CN113296217A

CN113296217A - Imaging lens

Info

Publication number: CN113296217A
Application number: CN202110614297.0A
Authority: CN
Inventors: 常斌全; 毛鑫伟; 赵烈烽; 戴付建
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2021-06-02
Filing date: 2021-06-02
Publication date: 2021-08-24

Abstract

The invention relates to an imaging lens, which comprises a lens barrel (1) and a lens group (2) arranged in the lens barrel (1), wherein the lens group (2) comprises a first lens (21) and a second lens (22) which are sequentially arranged from an object side to an image side along an optical axis, the first lens (21) and the second lens (22) are respectively provided with an optical effective part and a non-optical effective part, an annular bulge (21a) is arranged on the image side of the non-optical effective part of the first lens (21), an annular groove (22a) is arranged on the object side of the non-optical effective part of the second lens (22), and in the mounting state, the annular bulge (21a) is positioned in the annular groove (22a) and forms interference fit. The invention can realize good stability of lens assembly by embedding the front two lenses of the lens set.

Description

Imaging lens

Technical Field

The invention relates to the technical field of optical elements, in particular to an imaging lens.

Background

Along with the development of imaging products towards the direction of integration and convenience, the imaging quality is guaranteed by the imaging lens matched with the imaging lens, and the volume of the imaging lens is required to be reduced as much as possible so as to reduce the space ratio of the whole imaging module. Meanwhile, for digital products such as mobile phones carrying front cameras, a comprehensive screen technology or a screen display technology as large as possible also becomes a core competition point. The development of the comprehensive screen technology forms a process of gradually approaching the ultimate full-face screen through a Liuhai screen with a larger non-effective display area and a shape similar to that of Liuhai, a water drop screen with a shape similar to that of a water drop at the edge of the screen, a hole digging screen similar to a round small black dot arranged at the corner of the screen and an extreme point screen with a smaller light-transmitting screen hole. In the prior art, the mounting space on the object side of the lens is compressed to realize a full-face screen, and therefore, it is important to reduce the size of the imaging lens.

Disclosure of Invention

The present invention is directed to solving the above problems and to providing an imaging lens.

In order to achieve the above object, the present invention provides an imaging lens, including a lens barrel and a lens group disposed in the lens barrel, where the lens group includes a first lens and a second lens sequentially arranged from an object side to an image side along an optical axis, the first lens and the second lens each have an optical effective portion and a non-optical effective portion, an annular protrusion is disposed on the image side of the non-optical effective portion of the first lens, an annular groove is disposed on the object side of the non-optical effective portion of the second lens, and in an installation state, the annular protrusion is located in the annular groove and forms an interference fit.

According to one aspect of the present invention, the outer annular surface of the annular protrusion and the outer groove wall of the annular groove are both cylindrical surfaces or conical surfaces, and the inner annular surface of the annular protrusion and the inner groove wall of the annular groove are both conical surfaces or cylindrical surfaces.

According to an aspect of the present invention, a width e of the non-optically effective portion of the first lens in the radial direction of the first lens and a half aperture R of the first lens satisfy the following relationship: 0.01< e/R < 0.3.

According to an aspect of the present invention, an optical power of the optically effective portion of the first lens near the object side surface is positive;

the passing rates T of the first lens and the second lens in the wave band of 420nm-750nm are both more than 85%.

According to an aspect of the present invention, the thickness a of the first lens, the thickness b of the edge, and the thickness c of the thinnest portion satisfy the following relationships, respectively: a is more than or equal to 0.8mm, b/a is more than or equal to 0.1 and less than or equal to 0.5, and c/a is more than or equal to 0.08 and less than 0.3.

According to an aspect of the present invention, the height h and the top width d of the annular protrusion satisfy the following conditions, respectively: h is more than or equal to 0.08mm and less than or equal to 0.2mm, and d is more than or equal to 0.08 mm.

According to one aspect of the invention, the depth k and the groove bottom width g of the annular groove and the height h and the top width d of the annular protrusion respectively satisfy the following relations: k is more than or equal to h, g is more than d.

According to one aspect of the invention, the semi-aperture R of the second lens is larger than the semi-aperture R of the first lens, and the semi-apertures of the two satisfy the following relation: R-R is more than or equal to 0.08 mm.

According to one aspect of the present invention, the front end of the lens barrel has a section of barrel wall perpendicular to the optical axis, and the object side surface of the non-optical effective part of the second lens bears against the barrel wall;

the wall thickness w meets the following conditions: w is more than or equal to 0.25mm, and the flatness of the image side surface of the cylinder wall and the object side surface of the non-optical effective part of the second lens is within 0.0015 mm.

According to one aspect of the invention, an outer side surface of the second lens forms an interference fit with an inner wall of the lens barrel.

According to one aspect of the invention, at least three lenses are included in the lens group.

According to an aspect of the present invention, the lens barrel front end outer diameter Φ satisfies the following condition: phi is less than or equal to 2 mm;

the depth L of the front end of the lens cone meets the following conditions: l is more than 0.5 mm.

According to one aspect of the invention, the first lens and the second lens are fixed by dispensing, and the non-optical effective part of the first lens is processed by laser atomization.

According to the concept of the present invention, an annular protrusion and an annular groove are provided in the non-optically effective portions of the two lenses of the lens group closest to the object side, respectively. Therefore, the annular bulge and the annular groove can be embedded, so that the two lenses are assembled into a whole, and the assembling stability of the lens can be improved. In addition, the first lens and the second lens can be assembled into a whole, so that the lens barrel only needs to be designed to be capable of axially and radially positioning the second lens, namely the front end of the lens barrel does not need to bear the abutting of the first lens, and the barrel wall of the position can be thinned, so that the size of the head of the lens is further reduced.

According to an aspect of the present invention, the first lens and the second lens have a high throughput in a specific wavelength band, so that MTF performance of the lens can be ensured.

According to one scheme of the invention, good embedding effect can be ensured by reasonably setting the height of the annular bulge and the width of the top ring.

According to one scheme of the invention, the relationship between the depth and the width of the annular groove and the height and the top annular width of the annular bulge is reasonably set, so that a good pre-tightening effect can be ensured when the two lenses are matched.

According to one scheme of the invention, the first lens is small and thick by reasonably setting the semi-caliber relation between the first lens and the second lens, so that the head size of the lens is further ensured to be small.

Drawings

Fig. 1 schematically shows a configuration diagram of an imaging lens of an embodiment of the present invention;

fig. 2 is a schematic diagram showing the fitting of first and second lenses in an imaging lens according to an embodiment of the present invention;

fig. 3 is a schematic view showing the head size of an imaging lens according to an embodiment of the present invention;

FIG. 4 is a schematic diagram showing the radial dimensions (left: object side; right: image side) of portions of a first lens in an imaging lens according to an embodiment of the invention;

fig. 5 is a schematic view showing axial dimensions of portions of a first lens in an imaging lens according to an embodiment of the present invention;

fig. 6 is a schematic diagram showing the dimensions of an annular projection of a first lens in an imaging lens according to an embodiment of the present invention;

fig. 7 is a schematic diagram showing the sizes of portions of a second lens in an imaging lens according to an embodiment of the present invention;

fig. 8 is a schematic diagram showing the dimensions of the front end of the lens barrel in the imaging lens according to the embodiment of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship that is based on the orientation or positional relationship shown in the associated drawings, which is for convenience and simplicity of description only, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above-described terms should not be construed as limiting the present invention.

The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are not limited to the following embodiments.

Referring to fig. 1, the imaging lens of the present invention includes a lens barrel 1 and a lens group 2 disposed in the lens barrel 1, and lenses in the lens group 2 are disposed coaxially with the lens barrel 1. The lens group 2 includes a first lens 21 and a second lens 22 arranged in order from the object side to the image side along the optical axis. The first lens 21 and the second lens 22 each have an optically effective portion and a non-optically effective portion. Generally, the central portion of the lens is the optically effective portion, while the outer edge of the lens, which merely serves as a bearing, is the non-optically effective portion.

Referring to fig. 2, the first lens element 21 has an annular protrusion 21a on the image side of the non-optically effective portion, and the second lens element 22 has an annular groove 22a on the object side of the non-optically effective portion. According to the concept of the present invention, in the mounted state, the annular projection 21a is located in the annular groove 22a, so that the first lens 21 and the second lens 22 form a fitting fit. And, the inner and outer ring surfaces of the annular protrusion 21a are closely attached to the inner and outer groove walls of the annular groove 22a, respectively. Thus, the annular protrusion 21a and the annular groove 22a form an interference fit, so that the first lens 21 and the second lens 22 are not loosened, and the assembly stability of the lens is improved.

When assembling the lens barrel, the first lens 21 is first mounted on the second lens 22, then the two lenses are mounted in the lens barrel 1 as a whole, so that the object-side ring plane of the non-optical effective part of the second lens 22 abuts against the barrel wall of the lens barrel 1, and the rest lenses, the shading element and the like are sequentially mounted. Therefore, the first lens 21 and the second lens 22 are assembled as a whole, that is, only the second lens 22 needs to be axially and radially positioned during installation, and the first lens 21 does not need to be supported on the cylinder wall of the lens barrel 1, so that the front end of the lens barrel 1 does not need to have high strength, and the cylinder wall at the position can be thinned, thereby further reducing the size of the head of the lens.

Referring to fig. 2, in the present embodiment, the outer annular surface of the annular projection 21a is a cylindrical surface, and is substantially flush with the outer annular surface of the first lens 21. However, the position of the annular projection 21a is as far as possible not to exceed the outer annular surface of the first lens 21, i.e., outside the optically effective portion of the first lens 21 but inside the outer diameter edge of the first lens 21. The inner annular surface of the annular protrusion 21a is a conical surface with the vertex facing the object side. The outer groove wall of the annular groove 22a is cylindrical so as to be fitted with the outer cylindrical surface of the annular projection 21 a. The inner wall of the annular groove 22a is a conical surface with its vertex facing the object side, so as to be able to cooperate with the inner conical surface of the annular protrusion 21 a. Thus, the annular protrusion 21a and the annular groove 22a have a good fitting effect, so that the two lenses are more firmly embedded and connected, and the stability of lens assembly is further improved. Of course, in other embodiments, the toroidal shapes of the annular protrusion 21a and the annular groove 22a may be reversed, as long as they can be engaged with each other.

As shown in fig. 3, the characteristics of the small head of the lens are realized according to the above arrangement, that is, the outer diameter Φ of the front end of the lens barrel 1 satisfies the following conditions: phi is less than or equal to 2 mm; the depth L of the front end of the lens cone meets the following conditions: l is more than 0.5 mm. Of course, the number n of lenses included in the lens group 2 is preferably at least three (i.e., n ≧ 3), and a plurality of light-shielding elements may be provided between the lenses, but the first and second two lenses arranged at the front ends need to be fitted as described above. In addition, the focal power of the optical effective part of the first lens 21 close to the object side surface is positive, and the passing rate T of the first lens 21 and the second lens 22 in the wave band of 420nm-750nm satisfies T ≥ 85%. Therefore, the first lens and the second lens have high transmittance, and the MTF performance of the lens is ensured.

Referring to fig. 4, the width e of the non-optically effective portion of the first lens 21 in the radial direction of the first lens 21 and the half-aperture R of the first lens 21 satisfy the following relationship: 0.01< e/R < 0.3. Of course, as can be seen from fig. 4, due to the special structure of the first lens 21, the optically effective portion and the non-optically effective portion divided into the object side (left) and the image side (right) are different, but both f and e denote the optically effective portion and the non-optically effective portion, i.e., R ═ e + f. Therefore, the entire size of the first lens 21 satisfies the above relational expression. As can also be seen from the above, the non-optically effective portion of the first lens 21 of the present invention is also small relative to conventional optics.

Referring to fig. 5, the thickness a of the middle, the thickness b of the edge, and the thickness c of the thinnest portion of the first lens 21 satisfy the following relationship: a is more than or equal to 0.8mm, b/a is more than or equal to 0.1 and less than or equal to 0.5, and c/a is more than or equal to 0.08 and less than 0.3. The thickness a can be understood as the axial dimension of the center of the lens, i.e. the center of the optically effective portion. The edge thickness b is the axial dimension of the outermost edge of the lens, i.e. the outermost edge of the non-optically active portion, and for the present invention, the edge thickness b is the height of the original lens edge thickness plus the annular protrusion 21a due to the provision of the annular protrusion 21 a. The thinnest thickness c indicates the location substantially between the optically effective portion and the annular protrusion 21 a.

As can be seen from fig. 6 and 7, in the present invention, the height h and the top width d (ring width) of the annular projection 21a satisfy the following conditions, respectively: h is more than or equal to 0.08mm and less than or equal to 0.2mm, and d is more than or equal to 0.08 mm. Satisfying the above-mentioned size setting can guarantee good gomphosis effect. The depth k and the groove bottom width g (ring width) of the annular groove 22a and the height h and the top width d of the annular protrusion 21a satisfy the following relationships, respectively: k is more than or equal to h, g is more than d. Satisfying the above dimensions, the annular boss 21a and the annular groove 22a can form a good embedding relationship, and the two lenses can also form a pre-tightening effect, thereby further ensuring the assembly stability of the lens.

As can be seen from fig. 4 and 7, in the present invention, the half-aperture R of the second lens 22 is larger than the half-aperture R of the first lens 21, and the half-apertures of the first and

second lenses

21 and 22 further satisfy the following relationship: R-R is more than or equal to 0.08 mm. Thus, after the second lens 22 forms an interference fit with the lens barrel 1, the first lens 21 does not contact the lens barrel 1, so that the front end barrel wall of the lens barrel 1 can be thinned. Also, this size setting makes the first lens 21 small and thick, thereby further ensuring that the lens head is small.

Referring to fig. 8, the front end of the lens barrel 1 has a section of barrel wall perpendicular to the axial direction (i.e. optical axis) of the lens barrel 1, so that it can be used to bear against the object side surface of the non-optical effective part of the second lens 22 to axially position the second lens 22. In the invention, the wall thickness w (or called axial thickness) meets the following condition: w is more than or equal to 0.25mm, so that enough bearing strength can be ensured. In addition, the flatness of the object-side surface of the non-optical effective part of the second lens 22 and the image-side surface (i.e. the bearing surface) of the section of the cylinder wall is controlled within 0.0015mm, so that the assembling precision of the lens can be ensured to realize better assembling effect. The outer side surface of the second lens 22 forms an interference fit with the inner wall of the lens barrel 1 (i.e. the inner ring surface of the lens barrel 1 indicated by the radius s), i.e. r > s, so as to position the second lens 22 in the radial direction. In addition, in the present invention, after the first lens 21 and the second lens 22 are embedded, the embedded position can be fixed by dispensing, so as to further improve the assembly stability. The non-optically effective portion of the first lens 21 may be further subjected to laser atomization to form a rough surface.

In conclusion, the imaging lens of the invention has smaller head size and can meet the development requirement of small head lenses. Moreover, the mode of embedding and connecting two lenses closest to the object side in the lens group can obviously improve the assembly stability of the lens, and can greatly reduce the required thickness of the cylinder wall of the front end of the lens barrel, thereby further reducing the size of the front end of the lens.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An imaging lens comprising a lens barrel (1) and a lens group (2) disposed in the lens barrel (1), the lens group (2) comprising a first lens (21) and a second lens (22) arranged in order from an object side to an image side along an optical axis, the first lens (21) and the second lens (22) each having an optically effective portion and a non-optically effective portion, an annular protrusion (21a) being disposed on an image side of the non-optically effective portion of the first lens (21), and an annular groove (22a) being disposed on an object side of the non-optically effective portion of the second lens (22), characterized in that, in a mounted state, the annular protrusion (21a) is located in the annular groove (22a) and forms an interference fit.

2. The imaging lens according to claim 1, characterized in that the outer annular surface of the annular projection (21a) and the outer groove wall of the annular groove (22a) are both cylindrical surfaces or conical surfaces, and the inner annular surface of the annular projection (21a) and the inner groove wall of the annular groove (22a) are both conical surfaces or cylindrical surfaces.

3. An imaging lens according to claim 1, characterized in that a width e of the non-optically effective portion of the first lens (21) in a radial direction of the first lens (21) and a half aperture R of the first lens (21) satisfy the following relationship: 0.01< e/R < 0.3.

4. Imaging lens according to claim 1, characterized in that the optical power of the optically effective part of the first lens (21) close to the object side is positive;

the first lens (21) and the second lens (22) have a transmittance T of 85% or more in a wavelength range of 420nm to 750 nm.

5. The imaging lens according to claim 1, wherein the thickness a of the middle thickness, the thickness b of the side, and the thickness c of the thinnest portion of the first lens (21) satisfy the following relationships, respectively: a is more than or equal to 0.8mm, b/a is more than or equal to 0.1 and less than or equal to 0.5, and c/a is more than or equal to 0.08 and less than 0.3.

6. An imaging lens according to claim 1, characterized in that the height h and the top width d of the annular protrusion (21a) satisfy the following conditions, respectively: h is more than or equal to 0.08mm and less than or equal to 0.2mm, and d is more than or equal to 0.08 mm.

7. The imaging lens according to claim 1, characterized in that the depth k, the groove bottom width g of the annular groove (22a) and the height h, the top width d of the annular protrusion (21a) satisfy the following relationships, respectively: k is more than or equal to h, g is more than d.

8. Imaging lens according to claim 1, characterized in that the semi-aperture R of the second lens (22) is greater than the semi-aperture R of the first lens (21) and the semi-apertures of the two satisfy the following relationship: R-R is more than or equal to 0.08 mm.

9. Imaging lens according to claim 1, characterized in that the front end of the barrel (1) has a section of a cylinder wall perpendicular to the optical axis against which the object-side face of the non-optically active part of the second lens (22) bears;

the wall thickness w meets the following conditions: w is more than or equal to 0.25mm, and the flatness of the image side surface of the cylinder wall and the object side surface of the non-optical effective part of the second lens (22) is within 0.0015 mm.

10. Imaging lens according to claim 1, characterized in that the outer side of the second lens (22) forms an interference fit with the inner wall of the barrel (1).

11. An imaging lens according to claim 1, characterized in that the lens group (2) comprises at least three lenses.

12. The imaging lens according to claim 1, characterized in that the lens barrel (1) has a front end outer diameter Φ that satisfies the following condition: phi is less than or equal to 2 mm;

the depth L of the front end of the lens barrel (1) meets the following conditions: l is more than 0.5 mm.

13. Imaging lens according to claim 1, characterized in that the first lens (21) and the second lens (22) are fixed by dispensing, and the non-optically effective portion of the first lens (21) is processed by laser atomization.