CN201440185U - Minitype three-lens optical pick-up camera with short back focal length - Google Patents

Abstract

The utility model discloses a minitype three-lens optical pick-up camera with short back focal length, which comprises a positively dioptric first lens, an aperture diaphragm, a negatively dioptric second lens and a third lens, which are arranged along the optic axis in sequence from the object to the image. The positively dioptric first lens is a crescent aspheric lens with the convex surface facing the object; the negatively dioptric second lens is a crescent aspheric lens with the convex surface facing the image; the third lens is a negatively dioptric aspheric lens with the center located on the axis; the convex surface of the third lends, along the center of the lens, faces the object while the concave surface faces the object; and the part of the third lens from the center to the edge of the lens has negative diopter, and the part behind the inflection point turns to be positively dioptric. The optical pick-up camera meets the optical condition that bf and TL are respectively the back focal length and the total length of the optical pick-up camera, thus the optical pick-up camera can effectively rectify the optical aberration and can have high resolution, and lengths of the lens and the back focal length can be effectively reduced, thereby miniaturizing the camera, reducing the cost of the camera and improving the application of the pick-up camera.

Description

The burnt small-sized prismatic glasses optical shooting lens in short back

Technical field

The burnt small-sized prismatic glasses optical shooting lens in the relevant a kind of short back of the utility model refers to a kind of at mobile phone or use the optical system of CCD (charge-coupled device (CCD)) or CMOS image sensor such as (complementary metal oxide semiconductor (CMOS)s) and provide a kind of short, short back of total length that is made of prismatic glasses burnt and optical shooting lens cheaply especially.

Background technology

Progress along with science and technology, electronic product constantly develops towards compact and multi-functional direction, and in the electronic product as: digital camera (Digital Still Camera), camera computer (PC camera), network cameras (Network camera), mobile phone (mobile phone) etc. have possessed outside the image-taking device (camera lens), even personal digital assistance devices such as (PDA) also has the demand that adds image-taking device (camera lens); And for easy to carry and meet the demand of hommization, image-taking device not only needs to have good image quality, also need simultaneously smaller volume and lower cost, could effectively promote the application of this image-taking device, especially be applied on the mobile phone, above-mentioned needs or condition are even more important.

And because the material selectivity of traditional sphere abrading glass lens is more, and aberration is comparatively favourable for revising, widely industry is used, but when sphere abrading glass lens were applied in the situation that burnt number (F number) is less and field angle (field angle) is bigger, the correction of aberrations such as spherical aberration and astigmatism was still difficult; And in order to improve the shortcoming of above-mentioned traditional sphere abrading glass lens, present image-taking device is existing to be used aspheric surface plastic cement lens or uses the aspheric surface molded glass lens, to obtain preferable image quality, as U.S.'s patent of invention: US2007/0091457, US 6,515,809, US 7,262,925, US 2007/0195432, US2005/0128334, or as Jap.P. JP 2007-121820, JP2005-352317, JP2004-163786, JP 2007-094113, JP 2005-338234JP 2007-047513, JP 2006-098976 etc., many optical shooting lens structural designs that comprise three-chip type lens (lens elements); Difference place between the structural design of above-mentioned many utility model patents or technical characterictic then are decided by the variation or the combination of following various factors: the shaped design difference of corresponding matching between these three lens in each part patent, be all meniscus (meniscus shape) lens as first, second and third three lens such as grade, or first and second lens are meniscus and the 3rd lens are platycelous (plano-concave shape) or planoconvex (plano-convexshape); And/or the convex surface of corresponding matching/concave direction difference between these three lens in each part patent, can be arranged in thing side/as the convex surface/concave surface of the first/two/third-class three lens as multiple variation combinations such as sides; And/or in each part patent between these three lens the diopter of corresponding matching (refractive power) just/negative different, specially permit No. 3717488 patent etc. as Japan; As from the foregoing, with regard to the design of the optical shooting lens of three lens, its known techniques is in design optical shooting lens technical field, application for various different optical purposes, and produce different variations or combination, because of it uses lens shape, combination, effect or effect difference, promptly can be considered to have novelty (novelty) or progressive (inventive step).

In recent years for be applied to compact camera, product such as the mobile phone of taking pictures, PDA, its sampling image lens requires miniaturization, focal length is short, the aberration adjustment is good, in the three lens sampling image lens design of various miniaturizations, with first lens of positive diopter, negative dioptric second lens, have the point of inflexion and change positive and negative dioptric prismatic glasses (being called M type eyeglass, M-shaped lens), most probable reaches the demand of miniaturization; For different formation methods: at first is positive diopter, second is negative diopter, the 3rd is positive diopter M type eyeglass, as European patent EP 1830210, Japanese patent application publication No. JP2008-139853, JP2006-178328, U.S. Pat 7,397,613, US7,486,328, US7,423,817, US7,468,847, US7,515,358, U.S. Patent Publication No. US2007/0195426, US2007/0217034, US 2007/0229986, US2008/0239510, Taiwan patent TW M343167, Taiwan patent publication No. TW200639432, Chinese patent publication number CN1670560, CN1873460 etc.; At first is positive diopter, second is negative diopter, the 3rd is negative diopter M type eyeglass, as European patent EP 1840618, EP1942363, U.S. Pat 7,460,315, US7,460,314, US7,450,323, US7,511,899, U.S. Patent Publication No. US2007/0229987, US2008/0225401, US2008/0266679, US2008/0225401, US2007/0195426, Jap.P. JP3816093, Japanese patent application publication No. JP2008-276200, JP2008-233222, JP2008-276200, JP2007-010773, WIPO patent WO2007039980, Chinese patent publication number CN1945372 etc.

Yet, be applied on the optical shooting lens, especially be used in small-sized (thin type) device as the sampling image lens of mobile phone, network cameras sampling image lens etc., diameter of lens little (the eyeglass effective radius is little), sampling image lens total length short (the total length of eyeglass), image sensor and eyeglass are the urgent demand of user apart from weak point (short back Jiao) and optical shooting lens with good aberration correction.Prior art uses different lens to form, uses different lens shapes or uses different relative photo mathematic(al) parameters etc. on head it off.But be in easy design and the manufacturing, the utility model proposes the burnt optical shooting lens in short back, especially on second lens design, adopt relative long focal length, can effectively shorten back focal length length, to apply on the small-sized slim mobile phone or optical system.

Summary of the invention

The purpose of this utility model is, solve existing being applied in the sampling image lens technology of small-sized (thin type) device as the sampling image lens of mobile phone, network cameras, use different lens to form, use different lens shapes or use different relative photo mathematic(al) parameters, make the sampling image lens complex structure, the cost technical problems of high.

For achieving the above object, the utility model provides a kind of short back burnt small-sized prismatic glasses optical shooting lens, and it is arranged by thing side (object side) to picture side (image side) along optical axis and comprises in regular turn: first lens of a positive diopter (a first lens of positive refractive power) are that a meniscus non-spherical lens and its convex surface are towards the thing side; One aperture diaphragm (aperture stop); One to have negative dioptric second lens be that a meniscus non-spherical lens and its convex surface are towards the picture side; One the 3rd lens are a negative dioptric non-spherical lens, its lens center is positioned on the optical axis, convex surface is towards the thing side and concave surface is towards the picture side on the lens center, and becomes positive diopter for negative diopter through the point of inflexion (inflection point) to rims of the lens from the lens center; And, be relatively long focal length at second lens for shortening back focal length; And this optical shooting lens further meets the following conditions:

$0.25\≤\frac{\mathrm{bf}}{\mathrm{TL}}\≤0.4---\left(1\right)$

$0.001\≤\frac{\mathrm{\Δ}}{f}\≤0.006---\left(2\right)$

$0.38\≤\frac{H_{-}}{H_t}\≤0.7---\left(3\right)$

$-0.12\&le;\frac{f_1}{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009201568524E00072.png,H2009201568524E00081.png"\; state="\{\{state\}\}">f</figure-callout>}}_2}\&le;-0.01---\left(4\right)$

$0.25\&le;\frac{d_3+{\mathrm{<figure-callout\; id="5"\; label="d"\; filenames="H2009201568524E00011.png,H2009201568524E00041.png"\; state="\{\{state\}\}">d</figure-callout>}}_5+d_7+d_9}{f}\&le;0.5---\left(5\right)$

$0.7\&le;\frac{f_1}{f}\&le;1.2---\left(6\right)$

$-0.2\&le;\frac{R_{21}-R_{22}}{{\mathrm{<figure-callout\; id="21"\; label="R"\; filenames="H2009201568524E00011.png,H2009201568524E00041.png"\; state="\{\{state\}\}">R</figure-callout>}}_{21}+{\mathrm{<figure-callout\; id="22"\; label="R"\; filenames="H2009201568524E00011.png,H2009201568524E00081.png"\; state="\{\{state\}\}">R</figure-callout>}}_{22}}\&le;-0.06---\left(7\right)$

Wherein, f is the effective focal length of this sampling image lens system, bf is the back focal length (backfocal length) of this sampling image lens system, TL is that the first lens thing is surveyed the total length of face to the image sensor sensing face on the optical axis, Δ is at the absolute value of the longitudinal aberration of fraunhofer F curve and C curve (absolute value oflongitudinal chromatic aberrations at Fraunhofer F curve and C curvewavelengths), H-be the 3rd lens as the side optical surface point of inflexion with the length perpendicular to optical axis and optical axes crosspoint, H _tBe the 3rd lens as side optical surface greatest optical available point with the length perpendicular to optical axis and optical axes crosspoint, f ₁Be the effective focal length of first lens, f ₂Be the effective focal length of second lens, d ₃For first lens on the optical axis as the distance of lens thing side, side to the second, d ₅Be the distance of second lens on the optical axis as three lens thing sides, side to the, d ₇For the 3rd lens on the optical axis as the distance of side to infrared filter thing side, d ₉For infrared filter on the optical axis as the distance of side to the image sensor sensing face, R ₂₁Be the radius-of-curvature of the second lens thing side, and R ₂₂Be the radius-of-curvature of second lens as the side.

By this, make the utility model effectively revise aberration, make sampling image lens have high-res and can effectively dwindle lens length, reach the effect of miniaturization and lower cost, use the application that promotes sampling image lens.

Description of drawings

Fig. 1 is the optical texture synoptic diagram of the utility model first embodiment;

Fig. 2 is the point of inflexion synoptic diagram of the 3rd lens of the present utility model;

Fig. 3 is the curvature of field (field curvature) figure of the utility model first embodiment imaging;

Fig. 4 is distortion (distortion) figure of the imaging of the utility model first embodiment;

Fig. 5 is the optical texture synoptic diagram of the utility model second embodiment;

Fig. 6 is the curvature of field of the imaging of the utility model second embodiment;

Fig. 7 is the distortion figure of the imaging of the utility model second embodiment;

Fig. 8 is the optical texture synoptic diagram of the utility model the 3rd embodiment.

Fig. 9 is the curvature of field figure of the imaging of the utility model the 3rd embodiment;

Figure 10 is the distortion figure of the imaging of the utility model the 3rd embodiment;

Figure 11 is the optical texture synoptic diagram of the utility model the 4th embodiment;

Figure 12 is the curvature of field figure of the imaging of the utility model the 4th embodiment; And

Figure 13 is the distortion figure of the imaging of the utility model the 4th embodiment.

Description of reference numerals:

L1-first lens; The 11-first lens thing side; 12-first lens are as the side; The 13-aperture diaphragm; L2-second lens; The 21-second lens thing side; 22-second lens are as the side; L3-the 3rd lens; 31-the 3rd lens thing side; 32-the 3rd lens are as the side; The 4-infrared filter; The 5-image sensor; The last first lens thing side of d2-optical axis Z is to the picture lateral distance; Last first lens of d3-optical axis Z are as side to the second lens thing lateral distance; The last second lens thing side of d4-optical axis Z is to the picture lateral distance; Last second lens of d5-optical axis Z are as side to the three lens thing lateral distance; Last the 3rd lens thing side of d6-optical axis Z is to the picture lateral distance; Last the 3rd lens of d7-optical axis Z as the side to infrared filter thing lateral distance; D8-optical axis Z goes up infrared filter thing side to the picture lateral distance; D9-optical axis Z go up infrared filter as the side to the image sensor surface distance.

Embodiment

For making the utility model clear and definite more full and accurate, enumerate preferred embodiment now and cooperate following diagram, structure of the present utility model and technical characterictic are described in detail as the back:

With reference to shown in Figure 1, the utility model is the burnt small-sized prismatic glasses optical shooting lens in a short back, and it is arranged by the thing side along optical axis Z and extremely comprises in regular turn as side: one first lens L1, an aperture diaphragm 13, one second lens L2, one the 3rd lens L3, an infrared filter (IR cut-off filter) 4 and one image sensor (image sensing chip) 5; During capture, the light of thing (object) is first through behind the first lens L1, the second lens L2 and the 3rd lens L3, images on the image sensor 5 through infrared filter 4 again.

These first lens L1 has positive diopter, it is a meniscus non-spherical lens, can utilize refractive index (Nd1) greater than 1.5, Abbe number (vd1) makes greater than 50 glass or plastic cement material, and its convex surface (thing side) the 11st, towards the thing side and its concave surface (as the side) the 12nd, towards the picture side, its convex surface 11 and concave surface 12 have at least one side to be aspheric surface or the two-sided aspheric surface that is again.

These second lens L2 has negative diopter, it is a meniscus non-spherical lens, can utilize refractive index Nd2 greater than 1.56, Abbe number vd2 makes greater than 25 glass or plastic cement material, and its convex surface 21 is towards concave surface 22 is towards the thing side as side, and its convex surface 21 and concave surface 22 have at least one side to be aspheric surface or the two-sided aspheric surface that is again.On easy design and making, on second lens design, adopt relatively long focal length, or the absolute value numeral of formula (4) is reduced, to shorten back focal length.

The 3rd lens L 3 one has the non-spherical lens that negative diopter fades to positive diopter, can utilize refractive index Nd3 greater than 1.5, Abbe number vd3 makes greater than 55 glass or plastic cement material, the convex surface of its lens center be towards the thing side and concave surface be towards the picture side, and become positive diopter for negative diopter through the point of inflexion (inflection point) to rims of the lens from the lens center, its section presents the recessed and both sides of central authorities and protrudes as the shape of M font as shown in Figure 2, just in the optics effective diameter thing side 31 and as side 32 the convex surface of dipped beam axle/or concave surface be to gradually change radian (curvature) and be transformed into concave surface/or convex surface to rims of the lens, therefore the optical surface type change make diopter bear/just changing between formation one point of inflexion (inflectionpoint); When with arbitrary tangent line through the point of inflexion and with optical axis with square crossing, be the lens height of negative diopter scope as side 32 to optical axis distance from the point of inflexion, be designated as H-, as shown in Figure 2, be the 3rd lens as side 32 points of inflexion with length perpendicular to optical axis and optical axes crosspoint; The 3rd lens are as the greatest optical available point of side 32 vertical range to optical axis, be designated as Ht, be the 3rd lens as side 32 greatest optical available points with length perpendicular to optical axis and optical axes crosspoint, the ratio of H-and Ht is converted into the range size of positive diopter for negative diopter, for good imaging effect can be arranged, negative dioptric scope is preferable 38%～70%, promptly satisfies formula (3).

This infrared filter 4 can be an eyeglass, or utilizes coating technique formation one to have the film of infrared ray filtering functions.

This image sensor 5 comprises CCD (charge-coupled device (CCD)) or CMOS (complementary metal oxide semiconductor (CMOS)).

This aperture diaphragm (aperture stop) 13 belongs to a kind of mid-aperture, and it is located between the first lens L1 and the second lens L2 as shown in Figure 1; This aperture diaphragm 13 also can be located on the concave surface (as the side) 12 of the first lens L1 again.

The utility model optical shooting lens satisfies following formula (1)～formula (7) condition:

$0.25\&le;\frac{\mathrm{bf}}{\mathrm{TL}}\&le;0.4---\left(1\right)$

$0.001\&le;\frac{\mathrm{\&Delta;}}{f}\&le;0.006---\left(2\right)$

$0.38\&le;\frac{H_{-}}{H_t}\&le;0.7---\left(3\right)$

$-0.12\&le;\frac{f_1}{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="H2009201568524E00072.png,H2009201568524E00081.png"\; state="\{\{state\}\}">f</figure-callout>}}_2}\&le;-0.01---\left(4\right)$

$0.25\&le;\frac{d_3+{\mathrm{<figure-callout\; id="5"\; label="d"\; filenames="H2009201568524E00011.png,H2009201568524E00041.png"\; state="\{\{state\}\}">d</figure-callout>}}_5+d_7+d_9}{f}\&le;0.5---\left(5\right)$

$0.7\&le;\frac{f_1}{f}\&le;1.2---\left(6\right)$

$-0.2\&le;\frac{R_{21}-R_{22}}{{\mathrm{<figure-callout\; id="21"\; label="R"\; filenames="H2009201568524E00011.png,H2009201568524E00041.png"\; state="\{\{state\}\}">R</figure-callout>}}_{21}+{\mathrm{<figure-callout\; id="22"\; label="R"\; filenames="H2009201568524E00011.png,H2009201568524E00081.png"\; state="\{\{state\}\}">R</figure-callout>}}_{22}}\&le;-0.06---\left(7\right)$

For reaching the utility model purpose, it is preferable being aspheric surface with the optical surface that designs the first lens L1, the second lens L2 or the 3rd lens L3, but not as limit, and its aspheric equation (AsphericalSurface Formula) is formula (8):

$Z=\frac{{\mathrm{<figure-callout\; id="2"\; label="ch"\; filenames="H2009201568524E00072.png,H2009201568524E00081.png"\; state="\{\{state\}\}">ch</figure-callout>}}^2}{1+\sqrt{(1-(1+K)c^2{h}^2)}}+A_4{\mathrm{<figure-callout\; id="4"\; label="h"\; filenames="H2009201568524E00011.png"\; state="\{\{state\}\}">h</figure-callout>}}^4+A_6{h}^6+A_8{\mathrm{<figure-callout\; id="8"\; label="h"\; filenames="H2009201568524E00081.png"\; state="\{\{state\}\}">h</figure-callout>}}^8+A_{10}{h}^{10}+A_{12}{\mathrm{<figure-callout\; id="12"\; label="h"\; filenames="H2009201568524E00011.png,H2009201568524E00041.png"\; state="\{\{state\}\}">h</figure-callout>}}^{12}+A_{14}{h}^{14}$

(8)

Wherein, Z is that any point is with the distance (SAG) of optical axis direction to 0 section of eyeglass on the eyeglass, and c is a curvature, and h is the eyeglass height, and K is circular cone coefficient (Conic Constant), the A4～A14 asphericity coefficient of four～ten quadravalences respectively.

The material of first and second and three lens L1, L2, L3 is the basic comprising of sampling image lens, and it respectively can be plastic cement or glass is made.By said structure, can effectively revise aberration and reduce chief ray angle, make the utility model sampling image lens have high-res and can effectively dwindle lens length and shorten back focal length, reach the effect of miniaturization and lower cost.

Now enumerate preferred embodiment, and be respectively described below:

＜the first embodiment 〉

With reference to figure 1,3,4, it is respectively the structural drawing of the utility model sampling image lens first embodiment, the curvature of field of imaging (field curvature) figure and distortion (distortion) figure.

Show respectively in the following tabulation () by the thing side to the optical surface number of numbering in regular turn as side, the radius of curvature R of each optical surface on the optical axis (unit: mm) on (the radius of curvature R), the optical axis between each face apart from d (the on-axis surface spacing), the refractive index Nd of each lens, the Abbe number of each lens (Abbe ' s number) vd, focal length (focal length) f, visual angle (Field of view) FOV.

Table (one)

* represent the As aspheric surface

Every coefficient of the aspheric surface formula (8) of each optical surface is shown in following tabulation (two):

Table (two)

In the present embodiment, the first lens L1 be utilize that refractive index Nd1 is 1.54, Abbe number vd1 is that 56.1 plastic cement material is made; The second lens L2 be utilize that refractive index Nd2 is 1.58, Abbe number vd2 is that 30 plastic cement material is made; The 3rd lens L3 be utilize that refractive index Nd3 is 1.53, Abbe number vd3 is that 56 plastic cement material is made; Infrared filter 4 uses the BSC7 glass material to make.

The effective focal length f of system of present embodiment is 2.7468mm, and the focal distance f 1 of the first lens L1 is positioned at 1.42mm for-11.3204mm, the 3rd lens as the point of inflexion of side optical surface 32 for the-focal distance f 3 of 41.4011mm, the 3rd lens L3 for the focal distance f 2 of 2.2384mm, the second lens L2; Each value as table (three) can satisfy formula (1)-Shi (7) condition in formula (1)～formula (7).

Table (three)

By above-mentioned each table and diagram, the camera lens total length of present embodiment sampling image lens is TL=3.0952mm, back focal length bf=0.92mm as can be known, provable by this sampling image lens of the present utility model can effectively be revised aberration, makes sampling image lens have high-res and can effectively dwindle lens length again and shorten back focal length.

＜the second embodiment 〉

Shown in figure 5,6,7, it is respectively the structural drawing of the utility model sampling image lens second embodiment, the curvature of field of imaging (field curvature) and distortion (distortion) figure.

Show respectively in the following tabulation (four) by the thing side to the optical surface number of numbering in regular turn as side, on the radius of curvature R of each optical surface on the optical axis, the optical axis between each face apart from d, the Abbe number vd of the refractive index of each lens (Nd), each lens, focal distance f, a visual angle FOV.

Table (four)

* represent the As aspheric surface

Every coefficient of the aspheric surface formula (8) of each optical surface is shown in following tabulation (five):

Table (five)

In the present embodiment, the first lens L1 utilizes that refractive index Nd1 is 1.54, Abbe number vd1 is that 56.1 plastic cement material is made; The second lens L2 utilizes that refractive index Nd2 is 1.61, Abbe number vd2 is that 26 plastic cement material is made; The 3rd lens L3 utilizes that refractive index Nd3 is 1.53, Abbe number vd3 is that 56 plastic cement material is made; Infrared filter 4 uses the BSC7 glass material to make.

The effective focal length f of system of present embodiment is 2.7706mm, and the focal distance f 1 of the first lens L1 is positioned at 1.52mm for-12.4237mm, the 3rd lens as the point of inflexion of side optical surface 32 for the-focal distance f 3 of 22.6801mm, the 3rd lens L3 for the focal distance f 2 of 2.2888mm, the second lens L2; Each value as table (six) in formula (1)～formula (7), can satisfy formula (1)-Shi (7) condition:

Table (six)

By above-mentioned each table and diagram, the camera lens total length of present embodiment sampling image lens is TL=3.0315mm, back focal length bf=0.93mm as can be known, provable by this sampling image lens of the present utility model can effectively be revised aberration, makes sampling image lens have high-res and can effectively dwindle lens length again and shorten back focal length.

＜the three embodiment 〉

With reference to figure 8,9,10, it is respectively the structural drawing of the utility model sampling image lens the 3rd embodiment, the curvature of field and the distortion figure of imaging.

Show respectively in the following tabulation (seven) by the thing side to the optical surface number of numbering in regular turn as side, on the radius of curvature R of each optical surface on the optical axis, the optical axis between each face apart from d, the Abbe number vd of the refractive index of each lens (Nd), each lens, focal distance f, a visual angle FOV.

Table (seven)

* represent the As aspheric surface

Every coefficient of the aspheric surface formula (8) of each optical surface is shown in following tabulation (eight):

Table (eight)

In the present embodiment, the first lens L1 utilizes that refractive index Nd1 is 1.54, Abbe number vd1 is that 56.1 plastic cement material is made; The second lens L2 utilizes that refractive index Nd2 is 1.61, Abbe number vd2 is that 26 plastic cement material is made; The 3rd lens L3 utilizes that refractive index Nd3 is 1.53, Abbe number vd3 is that 56 plastic cement material is made; Infrared filter 4 uses the BSC7 glass material to make.

The effective focal length f of system of present embodiment is 2.8261mm, and the focal distance f 1 of the first lens L1 is positioned at 1.86mm for-132.2025mm, the 3rd lens as the point of inflexion of side optical surface 32 for the-focal distance f 3 of 100.0013mm, the 3rd lens L3 for the focal distance f 2 of 2.8822mm, the second lens L2; Each value as table (nine) in formula (1)～formula (7), can satisfy formula (1)～formula (7) condition:

Table (nine)

By above-mentioned each table and diagram, the camera lens total length of present embodiment sampling image lens is TL=3.5413mm, back focal length bf=0.95mm as can be known, provable by this sampling image lens of the present utility model can effectively be revised aberration, makes sampling image lens have high-res and can effectively dwindle lens length again and shorten back focal length.

＜the four embodiment 〉

Shown in Figure 11,12,13, it is respectively the structural drawing of the utility model sampling image lens the 4th embodiment, the curvature of field and distortion (distortion) figure of imaging.

Show respectively in the following tabulation (ten) by the thing side to the optical surface number of numbering in regular turn as side, on the radius of curvature R of each optical surface on the optical axis, the optical axis between each face apart from d, the Abbe number vd of the refractive index of each lens (Nd), each lens, focal distance f, a visual angle FOV.

Table (ten)

* represent the As aspheric surface

The every coefficient of aspheric surface formula (8) of each optical surface is shown in following tabulation (11):

Table (11)

In the present embodiment, the first lens L1 utilizes that refractive index Nd1 is 1.59, Abbe number vd1 is that 61.2 glass material is made; The second lens L2 utilizes that refractive index Nd2 is 1.69, Abbe number vd2 is that 31.1 glass material is made; The 3rd lens L3 utilizes that refractive index Nd3 is 1.59, Abbe number vd3 is that 61.2 glass material is made; Infrared filter 4 uses the BSC7 glass material to make.

The effective focal length f of system of present embodiment is 2.6249mm, and the focal distance f 1 of the first lens L1 is positioned at 1.48mm for-51.9728mm, the 3rd lens as the point of inflexion of side optical surface 32 for the-focal distance f 3 of 95.1835mm, the 3rd lens L3 for the focal distance f 2 of 2.2536mm, the second lens L2; Each value as table (12) in formula (1)～formula (7), can satisfy formula (1)～formula (7) condition:

Table (12)

By above-mentioned each table and diagram, the camera lens total length of present embodiment sampling image lens is TL=3.4426mm, back focal length bf=1.07mm as can be known, provable by this sampling image lens of the present utility model can effectively be revised aberration, makes sampling image lens have high-res and can effectively dwindle lens length again and shorten back focal length.

Above embodiment only is preferred embodiment of the present utility model, and it is illustrative for the utility model, and nonrestrictive.Those skilled in the art carries out conversion, modification even equivalence to it under the situation that does not exceed the utility model spirit and scope, these changes all can fall into claim protection domain of the present utility model.

Claims (8)

1. the one kind short burnt small-sized prismatic glasses optical shooting lens in back is characterized in that, arranges by the thing side along optical axis extremely to comprise in regular turn as side:

One first lens have positive diopter, and it is a meniscus non-spherical lens, and its convex surface be towards the thing side and its concave surface be towards the picture side;

One second lens have negative diopter, and it is a meniscus non-spherical lens, and its convex surface is towards concave surface is towards the thing side as side;

One the 3rd lens, it on optical axis a negative dioptric non-spherical lens, its lens center is positioned on the optical axis, and the lens center convex surface is towards the thing side and concave surface is towards the picture side, and becomes positive diopter for negative diopter through the point of inflexion to rims of the lens from the lens center; Meet the following conditions:

$0.25\&le;\frac{\mathrm{bf}}{\mathrm{TL}}\&le;0.4;$

$0.001\&le;\frac{\mathrm{\&Delta;}}{f}\&le;0.006;$

$0.38\&le;\frac{H_{-}}{H_t}\&le;0.7;$

$-0.12\&le;\frac{f_1}{f_2}\&le;-0.01;$

Wherein, f is the effective focal length of this sampling image lens system, bf is the back focal length of this sampling image lens system, TL is that the first lens thing is surveyed the total length of face to the image sensor sensing face on the optical axis, Δ is the absolute value at the longitudinal aberration of fraunhofer F line taking and C curve, H-be the 3rd lens as the side optical surface point of inflexion with the length perpendicular to optical axis and optical axes crosspoint, H _tBe the 3rd lens as side optical surface greatest optical available point with the length perpendicular to optical axis and optical axes crosspoint, f ₁Be the effective focal length of first lens, f ₂It is the effective focal length of second lens.

2. the burnt small-sized prismatic glasses optical shooting lens in short back as claimed in claim 1 is characterized in that, between these first lens and second lens aperture diaphragm is set.

3. the burnt small-sized prismatic glasses optical shooting lens in short back as claimed in claim 2 is characterized in that this aperture diaphragm is located on the concave surface of first lens.

4. the burnt small-sized prismatic glasses optical shooting lens in short back as claimed in claim 1 is characterized in that the focal length and the distance between lens of these first lens further satisfy following condition:

$0.25\&le;\frac{d_3+d_5+d_7+d_9}{f}\&le;0.5;$

$0.7\&le;\frac{f_1}{f}\&le;1.2;$

Wherein, f is the effective focal length of this sampling image lens system, f ₁Be the effective focal length of first lens, f ₂Be the effective focal length of second lens, d ₃For first lens on the optical axis as the distance of lens thing side, side to the second, d ₅Be the distance of second lens on the optical axis as three lens thing sides, side to the, d ₇For the 3rd lens on the optical axis as the distance of side to infrared filter thing side, d ₉For infrared filter on the optical axis as the distance of side to the image sensor sensing face.

5. the burnt small-sized prismatic glasses optical shooting lens in short back as claimed in claim 1 is characterized in that these second lens further satisfy following condition:

$-0.2\&le;\frac{R_{21}-R_{22}}{R_{21}+R_{22}}\&le;-0.06;$

Wherein, R ₂₁Be the radius-of-curvature of the second lens thing side, R ₂₂Be the radius-of-curvature of second lens as the side.

6. the burnt small-sized prismatic glasses optical shooting lens in short back as claimed in claim 1 is characterized in that these first lens, second lens and the 3rd lens are made by plastic cement material.

7. the burnt small-sized prismatic glasses optical shooting lens in short back as claimed in claim 1 is characterized in that these second lens are made by glass material.

8. the burnt small-sized prismatic glasses optical shooting lens in short back as claimed in claim 1 is characterized in that these first lens and the 3rd lens are made by glass material.

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