CN2609005Y - Wide angle projection optical system possessing long back focal distance - Google Patents

Wide angle projection optical system possessing long back focal distance Download PDF

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Publication number
CN2609005Y
CN2609005Y CN 03225024 CN03225024U CN2609005Y CN 2609005 Y CN2609005 Y CN 2609005Y CN 03225024 CN03225024 CN 03225024 CN 03225024 U CN03225024 U CN 03225024U CN 2609005 Y CN2609005 Y CN 2609005Y
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lens
positive
optical system
negative
projection optical
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詹达举
王芳芹
张建平
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Butterfly Technology Shenzhen Ltd
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ANGNAMINGDA NETWORK TECHNOLOGY
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Abstract

The utility model provides a wide angle projection optic system with a long arm focus. The utility model comprises a front lens part one with negative refracted light lens strength and a back lens part two with positive refracted light lens strength. The front lens part one takes spherical lenses or comprises a non-spherical lens. The lens compound light strength of the front lens part one satisfies the absolute value of f # minus [comb.] is lager than 1.5 and less than 2.5 f, and f # minus [comb.] is less than 0; wherein f # minus [comb.] is the combined focus of each lens in the front lens part. The back lens part two comprises a group of cemented doublelet with negative refracted light power, two groups of positive, negative and positive cemented triplet with positive refracted light power, and a positive lens with positive refracted light power. The utility model completely satisfies all the performance indexes requirements from rear projected televisions by reasonably choosing and assembling to the structure and the parametric of each lens, and achieves projection results of large-screen, small thickness and high image quality.

Description

A kind of wide-angle projection optical system with long back of the body focal length
Technical field
The utility model relates to optical instrument, especially relates to a kind of projection optical system.
Background technology
In recent years, large-curtain projecting TV set has obtained development fast and has progressively entered family.The appearance of multiple shadow casting technique, as plasma, high temperature polysilicon (HTP-LCD), digital light is handled (DLP) etc., makes large-screen color TV enter a kind of technical competition period.
In large-curtain projecting TV set, projection optical system is very important equipment, and its performance index must meet the demands, and this directly has influence on the quality of large-curtain projecting TV set.
Projection TV requires to have very short projector distance so that projection TV can do short and smallly, frivolous.In other words, under the constant condition of projected area, require projection lens that a bigger field angle will be arranged.Because projection lens will cooperate various chips to use, it requires projection lens that low f-number F must be arranged #(f/2.8 or littler) satisfies the brightness of projection TV, and the uniformity requirement of camera lens is than higher (generally greater than 90%), to reduce the phenomenon of four jiaos of obfuscation of projection.Again because HTP-LCD, DLP, the brilliant reflection of base fluid (LCOS) pixel cell is smaller, requires projection lens that high projected resolution will be arranged, to satisfy the requirement of projection.
Owing in the projection TV, need carry out beam split to white light with prism, and RGB (RGB) look is closed light, therefore, require camera lens that long back of the body focal length is arranged.Projection lens needs image projection is amplified at work, and the RGB three primary colours is assembled disadvantageous effect, the result of misconvergence are arranged is to make color separately, influences the image quality of projection, therefore, requires projection lens that very little chromatic longitudiinal aberration is arranged.
Projection television picture is many based on 4: 3 and 16: 9, and the distortion of camera lens is had strict requirement, can not allow the human eye perceives picture that the phenomenon of distortion is arranged, so the distortion of camera lens generally requires less than 1%.
But existing projection optical system can not satisfy all these performance index well simultaneously.Wide-angle lens described in U.S. Pat 2002/0154418, it is mainly used in off-axis projection system, and is incompatible for on-axis projection system.Projection lens described in U.S. Pat 6188523, adopted the semicolumn eyeglass in its lens system, make incident ray after reflection enters camera lens, form and depart from from axle, thus the volume of minimizing system, but the design of this semicolumn eyeglass makes its manufacturing accuracy be difficult to guarantee.In the projection lens example described in U.S. Pat 6471359, its back of the body focal length (BFL) can not meet the requirement of the projection lens with longer back of the body focal length less than 58mm.
Summary of the invention
The purpose of this utility model is to solve existing projection optical system can not satisfy the problem of the desired all properties index of back projection TV simultaneously, and a kind of giant-screen that satisfies is provided, little thickness, the projection optical system that high image quality requires.
The purpose of this utility model is achieved in that a kind of wide-angle projection optical system with long back of the body focal length, comprises that one has the preceding camera lens part I of negative refraction focal power and the rear lens part II that has the positive refraction focal power;
It is characterized in that described preceding camera lens part I all uses global face lens, comprises 5 lens, is docile and obedient preface from projecting into image planes, the 1st lens are a negative meniscus L 1, the 2nd lens are a falcate positive lens L 2, the 3rd lens are a negative meniscus L 3, the 4th lens are a negative meniscus L 4, the 5th lens are a double-concave negative lens L 5
The combined light focal power of camera lens part I satisfies following relation before described:
1.5f<| f Close|<2.5f, f Close<0
F wherein CloseBe the 1st lens L 1, the 2nd lens L 2, the 3rd lens L 3, the 4th lens L 4With the 5th lens L 5Combined focal length, f is the focal length of whole projection optical system.
Described rear lens part II comprises 9 lens, be docile and obedient preface begin after the camera lens part I in the past for: by the 6th lens L 6With the 7th lens L 7One group of cemented doublet with negative refraction focal power being formed is by the 8th lens L 8, the 9th lens L 9, the 10th lens L 10With by the 11st lens L 11, the 12nd lens L 12, the 13rd lens L 13Two groups that are formed have positive and negative positive three balsaming lenss of positive refraction focal power and lens the 14th lens L that a slice has the positive refraction focal power 14
To reduce systematical distortion in order reducing, to reduce eyeglass quantity, also can use non-spherical lens, be docile and obedient preface and begin to be a falcate aspheric surface negative lens L from projecting into image planes at preceding camera lens part I 1 ', a falcate positive lens L 2 ', a negative meniscus L 3 ', another negative meniscus L 4 '
The combined light focal power of camera lens part I satisfies following relation before described:
1.5f<|f (1’,2’,3’,4’)|<2.5f,f (1’,2’,3’,4’)<0
F wherein (1 ', 2 ', 3 ', 4 ')Be preceding camera lens L 1 ', L 2 ', L 3 ', L 4 'The combined focal length of camera lens.
In order further to reduce material cost, the eyeglass quantity of preceding camera lens part I can also be reduced to 3.Be docile and obedient preface and begin to be falcate aspheric surface negative lens L from projecting into image planes 1 ", a negative meniscus L 2 ", a negative meniscus L 3 "
The combined light focal power of camera lens part I satisfies following relation before described:
1.5f<|f (1”,2”,3”)|<2.5f,f (1”,2”,3”)<0
F wherein (1 ", 2 ", 3 ")Be preceding camera lens L 1 ", L 2 ", L 3 "The combined focal length of camera lens.
According to the wide-angle projection optical system with long back of the body focal length described in the utility model, it is characterized in that described rear lens part II satisfies following relation:
(2)|V 7-V 6|>20 (3)n 6>1.75
(4)n 8<1.55 (5)n 10<1.55
(6)n 11<1.55 (7)n 13<1.55
(8)n 14<1.55 (9)V 6<28
(10)V 8>60 (11)V 10>60
(12)V 11>60 (13)V 13>60
(14)V 14>60 (15)1.2<R 13/f<2.8
(16)1.0<R 15/f<2.6 (17)1.6<R 19/f<3.2
(18)3.5f<f back<4.8f
Wherein f is the focal length of whole projection optical system; f BackIt is the rear cut-off distance of described whole projection optical system; n 6, n 8, n 10, n 11, n 13, n 14Difference the 6th lens L 6, the 8th lens L 8, the 10th lens L 10, the 11st lens L 11, the 13rd lens L 13, the 14th lens L 14Refraction coefficient; V 6, V 7, V 8, V 10, V 11, V 13, V 14Be respectively the 6th lens L 6, the 8th lens L 8, the 10th lens L 10, the 11st lens L 11, the 13rd lens L 13, the 14th lens L 14Abbe constant; R 13Be the 7th lens L 7The radius of face shape; R 15Be the 8th lens L 8With the 9th lens L 9The radius of cemented surface; R 19Be the 11st lens L 11With the 12nd lens L 12The radius of cemented surface.
According to the wide-angle projection optical system with long back of the body focal length described in the utility model, it is characterized in that, between first lens of the last a slice lens of preceding camera lens I and rear lens II, place the diaphragm sheet.
Implement projection optical system of the present utility model,, can satisfy the desired all properties index of back projection TV fully, realize giant-screen, little thickness, the drop shadow effect of high image quality by choose reasonable and combination to the structure and parameter of each lens.The utility model is simple in structure, and is cheap for manufacturing cost, has very strong practicality.
Description of drawings
Fig. 1 is the optical system configuration composition that the utlity model has the embodiment one of the wide-angle projection optical system of growing back of the body focal length;
Fig. 2 is the optical system configuration composition that projection optical system shown in Figure 1 is rotated through optical axis;
Fig. 3 is the spherical aberration curve of projection optical system shown in Figure 1;
Fig. 4 is the astigmatism and the distortion curve of projection optical system shown in Figure 1;
Fig. 5 is the ratio chromatism, curve of projection optical system shown in Figure 1;
Fig. 6 is the modulation transfer function (MTF) curve of projection optical system shown in Figure 1;
Fig. 7 is the optical system configuration composition that the utlity model has the embodiment two of the wide-angle projection optical system of growing back of the body focal length;
Fig. 8 is the optical system configuration composition that projection optical system shown in Figure 7 is rotated through optical axis;
Fig. 9 is the spherical aberration curve of projection optical system shown in Figure 7;
Figure 10 is the astigmatism and the distortion curve of projection optical system shown in Figure 7;
Figure 11 is the ratio chromatism, curve of projection optical system shown in Figure 7;
Figure 12 is the MTF curve of projection optical system shown in Figure 7;
Figure 13 is the optical system configuration composition that the utlity model has the embodiment three of the wide-angle projection optical system of growing back of the body focal length;
Figure 14 is the optical system configuration composition that projection optical system shown in Figure 13 is rotated through optical axis;
Figure 15 is the spherical aberration curve of projection optical system shown in Figure 13;
Figure 16 is the astigmatism and the distortion curve of projection optical system shown in Figure 13;
Figure 17 is the ratio chromatism, curve of projection optical system shown in Figure 13;
Figure 18 is the MTF curve of projection optical system shown in Figure 13.
Embodiment
Embodiment one
As shown in Figure 1, in the present embodiment, the wide-angle projection optical system with long back of the body focal length comprises that one has the preceding camera lens part I of negative refraction focal power and the rear lens part II that has the positive refraction focal power.
Preceding camera lens part I all uses global face lens, comprises 5 lens, is docile and obedient preface from projecting into image planes, and the 1st lens are a negative meniscus L 1, the 2nd lens are a falcate positive lens L 2, the 3rd lens are a negative meniscus L 3, the 4th lens are a negative meniscus L 4, the 5th lens are a double-concave negative lens L 5
The combined light focal power of preceding camera lens part I satisfies following relation:
(1)1.5f<|f (1,2,3,4,5)|<2.5f,f (1,2,3,4,5)<0
F wherein (1,2,3,4,5)L for preceding camera lens I 1, L 2, L 3, L 4, L 5The combined focal length of lens.
If f (1,2,3,4,5)Value near lower limit, i.e. 1.5f, before will strengthening lens group disperse refractive optical power, then increase negative distortion, make the distortion correction difficulty, so the value in the condition (1) should be greater than 1.5f.
If f (1,2,3,4,5)Value near the upper limit, i.e. 2.5f.To weaken and disperse refractive optical power, can not obtain the requirement of long back of the body focal length, so the value in the condition (1) should be less than 2.5f.
Rear lens part II comprises 9 lens, be docile and obedient preface begin after the camera lens part I in the past for:
By the 6th lens L 6With the 7th lens L 7One group of cemented doublet with negative refraction focal power being formed is by the 8th lens L 8, the 9th lens L 9, the 10th lens L 10With by the 11st lens L 11, the 12nd lens L 12, the 13rd lens L 13Two groups that are formed have positive and negative positive three balsaming lenss of positive refraction focal power and lens the 14th lens L that a slice has the positive refraction focal power 14
Each lens of rear lens part II satisfy following relation:
(2)|V 7-V 6|>20 (3)n 6>1.75
(4)n 8<1.55 (5)n 10<1.55
(6)n 11<1.55 (7)n 13<1.55
(8)n 14<1.55 (9)V 6<28
(10)V 8>60 (11)V 10>60
(12)V 11>60 (13)V 13>60
(14)V 14>60 (15)1.2<R 13/f<2.8
(16)1.0<R 15/f<2.6 (17)1.6<R 19/f<3.2
(18)3.5f<f back<4.8f
Wherein f is the focal length of whole projection optical system; f BackIt is the rear cut-off distance of described whole projection optical system; n 6, n 8, n 10, n 11, n 13, n 14Difference the 6th lens L 6, the 8th lens L 8, the 10th lens L 10, the 11st lens L 11, the 13rd lens L 13, the 14th lens L 14Refraction coefficient; V 6, V 7, V 8, V 10, V 11, V 13, V 14Be respectively the 6th lens L 6, the 8th lens L 8, the 10th lens L 10, the 11st lens L 11, the 13rd lens L 13, the 14th lens L 14Abbe constant; R 13Be the 7th lens L 7The radius of face shape; R 15Be the 8th lens L 8With the 9th lens L 9The radius of cemented surface; R 19Be the 11st lens L 11With the 12nd lens L 12The radius of cemented surface.
Wherein, if | V 7-V 6| then unfavorable less than 20 to the correction of ratio chromatism, and spherochromatism, so should guarantee | V 7-V 6|>20.
Wherein, n 8, n 10, n 11, n 13, n 14Less,<1.55, V 8, V 10, V 11, V 13, V 14Bigger,>60, favourable for the correction of spherochromatism and ratio chromatism.
Wherein, 1.2<R 13/ f<2.8.Because, if R 13/ f value is lower than lower limit, and promptly 1.2, system will produce high-order spherical aberration and coma, be unfavorable for the correction of system aberration.If R 13/ f value is higher than the upper limit, and promptly 2.8, unfavorable to the correction of pixel.In like manner, also should satisfy following relation, 1.0<R 15/ f<2.6,1.6<R 19/ f<3.2.
Last a slice lens L at preceding camera lens part I 5First lens L with rear lens part II 6Between place the diaphragm sheet.As the minimum luminous flux that limits whole optical system, guarantee the quality of imaging.If among the camera lens I, system will produce a large amount of barrel distortion aberrations, be not easy to the correction of aberration before diaphragm is placed on; If diaphragm is placed among the rear lens II, will be to satisfying the beam projecting angle at optical system edge | the requirement of u|<1 ° causes adverse effect, unless change each power of lens and at interval.
In order more effectively to reduce the distance of light path system, the direction that changes projection to be to satisfy the short and small frivolous requirement of projection TV, as shown in Figure 2, and can be at last a slice lens L of preceding camera lens part I 5First lens L with rear lens part II 6Between add a slice reflective mirror M, make 90 °>θ of the optical axis anglec of rotation>45 °, changing the optical axis direction of camera lens, thereby change the projecting direction of camera lens.
Last a slice lens L of preceding camera lens part I 5First lens L with rear lens part II 6Space D 10Should satisfy following relation:
5f<D 10<10f
If D 10Near lower limit 5f, the correction of the aberration that is unfavorable for distorting, and the rotation of the optical axis of preceding camera lens part I and rear lens group II be easy to generate interference, inconvenience is with the angle of the optical axis of the optical axis that changes preceding camera lens part I and rear lens part II, so D 10Value should keep greater than 5f.
If D 10Near upper limit 10f, the correction of the aberration that helps distorting, but it will increase the diameter of the 1st, the 2 lens, make Lens increase, and increase material cost, so D 10Value should keep less than 10f.
Because of the projection chip has strict requirement to angle of incidence of light, then the edge chief ray should as far as possible vertically incide on the image planes, thereby improves the homogeneity of projection.Therefore, the angle u of visual field, edge chief ray and optical axis must satisfy | u|<1 °.
Therefore, the lens 13 of rear lens part II and lens 14 are the positive refraction focal power, and diaphragm is from R 24There is sufficiently long distance on the summit.Guarantee the diaphragm face to R24 vertex distance 7f<L<9f, L arrives R for the diaphragm center 24The distance on summit.If L<7f or L<9f, can not guarantee | u|<1 °, unless change the focal power of rear lens II combination.
The volume requirement of considering projection TV is short and small as much as possible, frivolous, then requires projector distance short more good more, that is to say in certain projected area, requires optical projection system maximum field of view angle to be the bigger the better, because 1.5f<| f (1,2,3,4,5)|<2.5f and f (1,2,3,4,5)<0, thus the optical system anti-far away system that is wide-angle, half-angle a>36 °.
Owing in the projection TV, need carry out beam split to white light with prism, and the RGB three primary colours are closed light, require light path system that long back of the body focal length is arranged.If back of the body focal length | f Back| be lower than lower limit 3.5f, will make prism L 15Middle D 24Must shorten, otherwise light path system can not be imaged on the projection chip image planes, but D 24Shortening cause prism L 15Logical light area reduce, just do not satisfy the requirement of projection chip maximum image height.If f BackBe higher than upper limit 4.8f, camera lens I combined focal length f before then requiring (1,2,3,4,5)Negative power increase, will influence (1) formula 1.5f<| f (1,2,3,4,5)| the desired lower limit of<2.5f, difficult more to distortion correction.So should guarantee 3.5f<f Back<4.8f makes optical system have the back of the body focal length of certain-length.If comprise the prism system L that increases among Fig. 1 15, prism system L 15Length D 24Satisfy 4f<D 24<5f, it carries on the back focal distance f Back1To extend to 5.0f<f Back1<7.0f.F wherein Back1Be R 23The summit to R 27The distance at center.
High-res is the major requirement of this design of Optical System, has the pixel more than 1,000,000 on the projection chip, and pixel size is in the magnitude of micron, by being projected on the screen after the optical system amplification, human eye is wanted to know resolution image, and do not have the obviously phenomenon of distortion, then the aberration that axle is gone up and axle is outer all will rationally obtain proofreading and correct, and can obtain optimized MTF curve.
Table 1 is to optimize acquisition according to the requirement of present embodiment in optics software Zemax board design.In table 1, OBT is an object distance, and STOP is the stop position, and IMG is the image planes position, and Radius represents radius-of-curvature, and Thickness represents the thickness of lens or the distance between lens, N dThe sodium light d line refraction coefficient of representing each lens, V dThe Abbe constant (Abbe) of representing each lens.Focal distance f=12mm, the aperture ratio is 1: 2.8, and the maximum field of view angle is 78 degree, and the unit of all distance measurements is a millimeter.
By the data of table 1 as can be known, in the present embodiment, back work distance f Back1=D 23+ D 24+ D 25+ D 26=73mm.f (1,2,3,4,5)=-20.13mm |V 7-V 6|=23.6n 6=1.84663 V 6=23.83n 8=1.470467 V 8=66.87n 10=1.470467 V 10=66.87n 11=1.48746 V 11=70.13n 13=1.48746 V 13=70.13n 14=1.470467 V 14=66.87R 13/f=1.94 R 15/f=1.58R 19/f=2.09 f back=50.7mmD 10=73.16mm
Radius Thickness Nd Vd
OBJ INFINITY 800
1 79.19788383 3.974832 1.806278 25.37
2 47.19939109 6.5211109
3 66.01542886 12.363672 1.788309 47.4
4 973.0534261 0.1
5 47.19939109 4.6702018 1.788309 47.4
6 20.8642916 8.5323485
7 119.2010379 2.8712569 1.788309 47.4
8 34.53381627 4.4401543
9 -161.7042254 4.3037314 1.788309 47.4
10 79.19788383 73.159273
Stop INFINITY 0
12 38.23877553 16.861636 1.846663 23.86
13 -38.23877553 2.3296556 1.788309 47.4
14 23.293524 0.1
15 20.8642916 13.623906 1.470462 66.87
16 -18.92298828 6.3911458 1.749504 34.99
17 54.94577347 7.3691954 1.470462 66.87
18 -32.16679487 0.1
19 57.85129752 9.0388593 1.48746 70.13
20 -25.07655559 4.8332873 1.749504 34.99
21 45.2540774 8.4676272 1.48746 70.13
22 -53.26240774 0.1
23 66.01542886 8.2788058 1.470462 66.87
24 -60.50557002 5
25 INFINITY 55 1.64769 33.84
26 INFINITY 12
27 INFINITY 1 1.5168 64.17
IMG INFINITY 0
Table 1
Above data satisfy the requirement of the desired all properties index of back projection TV.With reference to the MTF figure of the system aberration analytic curve of figure 3~Fig. 6 and comprehensive evaluation as can be known, the utility model by the lens that use global face can obtain good image quality wide-angle, grow the projection optical system of carrying on the back focal length.
Embodiment two
As shown in Figure 7, reduce systematical distortion, reduce eyeglass quantity, also can use non-spherical lens, be docile and obedient preface and begin to be a falcate aspheric surface negative lens L from projecting into image planes at preceding camera lens part I in order to reduce 1 ', a falcate positive lens L 2 ', a negative meniscus L 3 ', another negative meniscus L 4 'Described combined light focal power satisfies following relation:
1.5f<|f (1’,2’,3’,4’)|<2.5f,f (1’,2’,3’,4’)<0
F wherein (1 ', 2 ', 3 ', 4 ')Be preceding camera lens L 1 ', L 2 ', L 3 ', L 4, the combined focal length of camera lens.
In preceding camera lens I, use aspheric eyeglass.L 1 'Be aspherical lens, it satisfies following aspheric surface formula
Z = ch 2 1 + [ 1 - ( 1 + k ) c 2 h 2 ] 1 / 2 + A h 4 + Bh 6 + Ch 8 + Dh 10 + · · ·
Wherein c is the curvature of eyeglass, and h is the light coordinate of eyeglass, and K is a whose conic coefficient, A, and B, C, D are the coefficients on each rank of aspheric curve.
In order more effectively to reduce the distance of light path system, the direction that changes projection to be to satisfy the short and small frivolous requirement of projection TV, as shown in Figure 8, and can be at last a slice lens L of preceding camera lens part I 4And first lens L of rear lens part II 6Between add a slice reflective mirror M, make 90 °>θ of the optical axis anglec of rotation>45 °, changing the optical axis direction of camera lens, thereby change the projecting direction of camera lens.
Table 2 is to optimize acquisition according to the requirement of present embodiment in optics software Zemax board design.In table 2, OBT is an object distance, and STOP is the stop position, and IMG is the image planes position, and Radius represents radius-of-curvature, and Thickness represents the thickness of lens or the distance between lens, N dThe sodium light d line refraction coefficient of representing each lens, V dThe Abbe number of representing each lens.Focal distance f=12mm, the aperture ratio is 1: 2.8, and the maximum field of view angle is 78 degree, and the unit of all distance measurements is a millimeter.
Curvature Thickness Nd Vd
OBJ INFINITY 800.000000
1 100.539049 4.500000 1.491756 57.44
K=3.836742
A=5.74E-7 B=-9.27E-11 C=-3.27E-14 D=6.629E-18
2 21.000032 8.725641
K=-0.57960281
A=-4.12E-8 B=-3.52E-9 C=5.08E-12 D=-6.43E-15
3 46.12972528 10.287734 1.713 53.83
4 86.32992414 0.100000
5 76.6479168 2.800000 1.620415 60.27
6 27.78827325 7.133396
7 1947.168187 2.205217 1.620415 60.27
8 47.55027407 96.307948
Stop INFINITY 19.769165
10 46.17924474 16.589263 1.846663 23.86
11 -56.33946284 2.199383 1.788309 47.4
12 30.37139078 0.099802
13 25.83656738 11.284436 1.470462 66.87
14 -25.83656738 4.967501 1.749504 34.99
15 53.27706991 7.462946 1.470462 66.87
16 -40.12573318 0.100000
17 45.67354178 9.194517 1.48746 70.13
18 -32.27440994 2.200092 1.749504 34.99
19 30.11753912 7.911986 1.48746 70.13
20 -99.64477634 0.100000
21 49.52224405 8.359071 1.470462 66.87
22 -74.69539033 5.000000
24 INFINITY 55.000000 1.64769 33.84
25 INFINITY 12.000000
26 INFINITY 1.000000 1.5168 64.17
IMG INFINITY 0.000000
Table 2
By the data of table 2 as can be known, in the present embodiment, back work distance f Back1=D 23+ D 24+ D 25+ D 26=73mm.
f (1’,2’,3’,4’)=-22.5mm |V 7-V 6|=23.6
n 6=1.84663 V 6=23.83
n 8=1.470467 V 8=66.87
n 10=1.470467 V 10=66.87
n 11=1.48746 V 11=70.13
n 13=1.48746 V 13=70.13
n 14=1.470467 V 14=66.87
R 13/f=2.53 R 15/f=2.15
R 19/f=2.52 f back=50.8mm
D 10=116.07mm
Above data satisfy the requirement of the desired all properties index of back projection TV.With reference to the MTF figure of the system aberration analytic curve of figure 9~Figure 12 and comprehensive evaluation as can be known, the utility model can effectively reduce the numerical value of each aberration of system by using non-spherical lens, particularly distorts less than 0.25%.
Embodiment three
As shown in figure 13, in order to reduce eyeglass quantity, reduce material cost, the number of lenses of preceding camera lens I reduces to 3, and this part is docile and obedient preface from projecting into image planes: be a falcate aspheric surface negative lens L 1 ", a negative meniscus L 2 ", a negative meniscus L 3 "Preceding camera lens part I includes an aspheric surface negative lens at least.
1.5f<|f (1”,2”,3”)|<2.5f,f (1”,2”,3”)<0
F wherein (1 ", 2 ", 3 ")Be preceding camera lens L 1 ", L 2 ", L 3 "The combined focal length of camera lens.
In preceding camera lens I, use aspheric eyeglass.L 1 "Be aspherical lens, it satisfies following aspheric surface formula
Z = ch 2 1 + [ 1 - ( 1 + k ) c 2 h 2 ] 1 / 2 + A h 4 + B h 6 + C h 8 + D h 10 + · · ·
Wherein c is the curvature of eyeglass, and h is the light coordinate of eyeglass, and K is a whose conic coefficient, A, and B, C, D are the coefficients on each rank of aspheric curve.
In order more effectively to reduce the distance of light path system, the direction that changes projection to be to satisfy the short and small frivolous requirement of projection TV, as shown in figure 14, and can be at last a slice lens L of preceding camera lens part I 3 "First lens L with rear lens part II 6Between add a slice reflective mirror M, make 90 °>θ of the optical axis anglec of rotation>45 °, changing the optical axis direction of camera lens, thereby change the projecting direction of camera lens.
Table 3 is to optimize acquisition according to the requirement of present embodiment in optics software Zemax board design.The data that are displayed in Table 3, OBT is an object distance, and STOP is the stop position, and IMG is the image planes position, and Radius represents radius-of-curvature, Thickness represents the thickness of lens or the distance between lens, N dThe sodium light d line refraction coefficient of representing each lens, V dThe Abbe number of representing each lens.Focal distance f=11.8mm, the aperture ratio is 1: 2.8, and the maximum field of view angle is 78 degree, and the unit of all distance measurements is a millimeter.
In the present embodiment, back work distance f Back1=D 23+ D 24+ D 25+ D 26=73mm.
f (1”,2”,3”)=-25.1mm |V 7-V 6|=23.6
n 6=1.84663 V 6=23.83
n 8=1.470467 V 8=66.87
n 10=1.470467 V 10=66.87
n 11=1.48746 V 11=70.13
n 13=1.48746 V 13=70.13
n 14=1.470467 V 14=66.87
R 13/f=2.35 R 15/f=2.08
R 19/f=2.89 f back=51.82mm
D 10=112.4mm
Curvature Thickness Nd Vd
OBJ INFINITY 800.000000
1 62.230306 4.800000 1.491756 57.44
K=1.84742
A=3.288E-6 B=-4.415E-10 C=-9.22E-13 D=-2.517E-16
2 20.707949 13.725641
K=-0.51560281
A=5.39E-6 B=-2.86E-9 C=5.536E-11 D=-6.598E-14
3 138.742847 4.569988 1.62041 60.29
4 27.098357 6.440886
5 -272.873631 5.483986 1.51637 64.07
6 -638.951588 95.000000
Stop INFINITY 17.378932
8 42.833837 18.197056 1.846663 23.86
9 -54.494288 2.010795 1.788309 47.4
10 27.686994 0.091400
11 24.507690 10.604410 1.470462 66.87
12 -24.507690 2.010795 1.749504 34.99
13 48.550757 8.285863 1.470462 66.87
14 -36.098324 0.091400
15 63.260267 8.655883 1.48746 70.13
16 -34.240258 2.010795 1.749504 34.99
17 29.056727 8.485300 1.48746 70.13
18 -102.692541 0.091400
19 45.727307 8.970900 1.470462 66.87
20 -67.288824 5.000000
21 INFINITY 55.000000 1.64769 33.84
22 INFINITY 1 2.000000
23 INFINITY 1.000000 1.5168 64.17
IMG INFINITY 0.000000
Table 3
Above data satisfy the requirement of the desired all properties index of back projection TV.With reference to the MTF figure of the system aberration analytic curve of Figure 15~Figure 18 and comprehensive evaluation as can be known, the utility model can obtain the wide-angle of good image quality, the projection optical system of long back of the body focal length.As seen, guaranteeing under the condition constant to system requirements that present embodiment is by using non-spherical lens, employed lens have reduced 2 than embodiment one, have reduced material cost.

Claims (8)

1. the wide-angle projection optical system with long back of the body focal length comprises that one has the preceding camera lens part I of negative refraction focal power and the rear lens part II that has the positive refraction focal power;
It is characterized in that described preceding camera lens part I all uses global face lens, comprises 5 lens, is docile and obedient preface from projecting into image planes, the 1st lens are a negative meniscus L 1, the 2nd lens are a falcate positive lens L 2, the 3rd lens are a negative meniscus L 3, the 4th lens are a negative meniscus L 4, the 5th lens are a double-concave negative lens L 5
The combined light focal power of camera lens part I satisfies following relation before described:
1.5f<| f Close|<2.5f, f Close<0
F wherein CloseBe the 1st lens L 1, the 2nd lens L 2, the 3rd lens L 3, the 4th lens L 4With the 5th lens L 5Combined focal length, f is the focal length of whole projection optical system;
Described rear lens part II comprises 9 lens, be docile and obedient preface begin after the camera lens part I in the past for: by the 6th lens L 6With the 7th lens L 7One group of cemented doublet with negative refraction focal power being formed is by the 8th lens L 8, the 9th lens L 9, the 10th lens L 10With by the 11st lens L 11, the 12nd lens L 12, the 13rd lens L 13Two groups that are formed have positive and negative positive three balsaming lenss of positive refraction focal power and lens the 14th lens L that a slice has the positive refraction focal power 14
2. the wide-angle projection optical system with long back of the body focal length comprises that one has the preceding camera lens part I of negative refraction focal power and the rear lens part II that has the positive refraction focal power;
It is characterized in that, described before camera lens part I used non-spherical lens, be docile and obedient preface and begin to be falcate aspheric surface negative lens L from projecting into image planes 1 ', a falcate positive lens L 2 ', a negative meniscus L 3 ', another negative meniscus L 4 '
The combined light focal power of camera lens part I satisfies following relation before described:
1.5f<|f (1’,2’,3’,4’)|<2.5f,f (1’,2’,3’,4’)<0
F wherein (1 ', 2 ', 3 ', 4 ')Be preceding camera lens L 1 ', L 2 ', L 3 ', L 4 'The combined focal length of camera lens;
Described rear lens part II comprises 9 lens, be docile and obedient preface begin after the camera lens part I in the past for: by the 6th lens L 6With the 7th lens L 7One group of cemented doublet with negative refraction focal power being formed is by the 8th lens L 8, the 9th lens L 9, the 10th lens L 10With by the 11st lens L 11, the 12nd lens L 12, the 13rd lens L 13Two groups that are formed have positive and negative positive three balsaming lenss of positive refraction focal power and lens the 14th lens L that a slice has the positive refraction focal power 14
3. the wide-angle projection optical system with long back of the body focal length comprises that one has the preceding camera lens part I of negative refraction focal power and the rear lens part II that has the positive refraction focal power;
It is characterized in that, described before camera lens part I used non-spherical lens, be docile and obedient preface and begin to be falcate aspheric surface negative lens L from projecting into image planes 1 ", a negative meniscus L 2 ", a negative meniscus L 3 "
The combined light focal power of camera lens part I satisfies following relation before described:
1.5f<|f (1”,2”,3”)|<2.5f,f (1”,2”,3”)<0
F wherein (1 ", 2 ", 3 ")Be preceding camera lens L 1 ", L 2 ", L 3 "The combined focal length of camera lens;
Described rear lens part II comprises 9 lens, be docile and obedient preface begin after the camera lens part I in the past for: by the 6th lens L 6With the 7th lens L 7One group of cemented doublet with negative refraction focal power being formed is by the 8th lens L 8, the 9th lens L 9, the 10th lens L 10With by the 11st lens L 11, the 12nd lens L 12, the 13rd lens L 13Two groups that are formed have positive and negative positive three balsaming lenss of positive refraction focal power and lens the 14th lens L that a slice has the positive refraction focal power 14
4. according to any one described wide-angle projection optical system among the claim 1-3, it is characterized in that described rear lens part II satisfies following relation with long back of the body focal length:
(2)|V 7-V 6|>20 (3)n 6>1.75
(4)n 8<1.55 (5)n 10<1.55
(6)n 11<1.55 (7)n 13<1.55
(8)n 14<1.55 (9)V 6<28
(10)V 8>60 (11)V 10>60
(12)V 11>60 (13)V 13>60
(14)V 14>60 (15)1.2<R 13/f<2.8
(16)1.0<R 15/f<2.6 (17)1.6<R 19/f<3.2
(18)3.5f<f back<4.8f
Wherein f is the focal length of whole projection optical system; f BackIt is the rear cut-off distance of described whole projection optical system; n 6, n 8, n 10, n 11, n 13, n 14Difference the 6th lens L 6, the 8th lens L 8, the 10th lens L 10, the 11st lens L 11, the 13rd lens L 13, the 14th lens L 14Refraction coefficient; V 6, V 7, V 8, V 10, V 11, V 13, V 14Be respectively the 6th lens L 6, the 8th lens L 8, the 10th lens L 10, the 11st lens L 11, the 13rd lens L 13, the 14th lens L 14Abbe constant; R 13Be the 7th lens L 7The radius of face shape; R 15Be the 8th lens L 8With the 9th lens L 9The radius of cemented surface; R 19Be the 11st lens L 11With the 12nd lens L 12The radius of cemented surface.
5. according to any one described wide-angle projection optical system among the claim 1-3, it is characterized in that, between first lens of the last a slice lens of preceding camera lens I and rear lens II, place the diaphragm sheet with long back of the body focal length.
6. according to any one described wide-angle projection optical system among the claim 1-3, it is characterized in that described projection optical system satisfies with long back of the body focal length | the requirement of u|<1 °, wherein u is the angle of visual field, edge chief ray and optical axis.
7. according to any one described wide-angle projection optical system among the claim 1-3, it is characterized in that described projection optical system satisfies 5f<D with long back of the body focal length 10The requirement of<10f, wherein, D 10Be the center of last a slice lens of camera lens I biconvex telescope direct L to camera lens II 6Spacing.
8. the wide-angle projection optical system with long back of the body focal length according to claim 7 is characterized in that, adds a slice reflective mirror M at last a slice lens of camera lens I between the biconvex telescope direct L6 of camera lens II, makes 90 °>θ of the optical axis anglec of rotation>45 °.
CN 03225024 2003-04-10 2003-04-10 Wide angle projection optical system possessing long back focal distance Expired - Lifetime CN2609005Y (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100429558C (en) * 2005-04-13 2008-10-29 普立尔科技股份有限公司 Projection optical system and its imaging module and imaging method
CN1969230B (en) * 2004-04-15 2010-05-05 富可视公司 Wide angle projection lens
CN114859524A (en) * 2022-07-07 2022-08-05 沂普光电(天津)有限公司 Ultra-short-focus optical system and projection equipment

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1969230B (en) * 2004-04-15 2010-05-05 富可视公司 Wide angle projection lens
CN100429558C (en) * 2005-04-13 2008-10-29 普立尔科技股份有限公司 Projection optical system and its imaging module and imaging method
CN114859524A (en) * 2022-07-07 2022-08-05 沂普光电(天津)有限公司 Ultra-short-focus optical system and projection equipment
CN114859524B (en) * 2022-07-07 2022-10-25 沂普光电(天津)有限公司 Ultra-short-focus optical system and projection equipment

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