CN114397749A

CN114397749A - Glass-plastic mixed wide-angle lens

Info

Publication number: CN114397749A
Application number: CN202210049458.0A
Authority: CN
Inventors: 田强军; 刘绪明; 刘鹏
Original assignee: Dongguan Rongguang Optical Co ltd
Current assignee: Dongguan Rongguang Optical Co ltd
Priority date: 2022-01-17
Filing date: 2022-01-17
Publication date: 2022-04-26

Abstract

A glass-plastic mixed wide-angle lens comprises a first lens group, a diaphragm and a second lens group in sequence from an object side to an image side, wherein the first lens group comprises a first lens with negative focal power, a convex surface facing to the object side and a concave surface facing to the diaphragm, a second lens with negative focal power, a convex surface facing to the object side and a concave surface facing to the diaphragm, and a third lens with positive focal power and convex surfaces on two sides; the second lens group includes, from the diaphragm to the image side, a fourth lens having positive power and a convex surface facing the image side, a fifth lens having negative power, a sixth lens having power and a convex surface facing the object side, and a seventh lens having negative power; the surface of the seventh lens facing the image side is concave at the center and convex at the edge; the sixth lens and the seventh lens are aspheric plastic lenses. Low cost, short total system length and coke running amount less than 5 microns in the temperature range of-30 deg.c to 85 deg.c.

Description

Glass-plastic mixed wide-angle lens

Technical Field

The invention relates to the technical field of cameras, in particular to a glass-plastic mixed wide-angle lens.

Background

Along with the continuous development of science and technology, the field of making a video recording is constantly widened, and people are more and more popular when outdoor exercises, if ride, drive, tourism etc. note own nice time through the photography, share simultaneously on the social media.

At present, camera equipment for photographic recording work, life and the like in the market is more and more diversified, the requirements of consumers on the camera equipment are more and more rigorous, and the pixels are expected to be higher while the size is small. There are two common choices for improving the pixel, one is to select and use a chip with a smaller pixel size under the condition of ensuring that the size of the camera equipment is not increased, but the obvious defect is that the response speed and the noise of the chip are both deteriorated; secondly, the chip with a larger target surface is selected under the condition that the size of the pixel point is not changed, but the chip with the larger target surface means that the total length of the lens is also lengthened, so that the size of the camera equipment is increased. The general total lens length matched with the current market using 1/3 inch image sensor chips is over 20mm, and if 1/2 inch or larger chips are used, the total lens length can reach 30mm or even longer. In the second option, the lens similar to the lens imaging system of the mobile phone is used in the industry to solve the problem of the total length of the lens. However, there are two obvious problems with this option: 1) considering the aesthetic appearance of the camera device, consumers often want to reduce the thickness of the device without reducing the clear aperture of the first lens, and the obvious characteristic of the mobile phone lens is that the clear aperture of the first lens is small; 2) the mobile phone lens module uses the automatic focusing function, so the problem of high and low temperature focusing is not needed to be considered. In view of the problems in the prior art, a technical solution for solving the above technical problems is needed.

Disclosure of Invention

Aiming at the problems, the invention provides the glass-plastic mixed wide-angle lens which is low in cost, can realize very short total system length, simultaneously realizes full-field high-definition imaging, realizes image quality above 4K, and can realize that the out-of-focus amount is less than 5 microns within the temperature range of-30 ℃ to 85 ℃.

In order to achieve the purpose, the invention is solved by the following technical scheme:

a glass-plastic mixed wide-angle lens comprises a first lens group, a diaphragm and a second lens group in sequence from an object side to an image side, wherein the first lens group comprises a first lens with negative focal power, a convex surface facing the object side and a concave surface facing the diaphragm, a second lens with negative focal power, a convex surface facing the object side and a concave surface facing the diaphragm, and a third lens with positive focal power and convex surfaces on two sides; the second lens group includes, from the diaphragm to the image side, a fourth lens having positive power and a convex surface facing the image side, a fifth lens having negative power, a sixth lens having power and a convex surface facing the object side, and a seventh lens having negative power; the surface of the seventh lens facing the image side is concave at the center and convex at the edge; the sixth lens and the seventh lens are aspheric plastic lenses.

Further, it satisfies the conditional expression: CA₁>0.9CA_i；

Wherein: CA₁Representing the effective clear aperture, CA, of the first lens near the object side_iRepresenting the effective imaging plane aperture.

Further, it satisfies the conditional expression: -0.15 < phi₃+Φ₅＜0.15；

Wherein: phi₃Denotes the power of the third lens, phi₅Represents the power of the fifth lens.

Further, it satisfies the conditional expression: -0.1 < phi₆+Φ₇＜0.1，

Wherein phi₆Denotes the power of the sixth lens, phi₇Represents the optical power of the seventh lens.

Further, it satisfies the conditional expression: i f₄/f₅Ι>1.0；

Wherein f is₄Denotes the fourth lens focal length, f₅Denotes a focal length of the fifth lens.

Further, the third lens is a spherical glass lens.

The invention has the beneficial effects that:

1. in the invention, by arranging the third lens with positive focal power and convex surfaces on two sides and the seventh lens with a concave edge convex surface taking the surface facing the image side as the center, the total lens length can be controlled to be below 15mm under the condition that the target surface chip is enlarged;

2. the invention satisfies CA₁>0.9CA_iThe conditional expression can realize that the clear aperture of the first lens is large enough when the camera device looks at the appearance, and the attractiveness of the device is ensured;

3. the invention meets the requirement that phi is more than-0.15₃+Φ₅< 0.15 and-0.1 < phi₆+Φ₇The conditional expression is less than 0.1, and the third lens is a spherical glass lens, even under the condition that more plastic lenses are used, the extremely small focus running amount of the lens head in the temperature range of-30 ℃ to 85 ℃ can be realized, and the embodiment is less than 5 micrometers;

4. the invention satisfies I f₄/f₅Ι>1.0 conditional expression, the on-axis resolution can be improved.

Drawings

Fig. 1 is a schematic cross-sectional structure view of a glass-plastic hybrid wide-angle lens according to a first embodiment of the present invention.

Fig. 2 is a graph showing an optical transfer function of a glass-plastic hybrid wide-angle lens according to a first embodiment of the present invention.

Fig. 3 is a dot-column diagram graph of the glass-plastic hybrid wide-angle lens in the first embodiment of the present invention.

FIG. 4 is a low-temperature on-axis defocus curve (-30 ℃ C.; thin line: 20 ℃ C., thick line: 30 ℃ C.) of the glass-plastic hybrid wide-angle lens in the first embodiment of the present invention.

FIG. 5 is an on-axis defocus graph (85 ℃ C.; thin line 20 ℃ C., thick line 85 ℃ C.) for the high temperature of the glass-plastic hybrid wide-angle lens in the first embodiment of the present invention.

Fig. 6 is a schematic cross-sectional structure view of a glass-plastic hybrid wide-angle lens according to a second embodiment of the present invention.

Fig. 7 is a graph showing an optical transfer function of a glass-plastic hybrid wide-angle lens according to a second embodiment of the present invention.

Fig. 8 is a dot-column diagram graph of a glass-plastic hybrid wide-angle lens according to a second embodiment of the present invention.

FIG. 9 is a low-temperature on-axis defocus plot (-30 ℃ C.; thin line is 20 ℃ C., and thick line is-30 ℃ C.) of a glass-plastic hybrid wide-angle lens according to a second embodiment of the present invention.

FIG. 10 is an on-axis defocus graph (85 ℃ C.; thin line 20 ℃ C., thick line 85 ℃ C.) for the high temperature of the glass-plastic hybrid wide-angle lens in the second embodiment of the present invention.

The reference signs are: the lens comprises a first lens 10, a second lens 11, a third lens 12, a fourth lens 13, a fifth lens 14, a sixth lens 15, a seventh lens 16, flat glass 17, a first lens group 18, a diaphragm 20 and a second lens group 19.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Several embodiments of the invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

First embodiment

Referring to fig. 1, a glass-plastic hybrid wide-angle lens includes, in order from an object side to an image side, a first lens group 18, a stop 20, and a second lens group 19, the first lens group 18 including, from the object side to the stop 20, a first lens 10 having negative power with a convex surface facing the object side and a concave surface facing the stop 20, a second lens 11 having negative power with a convex surface facing the object side and a concave surface facing the stop 20, and a third lens 12 having positive power and both sides being convex; the second lens group 19 includes, from the diaphragm 20 to the image side, a fourth lens 13 having positive power and a convex surface toward the image side, a fifth lens 14 having negative power, a sixth lens 15 having power and a convex surface toward the object side, and a seventh lens 16 having negative power; the surface of the seventh lens element 16 facing the image side is concave at the center and convex at the edge; the sixth lens element 15 and the seventh lens element 16 are aspheric plastic lenses, the second lens element 11, the fourth lens element 13, and the fifth lens element 14 are plastic lenses, and the first lens element 10 and the third lens element are spherical glass lenses. In the invention, the third lens with positive focal power and convex surfaces on both sides and the seventh lens with the surface facing the image side as the center and the concave edge convex surface are arranged, so that the total lens length can be controlled to be less than 15mm under the condition that the target surface chip is enlarged.

The first lens group 18, the diaphragm 20 and the second lens group 19 of the present embodiment are matched with the flat glass 17, and relevant parameters are set to manufacture a glass-plastic hybrid wide-angle lens, and the relevant parameters of each lens are shown in table 1-1.

TABLE 1-1

The aspherical parameters of each lens of this example are shown in tables 1 to 2.

Tables 1 to 2

The aspherical surfaces all satisfy the following equation:

wherein: z represents the distance of the curved surface from the curved surface vertex in the optical axis direction, C represents the curvature of the curved surface vertex, K represents a conic coefficient, h represents the distance from the optical axis to the curved surface, and B, C, D, E, F, G, H represents the curved surface coefficients of fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order, respectively. The following examples are all in accordance with this formula.

In this embodiment, the system focal length f is 2.86mm, FNO is 2.8, the half field angle is 80 degrees, and the total system length TOTR is 11.5 mm. Tables 1 to 3 show the results of conditional calculations.

Tables 1 to 3

Conditional formula (II)	Practice of	Results
			CA₁>0.9CA_i	Established	Conform to
-0.15＜Φ₃+Φ₅＜0.15	0.029	Conform to
			-0.1＜Φ₆+Φ₇＜0.1	-0.0	Conform to
Ιf₄/f₅Ι>1.0	1.3	Conform to
			Total lens length TOTR	11.5	Conform to
The coke leakage amount is less than 5 microns (-20 ℃ -85 ℃)	3 micron	Conform to

Please refer to fig. 2-5 for the optical test results of the present embodiment.

FIG. 2 is a graph showing an optical transfer function of the glass-plastic hybrid wide-angle lens according to the present embodiment;

FIG. 3 is a dot-column diagram of the glass-plastic hybrid wide-angle lens in the present embodiment;

FIG. 4 is a diagram showing the low-temperature on-axis defocus curve (-30 ℃ C.; where the thin line is 20 ℃ C., and the thick line is-30 ℃ C.) of the glass-plastic hybrid wide-angle lens in this example;

FIG. 5 is an on-axis defocus graph (85 ℃ C.; 20 ℃ C. for thin line and 85 ℃ C. for thick line) for the high temperature of the glass-plastic hybrid wide-angle lens of this example.

Second embodiment

Referring to fig. 6, a glass-plastic hybrid wide-angle lens according to a second embodiment of the present invention has a structure substantially the same as that of the lens according to embodiment 1, except that related parameters of each lens in the glass-plastic hybrid lens according to the present embodiment are different, specifically as shown in table 3-1, and aspheric parameters of each lens according to the present embodiment are shown in table 3-2.

TABLE 3-1

TABLE 3-2

The aspherical surfaces all satisfy the following equation:

wherein: z represents the distance of the curved surface from the curved surface vertex in the optical axis direction, C represents the curvature of the curved surface vertex, K represents a conic coefficient, h represents the distance from the optical axis to the curved surface, and B, C, D, E, F, G, H represents the curved surface coefficients of fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order, respectively.

In this embodiment, the system focal length f is 2.84mm, FNO is 2.8, the half field angle is 80 degrees, and the total system length TOTR is 11.0 mm. Tables 3 to 3 show the results of conditional calculations.

Tables 3 to 3

Conditional formula (II)	Practice of	Results
			CA₁>0.9CA_i	Established	Conform to
-0.15＜Φ₃+Φ₅＜0.15	0.05	Conform to
			-0.1＜Φ₆+Φ₇＜0.1	-0.02	Conform to
Ιf₄/f₅Ι>1.0	1.5	Conform to
			Total lens length TOTR	11.0	Conform to
The coke leakage amount is less than 5 microns (-20 ℃ -85 ℃)	3 micron	Conform to

Please refer to fig. 7-10 for the optical test results of the present embodiment.

FIG. 7 is a graph showing an optical transfer function of the glass-plastic hybrid wide-angle lens according to the present embodiment;

FIG. 8 is a dot-column diagram of the glass-plastic hybrid wide-angle lens of the present embodiment;

FIG. 9 is a diagram showing the low-temperature on-axis defocus curve (-30 ℃ C.; where the thin line is 20 ℃ C., and the thick line is-30 ℃ C.) of the glass-plastic hybrid wide-angle lens in this example;

FIG. 10 is an on-axis defocus graph (85 ℃ C.; 20 ℃ C. for thin line and 85 ℃ C. for thick line) for the high temperature of the glass-plastic hybrid wide-angle lens of this example.

In order to achieve the above technical effects, the present invention also needs to satisfy the following conditions:

the conditional expression is satisfied: CA₁>0.9CA_iThe light-transmitting aperture of the first lens can be large enough when the camera looks on the appearance,

the aesthetic property of the equipment is ensured.

The conditional expression is satisfied: -0.15 < phi₃+Φ₅< 0.15 and-0.1 < phi₆+Φ₇Is less than 0.1, and the third lens is a spherical glass lens, even under the condition of using more plastic lenses, the minimal focus running amount of the lens in the temperature range of-30 ℃ to 85 ℃ can be realized, and the embodiment is realized to be less than 5 microns.

The conditional expression is satisfied: i f₄/f₅Ι>1.0, the on-axis resolution can be better lifted.

Conditional formula (II)	First embodiment	Second embodiment	Results
				CA₁>0.9CA_i	Established	Established	Conform to
-0.15＜Φ₃+Φ₅＜0.15	0.029	0.05	Conform to
				-0.1＜Φ₆+Φ₇＜0.1	-0.0	-0.02	Conform to
Ιf₄/f₅Ι>1.0	1.3	1.5	Conform to
				Total lens length TOTR	11.5	11.0	Conform to
The coke leakage amount is less than 5 microns (-20 ℃ -85 ℃)	3 micron	3 micron	Conform to

Compared with the prior art, the invention at least has the following advantages:

(1) the lens can realize low cost due to the use of more plastic lenses;

(2) the lens has the advantages that through limitation on the surface types of some lenses and reasonable power distribution on the whole lens group, the total length of a very short system can be realized, meanwhile, the full-view-field high-definition imaging is realized, and the image quality of more than 4K is realized;

(3) the angle of view of the lens reaches more than 150 degrees.

The above examples only show 2 embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A glass-plastic hybrid wide-angle lens comprising, in order from an object side to an image side, a first lens group (18), a diaphragm (20), and a second lens group (19), characterized in that:

the first lens group (18) includes, from the object side to the stop (20), a first lens (10) having negative power with a convex surface facing the object side and a concave surface facing the stop (20), a second lens (11) having negative power with a convex surface facing the object side and a concave surface facing the stop (20), and a third lens (12) having positive power and convex surfaces on both sides;

the second lens group (19) includes, from the diaphragm (20) to the image side, a fourth lens (13) having positive power and a convex surface toward the image side, a fifth lens (14) having negative power, a sixth lens (15) having power and a convex surface toward the object side, and a seventh lens (16) having negative power; the surface of the seventh lens (16) facing the image side is concave at the center and convex at the edge;

the sixth lens (15) and the seventh lens (16) are aspheric plastic lenses.

2. The glass-plastic hybrid wide-angle lens of claim 1, which is characterized in that:

the conditional expression is satisfied: CA₁>0.9CA_i；

Wherein: CA₁Representing the effective clear aperture, CA, of the first lens (10) close to the object side_iRepresenting the effective imaging plane aperture.

3. The glass-plastic hybrid wide-angle lens of claim 1, which is characterized in that:

the conditional expression is satisfied: -0.15 < phi₃+Φ₅＜0.15；

Wherein: phi₃Represents the power of the third lens (12), phi₅Represents the optical power of the fifth lens (14).

4. The glass-plastic hybrid wide-angle lens of claim 1, which is characterized in that:

the conditional expression is satisfied: -0.1 < phi₆+Φ₇＜0.1，

Wherein phi₆Represents the power, phi, of the sixth lens (15)₇Represents the optical power of the seventh lens (16).

5. The glass-plastic hybrid wide-angle lens of claim 1, which is characterized in that:

the conditional expression is satisfied: i f₄/f₅Ι>1.0；

Wherein f is₄Represents the fourthFocal length f of lens (13)₅Represents the focal length of the fifth lens (14).

6. The glass-plastic hybrid wide-angle lens of claim 1, which is characterized in that: the third lens (12) is a spherical glass lens.