GB2138591A - Infrared Objective Zoom Lens Assembly - Google Patents
Infrared Objective Zoom Lens Assembly Download PDFInfo
- Publication number
- GB2138591A GB2138591A GB08407101A GB8407101A GB2138591A GB 2138591 A GB2138591 A GB 2138591A GB 08407101 A GB08407101 A GB 08407101A GB 8407101 A GB8407101 A GB 8407101A GB 2138591 A GB2138591 A GB 2138591A
- Authority
- GB
- United Kingdom
- Prior art keywords
- zoom
- component
- assembly
- collecting
- lens
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 claims description 20
- 230000005855 radiation Effects 0.000 claims description 9
- 210000001747 pupil Anatomy 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 230000015556 catabolic process Effects 0.000 description 4
- 238000006731 degradation reaction Methods 0.000 description 4
- 229910052732 germanium Inorganic materials 0.000 description 4
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 4
- 239000000969 carrier Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- LYQFWZFBNBDLEO-UHFFFAOYSA-M caesium bromide Chemical compound [Br-].[Cs+] LYQFWZFBNBDLEO-UHFFFAOYSA-M 0.000 description 2
- SBIBMFFZSBJNJF-UHFFFAOYSA-N selenium;zinc Chemical compound [Se]=[Zn] SBIBMFFZSBJNJF-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- PGAPATLGJSQQBU-UHFFFAOYSA-M thallium(i) bromide Chemical compound [Tl]Br PGAPATLGJSQQBU-UHFFFAOYSA-M 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/14—Optical objectives specially designed for the purposes specified below for use with infrared or ultraviolet radiation
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
- G02B15/1435—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative
- G02B15/143503—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative arranged -+-
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Telescopes (AREA)
Abstract
A refractor-type infrared telescope (20) incorporates an eyepiece system (24) aligned on a common axis (21) with an objective lens assembly (22, 23) formed by a zoom system (22) at least one of whose surfaces is aspheric, and a collecting system (23). Collecting system (23) is formed by a single fixed lens element D optionally having an aspheric refractive surface (7). Zoom system (22) is formed by a first movable component (lens element E) mounted on carriage (26), a second movable component (lens elements F, G) mounted on carriage (25) and a fixed third component (lens element H). Optionally lens elements (E, F, and H) incorporate respective refractive surfaces (9, 11 and 15) which are aspheric. <IMAGE>
Description
SPECIFICATION
Infrared Objective Lens Assembly
This invention relates to an infrared objective lens assembly.
The arrival of high performance infrared radiation detecting systems has led to a demand for high performance lens assemblies which for some applications require several alternative fields of view with continuity of imaging (i.e. zooming) during a field of view change. Further requirements are compactness (i.e. short overall length), mechanical and optical simplicity, image resolution throughout the range of fields of view and a relatively large zoom ratio.
It is therefore an object of the present invention to provide an improved form of infrared objective lens assembly which is of high performance, is of variable field of view and is compact.
According to the present invention there is provided an infrared objective lens assembly comprising a three-component zoom system aligned with a one-component collecting system on a common optical axis, said zoom system being arranged to accept from object space radiation in the infrared waveband and the collecting system being arranged to form a real image from radiation delivered thereto by said zoom system, the components of said zoom and collecting systems being formed by lens elements, at least one of said zoom-system lens elements having an aspheric refractive surface, and wherein with respect to said collecting system the first and second components of said zoom system are mounted on respective carriages and are separately selectively positionable along said optical axis, and the third component of said zoom system is fixedly positioned on said optical axis whereby said zoom system is mechanically compensated and of variable effective focal length.
Preferably said first and third zoom-system components each have positive optical power and said second zoom-system component has negative optical power.
Conveniently each component of said zoom and collecting systems is formed by a single lens element.
The assembly of the present invention is optically and mechanically simple and at the same time is rendered compact by the use of at least one aspheric refractive surface in the zoom system. The assembly may also be easily colour-corrected by selection of materials. For example oil lens elements may be made of germanium except for a lens element in the second zoom-system component which may be made from any of the materials listed in Table Ill.
An embodiment of the present invention will now be described by way of example with reference to the accompanying schematic drawing and tables.
The schematic drawing illustrates a variable magnification telescope 20 formed by an objective lens assembly 22, 23 according to the present invention and an eyepiece system 24. The objective lens assembly comprises a zoom system 22 and a collecting system 23, systems 22, 23 and 24 being aligned on a common optical axis 21.Radiation from object space 18 is directed by the objective lens assembly 22, 23 to form a real image 1 7 from which eyepiece system 24 relays the radiation to image space 19 via a pupil . The magnification factor of the telescope 20 is within the range xl to x9 and the drawing illustrates four separate magnification factors individually in the interests of clarity since each specific magnification factor is determined by specific positioning of the movable components of the zoom system 22 axially along axis 21.
The collecting system 23 is formed by a single lens element D fixedly positioned on the optical axis 21 and having refractive surfaces 7, 8. The zoom system 22 is formed by three components of which the first component (with respect to the collecting system 23) is formed by a single lens element
E, the second component is formed by a pair of lens elements G, F forming a doublet and the third component is formed by a single lens element H. Lens elements E, F, G and H have respective refractive surface pairs 9, 10; 11, 12; 13, 14; 1 5, 16, and element H is fixedly located on the axis 21 but elements E, F and G are movable along the axis 21 to provide the zoom effect as will be explained.The eyepiece system 24 is formed by three lens elements A, B, C forming a triplet with respective refractive surface pairs 1,2; 3,4; 5,6 and is fixedly located on the optical axis 21.
In order to provide the variable magnification for the telescope 20 the first and second components of the zoom system 22 are each mounted on respective separate carriages 25 and 26 for axial movement along the optical axis 21 within the physical limits imposed by the presence of the third component of system 22 (lens element H) and the collecting system 23 (lens element D) which are fixedly located on the optical axis 21. In order to provide focus compensation for thermal effects an adjustment in position may conveniently be made to at least one of the carriages 25 and 26.
Zoom system 22 is provided with refractive surfaces 9-1 6 of which surfaces 7, 9, 11 and 1 5 are aspheric, the others being either spherical or planar. This makes system 22 have a small number of lens elements and the presence of aspheric surfaces 7, 9, 11 and 1 5 makes system 22 compact with a large variable range of fields of view (or magnifications). The aspheric surfaces 7, 9, 11 and 1 5 have their profiles governed by the known aspheric equation:
where
Z=distance parallel to the optical axis
C=inverse of the radius of curvature of the datum spherical surface
H=radial distance perpendicular to optical axis.
and in the case of surface 7 C=1/(-86.99 mm) 8=--5.31x10-7 G and D=zero and
H has a maximum value of 26.97 and in the case of surface 9 C=1/(-442.77 mm) B=--1.97x10-7 G and D=zero and
H has a maximum value of 27.50 mm and in the case of surface 11 C=1/(-147.59 mm)
B=+7.62x 10-7
G and D=zero and
H has a maximum value of 22.35 mm and in the case of surface 1 5 C=1/(-1 90.55 mm) B=+2.41 x 10-9 G=-7.74x 10-'3 D=+7.41 x 10-17 and
H has a maximum value of 68.64 mm.
The remaining parameter values of the telescope 20 are given in Table I.
It will be noted that the four aspheric surfaces 7,9,11, 5 have a small to medium degree of asphericity, the maximum departure from a best fit sphere being 35 micrometers in the case of surface 7, which is conducive to current manufacturing methods such as diamond point turning and is just acceptable for the more traditional method of petal lap polishing.
The performance values for the telescope 20 having the Table I parameters are set forth in Table
II for each of four magnification factors from which it can be seen that the telescope is of high performance (i.e. near diffraction limited) over at least two-thirds of the field of view and is extremely compact.
The effective focal length (EFL) is denoted in the drawing for each magnification factor and illustrates that an increase in effective focal length from the minimum effective focal length is produced by separate movements of carriages 25 and 26 towards the collecting system 23, carriage 26 reversing direction at an intervening effective focal length (x3.67 magnification) so that the maximum effective focal length is produced when the carriages 25 and 26 approach each other and are limited by abutment. The locus of movement of carriage 25 is depicted by numeral 29 and that of carriage 26 by numeral 30.
As regards the optical powers of the lens elements of the zoom system 22 and the collecting system 23, elements H, E and D are each positively powered, G and F as a component is negatively powered and each of G and F is negatively powered. Because of the materials used to form the lens elements as set forth in Table I the telescope 20 accepts radiation in the 8-1 3 micrometer waveband and by virtue of the numeric values has a focus in the range 50 meters to infinity with minimal degradation of resolution, but if such degradation is acceptable focus down to 20 meters can be achieved. The telescope 20 is also athermalised over the range --100C to +500C with minimal degradation in overall performance.For practical purposes if the resolution degradation is acceptable the range for thermal compensation can be increased to -400C to +90oC but the telescope 20 displays transmission loss due to absorption of radiation by the germanium at the high temperature end of the range. The aperture diameter of the largest element of the zoom system is enlarged by less than 4% to accommodate pupil aberrations.
The zoom system 22 detailed in Tables I and it may be scaled and optimised to provide a wide
range of upper and lower effective focal lengths and magnification factors and if the largest
magnification factor is sufficiently low, colour-correction may not be required in which case all lens
components may be made of the same material such as germanium. It is also possible to optimise the
eyepiece system 24 and collecting system 23 in such a way as to provide a different field of view and
pupil diameter in image space thus making the telescope suitable for attachment to different detector
systems which may or may not use scanning mechanisms.
It will be appreciated that each aspheric surfaced lens element can be replaced with two
spherically surfaced lens elements without changing the component form of the lens. However, this
increases the number of lens elements by four which for telescope 20 results in an undesirable
increase in length and weight, an undesirable decrease in transmission and a general increase in
mechanical and optical complexity. Because of the relatively high cost of germanium the replacement of aspheric surfaces by lens elements made from such a preferred material will probably also increase the cost.
It will also be appreciated that to maintain a short overall length of telescope 20 as shown in the drawing, the f-number at the internal real image 1 7 should be kept small e.g. less than 2.0, which entails the use of at least one aspheric surfaced lens element or two spherically surfaced lens elements in the collecting system 23. Furthermore, where a lens element has a single aspheric refractive surface as previously set forth the aspheric surface may be the other refractive surface of the pair or alternatively both refractive surfaces of the element may be aspheric such that the overall effect remains the same.
It will be appreciated that the telescope 20 of the embodiment is optimised for focus on an object close to infinity and that change in the field of view (magnification) by movement of the carriages 25 and 26 can maintain the nominal focus. However, for an object at a distance other than infinity the telescope 20 requires to be focussed initially and this is conveniently achieved by movement of at least one of carriers 25 and 26. In each case after the initial focussing, according to the distance of the object, at least one of the carriers 25 and 26 may be moved within the physical space constraints for refocussing of the image in compensation of temperature variations and zoom system movements.
All data recited herein and in the tables is for a temperature of 200C and as regards Table Ill the
V-values given are calculated from the standard formula
refractive index at 10 micrometers--l.0 V=
refractive index at 8.5 micrometers-refractive index at 11.5 micrometers and the f-number specified herein is derived from the formula (2 sin )-1 where 4 is the half angle of the cone formed by the axial pencil after refraction from the lens element on which the pencil is incident.
By virtue of the fact that carriers 25, 26 are physically separate and with individual mechanical drives it is possible to use the zoom system 22 in a dual-magnification mode only. In this case carriage 26 is fixedly located and carriage 25 is selectively located in one or other of the two compatible positions which provide the resolution previously referred to. This arrangement of course does not provide continuous focus between magnifications but is mechanically simple having only one moving component and can provide a very large magnification ratio such as 9:1.
TABLE I
Maximum
Radius of Aperture
Lens Surface Separation Magnification Curvature Material Diameter Pupil* # 0 any Flat Air 15.30 1 21.57 any -91.41 Air 33.79
A
2 3.75 any -61.72 Ge 35.15
3 0.50 any -187.37 Air 35.56
B
4 3.50 any -113.90 Ge 36.12
5 0.50 any 31.48 Air 34.65
C
6 10.32 any 26.84 Ge 26.08 7'# 58.80 any -86.99 Air 53.95 D
8 6.25 any -59.08 Ge 56.55 # 34.59 x1.00 1.46 x3.67
E 9' -442.77 Air 55.00
12.63 x6.33
27.26 x9.00 10 5.00 any -154.59 Ge 55.20 # 59.52 x 1.00 41.15 x3.67
F 11 -147.59 Air 44.70
22.72 x6.33
5.32 x9.00
12 3.50 any 164.73 Ge 44.71
13 5.50 any -114.57 Air 46.24
G
14 3.00 any -237.10 ZnSe 48.78 # 11.18 x 1.00 62.68 x3.67
H 15' -190.55 Air 137.28
69.94 x6.33
72.71 x9.00
16 14.50 any -131.09 Ge 142.95
*Maximum field angle at pupil=46.40.
& um;Surfaces 7',9',11' and 15' have aspheric profiles.
TABLE II
Approximate R.M.S. Spot Sizes in Object Space *(Milliradians Monochromatic at Polychromatic over # 10.0 micrometers 8.5-11.5 micrometers Magnification Field position as a fraction of the full field at pupil & um; 0 0.4 0.8 0 0.4 0.8 x1.00 1.331 1.195 1.366 1.429 1.354 1.684 x3.67 0.007 0.192 0.515 0.112 0.212 0.525 x6.33 0.183 0.226 0.302 0.190 0.233 0.311 x9.00 0.103 0.079 0.157 0.124 0.109 0.182 *Pupil diameter=14.4 mm.
Given as an equally weighted three wavelength accumulated measurement, the wavelengths being 8.5, 10.0 and 11.5 micrometers.
#Maximum field angle at pupil=46.40.
TABLE Ill
Material Refractive Index* V-value# BS2 2.85632 248 BSA 2.77917 209 TI 1173 2.60010 142 ASTIR 1 2.49745 169 BS1 2.49158 152 Tl20 2.49126 144 ZnSe 2.40653 77 KRS 5 2.37044 260 Csl 1.73933 316 CsBr 1.66251 176 K 1.62023 137 *Refractive index is for a wavelength of 10 micrometers.
# Over the wavelength range 8.5-11.5 micrometers.
Claims (8)
1. An infrared objective lens assembly comprising a three-component zoom system aligned with a one-component collecting system on a common optical axis, said zoom system being arranged to accept from object space radiation in the infrared waveband and the collecting system being arranged to form a real image from radiation delivered thereto by said zoom system, the components of said zoom and collecting systems being formed by lens elements, at least one of said zoom-system lens elements having an aspheric refractive'surface, and wherein with respect to said collecting system the first and second components of said zoom system are mounted on respective carriages and are separately selectively positionable along said optical axis, and the third component of said zoom system is fixedly positioned on said optical axis whereby said zoom system is mechanically compensated and of variable effective focal lehgth.
2. An assembly as claimed in claim 1 , wherein each of said first and second zoom system components comprises a lens element having an aspheric refractive surface.
3. An assembly as claimed in claim 1 or claim 2, wherein each component of said zoom and collecting systems is formed by a single lens element.
4. An assembly as claimed in any preceding claim, wherein said first and third zoom-system components each have positive optical power and said second zoom-system component has negative optical power.
5. An assembly as claimed in claim 1, wherein said first zoom component is positively powered and said second zoom component is negatively powered.
6. An assembly as claimed in any preceding claim, wherein the f-number at said internal real image is less than 2.0.
7. An assembly as claimed in claim 1, and as set forth in Table I.
8. An infrared objective lens assembly as claimed in claim 1 and substantially as hereinbefore described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08407101A GB2138591B (en) | 1983-04-16 | 1984-03-19 | Infrared objective zoom lens assembly |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8310364 | 1983-04-16 | ||
| GB08407101A GB2138591B (en) | 1983-04-16 | 1984-03-19 | Infrared objective zoom lens assembly |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2138591A true GB2138591A (en) | 1984-10-24 |
| GB2138591B GB2138591B (en) | 1986-05-08 |
Family
ID=26285847
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08407101A Expired GB2138591B (en) | 1983-04-16 | 1984-03-19 | Infrared objective zoom lens assembly |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2138591B (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2159297A (en) * | 1984-05-22 | 1985-11-27 | Bar & Stroud Limited | Infrared afocal refractor telescope |
| FR2564990A1 (en) * | 1984-05-22 | 1985-11-29 | Barr & Stroud Ltd | INFRARED AFOCAL EYEGLASS |
| GB2194072A (en) * | 1986-04-03 | 1988-02-24 | Pilkington Perkin Elmer Ltd | Athermalised optical beam expander |
| FR2643156A1 (en) * | 1989-02-15 | 1990-08-17 | Electro Optics Ind Ltd | VARIABLE FOCAL REMOTE OBJECTIVE FOR INFRARED TEMPERATURE COMPENSATION |
| EP0457493A1 (en) * | 1990-05-18 | 1991-11-21 | Gec-Marconi Avionics (Holdings) Limited | Zoom lens |
| EP0539914A1 (en) * | 1991-10-30 | 1993-05-05 | Firma Carl Zeiss | Afocal zoom lens system with achromatic and athermal behaviour in the infrared wavelength region |
| EP0848273A2 (en) * | 1996-12-11 | 1998-06-17 | HE HOLDINGS, INC. dba HUGHES ELECTRONICS | Conformal window design with static and dynamic aberration correction |
| WO2011025850A1 (en) * | 2009-08-28 | 2011-03-03 | Corning Incorporated | Mid infrared spectral band continuous zoom system |
| CN110133832A (en) * | 2019-04-03 | 2019-08-16 | 中国科学院西安光学精密机械研究所 | A kind of wavefront coded infrared no thermalization continuous magnification lens |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2126370A (en) * | 1982-09-04 | 1984-03-21 | Pilkington Perkin Elmer Ltd | Infra-red objective zoom lenses |
-
1984
- 1984-03-19 GB GB08407101A patent/GB2138591B/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2126370A (en) * | 1982-09-04 | 1984-03-21 | Pilkington Perkin Elmer Ltd | Infra-red objective zoom lenses |
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2564990A1 (en) * | 1984-05-22 | 1985-11-29 | Barr & Stroud Ltd | INFRARED AFOCAL EYEGLASS |
| GB2159297A (en) * | 1984-05-22 | 1985-11-27 | Bar & Stroud Limited | Infrared afocal refractor telescope |
| GB2194072A (en) * | 1986-04-03 | 1988-02-24 | Pilkington Perkin Elmer Ltd | Athermalised optical beam expander |
| US4834472A (en) * | 1986-04-03 | 1989-05-30 | Pilkington P.E. Limited | Optical beam expanders with materials chosen to effect athermalization |
| GB2194072B (en) * | 1986-04-03 | 1990-03-21 | Pilkington Perkin Elmer Ltd | Athermalised optical beam expander |
| GB2228343B (en) * | 1989-02-15 | 1993-05-19 | Electro Optics Ind Ltd | Zoom system |
| FR2643156A1 (en) * | 1989-02-15 | 1990-08-17 | Electro Optics Ind Ltd | VARIABLE FOCAL REMOTE OBJECTIVE FOR INFRARED TEMPERATURE COMPENSATION |
| GB2228343A (en) * | 1989-02-15 | 1990-08-22 | Electro Optics Ind Ltd | Zoom system |
| EP0457493A1 (en) * | 1990-05-18 | 1991-11-21 | Gec-Marconi Avionics (Holdings) Limited | Zoom lens |
| EP0539914A1 (en) * | 1991-10-30 | 1993-05-05 | Firma Carl Zeiss | Afocal zoom lens system with achromatic and athermal behaviour in the infrared wavelength region |
| EP0848273A2 (en) * | 1996-12-11 | 1998-06-17 | HE HOLDINGS, INC. dba HUGHES ELECTRONICS | Conformal window design with static and dynamic aberration correction |
| EP0848273A3 (en) * | 1996-12-11 | 1998-12-30 | Raytheon Company | Conformal window design with static and dynamic aberration correction |
| US6018424A (en) * | 1996-12-11 | 2000-01-25 | Raytheon Company | Conformal window design with static and dynamic aberration correction |
| WO2011025850A1 (en) * | 2009-08-28 | 2011-03-03 | Corning Incorporated | Mid infrared spectral band continuous zoom system |
| US7961382B2 (en) | 2009-08-28 | 2011-06-14 | Corning Incorporated | Mid infrared spectral band continuous zoom system |
| CN110133832A (en) * | 2019-04-03 | 2019-08-16 | 中国科学院西安光学精密机械研究所 | A kind of wavefront coded infrared no thermalization continuous magnification lens |
| CN110133832B (en) * | 2019-04-03 | 2024-05-31 | 中国科学院西安光学精密机械研究所 | Wavefront coding infrared athermalized continuous zoom lens |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2138591B (en) | 1986-05-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4971428A (en) | Catadioptric zoom lens | |
| JP2524612B2 (en) | Infrared Afocal Zoom Telescope | |
| US4249793A (en) | Erect type zoom telescopic optical system | |
| US4679891A (en) | Infra-red lenses | |
| US4469396A (en) | Afocal dual magnification refractor telescopes | |
| EP0367197A2 (en) | Dual band/dual FOV infrared telescope | |
| US4632498A (en) | Variable magnification infrared objective lens assembly | |
| JPS6127723B2 (en) | ||
| EP0365208A2 (en) | Wide band color correcting infrared lens system | |
| US4397520A (en) | Afocal refractor telescopes | |
| US4411488A (en) | Afocal zoom refractor telescopes | |
| US5548439A (en) | Three field of view refractive infrared telescope with fixed medium filed of view | |
| US4505535A (en) | Infrared objective lens systems | |
| US4479695A (en) | Afocal refractor telescopes | |
| US4659171A (en) | Infrared afocal refractor telescope | |
| US4278330A (en) | Catadioptric virtual-zoom optical system | |
| GB2138591A (en) | Infrared Objective Zoom Lens Assembly | |
| US4398786A (en) | Collimation lens system | |
| US5022724A (en) | Zoom system | |
| US4676581A (en) | Infra-red lenses | |
| GB2136149A (en) | High Magnification Afocal Infrared Telescopes | |
| EP0457493A1 (en) | Zoom lens | |
| US4558222A (en) | Infrared radiation detecting systems | |
| US4768869A (en) | Catadioptric imaging system | |
| JP2737272B2 (en) | Variable power optical system for infrared |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20000319 |