US2226990A - Deflecting device - Google Patents

Description

Dec. 31, 1940. i K. scHLEsmsER 2,226,990

DEFLEGTING DEVICE Fil ed July 17, 1934 2 Sheets-Sheet 1 Un venZ'oc:

Dec. 31', 1940. K. SCHLESINGER 2,226,990

DEFLECTING DEVI CE 2 Sheets-Sheet: 2

Filed July '17. 19:54

Mum

Patented Dec. 31, 1940 DEFLECTING DEVICE Application July 17, 1934, Serial No. 735,603 In Germany July 21, 1933 2Claims. The object of the invention is a portable television apparatus with Braun tube, which requires a very low battery'supply, is of low weight, and

requires little spaceandwhich, therefore, is par- 5 ticularly well suited for military-and police pur- The arrangement according to the'invention comprises: 7

1. A Brauntube with preferably small image s'creenfand short bulb, which preferably may be completely enclosed,

2. A small wireless receiver (preferably of the audion type) of the kind known per se,

' 3. An apparatus driven by a small motor for producing exactly saw-tooth deflecting potentials for deflecting thecathode ray in two directions vertical to each other, and v a 4. A buzzer transformerwhich, in conjunction with a small low-volt battery, supplies all of the voltages necessary for operation of the arrangement. I i I According to the invention, the image deflecting voltage generator is so constructed that it is possible to begin the scanning of different sequent pictures with different lines ,(in correspondence with the transmitter) and to adjust as desired the sequence of the lines to be scanned, sothat secret communications may be received Without any diflicultyl i A form of embodimentof the arrangement according to the invention is illustrated by way of example in the drawings, in which Fig. 1 shows diagrammatically the disposal of all parts, whilst in Fig. Zthere is illustrated thedefiecting voltage generator employed according" to the invention as a Whole,

Fig. 3 shows the generator producing the image-deflecting voltage, whilst in Figs. 4-6 there is shown the generator producing the line deflecting voltage. In the drawings:

,l is the Braun, tube with the fluorescent screen 2, the cathode3, the'control element 4 controlling the intensity of the ray, the electron-optical system 5 comprising the negatively biased cylinder and a plate-shaped anode and the pairs of deflecting platesjB and Ii-8 is the deflecting voltage generator" pr'o'clucingthe line and'image deflecting voltages, 9 a wireless receiver, and II) the buzjzer transformer, which supplies the high potentials necessary for operation of the apparatus (for example, 1000 volts anode potential and all requisite-biases).. 1 his the low-volt battery, which'satisfies the complete energy requirement of the apparatus." The transformer arrangement T .t TATEs PATENT j OFFICE may for example consist of a low voltage source,

an interrupter, a transformer and a preferably thermionic rectifier, the primary of the trans former being connected over said interrupter (which may preferably be of the known magnetic type) to said low voltagesource, the secondary of said transformer being connected to the rectifier circuit. In the rectifier circuit there may. be provided a resistance, and the different potentials necessary for the supply of the Braun tube, of the deflectingvoltage generators, etc.,- maybe tapped at different pointsof said resistance. i

The deflecting voltage generator comprises a motor 39, which drives the shaft 10 which in turn actuates in direct fashion or if desired through the medium of an intermediate gear the apparatus H and I2 producing the deflecting voltages; The apparatus producingthe image deflecting voltage consists of a collector ring [3, which is furnished with a large number of segments l4 insulated one against the other. The segments l4 correspond in number with the number; of lines in the television image to be'produced. The

single segments are connected .with correspond ing points of a resistance 20, which conveniently may be arranged within the ring, and the two ends of whichare connected through the medium of the pick-up rings i5 and i6 and the wipers Hand 8 with the potential source IS. At the single segments Hi there is accordingly a potential, which is equal to the potentials at the different connection points of the resistance 20. The connection points are preferably selected in such fashion that the potential of. the single segments increases in strictly linear form in relation to each other, i e. in such away that. between each two following segments there is normally the same difference in potential. In this manner it is possible without difiiculty to produce an exactly steplike image-deflecting potential.

Now according to the invention the arrangement is such, that it is possible to interchange the connection points of'the singlesegments as desired. It is sufficient, for example, for this purpose to furnish the segments with connection bushes, and to weld on'tothe single connection pointsfof the resistance wires furnished with plugs, in order by simply exchanging the plugs to obtain a desired sequence of the lines, and. accordingly to permit of the reception of transmissions in. cipher, i. e. the reception of transmissions wherein for keeping the transmission secret, in the transmitter the single pictures to be transmitted arescanned in such a way that not adjacent lines arescanned one after the other, for example in such a way that at first there is scanned line 12th, then line 1st, then line 3rd and so on. The sequence of the lines to be scanned being known only to the desired receiver, the reception of the transmission by undesiredreceivers is safely prevented.

Since the adjustment to a certain combination does not call for anything else beyond the changing about of a few plugs, an adjustment of this nature may always be performed without trouble with the requisite speed.

Naturally the adjustment of different combinations may also be performed in other fashion structurally, based on the idea according to the invention.

The image deflecting potential is picked up at the segments I4 by the wiper 2| and passed in direct fashion to the deflecting plates of the Braun tube.

The line voltage generator l2 may consist of a condenser with a stationary plate 23 screened by an earthed casing 22, and a plate 24, which is set into rotation by the shaft l0.

As disclosed by Fig. 5, the side of the casing 22 directed towards the rotating plate 24 possesses a recess 25. The rotating plate 24-as shown in Fig. 6consists of two preferably reniform plates- 26 and 21, which are insulated against each other and are conductively connected with contacts 28 and 29 mounted on the shaft Ill and likewise insulated one against the other. The wiper 30 is connected with the battery 3|, which supplies the line-deflecting potential (i. e., with corresponding points of the transformer arrangement l0) The operation of the arrangement is as follows:

The potential at the stationary plate 23 connected with the deflecting plate of the Braun tube is determined by the size of the particular part of the plate 24 that is not screened off at the respective moment. In the position of the plate 24 shown in Fig. 5 the part 26 is connected to the potential 'source 3| and completely visible. In consequence at this moment there is the maximum deflecting voltage at the deflecting plates of the Braun tube. When the plate 24 additionally rotates in the direction of the arrow the wiper 30 passes from the contact 28 to the contact 29. In. consequence the plate 26 is disconnected from and the plate 21 connected to 3|. The potential at the deflecting plates accordingly drops instantaneously to zero, to increase gradually by the extent to which the now connected plate 21 is rotated into the field of View, etc., etc.

By suitable shaping of the plates Y26 and 21 it is possible to accomplish without difliculty that the potential atthe deflecting increases in perfectly linear fashion, so that an exactly sawtooth deflecting potential is produced.

The adjustment of the phase occurs in the most simple fashion by rotation of the components, i. e., possibly the casing 22 or the wiper 2 I.

-With correct embodiment of the motor ,it is quite possible without difiiculty to keep the reception correct in phase over a relatively long period. v

It is also possible to provide special means for synchronising the motor, for example to provide a Thyratron, which is controlled by the synchronising impulses, and the discharge of which controls the motor 39 by the use of an auxiliary winding or the like. The use of synchronising means of this nature, however, represents a comparatively considerable complication of the arrangement and is not absolutely essential.

The total arrangement may be mounted in a comparatively small casing, which is either screened 01f itself, or the single parts of which are employed as screening means.

One of the essential advantages of the arrangement according t the invention resides in. the high insensitiveness thereof against thermal and mechanical strains.

In Fig. 7 there is shown in perspective a form of embodiment of the arrangement according to the invention.

In the same:

32 is the preferably metallic container, 33 the Braun tube which is arranged somewhat to recede and is protected by the grid 34. 35, 36 and 31 are operating buttons; at 38 there is shown the arrangement for adjustment of the cipher. This device may conveniently be arranged to recede in the apparatus casing. In the recess there is conveniently provided an incandescent lamp, which facilitates the adjustment.

To avoid burning of the luminous screen means are provided, which prevent the cathode my to be switched on before the deflecting circuit begins to function.

Since the deflecting potentials in the arrangement according to the invention are produced by the motor 39, the arrangement may be such that by means of the operating lever merely the motor is connected, and that this itself switches on the cathode ray.

This may be obtained for example by providing on the Wheel of the motor a member, which, for example ametallic brush, upon rotation of the wheel is pressed outwards by the centrifugal force and which in this case presses against a metallic ring surrounding said wheel and being arranged in operative relationship to said member. The metallic member may be connected with the potential source and said ring may be connected to the cathode or to the anode of the Braun tube. Conveniently a spring may be provided attracting said metallic member to said wheel as long as the wheel is not rotated.

Further, the arrangement may be such, that the Wehnelt cylinder can at no time become more positive than the cathode.

In orderto avoid safely any'unnecessary consumption of power, an arrangement may also be provided (for example. a time switch), which stops the arrangement automatically after a certain time when the radio apparatus does not supply the potentials necessary for reception (for example, therefore, when the transmitter is disconnected).

Time switches which may be used for the purpose of the invention are already, however, and form per se no part of the invention.

Preferably the Braun tube is mounted elastical ly in the container and is closed off towards the outside by a wire netting or by a sheet of bulletproof glass.

All of the tubes of the receiver should be mounted elastically for example with the use of holders consisting of rubber and be particularlyprotected against the microphone effect, for example with the use of elastic caps consisting of a metal or of rubber and coating preferably the whole of the glass bulb of the valves.

The wholeof the box containing the Braun tube and the electronic valves as well as the deflecting voltage generator and the other parts of the arrangement should be constructed as far as.

possible to be soundproof. For this purpose all of the parts of the box should be tightly fitting and provided at the inside with a coating of sound proof materialsuch as for example cork.

According to the inventionthe entire arrangement may be arranged in a container, which should not exceed the size of 30.20.15 cm.

I claim:

1. A device for producing deflection voltage variations for a cathode ray beam which is developed in a cathode ray tube comprising a pair of beam deflecting electrodes, a conducting shield member having a rectangular opening therein, a stationary condenser plate positioned at one side of the shield member and opposite the rectangular opening, a second condenser plate positioned at the other side of the shiel d member, said second condenser plate including two separate conducting portions of similar shape and area insulated from each other along a substantially straight line, means for rotating the second condenser plate about an axis normal to the plane of the plate and passing through approximately the middle of the line of separation between the two separate portions of the plate, the axis substantially coinciding with one edge of the rectangular opening in the shield, each of said portions having an arealess than the area of the rectangular opening, a source of potential, means for connecting one terminal of the source of potential to one of the beam deflecting electrodes and to the shield, means for connecting the stationary condenser plate to the other beam deflecting electrode, and means including a commutator for intermittently and alternately connecting the other terminal of the source of potential to the two separate portions of the said second condenser plate.

2. A device for producing deflection voltage variations for a cathode ray beam which is developed in a cathode ray tube comprising a pair of beam deflectingelectrodes, a conducting shield member having an opening therein, the opening being bounded by at least one straight edge of a predetermined length, a stationary condenser plate positioned at one side of the shield member and opposite the opening therein, a second condenser plate positioned at the other side of the shield member, said second condenser'plate including two separate conducting portions of similar shape and area insulated from each other along a substantially straight line of a length substantially corresponding to the length of the straight edge of the opening in the shield, means for rotating the second condenser plate about an axis normal to the plane of the plate and passing through approximately the middle of the line of separation between the two separate portions of the plate, the axis substantially coinciding with the straight edge of the opening in the shield, a source of potential, means for connecting one terminal of the source of potential to one of the beam deflecting electrodes and to the shield, means for connecting the stationary condenser plate to the other beam deflecting electrode, and means including a commutator for intermittently and alternately connecting the other terminal of the source of potential to the two separate portions of the said second condenser plate.

KURT SCHLESIN GER.

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