DE2010932A1 - Optical system for the transmission of signals - Google Patents

Description

Dipl.-Ing. Egon Prince Dr. Gertrud Hauser Dipl.-Ing. Gottfried Leiser

Patent attorneys

Telegrams: Labyrinth Munich

Telephone: 83 15 10 'Postal checking account: Manchen 117078

8000 Munich 60, _ "" _ .._.

Ernsbergerstrasse ir '"RLlSfB

Our reference: T 834

TRANSPORMATEURS DE MESURE WALTER

64, avenue Lenine
94-Gentllly (YaX de Marne) / France.

Optical system for the transmission of signals

The invention relates to optical systems for transmission of measurement or control signals, in particular for measuring the current flowing in a high-voltage line by means of a polarized light beam, whose plane of polarization is changed by a magnetic field generated by the current to be measured.

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It

It has already been proposed to use the magneto-optical effect known as the Faraday effect for this purpose, whereby a polarized light bundle is emitted from a monochromatic light source at about earth potential and successively through two transparent elements with a high Verdet constant, such as heavy flint glasses , one of which is arranged in a magnetic field generated by the high-voltage current to be measured and the other in a magnetic field which is intended to compensate for the rotation of the plane of polarization of the light beam generated by the first field. The strength of the current flowing through the high-voltage line is then obtained from the strength of the current generating the compensation field by comparing the number of ampere turns.

The upper flint glass, which is arranged in a winding with some of the current to be measured enen windings , is generally arranged for reasons of insulation near the high-voltage line and is therefore at a distance of a few meters from the lower flint glass, which is in a further, the KompensatIonsfeld generating winding is arranged.

In order to increase the sensitivity of the measuring arrangement , it has also been proposed to let the light beam run back into itself with the aid of a reflector element so that each flint glass is penetrated twice, namely by the incident and the reflected beam.

Of the

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The gain in speed achieved by this arrangement, however, remains fairly theoretical, if not take certain precautions with the optical used Annex. Are to be observed.

Since the light source is generally small in size owns and the sent one. Lies current in proportion is low, it is important that after an optical Distance of the order of 10 m the receiver receives the maximum amount of transmitted light. With others Words, the immobility of the final image of the light source, its dimensions in the order of magnitude of mm, in the sensitive plane of the photodetector of the receiver must, despite the movements, the Vibrations of the optical arrangement or the lateral displacement of certain parts of the same received stay.

The aim of the invention is to achieve a catadioptric effect, essentially on the basis of improvements in the optical system, which leads to ensuring this immobility of the final image in such a way that any risk of obscuring the useful flow is avoided and the simultaneous achievement of great precision and great accuracy Sensitivity of measurements with polarized light despite the large optical paths to be covered by the light bundle, in particular through the flint glasses.

The invention creates an optical system in which one of a preferably monochromatic, one

first 009839/1924

Light bundle emitted by the light source assigned to the first objective lens via a semitransparent mirror a first and second transparent element is thrown and reflected off a reflector so that it runs back in itself to a photoelectric receiver, characterized in that to achieve a catadioptric effect

a) the light source is arranged with respect to the first objective in such a way that its image after reflection on the semitransparent mirror and passage through the first

P transparent element in the main plane of entry of a second, between the two transparent elements arranged lens arises,

b) the second transparent element is arranged on the optical axis in such a way that that of the second objective generated image of the entrance pupil after passing through the second transparent element on the entrance surface this latter arises,

c) the entrance surface of the second transparent element has such a curvature that the image of the Main exit plane of the second lens on the rear

ψ external, reflective surface is created,

d) the rear surface of the second transparent element is metallized to form a reflector and has such a curvature that:

- On the one hand, the image of this rear surface with respect to the entry surface of this element in the The main exit plane of the second objective is created and

009839/1924 - on the other hand

- on the other hand, the image that it takes from the image of the entrance pupil generated on its entrance surface, coincides with this latter image,

e) and the sensitive area of the photoelectric Receiver is arranged in the image plane of the light source, which is through a between the receiver and the receiving lens arranged in a semitransparent mirror is fixed.

The invention is explained in more detail, for example, with the aid of the figures. It shows

Figure 1 schematically shows an optical system according to the invention and

Figure 2 shows a practical embodiment.

With S 1 denotes a light source which, for example consists of a filament lamp and is assigned to a first objective O1 with a large aperture angle. That Light beam falls on a semitransparent mirror M, which is arranged at about ^ 5 ° and the same along an axis A successively through a first transparent element Fl, which in the embodiment made of heavy flint glass with a high Verdet constant consists, a second lens 02 and a second transparent element F2 with a corresponding composition as the first element throws Fl.

The rear surface QM of the element F2 is represented by Me

customization 009839/1924

Made reflective in such a way that the light beam is reflected in itself along the axis A. becomes and after repeated passage through the elements F2, 02, Fl and M a part of the light stream a photodetector PD falls after it has penetrated an additional recording object! ν 05. The flint glass Fl has plane-parallel surfaces, while the surfaces of the flint glass F2 are explained below Way fixed curvature.

The light source S is arranged axially with respect to the objective 01 in such a way that its image Sl after reflection is generated at the mirror M and passage through the flint glass Fl in the main entrance plane of the lens 02.

The axial arrangement of the flint glass F2 is determined in such a way that the image P1 of the entrance pupil P generated by the objective 02 after reflection on the mirror M and passage is located through the flint glass Fl on the entry surface 03 of the flint glass F2.

This surface 03 is given such a curvature that the image S2 of the main exit plane of the objective 02 is created on the other, reflective surface 04. This latter surface 04 also has such a curvature granted that:

- On the one hand, the image S3 of this surface 04 is created in relation to the entrance surface 03 in the main exit plane of the objective 02 and

- on the other hand, the image P2 that it defines from above

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th image Pl generated, coincides with this image Pl on the _v surface 03.

Under these conditions, the light bundle is reflected on the surface Ok and after passing through the flint glass F2, the objective 02, the flint glass F1 and the mirror M, a pupil image P3 is generated in the immediate vicinity of the entrance pupil of the objective 05.

It is also provided the sensitive surface of the photodetector PD in the image plane S4 of the light source S generated by the taking lens 05.

As a result of these arrangements, most of the from the light source S emanating light on the photodetector PD after traveling an optical path on the order of 10 meters there and back. Even when certain optical elements are subjected to a lateral displacement, which for example on a bending of the frame in its middle part or is based on vibrations, can be obtained with the help of flint glass F2 a catadioptric effect showing immobility of the image S4 of the light source in the plane of the photodetector guaranteed.

The arrangement of the optical elements is practical the first flint glass placed inside a rigid frame whose deformations under the action of Impacts or a temperature increase are as small as possible and which, for example, from a Pyrex pipe exists, which may contain an inert gas, which

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has no noticeable absorption at the wavelength used.

Figure 2 shows schematically such an embodiment. The pipe consists of pipe sections T1 to T7, which touch at their ends on carefully polished surfaces and by means of flange tightened by screws V. B are fixed to each other, as shown in the enlarged views in the circles. That Flint glass Fl is fixed inside the tube Tl, the lower part of which ends in a spherical bulge, which cooperates with the part of the tube T2, which has a similar shape, in such a way that a swivel joint Rl arises. Between the ends of the tubes T3, T4 is the Carrier of the lens 02 used, the position of which is regular in the plane of separation. The pipes T5 and T6, from which the latter contains the flint glass F2, also end in spherical bulges, which are another Form swivel joint R2.

This arrangement rests on a carrier St, which has a circular opening, and is supported on this

. by means of the flanges B holding the pipes T2, T3 together ™ set. Under this carrier, the other parts S, 01, M, 05, PD are inside optical elements, not shown Lines arranged.

The swivel joints Rl, R2 each allow the rotary setting the flint glasses Fl, F2. The connection levels between T2, T3 and T4, T5 also enable the Displacement adjustment. If these settings as well

ι the one

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those of the lens 02 are carried out, so that the maximum luminous flux on the photodetector. obtain is, all Plansche B are finally attracted, so that a rigid arrangement is formed, which in the Inside an insulating porcelain case.

For the above-mentioned application with polarized light Of course, a polarizer and analyzer each close to the monochromatic light source and the photodetector provided, the places of which can otherwise be exchanged. In addition, to avoid annoying reflections, the surfaces of the flint glasses and the lenses are treated to reduce reflections for the light used.

The invention is mainly related to high voltage electrical transmission lines for measurement and monitoring of the current flowing through the same as well as for the control of interruption and display devices in the case of the Evidence of abnormally high currents, what the presence indicate a fault on these lines, applicable.

Patent Appeals 0 0 9-839 / 192 4 ^{; :}

Claims (3)

- ίο - claims 1. Optical system for the transmission of measurement or control signals, in particular using polarized light, in which one of a preferably monochromatic, Light bundle emitted via a half-P light source assigned to a light source transmissive mirror thrown through a first and second transparent element and attached to a reflector is reflected so that it runs back in itself to a photoelectric receiver, characterized in that that to achieve a catadioptric effect a) the light source is arranged with respect to the first objective in such a way that its image after reflection on the semitransparent mirror and passage through the first transparent element in the main entrance plane of one second, between the two transparent elements ^ arranged lens arises, b) the second transparent element is arranged on the optical axis in such a way that that of the second objective generated image of the entrance pupil after passing through the second transparent element on the entrance surface this latter arises, c) the entrance surface of the second transparent element has such a curvature that the image of the t rode sh main level 00983 ^ / 192A - li - step main plane of the second lens arises on the rear ^ reflecting surface, d) the rear surface of the second transparent element is metallized to form a reflector and has such a curvature that: - on the one hand, the image of this rear surface in relation to the entrance surface of this element arises in the main exit plane of the second objective and - on the other hand, the image that it generates of the image of the entrance pupil on its entrance surface, with this the latter picture coincides, e) and the sensitive area of the photoelectric Receiver is arranged in the image plane of the light source, which is passed through a between the receiver and the semi-transparent Mirror arranged receiving lens set is. 2. Optical system according to claim 1, characterized in that the light is a polarized light and that the transparent elements body with high Verdet constant, like heavy flint glasses, in which the plane of polarization of the light is caused by the magneto-optical effect can be changed. 3. Optical system according to claim 1 or 2, characterized in that that the parts of the plant partially inside a rigid arrangement of filled with inert gas Pyrex pipe sections are attached. 009839/1924