have positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces; the fifth lens element has negative focal power, and has a convex object-side surface and a concave image-side surface; the sixth lens element can have a positive focal power, and both the object-side surface and the image-side surface of the sixth lens element are convex; and the seventh lens may have positive optical power with a convex object-side surface. According to the optical lens, at least one of the beneficial effects of miniaturization, small front-end caliber, high resolution, ultra-large field angle and the like can be realized.)

1. The optical lens sequentially comprises from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens,

it is characterized in that the preparation method is characterized in that,

the first lens has negative focal power, 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 has negative focal power, and the image side surface of the second lens is a concave surface;

the third lens has negative focal power, the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface;

the fourth lens has positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces;

the fifth lens has negative focal power, the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface;

the sixth lens has positive focal power, and both the object side surface and the image side surface of the sixth lens are convex surfaces; and

the seventh lens has positive focal power, and the object side surface of the seventh lens is a convex surface.

2. An optical lens according to claim 1, wherein the fifth lens and the sixth lens are cemented to each other to form a cemented lens.

3. An optical lens barrel according to claim 1, wherein the object side surface of the second lens is convex.

4. An optical lens barrel according to claim 1, wherein the object side surface of the second lens is concave.

5. An optical lens barrel according to claim 1, wherein the image side surface of the seventh lens element is convex.

6. An optical lens barrel according to claim 1, wherein the image side surface of the seventh lens element is concave.

7. An optical lens according to claim 1, characterized in that the optical lens has at least 4 aspherical lenses.

8. An optical lens according to claim 7, wherein the second lens, the third lens and the seventh lens are all aspherical lenses.

9. An optical lens according to any one of claims 1 to 8, characterized in that the conditional expression is satisfied: d12/TTL is less than or equal to 0.2,

wherein d12 is the air space between the first lens and the second lens; and

TTL is a distance on the optical axis from the center of the object-side surface of the first lens element to the imaging surface of the optical lens.

10. An optical lens according to any one of claims 1 to 8, wherein the maximum field angle FOV of the optical lens, the entire set of focal length values F of the optical lens and the image height h corresponding to the maximum field angle of the optical lens satisfy: (FOV multiplied by F)/h is more than or equal to 45.

11. An optical lens as claimed in any one of claims 1 to 8, characterized in that the refractive index of the material of the first lens is 1.65 or higher.

12. An optical lens according to any one of claims 1 to 8, wherein the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens satisfy: D/h/FOV is less than or equal to 0.02.

13. An optical lens barrel according to any one of claims 1 to 8, wherein a distance TTL between a center of an object side surface of the first lens element and an image plane of the optical lens on the optical axis, and a distance BFL between a center of an image side surface of the seventh lens element and the image plane of the optical lens on the optical axis, satisfy BFL/TTL ≧ 0.1.

14. An optical lens barrel according to any one of claims 1 to 8, wherein a distance TTL between a center of an object side surface of the first lens and an imaging surface of the optical lens on the optical axis, a maximum field angle FOV of the optical lens, and an image height h corresponding to the maximum field angle of the optical lens satisfy: TTL/h/FOV is less than or equal to 0.025.

15. The optical lens sequentially comprises from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens,

it is characterized in that the preparation method is characterized in that,

the first lens, the second lens, the third lens and the fifth lens each have a negative optical power;

the fourth lens, the sixth lens and the seventh lens each have positive optical power;

the fifth lens is glued with the sixth lens; and

the maximum field angle FOV of the optical lens, the whole group of focal length values F of the optical lens and the image height h corresponding to the maximum field angle of the optical lens satisfy the following conditions: (FOV multiplied by F)/h is more than or equal to 45.

Technical Field

The present application relates to an optical lens, and more particularly, to an optical lens including seven lenses.

Background

With the popularization of optical lenses, the requirements for high definition and image comfort of images of vehicle-mounted lenses are increasingly highlighted in the market. At present, in order to achieve a resolution of mega pixels, an aspheric surface is usually used to correct aberrations including chromatic aberration, and a high resolution is obtained by increasing the number of lenses to more than 6, but the size and weight of the lens are correspondingly increased, which is not favorable for miniaturization of the lens, and causes a cost increase.

At present, the plastic lens is mostly adopted to achieve the effects of reducing cost and lightening weight, however, the plasticizing degree is high, because the expansion and contraction characteristics of the plastic lens are difficult to overcome, although the temperature performance is better realized through the collocation of the focal power of the lens and the selection of materials, the whole body still can not meet the existing severer temperature requirement. Of course, the imaging quality can be improved by adopting the glass aspheric lens, and the temperature performance requirement is met, but the glass aspheric manufacturing process is difficult, and the cost is high.

Therefore, for a lens, such as a monitoring lens or a vehicle-mounted lens, which operates in a variable and severe environment and has a limited installation space, the requirements for further improving miniaturization and high resolution are more urgent and severe.

Disclosure of Invention

The present application provides an optical lens that is adaptable for on-board installation and that overcomes, at least in part, at least one of the above-identified deficiencies in the prior art.

An aspect of the present application provides an optical lens that may include, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens can have 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 can have negative focal power, and the image side surface of the second lens is a concave surface; the third lens can have negative focal power, and the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; the fourth lens can have positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces; the fifth lens element has negative focal power, and has a convex object-side surface and a concave image-side surface; the sixth lens element can have a positive focal power, and both the object-side surface and the image-side surface of the sixth lens element are convex; and the seventh lens may have positive optical power with a convex object-side surface.

In one embodiment, the fifth lens and the sixth lens may be cemented with each other to form a cemented lens.

In one embodiment, the object side surface of the second lens can be convex.

In another embodiment, the object side surface of the second lens can be concave.

In one embodiment, the image-side surface of the seventh lens element may be convex.

In another embodiment, the image-side surface of the seventh lens element may be concave.

In one embodiment, the optical lens may have at least 4 aspheric lenses.

In one embodiment, the second lens, the third lens, and the seventh lens may each be an aspheric lens.

In one embodiment, the conditional formula may be satisfied: d12/TTL is less than or equal to 0.2, wherein d12 is the air space between the first lens and the second lens; and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis.

In one embodiment, the maximum field angle FOV of the optical lens, the entire set of focal length values F of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens may satisfy: (FOV multiplied by F)/h is more than or equal to 45.

In one embodiment, the refractive index of the material of the first lens may be 1.65 or more.

In one embodiment, the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens may satisfy: D/h/FOV is less than or equal to 0.02.

In one embodiment, a distance between a center of an object side surface of the first lens element and an imaging surface of the optical lens on an optical axis TTL and a distance between a center of an image side surface of the seventh lens element and the imaging surface of the optical lens on the optical axis BFL may satisfy BFL/TTL ≧ 0.1.

In one embodiment, a distance TTL from a center of an object-side surface of the first lens to an imaging surface of the optical lens on the optical axis, a maximum field angle FOV of the optical lens, and an image height h corresponding to the maximum field angle of the optical lens may satisfy: TTL/h/FOV is less than or equal to 0.025.

Another aspect of the present application provides an optical lens that may include, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens, the second lens, the third lens and the fifth lens all have negative focal power; the fourth lens, the sixth lens and the seventh lens may each have positive optical power; the fifth lens may be cemented with the sixth lens; and the maximum field angle FOV of the optical lens, the whole group of focal length values F of the optical lens and the image height h corresponding to the maximum field angle of the optical lens can satisfy the following conditions: (FOV multiplied by F)/h is more than or equal to 45.

In one embodiment, the object-side surface of the first lens element can be convex and the image-side surface can be concave.

In one embodiment, the object-side surface of the second lens element can be convex and the image-side surface can be concave.

In another embodiment, both the object-side surface and the image-side surface of the second lens can be concave.

In one embodiment, the object-side surface of the third lens element can be concave and the image-side surface can be convex.

In one embodiment, both the object-side surface and the image-side surface of the fourth lens can be convex.

In one embodiment, the object-side surface of the fifth lens element can be convex and the image-side surface can be concave.

In one embodiment, both the object-side surface and the image-side surface of the sixth lens element can be convex.

In one embodiment, both the object-side surface and the image-side surface of the seventh lens element can be convex.

In another embodiment, the object-side surface of the seventh lens element can be convex and the image-side surface can be concave.

In one embodiment, the optical lens may have at least 4 aspheric lenses.

In one embodiment, the second lens, the third lens, and the seventh lens may each be an aspheric lens.

In one embodiment, the conditional formula may be satisfied: d12/TTL is less than or equal to 0.2, wherein d12 is the air space between the first lens and the second lens; and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis.

In one embodiment, the refractive index of the material of the first lens may be 1.65 or more.

In one embodiment, the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens may satisfy: D/h/FOV is less than or equal to 0.02.

In one embodiment, a distance between a center of an object side surface of the first lens element and an imaging surface of the optical lens on an optical axis TTL and a distance between a center of an image side surface of the seventh lens element and the imaging surface of the optical lens on the optical axis BFL may satisfy BFL/TTL ≧ 0.1.

In one embodiment, a distance TTL from a center of an object-side surface of the first lens to an imaging surface of the optical lens on the optical axis, a maximum field angle FOV of the optical lens, and an image height h corresponding to the maximum field angle of the optical lens may satisfy: TTL/h/FOV is less than or equal to 0.025.

The optical lens adopts seven lenses, the focal power of each lens is reasonably distributed and the cemented lens is formed by optimally setting the shape of the lens, so that at least one of the beneficial effects of small caliber, high pixel, miniaturization, super-large field angle and the like at the front end of the optical lens is realized.

Drawings

Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments when taken in conjunction with the accompanying drawings. In the drawings:

fig. 1 is a schematic view showing a structure of an optical lens according to embodiment 1 of the present application;

fig. 2 is a schematic structural view showing an optical lens according to embodiment 2 of the present application; and

fig. 3 is a schematic view showing a structure of an optical lens according to embodiment 3 of the present application.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens, and the first cemented lens may also be referred to as the second cemented lens, without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side surface, and the surface of each lens closest to the image plane is called the image side surface.

It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

The features, principles, and other aspects of the present application are described in detail below.

An optical lens according to an exemplary embodiment of the present application includes, for example, seven lenses having optical power, i.e., a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The seven lenses are arranged in order from the object side to the image side along the optical axis.

The optical lens according to the exemplary embodiment of the present application may further include a photosensitive element disposed on the image plane. Alternatively, the photosensitive element provided to the imaging surface may be a photosensitive coupling element (CCD) or a complementary metal oxide semiconductor element (CMOS).

The first lens element can have a negative power, and can have a convex object-side surface and a concave image-side surface. The first lens is arranged in a meniscus shape which is convex towards the object side, so that light rays with a large field of view can be collected as far as possible and enter a rear optical system. In practical application, the vehicle-mounted lens is installed outdoors in a use environment and can be in severe weather such as rain, snow and the like, and the design of the meniscus shape protruding towards the object side is beneficial to the sliding of water drops and reduces the influence on imaging. Alternatively, the first lens can be made of a high-refractive-index material, such as the refractive index Nd1 ≥ 1.65, ideally Nd1 ≥ 1.7, so as to facilitate reducing the front-end aperture and improving the imaging quality.

The second lens element can have a negative power, and can have an object-side surface that is optionally convex or concave, and an image-side surface that is concave. The second lens can properly compress the light collected by the first lens, so that the light can be smoothly transited to a rear optical system. The image side surface of the second lens is a concave surface, so that the distance between the first lens and the second lens is favorably reduced, the physical total length of the lens is easier to shorten, and the miniaturization is realized.

The third lens element can have a negative power, and can have a concave object-side surface and a convex image-side surface. The third lens with negative focal power can balance the spherical aberration and the position chromatic aberration introduced by the first two groups of lenses, and the meniscus shape convex to the image side is designed, so that the total length of the optical system is favorably reduced.

The fourth lens element can have a positive optical power, and can have a convex object-side surface and a convex image-side surface. The fourth lens can converge the light, so that the diffused light can smoothly enter the rear optical system, and the light is compressed and stably transited to the rear optical system.

The fifth lens element can have a negative power, and can have a convex object-side surface and a concave image-side surface.

The sixth lens element can have a positive optical power, and can have a convex object-side surface and a convex image-side surface.

The seventh lens element can have a positive optical power, and can have a convex object-side surface and a convex or concave image-side surface. The seventh lens is a converging lens, so that light can be converged effectively and stably at last, the light can reach an imaging surface stably, and the overall weight and cost of the optical system are reduced.

In an exemplary embodiment, a stop for limiting the light beam may be disposed between, for example, the fourth lens and the fifth lens to further improve the imaging quality of the lens. When the diaphragm is arranged between the fourth lens and the fifth lens, the front light and the rear light can be collected, the total length of the optical system is effectively shortened, and the calibers of the front lens and the rear lens are reduced. It should be noted, however, that the positions of the diaphragms disclosed herein are merely examples and not limitations; in alternative embodiments, the diaphragm may be disposed at other positions according to actual needs.

In an exemplary embodiment, the optical lens according to the present application may further include a filter disposed between the seventh lens and the imaging surface to filter light rays having different wavelengths, as necessary; and may further include a protective glass disposed between the optical filter and the imaging surface to prevent internal elements (e.g., chips) of the optical lens from being damaged.

As known to those skilled in the art, cemented lenses may be used to minimize or eliminate chromatic aberration. The use of the cemented lens in the optical lens can improve the image quality and reduce the reflection loss of light energy, thereby improving the imaging definition of the lens. In addition, the use of the cemented lens can also simplify the assembly process in the lens manufacturing process.

In an exemplary embodiment, the fifth lens and the sixth lens may be combined into a cemented lens by cementing the image-side surface of the fifth lens with the object-side surface of the sixth lens. By introducing the cemented lens consisting of the fifth lens and the sixth lens, the chromatic aberration influence can be eliminated, the field curvature is reduced, and the coma is corrected; meanwhile, the cemented lens may also retain a part of chromatic aberration to balance the entire chromatic aberration of the optical system. The air space between the two lenses is omitted by gluing the lenses, so that the optical system is compact as a whole, and the requirement of system miniaturization is met. Furthermore, the gluing of the lenses reduces tolerance sensitivity problems of the lens units due to tilt/decentration during assembly.

In the cemented lens, the fifth lens close to the object side has negative focal power, and the sixth lens close to the image side has positive focal power, so that the arrangement is favorable for diverging and rapidly converging the front light and then transitioning to the rear, is more favorable for reducing the optical path of the rear light, realizes short TTL, and simultaneously reduces the tolerance sensitivity of the system.

In an exemplary embodiment, an air interval d12 between the first lens and the second lens and an optical total length TTL of the optical lens may satisfy: d12/TTL is less than or equal to 0.2, and more preferably, d12/TTL is less than or equal to 0.18.

In an exemplary embodiment, the maximum field angle FOV of the optical lens, the entire set of focal length values F of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens may satisfy: (FOV F)/h.gtoreq.45, and more preferably (FOV F)/h.gtoreq.50. The condition (FOV multiplied by F)/h is more than or equal to 45, and the large-angle resolution can be realized.

In an exemplary embodiment, the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens may satisfy: D/h/FOV is less than or equal to 0.02, and more desirably, D/h/FOV is less than or equal to 0.018. The conditional expression D/h/FOV is less than or equal to 0.02, and the small caliber at the front end of the lens can be realized.

In an exemplary embodiment, the optical back focus BFL of the optical lens and the total optical length TTL of the optical lens may satisfy: the BFL/TTL is more than or equal to 0.1, and more ideally, the BFL/TTL can be further more than or equal to 0.11. The back focus setting which meets the condition that BFL/TTL is more than or equal to 0.1 is combined with the whole framework of the optical lens, so that the assembly of an optical system can be facilitated.

In an exemplary embodiment, the total optical length TTL of the optical lens, the maximum field angle FOV of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens may satisfy: TTL/h/FOV is less than or equal to 0.025, and more preferably, TTL/h/FOV is less than or equal to 0.02. The TTL/h/FOV satisfies the conditional expression of being less than or equal to 0.025, miniaturization can be realized, and compared with other lenses, the TTL is shorter under the same field angle and the same image height.

In an exemplary embodiment, an optical lens according to the present application may have at least 4 aspherical lenses. The aspheric lens has the characteristics that: the curvature varies continuously from the center of the lens to the periphery. Unlike a spherical lens having a constant curvature from the center to the periphery of the lens, an aspherical lens has better curvature radius characteristics, and has the advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated in imaging can be eliminated as much as possible, so that the imaging quality of the lens is improved. For example, the seventh lens element may be an aspheric lens element to reduce the optical path length of the peripheral light rays to the image plane, and at the same time, correct the off-axis point aberration of the system, and optimize the optical performance such as distortion and CRA. Ideally, the second lens, the third lens and the seventh lens are all aspheric lenses so as to effectively improve the imaging quality of the lens. In addition, one or more of the first lens, the fifth lens and the sixth lens can also adopt an aspheric lens to improve the imaging quality. It is understood that the optical lens according to the present application may increase the number of aspherical lenses in order to improve the imaging quality.

In an exemplary embodiment, the lens used in the optical lens may be a plastic lens, or may be a glass lens. The lens made of plastic has a large thermal expansion coefficient, and when the ambient temperature change of the lens is large, the lens made of plastic causes a large amount of change of the optical back focus of the lens. The glass lens can reduce the influence of temperature on the optical back focus of the lens. According to the optical lens's of this application first lens can adopt the glass lens to reduce the environment and to the holistic influence of system, promote optical lens's wholeness ability. Ideally, the first lens can adopt a glass aspheric lens to further improve the imaging quality and reduce the front end aperture.

According to the optical lens of the embodiment of the application, the shape of the lens is optimally set, the focal power is reasonably distributed, the lens material is reasonably selected, the front end aperture can be reduced, the TTL is shortened, the miniaturization of the lens is ensured, and meanwhile, the characteristics of high resolution and super-large field angle are realized; in addition, the lens according to the application adopts 7 lenses, more than four million pixels can be achieved, and higher definition can be realized; the lens has a longer focal length compared with a conventional wide-angle lens, and the central area has high-angle resolution, so that the identification degree of an environmental object can be improved, and the detection area of the central part is increased in a targeted manner; this application is through setting up the position of positive and negative lens of cemented lens, effectively must reduce tolerance sensitivity. The optical lens according to the above-described embodiment of the present application can better meet the requirements of an in-vehicle lens.

However, it will be appreciated by those skilled in the art that the number of lenses constituting the lens barrel may be varied to achieve the various results and advantages described in the present specification without departing from the claimed subject matter. For example, although seven lenses are exemplified in the embodiment, the optical lens is not limited to include seven lenses. The optical lens may also include other numbers of lenses, if desired.

Specific examples of an optical lens applicable to the above-described embodiments are further described below with reference to the drawings.