DD222426A1 - OPTICAL SYSTEM - Google Patents

Abstract

The invention relates to an optical system and can be used in optically imaging high-performance systems in the wavelength range 150 to 10 000 nm. The object of the invention to remedy the disadvantages of the prior art, the object is to provide an optical system in which the same or reduced lens number compared to optical glass, the secondary spectrum is corrected over a wide spectral range depending on the application. This task is solved by an optical system in which BaF ind 2 is used as a monocrystalline optical medium and thus the choice of partner glasses can be made more favorable. figure

Description

Field of application of the invention

The invention can be used in imaging high-performance systems in the wavelength range 150 to <10000 nm.

Characteristic of the known technical solutions

Known technical solutions for optical imaging high performance systems based on the use of optical glass and individual, selected single crystals such. The use of optical glass has its limitation in limiting the transmission to the wavelength range of about 380 to 1500 nm and the small deviations of the relative partial dispersion of the normal straight line, whereby the correction of the secondary spectrum is limited.

The commonly used single crystals have transmissions that allow the modeling of optical systems even in more extreme spectral ranges (UV, IR). The deviation from the normal line of the relative Teiidispersion is generally higher than optical glasses. The difficulty is to find partner glasses that sufficiently allow the correction of the secondary spectrum and other aberrations.

As a result, a large number of lenses are needed in optical systems. There are also problems in the

Processing technology of the crystals. · '

Object of the invention

The aim of the invention is an optical system which eliminates the disadvantages of the known prior art.

Explanation of the essence of the invention

The invention has for its object to provide an optical system in which corrected at the same or reduced number of lenses compared to optical glass, the secondary spectrum depending on the application over a large spectral range

This object is achieved by an optical system according to the invention characterized in that barium fluoride as monocrystalline optical medium

BaF ₂ is used. .-. · '·

In combination with other optical glasses, the secondary spectrum can be additionally corrected by the use of BaF ₂ up to the deep UV with an equivalent or reduced lens number compared to optical glass. In this case, it is easier to find favorable partner glasses with respect to the optical characteristics and to apply a processing technique comparable to the fluorspar. The correction of the secondary spectrum according to the invention extends over a wavelength range of 150 to 2000 nm, depending on the intended use. The characteristic values of an inventive

Solution are long in table. '

embodiment

The essence of the invention will be explained in more detail with reference to a fine-measuring objective 0.3 / 20 shown in the drawing, the schematic structure of which is shown in FIG.

Along the optical axis 0-0 'lenses L 1 ... L 10 are arranged in four groups of putties and as a single biconcave lens. The individual lenses are characterized by their center thicknesses d " their radii η and the refractive indices n, while the required air spacings are denoted by Ij. By using BaF ₂ as the optical medium for lens L 4 and L 6, a planapochromate can be calculated for the wavelength range from 480 to 800nm, with the secondary spectrum nearly zero over the entire range. ·,

A hitherto known solution was a Planaphromat equal number of lenses and magnification, which was corrected in the wavelength range of 480 to 643.87 nm, the secondary spectrum was 2.8λ / A ² .

- 3 - 26U 454 JL

Table 1 . ,

S = -13.691

S '= 144.62 with 39nmBK7 and 56mm BaK4 GIase path

Ep = - -43.5 radius ' + 56.2 Γι = -16.4 r ₂ = +55.7 ^r 3 ⁼ +23.9 U = -33.5 Γ5 = +48.0 r ₆ = +21.0 ^r 7 = -21.0 ^r 8 ⁼ -104.6 r ₉ = + 15.1  =ο = -51.7 Γη = + 20.4 r ₁₂ = -30.8 Γ13 = +28.8 Γ14 = Γ15 =

Refractive index n _e  = '1 distance 2.0 "i = 1.531870 6.0 n ₂ = 1.55440 di = 0.1 n ₃ = 1 d ₂ = 2.0 n ₄ = 1.694160 I1 = 6.0 n ₅ = 1.47586 d ₃ = 38.4 n ₆ = 1 d ₄ . = 3.5 n ₇ =. 1.531870 \ = 10.0 n ₈ = 1.47586 d ₅ = 3.5 n ₉ = 1.531870 d ₆ = 93.6 ⁿ 10 = 1 d ₇ = 3.73 Πΐ1 = 1.727940 I3 = 1.4 n ₁₂ = 1.531870 d ₈ = 2.0 n " =, 1 d _g = 1.86 n ₁₄ = 1.734438 I4 = Π15 = 1. d ₁₀ = Π16

Claims (3)

-2- 260 454 Invention claims: 1. Optical system in which optical glasses and single crystals are used as optical media, characterized in that BaF _{2 is} used as a single-crystal medium, that in conjunction with other optical media, the secondary spectrum can be corrected to the deep UV. ' 2. Optical system according to item 1, characterized in that the correction of the secondary spectrum, depending on the application over a wavelength range of 150 to 2000 nm extends. 3. Optical system according to item 1 and 2, characterized in that a structural design is characterized according to the values given in Table 1. For this 1 page drawings.