US2872615A

US2872615A - Cathode ray tube deflection and high voltage apparatus

Info

Publication number: US2872615A
Application number: US525015A
Authority: US
Inventors: Paul M Lufkin; Daniel E Stubbins
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1955-07-28
Filing date: 1955-07-28
Publication date: 1959-02-03
Anticipated expiration: 1976-02-03

Description

Feb. 3, 1.959 PQ M. LUFKIN ET AL 2,872,615

cATHonE RAY TUBE DEFLECTION ,AND HIGH VOLTAGE APPARATUS Filed July 28, 1955 2 Sheets-Sheet 1 PAM MIM/72M j Y ai Feb- 3, 1959 P. M. LUFKIN ETAL 2,872,615

CATHODE RAY TUBE: DEFLECTION AND HIGH VOLTAGE APPARATUS Filed July 28, 1955 2 Sheets-Sheet 2 fa ad t 57 INVENTU 5 ,2 n Mld/4765;(

Mm E. S72/ N5 United States Patent rarice CATH-IODE RAY TUBE DEFLECTION AND HIGH i VOLTAGE APPARATUS Paul M. Lufkin and Daniel E. Stnbbins, Findlay, hio,

assignors to Radio Corporation ofAmerica, a corporation of Delaware Application `lul'y 2S, 1955, Serial No. 525,015

6 Claims. y (Cl. :H5- 27) Ther present invention relates to new and improved apparatus for furnishing both thev high unidirectional potential for a cathode ray tube anode and the electromagnetic energy for causing an `electron beam within such tube to scan a predetermined pattern.

1 More particularly, this invention relatesA to an improvementl in the well-known combination high voltage and deflection output transformer such as is conventionally employed in conjunction with television receiver kine scopes.

Since electromagnetic deflection coils' have a certain amount of inductance, some stored energy is present in the coils at the end of each deflection cycle. It is possible, through the use of' a damping tube or diode, to use a portion of such stored energy for producing a part of the voltage variations employed in deflecting the cathode ray beam during the initialI portion of the next succeeding scanning cycle. Such action is well-known and is termed reaction scanning. The deflection coils also have certain` inherent desirable capacitiesV which, together with their inductance, produce tuned circuits having pre'- deterrnined frequencies. During the go time,4 which is the time of the useful trace of the scanning beam, energy is stored in the magnetic field of the transformer and deflection coils; The energy contained in the coilsis permitted to produce a half cycle of free oscillation'during the llyback time and, at the end of such half cycle of oscillation, the damper diode is employed to control or absorb theV remaining energy, whereby to suppress substantially completely the remaining cycles of oscillation. Since it is desirable that the high voltage or accelerating I potential required for" operation of the kinescope also be derived in an efficient manner, it has become customary tocombine the .functions of deflection and high voltage derivation in a single apparatus in which use is made of the inductive nature of the' deilection circuits.`

That is to say, (most present-day" television horizontal deflection circuits include means such as a power amplitier tube for driving a sawtooth current wave form through atransformer which couples the sawtooth energy to the deflection coils. Through the agency of a voltage stepopwinding, the flyback pulses produced in the circuit inductanc'es Vduring the scanning retrace intervals are applied to a rectifier tube and filtered to aiford a-highunidirectional potential for 4application to the final anode of the kinescope. At the end of the deflection scanning cycle, when the output or power tube is driven `to cutoff, whereby the deflection voltageA source is removed from' the coils, the energy then contained lin the transformer, including the `step-up winding, causes relatively higher frequency oscillation to be set up. Such higher frequency oscillation (as distinguished from the desired oscillation which is employed'in the retrace deflection of the scanning beam) has been thesource of such difficulties in practice as the production of .raster ringing which manifests itself in the production of alternate dark and light vertical bars, on usually the lefthand side of the raster.`

Iiiview of such undesirable effects which result from 2,872,615 Paitented Feb. 3, 1959 erly harnessed whereby to afford increased efficiency in Y both the deflection and highvoltage deriving functions of such apparatus;

It is a primary object of thepresent invention, therefore, to provide new and improved deflection and high VoltageV transformer means for use in high etiiciencydeilecton and high voltage production.

Byl way of background, and as described in the abovecited application, it will be understood that, in the case of the well-known auto transformer arrangement, the damper tube conducts heavily at the end of retrace time. This approximates a short circuit across what may be considered as the secondary winding of the transformer. During the latter portion of, the scanning period, the

horizontal output tubev conducts. heavily, whereby to approximatev a short circuit across what may be considered the primary and secondary portions of the auto transformer. As will be appreciated by those skilled in theart, there exists a leakage inductance between the high voltage step-up winding, (tertiary winding) and the remainingportion of the auto transformer, which leakage inductance is responsible,v at least in part, for the ringing or high frequency oscillation mentioned supra. v

The present invention has, for another of its objects that of providing novel means for controlling the frequency of the ringing which results from the leakage inductance and its associated inherent capacities in such manner as to provide increased high voltage and greater deflection efficiency. A

ln` general, the invention of the cited application of Lufkin et al. provides meansl for controlling the frequency of the described ringing in such manner as to phase the ringing waveform so that the ringing voltage combines with the flyback pulses to increase their amplitude and, secondly, combines with the current through the damper tube in a manner calculated to increasethe amount'of sawtooth current which may be applied to the system by the power tube, whereby to increase the eiciency of the decction system proportionately. ln accordance with thatinvention, such control of the ringing frequency is afforded by spacing the tertiary or step-up winding radially from the concentrically wound primary-secondary windingof the auto transformer, as by means of a cylinder of insulating material of the proper wall thickness. This` spacing, when of the proper value, decreases the frequency of the ringing in an amount sufficient to'phase it correctly so as to aid the ilyback pulses and the deflection current.

In accordance with the present inventiorn'the spacing between the 'concentric primary. and tertiary windings of the transformer is effected through the agency of a corrugated member of insulating material which, by virtue 'of its corrugated configuration, aiords a self-centering action `of the tertiary winding with respect to the primary winding. Moreoyer, improved transformer operation is thus. available-byreason of the circulation of airthrough the openings in the corrugated spaces. Y

As will be appreciated, the present inventionY requires only a sirnpleV change in existing deflection and high voltage transformers in order to bring about'the improved results set forthherein'. Additional objects and advantages of the present invention will become apparent to `persons skilled in the art from a study of the following '3 cuit diagram, a typical television receiver including a combination horizontal deection and high voltage transformer arrangement in which the present invention may beadvantageously employed;

Fig. 2 illustrates certain voltage wave forms to be described;

Fig. 3 illustrates current wave forms useful in describing another aspect of the invention; and

Figs. 4 and 5 are simplified sectional views of a transformer constructed in accordance with the invention.

Referring to the drawing, and more particularly, to Fig. l thereof, block represents that portion of a typical television receiver which includes a radio frequency amplifier, converter, intermediate frequency ampliiier stages and the second detector'. Details of these circuits are well-known to those skilled in the art and need not be described further. Examples of suitable circuits, however, may be found in an article entitled -Televison Receivers, by A. Wright in the March `1947, issue of the RCA Review.

The input terminals of receiver 10 are provided with composite television signals which are intercepted by an antenna 12. These signals are amplified by the receiver and demodulated in the usual manner so that they appear at output terminal 14, which terminal is indicated for connection to the beam intensity controlling electrode of the cathode ray image-reproducing device 16. The video signals demodulated within the receiver 10 are or may be suitably clipped to provide horizontal and vertical synchronizing pulses for application to the sync separator circuit 18 via lead 20. The horizontal sync pulses then appearing at output terminal 22 of the sync separator are applied for synchronization of the horizontal deflection signal generator or oscillator 24, while the vertical synchronizing pulses are applied via lead 26 to the vertical deflection signal generator 28. The output of the vertical deflection generator 28 is conventionally connected for driving the vertical deflection output amplifier 30 which, in turn, drives a suitable sawtooth current of iield Vfrequency through terminals Y--Y and the vertical detiection winding 31.

The output of the horizontal deflection generator 24 is coupled to the control electrode 32 of a horizontal deflection output discharge tube 34. Suitable biasing potential for the discharge tube screen electrode 36 is conventionally supplied from a source of positive potential indicated at terminal 38 as +B through a screen dropping resistor 40 which is, in turn, bypassed to the cathode 42'via a capacitor 44. A self-biasing cathode resistor 46 whose value is chosen in accordance with the desired operating bias for amplifier 34 is connected in the cathode circuit of the tube and is bypassed by capacitor 48. Y

The anode 50 of amplifier 34 is connected to a terminal S2`of an auto-transformer 54 which includes an auxiliary step-up winding 56 connected to the anode 58 of a high-voltage rectifying diode 60. The cathode filament 62 of'a rectifier 60, energized by a winding 63 on the transformer 54, is'connected to ground through a filter capacitor 64, so that high voltage for the nal anode (not shown) of kinescope 16 may be applied to the high-voltage terminal 68. The lower terminus 70 of the auto-transformerV 54 is connected through a B- boost capacitor 72 and a linearity control inductance 74 of a source of +B potential at terminal 76.

Another capacitor, such as that indicated at 78, across which is developed a portion of the B-boost voltage, and which aids in the linearity control action of the inductance 74, is directly connected from the auto-transformer terminal `70 to the +B terminal 76. The horizontal deflection winding 80 of the cathode ray deflection winding 8th of the cathoderay deflection system isconnected in shunt with that portion of the auto-transformer between terminals 79 and 81. `The` damping device which comprises, by way of illustration, the diode 82, is connected in dampingrelation with the yoke winding 80 through the B-boost capacitor 72 and the linearity inductance '74 taken in combination with the capacitor 78. Accordingly, the anode 84 of damper diode 82 is connected with the +B terminal 76 through the linearity inductance 74, while the diode cathode 88 is connected to a suitable point 90 on the auto-transformer.

As thus far described, the apparatus of the drawing is in accordance with conventional practice. Since the operation of reaction-scanning apparatus is well-known, it need not be described in detail here. A fulll analysis of such operation is given, for example, in an article entitled Magnetic Deflection Circuits, RCA Review, September 1947, by O. H. Schade. Briefly, however, it is to be noted that the bias on the horizontal output tube 34 is so adjusted that, during operation, the driving sawtooth waveform 24' which is provided by the horizontal deflection generator, will produce anode-cathode conduction during a period corresponding to only a little more than half the deflection cycle. Hence, it may be assumed that the horizontal output tube 34 is rendered conductive by the sawtooth waveform 24' during only that time between instants t1 and t2, during which interval anode-cathode current will pass from the positive power supply terminal 76 through the inductance 74 and through the diode 82 to the transformer 54. Such current flow induces some deflection voltage and current in the transformer which causes a substantially linear rise in deection current through the yoke winding 80. At time t2, corresponding to the commencement of the retrace interval ofthe deflection cycle, the discharge tube 34 becomes non-conductive and the magnetic eld in the auto-transformer and yoke then collapses, causing oscillation of the primary resonant circuit (i. e., the yoke and its distributed capacitance) at its self-resonant frequency which is normally at least four to five times that of the deflection frequency.

After one-half cycle of free oscillation, the voltage appearing across the horizontal winding 80 is of such polarity as to cause the diode 82 to conduct, thereby damping the energy magnetically stored in the yoke. The direction of the damping current through the diode 82, in accordance with well-known reaction scan ning principles, provides the first portion of the sawtooth through the winding 80, which'portion corresponds to the interval between instants t3 and t4 of the sawtooth 24. By the time t4 is reached, the horizontal discharge tube 34 will have been rendered conductive and this time, by reason of the bias across capacitors 72 and 78the diode 82 will not conduct as heavily, thereby causing most of the horizontal output tube anode current to flow through the auto-transformer section between

terminals

90 and 70.'

Also during `the retrace interval (i. e., between times t2 and t3) the collapse of the magnetic field in the autotransforrner and yoke as above described results in the production of a high, unidirectional pulse across thc transformer tertiary winding 56. The amplitude of such pulse is proportional to the quantity where L is the inductance of the circuit produced by the transformer during the retrace interval, Vthere is additionally produceda 'ringing voltage train following the pulse of avfrrequency` which, is .determined by the usual formula y 1 fwn/Lo where L is the inductance of Vthe circuit and C its capacity, including distributed capacity of the transformer tertiary winding. The high voltage pulse and its associated ringing voltage is illustrated by the wave forms (a) and (b) of Fig. 2, wherein, as may be seen, the high voltage pulse 96 is followed by a ringing voltage 98 having a period equal to T. Normally, as may be noted from a study ofthe prior, art, the ringing voltage has constituted a source of difficulty insofar as its effects upon deflection linearity is concerned. The present invention, as has been set forth briefly, exploits `the ringing voltage in such manner as to increase both the amount of high voltage which mayA be. obtained and the amount of deflection afforded by the circuit.

Referring again to wave form (la) of Fig. 2, it may be seen that the final half cycle of the ringing wave form 98 (i. e., that immediately preceding the second tlyback high voltage pulse 96') is at or near its minimum value. It has -been found through experiment that such phasing of the ringing wave form effectively decreases the amplitude of the pulse 96 as through a process in the nature of algebraic subtraction of the voltages. lIt has been found by the present applicants that, by properly phasing the ringing wave form 9S with respect to the commencement of the retrace time, it is possible to increase the amplitude of the ensuing high voltage pulse. Specifically, such control of the phasing of the ringing wave form 98 is afforded by the present inventionthrough means for controlling the period of the ringing wave form and changing it vfrom the period T of wave form (a) tothe longer period T; of wave form (b) in Fig. 2. Where the period T is of the proper value, the nal portion of the ringing voltage train 93 will be at or near its maximum value immediately preceding the commencement of the retrace period TT. With the ringing voltage phased as in wave form (b) of Fig. 2, it effectively adds to the high voltage pulse 96" to increase its amplitude.

As those skilled in the art will appreciate, it is neces sary to maintain the duration of the retrace interval at its proper Value, so that any` arrangement for changing the period of the ringing voltage should be one whichtproduces noY appreciable difference in the retrace time. In particular, as described in the Lufkin et al. application, the period of the ringing voltage train may be increased from its value T to the longer value "1"by decreasing the ringing frequency and, specifically, by increasingthe leakage inductance between the tertiary winding 56 andthe primary winding 4of the transformer which may be considered as that part betweenterminals `52; and 79. Whilel itwould be possible to edectlsuch a change in the ringing frequency, for example, by increasing the number of turns of the tertiary coil, therebyinereasingthe leakage inductance, such an arrangement would be undesirable since it would necessarily increase the' distributed capacity of `the tertiary windingand, additionally, and even more significantly, would change. the turns ratio through 'which the existing' tertiary capacity lclading'` is` reflected across the deliection winding Sand, since this transfer is proV portional'to theV squarev ofthel number of turns,` the retrace time would undesirably be substantially increased. Also, while itis possiblel to increase the ringing period by adding capacity to the rectifier end of the tertiary.l winding, such an arrangementis impractical sincel it would increase the. retrace timeA andy lower the amplitude of the yback pulse.

As may be foundin basic Vtext books dealing with matters of the present variety, the leakage inductance,'between` two concentric windingsy of a transformer is proportional tothe quantity .y X l-9 henry t where.c isthe length of a turn midway between innere, most and outermost layers, a is the distance between the two windings, conductor to conductor, d1? and d2 are the build-ups of the two windings (all of the foregoing dimensions being expressed in inches) and N is the number of turns of the winding to which the leakagev inductance is referred. Since the build-up d1 of the primary winding of the transformer 54 in'Fig. 1 is normally fixed by such considerations astheprimary impedance direct current resistance, flux density inthe core and minimum primary to secondary leakage inductance, the present invention affords a control of the leakageinductance of the tertiary winding with respect to the rest of the winding by changing the parameter a, namely, the distance measured radially between the windings. As may be determined from the foregoing expression for leakage inductance, the leakage inductanceV is therefore increased as a direct function of -theY spacing between the tertiary winding and the remainder of the transformer and, secondarily, by the increase in the mean winding diameter (referring to the parameter c). At the same time, as will be understood from the following formula, the distributed capacity of the tertiary winding is increased only by the increase in the mean diameter of the tertiary winding:

`tarad where c is the mean length of turn of the winding; l

is the length of winding (i, e., wire traverse); d is the distance between layers (all in inches); T is the number of 'layers of wire in the winding; and k is the average dielectric constant of the insulation material. Since the turns ratio is not increased, however, and since the change in the radial spacing parameter a producesonly a small amount of additional capacitive loading,ythe present invention affords the desired increase in the ringing fre# quency without changing the length of retrace time appreciably.

Fig. 4 illustrates' by way of a simplified, vertical sectional view, a combination deflection and Vhigh voltage transformer such as that illustrated schematically in the circuit diagram of-Fig. l and, in the interest of clarity, reference numerals identicaltto thoseused in Fig, 1 designate corresponding portions of the structure of Fig. 4. In Fig. 4, the transformer 5d includes a first winding from terminal 52 to the terminal 79 which comprises the primary winding ofl the transformer. This winding isl cylindrically arranged about a cylinder 169 formed of a suitable insulating material. An iron core in the form of two C-shaped members 102 and 164 is provided inl a conventional manner. The ends of the C-shaped membersA ,102 and 1104 within the insulating cylinder or coil form 10i) may be spaced, as shown,` for the purpose of eliminating saturation due to plate` current (D. C.) flow ing from terminal to terminal 52. The tertiary winding 56 starts at the point 52 and ends at the lead 106 which is adapted for connection to the anode 58 of the high voltage rectifier diode4 6i! and is suitably coated with insulating material 167. The tertiary winding S6 is wound concentrically with respect to the primary winding and, in v accordance with thepLufkin ety al. copending application,v isV spaced therefrom a predetermined distance a.

Normally, as will be recognized by those skilled, inthe art, the aim of transformer designers `in the past has been that of winding the tertiary or step-up Winding as close Ito the primary winding as is possible since the concern was with reducing the leakage inductance as much as possible in, an effort to decrease the ringing. in accordance `with the cited application, however, the tertiary winding 56 is spaced from the primary winding by a predetermined distance a for the express purposerof increasing the `leakage inductance between the two windings in such manner as to increase the period `of the ringing voltage attributable Z5. tothe leakageY indilctance, whereby to phase the ringing` voltage with respect to the commencement of the retrace interval as shown in waveA form' (b) of Fig.` 2. Novel means for spacing thewindings in accordance with the present invention will be described in detail hereinafter so that it will be understood that the preceding discussion deals with the general effect of the spacing of the windings as disclosed in the cited application. The specific values of the various physical dimensions of the transformer windings will, of course, vary as a function of the desired amplitude of deflection and the value of the high voltage to be produced. In the interest of providing a specific example, however, the following dimensions of an actual transformer built in accordance with the invention for use in a 70 deflection and 17 kilovolt high voltage arrangement are herein presented, as follows:

Inner diameter of the primary winding=0.550 (i. e.,

,t outer diameter of the coil form l100) Outer diameter of primary winding=l.057"

Inner diameter of tertiary winding S6=l.2l4"

' From the foregoing, it may be seen that the spacing increases the leakage inductance between the tertiary winding and the primary winding of the transformer 54 in such manner as to decrease the ringing frequency. Such frequency decrease may be selected, moreover, to be of the proper amount for phasing the ringing voltage as shown in wave form (b) of Fig. 2 so that the ringing voltage is at or near its maximum peak value at the commencement of the retrace interval.

vAlthough the following does not specifically constitute a part of the present invention, it should be noted in the interest of completeness of description that the ringing effect upon the deflection linearity is minimized in accordance with the circuitry of Fig. l by virtue of the connection of the lower end of the horizontal deflection winding 80 at the point 79 on the transformer 54, which point is spaced in potential from the bottom ofthe winding (terminal 70) or A. C. ground. This connection of the deflection winding at a higher impedance point than ground isa Well-known expedient for reducing the effects of ringing upon deflection linearity and is effective in the case of the present invention wherein the leakage inductance between the tertiary and primary windings of the transformer is intentionally increased for the purposes set forth.

Another important advantage afforded by the spacing between the transformer windings is that of increasing the efficiency of the deflection circuit itself. Briefly, this action is accomplished by virtue of the fact that the spacing between the tertiary and primary4 windings of the transformer also changes the phase of the leakage inductance ringing voltage which is coupled into the damper tube circuit. Specifically, and as is Well-known, the amount of horizontal driving voltage which may be impressed upon the deflection transformer 54 by the horizontal output tube 34 is limited by the damper tube current. That is to say, maximum permissible drive is normally attained when the damper tube current is reduced to zero in the vicinity of the middle of the scanning line, such cessation of damper tube conduction being manifested by a bright vertical line in the'center of the kinescope raster. As stated above in connection 'with the general description of the deflection circuit operation, it is the damper tube current (between times t3 and t4) which furnishes approximately half of the deflection energy in each horizontal line scan. It has been found that, for optimum performance of such a reaction scanning arrangement to be realized, it is necessary for the driver tube 34 to furnish an excess of current to the deflection circuits, so that the damper tube may conduct continuously during the go time.

A typical current wave form through a damper tube such as the tube 82 in Fig. l is illustrated by wave form (a) VofnFig. 3, in which'the go time or scanning period is designated as TBL V"'By virtue 'of the'` connectionof' the damper diode as shown, current therethrough is in the negative direction as is necessitated by the requirement that the damper current deflect the electron beam within the kinescope to the opposite side of its central position from that direction ,in whichthe driver tube current detlects it. The dotted line, portion 112 of the damper current wave form (a) of Fig. 3 represents the current for a given amount of drive from the horizontal outputtube 34. As amount of drive is increased, the current through the damper tube also increases as indicated by the solid line portion 114 of the wave form. The rippled portions of the wave form are the result of the ringing energy from the leakage inductance of the transformer which is coupled into the damper tube circuit. The minima or peaks 116 of the damper tube current wave form are at the zero reference line and indicate damper tube cutoff, which constitutes the limiting condition for the amount of drive which may be furnished by the tube 34. Since the efllciency of the circuit is generally proportional to the amount of drive which may be successfully applied to the circuit, it is desirable to increaseY the current through the damper tube (i. e., in the negative direction) so that the peaks 116 do not reach zero or, stated otherwise, so that the damper tube is not cut off during the middle of the scanning line.

The present invention performs the desirable function of increasing the damper tube current during the middle portion of the scanning line by so phasing the ringing voltage train of the leakage inductance that it adds to the damper tube current in such manner as to increase that current (in its negative direction) by adding a negative half cycle of the ringing energy to the damper tube currentl during the central part of the scanning Vline interval, thereby preventing the damper tube current from being cut off. The phasing of the ringing voltage as accomplished in the interest of increasing the amplitude of the highvvoltage pulses has been found to be substantially the proper phase for increasing the damper tube current during the middle of the scanning line, and as illustrated in'wave form (b) of Fig. 3. That is to say, the spacing of the tertiary 4winding 56 from the primary -Winding of the transformer 54 which increases the leakage inductance therebetween whereby to increase the period of the ringing voltage-.train provides a negative half cycle of ringing voltage near the peaks of the damper current wave form of Fig. 3 (a) so that the resultant damper current is changed to that shown by wave form (b) of Fig. 3 wherein the peak 116 is more negative than the zero reference. Thus, the amount of drive which may be furnished by the horizontal output tube 34 is increased so that greater deflection efficiency is possible.

In accordance with the present invention, a novel spacing device is afforded, as indicated by reference numeral in Figs. 4 and 5. Specifically, the spacing device comprises a corrugated member of insulating material and may be formed, for example, of a corrugated strip of such material as kraft paper, iishpaper or the like. That is, the strip of insulating material is shaped with alternate ridges and valleys of a generally sinusoidal configuration so that it may be curved into cylindrical form to fit between the primary winding of the transformer and the secondary lwinding, as shown, with its corrugations parallel to the common axis of the windings.

Since the transformer windings are ordinarily layer woundV on separate arbors, the outer diameter of the primary winding is substantially constant and the inner diameter of the tertiary winding is also fixed. Thus, the critical dimensions of the windings, insofar as the present l invention is concerned, are fixed prior to assembly of the windings. The corrugated spacer element 120 serves, when disposed between the two windings, to center the tertiary'winding about theprimary winding, that is, to maintain a concentric relation between the two windings.

, The centering action described stems from the fact that the corrugations in the strip of insulating material im- Y9 part` to the strip a springiness whichl causes .the A strip to urge the teritiary winding outwardlyiequally alongvall radii of the windings. By virtue of the self-centering action of the novel spacing element of the present in- Vention, the requisite precision of a cylindrical spacer such as that used heretofore is obviated.

In addition to the structural simplification afforded, the present invention also provides, as has been mentioned, an improvement in the operation of the transformer. That is, the temperature of a transformer rises during operation as a result of 12R copper losses and, at times, to the point where it is troublesome and may even require additional copper in the, interest of reducing such losses. The corrugated spacer strip 12) which is located between the primary and tertiary windings permits the circulation of air` between the windings so that the operating temperature of the transformer` is appreciably lowered.

From the foregoing, it will be understood that the present invention provides a novel combination high voltage and deflection transformer in which the high voltage step-up winding is spaced radially from the primary winding by a corrugated insulating element and by an amount sufficient to increase the leakage inductance between the two windings in s uch manner as to change the phase of the leakage ringing voltage train whereby to (l) increase the amplitude of the high voltage pulses and (2) increase the amount of drive which may be furnished to the deflection circuit. f

Having thus described our invention, what we claim as new and desire io secure by Letters Patent is:

1. A deflection and high voltage transformer for use in conjunction with a cathode ray tube and adapted to couple energy from a deflection amplifier to an electromagnetic deflection winding and to a rectifying circuit for producing a high unidirectional potential for application to an electrode of such tube, said transformer comprising: a cylindrical primary winding adapted for connection to both such amplifier and to such deflection winding; a cylindrical winding serially connected to said primary winding and adapted to couple energy to such rectifying circuit, said second winding being concentric with and around said primary Winding; and a spacing member of insulating material disposed between said second and primary windings for providing a leakage inductance therebetween substantially greater in value than that available in the absence of a space, said spacing member being corrugated with its corrugations parallel to the common axis of said windings.

2. VA combined deflection and high voltage transformer for use in conjunction with a cathode ray tube, said transformer comprising: a first transformer winding having an input terminal adapted for connection to a source of deflection energy and a pair of output terminals for connection to an electromagnetic deflection winding; a second transformer winding electrically connected serially with and physically concentric with respect to said first vwinding in such manner as to be in energy transfer relationship therewith, said second winding having an output terminal forY connection to a rectifying circuit of the type adapted to rectify recurrent fiyback voltage impulses produced in said transformer whereby to produce a high, unidirectional potential for application to such cathode ray tube; and means for spacing said second winding radially outwardly from said first winding a distance sufficient to produce a leakage inductance between said first and second windings greater than that available in the absence of said spacing means, said spacing means comprising a generally cylindrical element disposed between said windings and corrugated with its corrugations parallel to the axis of said windings.

3. A combined deection and high voltage transformer for use in conjunction with a cathode ray tube, said transformer comprising: a first transformer winding having an input terminal adapted for connection to a source of deflection energy` and a pair of output terminals for comV nection to an electromagnetic deflection winding; a, sec-v ond transformer winding electrically connected serially with and physically concentric with respect to said rst winding in such manner as t0 be in energy transfer rela-` tionship therewith, said second winding having an output terminal for connection to a rectifying circuit of the type adapted to rectify recurrent flyback voltage impulses produced in said transformer whereby to produce a high, unidirectional potential for application to suchcathode ray tube, said transformer having inherent capacity whereby to form a resonant circuit of such character as to produce ringing of a certain frequency; and means for spacing said second winding radially outwardly from said first winding a distance sufcient to increase the leal:- age inductance between said first and second winding by such an amount as to decrease said certain frequency by a predetermined amount, said spacing means comprising a strip of corrugated insulating material disposed between said rst and second winding with its corrugations arranged accurately.

4. A combined deflection and high voltage transformer for use in conjunction with a cathode ray tube, said transformer comprising: a first transformer winding having an input terminal adapted for connection to a source of deflection energy andv a pair of output terminals for connection to an electromagnetic deflection winding; a second transformer winding electrically connected seriali' with and physicaily concentric with respect to said first winding in such manner as to be in energy transfer relationship therewith, said second winding having an out- Y put terminal for connection to a rectifying circuit of the type adapted to rectify recurrent fiyback voltage impulses produced in said transformer whereby.' to produce a high, unidirectional potential for application to such cathode ray tube, said second winding having inherent capacity; leakage inductance between said second winding and said first winding of a certain value forming a resonant circuit with said capacity whereby ringing is produced at a given frequency determined by the values of said leakage inductance and said inherent capacity; and means for spacing said second winding radially fromrsaid first windmg by a predetermined distance such that said leakage inductance is increased in an amount sufficient to decrease said given ringing frequency by a predetermined amount, said spacing means comprising a strip of insulating material having a plurality of transverse corrugations and located between said first and second transformer windings with said corrugations parallel to the common axis of said windings,

5. A combined deflection and high voltage transformer for use in conjunction with a cathode ray tube, said iransformer comprising: a first transformer winding havmg an input terminal adapted for connection to a source of deflection energy and a pair of output terminals for connection to an electromagnetic deflection winding; a second transformer winding electrically connectedserially with and physically concentric with respect to said first winding in such manner as to be in energy transfer relationship therewith, said second winding having an output terminal for connection to a vrectifying circuit of the type adapted to rectify recurrent ffyback voltage impulses produced in said transformer whereby to produce a high, unidirectional potential for application to such cathode ray tube, said second winding having inherent capacity; leakage inductance between Vsaid second winding and said first winding of a certain value forming a resonant circuit with said capacity whereby generally sinusoidal ringing is produced at a given frequency determined 'oy the values of said leakage inductance and said inherent capacity, said given frequency being such that said ringing is in a certain phase relationship with respect to such flyback impulses; and means for spacing said second winding radially from said first winding by a predetermined distance Vsuch that said leakage inductance is increased in an amount suiiicient to decrease said given frequency byra predetermined amount whereby to alter said phase relationship between said ringing and such yback inipulses,said spacing means comprising a generally cylindrical member of corrugated insulating material arranged between said first and second windings such that said corrugations exert force radially against said rst and second windings.

6. A combined high voltage and deiection transformer for use in conjunction with a cathode ray tube reaction scanning circuit of the type including driver means for furnishing a saw-tooth current waveform during a portion of the scanning time and a unilaterally conductive damper device for furnishing deflection current during the remainder of the scanning time, and in such manner that such damper device current reaches a minimum value 'at a certain point in the scanning cycle, said transformer comprising: a first transformer winding having an input terminal adapted for connection to such driver means, a pair of output terminals for connection to an electromagnetic deiiection winding; and a terminal for connection to such damper device; a second transformer winding electrically in series with and physically concentric with respect to said first winding in such manner as to be in energy transfer relationship therewith, said second winding having an output terminal for connection to a rectifying circuit of the type adapted to rectify recurrent flyback voltage impulses produced in said transformer whereby to produce a high, unidirectional potential to such cathode ray tube, said second winding having inherent distributed capacity;l leakage nductance between said second winding and said first winding of a certain value forming a resonant circuit with capacity whereby generally sinusoidal ringing is produced at a given frequency determined by the values of said leakageV nductance and said inherent capacity, said given frequency being such that said ringing is in a certain phase relationship with respect to such damper current minimum value; and means for spacing said second winding radially from said first winding by a predetermined distance such that said leakage nductance is increased by an amount sutiicient to decrease said given ringing frequency by a predetermined amount whereby to alter said phase relationship between said ringing and such damper current, said spacing means comprising a corrugated member of non-magnetic material located between said first and second transformer windings and of sufficient springiness as to center the outer one of said windings about the inner one of said windings.

References Cited in the file of this patent UNITED STATES PATENTS 667,996 Schwedtmann Feb. 12, 1901 772,288 Neall Oct. 1l, 1904 2,207,777 Blain July 16, 1940 2,499,065 Heppner Feb. 28, 1950 2,602,035 Camilli July l, 1952 2,665,393 Bocciarelli Ian. 5, 1954 2,710,947 Gaston June i4, 1955