CN101937123A - Optical lens component - Google Patents

Abstract

The invention relates to an optical element and provides an optical lens component. The optical lens component comprises a lens group, wherein the lens group contains a first lens and a second lens which are coaxial and arranged from the object to the image; the first lens is a meniscus lens with a positive diopter, the second lens is a lens which is formed by a third surface and a fourth surface and has a negative diopter; and the third surface and the fourth surface are M-shaped aspheric surfaces. The lens group satisfies the following conditions: 1.0<L/f<1.35; f1>0, and 0.5<f/f1<1; f2<0, and -0.3<f/f2<0, wherein f represents the effective focal length of the entire optical lens component; L represents the total length of the optical system; f1 represents the effective focal length of the first lens; and f2 represents the effective focal length of the second lens. The optical lens component of the invention only uses two lenses, thus shortening the total length of the lens; and the aberration of the lens component is rectified to obtain better optical property; and the cost is reduced.

Description

A kind of optical lens assembly

Technical field

The present invention relates to optical device, be specifically related to a kind of optical lens assembly.

Background technology

In digital image-forming equipment, the optical imagery camera lens is particularly important assembly, and the picture element of camera lens has directly determined the imaging performance of digital image-forming equipment.Digital product is brought in constant renewal in and is regenerated simultaneously, develops to compact direction day by day, thereby also forces lens design constantly to pursue shorter optics length overall.In the good imaging effect that guarantees camera lens, reduce production costs as much as possible, possess good processability, adapting to industrial large quantities of volume production also all becomes required satisfied important requirement in the lens optical design.

Summary of the invention

Technical matters to be solved by this invention is to overcome the deficiencies in the prior art, provides a kind of and can effectively proofread and correct various aberrations, total length, and volume is little, optical lens assembly with low cost.

Technical scheme provided by the invention: a kind of optical lens assembly, comprise lens combination, described lens combination comprises first lens and second lens coaxial and that be arranged in order from object space to picture side; Described first lens are the meniscus lenses with positive diopter with first surface and second surface, and described second lens are to have the negative dioptric lens of having of the 3rd surface and the 4th surface; Described the 3rd surface is that convex surface, edge are the M type aspheric surface of concave surface for the center, and the 4th surface is a concave surface for the center, and the edge is the M type aspheric surface of convex surface; And described lens combination meets the following conditions:

1.0＜L/f＜1.35；

F1＞0, and 0.5＜f/f1＜1;

F2＜0, and-0.3＜f/f2＜0;

Wherein f is the effective focal length value of whole lens combination; L is the optical system length overall; F1 is the effective focal length value of first lens; F2 is the effective focal length value of second lens.

The invention has the beneficial effects as follows: the lens combination that technical solution of the present invention adopts two lens that satisfy above-mentioned condition of positive and negative diopter combinations to form, realized each aberration, carry out good rectification, shortened the length overall of camera lens simultaneously, and lens assembly of the present invention is easy to processing, helps cost and reduces.

Description of drawings

The optical assembly structure synoptic diagram of Fig. 1 optical lens assembly embodiment one of the present invention;

Optical lens MTF (optical transfer function) figure of Fig. 2 embodiment two;

The optical lens curvature of field synoptic diagram of Fig. 3 embodiment two;

The optical lens distortion synoptic diagram of Fig. 4 embodiment two;

The optical lens MTF figure of Fig. 5 embodiment three;

The optical lens curvature of field synoptic diagram of Fig. 6 embodiment three;

The optical lens distortion synoptic diagram of Fig. 7 embodiment three.

The specific embodiment mode

In order to make purpose of the present invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.

Embodiment one:

As shown in Figure 1, a kind of optical lens assembly that the embodiment of the invention one provides, comprise lens combination, wherein, described lens combination comprises first lens 2 and second lens 3 coaxial and that be arranged in order from object space to picture side, first lens 2 are to have towards the first surface 21 of object space and towards the lens of the curved month type of the second surface 22 of picture side, and second lens 3 have the 3rd surperficial 31 the 4th surface 32 that reaches towards picture side towards object space; Described first surface 21 is concave surface and is aspheric surface for convex surface, second surface 22; The 31 and the 4th surface 32, described the 3rd surface is aspheric surface; Described the 3rd surface is that convex surface, edge are the M type aspheric surface of concave surface for the center, and the 4th surface is a concave surface for the center, and the edge is the M type aspheric surface of convex surface.So the 3rd, the 4th surface all has the point of inflexion; First lens have positive diopter, and second lens have negative diopter.Described lens combination meets the following conditions:

1.0＜L/f＜1.35；

F1＞0, and 0.5＜f/f1＜1;

F2＜0, and-0.3＜f/f2＜0;

Wherein f is the effective focal length value of lens combination; L is the optical system length overall; F1 is the effective focal length value of first lens; F2 is the effective focal length value of second lens.

Described optical lens assembly only adopts two plastic lenss of positive and negative diopter combinations, and four aspheric surface designs have been shortened the length overall of camera lens, and have been easy to processing, help cost and reduce.And the relation between lens assembly length overall and each the lens effective focal length value is limited, further shortened the length overall of camera lens.Described optical lens assembly is well corrected each aberration simultaneously, has obtained optical property preferably.

The material of described first lens 2 and second lens 3 can be that optical glass also can be optical plastic, preferred described first lens of present embodiment and second lens material are optical plastic, to satisfy the requirement of current consumer to the low cost of product, ultra-thin, ultralight.

Further, the optical lens assembly of the embodiment of the invention also comprises fixed aperture 1, be used to control the luminous flux of scioptics group, described fixed aperture 1 can be arranged at the front of first lens 2, promptly be arranged in the object space zone of front of the first surface 21 of first lens 2, also can be arranged on the first surface 21 of first lens 2, preferably, in the present embodiment, fixed aperture 1 is arranged at the front of first lens 2.Fixed aperture 1 is arranged at before first lens 2, can increase the application scenario of optical lens assembly.

Further; described lens combination back promptly also is arranged at intervals with the sheet glass 401 and a cover glass 402 of at least one light transmitting surface plating infrared cut-off light filtering films (IR-cut Coating) in the zone, picture side of second lens, 3 back successively; come from Infrared in the object reflection ray with filtering, improve this lens assembly image quality in the application of digital domain.Preferred described sheet glass material is BK7, and refractive index and chromatic dispersion are respectively n=1.5168, v=64.17.

Described first surface, second surface, the 3rd surface and the 4th surface are aspheric surface, and described aspheric pictograph closes following formula:

$z=\frac{{\mathrm{<figure-callout\; id="2"\; label="cr"\; filenames="H2009101084535E0000012.png,H2009101084535E0000031.png"\; state="\{\{state\}\}">cr</figure-callout>}}^2}{1+\sqrt{1-(1+k)c^2{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="H2009101084535E0000012.png,H2009101084535E0000031.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}+a_1{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="H2009101084535E0000012.png,H2009101084535E0000031.png"\; state="\{\{state\}\}">r</figure-callout>}}^2+a_2{\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="H2009101084535E0000012.png,H2009101084535E0000031.png"\; state="\{\{state\}\}">r</figure-callout>}}^4+a_3{\mathrm{<figure-callout\; id="6"\; label="r"\; filenames="H2009101084535E0000012.png"\; state="\{\{state\}\}">r</figure-callout>}}^6+a_4{\mathrm{<figure-callout\; id="8"\; label="r"\; filenames="H2009101084535E0000031.png"\; state="\{\{state\}\}">r</figure-callout>}}^8+a_5{r}^{10}+a_6{r}^{12}$

Wherein: z is for being starting point with each aspheric surface and optical axes crosspoint, the axial axial value of vertical light, and k is the quadric surface coefficient, c is the minute surface curvature of centre, c=1/R, wherein R is a minute surface curvature of centre radius, r is the minute surface centre-height; a ₁, a ₂, a ₃, a ₄, a ₅, a ₆Be asphericity coefficient.

By above-mentioned aspheric surface formula as can be known, have or not array parameter just can obtain numerous aspheric surface.As long as four aspheric surfaces of four groups of parameter correspondences are formed two lens mutually, satisfy the required condition of said lens group, be lens provided by the present invention.Again by two embodiment, provide two parts of parameters, below so that the technician can more clearly know advantage of the present invention.

Embodiment two:

Second embodiment provided by the present invention, on the basis of embodiment one, the correlation parameter that has further proposed optical lens assembly is as follows:

Lens parameters:

Type	Radius-of-curvature (R)	Quadric surface coefficient (k)	Thickness (dmm)
				First surface	0.3065481	-0.6036636	0.45
Second surface	6.060042	-109.6843	0.21
				The 3rd surface	2.120604	0	0.47
The 4th surface	25.37939	0	0.03
				The optical filter front surface			0.3
The optical filter rear surface			0.03
				The cover glass front surface			0.4
The cover glass rear surface			0.08
				Image planes			0

Asphericity coefficient:

Type	a 1	a 2	a 3	a 4	a 5	a 6
							First surface	0.79557307	-1.7447899	25.720513	-635.18976	-5881.2387	18905.521
Second surface	-0.20089185	-0.085299287	17.918949	-488.87274	-5672.7655	23245.273
							The 3rd surface	-0.18457871	2.9242406	42.620666	-833.78668	6647.5812	-23456.297
The 4th surface	-0.045249709	-0.16482521	1.0245223	0.96976923	-2.9511695	-2.9436238

In the table thickness d for this reason identity distance from next distance, the length overall L=1.97mm of this camera lens, effective focal length value f=1.51mm, the effective focal length value f1=1.522mm of first lens, the effective focal length value f2=-67.88mm of second lens, f/f1=0.99, f/f2=-0.022, f-number FNO.=2.8.

In the present embodiment, preferably, the material of first lens is refractive index＜1.55, the optical material of dispersion values＞50, and wherein preferred plastic material 480R (armorphous polyolefin), refractive index and chromatic dispersion are respectively n1=1.525, v1=56; The material of second lens is refractive index＞1.57, the optical material of dispersion values＜32, and wherein preferred plastic material PC (polycarbonate), refractive index and chromatic dispersion are respectively n2=1.585, v2=29.5.

Fig. 2 is modulation transfer function (ModulationTransfer Function the is called for short MTF) curve map of the optical lens assembly of the embodiment of the invention two, transverse axis representation space frequency among the figure, and unit: line is to every millimeter (lp/mm); The longitudinal axis is represented the numerical value of modulation transfer function (MTF), and the numerical value of described MTF is used for estimating the image quality of camera lens, and span is 0-1, and the image quality of the high more straight more expression camera lens of MTF curve is good more, and is strong more to the reducing power of true picture.As can be seen from Figure 2, the MTF curve of each visual field meridian direction (T) and sagitta of arc direction (S) direction very close to, it shows: this lens assembly is in each visual field, the imaging performance of meridian direction (T) and this both direction of sagitta of arc direction (S) has good consistance, can guarantee that lens assembly can both blur-free imaging on whole imaging surface, and clear, ill-defined situation in the middle of can not occurring.

Fig. 3 and Fig. 4 are respectively the curvature of field and the distortion figure of the optical lens assembly of the embodiment of the invention two, and from Fig. 3 and Fig. 4 as can be seen, the curvature of field of this optical lens assembly is less than 0.10mm, and distortion is less than 2%; Can cooperate the requirement of complementary metal oxide semiconductor (CMOS) (CMOS)/Charge Coupled Device (CCD) (Charge CoupledDevice is called for short CCD) image sensor reception of main flow on the market.

Therefore embodiment provided by the invention can guarantee suitable back focal length on the basis of shortening the camera lens length overall, can also each aberration be that non-point image difference and aberrance are well corrected especially, and obtain desirable optical property.

Embodiment three:

The 3rd embodiment provided by the present invention, on the basis of embodiment one, the correlation parameter that has further proposed optical lens assembly is as follows:

Lens parameters:

Type	Radius-of-curvature (R)	Quadric surface coefficient (k)	Thickness (dmm)
				First surface	?0.286928	?-0.9151723	0.44
Second surface	?6.060042	?-109.6843	0.22
				The 3rd surface	?1.877226	?0	0.45
The 4th surface	5.569566	0	0.03
				The optical filter front surface			0.3
The optical filter rear surface			0.03
				The cover glass front surface			0.4
The cover glass rear surface			0.11
				Image planes			0

Asphericity coefficient:

Type	a 1	a 2	a 3	a 4	a 5	a 6
							First surface	0.92146389	-0.39950241	9.699738	-122.85776	-836.6011	1032.5668
Second surface	-0.20089185	-0.085299287	17.918949	-488.87274	-5672.7655	23245.273
							The 3rd surface	-0.16835492	1.4269877	12.701222	-106.74168	624.42756	-1035.4033
The 4th surface	-0.022070965	-0.27927278	1.2529316	-2.1617147	-6.8661975	8.2112434

In the table thickness d for this reason identity distance from next distance, the length overall L=1.98mm of this camera lens, effective focal length value f=1.52mm, the effective focal length value f1=1.56mm of first lens, the effective focal length value f2=-83.67mm of second lens, f/f1=0.97, f/f2=-0.018, f-number FNO.=2.8.

In the present embodiment, preferably, the material of first lens is refractive index＜1.55, the optical material of dispersion values＞50, and wherein preferred plastic material 480R (armorphous polyolefin), refractive index and chromatic dispersion are respectively n1=1.525, v1=56; The material of second lens is refractive index＞1.57, the optical material of dispersion values＜32, and wherein preferred plastic material PC (polycarbonate), refractive index and chromatic dispersion are respectively n2=1.585, v2=29.5.

Fig. 5 is modulation transfer function (ModulationTransfer Function the is called for short MTF) curve map of the optical lens assembly of the embodiment of the invention three, transverse axis representation space frequency among the figure, and unit: line is to every millimeter (lp/mm); The longitudinal axis is represented the numerical value of modulation transfer function (MTF), and the numerical value of described MTF is used for estimating the image quality of camera lens, and span is 0-1, and the image quality of the high more straight more expression camera lens of MTF curve is good more, and is strong more to the reducing power of true picture.As can be seen from Figure 2, the MTF curve of each visual field meridian direction (T) and sagitta of arc direction (S) direction very close to, it shows: this lens assembly is in each visual field, the imaging performance of meridian direction (T) and this both direction of sagitta of arc direction (S) has good consistance, can guarantee that lens assembly can both blur-free imaging on whole imaging surface, and clear, ill-defined situation in the middle of can not occurring.

Fig. 6 and Fig. 7 are respectively the curvature of field and the distortion figure of the optical lens assembly of the embodiment of the invention three, and as can be seen from Figures 6 and 7, the curvature of field of this optical lens assembly is less than 0.10mm, and distortion is less than 1%; Can cooperate the requirement of complementary metal oxide semiconductor (CMOS) (CMOS)/Charge Coupled Device (CCD) (Charge CoupledDevice is called for short CCD) image sensor reception of main flow on the market.

Therefore embodiment provided by the invention can guarantee suitable back focal length on the basis of shortening the camera lens length overall, can also each aberration be that non-point image difference and aberrance are well corrected especially, and obtain desirable optical property.

The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.

Claims (8)

1. an optical lens assembly comprises lens combination, it is characterized in that: described lens combination comprises first lens and second lens coaxial and that be arranged in order from object space to picture side; Described first lens are the meniscus lenses with positive diopter with first surface and second surface, and described second lens are to have the negative dioptric lens of having of the 3rd surface and the 4th surface; Described the 3rd surface is that convex surface, edge are the M type aspheric surface of concave surface for the center, and the 4th surface is a concave surface for the center, and the edge is the M type aspheric surface of convex surface; And described lens combination meets the following conditions:

1.0＜L/f＜1.35；

F1＞0, and 0.5＜f/f1＜1;

F2＜0, and-0.3＜f/f2＜0;

Wherein f is the effective focal length value of whole lens combination; L is the optical system length overall; F1 is the effective focal length value of first lens; F2 is the effective focal length value of second lens.

2. according to the described optical lens assembly of claim 1, it is characterized in that: the material of described lens combination is optical plastic.

3. according to the described optical lens assembly of claim 2, it is characterized in that: the material of first lens be refractive index less than 1.55, dispersion values is greater than 50 optical plastic; The material of second lens be refractive index greater than 1.57, dispersion values is less than 32 optical plastic.

4. according to the described optical lens assembly of claim 3, it is characterized in that: the material of first lens is armorphous polyolefin, and refractive index is 1.525, dispersion values is 56; The material of second lens is a polycarbonate, and refractive index is 1.585, dispersion values is 29.5.

5. according to the described optical lens assembly of claim 1, it is characterized in that: also comprise fixed aperture, described fixed aperture is positioned at the first lens front.

6. according to the described optical lens assembly of claim 1, it is characterized in that: also comprise optical filter, described optical filter is the sheet glass that at least one light transmitting surface is coated with infrared cut-off light filtering films, and described optical filter is positioned at the back of second lens.

7. optical lens assembly according to claim 6 is characterized in that: described sheet glass is the glass of BK7 material, and refractive index is 1.5168, dispersion values is 64.17.

8. according to each described optical lens assembly of claim 1 to 7, it is characterized in that: the face pictograph on described first surface, second surface, the 3rd surface and the 4th surface closes following formula:

$z=\frac{{\mathrm{cr}}^2}{1+\sqrt{1-(1+k)c^2{r}^2}}+a_1{r}^2+a_2{r}^4+a_3{r}^6+a_4{r}^8+a_5{r}^{10}+a_6{r}^{12}$

Wherein: z is for being starting point with each aspheric surface and optical axes crosspoint, the axial axial value of vertical light, and k is the quadric surface coefficient, c is the minute surface curvature of centre, c=1/R, wherein R is a minute surface curvature of centre radius, r is the minute surface centre-height; a ₁, a ₂, a ₃, a ₄, a ₅, a ₆Be asphericity coefficient.

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