CN1116315A - Three-group three-piece projection lens - Google Patents
Three-group three-piece projection lens Download PDFInfo
- Publication number
- CN1116315A CN1116315A CN 94108493 CN94108493A CN1116315A CN 1116315 A CN1116315 A CN 1116315A CN 94108493 CN94108493 CN 94108493 CN 94108493 A CN94108493 A CN 94108493A CN 1116315 A CN1116315 A CN 1116315A
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- lens
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- negative
- projection lens
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Abstract
Said lens consists of two positive lens and one negative len whose refractive index is Nd less than 1.52 and Abbe value more than 50. Said negative len is made of K or KF glass. The quality of large image projection by said invention is improved.
Description
The present invention relates to be used for the photo information of big picture is projected on the screen to obtain the three-group three-piece projection lens of the enlarged image similar to former photo information.The focal length model of camera lens is F=260-340mm.
Existing three-group three-piece projection lens generally all comprises picture frame, and place two positive lenss in the picture frame to reach between the middle negative lens of two positive lenss, this existing traditional three-group three-piece projection lens, positive lens is made by class optical glass such as QK, K, ZK, ZBaF, and negative lens is made by class optical glass such as QF, F, ZF, BaF.Determined by the projection lens environment for use, this class camera lens centering heart resolution requirement is not high, and the center and peripheral that requires picture has the image quality of mutual coupling, because having used class optical glass such as the less QF of Abbe number, F, ZF or BaF to make the positive lens that negative lens and Abbe number bigger QK, K, optical glass such as ZK, ZBaF make makes up, the surplus of axial chromatic aberration is very little, so little aberration residue is too little to the such optical system of projection lens, so that the design objective of aberration is wasted, increased the cost of camera lens undoubtedly; And make negative lens with this class glass, because refractive index is higher, be unfavorable for the curvature of field calibration of big visual field, the image quality of raising field of view edge, in order to proofread and correct the curvature of field, improve image quality, just have to improve the refractive index of positive lens glass or increase spacing between positive and negative lens, nature can make the cost of camera lens improve, and weight increases.So existing three-group three-piece projection lens cost is higher, weight lays particular stress on.
The objective of the invention is to the shortcoming higher at existing above-mentioned three-group three-piece projection lens cost, that weight lays particular stress on, provide that a kind of cost is lower, volume is little, lightweight three-group three-piece projection lens.
Three-group three-piece projection lens of the present invention, comprise a picture frame, in picture frame, set gradually positive lens 1, negative lens 2, positive lens 3 from front to back, between positive lens and negative lens, spacer ring is set, positive lens 3 rears are provided with trim ring, it is characterized in that described negative lens is by refractive index Nd＜1.52, the unusual negative lens that the optical glass of Abbe number Vd＞50 is made.
The present invention is owing to adopt class optical glass such as higher K of Abbe number or KF to make negative lens, though can cause the increase of the remaining axial chromatic aberration of camera lens, but the aberration amount that increases can not have influence on center resolution, because lens construction just--is being born--over against title, can not change ratio chromatism,, can not influence the center image quality of camera lens, and this class glass refraction is lower, helps correction, the raising field of view edge image quality of big visual field; And class such as K or KF, the glass price comparison is cheap, cost is low.Also can select for use the lower optical glass of refractive index to make positive lens or shorten spacing between positive and negative lens, thereby reduce the cost of projection lens, dwindle volume, alleviated weight.
In actual design, when making three-group three-piece projection lens of the present invention, from design considerations, method for making, the frame mode of camera lens is all continued to use the design considerations of existing three-group three-piece projection lens, frame mode and method for making, just owing in invention, adopt Vd＞50, the optical glass of Nd＜1.52 is made negative lens, so in design, when making the three-group three-piece camera lens, the Abbe number Vd of the material of requirement making positive lens is big as far as possible, preferably select K9 optical glass for use, in the aberration balancing process, axial chromatic aberration need be do not proofreaied and correct, but when correcting distorted, ratio chromatism, be taken into account.Because the bending of these three kinds of aberrations of spherical aberration, coma and the curvature of field and lens has confidential relation, the variation of spherical radius that makes full use of each lens is to the different interactivelies of these three kinds of aberrations, astigmatism, coma are proofreaied and correct, make its surplus as far as possible little, and spherical aberration will have suitable surplus, so that mate with the curvature of field of visual field, edge, makes the center and peripheral of picture that the respective imaging quality be arranged.
Refractive index Vd of the present invention＞50, the optical glass of Abbe number Nd＜1.52, in different countries different code names is arranged, be K, KF class for example in China, example K8, K9, K10, KF1, KF2, KF3 etc., as German SHOTT series BK7, K3, K4, K11, K51, K7 ... C, FF, K class optical glass in the Japan HOYA P series glass.
Fig. 1 is the structural representation of three-group three-piece projection lens of the present invention.
As shown in the figure, three-group three-piece projection lens of the present invention comprises a picture frame 4, sets gradually positive lens 1 in picture frame from front to back, and negative lens 2, positive lens 3 are provided with spacer ring 5 between positive lens 3 and the negative lens 2, at positive lens 3 rears one trim ring are set.
Fig. 2 a, 2b, 2c are respectively the positive lenss 1 of three-group three-piece projection lens of the present invention, the synoptic diagram of negative lens 2, positive lens 3.Wherein R1, R2 are respectively positive lenss 1, and the sphere curvature radius of former and later two polished surfaces of negative lens 2, positive lens 3, d1, d2, d3 are represented the center thickness of positive lens 1, negative lens 2, positive lens 3, the bore that D represents positive and negative lens respectively.D0 represents the effective aperture of a polished surface of negative lens 2.
Three-group three-piece eyeglass of the present invention recommends to select for use following material and data:
Nd Vd R1 R2 positive lens 1 1.5～1.6 55～70 48～52 95～115 negative lenses 2 1.49～1.52 50～64 210～240 56～72 positive lens 3 1.5～1.6 55～70 110～130 110～130 embodiment
A kind of focal length F=300mm, visual field 285 * 285mm, projector, filament is as the three-group three-piece projection lens of 42 * 42mm, wherein positive lens 1 is selected K9 class optical glass for use, convex surface radius R 1=51.171, concave R2=99.268, center thickness d1=10.5, bore D=φ 62 negative lenses 2 are selected K8 class optical glass for use, preceding concave R1=218.8 back concave surface radius R 2=58.882, center thickness d2=4, bore D= 62, preceding concave surface effective aperture D0= 60 positive lenss 3 are selected K9 class optical glass for use, convex front surface radius R 1=117.46, back convex surface radius R 2=122.46 center thickness d3=11.0, bore D= 60, positive lens 1 is 6.5 with the center distance of negative lens 2, need not with anti-circle, the external diameter of spacer ring 5 is all 62 mutually with the external diameter of lens, and interior garden circle surface diameter is 60, the garden surface thickness of spacer ring is 4.18mm, 45 ° of anti-circle front end face bevellings make anti-spacer ring except surface, interior garden, and remainder does not all contact with lens.
The endoporus of picture frame 4 directly matches with lens diameter, for 62 picture frame length are 33.5.
Example center resolution is greater than 121p/mm; 0.7 visual field resolution is greater than 61p/mm; Image planes center illumination is greater than 1200LX (plating chemical films); Coefficient of vignetting is greater than 75%.
Claims (1)
1. three-group three-piece projection lens, comprise a picture frame (4), in picture frame, set gradually positive lens (1), negative lens (2), positive lens (3) from front to back, spacer ring (5) is set between positive lens and negative lens, at positive lens (3) rear trim ring is set, it is characterized in that described negative lens is by refractive index Nd＜1.52, the unusual negative lens that the optical glass of Abbe number Vd＞50 is made.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 94108493 CN1116315A (en) | 1994-07-30 | 1994-07-30 | Three-group three-piece projection lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 94108493 CN1116315A (en) | 1994-07-30 | 1994-07-30 | Three-group three-piece projection lens |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1116315A true CN1116315A (en) | 1996-02-07 |
Family
ID=5033512
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 94108493 Pending CN1116315A (en) | 1994-07-30 | 1994-07-30 | Three-group three-piece projection lens |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1116315A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100465686C (en) * | 2005-09-30 | 2009-03-04 | 富士能株式会社 | Lens block, lens, holder for holding the lens block, and projector using the lens holder |
| CN101313240B (en) * | 2006-12-07 | 2010-06-23 | 里程碑株式会社 | Imaging lens |
| US7929223B2 (en) | 2005-09-30 | 2011-04-19 | Fujinon Corporation | Lens block, lens, holder for holding the lens block, and projector using the lens holder |
-
1994
- 1994-07-30 CN CN 94108493 patent/CN1116315A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100465686C (en) * | 2005-09-30 | 2009-03-04 | 富士能株式会社 | Lens block, lens, holder for holding the lens block, and projector using the lens holder |
| US7929223B2 (en) | 2005-09-30 | 2011-04-19 | Fujinon Corporation | Lens block, lens, holder for holding the lens block, and projector using the lens holder |
| CN101313240B (en) * | 2006-12-07 | 2010-06-23 | 里程碑株式会社 | Imaging lens |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |