Wide-angle imaging lens
阅读说明:本技术 广角成像镜头 (Wide-angle imaging lens ) 是由 谢典良 于 2018-09-14 设计创作,主要内容包括:本发明公开了一种广角成像镜头,从物侧至像侧沿一光轴依序包括一第一透镜、一第二透镜、一光圈、一第三透镜、一第四透镜及一第五透镜。第一透镜至第五透镜的屈光度依序为负、正、正、负、正。第一透镜的物侧面的光轴附近区域为凹面,第一透镜的像侧面为凹面。第二透镜的物侧面为凸面。第三透镜的物侧面为凸面。第三透镜的像侧面为凸面。第四透镜的物侧面为凹面。第四透镜的像侧面具有一位于光轴附近区域的凹面部。第五透镜的像侧面为凸面。(The invention discloses a wide-angle imaging lens which sequentially comprises a first lens, a second lens, an aperture, a third lens, a fourth lens and a fifth lens from an object side to an image side along an optical axis. Diopters of the first lens to the fifth lens are negative, positive, negative and positive in sequence. The area near the optical axis of the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a concave surface. The object side surface of the second lens is a convex surface. The object side surface of the third lens is a convex surface. The image side surface of the third lens is convex. The object side surface of the fourth lens is a concave surface. The image side surface of the fourth lens is provided with a concave surface part which is positioned in the area near the optical axis. The image side surface of the fifth lens is convex.)
1. A wide-angle imaging lens is characterized by comprising a first lens, a second lens, an aperture, a third lens, a fourth lens and a fifth lens in sequence from an object side to an image side along an optical axis, wherein the first lens to the fifth lens respectively comprise an object side surface facing the object side and allowing imaging light rays to pass through and an image side surface facing the image side and allowing the imaging light rays to pass through, and the lenses with diopter only comprise the five lenses;
the first lens is provided with negative diopter, the area near the optical axis of the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a concave surface;
the second lens has positive diopter, and the object side surface of the second lens is a convex surface;
the third lens element has a positive refractive power, the object-side surface of the third lens element is a convex surface, and the image-side surface of the third lens element is a convex surface;
the fourth lens has negative diopter, the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is provided with a concave surface part positioned in an area near an optical axis; and
the fifth lens element has a positive refractive power, and the image-side surface of the fifth lens element is convex.
2. The wide-angle imaging lens of claim 1, wherein the wide-angle imaging lens conforms to: -0.8 ≦ EFL/R1<0, where EFL is the effective focal length of the wide-angle imaging lens and R1 is the radius of curvature of the object-side surface of the first lens.
3. The wide-angle imaging lens of claim 1, wherein the wide-angle imaging lens conforms to: 0.8 ≦ EFL/f1 ≦ 1.2, where EFL is an effective focal length of the wide-angle imaging lens, f1 is a focal length of the first lens, and | EFL/f1| is an absolute value of EFL/f 1.
4. The wide-angle imaging lens of claim 1, wherein the wide-angle imaging lens conforms to: -3.0 ≦ (R3+ R4)/(R3-R4) ≦ 0.9, where R3 is the radius of curvature of the object-side surface of the second lens and R4 is the radius of curvature of the image-side surface of the second lens.
5. The wide-angle imaging lens of claim 1, wherein a range of an angle of view of the wide-angle imaging lens falls within a range of 130 degrees to 150 degrees.
6. The wide-angle imaging lens according to claim 1, wherein, of the first lens, the second lens, the third lens, the fourth lens and the fifth lens having refractive power, the refractive index of the second lens is equal to or greater than the refractive index of the other lenses having refractive power, and the abbe number of the second lens is equal to or less than the abbe number of the other lenses having refractive power.
7. The wide-angle imaging lens of claim 1,
the object side surface of the first lens is a concave surface and is provided with a concave surface part positioned in the area near the circumference,
the image side surface of the second lens is convex,
the image side surface of the fourth lens is provided with a concave surface part positioned in an area near an optical axis and a convex surface part positioned in an area near the circumference,
the object side surface of the fifth lens is provided with a convex surface part positioned in an area near an optical axis and a concave surface part positioned in an area near the circumference.
8. The wide-angle imaging lens of claim 1,
the object side surface of the first lens is provided with a convex surface part positioned in the area near the circumference,
the image side surface of the second lens is convex,
the image side surface of the fourth lens is provided with a concave surface part positioned in an area near an optical axis and a convex surface part positioned in an area near the circumference,
the object side surface of the fifth lens is provided with a convex surface part positioned in an area near an optical axis and a concave surface part positioned in an area near the circumference.
9. The wide-angle imaging lens of claim 1,
the object side surface of the first lens is a concave surface and is provided with a concave surface part positioned in the area near the circumference,
the image side surface of the second lens is convex,
the image side surface of the fourth lens is a concave surface and is provided with a concave surface part positioned in the area near the circumference,
the object side surface of the fifth lens is a convex surface.
10. The wide-angle imaging lens of claim 1,
the object side surface of the first lens is a concave surface and is provided with a concave surface part positioned in the area near the circumference,
the image side surface of the second lens is a concave surface,
the image side surface of the fourth lens is provided with a concave surface part positioned in an area near an optical axis and a convex surface part positioned in an area near the circumference,
the object side surface of the fifth lens is a concave surface.
Technical Field
The present invention relates to an optical imaging lens, and more particularly to a wide-angle imaging lens.
Background
In recent years, the popularity of mobile phones and digital cameras has led to the development of camera modules, and wide-angle imaging lenses for capturing and recording images are required to be designed to be light, thin, small and compact. However, the wide-angle imaging lens in the present stage generally has a long lens Length (TTL), which is not favorable for thinning the lens. In view of the above problems, it is an endeavor of those skilled in the art to design an imaging lens having a good imaging quality, a short lens length, and a wide angle of view.
Disclosure of Invention
The invention provides a wide-angle imaging lens which has a wide visual angle, a short lens length and good optical quality.
In an embodiment of the present invention, a wide-angle imaging lens includes, in order from an object side to an image side along an optical axis, a first lens element, a second lens element, an aperture stop, a third lens element, a fourth lens element and a fifth lens element. The first lens element to the fifth lens element each include an object-side surface facing the object side and passing the imaging light and an image-side surface facing the image side and passing the imaging light, and the lens elements having refractive power are only the five lens elements. The first lens has a negative refractive power. The area near the optical axis of the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a concave surface. The second lens has a positive refractive power. The object side surface of the second lens is a convex surface. The third lens has a positive refractive power. The object side surface of the third lens is a convex surface. The image side surface of the third lens is convex. The fourth lens has a negative refractive power. The object side surface of the fourth lens is a concave surface. The image side surface of the fourth lens is provided with a concave surface part which is positioned in the area near the optical axis. The fifth lens element has a positive refractive power, and an image-side surface of the fifth lens element is convex.
In an embodiment of the present invention, the wide-angle imaging lens includes: -0.8 ≦ EFL/R1<0, where EFL is the effective focal length of the wide-angle imaging lens and R1 is the radius of curvature of the object side of the first lens.
In an embodiment of the present invention, the wide-angle imaging lens includes: 0.8 ≦ EFL/f1 ≦ 1.2, where EFL is an effective focal length of the wide-angle imaging lens, f1 is a focal length of the first lens, and | EFL/f1| is an absolute value of EFL/
In an embodiment of the present invention, the wide-angle imaging lens includes: -3.0 ≦ (R3+ R4)/(R3-R4) ≦ 0.9, where R3 is the radius of curvature of the object-side surface of the second lens, and R4 is the radius of curvature of the image-side surface of the second lens.
In an embodiment of the invention, a range of the field angle of the wide-angle imaging lens is in a range of 130 degrees to 150 degrees.
In an embodiment of the invention, in the first lens, the second lens, the third lens, the fourth lens and the fifth lens having diopter, the refractive index of the second lens is greater than or equal to the refractive index of the other lenses having diopter, and the abbe number of the second lens is less than or equal to the abbe number of the other lenses having diopter.
In an embodiment of the invention, the object-side surface of the first lens element is concave and has a concave portion located in a region near the circumference. The image side surface of the second lens is convex. The image side surface of the fourth lens is provided with a concave surface part positioned in an area nearby an optical axis and a convex surface part positioned in an area nearby the circumference. The object side surface of the fifth lens is provided with a convex surface part positioned in an area near an optical axis and a concave surface part positioned in an area near the circumference.
In an embodiment of the invention, the object-side surface of the first lens element has a convex surface portion located in a circumferential vicinity. The image side surface of the second lens is convex. The image side surface of the fourth lens is provided with a concave surface part positioned in an area nearby an optical axis and a convex surface part positioned in an area nearby the circumference. The object side surface of the fifth lens is provided with a convex surface part positioned in an area near an optical axis and a concave surface part positioned in an area near the circumference.
In an embodiment of the invention, the object-side surface of the first lens element is concave and has a concave portion located in a region near the circumference. The image side surface of the second lens is convex. The image side surface of the fourth lens is concave and is provided with a concave surface part positioned in the area near the circumference. The object side surface of the fifth lens is a convex surface.
In an embodiment of the invention, the object-side surface of the first lens element is concave and has a concave portion located in a region near the circumference. The image side surface of the second lens is a concave surface. The image side surface of the fourth lens is provided with a concave surface part positioned in an area nearby an optical axis and a convex surface part positioned in an area nearby the circumference. The object side surface of the fifth lens is a concave surface.
Based on the above, the wide-angle imaging lens of the embodiment of the invention has the following beneficial effects: by the concave-convex shape design and arrangement of the object side surface or the image side surface of the lens and the diopter combination of the lens, the wide-angle imaging lens can achieve the effect of wide visual angle, shorter lens length and good imaging quality.
In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.
Drawings
Fig. 1 is a schematic diagram of a wide-angle imaging lens according to a first embodiment of the present invention.
Fig. 2A to 2D are longitudinal spherical aberration diagrams and various aberration diagrams of the first embodiment.
Fig. 3 is a schematic diagram of a wide-angle imaging lens according to a second embodiment of the present invention.
Fig. 4A to 4D are longitudinal spherical aberration diagrams and various aberration diagrams of the second embodiment.
Fig. 5 is a schematic diagram of a wide-angle imaging lens according to a third embodiment of the present invention.
Fig. 6A to 6D are longitudinal spherical aberration diagrams and various aberration diagrams of the third embodiment.
Fig. 7 is a schematic diagram of a wide-angle imaging lens according to a fourth embodiment of the present invention.
Fig. 8A to 8D are longitudinal spherical aberration diagrams and various aberration diagrams of the fourth embodiment.
Wherein, the reference numbers:
0: aperture
1: first lens
2: second lens
3: third lens
4: fourth lens
5: fifth lens element
9: optical filter
11. 21, 31, 41, 51, 91: side of the object
12. 22, 32, 42, 52, 92: image side
112. 114, 122, 124, 222, 224, 412, 414, 422, 424, 512, 514: concave part
113. 211, 213, 221, 223, 311, 313, 321, 323, 423, 511, 513, 521, 523: convex surface part
10: wide-angle imaging lens
100: image plane
Ef1、Ef2: outer edge of optically effective portion
Ei: outer edge of optically inactive portion
I: optical axis
RP1, RP 2: reference plane
Pn: optical null
θ: included angle
Detailed Description
In the present specification, "a lens has a positive refractive power (or a negative refractive power)" means that the refractive power on the optical axis of the lens calculated by the gaussian optical theory is positive (or negative). In the imaging lens group, each lens is radially symmetrical with each other by taking the optical axis as a symmetry axis. Each lens has an object side surface and an image side surface opposite to the object side surface. The object-side surface and the image-side surface define surfaces of the lens through which imaging light rays pass, wherein the imaging light rays include a chief ray (Chief ray) and a marginal ray (marginalray). The object side surface (or image side surface) has an optical axis vicinity region and a circumference vicinity region connected to and surrounding the optical axis vicinity region. The region near the optical axis is a region on the optical axis through which the imaging light passes. The peripheral vicinity is a region through which the marginal ray passes.
"a region of a surface (an object-side surface or an image-side surface) of the lens near the optical axis (or a region near the circumference thereof) is a convex surface or a concave surface" may be determined on the image side or the object side by an intersection point of a ray (or a ray extension line) passing through the region in parallel with the optical axis (a ray focus determination method). For example, when the light passes through the region, the light is focused toward the image side, and the focal point of the optical axis is located at the image side, the region is a convex surface portion. On the contrary, if the light passes through the certain region, the light diverges, and the extension line and the focal point of the optical axis are on the object side. The determination of the surface shape of the surface in the region near the optical axis can be made according to the determination manner of a person skilled in the art, that is, the determination of the unevenness is made by the positive or negative of the R value (referring to the curvature radius of the paraxial region). Regarding the object side, when the R value is positive, it is determined that the object side is convex in the area near the optical axis, that is, the object side has a convex portion in the area near the optical axis; when the value of R is negative, it is determined that the object side surface has a concave surface in the region near the optical axis, that is, the object side surface has a concave surface portion in the region near the optical axis. Regarding the image side surface, when the R value is positive, it is determined that the image side surface is concave in the region near the optical axis, that is, the image side surface has a concave portion in the region near the optical axis; when the R value is negative, it is determined that the image side surface is convex in the region near the optical axis, that is, the image side surface has a convex portion in the region near the optical axis.
A surface (object side or image side) of the lens may have more than one convex portion, more than one concave portion, or a combination of both. When the surface has a convex surface portion and a concave surface portion, the surface has an inflection point. The inflection point is the transition point between the convex surface portion and the concave surface portion. That is, the surface is concave by convex, or convex by concave at points of reverse curvature. On the other hand, when the surface has only a convex surface portion or only a concave surface portion, the surface does not have an inflection point.
Referring to fig. 1, a wide-
The
The
The
The
The
The
The
In the wide-
Other detailed optical data for the first embodiment are shown in table one. In table I, a distance (mm) between the object-
In the present embodiment, the object-
in the formula (1), Y is a distance between a point on the aspherical surface curve and the optical axis I. Z is the depth of the aspheric surface. R is the radius of curvature of the lens surface near the optical axis I. K is the cone constant (conc constant). A. theiAre the i-th order aspheric coefficients.
The aspheric coefficients of the object-
Watch two
The relationship between the important parameters in the wide-
Effective Focal Length (EFL)
0.40 mm (mm)
Half field angle (HFOV)
71.0 degree
Lens full length (TTL)
2.328 mm (mm)
Aperture value (f-number)
5.00
EFL/R1
-0.08
|EFL/f1|
0.88
(R3+R4)/(R3-R4)
-0.82
Watch III
The wide-
Referring to fig. 2A to 2D, the diagram of fig. 2A illustrates the Longitudinal Spherical Aberration (Longitudinal Spherical Aberration) of the first embodiment at the
Referring to fig. 2A again, the curves formed by each wavelength are very close and close to the middle, which shows that the off-axis light beams with different heights of each wavelength are all concentrated near the imaging point, and the deviation of the off-axis light beams with different heights is controlled within the range of ± 0.01 mm as can be seen from the deviation of the curve of each wavelength, so that the spherical aberration of the same wavelength is obviously improved in the first embodiment.
In the two field curvature aberration diagrams of fig. 2B and fig. 2C, the variation of the focal length of 587 nm wavelength over the entire field of view is within ± 0.01 mm, which illustrates that the first embodiment can effectively eliminate the aberration. The distortion aberration diagram of fig. 2D shows that the distortion aberration of the first embodiment is maintained within a range of ± 50%, which indicates that the distortion aberration of the first embodiment meets the requirement of the optical system for image quality, and thus the first embodiment can provide good image quality under the condition that the total lens length is shortened to about 2.328 mm compared with the conventional optical lens.
Fig. 3 is a schematic diagram of a wide-angle imaging lens according to a second embodiment of the present invention. Fig. 4A to 4D are longitudinal spherical aberration diagrams and various aberration diagrams of the second embodiment. Referring to fig. 3, a second embodiment of the wide-
Other detailed optical data for the second embodiment are shown in table four below. The aspheric coefficients of the terms in equation (1) for the object-
watch four
Watch five
The relationship between the important parameters in the wide-
Effective Focal Length (EFL)
0.38 mm (mm)
Half field angle (HFOV)
70.0 degree
Lens full length (TTL)
2.650 mm (mm)
Aperture value (f-number)
4.50
EFL/R1
-0.71
|EFL/f1|
0.81
(R3+R4)/(R3-R4)
0.76
Watch six
In the diagram of FIG. 4A, the deviation of the imaging points of the off-axis light rays with different heights is controlled within + -0.025 mm. In the two graphs of field curvature aberration of fig. 4B and 4C, the variation of focal length of three representative wavelengths in the entire field of view is within ± 0.025 mm. The distortion aberration diagram of FIG. 4D shows that the distortion aberration of the second embodiment is maintained within a range of + -40%. Accordingly, the wide-
Fig. 5 is a schematic diagram of a wide-angle imaging lens according to a third embodiment of the present invention. Fig. 6A to 6D are longitudinal spherical aberration diagrams and various aberration diagrams of the third embodiment. Referring to fig. 5, a third embodiment of the wide-
Other detailed optical data of the third embodiment are shown in table seven below. Each aspheric coefficient of the
Watch seven
Table eight
The relationship between the important parameters in the wide-
Effective Focal Length (EFL)
0.47 mm (mm)
Half field angle (HFOV)
70.0 degree
Lens full length (TTL)
2.483 mm (mm)
Aperture value (f-number)
4.40
EFL/R1
-0.67
|EFL/f1|
0.99
(R3+R4)/(R3-R4)
0.90
Watch nine
In the diagram of fig. 6A, the deviation of the imaging points of the off-axis light rays with different heights is controlled within ± 0.01 mm. In the two graphs of field curvature aberration of fig. 6B and 6C, the variation of focal length of the three representative wavelengths over the entire field of view falls within ± 0.01 mm. The distortion aberration diagram of FIG. 6D shows that the distortion aberration of the third embodiment is maintained within a range of + -50%. Accordingly, the wide-
Fig. 7 is a schematic diagram of a wide-angle imaging lens according to a fourth embodiment of the present invention. Fig. 8A to 8D are longitudinal spherical aberration diagrams and various aberration diagrams of the fourth embodiment. Referring to fig. 7, a fourth embodiment of the wide-angle
Other detailed optical data of the fourth embodiment are shown in the following table ten. The aspheric coefficients of the terms in equation (1) for the object-
Watch ten
Surface of
K
A4
A6
A8
11
-9.9000E+01
4.3004E-01
-2.0093E+00
1.1862E+00
12
-1.1672E+00
-2.5559E+00
9.7652E+01
8.9671E+01
21
-3.2680E+01
4.6320E+00
-1.5628E+01
-2.0898E+02
22
4.0674E+01
3.2007E-01
-1.6251E+02
3.5683E+04
31
3.2996E+00
-5.0175E+00
8.1882E+01
-7.7727E+03
32
-9.7119E+00
-2.1234E+01
8.4775E+02
-2.2295E+04
41
-1.6901E+01
-1.2895E+01
5.1420E+02
-1.9108E+04
42
-9.9000E+01
-2.8205E+00
-9.9542E+01
4.4210E+03
51
8.5999E+01
1.3451E+01
-6.3835E+02
1.4257E+04
52
7.7560E-01
1.5730E+01
-1.8597E+02
1.2508E+03
Noodle
A10
A12
A14
A16
11
0.0000E+00
0.0000E+00
0.0000E+00
0.0000E+00
12
-8.3965E+03
0.0000E+00
0.0000E+00
0.0000E+00
21
5.7819E+03
-5.3084E+04
0.0000E+00
0.0000E+00
22
-2.5561E+06
7.0932E+07
0.0000E+00
0.0000E+00
31
2.8162E+05
0.0000E+00
0.0000E+00
0.0000E+00
32
3.6267E+05
0.0000E+00
0.0000E+00
0.0000E+00
41
3.3218E+05
-1.5510E+06
0.0000E+00
0.0000E+00
42
-6.1367E+04
2.6939E+05
0.0000E+00
0.0000E+00
51
-1.6621E+05
1.0103E+06
-2.8394E+06
0.0000E+00
52
-8.3141E+01
-3.7712E+04
1.2816E+05
0.0000E+00
Watch eleven
The relationship between the important parameters in the wide-
Watch twelve
In fig. 8A, the deviation of the imaging point of the off-axis light rays with different heights is controlled within ± 0.025 mm. In the two graphs of field curvature aberration of fig. 8B and 8C, the variation of focal length of the three representative wavelengths over the entire field of view falls within ± 0.04 mm. The distortion aberration diagram of FIG. 8D shows that the distortion aberration of the fourth embodiment is maintained within + -45%. Accordingly, the wide-
The wide-
the
The refractive index of the
The
In addition, in view of the unpredictability of the optical system design, under the framework of the present invention, at least one of the following conditional expressions is satisfied to preferably improve the imaging quality of the system and to improve the drawbacks of the prior art.
In the above-described embodiment, the wide-
In the above-described embodiment, the wide-
In the above-described embodiment, the wide-
In the above-described embodiment, the range of the Angle of View (Angle of View) of the wide-
Based on the above, the wide-angle imaging lens of the embodiment of the invention has the following beneficial effects: by the concave-convex shape design and arrangement of the object side surface or the image side surface of the lens and the diopter combination of the lens, the wide-angle imaging lens can achieve the effect of wide visual angle, shorter lens length and good imaging quality.
Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.
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