Abstract:
An objective comprising axial symmetry, at least one curved mirror and at least one lens and two intermediate images. The objective includes two refractive partial objectives and one catadioptric partial objective. The objective includes a first partial objective, a first intermediate a image, a second partial objective, a second intermediate image, and a third partial objective. At least one of the partial objectives is purely refractive. One of the partial objectives is purely refractive and one is purely catoptric.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The invention is related to a catadioptric objective comprising two intermediate images. 
     TECHNICAL FIELD 
     Such is known from U.S. Pat. No. 4,701,035 to Hirose as a microlithographic projection exposure system. The objective shown there in FIG. 12 comprises two catoptric partial objectives and one catadioptric partial objective. All objectives are off-axis, not axially symmetric, purely spherical systems. 
     Catadioptric objectives with one intermediate image and a refractive partial objective are known as microlithographic projection systems with axial symmetry and central 09/263,788) to Schuster, the latter being assigned to the assignee of this invention, and incorporated herein by reference. 
     Elliott and Shafer show the intermediate image near to the central opening of one of the mirrors, and lenses are arranged in the light path between the mirrors forming Mangin mirrors. All their optical surfaces are spherical. 
     Schuster shows only the mirrors to be aspherical and avoids big lenses in the beam path between them. 
     U.S. Pat. No. 5,004,331 to Haseltine et al. discloses a catadioptric projector for projecting an image to a dome (of a flight simulator). The system comprises an external entrance pupil as means for receiving substantially collimated light, a refractive subsystem of rotationally symmetric, coaxial lenses forming a pupil image which is situated at the central opening of an aspheric concave mirror, which together with another concave mirror forms a reflective pupil relay system. Both mirrors are tilted with respect to the optical axis of the refractive subsystem. The whole system provides a wide field of view image on a spherical dome. Full visible spectrum colour correction is obtained by combination of different glass. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide new design alternatives which allow for high resolution objectives with reduced lens diameters and high performance. Advantageously these designs are to be used in the VUV spectral region for microscopy or microlithography. 
     The solution of this problem is obtained by an objective comprising axial symmetry, at least one curved mirror and at least one lens and two intermediate images. The objective includes two refractive partial objectives and one catadioptric partial objective. The objective includes a first partial objective, a first intermediate image, a second partial objective, a second intermediate image, and a third partial objective. At least one of said partial objectives is purely refractive. One of the partial objectives is purely refractive and one is purely catoptric. 
     Axial symmetry together with two intermediate images, two refractive and one catadioptric partial objectives, two intermediate images and at least one refractive partial objective are varied descriptions of the novel aspects of the invention. 
     Another aspect that clearly groups the mirrors in one catoptric partial objective, which cooperates with one or more purely refractive partial objectives. In this case it is provided that the catoptric partial objective carries the burden of Petzval sum reduction or field flattening. This relieves the refractive partial objective from the need for beam contractions and expansions by negative and positive lens groups, as is long established with microlithographic projection exposure lenses, see e. g. Glatzel E., ZEISS-Information 26 (1981), p. 8-13, U.S. Pat. No. 5,260,832 or U.S. Pat. No. 5,903,400. In consequence the refractive partial objective is simplified and the lens diameters are reduced. Especially for the proposed use in the VUV spectral region this gives great relief to the materials supply of suitable crystals or quartz glasses. 
     The preferred embodiments also are related to the cited Schuster or Elliott and Shafer designs with two coaxial central obscuration opposing convex mirrors, which allows for a very convenient axial symmetric construction of the objective. Such inter alia has advantages in mechanical rigidity and in compatibility with established stepper/scanner architectures adapted to refractive objectives. 
     As a central obscuration in principle has degenerating effects in imaging—though in many cases decidedly taken advantage of as in annular or quadrupole illumination or in pupil filtering and apodisation—the reduction of the obscuration by the central hole of the mirrors of this design is of importance. 
     A preferred way of reducing obscuration is achieved by placing the intermediate images in the vicinity of the mirrors. 
     In an alternative embodiment, lenses are inserted between the mirrors. As negative lenses these cooperate with the mirrors to give single material colour correction, relieving the need for band narrowing the laser light source or for using an achromatizing material pair in the VUV. 
     The chief ray height at each of the mirror bores is approximately the same in value, but opposite in sign. This measure allows for minimal central obscuration. 
     The sequence where the mirror-containing partial objective is framed by the two refractive partial objectives is preferred as it allows for both intermediate image “planes” connected by the mirror containing partial objective to be curved such as to best exploit the specific correction capabilities of this partial objective. 
     While it is rather conventional that mirrors are aspheric also in the related art, in the present invention it is specifically stated that aspheric lens surfaces prove advantageous with this design. All advantages and restrictions as recently established for refractive projection exposure objectives, see e. g. patent application DE 199 22 209 of Schuster and references cited therein, as incorporated herein by reference, hold also for the use of aspheric surfaces in the designs of this invention. 
     Diffractive surfaces, as occasionally also proposed for projection exposure objectives, are also useful with this invention just as they are with refractive designs. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in more detail based on the examples shown in the drawings. 
     FIG. 1 shows the lens section of an example of an objective with a refractive, a catadioptric, a second refractive partial objective in sequence, reduction ratio 1:6. 
     FIG. 2 shows another example of such an objective with reduction ratio 1:5. 
     FIG. 3 shows a schematic lens arrangement of an objective with a purely catoptric partial objective of axial symmetry. 
     FIG. 4 shows another example of the invention with a refractive, a catoptric, a second refractive partial objective in sequence. 
     FIG. 5 shows schematically a microscope with an objective according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The example of FIG. 1 is a 6:1 reduction objective for a scanner projection exposure apparatus of microlithography, with an image field diameter of 18.4 mm, an image side NA=0.75, being telecentric in the object space and the image space. 
     All lenses are made of fluorite CaF 2  and the system is adapted for illumination by the F 2  excimer-laser at 157 mm. 
     Certainly modifications for other wavelengths with other materials are possible, e. g. 193 nm and quartz glass. 
     The first partial objective S 1  is refractive and has a reduction ratio of−1/4,27. 
     It shows two distinct lens groups LG 1  of four relatively big lenses of about 130 mm diameter, and after the aperture plane a second lens group LG 2  with significantly reduced diameter of about 80 mm and less. Here, the only aspheric lens surface is provided on surface  9  immediately subsequent to the aperture plane. Subsequent to the first intermediate image IMI  1 , the second partial objective S 2  is catadioptric with two opposite concave aspheric mirrors M 1 , M 2  with central holes and two negative meniscus lenses  25 ,  26  and  27 ,  28  arranged between them. They are passed by the light beams three times. Its magnification ratio is −1/0,99. 
     Such a magnification ratio near unity allows for a highly symmetric construction and optimal correction of distortions. 
     This arrangement is particularly suitable for chromatic correction and correction of field curvature, too. Therefore even with only one lens material CaF 2  a relatively wide laser bandwith of +−1.2 pm of an unnarrowed F 2 -laser is accepted by this objective. 
     Subsequent to the second intermediate image IM 12  the third partial objective S 3  again is refractive. 
     It takes up the divergent light beam with a strongly bent meniscus  29 , 30 . A positive air lens—i. e. an air space in the form of a positive lens—between the lens surfaces  40  and  41  is characteristic. 
     With its reduction ratio of −1/1,42 the overall reduction ratio of the system is reached. 
     The detailed data of Table 1 show that the objective is composed of relatively few elements of limited diameters which helps for practical feasibility, as CaF 2  is very expensive and of limited availability. Also the light path in CaF2 is limited, thus reducing the problem of significant absorption at 157 mm. 
     The central obscuration necessitated by the fully coaxial construction of the catadioptric second partial objective S 2  is a certain drawback, as such in principle deteriorates the modulation transfer function of an objective. 
     However, even in common refractive projection exposure objectives a small but distinct central obscuration is entered to accomodate beam paths of alignment systems etc. 
     Efforts are taken in the design to keep the central obscuration small, even with mirror diameters of practical size. 
     It was found that the diameter of the holes in the mirrors is minimized when the chief ray height is of equal value at the two holes, but opposite in sign. 
     Further the mirror holes are arranged next to the two intermediate images IMI  1  and IMI  2 , where the beam diameters are at a minimum. Also the first partial objective S 1  has substantial image reduction to keep this hole absolutely small, so that also the total mirror diameter is limited to a practical compact value. 
     The mirror holes are sized to be 2,0 mm larger in diameter than the closest ray at the edge of the field. 
     It is recommended that a obscuration mask is inserted at the pupil (aperture) plane of the second partial objective S 2 —just in front of lens surface  9 . This should be sized 20,25% in diameter—equal to 4,1% in area. Then the area obscuration at the edge of the field has the same value as at the center and the MTF curves are completely uniform over the field. 
     The wavefront correction of this example is better than 0,011 waves rms over the field of 17×7 mm 2  and less than 0,009 waves rms over the field of 17×6 mm 2 . The distortion is 2.4 ppm and the median shift is 10 nm. 
     Colour correction reaches CHL=34 nm/pm for longitudinal colour, so that a+−1.2 pm bandwidth of an unnarrowed F 2 -laser can be accepted. 
     The example of FIG.  2  and table 2 has an increased image field of 22×9 mm 2  as well as a significantly increased NA=0,75, while the reduction ratio is changed to 5:1. The system is of overall similarity with the first example, but with some significant deviations. 
     The first refractive partial objective S 1  has its aperture plane enclosed by two menisci  209 ,  210  and  211 ,  212  which are concave towards the aperture plane. Here, an obscuring disk OD is inserted for the purpose of field-independent obscuration as described above. 
     Two lens surfaces  209  and  217  are aspheric, the first is next to the aperture plane to affect angle deviations and the second is more in the field region. 
     The imaging ratio of the first partial objective S 1  is −1/4,67. Therefore the catadioptric partial objective can be so small. 
     The second partial objective S 2  again is catadioptric with two aspheric mirrors M 21 , M 22  and two negative meniscus lenses  223 , 224  and  225 , 226 . Now their distance has strongly decreased, but angles increased in the beam path. This allows for very limited diameters of only 230 mm at the given large field and large NA. The reduction ratio is —1//0,97. In this embodiment, too, the central obscuration is  20 % in diameter constant over the full field. 
     High NA of 0,7 at the intermediate images to allow for the small holes in the mirrors M 21 , M 22  and a rather strong refractive power of the lenses  223 , 224  and  225 , 226  in between to give the required colour correction are specific to this example. 
     The mirrors M 21 , M 22  are aspheric with maximum deviations from sphere being limited to 150 micrometers, which allows for good production and testing. 
     Also on the lenses between the mirrors aspheric surfaces could increase image quality. A third negative lens here would further optimize colour correction, if needed. 
     The third partial objective S 3  shows the characteristic first meniscus lens  227 , 228  to be even more bent than in FIG.  1 . This helps for coma correction. Also the second lens  229 , 230  is a meniscus concave on the intermediate image IMI side, as the two final lenses  249 , 250  and  251 , 252  are menisci concave towards the image plane Im, what is preferred for aplanatism and correction of spherical aberration. 
     The positive air lens arranged between the lens surfaces  238  and  239  corrects the main part of spherical aberration. For this effect it is preferably arranged more in the pupil region of the objective than in a field region. However its arrangement before the pupil plane enables it to affect also the oblique spherical aberration in tangential and sagittal direction. 
     As a meniscus concave toward the pupil plane, lens  245 , 246  together with the air space created in front of it assists to the effects of the aforementioned air space. 
     The imaging ratio of this third partial objective S 23  is −1/1,11 near unity. However, the arrangement is far from symmetry to the pupil plane, so that the strongly distorted intermediate image IMI can be transformed to a highly corrected image at the image plane Im. 
     Each partial objective has its part of the burden: S 21  performs the reduction, S 22  makes the colour and Petzval correction and S 23  makes the fine tuning of imaging errors. 
     This second embodiment is not finely tuned to best error correction, but gives the principles of feasibility of such a design. 
     The aspheric surfaces of both examples of tables 1 and 2 are described by 
     
       
           z =AS 2 × h   4 +AS 3 × h   6 +AS 4 × h   8 +AS 5 × h    10 +AS 6 × h   12 =AS 7 × h   10   
       
     
     with z=axial deviation from sphere, h=radial height from optical axis. 
     The example of FIG. 3 has a purely catoptric partial objective S 31  and a purely refractive partial objective S 32  between object Ob and image Im, with intermediate image IMI. This avoids the big negative lenses f the catadioptric partial objectives of the aforementioned examples. The mirrors M 1 , M 2  now are purely used for Petzval correction—correction of field curvature. 
     The chromatic characteristics of the objective are defined by the refractive partial objective S 32 . Use of different lens materials allows for achromatization. For DUV/VUV excimer laser systems combinations of fluorides, namely calcium fluoride (fluorspar, fluorite), barium fluoride, strontium fluoride, NaF, Lif etc. and/or quartz glass, also in specifically doped versions, are adequate. Thus, for microlithography at 157 nm, positive lenses L 1 ,L 3  can be made of calcium fluoride and negative lens L 2  can be made of barium fluoride or NaF, for example. 
     Naturally the refractive partial objective S 32  has more lenses in a realistic microlithography or microscope objective and the lenses L 1  to L 3  shown are only schematic representatives. 
     As the refractive partial objective S 32  of this catadioptric objective as compared to a full refractive system is relieved from the burden of Petzval correction, it can be simplified. The waist and bulge configuration with two and more waists of state-of-the-art refractive microlithographic reduction projection objectives is therefore not needed. Only one waist of minor beam reduction remains. Consequently the refractive partial objective S 32  can be shorter, smaller in diameter and can have less lenses. Transmission and contrast are thus increased, while cost is decreased. Aspheric lens surfaces further help in this effect. 
     As the catoptric partial objective S 31  is free of lenses, its diameter is not critical: Precision aspherical mirrors with diameters of more than one meter are state of the art in astronomy, for example. 
     Obviously the arrangement of catoptric and refractive partial objective also can be changed in sequence. Then the diameter of the catoptric partial system is reduced in consequence of the imaging ratio of the refractive partial objective. 
     For reasons of good accessibility of object Ob and image Im and of more design space for correction, it is advantageous if this system also is extended to a first refractive partial objective S 41 , a catoptric partial objective S 42  and a second refractive partial objective S 43  with intermediate images IMI 1  and IM 12 , as shown in the example of FIG.  4 . 
     The advantages of the first two embodiments with minimal obscuration and of the third example without big lenses between the mirrors M 1 , M 2  can thus be combined. 
     Table 3 gives the design data of this example. This is a 157 nm objective with all crystal lenses, most of LiF and some of NaF, giving excellent chromatic properties for an unnarrowed F 2  laser with 1,5 pm band width. Reduction ratio is 1:5, maximum image field height is 11,88 mm, NA=0,75. Maximum lens diameter is 190,5 mm, maximum mirror diameter is 201 mm. The overall length Ob-Im is 1,459 m. 
     The use of crystal lenses in DUV to VUV microlithographic objectives is made here in adaptation of the earlier application DE 199 29 701.0 dated Jun. 29, 1999 (99032 P) of co-inventor Schuster and the same assignee. This cited application as a whole shall be part of the disclosure of this application, too. 
     Consequently, negative NaF lenses are entered, plus one positive NaF meniscus  408 ,  409  in the first partial objective S 41 , which reduces lateral chromatic aberration, in an overall LiF lens system. 
     Aspheric surfaces are entered into this design at a number of surfaces, where this is advantageous. Consequently, also the mirrors  440  and  441  are aspheric. 
     In the first, reducing partial objective S 41 , the second bulge comprises one asphere, the second waist one asphere, and the third bulge 2 aspheres. In the third partial objective S 43  the first bulge comprises one asphere, while the second of the two bulges comprises 2 aspheres. 
     The aspheric surfaces of the example of tab. 3 are described by          P        (   h   )       =         δ   *     h   2         1   +     √   1     -       (     1   -   EX     )     *     δ   2     *     h   2           +       C   1          h   4       +   ⋯   +       C   n          h       2      n     +   2                                  
     Where P is the height deviation as a function of the radius h (ray height with respect to the optical axis) with the aspheric constants C 1  to C 6  as given in table 3.δis the inverse of the radius given in the table. 
     The objective has a high correction quality, as the wavefront error calculated for two lines of 1 pm spectral distance is less than 8 millilambda at the maximum field height and reduces to less than five millilambda on the optical axis. 
     The central obscuration of the system can be designed to need by enlarging distance and diameter of the mirrors  440 ,  441  of the catoptric partial objective S 42 . 
     Ring sector field imaging is conventional with many catoptric and catadioptric projection exposure systems of generally asymmetric construction. Such can also be realized within the invention. Then, the mirrors only need an off-axis ring sector opening for entering of the light beam, and consequently the pupil only has a two sector obscuration with further reduced effects compared to the circular central obscuration. 
     FIG. 5 schematically shows a microscope with an objective according to the invention. 
     As such primarily makes sense for a DUV/VUV inspection microscope, direct visual observation by an ocular is not shown, but an image detector CCD of any appropriate known sort is provided in the image plane of the objective. The objective is constituted by two refractive partial objectives S 51 , S 53  and the intermediate catoptric or catadioptric partial objective S 52 . The example shows two coaxial opposite mirrors M 1 , M 2  and one negative lens L in it. 
     The design of the objective is generally as shown in the embodiments described above, but with image and object plane exchanged to obtain magnification, and with higher imaging ratio and smaller field. 
     An illumination system III illuminates the object Ob appropriately. 
     
       
         
               
             
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
               
             
               
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
             
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 0, 75 N.A., −2 = 157 nm, β = 6X, 17 × 7 mm double-telecentric 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                   
                 RADIUS 
                 THICKNESS 
                 APERTURE 
               
               
                   
                 Element 
                 [mm] 
                 [mm] 
                 RADIUS [mm] 
               
               
                   
                   
               
               
                   
                 OB 
                 — 
                 41.365 
               
               
                   
                  1 
                 207.804 
                 15.0000 
                 64 
               
               
                   
                  2 
                 7154.0 
                 85.7060 
               
               
                   
                  3 
                 −148.152 
                 10.000 
                 60 
               
               
                   
                  4 
                 −480.523 
                 27.979 
               
               
                   
                  5 
                 275.460 
                 21.000 
                 68 
               
               
                   
                  6 
                 −420.424 
                 18.169 
               
               
                   
                  7 
                 91.68 
                 20.000 
                 62 
               
               
                   
                  8 
                 231.534 
                 102.963 
               
               
                   
                  9 
                 −62.100 
                 5.000 
                 25 
               
               
                   
                 10 
                 551.104 
                 10.065 
               
               
                   
                 11 
                 −77.910 
                 9.000 
                 32 
               
               
                   
                 12 
                 −47.566 
                 1.000 
               
               
                   
                 13 
                 −281.444 
                 12.500 
                 41 
               
               
                   
                 14 
                 −83.966 
                 1.000 
               
               
                   
                 15 
                 −1256.9 
                 17.000 
                 43 
               
               
                   
                 16 
                 −69.116 
                 1.000 
               
               
                   
                 17 
                 99.668 
                 7.000 
                 40 
               
               
                   
                 18 
                 60.790 
                 0.978 
               
               
                   
                 19 
                 63.022 
                 18.000 
                 37 
               
               
                   
                 20 
                 −177.094 
                 1.000 
               
               
                   
                 21 
                 65.632 
                 5.000 
               
               
                   
                 22 
                 43.522 
                 9.388 
               
               
                   
                 23 
                 44.597 
                 7.000 
                 23 
               
               
                   
                 24 
                 115.690 
                 20.474 
               
               
                   
                 IMI1 
                 — 
                 −5.072 
               
               
                   
                 M 2 
                 220.905 
                 16.140 
                 115  
               
               
                   
                 25 
                 349.084 
                 11.500 
                 112  
               
               
                   
                 26 
                 150.213 
                 131.449 
               
               
                   
                 27 
                 −163.770 
                 11.500 
                 105  
               
               
                   
                 28 
                 −381.158 
                 17.158 
               
               
                   
                 M1 
                 −228.356 
                 115 
               
               
                   
                 29 
                 −42.092 
                 21.059 
                 35 
               
               
                   
                 30 
                 −51.728 
                 1.000 
               
               
                   
                 31 
                 −194.937 
                 18.000 
                 59 
               
               
                   
                 32 
                 −113.392 
                 1.000 
               
               
                   
                 33 
                 −1132.0 
                 18.000 
                 70 
               
               
                   
                 34 
                 −193.134 
                 1.000 
               
               
                   
                 35 
                 458.425 
                 18.000 
                 74 
               
               
                   
                 36 
                 −386.456 
                 93.349 
               
               
                   
                 37 
                 171.069 
                 27.160 
                 78 
               
               
                   
                 38 
                 −1302.6 
                 1.000 
               
               
                   
                 39 
                 115.683 
                 12.796 
                 71 
               
               
                   
                 40 
                 79.902 
                 53.335 
               
               
                   
                 41 
                 −108.436 
                 37.180 
                 61 
               
               
                   
                 42 
                 −140.231 
                 1.000 
               
               
                   
                 43 
                 171.662 
                 24.000 
                 71 
               
               
                   
                 44 
                 −1877.0 
                 29.921 
               
               
                   
                 45 
                 −118.760 
                 37.456 
                 66 
               
               
                   
                 46 
                 −131.389 
                 1.000 
               
               
                   
                 47 
                 153.982 
                 21.000 
                 73 
               
               
                   
                 48 
                 1445,6 
                 1.049 
               
               
                   
                 49 
                 72.396 
                 20.001 
                 59 
               
               
                   
                 50 
                 76.113 
                 1.000 
               
               
                   
                 51 
                 53.654 
                 49.996 
                 49 
               
               
                   
                 52 
                 69.967 
                 16.341 
               
               
                   
                 LM 
                 — 
                 — 
               
               
                   
                   
               
             
          
           
               
                 Aspheric Surface Data 
               
               
                   
               
             
          
           
               
                   
                 9: 
                 ASO = 0 
                 AS1 = 0 
                 AS2 = −1.6880e-06 
               
             
          
           
               
                   
                 AS3 = 1.5172e-10 
               
             
          
           
               
                   
                 AS4 = −1.1366e-12/AS5 = 1.3050e-16/AS6 = 1.7402e-18 
               
             
          
           
               
                   
                 AS7 = −2.4094e-21 
               
             
          
           
               
                   
                 M1: 
                 ASO = 0 
                 AS1 = 0 
                 AS2 = −2.1332e-09 
               
             
          
           
               
                   
                 AS3 = −1.157e-13 
               
             
          
           
               
                   
                 AS4 = −2.4958e-18/AS5 = 2.735e-23/AS6 = −7.4436e-27 
               
             
          
           
               
                   
                 AS7 = 1.5059e-31 
               
             
          
           
               
                   
                 M2: 
                 ASO = 0 
                 AS1 = 0 
                 AS2 = 1.7841e-09 
               
             
          
           
               
                   
                 AS3 = 6.8616e-14 
               
             
          
           
               
                   
                 AS4 = 3.6976e-18/AS5 = 5.2619e-23/AS6 = −2.331e-27 
               
             
          
           
               
                   
                 AS7 = 2.8845e-31 
               
               
                   
                 M1, M2 central hole r = 15,3 nm 
               
               
                   
                 Index of refraction CaF 2  at 157 nm: n = 1,55971 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
             
               
               
             
               
               
               
               
             
               
               
             
               
               
               
               
             
               
               
             
               
               
               
               
             
               
               
             
               
               
               
               
             
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 5×, .75 N.A., 22 × 9 mm, λ = .157 μm 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                   
                 RADIUS 
                 THICKNESS 
                 APETURE 
               
               
                   
                 Element 
                 [mm] 
                 [mm] 
                 RADIUS [mm] 
               
               
                   
                   
               
               
                   
                 OB 
                 Telecentric 
                 34.000 
               
               
                   
                 201 
                 170.721 
                 15.000 
                 73 
               
               
                   
                 202 
                 183.404 
                 70.512 
               
               
                   
                 203 
                 −88.583 
                 10.000 
                 72 
               
               
                   
                 204 
                 −109.418 
                 0.097 
               
               
                   
                 205 
                 489.985 
                 31.998 
                 86 
               
               
                   
                 206 
                 −223.861 
                 105.847 
               
               
                   
                 207 
                 211.214 
                 18.000 
                 80 
               
               
                   
                 208 
                 1008.7 
                 132.111 
               
               
                   
                 209 
                 98.261 
                 7.000 
                 38 
               
               
                   
                 210 
                 75.231 
                 9.337 
               
               
                   
                 OD 
                 — 
                 6.429 
                 obscuring 
               
               
                   
                   
                   
                   
                 disk 
               
               
                   
                   
                   
                   
                 r = 6,75 mm 
               
               
                   
                 211 
                 −105.403 
                 28.061 
                 35 
               
               
                   
                 212 
                 −103.952 
                 1.000 
               
               
                   
                 213 
                 2546.4 
                 21.782 
                 56 
               
               
                   
                 214 
                 −129.850 
                 1.000 
               
               
                   
                 215 
                 459.497 
                 25.167 
                 59 
               
               
                   
                 216 
                 −117.119 
                 1.000 
               
               
                   
                 217 
                 76.297 
                 7.000 
                 50 
               
               
                   
                 218 
                 52.636 
                 5.014 
               
               
                   
                 219 
                 60.098 
                 27.883 
                 45 
               
               
                   
                 220 
                 −254.989 
                 1.000 
               
               
                   
                 221 
                 158.480 
                 18.301 
                 38 
               
               
                   
                 222 
                 −1889.6 
                 19.412 
               
               
                   
                 IMI 
                   
                 −4.449 
               
               
                   
                 M2 
                 198.917 
                 11.198 
                 115 
               
               
                   
                 223 
                 249.698 
                 11.500 
                 115 
               
               
                   
                 224 
                 141.621 
                 95.251 
               
               
                   
                 225 
                 −146.113 
                 11.500 
                 105 
               
               
                   
                 226 
                 −279.951 
                 14.507 
               
               
                   
                 M1 
                 −195.876126 
                   
                 115 
               
               
                   
                 IMI2 
                 — 
                 27.988 
               
               
                   
                 227 
                 −29.245 
                 26.188 
                 28 
               
               
                   
                 228 
                 −38.617 
                 1.000 
               
               
                   
                 229 
                 −212.943 
                 16.904 
                 64 
               
               
                   
                 230 
                 −108.498 
                 1.000 
               
               
                   
                 231 
                 −1195.7 
                 19.000 
                 74 
               
               
                   
                 232 
                 −186.309 
                 1.000 
               
               
                   
                 233 
                 397.280 
                 24.000 
                 82 
               
               
                   
                 234 
                 −447.100 
                 40.123 
               
               
                   
                 235 
                 184.325 
                 28.000 
                 82 
               
               
                   
                 236 
                 −5827.0 
                 1.000 
               
               
                   
                 237 
                 94.479 
                 15.000 
                 71 
               
               
                   
                 238 
                 73.235 
                 52.490 
               
               
                   
                 239 
                 −84.776 
                 10.000 
                 58 
               
               
                   
                 240 
                 −134.685 
                 0.997 
               
               
                   
                 241 
                 548.320 
                 30.000 
                 72 
               
               
                   
                 242 
                 −202.022 
                 1.370 
               
               
                   
                 243 
                 244.314 
                 24.000 
                 71 
               
               
                   
                 244 
                 −390.876 
                 9.997 
               
               
                   
                 245 
                 −154.779 
                 26.099 
                 69 
               
               
                   
                 246 
                 −221.429 
                 1.000 
               
               
                   
                 247 
                 170.308 
                 27.000 
                 69 
               
               
                   
                 248 
                 5689.0 
                 1.000 
               
               
                   
                 249 
                 82.493 
                 29.706 
                 58 
               
               
                   
                 250 
                 66.456 
                 1.000 
               
               
                   
                 251 
                 38.604 
                 31.198 
                 38 
               
               
                   
                 252 
                 74.002 
                 16.468 
               
               
                   
                 IM 
                 — 
                 — 
                 11.9 
               
               
                   
                   
               
             
          
           
               
                 Aspheric Surface Data 
               
               
                   
               
             
          
           
               
                   
                 Surface 209 
               
             
          
           
               
                   
                 ASO = 0 
                 AS1 = 0 
                 AS2 = −1.9059e-17 
               
             
          
           
               
                   
                 AS3 = 5.2904e-10/AS4 = −2.9602e-13/AS5 = 2.9727e-16 
               
               
                   
                 AS6 = −3.3981e-19/AS7 = 3.3504e-23 
               
               
                   
                 Surface 217 
               
             
          
           
               
                   
                 ASO = 0 
                 AS1 = 0 
                 AS2 = −2.7436e-07 
               
             
          
           
               
                   
                 AS3 = −1.1707e-12/AS4 = −1.1841e-14/AS5 = 1.8131e-17 
               
               
                   
                 AS6 = −7.5053e-21/AS7 = 1.3749e-24 
               
               
                   
                 Surface M1 
               
             
          
           
               
                   
                 ASO = 0 
                 AS1 = 0 
                 AS2 = 1.9405e-09 
               
             
          
           
               
                   
                 AS3 = 9.5605e-14/AS4 = −2.6910e-17/AS5 = 5.9514e-23 
               
               
                   
                 AS6 = −7.7031e-26/AS7 = 1.8364e-30 
               
               
                   
                 Surface M2 
               
             
          
           
               
                   
                 ASO = 0 
                 AS1 = 0 
                 AS2 = 3.2910e-09 
               
             
          
           
               
                   
                 AS3 = 1.4964e-13/AS4 = −1.2351e-17/AS5 = 2.4844e-21 
               
               
                   
                 AS6 = −1.9615e-25/AS7 = 6.7644e-30 
               
               
                   
                 M1, M2 central hole r = 15,5 mm 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
               
               
               
               
             
               
             
               
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
             
             
               
                   
                 SURFACE 
                 RADI I 
                 THICKNESS 
                 MATERIAL 
               
               
                   
                   
               
               
                   
                 Ob 
                   
                 31.542 
               
               
                   
                 402 
                 161.992 
                 15.188 
                 LiF 
               
               
                   
                 403 
                 469.503 
                 19.672 
               
               
                   
                 404 
                 231.249 
                 8.649 
                 LiF 
               
               
                   
                 405 
                 323.701 
                 81.163 
               
               
                   
                 406 
                 −125.044 
                 7.000 
                 LiF 
               
               
                   
                 407 
                 1233.917 
                 29.038 
               
               
                   
                 408 
                 −136.3150 
                 28.504 
                 NaF 
               
               
                   
                 409 
                 −110.661 
                 42.406 
               
               
                   
                 410 
                 166.198 
                 38.763 
                 LiF 
               
               
                   
                 411 
                 −426.980 
                 33.045 
               
               
                   
                 412 
                 102.987 
                 42.894 
                 LiF 
               
               
                   
                 413 
                 −497.639 
                 3.533 
               
               
                   
                 414 
                 −344.154 
                 7.000 
                 NaF 
               
               
                   
                 415 
                 110.870 
                 62.455 
               
               
                   
                 416 
                 −313.200 
                 7.000 
                 LiF 
               
               
                   
                 417 
                 306.167 
                 12.322 
               
               
                   
                 AS1 
                 ∞ 
                 4.589 
               
               
                   
                 419 
                 −294.9867 
                 7.21 
                 NaF 
               
               
                   
                 420 
                 139.1333 
                 10.42 
               
               
                   
                 421 
                 −198.121 
                 17.91 
                 LiF 
               
               
                   
                 422 
                 −67.419 
                 .7642 
               
               
                   
                 423 
                 −423.496 
                 14.9924 
                 LiF 
               
               
                   
                 424 
                 −117.918 
                 .8112 
               
               
                   
                 425 
                 743.808 
                 8.0149 
                 NaF 
               
               
                   
                 426 
                 123.869 
                 .9171 
               
               
                   
                 427 
                 128.249 
                 44.3083 
                 LiF 
               
               
                   
                 428 
                 −90.153 
                 .8501 
               
               
                   
                 429 
                 230.303 
                 11.2449 
                 LiF 
               
               
                   
                 430 
                 1688.121 
                 1.1630 
               
               
                   
                 431 
                 122.245 
                 7.9843 
                 NaF 
               
               
                   
                 432 
                 59.579 
                 .7500 
               
               
                   
                 433 
                 60.793 
                 24.9206 
                 LiF 
               
               
                   
                 434 
                 −934.252 
                 1.1385 
               
               
                   
                 435 
                 87.724 
                 10.9289 
                 LiF 
               
               
                   
                 436 
                 74.6528 
                 7.4167 
               
               
                   
                 437 
                 43.171 
                 13.3010 
                 LiF 
               
               
                   
                 438 
                 47.425 
                 5.000 
               
               
                   
                 IMI1 
                 ∞ 
                 135.0601 
               
               
                   
                 440 
                 −248.671 
                 −135.,0601 
               
               
                   
                 441 
                 243.629 
                 135.2019 
               
               
                   
                 IMI2 
                 ∞ 
                 21.4887 
               
               
                   
                 443 
                 −39.71329 
                 27.9107 
                 LiF 
               
               
                   
                 444 
                 −53.040 
                 2.7851 
               
               
                   
                 445 
                 −218.179 
                 26.3722 
                 LiF 
               
               
                   
                 446 
                 −100.461 
                 2.5410 
               
               
                   
                 447 
                 −444.958 
                 33.4544 
                 LiF 
               
               
                   
                 448 
                 −125.627 
                 3.4864 
               
               
                   
                 449 
                 205.875 
                 52.0553 
                 LiF 
               
               
                   
                 450 
                 −445.534 
                 3.1476 
               
               
                   
                 451 
                 −393.14835 
                 7.1061 
                 NaF 
               
               
                   
                 452 
                 529.85954 
                 10.9028 
               
               
                   
                 453 
                 171.69804 
                 54.8263 
                 LiF 
               
               
                   
                 454 
                 −3285.94521 
                 2.9859 
               
               
                   
                 455 
                 1249.94523 
                 10.7714 
                 NaF 
               
               
                   
                 456 
                 188.56505 
                 53.9985 
               
               
                   
                 457 
                 −102.09026 
                 18.5249 
                 LiF 
               
               
                   
                 458 
                 −114.02167 
                 3.1811 
               
               
                   
                 459 
                 −108.06602 
                 36.3405 
                 LiF 
               
               
                   
                 460 
                 −122.25579 
                 .8148 
               
               
                   
                 461 
                 237.93896 
                 30.4791 
               
               
                   
                 462 
                 −591.44374 
                 33.927 
               
               
                   
                 463 
                 −131.73596 
                 9.2936 
                 NaF 
               
               
                   
                 464 
                 −816.022 
                 4.0340 
               
               
                   
                 465 
                 −921.759 
                 43.70 
                 LiF 
               
               
                   
                 466 
                 −161.952 
                 12.96 
               
               
                   
                 467 
                 135.682 
                 35.56 
                 LiF 
               
               
                   
                 468 
                 485.873 
                 7.77 
               
               
                   
                 469 
                 74.486 
                 26.357 
                 LiF 
               
               
                   
                 470 
                 88.618 
                 3.623 
               
               
                   
                 471 
                 64.861 
                 56.517 
                 LiF 
               
               
                   
                 472 
                 65.449 
                 20.524 
               
               
                   
                 Im 
                 ∞ 
               
               
                   
                   
               
             
          
           
               
                 Aspheric constants 
               
               
                   
               
             
          
           
               
                 11 A 
                 C1  .43635053E-07 
                 C2 −.10565814E-11 
                 C3  .33243511E-16 
               
               
                   
                 C4 −.27930883E-20 
                 C5  .11432015E-24 
                 C6 −.33257819E-29 
               
               
                 19 A 
                 C1 −.96601935E-06 
                 C2  .70267826E-10 
                 C3  .31115875E-13 
               
               
                   
                 C4 −.43329420E-17 
                 C5 −.41852201E-20 
                 C6  .30053413E-25 
               
               
                 25 A 
                 C1 −.29611487E-07 
                 C2  .20760499E-10 
                 C3 −.12518124E-14 
               
               
                   
                 C4 −.52770520E-18 
                 C5  .86996061E-22 
                 C6 −.19792693E-27 
               
               
                 34 A 
                 C1 −.15885997E-06 
                 C2  .52924012E-10 
                 C3 −.73552870E-14 
               
               
                   
                 C4 −.86379790E-18 
                 C5  .59324551E-21 
                 C6 −.39153227E-25 
               
               
                 40 A 
                 C1  .23060301E-07 
                 C2  .81122530E-13 
                 C3 −.32179819E-17 
               
               
                   
                 C4  .71766836E-21 
                 C5 −.46055104E-26 
                 C6  .12956188E-31 
               
               
                 41 A 
                 C1 −.11072232E-07 
                 C2  .31369498E-13 
                 C3  .77375306E-17 
               
               
                   
                 C4  .19892497E-21 
                 C5 −.89740115E-26 
                 C6  .68627541E-31 
               
               
                 49 A 
                 C1  .56699275E-08 
                 C2  .57127904E-12 
                 C3  .59227712E-16 
               
               
                   
                 C4  .21077816E-20 
                 C5  .15595431E-24 
                 C6 −.13690607E-29 
               
               
                 63 A 
                 C1 −.17174244E-07 
                 C2  .18573484E-11 
                 C3 −.42802250E-16 
               
               
                   
                 C4  .51394491E-20 
                 C5 −.37650847E-24 
                 C6  .22638360E-28 
               
               
                 68 A 
                 C1  .10650246E-07 
                 C2  .20265609E-11 
                 C3 −.88014450E-16 
               
               
                   
                 C4  .91073382E-20 
                 C5 −.55181052E-24 
                 C6  .37391374E-28