CN103293635A - Imaging lens - Google Patents

An imaging lens sequentially comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with positive focal power, a fifth lens with negative focal power and an imaging face from an object side to the imaging face. The imaging lens satisfies the following equation that the ratio of D and TTL is larger than 0.94; D is the diameter of the largest imaging circle on the imaging face; TTL is the length of the whole imaging lens. The imaging lens satisfies the conditions and the imaging quality of the imaging lens is small in length, high in resolution ratio and low in chromatic aberration.

Imaging lens

Technical field

The present invention relates to a kind of imaging technique, relate in particular to a kind of imaging lens.

Background technology

Along with the day of intelligent mobile phone is also popularized, the consumer begins to thirst for, mobile phone except functional complete, and need to possess compact characteristics, in order to can be convenient for carrying.Therefore, the compact of mobile phone limited the space of placing camera module, and then needs the imaging lens of " low length " and " the exiting surface effective diameter is little ", can reach minimum with the cumulative volume of guaranteeing camera module.

One of be used at present on the mobile phone hundred ginsengs and pick up the imaging lens of the above camera module of ten thousand pixels (13M), can use autofocus motor (Auto Focus Actuator) to drive imaging lens mostly moves, allow the photo taken from distant view end (infinity) to close shot end (100mm) can both be clear, this is because the consumer wishes that the landscape that mobile phone can photograph shines (distant view end), and the personage that can photograph is again shone and major part shines (middle scape end), even can do business card identification (close shot end, usually the distance of business card identification is about 100mm), therefore, the imaging lens that just needs " far and near scape image quality is taken into account ".

Summary of the invention

In view of this, be necessary to provide a kind of imaging lens with the little high resolving power of length, low aberration.

A kind of imaging lens, it comprises to imaging surface successively from the thing side: the 3rd lens, that second lens, that first lens, with positive light coke have a negative power have a positive light coke have the 5th lens and the imaging surface that the 4th lens, of positive light coke have negative power.Described imaging lens meets the following conditions: D/TTL〉0.94; Wherein, D is maximum imaging circular diameter on the imaging surface; TTL is the length of whole imaging lens.

Satisfy the imaging lens of above-mentioned condition, have the image quality of the little high resolving power of length, low aberration.

Description of drawings

Fig. 1 is the structural representation of imaging lens provided by the invention.

The imaging lens that Fig. 2 provides for first embodiment of the invention is at the spherical aberration performance diagram of distant view end.

The imaging lens that Fig. 3 provides for first embodiment of the invention is at the curvature of field performance diagram of distant view end.

The imaging lens that Fig. 4 provides for first embodiment of the invention is at the distortion performance curve map of distant view end.

The imaging lens that Fig. 5 provides for first embodiment of the invention is at the modulation transfer function performance diagram of distant view end.

The imaging lens that Fig. 6 provides for first embodiment of the invention is at the spherical aberration performance diagram of close shot end.

The imaging lens that Fig. 7 provides for first embodiment of the invention is at the curvature of field performance diagram of close shot end.

The imaging lens that Fig. 8 provides for first embodiment of the invention is at the distortion performance curve map of close shot end.

The imaging lens that Fig. 9 provides for first embodiment of the invention is at the modulation transfer function performance diagram of close shot end.

The imaging lens that Figure 10 provides for second embodiment of the invention is at the spherical aberration performance diagram of distant view end.

The imaging lens that Figure 11 provides for second embodiment of the invention is at the curvature of field performance diagram of distant view end.

The imaging lens that Figure 12 provides for second embodiment of the invention is at the distortion performance curve map of distant view end.

The imaging lens that Figure 13 provides for second embodiment of the invention is at the modulation transfer function performance diagram of distant view end.

The imaging lens that Figure 14 provides for second embodiment of the invention is at the spherical aberration performance diagram of close shot end.

The imaging lens that Figure 15 provides for second embodiment of the invention is at the curvature of field performance diagram of close shot end.

The imaging lens that Figure 16 provides for second embodiment of the invention is at the distortion performance curve map of close shot end.

The imaging lens that Figure 17 provides for second embodiment of the invention is at the modulation transfer function performance diagram of close shot end.

The main element symbol description

Following embodiment will further specify the present invention in conjunction with above-mentioned accompanying drawing.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail.

See also Fig. 1, a kind of imaging lens 100 provided by the invention, it comprises successively from thing side to imaging surface: first lens L1 with positive light coke, second lens L2 with negative power, one have the 3rd lens L3 of positive light coke, the 4th a lens L4 with positive light coke, the 5th lens L5, an optical filter 10 and the imaging surface 20 with negative power.

The described first lens L1 extremely comprises first surface S1 and the second surface S2 to described imaging surface 20 protrusions towards thing side protrusion as side successively from the thing side.

The described second lens L2 extremely comprises the 3rd surperficial S3 and the 4th a surperficial S4 to the described second lens L2 inner recess towards object one side protrusion as side successively from the thing side.

Described the 3rd lens L3 extremely comprises one towards the 5th surperficial S5 of object one side protrusion and the 6th surperficial S6 that protrudes to described imaging surface 20 1 sides as side successively from the thing side.

Described the 4th lens L4 extremely comprises the 7th surperficial S7 and the 8th a surperficial S8 to described imaging surface 20 1 sides protrusion to described the 4th lens L4 inner recess as side successively from the thing side.

Described the 5th lens L5 extremely comprises the 9th surperficial S9 and the tenth a surperficial S10 to described the 5th lens L5 inner recess to described the 5th lens L5 inner recess as side successively from the thing side.

The ten two surperficial S12 of described optical filter 10 from the thing side to the 11 surperficial S11 that comprises close thing side as side successively and close described imaging surface 20.Described optical filter 10 is used for filtering through the Infrared of the light of the 5th lens L5.

Described imaging lens 100 also comprises a diaphragm 30.Described diaphragm 30 with respect to diaphragm 30 symmetries, reduces the influence of coma (coma) with the one-piece construction that guarantees imaging lens 100 effectively between the described first lens L1 and the second lens L2; Limit the luminous flux that enters the second lens L2 through the light of the first lens L1 simultaneously, and allow through the light cone behind the second lens L2 more symmetrically, the coma of imaging lens 100 is revised.

In the present embodiment, light after the thing side is incident to the first lens L1, and successively again through described diaphragm 30, the second lens L2, the 3rd lens L3, the 4th lens L4, the 5th lens L5, and optical filter 10 after image in described imaging surface 20.Be appreciated that and as Charged Coupled Device (CCD) or complementary metal oxide semiconductor (CMOS) (CMOS), sentence composition one imaging system in described imaging surface 20 by the image sensor (not shown) is set.

Described imaging lens 100 formula that meets the following conditions:

(1)D/TTL>0.94；

Wherein, D is the maximum imaging circular diameter on the described imaging surface 20; TTL is the length of whole imaging lens 100.

In imaging lens 100 conditionals provided by the present invention, conditional (1) has limited the length overall of imaging lens 100.

Described imaging lens 100 formula that can further meet the following conditions:

(2)D/L>1.21；

Wherein L is the effective diameter of the exiting surface of the tenth surperficial S10.

Conditional (2) has limited the exiting surface effective diameter of described imaging lens 100, makes the overall diameter of described imaging lens 100 can be less than maximum imaging circular diameter, and reaches minimum.

Described imaging lens 100 formula that can further meet the following conditions:

(3)?Z/Y>0；

Wherein, Z is center thickness poor of the curved surface transverse height of described the 8th surperficial S8 and described the 4th lens L4, and Y is the vertical height of the curved surface of described the 8th surperficial S8.

Conditional (3) guarantees that described the 4th lens L4 is easy to ejection formation, makes the plastics that injected by monolateral cast gate can arrive subtend one side easily, and then allows the core shift susceptibility of described imaging lens 100 diminish.

Described imaging lens 100 formula that can further meet the following conditions:

（4）R31/F3>R11/F1>0；

（5）R12/F1<R32/F3<0；

Wherein, R11 is the radius-of-curvature of the first surface S1 of the described first lens L1; R12 is the radius-of-curvature of the second surface S2 of the described first lens L1; R31 is the radius-of-curvature of the 5th surperficial S5 of described the 3rd lens L3; R32 is the radius-of-curvature of the 6th surperficial S6 of described the 3rd lens L3; F1 is the focal length of the described first lens L1; F3 is the focal length of described the 3rd lens L3.

Conditional (4) and (5) make imaging lens 100 have good receipts difference revisal effect.

Described imaging lens 100 formula that can further meet the following conditions:

(6)?R51/F5<R52/F5<0；

Wherein, R51 is the radius-of-curvature of the 9th surperficial S9 of described the 5th lens L5; R52 is the radius-of-curvature of the tenth surperficial S10 of described the 5th lens L5; F5 is the focal length of described the 5th lens L5.

Conditional (6) makes the core shift susceptibility of imaging lens 100 diminish.

Wherein, described first surface S1, second surface S2, the 3rd surperficial S3, the 4th surperficial S4, the 5th surperficial S5, the 6th surperficial S6, the 7th surperficial S7, the 8th surperficial S8, the 9th surperficial S9 and the tenth surperficial S10 all are aspheric surfaces, and satisfy aspheric type formula:

Wherein, z be along optical axis direction highly for the position of h with the surface vertices shift value apart from optical axis for referencial use, c is radius-of-curvature, h is lens height, K is circular cone fixed number (Coin Constant), and Ai is i time asphericity coefficient (i-th order Aspherical Coefficient).

By table 1, table 2, table 3(are seen also hereinafter) the above-mentioned expression formula of data substitution, can obtain the aspherical shape of each lens surface in the imaging lens 100 of first embodiment of the invention.In addition, by the above-mentioned expression formula of data substitution with table 5, table 6, table 7, can know the aspherical shape of each lens surface in the imaging lens 100 of second embodiment of the invention.

Show respectively in following each table by the thing end to the picture end optical surface of arrangement in regular turn, wherein, i represents i lens surface beginning from the thing side; Agreement F/No is the f-number of imaging lens 100; 2 ω are the field angle of imaging lens 100; Ri represents the radius-of-curvature of i lens surface beginning from the thing side; Axial distance between i lens surface to the i+1 lens surface that Di represents to begin from the thing side; Ni represents the refractive index of i lens surface beginning from the thing side; Vi represents the Abbe number of i lens surface beginning from the thing side; Ki represents the quadratic curvature of i lens surface beginning from the thing side.

First embodiment

Each optical module of the imaging lens 100 that first embodiment of the invention provides satisfies table 1 to the condition of table 3.

Table 1

Table 2

Table 3

Table 4

In the present embodiment, D=5.867mm; TTL=5.48mm; Z=0.137mm; Y=1.45mm; L=4.47mm; F1=3.32mm; F3=7.99mm; F5=-2.57mm.

At the distant view end, the spherical aberration of the imaging lens 100 of first embodiment, the curvature of field, distortion, MTF are extremely shown in Figure 5 as Fig. 2 respectively.Particularly, five curves shown in Figure 2 are respectively at F line (wavelength is 486 nanometers (nm)), d line (wavelength is 588nm), C line (wavelength is 654nm), e line (wavelength is 546), g line (wavelength is 436nm), and observed aberration value curve.Can find out that by these five curves aberration value control that 100 pairs of visible lights of imaging lens (wavelength coverage is between the 400nm-700nm) of first embodiment produce is in-0.05mm ~ 0.05mm scope.As shown in Figure 3, curve T and S are respectively meridianal curvature of field (tangential field curvature) family curve and the sagitta of arc curvature of field (sagittal field curvature) family curve.As seen from Figure 3 the meridianal curvature of field value of this imaging lens 100 and sagitta of arc curvature of field value be controlled in-0.05mm ~ 0.05mm scope in.Further, curve shown in Figure 4 is the distortion performance curve of imaging lens 100, and as shown in Figure 4, the optical distortion amount of this imaging lens 100 is controlled in-2.00% ~ 2.00% the scope.As shown in Figure 5, under 1/2 frequency (Nyquist frequency) condition (1/2 frequency of present embodiment (half frequently) is 224lp/mm), the MTF of visual field, center〉55% (shown in curve mc), 0.8 the MTF of visual field〉40% (shown in curve mp), the MTF of all the other visual fields between visual field, center and 0.8 visual field, then between 40% ~ 55% (shown in curve mt).

At the close shot end, the spherical aberration of the imaging lens 100 of first embodiment, the curvature of field, distortion, MTF are extremely shown in Figure 9 as Fig. 6 respectively.Particularly, five curves shown in Figure 6 are respectively at F line (wavelength is 486 nanometers (nm)), d line (wavelength is 588nm), C line (wavelength is 654nm), e line (wavelength is 546), g line (wavelength is 436nm), and observed aberration value curve.Can find out that by these five curves aberration value control that 100 pairs of visible lights of imaging lens (wavelength coverage is between the 400nm-700nm) of first embodiment produce is in-0.05mm ~ 0.05mm scope.As shown in Figure 7, curve T and S are respectively meridianal curvature of field (tangential field curvature) family curve and the sagitta of arc curvature of field (sagittal field curvature) family curve.As seen from Figure 3 the meridianal curvature of field value of this imaging lens 100 and sagitta of arc curvature of field value be controlled in-0.05mm ~ 0.05mm scope in.Further, curve shown in Figure 8 is the distortion performance curve of imaging lens 100, and as shown in Figure 8, the optical distortion amount of this imaging lens 100 is controlled in-2.00% ~ 2.00% the scope.As shown in Figure 9, under 1/2 frequency (Nyquist frequency) condition (1/2 frequency of present embodiment (half frequently) is 224lp/mm), the MTF of visual field, center〉42% (shown in curve mc), 0.8 the MTF of visual field〉14% (shown in curve mp), the MTF of all the other visual fields between visual field, center and 0.8 visual field, then between 14% ~ 42% (shown in curve mt).

Second embodiment

Each optical module of the imaging lens 100 that second embodiment of the invention provides satisfies the condition of table 5, table 6, table 7 and table 8.

Table 5

Table 6

Table 7

Table 8

In the present embodiment, D=5.867mm; TTL=5.66mm; Z=0.121mm; Y=1.44mm; L=4.42mm; F1=3.55mm; F3=7.78mm; F5=-2.63mm.

At the distant view end, the spherical aberration of described imaging lens 100, the curvature of field, distortion, MTF are extremely shown in Figure 13 as Figure 10 respectively.Particularly, five curves shown in Figure 10 are respectively at F line (wavelength is 486 nanometers (nm)), d line (wavelength is 588nm), C line (wavelength is 654nm), e line (wavelength is 546), g line (wavelength is 436nm), and observed aberration value curve.Can find out that by these five curves aberration value control that 100 pairs of visible lights of imaging lens (wavelength coverage is between the 400nm-700nm) of second embodiment produce is in-0.05mm ~ 0.05mm scope.As shown in figure 11, curve T and S are respectively meridianal curvature of field (tangential field curvature) family curve and the sagitta of arc curvature of field (sagittal field curvature) family curve.As seen from Figure 11 the meridianal curvature of field value of this imaging lens 100 and sagitta of arc curvature of field value be controlled in-0.05mm ~ 0.05mm scope in.Further, curve shown in Figure 12 is the distortion performance curve of imaging lens 100, and as shown in Figure 12, the optical distortion amount of the imaging lens 100 of this second embodiment is controlled in-2.00% ~ 2.00% the scope.As shown in figure 13, under 1/2 frequency (Nyquist frequency) condition (1/2 frequency of present embodiment (half frequently) is 224lp/mm), the MTF of visual field, center〉55% (shown in curve mc), 0.8 the MTF of visual field〉40% (shown in curve mp), the MTF of all the other visual fields between visual field, center and 0.8 visual field, then between 40% ~ 55% (shown in curve mt).

At the close shot end, the spherical aberration of the described imaging lens 100 of second embodiment, the curvature of field, distortion, MTF are extremely shown in Figure 17 as Figure 14 respectively.Particularly, five curves shown in Figure 14 are respectively at F line (wavelength is 486 nanometers (nm)), d line (wavelength is 588nm), C line (wavelength is 654nm), e line (wavelength is 546), g line (wavelength is 436nm), and observed aberration value curve.Can find out that by these five curves aberration value control that 100 pairs of visible lights of imaging lens (wavelength coverage is between the 400nm-700nm) of first embodiment produce is in-0.05mm ~ 0.05mm scope.As shown in figure 15, curve T and S are respectively meridianal curvature of field (tangential field curvature) family curve and the sagitta of arc curvature of field (sagittal field curvature) family curve.As seen from Figure 15 the meridianal curvature of field value of this imaging lens 100 and sagitta of arc curvature of field value be controlled in-0.05mm ~ 0.05mm scope in.Further, curve shown in Figure 16 is the distortion performance curve of the imaging lens 100 of second embodiment, and as shown in Figure 16, the optical distortion amount of the imaging lens 100 of second embodiment is controlled in-2.00% ~ 2.00% the scope.As shown in figure 17, under 1/2 frequency (Nyquist frequency) condition (1/2 frequency of present embodiment (half frequently) is 224lp/mm), the MTF of visual field, center〉42% (shown in curve mc), 0.8 the MTF of visual field〉14% (shown in curve mp), the MTF of all the other visual fields between visual field, center and 0.8 visual field, then between 14% ~ 42% (shown in curve mt).

Satisfy the imaging lens of above-mentioned condition, have the image quality of the little high resolving power of length, low aberration.

In addition, those skilled in the art can also do other variation in spirit of the present invention, and certainly, the variation that these are done according to spirit of the present invention all should be included within the present invention's scope required for protection.