CN103576290B - A kind of wide-angle lens - Google Patents

Abstract

The invention provides a kind of wide-angle lens, comprise the front lens group with negative power from the object side to the image side successively, diaphragm, there is the rear lens group of positive light coke, described front lens group comprises the first lens successively from object space side, second lens, 3rd lens, described first lens are convex diverging meniscus lenses to object space, described second lens are the lens of negative bent moon or concave-concave, described 3rd lens are the positive power lens of biconvex, described rear lens group comprises the 4th lens successively from object space side, 5th lens, 6th lens, 4th lens and the 5th lens form a balsaming lens, described 4th lens have positive light coke, described 5th lens have negative power, described 6th lens are the lens of the positive light coke of biconvex, wherein the second lens are in the 6th lens, at least comprising four lens is non-spherical lenses.Described invention can realize cost low, lightweight, distort little, size is little, high pass optical property and meet high definition requirement.

Description

A kind of wide-angle lens

Technical field

The present invention relates to a kind of wide-angle lens system, be particularly suitable for the more severe outdoor monitoring of environment and vehicle-mounted wide-angle lens.

Background technology

Current high definition wide-angle lens generally adopts 5 to 8 sheet glass lens compositions, if China Patent No. is the wide-angle lens of 200710201261, just adopt 6 sheet glass lens compositions, but this wide-angle lens not only heavier-weight, and after field angle is more than 90 °, distortion will be very serious.For this reason, also the wide-angle lens of enterprise development is had to adopt aspheric surface technology, to subtract amount distortion, if U.S. Patent number is the wide-angle lens of US2009251801A1, just adopt 6 lens compositions, wherein containing 2 is non-spherical lens, although can correct optical distortion, but Lens is comparatively large, and it is higher to grow up.

Summary of the invention

The invention provides a kind of camera lens wide-angle lens, solve wide-angle lens field angle more than 90 ° after the serious problem of distortion, its technical scheme is as described below:

A kind of wide-angle lens, comprise the front lens group with negative power from the object side to the image side successively, diaphragm, there is the rear lens group of positive light coke, described front lens group comprises the first lens successively from object space side, second lens, 3rd lens, described first lens are convex diverging meniscus lenses to object space, described second lens are the lens of negative bent moon or concave-concave, described 3rd lens are the positive power lens of biconvex, described rear lens group comprises the 4th lens successively from object space side, 5th lens, 6th lens, 4th lens and the 5th lens form a balsaming lens, described 4th lens have positive light coke, described 5th lens have negative power, described 6th lens are the lens of the positive light coke of biconvex, wherein the second lens are in the 6th lens, at least comprising four lens is non-spherical lenses.

And described camera lens second lens and rear lens group meet condition formula below:

-after 1.0 >=F/F2 >=-1.5

Wherein F2 represents the focal length value of the second lens, represents the focal length value of rear lens group after F.

The focal length value of the second lens element and rear lens group will to satisfy condition after formula-1.0 >=F/F2 >=-1.5, because of when after F/F2 >-1.0 time, the negative power of the second lens is excessive, the positive light coke of rear lens group is too small, thus it is excessive to make whole optical system can embody local negative power, the effect of the rear burnt BFL " pyrocondensation cold expanding " of optical system can be caused (namely under the high temperature conditions, the rear burnt BFL of camera lens can shorten, under cryogenic, the rear burnt BFL of camera lens can be elongated, do not meet the condition that camera uses); When after F/F2 <-1.5 time, the negative power of the second lens is too small, the positive light coke of rear lens group is excessive, thus make the local positive light coke of whole optical system excessive, the effect that the rear burnt BFL of optical system can be caused " to expand with heat and contract with cold " is too obvious, thus affects camera imaging definition in the temperature range of-40 DEG C ~+85 DEG C.

Further, described camera lens meets condition formula below

° wherein, FOV represents total field angle of described camera lens in 220 ° >=FOV >=130.

Further, described first lens meet relational expression

Nd >=1.65, Vd >=45 wherein Nd are refractive index, and Vd is Abbe constant.

Such first lens effectively can import the light of more than 130 ° of field angle and reduce the bore of first lens, to avoid volume excessive, and the requirement of the formula that satisfies condition (d/h)/FOV≤0.025.

Further, described 3rd lens meet condition formula below:

Nd≥1.55，Vd≤31

Wherein Nd is refractive index, and Vd is Abbe constant.

Described 3rd lens can assemble the light that the first two negative-power lenses is come fast, and the value of chromatism in high chromatic dispersion material energy effective compensation optical system.

Further, described camera lens meets condition formula below

TTL/EFL≤20

Wherein TTL is the distance of described camera lens first lens object space side outermost point to imaging surface, and EFL is total focal length value of described wide-angle lens.

Further, described second lens and rear lens group meet condition formula below:

-after 1.0 >=F/F2 >=-1.5

Further, the maximum clear aperture of described first lens meets following condition formula with corresponding imaging image height, field angle:

(d/h)/FOV≤0.025

Wherein FOV represents the maximum field of view angle of wide-angle lens, and d represents the maximum clear aperture of the first lens corresponding to maximum field of view angle towards object space convex surface, and h represents the imaging image height corresponding to maximum field of view angle.

Further, described 4th lens and the 5th lens adopt glue to carry out bonding joint formation lens subassembly, and composition surface convex surface facing image side.

Further, described 4th lens and the 5th lens adopt plastic material, and composition surface meets following condition formula:

θ≤60°，|R|≤Φ/2

Wherein θ is the tangent line of any point on composition surface and the angle of optical axis, and R is the center curvature radius on composition surface, and Φ is the light effective aperture on composition surface.

Further, described camera lens meets condition formula below:

BFL/EFL≥2.0

Wherein BFL is the distance of the 6th lens image side outermost point to imaging surface of described wide-angle lens, and EFL is the focal length value of described wide-angle lens.

In a word, the second lens, to the 6th lens five eyeglasses, need reasonably distribute focal power and control within the scope of above-mentioned condition formula, to reach good temperature characterisitic requirement simultaneously.Meanwhile, in order to improve temperature characterisitic effect further, also the material of the 3rd lens can be adopted glass material (because the temperature characterisitic of glass material is better than plastic resin material).

First lens of optical lens adopt glass mirror, and energy available protecting optical lens is scratch resistant scrape along opposing rugged environment variable effect in use, and the 4th lens and the 5th lens adopt bond layout, effectively to improve the aberration of optical system.The composition surface simultaneously controlling cemented lens assembly meet θ≤60 ° and | the condition formula of R| >=Φ/2, effectively to control the generation of senior aberration, thus be beneficial to the logical luminous energy power (aperture FNO≤2.2) and resolving power that improve whole optical system, and effectively reduce processing and the gluing technique requirement on composition surface.

Another important feature of the present invention is keeping still having longer rear lens focus BFL under the shorter condition of camera lens overall length TTL, the dimensional requirement that during to meet camera design, imageing sensor periphery electronic devices and components are larger, simultaneously, because the longer distance making lens element and optical filter leave imageing sensor of BFL is farther, effectively can reduce the surface cleanliness requirement to each lens element and optical filter, the assembling of easier camera is produced.

Use wide-angle lens provided by the invention, can realize cost low, lightweight, distort little, size is little, high pass optical property and meet high definition require wide-angle lens, simultaneously because have employed more plastic aspheric lens, lighter weight and lower cost can be kept.And can ensure still to keep more perfect imaging definition in the temperature range of-40 DEG C ~+85 DEG C, be specially adapted to outdoor monitoring and in-vehicle camera system.

Accompanying drawing explanation

Fig. 1 is the structural representation of the embodiment 1 of wide-angle lens provided by the invention;

Fig. 2 is the chromatic curve figure of the embodiment 1 of wide-angle lens provided by the invention;

Fig. 3 is the astigmatism curve map of the embodiment 1 of wide-angle lens provided by the invention;

Fig. 4 is the distortion curve figure of the embodiment 1 of wide-angle lens provided by the invention;

Fig. 5 is the structural representation of the embodiment 2 of wide-angle lens provided by the invention;

Fig. 6 is the chromatic curve figure of the embodiment 2 of wide-angle lens provided by the invention;

Fig. 7 is the astigmatism curve map of the embodiment 2 of wide-angle lens provided by the invention;

Fig. 8 is the distortion curve figure of the embodiment 2 of wide-angle lens provided by the invention.

Embodiment

Embodiments of the invention 1 as shown in Figures 1 to 4, described camera lens comprise successively from the object side to the image side there is negative power front lens group, diaphragm, there is the rear lens group of positive light coke, described front lens group comprises the first lens L1, the second lens L2, the 3rd lens L3 successively from object space side, described rear lens group comprises the 4th lens L4, the 5th lens L5, the 6th lens L6 successively from object space side.

As shown in Figure 1, described camera lens is followed successively by the first lens L1, the second lens L2, the 3rd lens L3, diaphragm r7, the 4th lens L4, the 5th lens L5, the 6th lens L6, color filter GF, imaging surface IMA by thing side to image side.

First lens L1 is the diverging meniscus lens with negative focal power, the glass lens element of to be two sides be all sphere; Second lens L2 is the lens with negative focal power, be two sides is all aspheric plastic lens elements; 3rd lens L3 is the biconvex lens with positive focal power, the glass lens element of to be two sides be all sphere; 4th lens L4 is the biconvex lens with positive focal power, be two sides is all aspheric plastic lens elements; 5th lens L5 is the diverging meniscus lens with negative focal power, be two sides is all aspheric plastic lens elements; And L4 and L5 is combined into a balsaming lens; 6th lens L6 is the biconvex lens with positive focal power, be two sides is all aspheric plastic lens elements.

Fig. 2 to Fig. 4 is the optical performance curve figure corresponding to embodiment 1, and wherein Fig. 2 is chromatic curve figure (also can be spherical aberration curve map), by commonly use F, d, C tri-the wavelength of coloured light represent, unit is mm.Fig. 3 is astigmatism curve map, by commonly use F, d, C tri-the wavelength of coloured light represent, unit is mm.Fig. 4 is distortion curve figure, represents the distortion sizes values in different field angle situation, and unit is %.

In embodiment 1, the whole focal length value of this wide-angle lens is F, f-number is FNO, field angle is 2 ω, camera lens overall length TTL, and by object space side, by each minute surface number consecutively, the minute surface of the first lens L1 is r1, r2, and the minute surface of the second lens L2 is r3, r4, the minute surface of the 3rd lens L3 is r5, r6, diaphragm face is r7, and the minute surface of the 4th lens L4 and the 5th lens L5 is r8, r9, r10, and the minute surface of the 6th lens L6 is r11, r12, the minute surface of color filter GF is r13, r14, and the formula of aspherical mirror is:

$Z\left(h\right)=\frac{{\mathrm{ch}}^2}{1+\sqrt{1-(1+k)c^2{h}^2}}+{\mathrm{Ah}}^4+{\mathrm{Bh}}^6+{\mathrm{Ch}}^8+{\mathrm{Dh}}^{10}+{\mathrm{Eh}}^{12}$

In formula: Z is aspheric surface along optical axis direction when the position highly for h, apart from the distance rise on aspheric surface summit.

C=1/r, r represent the radius-of-curvature of minute surface, and k is circular cone coefficient conic, and A, B, C, D, E are high order aspheric surface coefficient, and the e in coefficient represents scientific notation, as e-05 represents 10 ^-5, F=0.9mm, FNO=2.0,2 ω=200 °, TTL=16.97mm.

Following table is the related parameter values of lens, and the minute surface beating " * " number is aspheric surface.

Table 1

Face sequence number	Radius-of-curvature r	Center thickness d	Half clear aperture	Refractive index Nd	Abbe constant Vd
						1	12.95	0.8	6.53	1.7725	49.6
2	3.404	2.81	3.32
						*3	33.169	1.02	3.32	1.5120	56.3
*4	1.294	1.75	2.31
						5	7.631	2.02	2.32	1.8467	23.8
6	-7.631	1.8	2.14
						7	infinity	0.15	0.76
*8	8.556	1.77	0.88	1.5346	56.1

*9	-0.687	0.65	1.13	1.5825	30.1
						*10	-9.877	0.1	1.58
*11	3.854	1.61	1.85	1.5120	56.3
						*12	-2.431	0.2	1.91
13	infinity	0.3	1.91	1.5168	64.2
						14	infinity	1.99	1.91
IMA	infinity

That following table is listed is asphericity coefficient K, A, B, C, D, E

Table 2

Face sequence number	K	A	B	C	D	E
							3	79.99021	-0.0042659546	9.4631562e-005	-3.0200331e-006	-3.7003845e-008	-2.999142e-009
4	-1.058149	-0.0032511133	-0.001657005	0.00015082279	-1.965371e-006	4.9503562e-008
							8	3.031043	-0.0014875755	0.0035086339	0.00017211948	0.0024831484	-0.0087874694
9	-1.269367	0.0079119604	-0.20265194	0.091143269	0.023102888	0.00070986224
							10	22.10825	-0.020130878	0.0088589345	-0.00085243241	6.8934527e-006	3.4289817e-005
11	-19.01586	-0.0025299003	0.0038368061	-0.00041239933	3.2806525e-005	-3.3669318e-007
							12	-4.836767	-0.013623879	0.004967567	-0.00033398864	2.2741961e-005	-9.271765e-007

According to above-mentioned case study on implementation data, calculate the numerical value of condition formula involved in claims as table 3 and table 4:

Table 3

Table 4

Embodiments of the invention 2 are as shown in Fig. 5 to Fig. 8, described camera lens comprise successively from the object side to the image side there is negative power front lens group, diaphragm, there is the rear lens group of positive light coke, described front lens group comprises the first lens L1, the second lens L2, the 3rd lens L3 successively from object space side, described rear lens group comprises the 4th lens L4, the 5th lens L5, the 6th lens L6 successively from object space side.

As shown in Figure 5, described second lens all have employed non-spherical lens to the 6th lens.This optical lens is followed successively by the first lens L1, the second lens L2, the 3rd lens L3, diaphragm r7, the 4th lens L4, the 5th lens L5, the 6th lens L6, color filter GF, imaging surface IMA by thing side to image side.

First lens L1 is the diverging meniscus lens with negative focal power, the glass lens element of to be two sides be all sphere; Second lens L2 is the biconcave lens with negative focal power, be two sides is all aspheric plastic lens elements; 3rd lens L3 is the biconvex lens with positive focal power, be two sides is all aspheric plastic lens elements; 4th lens L4 is the double convex glass lens with positive focal power, and the 5th lens L5 is the negative bent moon glass lens with negative focal power, and L4 and L5 is combined into a balsaming lens; 6th lens L6 is the biconvex lens with positive focal power, be two sides is all aspheric plastic lens elements.

Fig. 6 to Fig. 8 is the optical performance curve figure corresponding to embodiment 2, and wherein Fig. 6 is chromatic curve figure (also can be spherical aberration curve map), by commonly use F, d, C tri-the wavelength of coloured light represent, unit is mm.Fig. 7 is astigmatism curve map, by commonly use F, d, C tri-the wavelength of coloured light represent, unit is mm.Fig. 8 is distortion curve figure, represents the distortion sizes values in different field angle situation, and unit is %.

In the present embodiment, the whole focal length value of this optics wide-angle lens is F, f-number is FNO, field angle is 2 ω, camera lens overall length TTL, and by object space side, by each minute surface number consecutively, the minute surface of the first lens L1 is r1, r2, and the minute surface of the second lens L2 is r3, r4, the minute surface of the 3rd lens L3 is r5, r6, diaphragm face is r7, and the minute surface of the 4th lens L4 and the 5th lens L5 is r8, r9, r10, and the minute surface of the 6th lens L6 is r11, r12, the minute surface of color filter GF is r13, r14, and the formula of aspherical mirror is:

$Z\left(h\right)=\frac{{\mathrm{ch}}^2}{1+\sqrt{1-(1+k)c^2{h}^2}}+{\mathrm{Ah}}^4+{\mathrm{Bh}}^6+{\mathrm{Ch}}^8+{\mathrm{Dh}}^{10}+{\mathrm{Eh}}^{12}$

In formula: Z is aspheric surface along optical axis direction when the position highly for h, apart from the distance rise on aspheric surface summit.

C=1/r, r represent the radius-of-curvature of minute surface, and k is circular cone coefficient conic, and A, B, C, D, E are high order aspheric surface coefficient, and the e in coefficient represents scientific notation, as e-05 represents 10 ^-5.

F=0.90mm，FNO=2.0，2ω=187°，TTL=17.02mm

Following table is the correlation parameter of lens, and the minute surface beating " * " number is aspheric surface

Table 5

Face sequence number

Radius-of-curvature r

Center thickness d

Half clear aperture

Refractive index Nd

Abbe constant Vd

1	13.1	0.8	6.24	1.7725	49.6
						2	3.427	2.67	3.30
*3	32.926	0.98	3.39	1.5120	56.3
						*4	1.299	1.74	2.31
*5	5.944	2.0	2.31	1.6355	23.8
						*6	-5.964	1.89	2.14
7	infinity	0.15	0.76
						*8	8.464	1.83	0.87	1.5346	56.1
*9	-0.693	0.65	1.16	1.5825	30.1
						*10	-9.813	0.1	1.55
*11	3.821	1.68	1.77	1.5120	56.3
						*12	-2.432	0.2	1.84
13	infinity	0.3	1.82	1.5168	64.2
						14	infinity	2.0	1.82
IMA	infinity

That following table is listed is asphericity coefficient K, A, B, C, D, E:

Table 6

Face sequence number	K	A	B	C	D	E
							3	80.58686	-0.0042504692	9.207951e-005	-3.031417e-006	-3.3073693e-008	-1.6766032e-009
4	-1.055555	-0.0032133829	-0.0016403787	0.00015137651	-2.3179658e-006	-8.5946605e-009
							5	-0.08022798	-4.8906947e-005	-1.4895662e-005	-2.2704909e-006	-2.6128756e-007	-2.7212036e-008
6	-0.1028616	6.7599093e-005	1.58338e-005	2.1286227e-006	3.0569114e-007	1.694758e-007
							8	3.732483	-0.0013300724	0.003242239	-0.0015030752	0.00040620602	-0.012090322
9	-1.286186	0.012699311	-0.1965926	0.098207211	0.030681026	2.8950911e-005
							10	22.02222	-0.020117535	0.0088747261	-0.00085252398	1.1138494e-005	2.9990352e-005
11	-19.13132	-0.0025779759	0.0038205694	-0.00041333781	3.4110945e-005	-7.5965892e-007
							12	-4.846718	-0.013541154	0.0050000524	-0.00032401493	2.4973762e-005	-1.0894172e-006

According to above-mentioned case study on implementation data, calculate the numerical value of condition formula involved in claims as table 7 and table 8:

Table 7

Table 8

Wide-angle lens provided by the invention, can realize cost low, lightweight, distort little, size is little, high pass optical property and meet high definition require wide-angle lens, simultaneously because have employed more plastic aspheric lens, lighter weight and lower cost can be kept.

Claims (9)

1. a wide-angle lens, it is characterized in that: comprise the front lens group with negative power from the object side to the image side successively, diaphragm, there is the rear lens group of positive light coke, described front lens group comprises the first lens successively from object space side, second lens, 3rd lens, described first lens are convex diverging meniscus lenses to object space, described second lens are the lens of negative bent moon or concave-concave, described 3rd lens are the positive power lens of biconvex, described rear lens group comprises the 4th lens successively from object space side, 5th lens, 6th lens, 4th lens and the 5th lens form a balsaming lens, described 4th lens have positive light coke, described 5th lens have negative power, described 6th lens are the lens of the positive light coke of biconvex, wherein the second lens are in the 6th lens, at least comprising four lens is non-spherical lenses, described second lens and rear lens group meet condition formula below:

-after 1.0 >=F/F2 >=-1.5

Wherein F2 represents the focal length value of the second lens, represents the focal length value of rear lens group after F.

2. wide-angle lens according to claim 1, is characterized in that: described camera lens meets following formula:

220°≥FOV≥130°

Wherein, FOV represents total field angle of described camera lens.

3. wide-angle lens according to claim 1, is characterized in that: described first lens meet relational expression

Nd≥1.65，Vd≥45

Wherein Nd is refractive index, and Vd is Abbe constant.

4. wide-angle lens according to claim 1, is characterized in that: described 3rd lens meet condition formula below:

Nd≥1.55，Vd≤31

Wherein Nd is refractive index, and Vd is Abbe constant.

5. wide-angle lens according to claim 1, is characterized in that: described camera lens meets condition formula below

TTL/EFL≤20

Wherein TTL is the distance of described camera lens first lens object space side outermost point to imaging surface, and EFL is total focal length value of described wide-angle lens.

6. wide-angle lens according to claim 1, is characterized in that: maximum clear aperture and corresponding imaging image height, the field angle of described first lens meet following condition formula:

(d/h)/FOV≤0.025

Wherein FOV represents the maximum field of view angle of wide-angle lens, and d represents the maximum clear aperture of the first lens corresponding to maximum field of view angle towards object space convex surface, and h represents the imaging image height corresponding to maximum field of view angle.

7. wide-angle lens according to claim 1, is characterized in that: described 4th lens and the 5th lens adopt glue to carry out bonding joint formation lens subassembly, and composition surface convex surface facing image side.

8. wide-angle lens according to claim 1, is characterized in that: described 4th lens and the 5th lens adopt plastic material, and composition surface meets following condition formula:

θ≤60°，|R|≤Φ/2

Wherein θ is the tangent line of any point on composition surface and the angle of optical axis, and R is the center curvature radius on composition surface, and Φ is the light effective aperture on composition surface.

9. wide-angle lens according to claim 1, is characterized in that: described camera lens meets condition formula below:

BFL/EFL≥2.0

Wherein BFL is the distance of the 6th lens image side outermost point to imaging surface of described wide-angle lens, and EFL is the focal length value of described wide-angle lens.