CN100410713C - Single focus lens - Google Patents

Abstract

The present invention relates to a single-focus lens which has the advantage of wide visual angle. The present invention comprises a first optical component with weak diopter, a second optical component with positive diopter, a third optical component with negative diopter and a fourth and a fifth optical components with positive diopter from an object end to an imaging end in sequence, and an image sensing unit is arranged on the imaging end. The single-focus lens satisfies the following conditions: 0< |f23/f1|< 0.12, wherein f23 is the synthetic focal length of the second and the third optical components, and f1 is the focal length of the first optical component.

Description

Single-focus lens

Technical field

The present invention relates to a kind of single-focus lens, particularly about a kind of single-focus lens that can be applicable to hand-held photographic attachment.

Background technology

The pixel of miniaturization and increase image sensing unit makes to the requirement of photographic lens more and more stricter.Simultaneously, low-cost video optics system applies product with wide viewing angle is more and more wide, for example monitor, on-vehicle lens and introscope.Japan publication spy opens clear 61-035, has disclosed a kind of introscope head of wide viewing angle No. 414, and this introscope head has four optical modules and has meniscus lens in contiguous imaging end.

Yet the spy opens clear 61-035, though the introscope head that discloses for No. 414 can be revised the distortion aberration, therefore all light vertical incidence CCD from this camera lens of thing end incident can can't be produced shade.

Japan publication spy opens flat 01-218, has disclosed a kind of method of improving above-mentioned shortcoming No. 286.Between object lens and CCD, insert a field lens, make light to impinge perpendicularly on the CCD.Yet this design but makes whole optical system become comparatively complicated.

Japan publication spy opens flat 05-107, has disclosed for No. 470 a kind ofly to object optical system, but still can't solve the problem that produces shade.

Summary of the invention

The object of the present invention is to provide a kind of single-focus lens, the image sensing unit that it has wide viewing angle and is applicable to high pixel.

For achieving the above object, single-focus lens of the present invention comprises the 4th optical module of the 3rd optical module of second optical module of first optical module of weak refractive index, positive refractive index, negative refractive index, positive refractive index and the 5th optical module of positive refractive index successively from the thing end to the imaging end; This single-focus lens meets the following conditions:

$0<\left|\frac{f_{23}}{f_1}\right|<0.12$

Wherein, f ₂₃Be the synthetic focal length of second, third optical module, f ₁It is the focal length of first optical module.

Single-focus lens of the present invention further meets the following conditions:

$0.1<\frac{f_2}{f_{45}}\&times;F_{\mathrm{NO}}<0.4$

Wherein, f ₂Be the focal length of second optical module, f ₄₅Be the synthetic focal length of the 4th, the 5th optical module, F _NONumerical aperture for single-focus lens.

First optical module of single-focus lens of the present invention is the meniscus lens, and its surface towards the thing end is a concave surface.Preferably, first optical module is to make with plastics.

Second optical module of single-focus lens of the present invention is a biconvex lens, and the 3rd optical module is a biconcave lens.Preferably, second, third, the 4th and the 5th optical module all makes with plastics.

First optical module of the present invention can be eliminated longitudinal aberration, distortion aberration, curvature of field aberration and multiplying power chromatic aberation.The 3rd optical module may command imaging height.The the 4th and the 5th optical module can be assisted and be eliminated longitudinal aberration, distortion aberration and curvature of field aberration, and the angle of control chief ray incident imaging surface.

As mentioned above, compared with prior art, the present invention has preferable optical imagery effect.Because first optical module is a concave surface towards the surface of thing end, can will inject in this single-focus lens with bigger incident angle away from the outer light of optical axis effectively, thus the advantage of acquisition wide viewing angle.In addition, single-focus lens of the present invention can effectively reduce the manufacturing cost of this camera lens by using glass lens.

The present invention is further illustrated below in conjunction with accompanying drawing and embodiment.

Description of drawings

Fig. 1 is the optical module arrangement plan of the single-focus lens of first embodiment of the invention;

Fig. 2 is the longitudinal aberration of the single-focus lens of first embodiment of the invention;

Fig. 3 is the multiplying power chromatic aberation of the single-focus lens of first embodiment of the invention;

Fig. 4 is the curvature of field of the single-focus lens of first embodiment of the invention;

Fig. 5 is the distortion aberration of the single-focus lens of first embodiment of the invention;

Fig. 6 is the optical module arrangement plan of the single-focus lens of second embodiment of the invention;

Fig. 7 is the longitudinal aberration of the single-focus lens of second embodiment of the invention;

Fig. 8 is the multiplying power chromatic aberation of the single-focus lens of second embodiment of the invention;

Fig. 9 is the curvature of field of the single-focus lens of second embodiment of the invention;

Figure 10 is the distortion aberration of the single-focus lens of second embodiment of the invention;

Figure 11 is the optical module arrangement plan of the single-focus lens of third embodiment of the invention;

Figure 12 is the longitudinal aberration of the single-focus lens of third embodiment of the invention;

Figure 13 is the multiplying power chromatic aberation of the single-focus lens of third embodiment of the invention;

Figure 14 is the curvature of field of the single-focus lens of third embodiment of the invention;

Figure 15 is the distortion aberration of the single-focus lens of third embodiment of the invention;

Figure 16 is the index path of single-focus lens of the present invention.

Embodiment

Single-focus lens of the present invention is a kind of single-focus lens with wide viewing angle advantage, can be applicable to camera cell phone, PDA etc.This single-focus lens comprises the 3rd optical module of second optical module of first optical module with weak refractive index, positive refractive index, negative refractive index, the 4th optical module of positive refractive index and the 5th optical module of positive refractive index successively from the thing end to the imaging end.This single-focus lens meet the following conditions (1):

$0<\left|\frac{f_{23}}{f_1}\right|<0.12......\left(1\right)$

Wherein, f ₂₃Be the synthetic focal length of the second and the 3rd optical module, f ₁It is the focal length of first optical module.

Preferably, this single-focus lens further meet the following conditions (2):

$0.1<\frac{f_2}{f_{45}}\&times;F_{\mathrm{NO}}<0.4......\left(2\right)$

Wherein, f ₂Be the focal length of second optical module, f ₄₅Be the synthetic focal length of the 4th, the 5th optical module, F _NONumerical aperture for single-focus lens.

In the single-focus lens of the present invention, first optical module is the meniscus lens, and its surface towards the thing end is a concave surface; First optical module has weak refractive index, mainly in order to eliminate longitudinal aberration, distortion aberration, curvature of field aberration and multiplying power chromatic aberation.

Second optical module is a biconvex lens, and before aperture diaphragm was arranged on second optical module, it became the main refractive index of single-focus lens of the present invention.The 3rd optical module is a biconcave lens, mainly act as to be adjusted to the image height degree; When the past more negative direction of the negative refractive index of the 3rd optical module increased, imaging was big highly more, and when the past more positive dirction of the negative refractive index of the 3rd optical module increased, imaging was highly more little.

The 4th optical module and the 5th optical module are positive refractive index lens, and all have non-spherical surface, and its major function is eliminated longitudinal aberration, distortion aberration and curvature of field aberration for auxiliary first optical module, and adjusts the incident angle of chief ray incident imaging surface.

In the present invention, when going up in limited time of greater than condition (1), first optical module can't be revised longitudinal aberration, distortion aberration, curvature of field aberration and multiplying power chromatic aberation.

In the present invention, when the focal distance f of second optical module ₂When excessive, the upper limit that will greater than condition (2) makes that total optical length (totaltrack) of single-focus lens of the present invention is long; Synthetic focal distance f when the 4th, the 5th optical module ₄₅When excessive, lower limit that will less-than condition (2) makes that back Jiao (backfocal length) of single-focus lens of the present invention is long.

Because first optical module is a concave surface towards the surface of thing end, so can will inject in this single-focus lens with bigger incident angle away from the outer light of optical axis effectively, thus the advantage of acquisition wide viewing angle.

Relevant detailed description of the present invention and technology contents, existing as follows with regard to accompanying drawings:

＜detailed description of the invention one 〉

Fig. 1 is first embodiment of single-focus lens of the present invention.This single-focus lens comprises the 3rd lens 30 of second lens 20 of first lens 10 of weak refractive index, positive refractive index, negative refractive index, the 4th lens 40 of positive refractive index and the 5th lens 50 of positive refractive index successively from the thing end to the imaging end.The focal length F=7.92mm of system of this single-focus lens, numerical aperture Fno.=3.2, and full visual angle (Field of View) is 60 degree.

First lens 10 are the meniscus lens, and its surface towards the thing end is convex surface for concave surface towards the surface of imaging end.The refractive index of first lens 10 just can be, and also can be negative; It is made with plastics, and at least one surface is an aspheric surface.Second lens 20 are the biconvex positive lens, and its at least one surface is an aspheric surface and made of plastic.Aperture diaphragm ST is between first lens 10 and second lens 20, and contiguous second lens 20 are provided with; Therefore, depart from optical axis and be incident to second lens 20 by aperture diaphragm ST with the angle that the light of wide-angle incident first lens 10 can be less.In first embodiment, the focal length of first lens 10 is f ₁=1745.9mm, the focal length of second lens 20 are f ₂=3.641mm.

The 3rd lens 30 are double-concave negative lens, and its at least one surface is an aspheric surface and made of plastic.In first embodiment, the synthetic focal length of second lens 20 and the 3rd lens 30 is f ₂₃=12.845mm.

The 4th lens 40 are the meniscus positive lens, and its concave surface is an aspheric surface towards thing end and at least one surface.The 5th lens 50 are positive lens, and at least one surface is an aspheric surface.The 4th lens 40 and the 5th lens 50 are all made of plastic, and its synthetic focal length is f ₄₅=12.85mm.

In first embodiment of the invention, the parameters of first lens 10, second lens 20, the 3rd lens 30, the 4th lens 40 and the 5th lens 50 of single-focus lens is listed in the table 1 successively:

In addition, the aspheric surface correlation values of first embodiment of the invention is listed in table 2 successively:

These coefficients satisfy following aspheric surface formula:

$z=\frac{{\mathrm{ch}}^2}{1+{[1-(k+1)c^2{h}^2]}^{\frac{1}{2}}}+{\mathrm{Ah}}^4+{\mathrm{Bh}}^6+{\mathrm{Ch}}^8+{\mathrm{<figure-callout\; id="10"\; label="Dh"\; filenames="C20061000447700231.png,C20061000447700241.png"\; state="\{\{state\}\}">Dh</figure-callout>}}^{10}+{\mathrm{Eh}}^{12}.$

In first embodiment of the invention,

$\left|\frac{f_{23}}{f_1}\right|=0.00736$

$\frac{f_2}{f_{45}}\&times;F_{\mathrm{NO}}=0.283$

Therefore, every numerical value of single-focus lens of the present invention all eligible (1) and (2).The imaging end of single-focus lens of the present invention is provided with an image sensing unit 60, for example CCD or CMOS; In addition, also can optical filter (not shown) be set between single-focus lens and imaging end, with the filtering infrared light.

Fig. 2 shows the longitudinal aberration (longitudinalaberration) of the single-focus lens of first embodiment of the invention.According to shown in Figure 2, the longitudinal aberration of this single-focus lens in image height 1Y scope all is positioned at the 0.025mm scope.

Fig. 3 shows the multiplying power chromatic aberation (lateral coloraberration) of the single-focus lens of first embodiment of the invention.According to shown in Figure 3, two border wavelength (0.486nm and 0.656nm) all are positioned at 1 mu m range with respect to the multiplying power chromatic aberation of centre wavelength (0.588nm) in image height 1Y scope.

Fig. 4 shows the curvature of field (field curvature) of the single-focus lens of first embodiment of the invention.According to shown in Figure 4, the sagittal beam of this single-focus lens (sagittal beam) all is positioned at the 0.04mm scope with the degree that tangential pencil of rays (tangential beam) separates in maximum image field height 1Y scope, the astigmatic image error that therefore demonstrates this single-focus lens simultaneously is minimum.

Fig. 5 shows the distortion aberration (distortion) of the single-focus lens of first embodiment of the invention.According to shown in Figure 5, the distortion aberration of this single-focus lens in image height 1Y scope is greater than-1%.

＜detailed description of the invention two 〉

Fig. 6 is second embodiment of single-focus lens of the present invention.This single-focus lens comprises the 3rd lens 30 of second lens 20 of first lens 10 of weak refractive index, positive refractive index, negative refractive index, the 4th lens 40 of positive refractive index and the 5th lens 50 of positive refractive index successively from the thing end to the imaging end.The focal length F=8.68mm of system of this single-focus lens, numerical aperture Fno.=3.2, and full visual angle (Field of View) is 55.4 degree.

First lens 10 are the meniscus lens, and its surface towards the thing end is convex surface for concave surface towards the surface of imaging end.The refractive index of first lens 10 just can be, and also can be negative; It is made with plastics, and at least one surface is an aspheric surface.Second lens 20 are the biconvex positive lens, and its at least one surface is an aspheric surface and made of plastic.Aperture diaphragm ST is between first lens 10 and second lens 20, and contiguous second lens 20 are provided with; Therefore, depart from optical axis and be incident to second lens 20 by aperture diaphragm ST with the angle that the light of wide-angle incident first lens 10 can be less.In a second embodiment, the focal length of first lens 10 is f1=76782mm, and the focal length of second lens 20 is f2=3.612mm.

The 3rd lens 30 are double-concave negative lens, and its at least one surface is an aspheric surface and made of plastic.In a second embodiment, the synthetic focal length of second lens 20 and the 3rd lens 30 is f23=12.265mm.

The 4th lens 40 are the meniscus positive lens, and its concave surface is an aspheric surface towards thing end and at least one surface.The 5th lens 50 are positive lens, and at least one surface is an aspheric surface.The 4th lens 40 and the 5th lens 50 are all made of plastic, and its synthetic focal length is f45=20.041mm.

In second embodiment of the invention, the parameters of first lens 10, second lens 20, the 3rd lens 30, the 4th lens 40 and the 5th lens 50 of single-focus lens is listed in the table 3 successively:

In addition, the aspheric surface correlation values of second embodiment of the invention is listed in table 4 successively:

These coefficients satisfy following aspheric surface formula:

$z=\frac{{\mathrm{ch}}^2}{1+{[1-(k+1)c^2{h}^2]}^{\frac{1}{2}}}+{\mathrm{Ah}}^4+{\mathrm{Bh}}^6+{\mathrm{Ch}}^8+{\mathrm{<figure-callout\; id="10"\; label="Dh"\; filenames="C20061000447700231.png,C20061000447700241.png"\; state="\{\{state\}\}">Dh</figure-callout>}}^{10}+{\mathrm{Eh}}^{12}+{\mathrm{Fh}}^{14}.$

In second embodiment of the invention,

$\left|\frac{f_{23}}{f_1}\right|=0.00016$

$\frac{f_2}{f_{45}}\&times;F_{\mathrm{NO}}=0.18$

Therefore, every numerical value of single-focus lens of the present invention all eligible (1) and (2).The imaging end of single-focus lens of the present invention is provided with an image sensing unit 60, for example CCD or CMOS; In addition, also can optical filter (not shown) be set between single-focus lens and imaging end, with the filtering infrared light.

Fig. 7 shows the longitudinal aberration (longitudinal aberration) of the single-focus lens of second embodiment of the invention.According to shown in Figure 7, this single-focus lens all is positioned at the 0.04mm scope at the longitudinal aberration of image height 1Y scope.

Fig. 8 shows the multiplying power chromatic aberation (lateralcolor aberration) of the single-focus lens of second embodiment of the invention.According to shown in Figure 8, two border wavelength (0.486nm and 0.656nm) all are positioned at 1 mu m range with respect to the multiplying power chromatic aberation of centre wavelength (0.588nm) in image height 1Y scope.

Fig. 9 shows the curvature of field (fieldcurvature) of the single-focus lens of second embodiment of the invention.According to shown in Figure 9, the sagittal beam of this single-focus lens (sagittal beam) all is positioned at the 0.04mm scope with the degree that tangential pencil of rays (tangential beam) separates in maximum image field height 1Y scope, the astigmatic image error that therefore also demonstrates this single-focus lens simultaneously is minimum.

Figure 10 shows the distortion aberration (distortion) of the single-focus lens of second embodiment of the invention.According to shown in Figure 10, the distortion aberration of this single-focus lens in image height 1Y scope is greater than-4%.

＜detailed description of the invention three 〉

Figure 11 is the 3rd embodiment of single-focus lens of the present invention.This single-focus lens comprises the 3rd lens 30 of second lens 20 of first lens 10 of weak refractive index, positive refractive index, negative refractive index, the 4th lens 40 of positive refractive index and the 5th lens 50 of positive refractive index successively from the thing end to the imaging end.The focal length F=8.285mm of system of this single-focus lens, numerical aperture Fno.=3.2, and full visual angle (Field of View) is 57.1 degree.

First lens 10 are the meniscus lens, and its surface towards the thing end is convex surface for concave surface towards the surface of imaging end.The refractive index of first lens 10 just can be, and also can be negative; It is made with plastics, and at least one surface is an aspheric surface.Second lens 20 are the biconvex positive lens, and at least one surface is an aspheric surface and made of plastic.Aperture diaphragm ST is between first lens 10 and second lens 20, and contiguous second lens 20 are provided with; Therefore, depart from optical axis and be incident to second lens 20 by aperture diaphragm ST with the angle that the light of wide-angle incident first lens 10 can be less.In the 3rd embodiment, the focal length of first lens 10 is f ₁=-315.03mm, the focal length of second lens 20 are f ₂=3.614mm.

The 3rd lens 30 are double-concave negative lens, and at least one surface is an aspheric surface and made of plastic.In the 3rd embodiment, the synthetic focal length of second lens 20 and the 3rd lens 30 is f ₂₃=11.674mm.

The 4th lens 40 are the meniscus positive lens, and its concave surface is an aspheric surface towards thing end and at least one surface.The 5th lens 50 are positive lens, and at least one surface is an aspheric surface.The 4th lens 40 and the 5th lens 50 are all made of plastic, and its synthetic focal length is f ₄₅=17.124mm.

In third embodiment of the invention, the parameters of first lens 10, second lens 20, the 3rd lens 30, the 4th lens 40 and the 5th lens 50 of single-focus lens is listed in the table 5 successively:

In addition, the aspheric surface correlation values of third embodiment of the invention is listed in table 6 successively:

These coefficients satisfy following aspheric surface formula:

$z=\frac{{\mathrm{ch}}^2}{1+{[1-(k+1)c^2{h}^2]}^{\frac{1}{2}}}+{\mathrm{Ah}}^4+{\mathrm{Bh}}^6+{\mathrm{Ch}}^8+{\mathrm{<figure-callout\; id="10"\; label="Dh"\; filenames="C20061000447700231.png,C20061000447700241.png"\; state="\{\{state\}\}">Dh</figure-callout>}}^{10}+{\mathrm{Eh}}^{12}+{\mathrm{Fh}}^{14}.$

In third embodiment of the invention,

$\left|\frac{f_{23}}{f_1}\right|=0.037$

$\frac{f_2}{f_{45}}\&times;F_{\mathrm{NO}}=0.21$

Therefore, every numerical value of single-focus lens of the present invention all eligible (1) and (2).The imaging end of this single-focus lens is provided with an image sensing unit 60, for example CCD or CMOS; In addition, also can optical filter (not shown) be set between single-focus lens and imaging end, with the filtering infrared light.

Figure 12 shows the longitudinal aberration (longitudinal aberration) of the single-focus lens of third embodiment of the invention.According to shown in Figure 12, the longitudinal aberration of this single-focus lens in image height 1Y scope all is positioned at the 0.02mm scope.

Figure 13 shows the multiplying power chromatic aberation (lateral color aberration) of the single-focus lens of third embodiment of the invention.According to shown in Figure 13, two border wavelength (0.486nm and 0.656nm) all are positioned at 1 mu m range with respect to the multiplying power chromatic aberation of centre wavelength (0.588nm) in image height 1Y scope.

Figure 14 shows the curvature of field (fieldcurvature) of the single-focus lens of third embodiment of the invention.According to shown in Figure 14, the sagittal beam of this single-focus lens (sagittal beam) all is positioned at the 0.1mm scope with the degree that tangential pencil of rays (tangential beam) separates in maximum image field height 1Y scope, the astigmatic image error that therefore also demonstrates this single-focus lens simultaneously is minimum.

Figure 15 shows the distortion aberration (distortion) of the single-focus lens of third embodiment of the invention.According to shown in Figure 15, the distortion aberration of this single-focus lens in image height 1Y scope is greater than-3%.

Figure 16 shows the index path of the single-focus lens of third embodiment of the invention.According to shown in Figure 16, this single-focus lens is in 1Y image height scope, and the maximum incident angle of light incident imaging surface is 16.5 degree, satisfies the incident angle scope (in 20 degree) that general CMOS and CCD require.In addition, emergent pupil (exit pupil) position is between the 3rd lens and the 4th lens.

In sum, the invention provides a kind of single-focus lens, it has better optics Imaging effect. Because the first optics assembly is concave surface towards the surface of thing end, can be effectively with Inject in this single-focus lens with bigger incidence angle away from the light that optical axis is outer, thereby obtain The advantage at wide visual angle. The aperture diaphragm of this camera lens between first lens and second lens and The contiguous second lens setting is so that the exit pupil position of this camera lens is positioned at the 3rd lens and the 4th saturating Between the mirror. In addition, single-focus lens of the present invention is by using glass lens effectively to reduce this The manufacturing cost of camera lens.

Claims (6)

1. a single-focus lens comprises first optical module from the thing end successively to the imaging end, second optical module of positive refractive index, the 3rd optical module of negative refractive index, the 4th optical module of positive refractive index, and the 5th optical module of positive refractive index; It is characterized in that: first optical module is the meniscus lens of weak refractive index, and its surface towards the thing end is a concave surface, is convex surface towards the surface of imaging end; Second optical module is the biconvex positive lens; The 3rd optical module is a double-concave negative lens; The 4th optical module is the meniscus positive lens, and its concave surface is towards the thing end; And this single-focus lens meets the following conditions:

$0<\left|\frac{f_{23}}{f_1}\right|<0.12$

Wherein, f ₂₃Be the synthetic focal length of second, third optical module, f ₁It is the focal length of first optical module.

2. single-focus lens as claimed in claim 1 is characterized in that this single-focus lens further meets the following conditions:

$0.1<\frac{f_2}{f_{45}}\&times;F_{\mathrm{NO}}<0.4$

Wherein, f ₂Be the focal length of second optical module, f ₄₅Be the synthetic focal length of the 4th, the 5th optical module, F _NONumerical aperture for single-focus lens.

3. single-focus lens as claimed in claim 2, the aperture diaphragm that it is characterized in that this single-focus lens is between first optical module and second optical module.

4. single-focus lens as claimed in claim 1 is characterized in that this first, second, third, fourth and the 5th optical module all makes with plastics.

5. single-focus lens as claimed in claim 1, at least one surface that it is characterized in that this second optical module is an aspheric surface.

6. single-focus lens as claimed in claim 5, at least one surface that it is characterized in that the 3rd optical module is an aspheric surface.

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