CN100520477C - Imagery picking lens - Google Patents

Abstract

The present invention provides an image picking lens, which comprises four lenses. The four lenses comprise a first lens with positive refraction rate, a second lens with negative refraction rate, a third lens with positive refraction rate and a fourth lens with weak refraction rate from an object end to an imaging end. The first lens, the third lens and the fourth lens are provided with at least an aspheric surface on the surface of the lens. The image picking lens has to satisfy the requirements as follows: 0.1 and lt; or F/f4 or and lt;1. The F is the focal value of the image picking lens and the f4 is the focal value of the fourth lens.

Description

Imagery picking lens

Technical field

The invention relates to a kind of imagery picking lens, particularly be applied to camera head and lightweight a kind of imagery picking lens.

Background technology

In recent years, mobile phone, portable digital assistant (PDA) and mobile computer, the camera lens module that polygamy can be made a video recording fully.This kind camera lens module wants cube little, in light weight mostly, and because image sensing unit in the past, as CCD or CMOS, resolution quite low, therefore known camera lens module has only one piece of eyeglass to two piece eyeglass mostly.

Nowadays, the manufacture of semiconductor development of technology makes the image sensing unit of using for mobile phone, portable digital assistant and mobile computer be promoted to mega pixel gradually; The eyeglass number of camera lens probably can't provide preferable image quality very little.How to use minimum eyeglass quantity to provide high-resolution imaging, the place that has just become the present invention to overcome difficulties.

Summary of the invention

Therefore, purpose of the present invention is promptly providing a kind of imagery picking lens of legerity type, and it uses four pieces of lens to reduce the weight and the length of imagery picking lens; Side by side, can revise various optical aberrations and obtain splendid image.

According to above-mentioned purpose, imagery picking lens of the present invention comprises the 3rd lens of second lens of first lens of positive refractive index, negative refractive index, positive refractive index and the 4th lens of weak refractive index in regular turn from thing end to imaging end.

As previously discussed, first lens of imagery picking lens of the present invention are the meniscus positive lens, and its thing end surfaces protrudes towards the thing end; The 3rd lens also are the meniscus positive lens, and its imaging end surfaces protrudes towards the imaging end; And the thing end surfaces of the 4th lens protrudes towards the imaging end.

As previously discussed, must satisfy this condition in imagery picking lens of the present invention:

$0.1<\left|\frac{F}{f4}\right|<1$

Wherein, F is the focal length value of this imagery picking lens, and f4 is the focal length value of the 4th lens.

As previously discussed, the first of imagery picking lens of the present invention, the 3rd and the 4th lens all have at least one aspheric surface.

As previously discussed, the aperture mirror diaphragm of imagery picking lens of the present invention is between first lens and second lens.

As previously discussed, the thing end surfaces of the 4th lens of the present invention and imaging end surfaces further need satisfy this condition:

$0.05<\left|\frac{R8-R7}{R8+R7}\right|<0.8$

Wherein, R7 is the radius-of-curvature of the thing end surfaces of the 4th lens, and R8 is the radius-of-curvature of the imaging end surfaces of the 4th lens.

As previously discussed, the thing end surfaces of second lens of imagery picking lens of the present invention protrudes towards the imaging end.

The invention has the advantages that, use four pieces of lens, make imagery picking lens of the present invention have length weak point, lightweight advantage.Preferably, first positive lens, second negative lens, the 3rd positive lens and the 4th lens all can use plastic material to make.

Another advantage of the present invention is, is arranged between first and second lens by the aperture mirror diaphragm, makes imagery picking lens have wide viewing angle.

Now, imagery picking lens of the present invention is described in further detail in conjunction with Figure of description.

Description of drawings

Fig. 1 summary shows the position of the imagery picking lens of the embodiment of the invention;

Fig. 2 shows the spherical aberration of the imagery picking lens of the embodiment of the invention;

Fig. 3 shows the curvature of field aberration of the imagery picking lens of the embodiment of the invention;

Fig. 4 shows the distortion aberration of the imagery picking lens of the embodiment of the invention;

Fig. 5 shows the ray aberration of the imagery picking lens of the embodiment of the invention.

Embodiment

Imagery picking lens of the present invention can be applied to image capture unit, is used for object is imaged in image sensing component, as Charged Coupled Device (Charge Coupled Device is called for short CCD) or complementary metal oxide semiconductor assembly (CMOS).This imagery picking lens comprises first lens, second lens with negative refractive index with positive refractive index in regular turn, has the 3rd lens of positive refractive index and has the 4th lens of weak refractive index from thing end to imaging end.Aperture diaphragm is arranged between first lens and second lens.The first, the 3rd and the 4th lens all have at least one aspheric surface.

In the imagery picking lens of the present invention, first lens are a meniscus positive lens, and its thing end surfaces protrudes towards the thing end.Second lens are a negative lens, and its thing end surfaces protrudes towards the imaging end.The 3rd lens are a meniscus positive lens, and it protrudes towards the imaging end as end surfaces.The thing end surfaces of the 4th lens is recessed to the imaging end, and its imaging end surfaces protrudes towards the imaging end.

In the present invention, imagery picking lens must meet the following conditions:

$0.1<\left|\frac{F}{f4}\right|<1\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\left(1\right)$

Wherein, F is the focal length value of imagery picking lens, and f4 is the focal length value of the 4th lens.When the higher limit of | F/f4| greater than condition (1), the total length of imagery picking lens can be long.When the lower limit of | F/f4| less-than condition (1), the distortion aberration of imagery picking lens (distortion aberration) is healed and is become deterioration and reduce image quality.

In addition, the thing end surfaces of the 4th lens of the present invention and imaging end surfaces further need satisfy this condition:

$0.05<\left|\frac{R8-R7}{R8+R7}\right|<0.8\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\&CenterDot;\left(2\right)$

Wherein, R7 is the radius-of-curvature of the thing end surfaces of the 4th lens, and R8 is the radius-of-curvature of the imaging end surfaces of the 4th lens.When

During the higher limit of greater than condition (2), become make the system aberration of imagery picking lens heal to deterioration and reduce image quality.When

During the lower limit of less-than condition (2), will make the 4th lens can't repair the aberration of imagery picking lens.

Consult Fig. 1, the embodiment of imagery picking lens of the present invention, this imagery picking lens comprise the first lens G1, the second lens G2 that bears refractive index, the 3rd lens G3 of positive refractive index and the 4th lens G4 of weak refractive index of positive refractive index in regular turn to imaging end IMA from thing end OBJ; And system's focal length of this imagery picking lens is F=5.30mm, and Fno.=2.86.In addition, aperture diaphragm STO is between the first lens G1 and the second lens G2.

The first lens G1 is a meniscus positive lens, comprises first surface L1 and second surface L2 from thing end OBJ again respectively to imaging end IMA, and the first surface L1 of adjacent near the object end OBJ protrudes towards thing end OBJ.In addition, first surface L1 and second surface L2 are all aspheric surface.

The second lens G2 is a negative lens, and the 3rd Surface L 3 of adjacent near the object end OBJ must be protruded towards imaging end IMA.Consult Fig. 1, in this embodiment, the second lens G2 is a biconcave lens, and the 4th Surface L 4 of contiguous imaging end IMA is protruded towards thing end OBJ.In addition, the 3rd Surface L 3 and the 4th Surface L 4 are all aspheric surface.

The 3rd lens G3 is a meniscus positive lens, comprises the 5th Surface L 5 and the 6th Surface L 6 from thing end OBJ again respectively to imaging end IMA, and the 6th Surface L 6 of contiguous imaging end IMA is protruded towards imaging end IMA.In addition, the 5th Surface L 5 and the 6th Surface L 6 are all aspheric surface.

The 4th lens G4 is meniscus lens, comprises the 7th Surface L 7 and the 8th Surface L 8 from thing end OBJ again respectively to imaging end IMA, and the 8th Surface L 8 of contiguous imaging end IMA is protruded towards imaging end IMA.In addition, the 7th Surface L 7 and the 8th Surface L 8 are all aspheric surface.

In embodiments of the invention, the parameters of the first, second, third and the 4th lens of imagery picking lens is listed in the table 1 in regular turn:

In addition, in the embodiment of the invention, the 5th Surface L 5 of the 3rd Surface L 3 of the first surface L1 of the first lens G1 and second surface L2, the second lens G2 and the 4th Surface L 4, the 3rd lens G3 and the 7th Surface L 7 and the 8th Surface L 8 of the 6th Surface L 6 and the 4th lens G4 are aspheric surface, and its aspheric correlation values is listed in table 2 in regular turn:

According to table 1, can learn the focal distance f 4=-20.963 of the 4th lens G4 of weak refractive index, can get | F/f4|=0.253 and eligible really (1).

According to table 1, can learn the radius of curvature R 7=-0.87mm of the 7th Surface L 7 of the 4th lens G4, the radius of curvature R 8=-1.350mm of the 8th Surface L 8 of the 4th lens G4.With R7 and R8 substitution

Can get $\left|\frac{R8-R7}{R8+R7}\right|=0.216$ And eligible really (2).

Fig. 2 shows the spherical aberration (Spherical aberration) of the imagery picking lens of the embodiment of the invention.In the pupil radius was the scope of 0.9283mm, spherical aberration was less than 0.07mm.

Fig. 3 shows the curvature of field aberration (Field Curvature) of the imagery picking lens of the embodiment of the invention.In the image field height was the scope of 2.9mm, the curvature of field aberration of the light of meridian ellipse and sagittal surface was less than 0.08mm.

Fig. 4 shows the distortion aberration (distortion aberration) of the imagery picking lens of the embodiment of the invention.In the image field height was the scope of 2.9mm, the distortion phase residual quantity of each wavelength light was all less than in 0.15% scope.

Fig. 5 shows the ray aberration (ray aberration claims rayfans again) of the imagery picking lens of the embodiment of the invention.When the image height degree was respectively 0.0mm, 1.8mm, 2.3mm and 2.9mm, the ray aberration of this imagery picking lens was still kept quite smooth.

As known from the above, the imagery picking lens of the embodiment of the invention has splendid image quality; Though all use the lens of plastics ejection formation in first lens, second lens, the 3rd lens and the 4th lens, be not subjected to temperature variation and image quality is worsened.

With reference to figure 1 and table 1, the aperture diaphragm STO of imagery picking lens of the present invention is between the first lens G1 and the second lens G2.

The above, only be specific embodiments of the invention, when not limiting scope of the invention process with this, promptly the simple equivalent of being done according to the present patent application claim and invention description content generally changes and modifies, and all still belongs in the scope that patent of the present invention contains.

Claims (9)

1. an imagery picking lens is characterized in that, comprises in regular turn on optical axis from thing end to imaging end:

First lens are positive refractive index;

Second lens are negative refractive index;

The 3rd lens are a meniscus positive lens, have a thing end surfaces and a picture end surfaces, and it protrude towards the imaging end as end surfaces; And

The 4th lens are weak refractive index, are meniscus lens, have a thing end surfaces and a picture end surfaces, and it protrude towards the imaging end as end surfaces;

Wherein, the aperture mirror diaphragm is arranged between first lens and second lens, and this imagery picking lens meets the following conditions:

$0.1<\left|\frac{F}{f4}\right|<1$

Wherein, F is the focal length value of this imagery picking lens, and f4 is the focal length value of the 4th lens.

2. imagery picking lens as claimed in claim 1 is characterized in that, first lens are a meniscus positive lens, have a thing end surfaces and a picture end surfaces, and its thing end surfaces protrudes towards the thing end.

3. imagery picking lens as claimed in claim 2 is characterized in that, second lens have a thing end surfaces and a picture end surfaces, and its thing end surfaces protrudes towards the imaging end.

4. imagery picking lens as claimed in claim 1 or 2 is characterized in that, this imagery picking lens further satisfies this condition:

$0.05<\left|\frac{R8-R7}{R8+R7}\right|<0.8$

Wherein, R7 is the radius-of-curvature of the thing end surfaces of the 4th lens, and R8 is the radius-of-curvature of the imaging end surfaces of the 4th lens.

5. imagery picking lens as claimed in claim 2 is characterized in that, it is aspheric surface that the first meniscus positive lens has at least one surface.

6. imagery picking lens as claimed in claim 2 is characterized in that, it is aspheric surface that the 3rd meniscus positive lens has at least one surface.

7. imagery picking lens as claimed in claim 2 is characterized in that, it is aspheric surface that the 4th lens have at least one surface.

8. imagery picking lens as claimed in claim 3 is characterized in that it is aspheric surface that second negative lens has at least one surface.

9. imagery picking lens as claimed in claim 6, wherein the first, the 3rd meniscus positive lens is made by plastic material.

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