TWI808344B - 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. The first lens is with negative refractive power and includes a concave surface facing an image side. The second lens is with positive refractive power and includes a convex surface facing an object side. The third lens is with positive refractive power. The fourth lens is with negative refractive power. The fifth lens is a meniscus lens with positive refractive power. The sixth lens is with positive refractive power and includes a concave surface facing the imaget side. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in order from the object side to the image side along an optical axis. An air gap is between the third lens and the fourth lens.

Description

Imaging lens(47)

The invention relates to an imaging lens.

The development trend of today's imaging lenses is that in addition to the continuous development towards large apertures, with the needs of different applications, it is also necessary to have the characteristics of high resolution and resistance to environmental temperature changes. The conventional imaging lenses can no longer meet the current needs. Another imaging lens with a new structure is needed to meet the needs of large apertures, high resolution and resistance to environmental temperature changes at the same time.

In view of this, the main purpose of the present invention is to provide an imaging lens with a small aperture value, high resolution, and resistance to environmental temperature changes, but still has good optical performance.

The invention provides an imaging lens including a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. The first lens has negative refractive power and includes a concave surface facing an image side. The second lens has positive refractive power and includes a convex surface facing an object side. The third lens has positive refractive power. The fourth lens has negative refractive power. The fifth lens is a meniscus lens with positive refractive power. The sixth lens has positive refractive power and includes a concave surface facing the image side. The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially arranged along an optical axis from the object side to the image side. An air space is included between the third lens and the fourth lens.

Wherein the first lens may further include another concave surface facing the object side, the second lens may further Including another convex surface facing the image side, the third lens is a biconvex lens and includes a convex surface facing the object side and another convex surface facing the image side, the fourth lens is a biconcave lens and includes a concave surface facing the object side and another concave surface facing the image side, the fifth lens includes a concave surface facing the object side and a convex surface facing the image side, and the sixth lens may further include a convex surface facing the object side.

Wherein the first lens may further include a convex surface facing the object side, the second lens may further include a concave surface facing the image side, the third lens is a biconvex lens and includes a convex surface facing the object side and another convex surface facing the image side, the fourth lens is a biconcave lens and includes a concave surface facing the object side and another concave surface facing the image side, the fifth lens includes a concave surface facing the object side and a convex surface facing the image side, and the sixth lens may further include a convex surface facing the object side.

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

Wherein the first lens, the second lens and the third lens include at least one glass spherical lens, and the fourth lens, the fifth lens and the sixth lens include at least one glass spherical lens.

The imaging lens satisfies the following condition: 120<Vd ₁ +Vd ₃ <140; wherein, Vd ₁ is an Abbe coefficient of one of the first lenses, and Vd ₃ is an Abbe coefficient of one of the third lenses.

The imaging lens satisfies the following condition: 0.4<(f ₃ +f ₄ )/f<0.62; wherein, f ₃ is an effective focal length of one of the third lenses, f ₄ is an effective focal length of one of the fourth lenses, and f is an effective focal length of one of the imaging lenses.

The imaging lens satisfies the following condition: -7<R ₂₂ /R ₂₁ <48; wherein, R ₂₁ is a radius of curvature of an object side of the second lens, and R ₂₂ is a radius of curvature of an image side of the second lens.

The imaging lens satisfies the following conditions: 6mm<f ₄ +f ₆ <12mm; wherein, f ₄ is an effective focal length of one of the fourth lenses, and f ₆ is an effective focal length of one of the sixth lenses.

Wherein the imaging lens satisfies the following condition: 3.9<TTL/BFL<6; wherein, TTL is the distance between the object side of the first lens and an imaging surface on the optical axis, and BFL is the distance between the image side of the sixth lens and the imaging surface on the optical axis.

The imaging lens satisfies the following conditions: 0.05<f ₁₂₃ /f ₄₅₆ <0.22; wherein, f ₁₂₃ is the combined effective focal length of one of the first lens, the second lens and the third lens, and f ₄₅₆ is the combined effective focal length of one of the fourth lens, the fifth lens and the sixth lens.

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

1, 2, 3, 4: imaging lens

L11, L21, L31, L41: first lens

L12, L22, L32, L42: second lens

L13, L23, L33, L43: third lens

L14, L24, L34, L44: fourth lens

L15, L25, L35, L45: fifth lens

L16, L26, L36, L46: sixth lens

ST1, ST2, ST3, ST4: Aperture

OA1, OA2, OA3, OA4: optical axis

OF1, OF2, OF3, OF4: Filters

CG1, CG2, CG3, CG4: Protective glass

IMA1, IMA2, IMA3, IMA4: imaging surface

S11, S21, S31, S41: the object side of the first lens

S12, S22, S32, S42: the side of the first lens image

S13, S23, S33, S43: second lens object side

S14, S24, S34, S44: the second lens image side

S15, S25, S35, S45: third lens object side

S16, S26, S36, S46: the third lens image side

S17, S27, S37, S47: aperture surface

S18, S28, S38, S48: the object side of the fourth lens

S19, S29, S39, S49: the side of the fourth lens image

S110, S210, S310, S410: fifth lens object side

S111, S211, S311, S411: the side image of the fifth lens

S112, S212, S312, S412: the object side of the sixth lens

S113, S213, S313, S413: the side image of the sixth lens

S114, S214, S314, S414: Filter object side

S115, S215, S315, S415: filter like the side

S116, S216, S316, S416: protect the side of the glass object

S117, S217, S317, S417: protective glass like the side

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

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

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

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

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

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

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

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

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

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

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

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

FIG. 7 is a schematic diagram of the lens configuration of the fourth embodiment of the imaging lens according to the present invention.

Fig. 8A is a longitudinal aberration (Longitudinal Aberration) diagram of the fourth embodiment of the imaging lens according to the present invention

FIG. 8B is a field curvature diagram of the fourth embodiment of the imaging lens according to the present invention.

FIG. 8C is a distortion diagram of the fourth embodiment of the imaging lens according to the present invention.

FIG. 8D is a lateral color aberration (Lateral Color) diagram of the fourth embodiment of the imaging lens according to the present invention.

FIG. 8E is a relative illumination (Relative Illumination) diagram of the fourth embodiment of the imaging lens according to the present invention.

FIG. 8F is a modulation transfer function diagram of the fourth embodiment of the imaging lens according to the present invention.

FIG. 8G is a through focus modulation transfer function diagram of the fourth embodiment of the imaging lens according to the present invention.

有負屈光力；一第五透鏡具有正屈光力，此第五透鏡為彎月型透鏡；及一第六透鏡具有正屈光力，此第六透鏡包括一凹面朝向像側；其中第一透鏡、第二透鏡、第三透鏡、第四透鏡、第五透鏡及第六透鏡沿著一光軸從物側至像側依序排列；其中第三透鏡與第四透鏡之間包括一空氣間隔。 The present invention provides an imaging lens, comprising: a first lens with negative refractive power, the first lens includes a concave surface facing an image side; a second lens has positive refractive power, and the second lens includes a convex surface facing an object side; a third lens has positive refractive power; a fourth lens has

There is negative refractive power; a fifth lens has positive refractive power, and the fifth lens is a meniscus lens; and a sixth lens has positive refractive power, and the sixth lens includes a concave surface facing the image side; wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are arranged in sequence along an optical axis from the object side to the image side; wherein an air gap is included between the third lens and the fourth lens.

In the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens of the aforementioned imaging lens, any two adjacent lenses can have an air gap on the optical axis; that is, the imaging lens can have six single non-cemented lenses. Since the manufacturing process of cemented lenses is more complicated than that of non-cemented lenses, especially the cemented surface of the two lenses must have a high-precision curved surface in order to achieve a high degree of adhesion when the two lenses are cemented together. In the process of gluing, misalignment may also cause poor adhesion, which affects the overall optical imaging quality. Therefore, in the imaging lens of the present invention, there can be an air gap between any two adjacent lenses on the optical axis, which can effectively avoid problems caused by cemented lenses.

Please refer to Table 1, Table 3, Table 5 and Table 7 below, wherein Table 1, Table 3, Table 5 and Table 7 are the relevant parameter tables of the lenses according to the first embodiment to the fourth embodiment of the imaging lens of the present invention.

Figures 1, 3, 5, and 7 are schematic diagrams of the lens configurations of the first, second, third, and fourth embodiments of the imaging lens of the present invention, in which the first lenses L11, L21, L31, and L41 have negative refractive power and are made of glass. The image sides S12, S22, S32, and S42 are concave surfaces, and the object sides S11, S21, S31, and S41 and the image sides S12, S22, S32, and S42 are all spherical surfaces. .

The second lenses L12, L22, L32, L42 have positive refractive power and are made of glass material. The object sides S13, S23, S33, S43 are convex, and the object sides S13, S23, S33, S43 and image sides S14, S24, S34, S44 are all spherical surfaces.

The third lenses L13, L23, L33, L43 are biconvex lenses with positive refractive power, made of glass material, the object sides S15, S25, S35, S45 are convex, the image sides S16, S26, S36, S46 are convex, the object sides S15, S25, S35, S45 and the image sides S16, S26, S36, S46 are all spherical surfaces.

The fourth lenses L14, L24, L34, and L44 are biconcave lenses with negative refractive power and are made of glass. The object sides S18, S28, S38, and S48 are concave, and the image sides S19, S29, S39, and S49 are concave.

The fifth lens L15, L25, L35, L45 is a meniscus lens with positive refractive power, made of glass material, the object side S110, S210, S310, S410 is concave, the image side S111, S211, S311, S411 is convex, the object side S110, S210, S310, S410 and the image side S111, S211, S31 1. S411 is spherical surface.

The sixth lens L16, L26, L36, L46 is a meniscus lens with positive refractive power, made of glass material, the object side S112, S212, S312, S412 is convex, the image side S113, S213, S313, S413 is concave, the object side S112, S212, S312, S412 and the image side S113, S213, S31 3. S413 is spherical surface.

In addition, imaging lenses 1, 2, 3, and 4 meet at least one of the following conditions: 120<Vd ₁ +Vd ₃ <140 (1)

0.4<(f ₃ +f ₄ )/f<0.62 (2)

-7<R ₂₂ /R ₂₁ <48 (3)

6mm<f ₄ +f ₆ <12mm (4)

3.9<TTL/BFL<6 (5)

0.05<f ₁₂₃ /f ₄₅₆ <0.22 (6)

其中，Vd ₁為第一實施例至第四實施例中，第一透鏡L11、L21、L31、L41之一阿貝係數，Vd ₃為第一實施例至第四實施例中，第三透鏡L13、L23、L33、L43之一阿貝係數，f ₃為第一實施例至第四實施例中，第三透鏡L13、L23、L33、L43之一有效焦距，f ₄為第一實施例至第四實施例中，第四透鏡L14、L24、L34、L44之一有效焦距，f ₆為第一實施例至第四實施例中，第六透鏡L16、L26、L36、L46之一有效焦距，f為第一實施例至第四實施例中，成像鏡頭1、2、3、4之一有效焦距，f ₁₂₃為第一實施例至第四實施例中，第一透鏡L11、L21、L31、L41、第二透鏡L12、L22、L32、L42及第三透鏡L13、L23、L33、L43之一組合有效焦距，f ₄₅₆為第一實施例至第四實施例中，第四透鏡L14、L24、L34、L44、第五透鏡L15、L25、L35、L45及第六透鏡L16、L26、L36、L46之一組合有效焦距，R ₂₁為第一實施例至第四實施例中，第二透鏡L12、L22、L32、L42之物側面S13、S23、S33、S43之一曲率半徑，R ₂₂為第一實施例至第四實施例中，第二透鏡L12、L22、L32、L42之像側面S14、S24、S34、S44之一曲率半徑，TTL為第一實施例至第四實施例中，第一透鏡L11、L21、L31、L41之物側面S11、S21、S31、S41分別至成像面IMA1、IMA2、IMA3、IMA4於光軸OA1、OA2、OA3、OA4上之一間距，BFL為第一實施例至第四實施例中，第六透鏡L16、L26、L36、L46之像側面S113、S213、S313、S413分別至成像面IMA1、IMA2、IMA3、IMA4於光軸OA1、OA2、OA3、OA4上之一間距。 The imaging lenses 1, 2, 3, and 4 can effectively reduce the aperture value, effectively improve the resolution, effectively resist environmental temperature changes, effectively correct aberrations, and effectively correct chromatic aberrations.

When the condition (1) is satisfied: 120<Vd ₁ +Vd ₃ <140, the chromatic aberration can be effectively reduced and the imaging quality can be improved.

When the condition (2): 0.4<(f ₃ +f ₄ )/f<0.62 is satisfied, the processing sensitivity can be effectively reduced and the quality can be improved.

When the condition (3): -7<R ₂₂ /R ₂₁ <48 is satisfied, the sensitivity of the second lens can be effectively reduced and the quality can be improved.

When the condition (5) is satisfied: 3.9<TTL/BFL<6, a longer back focal length can be obtained, which is beneficial to the assembly of the imaging lens.

The first embodiment of the imaging lens of the present invention will now be described in detail. 1, the imaging lens 1 includes a first lens L11, a second lens L12, a third lens L13, an aperture ST1, a fourth lens L14, a fifth lens L15, a sixth lens L16, a filter OF1 and a protective glass CG1 along an optical axis OA1 from an object side to an image side. During imaging, the light from the object side is finally imaged on an imaging surface IMA1. According to the first to eighth paragraphs of [implementation mode], wherein:

The first lens L11 is a biconcave lens, and its object side S11 is concave;

The second lens L12 is a biconvex lens, and its image side S14 is a convex surface;

The object side S114 and the image side S115 of the optical filter OF1 are both planes;

The object side S116 and the image side S117 of the protective glass CG1 are both plane;

Utilizing the above lens, the aperture ST1 and the design satisfying at least one of the conditions (1) to (6), the imaging lens 1 can effectively reduce the aperture value, effectively improve the resolution, effectively resist changes in ambient temperature, effectively correct aberrations, and effectively correct chromatic aberrations.

Table 1 is a table of relevant parameters of each lens of the imaging lens 1 in FIG. 1 .

Table 2 shows the relevant parameter values of the imaging lens 1 of the first embodiment and the calculated values corresponding to the conditions (1) to (6). It can be seen from Table 2 that the imaging lens 1 of the first embodiment can all meet the requirements of the conditions (1) to (6).

In addition, the optical performance of the imaging lens 1 of the first embodiment can also meet the requirements. It can be seen from FIG. 2A that the field curvature of the imaging lens 1 of the first embodiment is between -0.035 mm and 0.04 mm. It can be seen from FIG. 2B that the distortion of the imaging lens 1 of the first embodiment is between -10% and 0%. It can be seen from FIG. 2C that the imaging lens 1 of the first embodiment has a modulation transfer function value between 0.27 and 1.0.

It is obvious that the field curvature and distortion of the imaging lens 1 of the first embodiment can be effectively corrected, and the resolution of the lens can also meet the requirements, thereby obtaining better optical performance.

Please refer to FIG. 3 . FIG. 3 is a schematic diagram of lens configuration according to the second embodiment of the imaging lens of the present invention. The imaging lens 2 includes a first lens L21, a second lens L22, a third lens L23, an aperture ST2, a fourth lens L24, a fifth lens L25, a sixth lens L26, a filter OF2 and a protective glass CG2 along an optical axis OA2 from an object side to an image side. During imaging, the light from the object side is finally imaged on an imaging surface IMA2. According to the first to eighth paragraphs of [implementation mode], wherein:

The first lens L21 is a biconcave lens, and its object side surface S21 is concave;

The second lens L22 is a biconvex lens, and its image side S24 is a convex surface;

The object side S214 and the image side S215 of the optical filter OF2 are both planes;

The object side S216 and the image side S217 of the protective glass CG2 are both plane;

Utilizing the above lens, the aperture ST2 and the design satisfying at least one of the conditions (1) to (6), the imaging lens 2 can effectively reduce the aperture value, effectively improve the resolution, effectively resist changes in ambient temperature, effectively correct aberrations, and effectively correct chromatic aberrations.

Table 3 is a table of relevant parameters of each lens of the imaging lens 2 in Fig. 3 .

Table 4 shows the relevant parameter values of the imaging lens 2 of the second embodiment and the calculated values corresponding to the conditions (1) to (6). It can be seen from Table 4 that the imaging lens 2 of the second embodiment can all meet the requirements of the conditions (1) to (6).

In addition, the optical performance of the imaging lens 2 of the second embodiment can also meet the requirements. It can be seen from FIG. 4A that the field curvature of the imaging lens 2 of the second embodiment is between -0.04 mm and 0.06 mm. It can be seen from FIG. 4B that the distortion of the imaging lens 2 of the second embodiment is between -10% and 0%. It can be seen from FIG. 4C that the modulation transfer function value of the imaging lens 2 of the second embodiment is between 0.54 and 1.0.

It is obvious that the field curvature and distortion of the imaging lens 2 of the second embodiment can be effectively corrected, and the resolution of the lens can also meet the requirements, thereby obtaining better optical performance.

Please refer to FIG. 5 . FIG. 5 is a schematic diagram of the lens configuration of the third embodiment of the imaging lens according to 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 fifth lens L35, a sixth lens L36, a filter OF3 and a protective lens from an object side to an image side along an optical axis OA3. Protective glass CG3. During imaging, the light from the object side is finally imaged on an imaging surface IMA3. According to the first to eighth paragraphs of [implementation mode], wherein:

The first lens L31 is a biconcave lens, and its object side surface S31 is concave;

The second lens L32 is a biconvex lens, and its image side S34 is a convex surface;

The object side S314 and the image side S315 of the optical filter OF3 are both planes;

The object side S316 and the image side S317 of the protective glass CG3 are both plane;

Utilizing the above-mentioned lens, the aperture ST3 and the design satisfying at least one of the conditions (1) to (6), the imaging lens 3 can effectively reduce the aperture value, effectively improve the resolution, effectively resist changes in ambient temperature, effectively correct aberrations, and effectively correct chromatic aberrations.

Table 5 is a table of relevant parameters of each lens of the imaging lens 3 in FIG. 5 .

Table 6 shows the relevant parameter values of the imaging lens 3 of the third embodiment and the calculated values corresponding to the conditions (1) to (6). It can be seen from Table 6 that the imaging lens 3 of the third embodiment can all meet the requirements of the conditions (1) to (6).

In addition, the optical performance of the imaging lens 3 of the third embodiment can also meet the requirements. It can be seen from FIG. 6A that the field curvature of the imaging lens 3 of the third embodiment is between -0.04 mm and 0.05 mm. It can be seen from FIG. 6B that the distortion of the imaging lens 3 of the third embodiment is between -12% and 0%. It can be seen from FIG. 6C that the modulation transfer function value of the imaging lens 3 of the third embodiment is between 0.52 and 1.0.

It is obvious that the field curvature and distortion of the imaging lens 3 of the third embodiment can be effectively corrected, and the resolution of the lens can also meet the requirements, thereby obtaining better optical performance.

Please refer to FIG. 7 . FIG. 7 is a schematic diagram of the lens configuration of the fourth embodiment of the imaging lens according to the present invention. The imaging lens 4 includes a first lens L41, a second lens L42, a third lens L43, an aperture ST4, a fourth lens L44, a fifth lens L45, a sixth lens L46, a filter OF4 and a protective glass CG4 along an optical axis OA4 from an object side to an image side. During imaging, the light from the object side is finally imaged on an imaging surface IMA4. According to the first to eighth paragraphs of [implementation mode], wherein:

The first lens L41 is a meniscus lens, and its object side surface S41 is a convex surface;

The second lens L42 is a meniscus lens, and its image side S44 is concave;

The object side S414 and the image side S415 of the optical filter OF4 are both planes;

The object side S416 and the image side S417 of the protective glass CG4 are both plane;

Utilizing the above-mentioned lens, the aperture ST4 and the design satisfying at least one of the conditions (1) to (6), the imaging lens 4 can effectively reduce the aperture value, effectively improve the resolution, effectively resist environmental temperature changes, effectively correct aberrations, and effectively correct chromatic aberrations.

Table 7 is a table of relevant parameters of each lens of the imaging lens 4 in FIG. 7 .

Table 8 shows the relevant parameter values of the imaging lens 4 of the fourth embodiment and the calculated values corresponding to the conditions (1) to (6). As can be seen from Table 8, the imaging lens 4 of the fourth embodiment can all meet the requirements of the conditions (1) to (6).

In addition, the optical performance of the imaging lens 4 of the fourth embodiment can also meet the requirements. It can be seen from FIG. 8A that the longitudinal aberration of the imaging lens 4 of the fourth embodiment is between -0.01 mm and 0.035 mm. It can be seen from FIG. 8B that the field curvature of the imaging lens 4 of the fourth embodiment is between -0.025mm and 0.035mm. It can be seen from FIG. 8C that the distortion of the imaging lens 4 of the fourth embodiment is between -2% and 0%. It can be seen from FIG. 8D that the lateral chromatic aberration of the imaging lens 4 of the fourth embodiment is between -1.0 μm and 2.5 μm. It can be seen from FIG. 8E that the relative illuminance of the imaging lens 4 of the fourth embodiment is between 0.85 and 1.0. It can be seen from FIG. 8F that the modulation transfer function value of the imaging lens 4 of the fourth embodiment is between 0.51 and 1.0. It can be seen from FIG. 8G that the imaging lens 4 of the fourth embodiment has a modulation transfer function value between 0.0 and 0.90 when the focus shift is between -0.05mm and 0.05mm.

It is obvious that the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 4 of the fourth embodiment can be effectively corrected, and the relative illuminance, lens resolution, and focal depth can also meet the requirements, thereby obtaining better optical performance.

Although the present invention has been disclosed above in terms of implementation, it is not intended to limit the present invention. Any person familiar with the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the scope of the appended patent application.

1: Imaging lens

L11: first lens

L12: second lens

L13: third lens

L14: Fourth lens

L15: fifth lens

L16: sixth lens

ST1: Aperture

OA1: optical axis

OF1: filter

CG1: Protective glass

IMA1: imaging surface

S11: The object side of the first lens

S12: The first lens image side

S13: Second lens object side

S14: The second lens image side

S15: third lens object side

S16: The third lens image side

S17: Aperture surface

S18: The fourth lens object side

S19: The fourth lens image side

S110: The object side of the fifth lens

S111: The fifth lens image side

S112: The object side of the sixth lens

S113: The side image of the sixth lens

S114: Filter object side

S115: Filter image side

S116: Protect the side of the glass object

S117: Protective glass like side

Claims (10)

A kind of imaging lens, comprises: a first lens has negative refractive power, and this first lens includes a concave surface toward an image side; A second lens has positive refractive power, and this second lens includes a convex surface toward an object side; A third lens has positive refractive power, and this third lens includes a convex surface toward this image side; A fourth lens has negative refractive power; A fifth lens has positive refractive power, and this fifth lens is a meniscus lens; The lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially arranged along an optical axis from the object side to the image side; wherein an air space is included between the third lens and the fourth lens. An imaging lens, comprising: a first lens with negative refractive power, the first lens includes a concave surface toward an image side; a second lens has positive refractive power, the second lens includes a convex surface toward an object side; a third lens has positive refractive power; a fourth lens has negative refractive power, and the fourth lens includes a concave surface toward the object side; a fifth lens has positive refractive power, and the fifth lens is a meniscus lens; The lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially arranged along an optical axis from the object side to the image side; wherein an air space is included between the third lens and the fourth lens. The imaging lens described in any one of the claims from item 1 to item 2 of the scope of the patent application, wherein: The first lens further includes a convex surface facing the object side; and the second lens further includes a concave surface facing the image side. An imaging lens comprising: a first lens with negative refractive power, the first lens includes a concave surface towards an object side and another concave surface towards an image side; a second lens has positive refractive power, and the second lens includes a convex surface towards the object side; a third lens has positive refractive power; a fourth lens has negative refractive power; a fifth lens has positive refractive power, and the fifth lens is a meniscus lens; The lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially arranged along an optical axis from the object side to the image side; wherein an air space is included between the third lens and the fourth lens. The imaging lens described in claim 1, claim 2 or claim 4, wherein the second lens further includes a convex surface facing the image side. The imaging lens described in item 1, item 2 or item 4 of the scope of the patent application, wherein the third lens is a biconvex lens, the fourth lens is a biconcave lens, and the fifth lens includes a concave surface facing the object side and a convex surface facing the image side. In the imaging lens described in claim 1, claim 2 or claim 4, the sixth lens further includes a convex surface facing the object side. The imaging lens described in item 1, item 2 or item 4 of the scope of the patent application further includes an aperture disposed between the third lens and the fourth lens. The imaging lens described in item 1, item 2 or item 4 of the scope of the patent application, wherein the first lens, the second lens and the third lens include at least one glass spherical lens, and the fourth lens, the fifth lens and the sixth lens include at least one glass spherical lens. The imaging lens as described in item 1, item 2 or item 4 of the scope of the patent application, wherein the imaging lens at least satisfies any of the following conditions: 0.4<(f₃+ f₄)/f<0.62; 6mm<f₄+f₆<12mm; 0.05<f₁₂₃/f₄₅₆<0.22; 3.9<TTL/BFL<6; -7<R_{twenty two}/R_{twenty one}<48; 120<Vd₁+Vd₃<140; where, f is the effective focal length of one of the imaging lenses, f₃is the effective focal length of one of the third lenses, f₄is the effective focal length of one of the fourth lenses, f₆is the effective focal length of one of the sixth lenses, f₁₂₃is the combined effective focal length of one of the first lens, the second lens and the third lens, f₄₅₆is the combined effective focal length of one of the fourth lens, the fifth lens, and the sixth lens, TTL is the distance from the object side of the first lens to an imaging plane on the optical axis, BFL is the distance from the image side of the sixth lens to the imaging plane on the optical axis, R_{twenty one}is the radius of curvature of one object side surface of the second lens, R_{twenty two}is the radius of curvature of one of the image sides of the second lens, Vd₁is the Abbe coefficient of one of the first lenses, Vd₃is the Abbe number of one of the third lenses.

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