CN104570295A - Large aperture low sensitivity optical lens assembly - Google Patents

Abstract

The invention relates to a large-aperture low-sensitivity optical lens assembly which comprises a first lens, a second lens and a third lens, wherein the first lens has positive focal power, and the image side surface is a convex surface; a second lens having a negative focal power and a concave object-side surface; a third lens having an aspherical surface and having a positive refractive power; the fourth lens element has a concave object-side surface and both object-side and image-side surfaces thereof are aspheric; the lens assembly satisfies the following relation: F1/TTL is more than 0.3 and less than 1.0; F/TTL is more than 0.7 and less than 1.3; D3/D2 < 3. By means of the structure, under the condition that specific conditions are met, the sensitivity of the system is favorably reduced, the peripheral resolution and illumination are improved, and the imaging effect is improved.

Description

Large aperture low sensitivity optical lens assembly

technical field

The invention relates to the technical field of optical lenses, in particular to a large aperture low-sensitivity optical lens assembly.

Background technique

Today, with the rapid development of science and technology, the mobile phone, as a portable communication tool, is not limited to its basic call function, and the camera and photography function has become one of the important indicators for evaluating the overall performance of a mobile phone. Since the domestic 8-megapixel mobile phone lens was developed and produced in 2010, the lens structure composed of four aspheric resin lenses has become the mainstream of the market. Compared with the immature 13-megapixel lens, the 8-megapixel lens has more mature imaging technology and higher cost performance.

Existing lenses are mostly made of plastic, and some manufacturing defects and alignment errors in the actual production process can easily affect the quality of high-pixel lenses, resulting in low production yields. How to improve the imaging effect of the 8-megapixel lens and reduce the sensitivity of the lens components so as to improve the production yield is a topic to be studied by technicians in this field.

Contents of the invention

In order to solve the above problems, the present invention provides a large-aperture low-sensitivity optical lens assembly, which is provided with an inflection point on the fourth lens, which can more effectively suppress the angle at which light from the off-axis field of view is incident on the photosensitive element, and can further The aberration of the off-axis field of view can be accurately corrected, and the peripheral resolution and illumination can be improved; the optimized parameter design helps to correct field curvature and chromatic aberration of magnification, and can effectively reduce the sensitivity of lens components.

The technical solution adopted in the present invention is: a large aperture low-sensitivity optical lens assembly, including a first lens, a second lens, a third lens, a fourth lens, a filter and a lens arranged in sequence from the object side to the image side The diaphragm arranged on the object side of the first lens, the first lens has positive refractive power, and the image side is convex; the second lens has negative refractive power, and the object side is concave; the third The lens has an aspherical surface and has positive refractive power; the object side of the fourth lens is concave, and both the object side and the image side are aspherical; the lens assembly, the first lens, the second lens, the third lens, and the fourth lens Satisfy the following relations: 0.3<F1/TTL<1.0; 0.7<F/TTL<1.3; D3/D2<3; -1<R7/f<-10; -1<R2/R1<-3; among them, F is the focal length of the lens assembly; F1 is the focal length of the first lens; D2 is the thickness of the second lens on the optical axis; D3 is the thickness of the third lens on the optical axis; R1 is the thickness of the first lens A radius of curvature of the object-side surface of a lens; R2 is the radius of curvature of the image-side surface of the first lens; R7 is the radius of curvature of the object-side surface of the fourth lens; TTL is the total length of the lens assembly.

A further improvement to the above technical solution is that the second lens satisfies the following relationship: 1.5<(R4-R3)/(R4+R3)<6.5, where R3 is the radius of curvature of the object-side surface of the second lens; R4 is the radius of curvature of the image-side surface of the second lens.

The present invention also adopts the following technical scheme: a large-aperture low-sensitivity optical lens assembly, including a first lens, a second lens, a third lens, a fourth lens, an optical filter and a device arranged in sequence from the object side to the image side In the diaphragm between the first lens and the second lens, the first lens has positive power, and the image side is convex; the second lens has negative power, and the object side is concave; The third lens has an aspheric surface and has positive refractive power; the object side of the fourth lens is concave, and both the object side and the image side are aspherical; the lens assembly, the first lens, the second lens, the third lens, The fourth lens satisfies the following relationship: 0.3<F1/TTL<1.0; 0.7<F/TTL<1.3; D3/D2<3; 0.5<(R2-R1)/(R2+R1)<4.5; wherein, F is The focal length of the lens assembly; F1 is the focal length of the first lens; D2 is the thickness of the second lens on the optical axis; D3 is the thickness of the third lens on the optical axis; R1 is the thickness of the first lens The radius of curvature of the object-side surface of the lens; R2 is the radius of curvature of the image-side surface of the first lens; TTL is the total length of the lens assembly.

A further improvement to the above technical solution is that the first lens, the second lens, and the third lens satisfy the following relationship: 4<(Vd1+Vd3)/Vd2<6, where Vd1 is the Abbe number of the first lens; Vd2 is the Abbe number of the second lens; Vd3 is the Abbe number of the third lens.

A further improvement to the above technical solution is that the first lens and the second lens satisfy the following relationship: Vd1>50, Vd2<30; where Vd1 is the Abbe number of the first lens; Vd2 is the Abbe number of the second lens number.

A further improvement to the above technical solution is that the first lens and the second lens satisfy the following relationship: 0.1<n2-n1<0.25; where n1 and n2 are the refractive indices of the first lens and the second lens respectively.

Preferably, the central thickness of the first lens is 0.521-0.839 mm, the central thickness of the second lens is 0.386-0.628 mm, the central thickness of the third lens is 0.665-0.769 mm; the fourth lens The center thickness is 0.446 ~ 0.643mm.

Compared with the prior art, the large-aperture low-sensitivity optical lens assembly of the present invention has the following beneficial effects:

1) The present invention is a 4P 1/4″ wide-angle large-aperture mobile phone lens, with compact structure and reasonable focal power distribution, so that the total optical length of the lens assembly is short, the imaging quality is high, and the tolerance sensitivity is low; four pieces are selected Aspherical plastic lens material not only reduces lens cost but also ensures high production yield.

2) There is an inflection point on the fourth lens, which can more effectively suppress the angle of light incident on the photosensitive element in the off-axis field of view, further correct the aberration of the off-axis field of view, and improve the peripheral resolution and illuminance; optimized Parameter design helps to correct field curvature and chromatic aberration of magnification, while effectively reducing the sensitivity of lens components.

3) The optical lens has the characteristics of high resolution, coupled with the design of 2.2 super large aperture, aiming at the current high-pixel camera phone, it can increase the amount of light entering the shooting process, ensure the brightness of the shooting picture, and effectively improve the ability of night shooting. It can also guarantee a certain imaging quality in a dark environment; the design above 75 degrees meets the wide-angle requirements and enables the mobile phone to have a larger shooting range.

4) The optical distortion of the optical lens assembly is less than 1.5%, the field curvature is less than 0.1mm, the distortion of the imaging picture is small, and the definition is high.

Description of drawings

FIG. 1 is a schematic structural view of a large-aperture low-sensitivity optical lens assembly according to Embodiment 1 of the present invention;

Fig. 2 is the field curvature and distortion curve of the large aperture low-sensitivity optical lens assembly in Embodiment 1 of the present invention;

Fig. 3 is the spherical aberration curve of the optical lens assembly with large aperture and low sensitivity in Embodiment 1 of the present invention;

4 is a schematic structural view of a large aperture low-sensitivity optical lens assembly according to Embodiment 2 of the present invention;

Fig. 5 is the field curvature and distortion curve of the large aperture low-sensitivity optical lens assembly of Embodiment 2 of the present invention;

Fig. 6 is the spherical aberration curve of the large aperture low-sensitivity optical lens assembly of Embodiment 2 of the present invention;

7 is a schematic structural view of a large aperture low-sensitivity optical lens assembly according to Embodiment 3 of the present invention;

Fig. 8 is the field curvature and distortion curve of the large aperture low-sensitivity optical lens assembly according to Embodiment 3 of the present invention;

Fig. 9 is the spherical aberration curve of the optical lens assembly with large aperture and low sensitivity in Embodiment 3 of the present invention;

10 is a schematic structural view of a large aperture low-sensitivity optical lens assembly according to Embodiment 4 of the present invention;

Fig. 11 is the field curvature and distortion curves of the large aperture low-sensitivity optical lens assembly of Embodiment 4 of the present invention;

FIG. 12 is a spherical aberration curve of a large aperture low-sensitivity optical lens assembly according to Embodiment 4 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Example 1:

Referring to Fig. 1, the optical lens assembly with large aperture and low sensitivity of the present invention is composed of four plastic (resin) aspheric lenses, including the first lens 1, the second lens arranged in sequence from the object side to the imaging side. The lens 2 , the third lens 3 , the fourth lens 4 , the filter 5 , and the aperture 6 , wherein the aperture 6 is arranged on the object side of the first lens 1 , and the aperture is in front. The first lens 1 has positive refractive power, and the image side is convex; the second lens 2 has negative refractive power, and the object side is concave; the third lens 3 has an aspheric surface and has positive refractive power; the fourth lens 4 has an object side It is a concave surface, and both the object side and the image side are aspherical.

Wherein, the lens assembly, the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 satisfy the following relational expressions: 0.3<F1/TTL<1.0; 0.7<F/TTL<1.3; D3/D2< 3; -1<R7/F<-10; -1<R2/R1<-3; 4<(Vd1+Vd3)/Vd2<6; Vd1>50, Vd2<30; 0.1<n2-n1<0.25.

Wherein, F is the focal length of the lens assembly; F1 is the focal length of the first lens 1; D2 is the thickness of the second lens 2 on the optical axis; D3 is the thickness of the third lens 3 on the optical axis; R1 is the first lens 1 The radius of curvature of the object side surface; R2 is the curvature radius of the image side surface of the first lens 1; R7 is the curvature radius of the fourth lens 4 object side surface; TTL is the total length of the lens assembly; Vd1 is the A of the first lens 1 Vd2 is the Abbe number of the second lens 2; Vd3 is the Abbe number of the third lens 3; n1, n2 are the refractive indices of the first lens 1 and the second lens 2 respectively.

Wherein, in this embodiment, the central thickness of the first lens 1 is 0.785-0.815mm, the central thickness of the second lens 2 is 0.460-0.486mm, the central thickness of the third lens 3 is 0.695-0.713mm; the fourth lens 4 The center thickness is 0.586-0.615mm.

In addition, the aspheric surfaces of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 satisfy the formula:

$z=\frac{{\mathrm{cr}}^2}{1+\sqrt{1-(1+k)c^2{r}^2}}+{\mathrm{\&alpha;}}_1{r}^2+{\mathrm{\&alpha;}}_2{r}^4+{\mathrm{\&alpha;}}_3{r}^6+{\mathrm{\&alpha;}}_4{r}^8+{\mathrm{\&alpha;}}_5{r}^{10}+{\mathrm{\&alpha;}}_6{r}^{12}+{\mathrm{\&alpha;}}_7{r}^{14}+{\mathrm{\&alpha;}}_8{r}^{16},$ Among them, z represents the z coordinate value of each point on the lens surface, r represents the Y-axis coordinate value of each point on the lens surface, c is the reciprocal of the curvature radius R of the lens surface, k is the cone coefficient, α ₁ , α ₂ , α ₃ , α ₄ , α ₅ , α ₆ , α ₇ , α ₈ are aspheric coefficients.

The lens assembly can be further set according to the specific data of each parameter in the above formula, the data is shown in Table 1 (F=3.21mm, FNO=2.2, FOV=75.7°)

Table 1 Data sheet of each lens of the lens assembly

According to the above parameters, please refer to Figure 2 for the field curvature and distortion curve of the lens assembly; please refer to Figure 3 for the spherical aberration curve. It can be seen from FIG. 2 that the optical distortion of the lens assembly is less than 1%, the field curvature is less than 0.05mm, and the distortion of the imaging picture is small and the definition is high.

Example 2:

Referring to Fig. 4, the difference from Embodiment 1 is that in the large-aperture low-sensitivity optical lens assembly, the lens assembly, the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 satisfy the following relationship Mode:

0.3<F1/TTL<1.0; 0.7<F/TTL<1.3; D3/D2<3; -1<R7/F<-10; -1<R2/R1<-3; 1.5<(R4-R3)/ (R4+R3)<6.5; 4<(Vd1+Vd3)/Vd2<6; Vd1>50, Vd2<30; 0.1<n2-n1<0.25.

Wherein, F is the focal length of the lens assembly; F1 is the focal length of the first lens 1; D2 is the thickness of the second lens 2 on the optical axis; D3 is the thickness of the third lens 3 on the optical axis; R1 is the first lens 1 The radius of curvature of the surface on the object side; R2 is the radius of curvature of the surface of the image side of the first lens 1; R3 is the radius of curvature of the surface of the second lens 2 on the object side; R4 is the radius of curvature of the surface of the second lens 2 on the image side; R7 is the radius of curvature of the surface of the second lens 2 on the image side; The radius of curvature of the four-lens 4 object side surface; TTL is the total length of the lens assembly; Vd1 is the Abbe number of the first lens 1; Vd2 is the Abbe number of the second lens 2; Vd3 is the Abbe number of the third lens 3 n1, n2 are the refractive indices of the first lens 1 and the second lens 2, respectively.

Wherein, in this embodiment, the central thickness of the first lens 1 is 0.790-0.815mm, the central thickness of the second lens 2 is 0.605-0.628mm, the central thickness of the third lens 3 is 0.655-0.683mm; the fourth lens 4 The center thickness is 0.486-0.503mm.

The aspherical surfaces of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 satisfy the formula:

$z=\frac{{\mathrm{cr}}^2}{1+\sqrt{1-(1+k)c^2{r}^2}}+{\mathrm{\&alpha;}}_1{r}^2+{\mathrm{\&alpha;}}_2{r}^4+{\mathrm{\&alpha;}}_3{r}^6+{\mathrm{\&alpha;}}_4{r}^8+{\mathrm{\&alpha;}}_5{r}^{10}+{\mathrm{\&alpha;}}_6{r}^{12}+{\mathrm{\&alpha;}}_7{r}^{14}+{\mathrm{\&alpha;}}_8{r}^{16},$ Among them, z represents the z coordinate value of each point on the lens surface, r represents the Y-axis coordinate value of each point on the lens surface, c is the reciprocal of the curvature radius R of the lens surface, k is the cone coefficient, α ₁ , α ₂ , α ₃ , α ₄ , α ₅ , α ₆ , α ₇ , α ₈ are aspheric coefficients.

The lens assembly can be further set according to the specific data of each parameter in the above formula, the data is shown in Table 2 (F=3.19mm, FNO=2.2, FOV=75.3°)

Table 2 Data sheet of each lens of the lens assembly

According to the above parameters, the field curvature and distortion curve of the lens assembly, refer to Figure 5; refer to Figure 6 for the spherical aberration curve. It can be seen from FIG. 5 that the optical distortion of the lens assembly is less than 1.5%, the field curvature is less than 0.05mm, and the distortion of the imaging picture is small and the definition is high.

Example 3:

Referring to Fig. 7, the difference from Embodiment 2 is that in the aspheric formula of the large-aperture low-sensitivity optical lens assembly, the specific data of each parameter is shown in Table 3 (F=3.21mm, FNO=2.2, FOV=75.2° )

Table 3 Data sheet of each lens of the lens assembly

According to the above parameters, the field curvature and distortion curve of the lens assembly can be seen in FIG. 8 ; the spherical aberration curve can be seen in FIG. 9 . It can be seen from FIG. 8 that the optical distortion of the lens assembly is less than 1.5%, the field curvature is less than 0.1mm, and the distortion of the imaging picture is small and the definition is high.

Example 4:

Referring to FIG. 10 , the difference from Embodiment 1 is that the large-aperture low-sensitivity optical lens assembly includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens arranged in sequence from the object side to the imaging side. The lens 4, the filter 5, and the diaphragm 6, wherein the diaphragm 6 is arranged between the first lens 1 and the second lens 2, and adopts a structure in which the diaphragm is placed in the middle. The first lens 1 has positive refractive power, and the image side is convex; the second lens 2 has negative refractive power, and the object side is concave; the third lens 3 has an aspheric surface and has positive refractive power; the fourth lens 4 has an object side It is a concave surface, and both the object side and the image side are aspherical.

Wherein, the lens assembly, the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 satisfy the following relational expressions: 0.3<F1/TTL<1.0; 0.7<F/TTL<1.3; D3/D2< 3; 0.5<(R2-R1)/(R2+R1)<4.5; 4<(Vd1+Vd3)/Vd2<6; Vd1>50, Vd2<30; 0.1<n2-n1<0.25. Wherein, F is the focal length of the lens assembly; F1 is the focal length of the first lens 1; D2 is the thickness of the second lens 2 on the optical axis; D3 is the thickness of the third lens 3 on the optical axis; R1 is the first lens 1 The radius of curvature of the surface on the object side; R2 is the radius of curvature of the image-side surface of the first lens 1; TTL is the total length of the lens assembly; Vd1 is the Abbe number of the first lens 1; Vd2 is the Abbe number of the second lens 2 Vd3 is the Abbe number of the third lens 3; n1, n2 are the refractive indices of the first lens 1 and the second lens 2, respectively.

In this embodiment, the central thickness of the first lens 1 is 0.521-0.548 mm, the central thickness of the second lens 2 is 0.386-0.412 mm, the central thickness of the third lens 3 is 0.738-0.769 mm; the central thickness of the fourth lens 4 It is 0.602 ~ 0.643mm.

The aspherical surfaces of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 satisfy the formula:

$z=\frac{{\mathrm{cr}}^2}{1+\sqrt{1-(1+k)c^2{r}^2}}+{\mathrm{\&alpha;}}_1{r}^2+{\mathrm{\&alpha;}}_2{r}^4+{\mathrm{\&alpha;}}_3{r}^6+{\mathrm{\&alpha;}}_4{r}^8+{\mathrm{\&alpha;}}_5{r}^{10}+{\mathrm{\&alpha;}}_6{r}^{12}+{\mathrm{\&alpha;}}_7{r}^{14}+{\mathrm{\&alpha;}}_8{r}^{16},$ z represents the z coordinate value of each point on the lens surface, r represents the Y-axis coordinate value of each point on the lens surface, c represents the reciprocal of the curvature radius R of the lens surface, k represents the cone coefficient, α ₁ , α ₂ , α ₃ , α ₄ , α ₅ , α ₆ , α ₇ , α ₈ are aspheric coefficients.

The lens assembly can be further set according to the specific data of each parameter in the above formula, the data is shown in Table 4 (F=3.22mm, FNO=2.2, FOV=75.5°)

Table 4 Data sheet of each lens of the lens assembly

Refer to FIG. 11 for the field curvature and distortion curves of the lens assembly according to the above parameters; refer to FIG. 12 for the spherical aberration curve. It can be seen from FIG. 11 that the optical distortion of the lens assembly is less than 1.5%, the field curvature is less than 0.1mm, and the image distortion is small and the definition is high.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (6)

1. A large aperture low-sensitivity optical lens assembly, comprising a first lens (1), a second lens (2), a third lens (3), and a fourth lens (4) arranged in sequence from the object side to the image side , a filter (5) and a diaphragm (6) arranged on the object side of the first lens (1), characterized in that: The first lens (1) has positive refractive power, and the image side is convex; the second lens (2) has negative refractive power, and the object side is concave; the third lens (3) has an aspheric surface and has positive refractive power; the object side of the fourth lens (4) is concave, and both the object side and the image side are aspherical; the lens assembly, the first lens (1), the second lens (2), the third The lens (3) and the fourth lens (4) satisfy the following relationship: 0.3<F1/TTL<1.0; 0.7<F/TTL<1.3; D3/D2<3; -1<R7/F <-10; -1<R2/R1<-3; Wherein, F is the focal length of the lens assembly; F1 is the focal length of the first lens (1); D2 is the thickness of the second lens (2) on the optical axis; D3 is the third lens (3) Thickness on the optical axis; R1 is the radius of curvature of the object-side surface of the first lens (1); R2 is the radius of curvature of the image-side surface of the first lens (1); R7 is the radius of curvature of the fourth lens (4) ) The radius of curvature of the object-side surface; TTL is the total length of the lens assembly. 2. The large-aperture low-sensitivity optical lens assembly according to claim 1, characterized in that: the second lens (2) satisfies the following relationship: 1.5<(R4-R3)/(R4+R3)<6.5 , wherein R3 is the radius of curvature of the object-side surface of the second lens (2); R4 is the radius of curvature of the image-side surface of the second lens (2). 3. A large aperture low-sensitivity optical lens assembly, comprising a first lens (1), a second lens (2), a third lens (3), and a fourth lens (4) arranged in sequence from the object side to the image side , a filter (5) and a diaphragm (6) arranged between the first lens (1) and the second lens (2), characterized in that: The first lens (1) has positive refractive power, and the image side is convex; the second lens (2) has negative refractive power, and the object side is concave; the third lens (3) has an aspheric surface and has positive refractive power; the object side of the fourth lens (4) is concave, and both the object side and the image side are aspherical; the lens assembly, the first lens (1), the second lens (2), the third The lens (3) and the fourth lens (4) satisfy the following relationship: 0.3<F1/TTL<1.0; 0.7<F/TTL<1.3; D3/D2<3; 0.5<(R2-R1)/(R2+R1 )<4.5; Wherein, F is the focal length of the lens assembly; F1 is the focal length of the first lens (1); D2 is the thickness of the second lens (2) on the optical axis; D3 is the third lens (3) Thickness on the optical axis; R1 is the radius of curvature of the object-side surface of the first lens (1); R2 is the radius of curvature of the image-side surface of the first lens (1); TTL is the total length of the lens assembly. 4. The large-aperture low-sensitivity optical lens assembly according to claim 1 or 3, characterized in that: the first lens (1), the second lens (2), and the third lens (3) satisfy the following relationship : 4<(Vd1+Vd3)/Vd2<6, where Vd1 is the Abbe number of the first lens (1); Vd2 is the Abbe number of the second lens (2); Vd3 is the Abbe number of the third lens (3) shell number. 5. The large-aperture low-sensitivity optical lens assembly according to claim 4, characterized in that: the first lens (1) and the second lens (2) satisfy the following relational formula: Vd1>50, Vd2<30; Where Vd1 is the Abbe number of the first lens (1); Vd2 is the Abbe number of the second lens (2). 6. The large-aperture low-sensitivity optical lens assembly according to claim 1 or 3, characterized in that: the first lens (1) and the second lens (2) satisfy the following relationship: 0.1<n2-n1< 0.25; where n1 and n2 are the refractive indices of the first lens (1) and the second lens (2) respectively.