DE1807247A1 - Light guide arrangement for measuring rotational speeds - Google Patents

Description

IUI (III Il

ENWICKLUNOSRIHG SUB GMBH Münohen, November 5th, 1968

m ₃ o 008 """" 1807247

Kre / Sohö

Guide arrangement for measuring rotational speeds.

The invention relates to a light guide arrangement for measuring Rotational speeds using the Sagnao effect, with the Sensitivity of a Sagnac interferometer is used to measure one with and one against the rotation circulating light beam.

Arrangements have already been proposed in which the sensitivity of a Sagnac interferometer is increased by measuring the in- ' interference of a multiple circulating light beam by means of a Luoite tube, the light beam in each case in a transparent glass pulse or according to a further arrangement by means of a coherent light source in a coil made of glass fibers with and in a coil the rotation of the measuring body is brought to multiple revolutions. The advantages of these arrangements are undeniable. For the requirements of the most precise measurements, however, it was found that primarily thermal differences in the individual coils cause measurement errors. ™

The object of the invention is to create an arrangement the errors that occur due to thermal, acoustic or chemical differences in the individual glass fibers can be eliminated and thereby Measurement errors can be avoided *

The invention solves the problem by arranging a coherent light source in a single fiberglass spool and placing a beam splitter between the light source and the spool in such a way that the end of the

009822/1127 ' ² "

ENTVICKLUNGSRING SÜD GMBH - 2 - November 5, 1968

MUNICH

EM 30 008
Kre / Schö

Coil a beam 'is incident.

Through these measures, differences, especially in the Heating of the individual glass fibers as they were previously due to the arrangement of two coils have occurred, because the beam moving with the rotation and the one against the rotation meet within a single coil always has the same different ratios, that is, they both have the same conditions and are both afflicted with the same changes (phase shift) when they emerge again from the ends of the coil. This increases the measurement accuracy the arrangement increased significantly.

In a further development of the arrangement it is proposed that the end face the ends of the fiberglass spool are ground at a certain angle to the fiber axis. This measure prevents the The light reflected from the glass fiber end face enters the interferometer and thereby significantly falsifies the measurement result. at With a suitable bevel angle of the glass fiber ends, it is even possible to achieve almost complete absence of reflection.

The invention is described below in an exemplary embodiment and drawn. Show it

FIG. 1 is a schematic diagram of the arrangement according to the invention FIG. 2 shows the detail A according to FIG. 1 on an enlarged scale.

009822/1127 " ³ "

BATH ORIGINAL

ENTWICKLÜNGSRING SÜD GMBH - 3 - November 5, 1968

MUNICH

EM 50 008
Kre / Schö

On a platform 10, which moves with the angular velocity ^? rotates in arrow direction, a coherent light source 20 - for example a laser arrangement - is mounted. In front of this is a beam splitter 21 to which the two ends 31 »32 of a fiber optic coil 30 are brought in at a corresponding angle, so that one part of the light beam 22 falls through the beam splitter 21 directly into the end 31 and the other part of the light beam 22 % is deflected and falls into the other end of the coil 32 to the counter-rotating Mehrfaohumlavf. In order to deflect from the interferometer the reflections that arise when the light beam 22 hits the end faces of the glass fiber ends 31 * 32, the ends 31 »32 are ground at a certain angle to the fiber axis. With the appropriate precision, it is possible to choose the bevel angle so that the end faces are practically non-reflective. In general, the reflections are much more intense than the light circulating through the entire coil. The latter, however, can run against one another in the same plane or line without impairment - with regard to intensity, speed, etc. - so that a single fiber optic coil is sufficient for the counter and the rotation of a directional beam. In this way, however, it is possible to eliminate almost all sources of error, since each of the beams running in opposite directions experiences the same changes, which can be attributed, for example, to thermal, chemical, acoustic or also mechanical influences. The measure according to the invention increases the measurement accuracy of the system quite considerably and the sources of error that were still present before are almost completely eliminated.

^009822/1127 UDOHQlNM.

Claims (2)

ENTVICKLTOGSRIIG SÜD GMBH Munich, November 5, 1968 MttNCHEÜ EM 50 008 #, Kre / SeW T patent claims 1. Light guide arrangement for measuring rotational speeds using the Sagnac effect, whereby the sensitivity of a Sagnac interferometer is used to measure a rait and a light beam circulating against the rotation, thereby g · k β η η ζ e worthwhile that at the output a coherent light source (20) a single fiber coil (50), and "wipe light source (20) and coil (50), a beam splitter (21) eo set i" t _t that in each end (51, 52) of the coil (50 ) a part of the beam (22) is incident, which in each case passes into the interferometer (40) after exiting the coil (50). 2. light guide arrangement according to claim 1, characterized in that the end face of the ends (51, 32) of the fiber optic 1 · (50) is ground at a baatiomtem angle to the Faaerachee. Publications drawn in consideration! U.S. Patent 5,102,955 009822/1127 BATH ORIGINAL