TW201915539A - Lens assembly - Google Patents

Abstract

A lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens is with refractive power and includes a convex surface facing the object side and a concave surface facing the image side. The second lens is with negative refractive power and includes a concave surface facing the object side. The third lens is with positive refractive power and includes a convex surface facing the image side. The fourth lens is with positive refractive power and includes a convex surface facing the image side. The fifth lens is a biconcave lens with negative refractive power. The sixth lens is with positive refractive power and includes a convex surface facing the object side.

Description

Imaging lens (20)

The invention relates to an imaging lens.

The conventional six-lens imaging lens usually has a long lens length. With different application requirements, it also needs to have a large aperture and the ability to resist environmental temperature changes. Therefore, another type of imaging lens with a new architecture is needed to meet the demands of miniaturization, large aperture, and resistance to environmental temperature changes.

In view of this, the main purpose of the present invention is to provide an imaging lens which has a shorter overall lens length, a smaller aperture value, a higher resolution, and resistance to environmental temperature changes, but still has good optical performance.

The imaging lens of the present invention includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. The first lens has refractive power and includes a convex surface facing an object side and a concave surface facing an image side. The second lens has negative refractive power and includes a concave surface facing the object side. The third lens has positive refractive power and includes a convex surface facing the image side. The fourth lens has positive refractive power and includes a convex surface facing the image side. The fifth lens is a biconcave lens with negative refractive power. The sixth lens has positive refractive power and includes a convex surface facing the object side. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in sequence along the optical axis from the object side to the image side.

The refractive power of the first lens is positive, and the fourth lens may further include a convex surface facing the object side.

The refractive power of the first lens is negative, and the fourth lens may further include a concave surface facing the object side.

The imaging lens satisfies the following conditions: 0.3<f ₃ /f<2.5;0.3<f ₄ /f<3.0; where f ₃ is the effective focal length of one of the third lenses, f ₄ is the effective focal length of one of the fourth lenses, f It is one of the effective focal lengths of the imaging lens.

The imaging lens satisfies the following conditions: 2.1<|f ₁ /f|<4.0;-1.8<f ₅ /f<-0.2; where f ₁ is the effective focal length of one of the first lenses and f ₅ is one of the fifth lenses Effective focal length, f is one of the effective focal lengths of the imaging lens.

The imaging lens satisfies the following conditions: 0.1<|BFL/TTL|<0.5; where, BFL is a distance from the image side of the sixth lens to an imaging plane on the optical axis, and TTL is the object side of the first lens to The imaging plane is spaced on the optical axis.

The second lens may further include a concave surface facing the image side, the third lens may further include a convex surface facing the object side, and the sixth lens may further include a convex surface facing the image side.

The fourth lens is cemented with the fifth lens.

The imaging lens of the present invention may further include an aperture disposed between the second lens and the fourth lens.

The first lens, the second lens, the third lens, the fourth lens, and the fifth lens are spherical glass lenses, and the sixth lens is an aspheric glass lens.

In order to make the above objects, features, and advantages of the present invention more comprehensible, preferred embodiments are described in detail below in conjunction with the accompanying drawings.

1, 2, 3‧‧‧ imaging lens

L11, L21, L31 ‧‧‧ first lens

L12, L22, L32 ‧‧‧ second lens

L13, L23, L33 ‧‧‧ third lens

L14, L24, L34 ‧‧‧ fourth lens

L15, L25, L35 ‧‧‧ fifth lens

L16, L26, L36 ‧‧‧ sixth lens

ST1, ST2, ST3 ‧‧‧ aperture

OF1, OF2, OF3 ‧‧‧ filter

CG1, CG2, CG3‧‧‧protective glass

OA1, OA2, OA3 ‧‧‧ optical axis

IMA1, IMA2, IMA3 ‧‧‧ imaging surface

S11, S12, S13, S14, S15, S16

S17, S18, S19, S110, S111

S112, S113, S114, S115, S116

S21, S22, S23, S24, S25, S26

S27, S28, S29, S210, S211

S212, S213, S214, S215, S216

S31, S32, S33, S34, S35, S36, S37

S38, S39, S310, S311, S312

S313, S314, S315, S316, S317

FIG. 1 is a schematic diagram of a lens configuration according to the first embodiment of the imaging lens of the present invention.

FIG. 2A is a longitudinal aberration (Longitudinal Aberration) diagram of the first embodiment of the imaging lens according to the present invention.

FIG. 2B is a field curvature diagram of the first embodiment of the imaging lens according to the present invention.

FIG. 2C is a distortion diagram of the first embodiment of the imaging lens according to the present invention.

FIG. 2D is a Lateral Color diagram of the first embodiment of the imaging lens of the present invention.

FIG. 2E is a diagram of the relative illumination of the first embodiment of the imaging lens according to the present invention.

FIG. 2F is a modulation transfer function diagram of the first embodiment of the imaging lens of the present invention.

FIG. 2G is a diagram of the Through Focus Modulation Transfer Function of the first embodiment of the imaging lens of the present invention.

FIG. 3 is a schematic diagram of a lens configuration according to a second embodiment of the imaging lens of the present invention.

FIG. 4A is a longitudinal aberration (Longitudinal Aberration) diagram of the second embodiment of the imaging lens according to the present invention.

FIG. 4B is a field curvature diagram of a second embodiment of the imaging lens according to the present invention.

FIG. 4C is a distortion diagram of the second embodiment of the imaging lens according to the present invention.

FIG. 4D is a Lateral Color diagram of the second embodiment of the imaging lens of the present invention.

FIG. 4E is a relative illumination diagram of the second embodiment of the imaging lens according to the present invention.

FIG. 4F is a modulation transfer function diagram of the second embodiment of the imaging lens of the present invention.

FIG. 4G is a diagram of a Through Focus Modulation Transfer Function according to the second embodiment of the imaging lens of the present invention.

FIG. 5 is a schematic diagram of a lens configuration of a third embodiment of the imaging lens according to the present invention.

FIG. 6A is a longitudinal aberration (Longitudinal Aberration) diagram of the third embodiment of the imaging lens according to the present invention.

FIG. 6B is a field curvature diagram of the third embodiment of the imaging lens according to the present invention.

FIG. 6C is a distortion diagram of the third embodiment of the imaging lens according to the present invention.

FIG. 6D is a Lateral Color diagram of the third embodiment of the imaging lens according to the present invention.

FIG. 6E is a diagram of the relative illumination of the third embodiment of the imaging lens according to the present invention.

FIG. 6F is a modulation transfer function diagram of the third embodiment of the imaging lens according to the present invention.

FIG. 6G is a diagram of a Through Focus Modulation Transfer Function according to the third embodiment of the imaging lens of the present invention.

Please refer to FIG. 1, which is a schematic diagram of a lens configuration according to the first embodiment of the imaging lens of the present invention. The imaging lens 1 includes a first lens L11, a second lens L12, an aperture ST1, a third lens L13, a fourth lens L14, a first lens in order from an object side to an image side along an optical axis OA1 Five lenses L15, a sixth lens L16, a filter OF1 and a protective glass CG1. When imaging, the light from the object side is finally imaged on an imaging surface IMA1.

The first lens L11 is a meniscus lens with a positive refractive power made of glass material, its object side S11 is convex, the image side S12 is concave, and both the object side S11 and the image side S12 are spherical surfaces.

The second lens L12 is a biconcave lens made of glass material with negative refractive power, its object side S13 is concave, the image side S14 is concave, and both the object side S13 and the image side S14 are spherical surfaces.

The third lens L13 is a biconvex lens with positive refractive power made of glass material, its object side S16 is convex, the image side S17 is convex, and both the object side S16 and the image side S17 are spherical surfaces.

The fourth lens L14 is a biconvex lens with positive refractive power made of glass material, its object side S18 is convex, the image side S19 is convex, and both the object side S18 and the image side S19 are spherical surfaces.

The fifth lens L15 is a biconcave lens with a negative refractive power made of glass material. Its object side S19 is concave, the image side S110 is concave, and both the object side S19 and the image side S110 are spherical surfaces.

The sixth lens L16 is a biconvex lens with positive refractive power made of glass material. The object side S111 is convex, the image side S112 is convex, and both the object side S111 and the image side S112 are aspherical surfaces.

The fourth lens L14 and the fifth lens L15 are cemented with each other.

The object side S113 and the image side S114 of the filter OF1 are both flat.

The object side S115 and the image side S116 of the protective glass CG1 are both flat.

In addition, the imaging lens 1 in the first embodiment satisfies at least one of the following conditions: 2.1<|f1 ₁ /f1|<4.0 (1)

0.3<f1 ₃ /f1<2.5 (2)

0.3<f1 ₄ /f1<3.0 (3)

-1.8<f1 ₅ /f1<-0.2 (4)

0.1<|BFL1/TTL1|<0.5 (5)

Where f1 is one of the effective focal lengths of the imaging lens 1, f1 ₁ is one of the effective focal lengths of the first lens L11, f1 ₃ is one of the effective focal lengths of the third lens L13, and f1 ₄ is one of the effective focal lengths of the fourth lens L14, f1 ₅ It is one of the effective focal lengths of the fifth lens L15, BFL1 is the distance between the image side S112 of the sixth lens L16 to the imaging plane IMA1 on the optical axis OA1, and TTL1 is the object side S11 of the first lens L11 to the imaging plane IMA1 at the optical axis One pitch on OA1.

The use of the above lens and aperture and the design that satisfies at least one of the conditions (1) to (5) enables the imaging lens 1 to effectively shorten the total lens length, effectively reduce the aperture value, improve resolution, and effectively correct aberrations 3. Resistant to environmental temperature changes.

If the absolute value of the condition (1) f1 ₁ /f1 is less than 2.1, the manufacturability of the lens is poor. Therefore, the absolute value of f1 ₁ /f1 must be at least greater than 2.1, so the best effect range is 2.1<|f1 ₁ /f1|<4.0, and within this range, a better balance between wide-angle optical characteristics and lens manufacturability Among them, if the absolute value of f1 ₁ /f1 becomes larger, better lens manufacturability can be obtained, and if the absolute value of f1 ₁ /f1 becomes smaller, higher peripheral resolution performance can be obtained.

Table 1 is a table of related parameters of each lens of the imaging lens 1 in FIG. 1. The data in Table 1 shows that the effective focal length of the imaging lens 1 of the first embodiment is 9.600 mm, the aperture value is 1.6, and the total lens length is 20.99 mm. The half field of view is equal to 28.4 degrees.

The aspherical surface concave degree z of each lens in Table 1 is obtained by the following formula: z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹²

Among them: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~E: aspherical coefficient.

Table 2 is the related parameter table of the aspherical surface of each lens in Table 1, where k is the conic constant and A~E are the aspherical coefficients.

Table 3 is the parameter values in Condition (1) to Condition (5) and the calculated values of Condition (1) to Condition (5). As can be seen from Table 3, the imaging lens 1 of the first embodiment can satisfy the condition (1) To the requirements of condition (5).

In addition, the optical performance of the imaging lens 1 of the first embodiment can also meet the requirements, which can be seen from FIGS. 2A to 2G. Shown in FIG. 2A is a longitudinal aberration (Longitudinal Aberration) diagram of the imaging lens 1 of the first embodiment. Shown in FIG. 2B is a field curvature diagram of the imaging lens 1 of the first embodiment. Shown in FIG. 2C is a distortion diagram of the imaging lens 1 of the first embodiment. Shown in FIG. 2D is a lateral chromatic aberration (Lateral Color) diagram of the imaging lens 1 of the first embodiment. Shown in FIG. 2E is a relative illumination (Relative Illumination) diagram of the imaging lens 1 of the first embodiment. Shown in FIG. 2F is a modulation transfer function (Modulation Transfer Function) diagram of the imaging lens 1 of the first embodiment. Shown in FIG. 2G is a diagram of the Through Focus Modulation Transfer Function of the imaging lens 1 of the first embodiment.

As can be seen from FIG. 2A, the imaging lens 1 of the first embodiment has a longitudinal aberration value between -0.025 mm and 0.035 mm for light rays with wavelengths of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, and 0.650 μm. between.

As can be seen from FIG. 2B, the imaging lens 1 of the first embodiment has a wavelength of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, and 0.650 μm in the meridional (Tangential) direction and sagittal (Sagittal) direction. The curvature of field is between -0.03mm and 0.035mm.

It can be seen from Figure 2C (the five lines in the figure almost overlap, so that there seems to be only one line), the imaging lens 1 of the first embodiment has a pair of wavelengths of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, 0.650 The distortion produced by μm light is between -2% and 0%.

As can be seen from the 2D image, the imaging lens 1 of the first embodiment produces a horizontal color at a maximum field of view equal to 3.000 mm for light with wavelengths of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, and 0.650 μm. The difference is between -0.5μm and 2.0μm.

It can be seen from FIG. 2E that the imaging lens 1 of the first embodiment has a relative illuminance between 0.82 and 1.0 for the light with a wavelength of 0.555 μm in the Y field of view between 0 mm and 3 mm.

As can be seen from FIG. 2F, the imaging lens 1 of the first embodiment, for the light with a wavelength range of 0.4700 μm to 0.6500 μm, respectively in the meridian (Tangential) direction and sagittal (Sagittal) direction, the field of view height is respectively 0.0000mm, 0.3000mm, 0.6000mm, 1.2000mm, 1.5000mm, 2.1000mm, 2.4000mm, 2.7000mm, 3.000mm, the spatial frequency is from 0lp/mm to 60lp/mm, and its modulation transfer function value is from 0.35 to 1.0 between.

As can be seen from FIG. 2G, the imaging lens 1 of the first embodiment, for light with a wavelength range of 0.4700 μm to 0.6500 μm, respectively in the meridian (Tangential) direction and sagittal (Sagittal) direction, the field of view height is respectively 0.0000mm, 0.3000mm, 0.6000mm, 1.2000mm, 1.5000mm, 2.1000mm, 2.4000mm, 2.7000mm, 3.000mm, when the spatial frequency is equal to 60lp/mm, when the focus shift is between -0.025mm and 0.021mm The modulation transfer function values are all greater than 0.2.

It is obvious that the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 1 of the first embodiment can be effectively corrected, and the relative illuminance, lens resolution, and depth of focus can also meet the requirements, thereby obtaining better optical performance.

Please refer to FIG. 3, which is a schematic diagram of a lens configuration according to a second embodiment of the imaging lens of the present invention. The imaging lens 2 includes a first lens L21, a second lens L22, an aperture ST2, a third lens L23, a fourth lens L24, a first lens in order from an object side to an image side along an optical axis OA2 Five lenses L25, a sixth lens L26, a filter OF2 and a protective glass CG2. When imaging, the light from the object side is finally imaged on an imaging surface IMA2.

The first lens L21 is a meniscus lens with a positive refractive power made of glass material, its object side S21 is convex, the image side S22 is concave, and both the object side S21 and the image side S22 are spherical surfaces.

The second lens L22 is a biconcave lens made of glass material with negative refractive power, its object side S23 is concave, the image side S24 is concave, and both the object side S23 and the image side S24 are spherical surfaces.

The third lens L23 is a biconvex lens with positive refractive power made of glass material, its object side S26 is convex, the image side S27 is convex, and both the object side S26 and the image side S27 are spherical surfaces.

The fourth lens L24 is a biconvex lens with positive refractive power made of glass material, its object side S28 is convex, the image side S29 is convex, and both the object side S28 and the image side S29 are spherical surfaces.

The fifth lens L25 is a biconcave lens made of glass material with negative refractive power. The object side S29 is concave, the image side S210 is concave, and both the object side S29 and the image side S210 are spherical surfaces.

The sixth lens L26 is a biconvex lens with positive refractive power made of glass material. The object side S211 is convex, the image side S212 is convex, and both the object side S211 and the image side S212 are aspherical surfaces.

The fourth lens L24 and the fifth lens L25 are cemented with each other.

The object side S213 and the image side S214 of the filter OF2 are both flat.

The object side S215 and the image side S216 of the protective glass CG2 are both flat.

In addition, the imaging lens 2 in the second embodiment satisfies at least one of the following conditions: 2.1<|f2 ₁ /f2|<4.0 (6)

0.3<f2 ₃ /f2<2.5 (7)

0.3<f2 ₄ /f2<3.0 (8)

-1.8<f2 ₅ /f2<-0.2 (9)

0.1<|BFL2/TTL2|<0.5 (10)

The definitions of f2, f2 ₁ , f2 ₃ , f2 ₄ , f2 ₅ , BFL2 and TTL2 are the same as the definitions of f1, f1 ₁ , f1 ₃ , f1 ₄ , f1 ₅ , BFL1 and TTL1 in the first embodiment. Not to repeat them.

Using the above lens, aperture and at least one design that satisfies one of the conditions (6) to (10), the imaging lens 2 can effectively shorten the total lens length, effectively reduce the aperture value, improve resolution, and effectively correct aberrations 3. Resistant to environmental temperature changes.

If the value of the condition (7) f2 ₃ /f2 is less than 0.3, the manufacturability of the lens is poor. Therefore, the value of f2 ₃ /f2 must be at least greater than 0.3, so the best effect range is 0.3<f2 ₃ /f2<2.5, and within this range, a good balance between wide-angle optical characteristics and lens manufacturability can be achieved. If the value of f2 ₃ /f2 becomes larger, better lens manufacturability can be obtained, and if the value of f2 ₃ /f2 becomes smaller, higher peripheral resolution performance can be obtained.

Table 4 is a table of related parameters of each lens of the imaging lens 2 in FIG. 3. The data in Table 4 shows that the effective focal length of the imaging lens 2 of the second embodiment is 9.600 mm, the aperture value is 1.6, and the total lens length is 20.5 mm. The half field of view is equal to 28.4 degrees.

The aspherical surface depression degree z of each lens in Table 4 is obtained by the following formula: z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹²

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~E: aspherical coefficient.

Table 5 is the related parameter table of the aspherical surface of each lens in Table 4, where k is the conic constant and A~E are the aspherical coefficients.

Table 6 is the parameter values in Condition (6) to Condition (10) and the calculated values of Condition (6) to Condition (10). From Table 6, it can be seen that the imaging lens 2 of the second embodiment can satisfy the condition (6) To the requirements of condition (10).

In addition, the optical performance of the imaging lens 2 of the second embodiment can also meet the requirements, which can be seen from FIGS. 4A to 4G. FIG. 4A is a longitudinal aberration (Longitudinal Aberration) diagram of the imaging lens 2 of the second embodiment. Shown in FIG. 4B is a field curvature diagram of the imaging lens 2 of the second embodiment. Shown in FIG. 4C is a distortion diagram of the imaging lens 2 of the second embodiment. FIG. 4D is a lateral chromatic aberration (Lateral Color) diagram of the imaging lens 2 of the second embodiment. Shown in FIG. 4E is a relative illumination (Relative Illumination) diagram of the imaging lens 2 of the second embodiment. Shown in FIG. 4F is a modulation transfer function (Modulation Transfer Function) diagram of the imaging lens 2 of the second embodiment. Shown in FIG. 4G is a diagram of a Through Focus Modulation Transfer Function of the imaging lens 2 of the second embodiment.

As can be seen from FIG. 4A, the imaging lens 2 of the second embodiment has a longitudinal aberration value between 0 mm and 0.04 mm for light rays with wavelengths of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, and 0.650 μm. .

As can be seen from FIG. 4B, the imaging lens 2 of the second embodiment has a wavelength of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, and 0.650 μm in the direction of the meridian (Tangential) and sagittal (Sagittal). The field curvature is between -0.015mm and 0.045mm.

It can be seen from Figure 4C (the five lines in the figure almost coincide so that there is only one line), the imaging lens 2 of the second embodiment has a pair of wavelengths of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, 0.650 The distortion produced by μm light is between -1.9% and 0%.

It can be seen from FIG. 4D that the imaging lens 2 of the second embodiment produces a lateral color at a maximum field of view height equal to 3.000 mm for light with wavelengths of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, and 0.650 μm. The difference is between 0 μm and 1.5 μm.

As can be seen from FIG. 4E, the imaging lens 2 of the second embodiment has a relative illuminance of 0.85 to 1.0 for the light with a wavelength of 0.555 μm in the Y field of view of 0 mm to 3 mm.

As can be seen from FIG. 4F, the imaging lens 2 of the second embodiment, for light with a wavelength range of 0.4700 μm to 0.6500 μm, respectively in the meridian (Tangential) direction and sagittal (Sagittal) direction, the field of view height is respectively 0.0000mm, 0.3000mm, 0.6000mm, 1.2000mm, 1.5000mm, 2.1000mm, 2.4000mm, 2.7000mm, 3.000mm, the spatial frequency is between 0lp/mm and 60lp/mm, and its modulation transfer function value is between 0.31 and 1.0 between.

As can be seen from FIG. 4G, the imaging lens 2 of the second embodiment, for light with a wavelength range of 0.4700 μm to 0.6500 μm, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, the field of view height is respectively 0.0000mm, 0.3000mm, 0.6000mm, 1.2000mm, 1.5000mm, 2.1000mm, 2.4000mm, 2.7000mm, 3.000mm, when the spatial frequency is equal to 60lp/mm, when the focus shift is between -0.016mm and 0.023mm The modulation transfer function values are all greater than 0.2.

It is obvious that the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 2 of the second embodiment can be effectively corrected, and the relative illuminance, lens resolution, and focal depth can also meet the requirements, thereby obtaining better optical performance.

Please refer to FIG. 5, which is a schematic diagram of a lens configuration according to a third embodiment of the imaging lens of the present invention. The imaging lens 3 includes a first lens L31, a second lens L32, a third lens L33, an aperture ST3, a fourth lens L34, a first lens in order from an object side to an image side along an optical axis OA3 Five lenses L35, a sixth lens L36, a filter OF3 and a protective glass CG3. When imaging, the light from the object side is finally imaged on an imaging surface IMA3.

The first lens L31 is a meniscus lens with negative refractive power and is made of glass material. Its object side S31 is convex, the image side S32 is concave, and both the object side S31 and the image side S32 are spherical surfaces.

The second lens L32 is a biconcave lens made of plastic material with negative refractive power. The object side S33 is concave, the image side S34 is concave, and both the object side S33 and the image side S34 are aspherical surfaces.

The third lens L33 is a biconvex lens with positive refractive power made of glass material, its object side S35 is convex, the image side S36 is convex, and both the object side S35 and the image side S36 are spherical surfaces.

The fourth lens L34 is a meniscus lens with positive refractive power made of plastic material. Its object side S38 is concave, the image side S39 is convex, and both the object side S38 and the image side S39 are aspherical surfaces.

The fifth lens L35 is a biconcave lens made of plastic material with negative refractive power. Its object side S310 is concave, the image side S311 is concave, and both the object side S310 and the image side S311 are aspherical surfaces.

The sixth lens L36 is a biconvex lens with positive refractive power made of plastic material. Its object side S312 is convex, the image side S313 is convex, and both the object side S312 and the image side S313 are aspherical surfaces.

The object side S314 and the image side S315 of the filter OF3 are both flat.

The object side S316 and the image side S317 of the protective glass CG3 are flat.

In addition, the imaging lens 3 in the third embodiment satisfies at least one of the following conditions: 2.1<|f3 ₁ /f3|<4.0 (11)

0.3<f3 ₃ /f3<2.5 (12)

0.3<f3 ₄ /f3<3.0 (13)

-1.8<f3 ₅ /f3<-0.2 (14)

0.1<|BFL3/TTL3|<0.5 (15)

The definitions of f3, f3 ₁ , f3 ₃ , f3 ₄ , f3 ₅ , BFL3 and TTL3 are the same as the definitions of f1, f1 ₁ , f1 ₃ , f1 ₄ , f1 ₅ , BFL1 and TTL1 in the first embodiment. Not to repeat them.

The use of the above lens, aperture and design that satisfies at least one of the conditions (11) to (15) enables the imaging lens 3 to effectively shorten the total lens length, effectively reduce the aperture value, improve resolution, and effectively correct aberrations 3. Resistant to environmental temperature changes.

If the value of the condition (13) f3 ₄ /f3 is less than 0.3, the manufacturability of the lens is poor. Therefore, the value of f3 ₄ /f3 must be at least greater than 0.3, so the best effect range is 0.3<f3 ₄ /f3<3.0, and within this range, a better balance between wide-angle optical characteristics and lens manufacturability can be achieved. If the value of f3 ₄ /f3 becomes larger, better lens manufacturability can be obtained, and if the value of f3 ₄ /f3 becomes smaller, higher peripheral resolution performance can be obtained.

Table 7 is a table of related parameters of each lens of the imaging lens 3 in FIG. 5. The data in Table 7 shows that the effective focal length of the imaging lens 3 of the third embodiment is 1.333 mm, the aperture value is 2.0, and the total lens length is 13.501 mm. The half field of view is equal to 180 degrees.

The aspherical surface depression degree z of each lens in Table 7 is obtained by the following formula: z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹² +Fh ¹⁴

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~F: aspherical coefficient.

Table 8 is the related parameter table of the aspherical surface of each lens in Table 7, where k is the conic constant and A~F are the aspherical coefficients.

Table 9 shows the parameter values in Condition (11) to Condition (15) and the calculated values of Condition (11) to Condition (15). As can be seen from Table 9, the imaging lens 3 of the third embodiment can satisfy the condition (11) To the requirements of condition (15).

In addition, the optical performance of the imaging lens 3 of the third embodiment can also meet the requirements, which can be seen from FIGS. 6A to 6G. FIG. 6A shows a longitudinal aberration (Longitudinal Aberration) diagram of the imaging lens 3 of the third embodiment. FIG. 6B shows a field curvature diagram of the imaging lens 3 of the third embodiment. Shown in FIG. 6C is a distortion diagram of the imaging lens 3 of the third embodiment. FIG. 6D is a lateral chromatic aberration (Lateral Color) diagram of the imaging lens 3 of the third embodiment. Shown in FIG. 6E is a relative illuminance (Relative Illumination) diagram of the imaging lens 3 of the third embodiment. Shown in FIG. 6F is a modulation transfer function (Modulation Transfer Function) diagram of the imaging lens 3 of the third embodiment. Shown in FIG. 6G is a diagram of the Through Focus Modulation Transfer Function of the imaging lens 3 of the third embodiment.

As can be seen from FIG. 6A, the imaging lens 3 of the third embodiment has a longitudinal aberration value between -0.015mm and 0.03mm for light with wavelengths of 0.470μm, 0.510μm, 0.555μm, 0.610μm, and 0.650μm. between.

It can be seen from FIG. 6B that the imaging lens 3 of the third embodiment has a wavelength of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, and 0.650 μm in the meridional (Tangential) direction and sagittal (Sagittal) direction. The field curvature is between -0.02mm and 0.03mm.

It can be seen from Fig. 6C (the five lines in the figure almost coincide so that there is only one line), the imaging lens 3 of the third embodiment has a pair of wavelengths of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, 0.650 The distortion produced by μm light is between -100% and 0%.

It can be seen from Figure 6D that the imaging lens 3 of the third embodiment produces a lateral color at a maximum field angle equal to 90.0000 degrees for light with wavelengths of 0.470 μm, 0.510 μm, 0.555 μm, 0.610 μm, and 0.650 μm. The difference is between -1μm and 2.5μm.

It can be seen from FIG. 6E that the imaging lens 3 of the third embodiment has a relative illumination of 0.71 to 1.0 for the light with a wavelength of 0.555 μm in the Y field of view between 0 degrees and 90 degrees.

As can be seen from FIG. 6F, the imaging lens 3 of the third embodiment, for light with a wavelength range of 0.4700 μm to 0.6500 μm, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, the field of view angles are respectively 0.00 degrees, 9.00 degrees, 36.00 degrees, 54.00 degrees, 63.00 degrees, 72.00 degrees, 81.00 degrees, 90.00 degrees, the spatial frequency is between 0lp/mm and 60lp/mm, and its modulation conversion function value is between 0.65 and 1.0.

As can be seen from FIG. 6G, the imaging lens 3 of the third embodiment, for light with a wavelength range of 0.4700 μm to 0.6500 μm, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, the field of view angles are respectively 0.00 degrees, 9.00 degrees, 36.00 degrees, 54.00 degrees, 63.00 degrees, 72.00 degrees, 81.00 degrees, 90.00 degrees, when the spatial frequency is equal to 60lp/mm, when the focus shift is between -0.033mm and 0.034mm, its modulation conversion The function values are all greater than 0.2.

It is obvious that the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 3 of the third embodiment can be effectively corrected, and the relative illuminance, lens resolution, and depth of focus can also meet the requirements, thereby obtaining better optical performance.

The conditions met by the present invention are centered on 2.1<|f ₁ /f|<4.0, 0.3<f ₃ /f<2.5, 0.3<f ₄ /f<3.0, and the numerical values of the embodiments of the present invention also fall within the scope of the remaining conditions Inside. Conditions 2.1<|f ₁ /f|<4.0, 0.3<f ₃ /f<2.5, 0.3<f ₄ /f<3.0, which can help the balanced performance between wide-angle optical characteristics and lens manufacturability.

Although the present invention has been disclosed as above in an embodiment, it is not intended to limit the present invention. Anyone who is familiar with this art can make various changes and modifications within the spirit and scope of the present invention, so the protection of the present invention The scope shall be determined by the scope of the attached patent application.

Claims (10)

An imaging lens includes: a first lens having refractive power, the first lens including a convex surface facing an object side and a concave surface facing an image side; a second lens having negative refractive power, the second lens including a concave surface facing the object Side; a third lens has positive refractive power, the third lens includes a convex surface toward the image side; a fourth lens has positive refractive power, the fourth lens includes a convex surface toward the image side; a fifth lens has negative refractive power, The fifth lens is a biconcave lens; and a sixth lens has positive refractive power, the sixth lens includes a convex surface facing the object side; wherein the first lens, the second lens, the third lens, the fourth lens, The fifth lens and the sixth lens are sequentially arranged along the optical axis from the object side to the image side. The imaging lens as described in item 1 of the patent application range, wherein the refractive power of the first lens is positive, and the fourth lens further includes a convex surface facing the object side. The imaging lens as described in item 1 of the patent application, wherein the first lens has a negative refractive power, and the fourth lens further includes a concave surface facing the object side. The imaging lens as described in item 2 or item 3 of the patent application scope, wherein the imaging lens satisfies the following conditions: 0.3<f ₃ /f<2.5;0.3<f ₄ /f<3.0; where f _{3 is} the One of the three lenses has an effective focal length, f _{4 is} an effective focal length of the fourth lens, and f is an effective focal length of the imaging lens. The imaging lens as described in item 4 of the patent application scope, wherein the imaging lens satisfies the following conditions: 2.1<|f ₁ /f|<4.0;-1.8<f ₅ /f<-0.2; where f _{1 is} the first One effective focal length of one lens, f _{5 is} one effective focal length of the fifth lens, and f is one effective focal length of the imaging lens. The imaging lens as described in item 2 or item 3 of the patent application scope, wherein the imaging lens satisfies the following conditions: 0.1<|BFL/TTL|<0.5; wherein, BFL is one of the sixth lens image side to one imaging A distance between the surface and the optical axis, TTL is a distance from the object side of the first lens to the imaging surface on the optical axis. The imaging lens as described in item 2 or 3 of the patent application, wherein the second lens further includes a concave surface facing the image side, the third lens further includes a convex surface facing the object side, and the sixth lens further includes A convex surface faces the image side. The imaging lens described in item 2 or item 3 of the patent application scope further includes an aperture disposed between the second lens and the fourth lens. The imaging lens as described in item 1 of the patent application scope, wherein the fourth lens is cemented with the fifth lens. The imaging lens as described in item 1 of the patent application scope, wherein the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are spherical glass lenses, and the sixth lens is aspheric Glass lens.