US2507990A - Method for amplifying small movements and apparatus for the application thereof - Google Patents

Description

May 16, 1950 2,507,990

G. MINOT METHOD FOR AMPLIFYING SMALL MOVEMENTS AND APPARATUS FOR THE APPLICATION THEREOF Filed June 28, 1946 Patented May 16, 1950 Mer no! FORAMPLIFYING sM LL MOVE- MENTS AND APPARATUS FOR THE APPLI- "CATIONTHEREOF Georges Minot, Ezanville, France A'pplicationJune -28, 194'6QSeria'lNo. 679,963 In France January 1'7, 1945 Section 1, PublicLaw 690, August-'8, 1946 tPatent e'xpires January L7, 1965 4 Claims.

'My invention has 'ior'its object to .provide a method E'fOI' amplifying small .zmovements by means of a photo-cell recordingthe variations in luminosity of a radiologic screen .on which is shown the shadow of the body executing the small movements and exposed to X rays.

Another object of my invention is to provide an apparatus for amplifying small movements of a body irradiated by X rays, said apparatus comprising anX-Iay source, the X-ra-y beam of which impinging upon a radiologic screen on which appears the shadow vof the :body placed between the X-ray source and said screen at the back of which is a photo-cell connected to .an amplifier controlling a measuring instrument.

The rays which light the photo-cell :are advantageously pulsatoryso that it is possible to use an amplifier for alternating current, said amplifier being pref erably tuned to" the frequency of the .pulsatory-rays impinging upon theaphotocell.

It shoul'd'be noticed lastlythat the arrangement forming the object of the invention is :not necessarily limitecl'to the recordingof very small movementsyit may also serve for movements of a certain amplitude.

Other features and advantages-of my invention will appearmoreover in the reading-of the following description with reference to accompanying drawings givenout solely by way of example and wherein:

Fig.1 is a diagrammatic-showing of an arrangement accordingto-myinvention.

Fig. 2 is a part of -a form of execution correspending to Fig. -1-or application thereof to the study of the movements of the veins.

Fig. 3 shows diagrammatically-a modification ofthe system with a stationaryscreen.

Fig. 4 illustratesina diagrammatical perspective view the chief elements of another form'of execution.

Lastly Fig. 5 is a partial view of an arrangement for the occultation of thebeam.

In these different figures, the same "reference numbers designate similar parts.

In the form of execution illustrated in Fig. 1, the apparatus comprises a source of light I, preferably linear, constituted by a filament perpendicular to the plane of the figure. A condenser 2 produces a light beam 3 defined by the diaphragm 4 and falling on a cyclindrical lens 5 the axis of which is perpendicular to the plans of the figure.

This lens 5 forms a luminous beam including a thin flat zone perpendicular to the plane of the figure. In front of said zone lies a screen -3 the .outer edgecof which :9 is trued inza plane perpendicular to the plane of .the :figure eso-that the'screen .8 .may'cut offa more or ;less considerable part of the beaminathe above mentioned thin zone. The remainder -.of the beam impinges onthegphoto-cell -l 0.

This .cell T ll cooperates with .a adirect acur-rent voltage amplifier :which is illustrated as ;con.- stituted by .an electronic :multiplier iii. The cathode of the :photo-icell 'is vgrounded "and sits :anode connected to the :positive pole .of .a high ,tention source through a resistance I 3, 'the atwo ends of which are connected respectively with the grid l4 and thecathode J5 .of'the amplifier tube 1:2. The screening gridl'fi and the secondary cathode ll of this amplifieritube 112 are. also cone 'nected with the positive moles .of high .-voltage :sources While'the'anode 48 is connected :through :a lead :19, also connected through .a resistance Zll to a source of high voltage, and through :a

condenser "21 to :an electrostatic .oscillograph 22 for "recording or for visualsupervision-such as :a quartz oscillograph. The mounting ..would be slightly modified win the :case of a magnetic oscillograph.

.6116 of :the two. elements, cylindrical/dens i5 icr SCH-38111.8, is .stationary awhile thezother .element is connected'withitheibody of whichitaisadesired to study themovements: and which may :be :constituted'aby the I moving in ember-.ofianelectrometer, electroscope or f theilike so that said element may assume a translational or airotationalimovement perpendicularly to thebeam '3 under the icontrol of said movements. This produces ".thus :a .more or lessconsiderable occultation 20f lthe beam 3 by the screen 8, which leads to "corresponding variations in "the current ifiowing "through the :photoecell l0, which variations are transformed and :recorded by the oscill'ograph 22. "The latter may as well make said variations appear under the form of curves on a fiuorescent or the -like screen.

A :milliammeter 24 is inserted in the birciiit -of the amplifier 12 and allows an adj ustment' of 'the system as obtained by adjusting the relative positions of the screen 8 and of the beam 3, whereby the mean intensity given out may be that which corresponds to the proper operation of said amplifier.

Fig. 2 illustrates a form of execution adapted more particularly for use for physiological purposes, for instance for the examination through contact of the movements of the veins, said form of execution including a casing 25 enclosing the source I and the cell 10. One wall 26 of this casing 'gis elastic and carries the screen 8 of which an extension 28 beyond the casing may be set in contact with the vein or the like part of which it is desired to study the movements. Such an apparatus exerts obviously only a very small Pressure on the vein the movements of which are transmitted with a high accuracy.

Fig. 3 shows a further form of execution according to which the source I cooperates with a mirror 29 reflecting into the direction of a photo-cell It! a beam 3 more or less cut off by the screen 8. Said screen 8 is stationary and the mirror 29 is pivotally secured to a pivot 31 round which it rotates under the control of the movement to be examined and which is transmitted to it for instance through a rod 30.

Obviously as in the above example the occultation of the beam and consequently the current flowing through the cell l0 depend on said movement.

In Fig. 4, I designates the source emitting radiations constituted in the present case by a source of X rays fed with direct current cut off at a frequency F and emitting a beam 3; the frequency F is preferably all the higher when the movement is more rapid. Behind an ordinary radiologic screen 32 is arranged a photo-cell I0, the entrance gate into which 33 has an elongated rectangular cross-section and is arranged in a manner such that the small side of said crosssection may be substantially perpendicular to the direction of the movements under examination. This photo-cell I9 is inserted in a system comprising an amplifier 49 and a recorder 4| of a known type. The amplifier is executed for operation at a mean frequency F.

It has been supposed that the above arrangement is used for the examination of the beats of a human heart 34. The beam 3 projects on the radiologic screen 32 a shadow 35 the edge I:

of which passes through the rectangular surface 36 of the screen lying in front of the gate 33 of the photo-cell. This surface 36 is thus more or less invaded by the shadow 35 and the consequent variation in luminosity has an action on the photo-cell [0. The variable electric current generated by the cell is then amplified and used as precedingly for amplifying any desired indicating or recording apparatuses.

The modification of a part of the arrangement illustrated in Fig. 5 differs from the preceding arrangement only through the use of a continuous emitting supply of radiations la in front of which are located occulting means constituted by a disc 31 of a material opaque with reference to the radiation used, lead for instance for X rays and provided with gates or slots 38 or with any other means for modifying its opacity at different points of the disc. Said disc is caused to rotate for instance through the agency of a small motor :39 at a speed such that F slits 38 may pass in front of the source la during unit time. The beam used assumes thus a pulsatory character at a frequency F as in the preceding case.

Obviously, my invention is by no means limited to the details of execution illustrated or described which have been given out solely by way of example. It is also possible to insert an optic system between the radiologic screen and the photo-cell in order to concentrate on the radiation sensitive part of the latter the light from the screen surface which is to be examined.

What I claim is:

1. An arrangement for amplifying small movements, comprising a photo-cell, an amplifier connected with the output of said cell, means controlled by the amplifier for allowing examination of the movements considered, a radiologic screen arranged before said cell, an X-ray source for directing an X-ray beam on said radiologic screen, means for making pulsatory the rays coming from said screen and impinging upon the photocell, means for positioning, in the X-ray beam, a body executing the small movements to be studied the shadow of which appears on said radiologic screen and a diaphragm disposed between the X-ray source and the photo-cell for defining a screen zone wherein is at least one portion of the shadow outline of the body executing the small movements.

2. An arrangement for amplifying small movements as claimed in claim 1, wherein said diaphragm is substantially rectangular and positioned between the radiologic screen and the photo-cell.

3. An arrangement for amplifying small movements as claimed in claim 1, wherein the means for making pulsatory the rays which impinge upon the photo-cell are constituted by periodic occulting means inserted between the X-ray source and the photo-cell.

4. An arrangement for amplifying small movements as claimed in claim 1, wherein the means for making pulsatory the rays which impinge upon the photo-cell are constituted by a rotating opaque disc disposed on the path of the X-ray beam and having peripheric disposed zones which are permeable to the X rays.

GEORGES MINOT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,643,713 Herbig Sept. 27, 1927 1,787,536 Hayes Jan. 6, 1931 1,948,740 Young Feb. 27, 1934 1,976,298 Richter Oct. 9, 1934 1,991,477 Urie Feb. 19, 1935 2,007,220 Smith July 9, 1935 2,183,459 Lehr et a1. Dec. 12, 1939 2,304,191 Mott-Smith Dec. 8, 1942 FOREIGN PATENTS Number Country Date 555,432 Great Britain Aug. 23, 1943

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