CN109975950B

CN109975950B - Optical lens

Info

Publication number: CN109975950B
Application number: CN201711446517.3A
Authority: CN
Inventors: 周召涛; 郎海涛; 史张锦; 樊坚; 杨佳
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2017-12-27
Filing date: 2017-12-27
Publication date: 2021-06-04
Anticipated expiration: 2037-12-27
Also published as: CN109975950A

Abstract

The application discloses optical lens, this optical lens can include from the front end to the rear end according to the preface: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens can have positive focal power, the front side surface of the first lens is a convex surface, and the back side surface of the first lens is a concave surface; the second lens can have negative focal power, the front side surface of the second lens is a convex surface, and the back side surface of the second lens is a concave surface; the third lens element may have a negative focal power, and both the front side surface and the back side surface thereof are concave surfaces; the fourth lens can have positive focal power, and both the front side surface and the back side surface of the fourth lens are convex surfaces; the fifth lens can have positive focal power, and the back side surface of the fifth lens is a convex surface; the sixth lens element may have a positive optical power, and both the front side surface and the rear side surface thereof are convex surfaces; and the third lens may be cemented with the fourth lens. According to the optical lens of the present application, effects such as miniaturization and back focal length can be achieved.

Description

Optical lens

Technical Field

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

Background

With the development of the technology, more and more fields need to be applied to the lens, and at present, the lens is generally required to have good imaging quality in some application fields, and meanwhile, the lens is required to have small volume and strong stability, can normally work in a larger temperature range, and is required to have focal length behind the lens in some application fields. Such as vehicle lenses, projection lenses, etc.

For example, since the vehicle needs to be used outdoors, the performance stability of the lens in various temperature environments is particularly important. And the lens needs to meet the miniaturization requirement due to the limitation of the installation space in the vehicle. The requirement of high resolution is essential, and the back focal length is favorable for the assembly of the lens or other application requirements.

Such as a vehicle-mounted HUD projection lens, the important role of the vehicle-mounted HUD in driving safety has been widely popularized. However, the conventional HUD has short projection distance, large volume and small projection imaging area, which seriously hinders the further application and development of HUD. Simultaneously on-vehicle HUD projecting lens installs inside the car, because the inside temperature variation of automobile body is great, this imaging stability to projecting lens in great difference in temperature within range has also provided high requirement.

For example, a projection lens generates heat seriously when a projection device works for a long time, so that the performance stability of the lens at various temperatures is important, and meanwhile, along with the requirements of portable and miniaturized projectors, the miniaturization of the projection lens is also an inevitable trend, and the longer back focus of the lens has better compatibility with some projection fields needing to be matched with an illumination system.

Accordingly, the present application provides an optical lens that is miniaturized, has a back focal length, and can be applied to, for example, an in-vehicle lens, a projection lens, and the like.

Disclosure of Invention

The present application provides an optical lens that may overcome at least or partially overcome at least one of the above-mentioned deficiencies in the prior art.

An aspect of the present application provides an optical lens that may include, in order from a front end to a rear end: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens can have positive focal power, the front side surface of the first lens is a convex surface, and the back side surface of the first lens is a concave surface; the second lens can have negative focal power, the front side surface of the second lens is a convex surface, and the back side surface of the second lens is a concave surface; the third lens element may have a negative focal power, and both the front side surface and the back side surface thereof are concave surfaces; the fourth lens can have positive focal power, and both the front side surface and the back side surface of the fourth lens are convex surfaces; the fifth lens can have positive focal power, and the back side surface of the fifth lens is a convex surface; the sixth lens element may have a positive optical power, and both the front side surface and the rear side surface thereof are convex surfaces; and the third lens may be cemented with the fourth lens.

In one embodiment, the front side of the fifth lens may be concave.

In another embodiment, the front side of the fifth lens may be planar.

In yet another embodiment, the front side of the fifth lens may be convex. Further, a radius of curvature R9 of the front side of the fifth lens and a radius of curvature R10 of the rear side of the fifth lens may satisfy: R9/R10 is not less than-1.6 and not more than-0.5.

In one embodiment, the total optical length TTL of the optical lens and the entire group focal length F of the optical lens may satisfy: TTL/F is less than or equal to 4.

In one embodiment, the optical back focal length BFL of the optical lens and the entire set of focal length values F of the optical lens may satisfy: BFL/F is more than or equal to 0.6.

In one embodiment, the radius of curvature R3 of the front side of the second lens, the radius of curvature R4 of the back side of the second lens, and the thickness d3 of the second lens may satisfy: R3/(R4+ d3) is more than or equal to 0.6 and less than or equal to 1.5.

In one embodiment, the focal length value F1 of the first lens and the focal length value F2 of the second lens satisfy: f1 of-3 is less than or equal to that of F2 is less than or equal to-0.4.

In one embodiment, the combined focal length value F34 of the third lens and the fourth lens and the entire set of focal length values F of the optical lens may satisfy: F34/F is more than or equal to 2 and less than or equal to 8.

In one embodiment, a combined focal length value F56 of the fifth lens and the sixth lens and a whole set focal length value F of the optical lens may satisfy: F56/F is more than or equal to 0.5 and less than or equal to 1.3.

In one embodiment, a radius of curvature R11 of the sixth lens front side surface and a radius of curvature R12 of the sixth lens rear side surface may satisfy: R11/R12 is not less than-1.4 and not more than-0.6.

Another aspect of the present application provides an optical lens that may include, in order from a front end to a rear end: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. Wherein the first lens, the fourth lens, the fifth lens and the sixth lens have positive focal power; the second lens and the third lens have negative focal power; the front side surfaces of the first lens and the second lens are convex surfaces, and the rear side surfaces of the first lens and the second lens are concave surfaces; the front side and the back side of the fourth lens and the sixth lens are convex surfaces; and the total optical length TTL of the optical lens and the whole group of focal length values F of the optical lens meet the following conditions: TTL/F is less than or equal to 4.

In one embodiment, the front side surface of the fifth lens element can be concave and the back side surface can be convex.

In another embodiment, the front side of the fifth lens element can be planar and the back side can be convex.

In yet another embodiment, both the front and back sides of the fifth lens can be convex. Further, a radius of curvature R9 of the front side of the fifth lens and a radius of curvature R10 of the rear side of the fifth lens may satisfy: R9/R10 is not less than-1.6 and not more than-0.5.

In one embodiment, both the anterior and posterior sides of the third lens can be concave.

In one embodiment, the third lens may be cemented with the fourth lens.

The optical lens adopts six lenses, the focal power of each lens is reasonably distributed and the cemented lens is formed by optimally setting the shape of the lens, and the beneficial effects of miniaturization, back focal length, wide application and the like of the optical lens are 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. It should be understood that the surface of each lens near the front end is referred to as the front side surface, the surface of each lens near the back end is referred to as the back side surface, and each lens may have a front side surface and a back 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, six lenses having optical power, i.e., a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The six lenses are arranged in order from the front end to the rear end.

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 positive optical power, and the front side surface can be convex and the back side surface can be concave. It is advantageous that the first lens is arranged in a meniscus shape convex towards the front side. For example, when used as a projection lens, the meniscus shape toward the magnification end (image side) can ensure as large a projection angle as possible; when the lens is used as a vehicle-mounted lens, the design of the crescent shape protruding to the front side can collect light rays with large angles as much as possible, so that the light rays enter a rear optical system. In practical application, the vehicle-mounted lens is installed outdoors and used in an environment, and can be in severe weather such as rain, snow and the like, and the design of the shape of the meniscus protruding towards the front side is beneficial to the sliding of water drops and reduces the influence on imaging.

The second lens element can have a negative power, and the front side surface can be convex and the back side surface can be concave. The second lens can smooth the light trend and correct the system aberration. Wherein, the second lens can be configured to be a special design of approximate concentric circles, namely, the curvature radius R3 of the front side surface of the second lens, the curvature radius R4 of the back side surface of the second lens and the thickness d3 of the second lens can satisfy: R3/(R4+ d3) is 0.6. ltoreq.1.5, and preferably 1.1. ltoreq.R 3/(R4+ d3) is 1.3. By the configuration, spherical aberration can be reduced, and the image quality of the system is improved.

The third lens may have a negative optical power, and both the front side and the back side may be concave.

The fourth lens may have a positive optical power, and both the anterior and posterior sides thereof may be convex.

The fifth lens may have a positive optical power with an optionally convex, planar or concave front side and a convex back side. The fifth lens is a convergent lens, so that the light divergence angle can be further compressed, and the caliber of the lens is reduced. The fifth lens can be made of low-dispersion materials, and chromatic aberration of the system can be compensated. In an exemplary embodiment, when the fifth lens element is configured as a biconvex positive lens element, a radius of curvature R9 of the front side surface of the fifth lens element and a radius of curvature R10 of the rear side surface of the fifth lens element may satisfy-1.6. ltoreq. R9/R10. ltoreq. 0.5, and desirably, may further satisfy-1.2. ltoreq. R9/R10. ltoreq. 0.8. Such a configuration can be beneficial for improving image quality and controlling aberration.

The sixth lens may have a positive optical power, and both the front side and the back side may be convex. The sixth lens is a converging lens, so that light rays are converged and then enter the rear optical system.

In an exemplary embodiment, the first to sixth lenses may each employ a spherical lens.

In an exemplary embodiment, a stop for limiting the light beam, for example, disposed between the second lens and the third lens, may be further included in the optical lens. It should be understood that the diaphragm can be disposed in any position of the lens as required, according to the application/requirement, without being limited by the above-mentioned position.

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 third lens and the fourth lens may be combined into a cemented lens by cementing a back side of the third lens with a front side of the fourth lens. By introducing the cemented lens consisting of the third lens and the fourth 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 third lens has negative focal power, and the fourth lens has positive focal power, so that the arrangement can form a symmetrical structure relative to the diaphragm with the first lens and the second lens, which is beneficial to reducing the drift of the back focus along with the change of the ambient temperature and balancing the system aberration.

In an exemplary embodiment, TTL/F ≦ 4 may be satisfied between the total optical length TTL of the optical lens and the entire set of focal length values F of the optical lens, and ideally, TTL and F may further satisfy TTL/F ≦ 3. The condition TTL/F is less than or equal to 4, and the miniaturization characteristic of the lens can be realized.

In an exemplary embodiment, the optical back focal length BFL of the optical lens and the entire set of focal length values F of the optical lens may satisfy: the BFL/F is more than or equal to 0.6, ideally, the BFL/F can be further more than or equal to 0.8. Satisfies the conditional expression BFL/F is more than or equal to 0.6, and can realize the back focal length characteristic of the lens

In an exemplary embodiment, a focal length value F1 of the first lens and a focal length value F2 of the second lens may satisfy-3. ltoreq. F1/F2. ltoreq.0.4, and desirably, may further satisfy-2.1. ltoreq. F1/F2. ltoreq.1.8. Through the reasonable distribution of the focal power of the first lens and the second lens, the spherical aberration of the system can be balanced, and the image quality is improved.

In the exemplary embodiment, 2 ≦ F34/F ≦ 8 may be satisfied between the combined focal length value F34 of the third lens and the fourth lens and the entire group focal length value F of the optical lens, and ideally, 4 ≦ F34/F ≦ 6 may be further satisfied. Through reasonable focal power distribution, the temperature stability of the lens can be favorably improved.

In the exemplary embodiment, 0.5 ≦ F56/F ≦ 1.3 may be satisfied between the combined focal length value F56 of the fifth lens and the sixth lens and the entire group focal length value F of the optical lens, and ideally, 0.8 ≦ F56/F ≦ 1 may be further satisfied. Through reasonable focal power distribution, the temperature stability of the lens can be favorably improved.

In an exemplary embodiment, a radius of curvature R11 of the front side surface of the sixth lens and a radius of curvature R12 of the rear side surface of the sixth lens may satisfy-1.4. ltoreq. R11/R12. ltoreq.0.6, and desirably, may further satisfy-1.2. ltoreq. R11/R12. ltoreq.0.8. The shape design is beneficial to improving the image quality of the system and controlling the aberration.

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 has a large influence on the overall performance of the lens. The glass lens can reduce the influence of temperature on the performance of the lens, but has higher cost.

Through reasonable lens shape setting, lens arrangement, distribution of focal power of each optical surface and reasonable matching of materials of each lens, the imaging lens has excellent imaging effect/projection quality, such as higher resolving power, small chromatic aberration and distortion control within +/-1%; the length of the lens is greatly reduced while the imaging quality is ensured, and the length of the lens is controlled within 35mm, so that the lens is convenient to mount in a limited space; the lens has a longer back focus, so that the back end of the lens has enough space for placing other elements, and the interference of a mechanism is avoided; and can keep good imaging effect within a large temperature variation range (-40-95 ℃) without generating obvious back focal drift; the lens adopts a 6-lens structure, so that the cost is low; the application of the cemented lens simplifies the assembly process; in the application of the projection lens, a telecentric optical path design is adopted at the reduction end (object side) of the lens, so that the lens has larger assembly tolerance and better general adaptability.

The optical lens according to the present application has wide applications, and is useful, for example, as an in-vehicle lens, a projection lens, and the like. It is to be understood that when used as an onboard lens, the optical lens according to the present application has a light ray direction from the front end to the rear end, i.e., the light ray passes from the first lens to the sixth lens and then to the imaging surface. It should be understood that when used as a projection lens, the optical lens according to the present application has a light direction from the rear end to the front end, i.e., the light is transmitted from the sixth lens to the first lens and then projected on the projection object.

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 six lenses are exemplified in the embodiment, the optical lens is not limited to including six 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.

Example 1

An optical lens according to embodiment 1 of the present application is described below with reference to fig. 1. Fig. 1 shows a schematic structural diagram of an optical lens according to embodiment 1 of the present application.

As shown in fig. 1, the optical lens includes, in order from the front end to the rear end side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6.

The first lens L1 is a meniscus lens with positive power, with the front facet S1 being convex and the back facet S2 being concave.

The second lens L2 is a meniscus lens with negative power, and its front side S3 is convex and its back side S4 is concave.

The third lens L3 is a biconcave lens with negative optical power, and its front side S6 is concave and its back side S7 is concave. The fourth lens L4 is a biconvex lens with positive optical power, and has a convex front surface S7 and a convex rear surface S8. The third lens L3 and the fourth lens L4 are cemented together to form a cemented lens.

The fifth lens L5 is a meniscus lens with positive power, and its front side S9 is concave and its back side S10 is convex.

The sixth lens L6 is a biconvex lens with positive refractive power, and has a convex front surface S11 and a convex rear surface S12.

The first lens element L1 to the sixth lens element L6 are all spherical lenses.

Alternatively, in the case where the optical lens is used as an in-vehicle lens, a filter and/or a protective lens may be provided after the sixth lens L6 of the optical lens. The optical filter can be used for correcting color deviation, and the protective lens can be used for protecting an image sensing chip positioned on the imaging plane IMA. The light from the object sequentially passes through the respective surfaces S1 to S12 and is finally imaged on the imaging surface S13.

Alternatively, in the case where the optical lens is used as a projection lens, another prism/field lens may be provided after the sixth lens L6, and since the prism/field lens has a large thickness, it is necessary to make the back focus of the lens long and to make the telecentricity good. The prism is used for transiting the illumination end and the imaging end of the projection lens; the field lens can correct aberration and improve the capability of marginal beam incidence. In the case where the optical lens is used as a projection lens, the light direction of the projection lens is from the rear end to the front end (reduction end to enlargement end), that is, the light from the light emission source surface S13 passes through the respective surfaces S12 to S1 in order and is finally projected on the projection object.

In the present embodiment, a stop disposed between the second lens L2 and the third lens L3 may be further included in the optical lens to improve the imaging quality.

Table 1 shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 1, where the radius of curvature R and the thickness T are both in units of millimeters (mm).

TABLE 1

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	19.8545	5.0058	1.81	44.00
2	80.6576	1.9329
					3	11.5571	5.0225	1.60	36.20
4	4.2779	3.7274
					STO	All-round	2.4195
6	-14.0547	4.0011	1.85	46.80
					7	53.9618	3.8396	1.50	64.60
8	-8.0174	0.1093
					9	-83.5844	2.5978	1.77	39.60
10	-27.1230	1.0133
					11	33.4470	3.2022	1.76	49.60
12	-31.2010	15.3176
					IMA	All-round

The present embodiment adopts six lenses as an example, and by reasonably distributing the focal power and the surface type of each lens, the center thickness of each lens and the air space between each lens, the lens can have at least one of the advantages of miniaturization, back focal length, high resolution, good thermal stability, low cost, high projection quality and the like.

Table 2 below gives the total optical length TTL of the optical lens of embodiment 1 (for example, TTL is an on-axis distance from the center of the front side surface S1 of the first lens L1 to the imaging surface S13 in an in-vehicle lens; for example, TTL is an on-axis distance from the center of the front side surface S1 of the first lens L1 to the light-emitting source surface S13 in a projection lens), the entire group focal length value F of the optical lens, the optical back focal length BFL of the optical lens (for example, BFL is an on-axis distance from the center of the back side surface S12 of the sixth lens L6 to the imaging surface S13 in an in-vehicle lens), the radius of curvature R3 of the front side surface S3 of the second lens L2, the radius of curvature R6862 of the back side surface S4 of the second lens L2, the value R69556 of the first lens L6356, the value F of the second lens L8653, the focal length value R3 of the combined focal length F of the third lens L8672 and the fourth focal length F of the second lens L8672, 36867, the third lens L8672F, the third lens L8672 and the fourth lens L867 in the projection lens L6, A combined focal length value F56 of the fifth lens L5 and the sixth lens L6, a radius of curvature R11 of a front side surface S11 of the sixth lens L6, a radius of curvature R12 of a rear side surface S12 of the sixth lens L6, and a thickness d3 of the second lens L2.

TABLE 2

TTL(mm)	48.189	R3(mm)	11.557
				F(mm)	16.963	R4(mm)	4.278
BFL(mm)	15.318	d3(mm)	5.022
				F1(mm)	31.360	R11(mm)	33.447
F2(mm)	-15.291	R12(mm)	-31.201
				F34(mm)	75.431
F56(mm)	15.390

In the present embodiment, TTL/F is 2.84 between the total optical length TTL of the optical lens and the entire focal length F of the optical lens; the optical back focal length BFL of the optical lens and the whole group focal length value F of the optical lens meet the condition that BFL/F is 0.90; the radius of curvature R3 of the front side surface of the second lens, the radius of curvature R4 of the rear side surface of the second lens and the thickness d3 of the second lens meet the condition that R3/(R4+ d3) is 1.24; F1/F2 is-2.05 between the focal length value F1 of the first lens and the focal length value F2 of the second lens; F34/F is 4.45 between the combined focal length value F34 of the third lens and the fourth lens and the whole focal length value F of the optical lens; F56/F is equal to 0.91 between the combined focal length value F56 of the fifth lens and the sixth lens and the whole focal length value F of the optical lens; and the radius of curvature R11 of the sixth lens front side surface and the radius of curvature R12 of the sixth lens rear side surface satisfy-1.07 for R11/R12.

Example 2

An optical lens according to embodiment 2 of the present application is described below with reference to fig. 2. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 2 shows a schematic structural diagram of an optical lens according to embodiment 2 of the present application.

As shown in FIG. 2, the optical lens includes, in order from the front end to the rear end

A first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6.

The fifth lens L5 is a plano-convex lens with positive optical power, and its front side S9 is a plane and its rear side S10 is a convex surface.

Alternatively, in the case where the optical lens is used as a projection lens, another prism/field lens may be provided after the sixth lens L6, and the prism/field lens has a large thickness, so that a long back focus and good telecentricity are required. The prism is used for transiting the illumination end and the imaging end of the projection lens; the field lens can correct aberration and improve the capability of marginal beam incidence. In the case where the optical lens is used as a projection lens, the light direction of the projection lens is from the rear end to the front end (reduction end to enlargement end), that is, the light from the light emission source surface S13 passes through the respective surfaces S12 to S1 in order and is finally projected on the projection object.

Table 3 below shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 2, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 4 below gives the results of example 2

An optical total length TTL of the optical lens, a full group focal length value F of the optical lens, an optical back focal length BFL of the optical lens, a radius of curvature R3 of a front side S3 of the second lens L2, a radius of curvature R4 of a back side S4 of the second lens L2, a focal length value F1 of the first lens L1, a focal length value F2 of the second lens L2, a combined focal length value F34 of the third lens L3 and the fourth lens L4, a combined focal length value F56 of the fifth lens L5 and the sixth lens L6, a radius of curvature R11 of a front side S11 of the sixth lens L6, a radius of curvature R12 of a back side S12 of the sixth lens L6, and a thickness d3 of the second lens L2.

TABLE 3

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe of AbbeNumber Vd
					1	20.1288	5.0033	1.81	44.00
2	83.8126	1.9022
					3	11.8718	5.0176	1.60	36.20
4	4.4098	3.9039
					STO	All-round	2.7158
6	-12.9861	4.0027	1.85	46.80
					7	82.7830	3.5694	1.50	64.60
8	-8.1150	0.1081
					9	All-round	2.7421	1.77	39.60
10	-31.3729	1.0121
					11	35.9479	3.1154	1.76	49.60
12	-33.7019	15.2885
					IMA	All-round

TABLE 4

TTL(mm)	48.381	R3(mm)	11.872
				F(mm)	16.962	R4(mm)	4.410
BFL(mm)	15.288	d3(mm)	5.018
				F1(mm)	31.594	R11(mm)	35.948
F2(mm)	-15.656	R12(mm)	-33.702
				F34(mm)	99.009
F56(mm)	15.213

In the present embodiment, TTL/F is 2.85, which is satisfied between the total optical length TTL of the optical lens and the entire focal length F of the optical lens; the optical back focal length BFL of the optical lens and the whole group focal length value F of the optical lens meet the condition that BFL/F is 0.90; the radius of curvature R3 of the front side surface of the second lens, the radius of curvature R4 of the rear side surface of the second lens and the thickness d3 of the second lens meet the condition that R3/(R4+ d3) is 1.26; F1/F2 is-2.02 between the focal length value F1 of the first lens and the focal length value F2 of the second lens; F34/F is 5.84 between the combined focal length value F34 of the third lens and the fourth lens and the whole focal length value F of the optical lens; F56/F is equal to 0.90 between the combined focal length value F56 of the fifth lens and the sixth lens and the whole focal length value F of the optical lens; and the radius of curvature R11 of the sixth lens front side surface and the radius of curvature R12 of the sixth lens rear side surface satisfy-1.07 for R11/R12.

Example 3

An optical lens according to embodiment 3 of the present application is described below with reference to fig. 3. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 3 shows a schematic structural diagram of an optical lens according to embodiment 3 of the present application.

As shown in FIG. 3, the optical lens includes, in order from the front end to the rear end

The fifth lens L5 is a biconvex lens with positive optical power, and has a convex front surface S9 and a convex rear surface S10.

Table 5 below shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 3, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 6 below gives the total optical length TTL of the optical lens, the entire group focal length value F of the optical lens, the optical back focal length BFL of the optical lens, the radius of curvature R3 of the front side S3 of the second lens L2, the radius of curvature R4 of the back side S4 of the second lens L2, the focal length value F1 of the first lens L1, the focal length value F2 of the second lens L2, the combined focal length value F34 of the third lens L3 and the fourth lens L4, the combined focal length value F56 of the fifth lens L5 and the sixth lens L6, the radius of curvature R11 of the front side S11 of the sixth lens L6, the radius of curvature R12 of the back side S12 of the sixth lens L6, and the thickness d3 of the second lens L2 of example 3.

TABLE 5

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	21.4547	5.0011	1.81	44.00
2	100.0002	2.0000
					3	11.3007	5.0069	1.60	36.20
4	4.5105	4.0017
					STO	All-round	2.2870
6	-13.4231	4.0011	1.85	46.80
					7	57.5669	5.0002	1.50	64.60
8	-8.5159	0.1094
					9	52.0975	2.8566	1.77	39.60
10	-46.0975	0.4998
					11	48.0975	2.8566	1.76	49.60
12	-44.0975	15.4044
					IMA	All-round

TABLE 6

TTL(mm)	49.025	R4(mm)	4.510
				F(mm)	17.323	d3(mm)	5.007
BFL(mm)	15.404	R11(mm)	48.097
				F1(mm)	33.049	R12(mm)	-44.097
F2(mm)	-17.439	R9(mm)	52.097
				F34(mm)	100.006	R10(mm)	-46.097
F56(mm)	16.249
				R3(mm)	11.301

In the present embodiment, TTL/F is 2.84 between the total optical length TTL of the optical lens and the entire focal length F of the optical lens; the optical back focal length BFL of the optical lens and the whole group focal length value F of the optical lens meet the condition that BFL/F is 0.89; the radius of curvature R3 of the front side surface of the second lens, the radius of curvature R4 of the rear side surface of the second lens and the thickness d3 of the second lens meet the condition that R3/(R4+ d3) is 1.19; F1/F2 is-1.90 between the focal length value F1 of the first lens and the focal length value F2 of the second lens; F34/F is 5.80 between the combined focal length value F34 of the third lens and the fourth lens and the whole focal length value F of the optical lens; F56/F is equal to 0.94 between the combined focal length value F56 of the fifth lens and the sixth lens and the whole group focal length value F of the optical lens; the radius of curvature R11 of the front side surface of the sixth lens and the radius of curvature R12 of the rear side surface of the sixth lens meet the condition that R11/R12 is-1.09; and the radius of curvature R9 of the front side surface of the fifth lens and the radius of curvature R10 of the rear side surface of the fifth lens satisfy R9/R10-1.13.

In summary, examples 1 to 3 each satisfy the relationship shown in table 7 below.

TABLE 7

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. The optical lens sequentially comprises from the front end to the rear end: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens,

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

the first lens has positive focal power, the front side surface of the first lens is a convex surface, and the back side surface of the first lens is a concave surface;

the second lens has negative focal power, the front side surface of the second lens is a convex surface, and the back side surface of the second lens is a concave surface;

the third lens has negative focal power, and both the front side surface and the back side surface of the third lens are concave surfaces;

the fourth lens has positive focal power, and the front side surface and the back side surface of the fourth lens are convex surfaces;

the fifth lens has positive focal power, and the back side surface of the fifth lens is a convex surface;

the sixth lens has positive focal power, and the front side surface and the back side surface of the sixth lens are convex surfaces; and

the third lens is cemented with the fourth lens.

2. An optical lens barrel according to claim 1, wherein the front side of the fifth lens is concave.

3. An optical lens barrel according to claim 1, wherein the front side of the fifth lens is planar.

4. An optical lens barrel according to claim 1, wherein the front side of the fifth lens element is convex.

5. An optical lens as claimed in claim 4, characterized in that the radius of curvature R9 of the front side of the fifth lens and the radius of curvature R10 of the rear side of the fifth lens satisfy: R9/R10 is not less than-1.6 and not more than-0.5.

6. An optical lens according to any one of claims 1 to 5, wherein the total optical length TTL of the optical lens and the entire set of focal length values F of the optical lens satisfy: TTL/F is less than or equal to 4.

7. An optical lens according to any of claims 1-5, characterized in that between the optical back focal length BFL of the optical lens and the entire set of focal length values F of the optical lens there is satisfied: BFL/F is more than or equal to 0.6.

8. An optical lens according to any one of claims 1 to 5, characterized in that the radius of curvature R3 of the front side of the second lens, the radius of curvature R4 of the rear side of the second lens and the thickness d3 of the second lens are such that: R3/(R4+ d3) is more than or equal to 0.6 and less than or equal to 1.5.

9. An optical lens according to any one of claims 1 to 5, characterized in that between the focal length value F1 of the first lens and the focal length value F2 of the second lens, it is satisfied that: f1 of-3 is less than or equal to that of F2 is less than or equal to-0.4.

10. An optical lens according to any one of claims 1 to 5, characterized in that a combined focal length value F34 of the third lens and the fourth lens and a full set of focal length values F of the optical lens satisfy: F34/F is more than or equal to 2 and less than or equal to 8.

11. An optical lens according to any one of claims 1 to 5, characterized in that a combined focal length value F56 of the fifth lens and the sixth lens and a full set of focal length values F of the optical lens satisfy: F56/F is more than or equal to 0.5 and less than or equal to 1.3.

12. An optical lens barrel according to any one of claims 1 to 5, wherein a radius of curvature R11 of the front side surface of the sixth lens and a radius of curvature R12 of the rear side surface of the sixth lens satisfy: R11/R12 is not less than-1.4 and not more than-0.6.

13. The optical lens sequentially comprises from the front end to the rear end: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens,

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

the first lens, the fourth lens, the fifth lens, and the sixth lens have positive optical power;

the second lens and the third lens have negative optical power;

the front side surfaces of the first lens and the second lens are convex surfaces, and the back side surfaces of the first lens and the second lens are concave surfaces;

the front side and the back side of the fourth lens and the sixth lens are convex surfaces; and

the total optical length TTL of the optical lens and the whole group of focal length values F of the optical lens meet the following conditions: TTL/F is less than or equal to 4.

14. An optical lens barrel according to claim 13, wherein the front side surface of the fifth lens element is concave and the rear side surface is convex.

15. An optical lens barrel according to claim 13, wherein the front side of the fifth lens element is flat and the rear side is convex.

16. An optical lens barrel according to claim 13, wherein the front side and the rear side of the fifth lens are convex.

17. An optical lens as claimed in claim 16, characterized in that the radius of curvature R9 of the front side of the fifth lens and the radius of curvature R10 of the rear side of the fifth lens satisfy: R9/R10 is not less than-1.6 and not more than-0.5.

18. An optical lens according to any of claims 13-17, characterized in that between the optical back focal length BFL of the optical lens and the entire set of focal length values F of the optical lens is satisfied: BFL/F is more than or equal to 0.6.

19. An optical lens according to any of claims 13-17, characterized in that the radius of curvature R3 of the front side of the second lens, the radius of curvature R4 of the rear side of the second lens and the thickness d3 of the second lens are such that: R3/(R4+ d3) is more than or equal to 0.6 and less than or equal to 1.5.

20. An optical lens element according to any of claims 13-17, characterized in that between the focal value F1 of the first lens and the focal value F2 of the second lens, it is satisfied that: f1 of-3 is less than or equal to that of F2 is less than or equal to-0.4.

21. An optical lens according to any one of claims 13 to 17, characterized in that a combined focal length value F34 of the third lens and the fourth lens and a full set of focal length values F of the optical lens satisfy: F34/F is more than or equal to 2 and less than or equal to 8.

22. An optical lens according to any one of claims 13 to 17, characterized in that a combined focal length value F56 of the fifth lens and the sixth lens and a full set of focal length values F of the optical lens satisfy: F56/F is more than or equal to 0.5 and less than or equal to 1.3.

23. An optical lens element according to any one of claims 13 to 17, characterized in that the radius of curvature R11 of the front side of the sixth lens element and the radius of curvature R12 of the rear side of the sixth lens element satisfy: R11/R12 is not less than-1.4 and not more than-0.6.

24. An optical lens barrel according to claim 13, wherein the front side and the rear side of the third lens are both concave.

25. An optical lens according to claim 13, characterized in that the third lens is cemented with the fourth lens.