Wide-angle high-resolution lens

Abstract

The present invention relates to a wide-angle high-resolution lens, the technical key points of which are that, along the optical axis, from the object side to the image side, it includes: a first lens P1 with a concave surface on the object side and negative refractive power, a second lens P2 with a convex surface on the object side and positive refractive power, a third lens P3 with convex surfaces on both the object side and the image side and positive refractive power, a fourth lens P4 with a convex surface on the image side and negative refractive power, and a fifth lens P5 with a convex surface on the object side and positive refractive power at the paraxial part; an aperture is arranged between the second lens P2 and the third lens P3, at least one surface on the object and image sides of the fourth lens P4 is an aspherical surface, at least one surface on the object and image sides of the fifth lens P5 is an aspherical surface, and the first, second, third, fourth, and fifth lenses P1, P2, P3, P4, and P5 are all aspherical plastic lenses. By adopting the optical system composed of the above five-piece aspherical plastic lenses, the characteristics of high resolution and large field of view are achieved.

Description

Technical Field

[0001] The present invention relates to an optical system, in particular to a wide-angle high-resolution lens, which is suitable for rear lenses of high-pixel mobile phones such as full-screen, notch-screen, and double-sided screen. Background Art

[0002] With the continuous innovation of smartphone camera functions and shooting modes, people's demand for the shooting function of the rear camera of the mobile phone is no longer limited to high resolution and large aperture, but is developing in a more novel direction - wide-angle.

[0003] With the ever-changing development trend of the electronics market, in addition to high requirements for high resolution, large aperture and ultra-thinness, a wide field of view is also a development direction worthy of attention. The field of view of mainstream lenses on the market is generally between 70° and 80°. In order to meet the practical needs of the electronics market, it is urgent to design a mobile phone lens with a wide field of view on the basis of meeting high resolution, large aperture and ultra-thinness. Summary of the invention

[0004] The purpose of the present invention is to provide a wide-angle high-resolution lens that meets the current market demand, adopting an optical system composed of five aspherical plastic lenses to achieve the characteristics of high resolution and large field of view.

[0005] The technical solution of the present invention is:

[0006] A wide-angle high-resolution lens, the technical key points of which are that, along the optical axis, from the object side to the image side, it includes: a first lens P1 whose object side surface is concave and has negative refractive power, a second lens P2 whose object side surface is convex and has positive refractive power, a third lens P3 whose object side surface and image side surface are both convex and have positive refractive power, a fourth lens P4 whose image side surface is convex and has negative refractive power, and a fifth lens P5 whose object side surface is convex at the paraxial part and has positive refractive power; an aperture stop is arranged between the second lens P2 and the third lens P3, at least one of the object and image sides of the fourth lens P4 is an aspherical surface, at least one of the object and image sides of the fifth lens P5 is an aspherical surface, the first, second, third, fourth, fifth lenses P1, P2, P3, P4, P5 are all aspherical plastic lenses, wherein the refractive index N of the material of the second lens P2 is 2 and the refractive index N of the material of the fourth lens P4 4 Both are greater than 1.66.

[0007] The wide-angle high-resolution lens mentioned above also satisfies the following conditional formula:

[0008] TTL / ImgH<2

[0009] Wherein, TTL is the total optical length of the wide-angle high-resolution lens, and ImgH is half of the diagonal length of the effective pixel area on the imaging surface of the wide-angle high-resolution lens. This condition is used to limit the total length and image height of the optical system, which helps to shorten the lens length and improve the lens quality.

[0010] The wide-angle high-resolution lens mentioned above also satisfies the following conditional formula:

[0011] 0.6 <Efl / Yh<0.9

[0012] Wherein, Efl is the effective focal length of the wide-angle high-resolution lens, and Yh is the maximum image height of the wide-angle high-resolution lens. This condition is used to limit the focal length of the lens, which helps to control the system aberration and is easy to process.

[0013] The wide-angle high-resolution lens mentioned above also satisfies the following conditional formula:

[0014] -13 <R1 / R2<-11

[0015] Among them, R1 and R2 are the curvature radii of the object side and image side of the first lens P1 respectively. This condition is used to limit the shape and focal length of the first lens, which helps to control the system aberration and makes the first lens easier to process and improve the imaging quality.

[0016] The wide-angle high-resolution lens mentioned above also satisfies the following conditional formula:

[0017] 5.5 <CT1 / CT2<12.5

[0018] 7 <ET1 / ET2<9.5

[0019] Among them, CT1 is the center thickness of the third lens P3, CT2 is the air spacing between the third lens P3 and the fourth lens P4 on the optical axis, ET1 is the edge thickness of the third lens P3, and ET2 is the edge air spacing from the third lens P3 to the fourth lens P4. This condition is used to limit the thickness of the third lens and the relationship between the gap between the third lens and the fourth lens, so that the third lens is easy to process and assemble, and the imaging quality is improved.

[0020] The wide-angle high-resolution lens mentioned above also satisfies the following conditional formula:

[0021] |SAG41 / SD41|≧0.44;

[0022] Wherein, SAG41 is the sag height of the object side surface of the fourth lens P4, and SD41 is the maximum effective radius of the object side surface of the fourth lens P4. This condition is used to limit the shape and aperture size of the fourth lens, making the fourth lens more compact.

[0023] In the wide-angle high-resolution lens, the image side surface of the first lens P1 is a concave surface. Satisfying this formula can reasonably allocate the shape and focal length of the first lens, help control system aberrations, facilitate processing, and improve imaging quality.

[0024] The wide-angle high-resolution lens mentioned above also satisfies the following conditional formula:

[0025] 0.37 <R3 / R4<2

[0026] Among them, R3 and R4 are the curvature radii of the object side and image side of the second lens P2 respectively. This condition is used to limit the shape and focal length of the second lens, which helps to control the system aberration, and makes the second lens easy to process and improves the imaging quality.

[0027] In the wide-angle high-resolution lens, the first, second, third, fourth and fifth lenses P1, P2, P3, P4 and P5 are all made of even-order aspherical plastic lenses, and the aspherical coefficients satisfy the following equation:

[0028] Z=cy 2 / [1+{1-(1+k)c 2 y 2} +1 / 2 ]+A 4 y 4 +A 6 y 6 +A 8 y 8 +A 10 y 10 +A 12 y 12 +A 14 y 14

[0029] Among them, Z is the aspheric surface sag, c is the aspheric surface paraxial curvature, y is the lens aperture, k is the cone coefficient, A 4 is the fourth-order aspheric coefficient, A 6 is the sixth-order aspheric coefficient, A 8 is the 8th-order aspheric coefficient, A 10 is the 10th-order aspheric coefficient, A 12 is the 12th-order aspheric coefficient, A 14 is the 14th-order aspheric coefficient.

[0030] The beneficial effects of the present invention are:

[0031] The optical system composed of the above five aspherical plastic lenses achieves a bright lens with a field of view of 120 degrees, an optical length of less than 4.57mm, and an aperture value of F2.2. It also performs well in darker environments, with a maximum image circle of When the pixel size of the matching "4H7" Sensor is 1.12um, the pixel can reach 8 million. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a two-dimensional diagram of the lens in Example 1;

[0033] Figure 2 is the optical path diagram of the lens in Example 1;

[0034] Figure 3 is a graph of the MTF transfer function (optical transfer function) of the lens in Example 1;

[0035] Figure 4 is the defocus curve of the lens in Example 1;

[0036] Figure 5 are the astigmatism field curvature characteristic curve and the optical distortion curve of the lens in Example 1;

[0037] Figure 6 is the optical path diagram of the lens in Example 2;

[0038] Figure 7 is a graph of the MTF transfer function (optical transfer function) of the lens in Example 2;

[0039] Figure 8 is the defocus curve of the lens in Example 3;

[0040] Fig. 9 3 are the astigmatism field curvature characteristic curve and the optical distortion curve of the lens in Example 3. DETAILED DESCRIPTION

[0041] Example 1

[0042] like Figure 1 , Figure 2 As shown, the wide-angle high-resolution lens includes, in order from the object side to the image side along the optical axis: a first lens P1 with concave surfaces on both the object and image sides and negative refractive power; a second lens P2 with a convex surface on the object side and a concave surface on the image side and positive refractive power; a third lens P3 with convex surfaces on both the object side and the image side and positive refractive power; a fourth lens P4 with a concave surface on the object side and a convex surface on the image side and negative refractive power; and a fifth lens P5 with a convex surface at the near-axis portion of the object side and a concave surface at the near-axis portion of the image side and positive refractive power. A stop is provided between the second lens P2 and the third lens P3. In this embodiment, both the object and image sides of the fourth lens P4 and both the object and image sides of the fifth lens P5 are aspherical.

[0043] The wide-angle high-resolution lens also satisfies the following conditional formula:

[0044] TTL / ImgH<2

[0045] 0.6 <Efl / Yh<0.9

[0046] -13 <R1 / R2<-11

[0047] 5.5 <CT1 / CT2<12.5

[0048] 7 <ET1 / ET2<9.5

[0049] |SAG41 / SD41|≧0.44;

[0050] 0.37 <R3 / R4<2

[0051] Among them, TTL is the total optical length of the wide-angle high-resolution lens, ImgH is half of the diagonal length of the effective pixel area on the imaging surface of the wide-angle high-resolution lens; Efl is the effective focal length of the wide-angle high-resolution lens, and Yh is the maximum image height of the wide-angle high-resolution lens; R1 and R2 are the curvature radii of the object side and the image side of the first lens P1, respectively; CT1 is the center thickness of the third lens P3, CT2 is the air spacing between the third lens P3 and the fourth lens P4 on the optical axis, ET1 is the edge thickness of the third lens P3, and ET2 is the edge air spacing from the third lens P3 to the fourth lens P4; SAG41 is the sag height of the object side of the fourth lens P4, and SD41 is the maximum effective radius of the object side of the fourth lens P4; R3 and R4 are the curvature radii of the object side and the image side of the second lens P2, respectively.

[0052] The first, second, third, fourth and fifth lenses P1, P2, P3, P4 and P5 of the wide-angle high-resolution lens are all made of even-order aspheric plastic lenses, and the aspheric coefficients satisfy the following equation:

[0053] Z=cy 2 / [1+{1-(1+k)c 2 y 2} +1 / 2 ]+A 4 y 4 +A 6 y 6 +A 8 y 8 +A 10 y 10 +A 12 y 12 +A 14 y 14

[0054] Among them, Z is the aspheric surface sag, c is the aspheric surface paraxial curvature, y is the lens aperture, k is the cone coefficient, A 4 is the fourth-order aspheric coefficient, A 6is the sixth-order aspheric coefficient, A 8 is the 8th-order aspheric coefficient, A 10 is the 10th-order aspheric coefficient, A 12 is the 12th-order aspheric coefficient, A 14 is the 14th-order aspheric coefficient.

[0055] In this embodiment, the design parameters of the lens are shown in Table 1(a) and Table 1(b).

[0056] Table 1(a)

[0057]

[0058]

[0059] Table 1(b)

[0060]

[0061]

[0062] In this embodiment, the total optical length TTL is 4.57 mm, and TTL / ImgH is 1.987;

[0063] Efl is 1.525, and the value of Efl / Yh is 0.875;

[0064] The value of R1 / R2 is -12.9, and the value of R3 / R4 is 0.377;

[0065] CT1 is 1.145, CT2 is 0.0943, and the value of CT1 / CT2 is 12.1;

[0066] ET1 is 0.72, ET2 is 0.077, and the value of ET1 / ET2 is 9.35;

[0067] SAG41 is 0.25, SD41 is 0.56, and the value of |SAG41 / SD41| is 0.446.

[0068] In this embodiment, an optical system with a full field angle of 120° and an aperture FNO. value of 2.2 is finally realized.

[0069] like Figure 1 , Figure 2 As shown, the lens shape of the optical system is good, which is convenient for molding and production; and the lens spacing is reasonable, which is convenient for subsequent structural design.

[0070] like Figure 3As shown, it is the MTF transfer function curve (optical transfer function) of the wide-angle lens in this embodiment, which can comprehensively reflect the imaging quality of the system. The smoother the curve shape and the higher the height relative to the X-axis, the better the imaging quality of the system. The wide-angle lens of the present invention has higher clarity.

[0071] like Figure 4 , which are the defocus curves of the wide-angle lens in this embodiment, respectively represent the optical performance and defocus amount of 0 field of view, 0.4 field of view, 0.6 field of view, 0.8 field of view and 1.0 field of view. The peak of the defocus curve of the wide-angle lens of the present invention is close to the center point, indicating good optical performance and small field curvature.

[0072] like Figure 5 As shown in FIG. 1 , the astigmatism field curvature characteristic curve and the optical distortion curve of the wide-angle lens in this embodiment are shown. The field curvature of the wide-angle lens is well corrected. The imaging does not show edge blur. In the distortion curve, the closer the curve is to the Y axis, the smaller the distortion is and the better the imaging quality is. However, for the wide-angle lens, the edge distortion will be relatively large.

[0073] Example 2

[0074] In this embodiment, the structure and configuration of the lens are the same as those in Embodiment 1. For specific design parameters, please refer to Table 2(a) and Table 2(b).

[0075] Table 2(a)

[0076]

[0077]

[0078] Table 2(b)

[0079]

[0080]

[0081] In this embodiment, the total optical length TTL is 4.57 mm, and TTL / ImgH is 1.87;

[0082] Efl is 1.525, and the value of Efl / Yh is 0.625;

[0083] The value of R1 / R2 is -11.18, and the value of R3 / R4 is 1.86;

[0084] CT1 is 1.074, and the value of CT1 / CT2 is 5.72;

[0085] ET1 is 0.69, and the value of ET1 / ET2 is 7.18;

[0086] SAG41 is 0.235, SD41 is 0.52, and the value of |SAG41 / SD41| is 0.45.

[0087] In this embodiment, an optical system with a full field angle of 120° and an aperture FNO. value of 2.2 is finally realized.

[0088] like Figure 6 As shown, the lens shape of the optical system is good, which is convenient for molding and production; and the lens spacing is reasonable, which is convenient for subsequent structural design.

[0089] like Figure 7 As shown, it is the MTF transfer function curve (optical transfer function) of the wide-angle lens in this embodiment, which can comprehensively reflect the imaging quality of the system. The smoother the curve shape and the higher the height relative to the X-axis, the better the imaging quality of the system. The wide-angle lens of the present invention has higher clarity.

[0090] like Figure 8 , which are the defocus curves of the wide-angle lens in this embodiment, respectively represent the optical performance and defocus amount of 0 field of view, 0.4 field of view, 0.6 field of view, 0.8 field of view and 1.0 field of view. The peak of the defocus curve of the wide-angle lens of the present invention is close to the center point, indicating good optical performance and small field curvature.

[0091] like Fig. 9 As shown in FIG. 1 , the astigmatism field curvature characteristic curve and the optical distortion curve of the wide-angle lens in this embodiment are shown. The field curvature of the wide-angle lens is well corrected. The imaging does not show edge blur. In the distortion curve, the closer the curve is to the Y axis, the smaller the distortion is and the better the imaging quality is. However, for the wide-angle lens, the edge distortion will be relatively larger.

Claims

1. A wide-angle high-resolution lens, characterized in that: The invention is composed of five lenses, which are: a first lens P1 with a concave surface on the object side and negative refractive power, a second lens P2 with a convex surface on the object side and positive refractive power, a third lens P3 with convex surfaces on both the object side and the image side and positive refractive power, a fourth lens P4 with a convex surface on the image side and negative refractive power, and a fifth lens P5 with a convex surface on the object side and positive refractive power at the paraxial part; the aperture is arranged between the second lens P2 and the third lens P3, at least one of the object and image sides of the fourth lens P4 is an aspherical surface, at least one of the object and image sides of the fifth lens P5 is an aspherical surface, the first, second, third, fourth, fifth lenses P1, P2, P3, P4, P5 are all aspherical plastic lenses, wherein the refractive index N2 of the material of the second lens P2 and the refractive index N4 of the material of the fourth lens P4 are both greater than 1.66, and the wide-angle high-resolution lens also satisfies the following conditional formula: TTL / ImgH <2 0.6< Efl / Yh < 0.9 -13< R1 / R2<-11 5.5 <CT1 / CT2 <12.5 7 <ET1 / ET2 <9.5 |SAG41 / SD41||≥0.44 0.37< R3 / R4<2 Wherein, TTL is the total optical length of the wide-angle high-resolution lens, ImgH is half of the diagonal length of the effective pixel area on the imaging plane of the wide-angle high-resolution lens; Efl is the effective focal length of the wide-angle high-resolution lens, and Yh is the maximum image height of the wide-angle high-resolution lens; R1 and R2 are the curvature radii of the object side and the image side of the first lens P1, respectively; CT1 is the center thickness of the third lens P3, CT2 is the air spacing between the third lens P3 and the fourth lens P4 on the optical axis, ET1 is the edge thickness of the third lens P3, and ET2 is the edge air spacing from the third lens P3 to the fourth lens P4; SAG41 is the sag height of the object side of the fourth lens P4, and SD41 is the maximum effective radius of the object side of the fourth lens P4; R3 and R4 are the curvature radii of the object side and the image side of the second lens P2, respectively.

2. The wide-angle high-resolution lens according to claim 1, characterized in that: The image side surface of the first lens P1 is a concave surface.

3. The wide-angle high-resolution lens according to claim 1, characterized in that: The first, second, third, fourth and fifth lenses P1, P2, P3, P4 and P5 are all made of even-order aspheric plastic lenses, and the aspheric coefficients satisfy the following equation: Z = cy 2 / [1+ {1-(1+k)c 2 and 2 } ＋1 / 2 ]+A4y 4 +A6y 6 +A8y 8 +A 10 and 10 + A 12 and 12 + A 14 and 14 Among them, Z is the aspheric surface sag, c is the aspheric surface paraxial curvature, y is the lens aperture, k is the cone coefficient, A4 is the 4th aspheric surface coefficient, A6 is the 6th aspheric surface coefficient, A8 is the 8th aspheric surface coefficient, A 10 is the 10th-order aspheric coefficient, A 12 is the 12th-order aspheric coefficient, A 14 is the 14th-order aspheric coefficient.

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