ZOPPAS (ZANUSSI) Z26 COLOR ELECTRONIC CHASSIS BS222 BS223 CRT TUBE ITT (SEL) A67-150X

A67-150X delta gun tube from ITT with Narrow nech technology.

ALL colour television receivers in yr 1971's  production in the European continent  were employing a shadowmask tube with a deflection angle of 90°. The manufacturers of colour tubes have however in their wisdom decided to develop 110 tubes, on the grounds that the increase in complexity of the scanning requirements for such tubes is more than justified by the resultant saving in cabinet depth even though this saving is only of the order of a few inches. It is of increase in the deflection angle will make the precise control of the three electron beams more difficult, thus increasing the scanning, convergence, purity and focusing errors.
To add to the general confusion in this field at present there are two different 110' systems, backed by Philips and ITT respectively, which are contending for the grand prize of acceptance by the receiver manufacturers.
The loser in this contest will be in a sorry state indeed. Philips are advocating the use of a wide neck 110' tube ("wide neck" in this connection means that the tube neck and the electron gun dimensions are the same as in a 90° tube) with saddle yoke scan coils and a single transistor line output stage. This system suffers from several disadvantages. The saddle yoke scan coils are of the type used in monochrome receivers. with the windings "flared" up the bowl of the tube and therefore not likely to give very precise scanning. Due to the design of the tube and the scan coils highly complex dynamic convergence circuitry was required : while a few potentiometers and variable inductors are sufficient to achieve convergence on a 90' tube, on this thick -neck
type of 110 ° tube it is necessary to incorporate transistors in the convergence circuitry and extra controls for corner convergence. Furthermore the potential required to focus the tube varies considerably over the scanning range so that dynamic focus circuitry is necessary imagine the problems involved in varying the 5kV focus potential at line rate! The desirable feature of the Philips 110° time base circuitry was  the simplicity of the line output stage which employs a single transistor and is said to be more reliable than earlier two -transistor circuits. ITT's approach to the problem was altogether different and was shown in earlier apparates. A narrow neck 110° tube is used (type A67 -150X), the neck of this being little larger than that of a conventional 100° monochrome tube. Miniature, closely spaced electron guns are incorporated in this and thus the three electron beams are closer together from the very start and require less convergence in fact a relatively simple passive convergence circuit can be used. To ensure that the scanning is precisely controlled a new type of deflection yoke is employed. The construction of this is toroidal (see Fig. 1) and both the line and field coils are similarly wound on it. At first sight the ITT circuit appears to be the more attractive proposition but it must be pointed out that the narrow neck tube was not entirely proven and due to the miniaturisation of the electron -gun assembly there may be cause to suspect its reliability (indeed).
Nonetheless it seems likely that thyristors will be widely used in both colour and monochrome timebases in the further 70's years so it is worthwhile understanding how they work under the obsolete technology aspect ;

TOROIDAL ELECTROMAGNETIC DEFLECTION YOKE:A toroidal deflection yoke is provided for a delta gun shadow mask color television picture tube. The wire distribution of the horizontal and vertical deflection coils is determined by selecting a minimum number of design parameters in the form of angular distributions of windings which can be varied for producing a deflection yoke which yields optimum performance in electron beam convergence and registration.

1. A toroidally wound deflection yoke for a delta gun shadow mask color television picture tube for providing convergence of the beams in the corners of a raster displayed on said picture tube, comprising: 2. A toroidally wound deflection yoke as defined in claim 1 wherein said first and second angular segments are different whereby the conductor distribution density is higher in that portion of the quadrants wherein said first and second segments overlap than in that portion of the quadrants wherein said angles do not overlap. 3. A toroidally wound deflection yoke as defined in claim 2 wherein the angular separation of said convolutions of wire extending around said perimeter through said first angular segment is equal to the angular separation of said convolutions of wire extending through said second angular segment. 4. A toroidally wound deflection yoke as defined in claim 3 wherein said core is a ferrite core. 5. A toroidally wound deflection yoke as defined in claim 4 wherein said yoke includes a grooved end ring located at the front portion of said core, said grooves having an angular separation equal to said angular separation of said convolutions of wire wound around said core. 6. A toroidally would deflection yoke for a delta gun shadow mask color television picture tube for providing convergence of the beams in the corners of a raster displayed on said picture tube, comprising: 7. A toroidally wound deflection yoke for a delta gun color television picture tube, said yoke including horizontal and vertical coils wound on a toroidal core: 8. A toroidally wound deflection yoke according to claim 7 wherein said one of said coils is a vertical deflection coil and the other of said coils is a horizontal deflection coil. 9. A toroidally wound deflection yoke for a delta gun color television picture tube, said yoke including horizontal and vertical coils wound in two layers on a toroidal core: 10. A toroidally wound deflection yoke according to claim 9 wherein said one of said coils is a vertical deflection coil and the said other of said coils is a horizontal deflection coil.

Description:

BACKGROUND OF THE INVENTION

This invention relates to electromagnetic deflection yokes and particularly to a toroidal deflection yoke for use with a delta gun shadow mask color television picture tube.

Heretofore, deflection yokes for television receivers have been wound utilizing one of two general methods--toroidal winding and saddle winding. While a yoke made by the toroidal winding method requires less complicated, less costly manufacturing tools as well as a shorter length of active conductors (e.g., less wire) than a comparable yoke made by saddle winding, use of toroidal wound yokes has been confined to monochrome and so called "in-line gun" color television picture tubes. In the case of the commonly used delta gun, shadow mask color television tube, saddle coils have been employed for both horizontal and vertical deflection windings to satisfy the exacting convergence and registration (purity) requirements of yokes for such tubes. Particularly with regard to large screen delta-gun picture tubes utilizing relatively wide deflection angles such as 110°, the difficulty of maintaining satisfactory beam convergence and color purity in the corners as well as the center of the picture tube has required the use of relatively complex dynamic convergence correction circuitry including dynamic blue lateral convergence waveforms to compensate for coma aberrations in the horizontal yoke coil as well as requiring relatively complex yoke driving circuitry incorporating a dynamic difference waveform resulting in an unbalance of current in each half of the horizontal winding, the unbalance being proportional to the product of horizontal and vertical scan current.

It is an object of this invention to provide a toroidally wound deflection yoke having a minimum number of design parameters for producing a yoke yielding acceptable registration and convergence of the electron beams of a delta gun shadow mask picture tube.

It is another object of this invention to provide a yoke having improved electron optical performance without requiring a difference current driving circuit or dynamic blue lateral convergence correction.

A deflection yoke is provided for a delta gun shadow mask picture tube. The yoke comprises a pair of horizontal and vertical deflection windings wound toroidally around a generally conically shaped ferrite core, the inside surface of which generally conforms to a flared portion of the picture tube. Each of the vertical and horizontal windings comprises symmetrical portions in each of four quadrants of the yoke, the quadrants being defined by the vertical and horizontal deflection axes. Each portion comprises at least convolutions of conductors having a first predetermined angular separation from each adjacent conductor in a layer extending throughout a first angular segment along the perimeter of the toroidal yoke from a line of symmetry and convolutions of conductors having a second predetermined angular separation from each adjacent conductor in a layer extending throughout a second angular segment along the perimeter of the yoke from the same line of symmetry. Overlapping convolutions provide a desired conductor cross-sectional distribution for achieving acceptable registration and convergence of the electron beams.

In another embodiment utilizing two layers of conductors for forming the horizontal and vertical deflection coils, in each quadrant the yoke conductors in the first layer extend continuously over first and second angles from the respective axes to form first portions of the horizontal and vertical coils. Conductors in the second layer extend over a first angle, are separated over a second angle and extend over a third angle measured from one axis for forming other portions of one of the coils, and conductors extend over a fourth angle measured from the other axis and within the separation of the aforementioned second angle for forming further portions of the other of the coils, the respective portions in both layers of the four quadrants being interconnected for forming the horizontal and vertical deflection coils.

For a more complete disclosure of the invention reference may be had to the following description which is given in conjunction with the accompanying drawings of which:

FIG. 1 is a view, partly broken away and partly in section, of a delta gun shadow mask picture tube and a toroidally wound deflection yoke according to the invention;

FIG. 2 is a perspective view of the toroidally wound deflection yoke of FIG. 1;

FIG. 3 illustrates the variable design parameters utilized in determining the conductor distribution of the yoke;

FIG. 4 illustrates a typical winding distribution at the rear of a toroidally wound yoke according to the invention;

FIG. 5 is a partial view illustrating a typical winding distribution at the front of a toroidally wound deflection yoke according to the invention;

FIG. 6 is a schematic representation of the vertical and horizontal windings of the toroidal yoke illustrated in FIG. 4;

FIG. 7 illustrates a winding distribution of conductors at the rear of another toroidally wound yoke embodying the invention; and

FIG. 8 is a schematic representation of the vertical and horizontal coil windings of the toroidal yoke illustrated in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a toroidally wound deflection yoke 20 mounted adjacent the flared bulb section of a delta gun shadow mask tube 11. Tube 11 comprises an evacuated glass envelope 12 having a faceplate 13 at the front viewing portion of the picture tube. Red, blue and green phosphor dots 14 are disposed on the inside surface of the faceplate 13. Mounted within picture tube 11 is a shadow mask 15 having apertures 16. The rear portion of picture tube 11 contains delta electron gun structure 17, the three beams from which are directed along the tube 11 and through apertures 16 to excite the color phosphors 14.

A toroidally wound deflection yoke 20 encircles the flared bulb section of picture tube 11, the inside surface of which yoke generally conforms to the contour of the flared bulb section and is mounted adjacent the flared bulb section. Yoke 20 comprises approximately conical ferrite core 22 having circular cross section around which are toroidally wound conductors 21 (see FIG. 2). Mounted around and adjacent the rear and front portions of ferrite core 22 are grooved rings 23 and 24, respectively. The rings may be made of plastic, for example. The grooves in rings 23 and 24 serve to maintain the desired spacing between the toroidally wound wires. Current in that portion of conductors 21 conforming to the inside surface of ferrite core 22 produces the magnetic field for deflecting the electron beams horizontally and vertically to scan a raster on the faceplate 13. The return portions of conductors 21 are stretched between the front and rear rings 24 and 23 on the outside of core 22.

FIG. 2 is a perspective view of yoke 20 illustrating grooves 25 in the front plastic ring 24. The grooves are spaced equally distant from each other around the front surface of ring 24. In one illustrative embodiment, the spacing of the grooves is 1°. It is to be understood that the rear ring 23 fitted over the rear portion of core 22 also may contain the grooves spaced at equal angles from each other around the rearmost surface of ring 23. In the illustrative embodiment, the grooves or rear ring 23 are spaced every 2°. Also illustrated in FIG. 2 are a number of convolutions of conductors 21 extending through the core 22 and conforming to the inside surface thereof. The return portion of conductors 21, although not shown, is stretched between front and rear grooved rings 24 and 23 as illustrated in FIG. 1. The conductors 21 are toroidally wound around core 22 with conventional apparatus of the type presently employed for winding toroidal yokes. A first layer or course of conductors 21 is wound around core 22 such that the conductors occupy every other groove on the front grooved ring 24 and, in the illustrated embodiment, occupy every groove on the rear ring 23. Thus, each conductor of the first layer is spaced 2° from the next adjacent conductor of that layer. A second layer or course of conductors 21 is then wound around the core 22 such that the conductors of the second layer fill the remaining grooves of front grooved ring 24 and overlap portions of the first layer at the rear ring 23 (see FIG. 3). Thus, each of the first and second layers will have conductors 21 spaced 2° apart around the core 22. Conductors of the first layer are offset from adjacent conductors of the second layer by 1°. The yoke will then appear to contain conductors spaced-apart 1° from adjacent conductors.

The term "layer" as used herein refers to that portion of a conductor which is wound around the core 22 in one complete circumferential traverse (360° ) of the core 22 by the conductor wire.

Once the two layers of conductors have been wound, separate horizontal and vertical coil windings are formed by cutting, peeling, and interconnecting appropriate conductors of the two 360° layers in a manner to be described subsequently.

FIG. 3 illustrates the angular distribution of conductors is the same at each cross section at any point along the longitudinal (Z) axis of core 22. Core 22 of FIG. 3 is shown to be segmented by X- and Y-axes 26 and 27 into four quadrants indicated by the numerals I, II, III and IV. Conductors 21a form a first winding of conductors as described in connection with FIG. 2 and conductors 21b form a second winding of conductors also described in FIG. 2.

For the purposes of describing the invention which is directed to the distribution of windings around core 22, only the distribution of wires within quadrant I, bounded by the X- and Y-axes, will be described. It is to be understood that the windings in each of the quadrants I, II, III and IV are similar because the quadrants are symmetrical.

Illustrated in quadrant I OF FIG. 3 is a layer of conductors 21a extending from the X-axis through an angle θ ₁ and a second layer of conductors 21b extending through an angle θ ₂ from the X-axis. In this embodiment, the conductors 21a and 21b have the same arcuate spacing. Each conductor the quadrants of the toroidal deflection yoke contains both vertical and horizontal windings. The method of determining the distribution of conductors for each of these windings is similar so the invention will be described in connection with FIG. 3 with regard to the general case of determining conductor distribution. In designing the toroidal deflection yoke the diameter and length of the yoke (i.e., the core 22) once initially selected, are not regarded as variables.

It has been determined that, for each of the horizontal and vertical deflection windings, acceptable registration and convergence can be obtained by distributing conductors for each such winding in a first layer along an angular segment θ ₁ and in a second layer along an angular segment θ ₂ with respect to a reference axis in each quadrant. The angles θ ₁ and θ ₂ for each of the horizontal and vertical deflection windings may be determined by arbitrarily selecting a plurality of sets of values of such parameters, winding yokes according to such selected values, measuring resultant convergence and/or registration errors at the faceplate of a picture tube, and by mathematical analysis, calculating values for such parameters whereby the specified errors are minimized. It should be noted that several performance factors can be optimized by varying the minimum parameters, but since convergence is affected most by conductor distribution, it will be shown how to determine the optimum parameters with special attention being given to minimizing convergence errors.

Convergence errors can be minimized by manipulating only four parameters (θ _1V , θ _2V , θ _1H , θ _2H ), and these same parameters completely describe the conductor distribution of the yoke. This fundamental relationship between yoke performance (minimum misconvergence) and conductor distribution is expressed by the following general equation:

in which f is the convergence error under consideration and the angles are considered as independent variables. A linear approximation can be made such that for small misconvergence errors f and Δf the partial quantities of equation (1) may be replaced by constants, and a linear equation, as follows, will be valid in the vicinity of the various angles: (2) f= afθ 1H + bfθ _2H + cfθ _1V + dfθ _2V + ef

in which the constants are af, bf, cf, df and ef, ef being a constant of integration.

The five constants of equation (2) can be determined by selecting five sets of angles (θ _1H , θ _2H , θ _1V , θ _2V ), winding five corresponding yokes, measuring the resultant convergence error (f) produced by each such yoke and substituting the parameter values into five independent equations as specified by equation (2). The first set of θ angles selected are assumed. Toroidal yokes are easily wound on conventional toroidal coil winding apparatus so the winding of a plurality of yokes in determining an optimum winding distribution is practical. Therefore, the error f associated with each yoke is measured on the faceplate of the picture tube on which the yoke is mounted, and the five linear equations (2) are solved for the constants. It may be desirable to set up more than five yokes so that the influence of any measurement error is minimized. In this situation a least square error solution is obtained to yield the correct constants. The constants obtained are then used to determine the θ angles of equations (2) such that f (the error) equals zero. A second set of yokes are then wound having the angular conductor distribution extending over the θ angles derived from the last operation. This process may be repeated, using the derived data from one set of yokes as the design data of a succeeding set of yokes until the optimum performance (minimum misconvergence) conductor distribution is achieved. Such a repeating process is known as a recursion scheme. It is essential in designing a yoke to solve simultaneously for minimization of a multitude of convergence errors in which case the above scheme may be readily extended to accomplish this by the use of matrix equations.

Referring now to FIG. 4, a typical conductor distribution at the rear of the toroidal yoke is shown. The yoke is shown divided into four quadrants I, II, III and IV by horizontal and vertical deflection axes 26 and 27. The conductor distribution in each of the quadrants is identical. For convenience, the conductors of the horizontal deflection winding are indicated by X's and the conductors of the vertical winding are represented by circles. The number of conductors shown are illustrative only and it is to be understood that in actual practice the conductors would be smaller and greater in number. Referring generally to FIG. 4, it can be seen that there is a first layer of conductors 21a wound around the core 22 and a second layer of conductors 21b similarly wound around core 22. Conductors 21a are wound such that they are spaced 2° from each other. This spacing is maintained by the use of the grooved rings described in connection with FIG. 2. The second layer comprising conductors 21b is wound such that the conductors 21b lie in the grooves formed by conductors 21a of the first layer. Thus, the spacing of conductors 21b is also 2° but the entire second layer is offset 1° from the first layer.

In quadrant I of FIG. 4 the distribution of horizontal conductors is illustrated. This distribution comprises a first number of conductors spaced-apart 2° and extending through an angle θ _1H and a second number of wires spaced-apart 2° and extending through an angle θ _2H . Thus, it can be seem that the portion of the horizontal deflection winding in quadrant I comprises a step function of two steps of conductors extending through angles θ ₁ and θ ₂ . That portion of the quadrant in which the two steps i.e., θ ₁ and θ ₂ overlap, results in a higher conductor density than that portion where only the conductors from the θ ₁ step are present. Referring generally to FIG. 4, it can be seen that the horizontal winding portions are symmetrically in each quadrant about the horizontal axis 26.

Referring to quadrant II of FIG. 4 the distribution of a portion of the vertical deflection winding is illustrated. This distribution comprises a first number of conductors spaced-apart 2° and extending through an angle θ _IV starting from the vertical axis 27, and a second number of conductors spaced-apart 2° and extending through an angle θ _2V starting from the vertical axis 27. It can be seen that in the portion of the quadrant where the two angles θ _1V and θ _2V overlap that the conductors density is greater than in that portion of the quadrant containing only the wires of the θ _1V function. Referring generally to FIG. 4, it can be seen that the vertical deflection winding comprises symmetrical portions in each of the quadrants about tee vertical axis 27.

Referring to quadrant II of FIG. 4, wires 21c and 21d are shown on the outside perimeter of core 22. Wires 21c are the return wires for the active conductors 21a and 21d are the return wires for the active conductors 21b. It is to be understood that these return wires extend around the entire perimeter of core 22.

FIG. 5 illustrates the wire distribution at the front end of the yoke. As can be seen clearly in FIGS. 1 and 2, the yoke 20, mounted adjacent the flared bulb section of the picture tube has a front end portion which has a greater diameter than the rear end portion. Therefore, with the same angular spacing between the conductors at the rear end and front end portions of the yoke, it can be seen that the conductors will have a greater linear spacing around the perimeter at the front of the yoke than at the rear of the yoke. For this reason, the conductors at the front of the yoke do not form one layer on top of another but rather, as shown in FIG. 5, form a single-layer comprising alternate conductors 21a and 21b. The spacing between the conductors 21a is 2° and the spacing between the conductors 21b is 2°, the same angular spacing exits at the rear of the yoke. Wires 21c at the outside perimeter of core 22 are the return wires for active conductors 21a and wires 21d are the return wires for active conductors 21b. It is to be understood that the conductors shown in FIG. 5 extend around the perimeter of core 22.

The individual conductors indicated by capital letters in the four quadrants of FIG. 4 represent the start and finish of the various horizontal and vertical winding portions in each of the quadrants.

FIG. 6 is a schematic representation of the horizontal and vertical coil windings formed by the portions of these windings in the four quadrants of FIG. 4. The letters of FIG. 6 indicate which portions of the horizontal and vertical windings of FIG. 4 are electrically interconnected to form the complete horizontal and vertical windings.

One example of a yoke constructed according to the invention and used successfully with an RCA-type 15NP22, 15 inches diagonal, 90° delta gun shadow mask color picture tube is as follows, referring to FIG. 4 for orientation:

Wire used: No. 23 copper, wound on a flared ferrite core having a 2.2 inches length, 1.68 inches small end inside diameter and 4.0 inches inch large end inside diameter, the core having a thickness of 0.3 inch.

θ _1H , 70° (35 convolutions)

θ _2H , 7° (4 convolutions)

θ _1V , 77° (39 convolutions)

θ _2V , 18° (9 convolutions)

Although the specific embodiment described utilized only two parameters, i.e., θ ₁ and θ ₂ for each portion of the horizontal and vertical deflection coil windings, is to be understood that three of more parameters corresponding to three or more stairsteps may be used as required to permit the necessary freedom of design in determining the conductor distribution of any particular yoke.

Also, as illustrated in the described embodiment, only two initial layers of wires were wound toroidally around the core. It will be appreciated that even though only two parameters were selected for determining the distribution of conductors, these two parameters (θ ₁ and θ ₂ ) may extend over such relatively large angles in each quadrant that the individual conductors might overlap in three layers. This would be of little consequence as in actual practice the wires are so small in diameter in relation to the front and rear diameters of the yoke that the overlapping layers do not adversely affect yoke performance.

As previously mentioned the problems of maintaining good beam registration and convergence in delta gun color television systems increase as tubes employing larger beam deflection angles and viewing areas are utilized. As a practical matter it is desirable to limit the toroidal deflection yoke windings to no more than two layers of conductors as it becomes more difficult to lay down a third layer and maintain the proper relationship of the conductors in each layer one to the other. It has been found that a two layer yoke embodying the invention may be utilized in conjunction with wide angle large screen color picture tubes such as a tube having a beam deflection angle of 100° by building the yoke with an additional design parameter. This additional design parameter to be described subsequently permits a two layer toroidal yoke to be satisfactorily utilized with large screen, wide deflection angle picture tubes.

The additional parameter which gives greater design freedom for minimizing beam landing aberrations comprises one or more conductors of one of the coils disposed in such a location in each quadrant of the yoke that convergence and registration can be maintained throughout the raster while maintaining minimum coma in the horizontal coil. These additional conductors may be considered as providing a relatively small perturbation of the two layer winding described in the first-described embodiment. It is necessary that these additional wires be accurately located such that they do not degrade one performance characteristic provided by the yoke, in particular, coma in the horizontal coils, while improving other performance characteristics, such as corner convergence and registration. The angle about which the conductors must be placed to accomplish this may be called the coma invariant angle of the horizontal coils. FIG. 7 illustrates a winding distribution of conductors at the rear of a toroidally wound deflection yoke including the additional winding parameter discussed above. The coils may be wound on the yoke in a conventional manner by winding two layers of conductors around the yoke and then appropriately peeling and interconnecting conductors as shown in FIGS. 7 and 8.

Included in the two layers of conductors are conductors 34 representative of the conductors of the horizontal coil and conductors 35 representative of the conductors of the vertical coil. A portion of the return horizontal conductors 34a and return vertical conductors 35a are shown on the outside of ferrite core 31 in quadrant II. The quadrants I, II, III and IV of the yoke are symmetrical about the orthogonal X (horizontal) axis 32 and Y (vertical) axis 33. The angles shown in quadrant I represent the conductor distribution for the horizontal coil in one quadrant; this distribution is the same in all of the quadrants. The angles in quadrant II refer to the winding distribution of the conductors comprising the vertical coil in one quadrant. This distribution is the same in all of the quadrants.

Referring to quadrant I of FIG. 7, the first layer of conductors includes a portion of horizontal conductors 34 having a predetermined angular separation from each other extending throughout an angle θ _1H from the X-axis 32. In the second layer similar conductors 34 extend over an angle θ _2H from the X-axis 32. Additionally, further horizontal conductors 34 extend throughout an angle θ _3H -θ _4H measured from the X-axis 32. These additional horizontal turns comprise the perturbation of the horizontal winding for providing optimum registration and convergence while maintaining coma at a minimum. These additional conductors, five in the illustrated embodiment, are centered about a conductor 34c which is disposed at the above-described coma invariant angle. It should be noted that these additional conductors are disposed in a separation of the vertical conductors in the second winding layer.

In quadrant number II vertical conductors 35 having a predetermined angular separation extend over an angle θ _2V in the first layer measured from the Y-axis 33. Further, vertical conductors 35 in the second layer extend over an angle θ _1V measured from the Y-axis 33. A separation is provided in the vertical conductors extending over an angle θ _4V -θ _1V measured from the Y-axis 33. Additional vertical conductors in the second layer extend over an angle θ _3V -θ _4V measured from the Y-axis 33. It should be noted that the horizontal conductors 34 centered about the coma invariant angle are disposed in the second layer within the separation of the vertical conductors 35.

FIG. 8 illustrates schematically the interconnection of the vertical and horizontal coil portions contained within the first and second layers shown in FIG. 7 for forming the desired vertical and horizontal deflection coils of the yoke. The capital letters in FIG. 8 are referenced to capital letters indicating the end conductors of portions of the respective horizontal and vertical coil portions shown in FIG. 7.

The following discussion relates to the coma invariant angle mentioned above. Horizontal coil coma aberrations, or inappropriate width of the blue raster as the picture tube electron beam is scanned over the inside of the viewing screen along the horizontal center line, is related to the yoke parameters by equation (2) above, in which (f) corresponds to the blue width aberration.

By transforming the independent set of step angle variables (θ _1H , θ _2H , θ _1V , θ _2V ) to its unique counterpart set of moment angle variables (M _1H , M _2H , M _1V , M _2V ) (to be explained subsequently) and then by applying the aforementioned recursion scheme to optimize over the set of moment angle variables, a relation analogous to equation 2 is obtained for any of the multitude of aberrations to be minimized.

(3) W= aM _1H + bM _2H = cM _1V + dM _2V + e

in which W is the blue width aberration, M ₁ and M ₂ are the first and second moments of the cross section of the deflection yoke conductor distribution, and a, b, c, d and e are the constants obtained from the above described recursion scheme.

The first moment (M ₁ ) in each quadrant may be considered the center of gravity of a transverse cross section of the coil conductors and is expressed by the following equation:

in which n is the total number of wires per quadrant of the horizontal coil under consideration and θ _i is the angle location of the i ^th wire as measured from the horizontal axis of symmetry.

The second moment (M ₂ ) in each quadrant may be considered the spread of conductors about the first moment given in (4) above and is expressed by the equation:

Finally, the coma invariant angle (θ _c ) may be derived from equations (3), (4) and (5) and is expressed by the equation:

in which values for M _1H , M _2H and (a) and (b) are obtained from the recursion scheme results.

It should be noted that the blue width aberrations or coma are measured with no vertical deflection current present in the yoke so that (c) and (d) terms of equation (3) are zero. Thus, the optimization scheme described in conjunction with the embodiment shown in FIG. 4 yields a yoke which may then be utilized further in the embodiment described in conjunction with FIG. 7.

Once the coma invariant angle is determined for a particular coil in a yoke there is some freedom in the amount of conductors to be added around this point. The exact number can be determined empirically by observing the performance of the yoke as the wire is added. As long as the number of added conductors is small relative to the total number of conductors the coma will not be adversely affected. It should be noted that in the described embodiment it was necessary to separate the vertical turns in order to accommodate the additional horizontal turns. Referring to FIG. 7, it can be seen that the vertical conductors are separated in the area of least concentration of vertical conductors. With this arrangement the coil parameters can be readily optimized to their final values by use of the optimization scheme described in conjunction with FIG. 4.

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ITT Corporation (NYSE: ITT) is a global diversified manufacturing company with 2008 revenues of $11.7 billion. ITT participates in global markets including water and fluids management, defense and security, and motion and flow control. Forbes.com named ITT Corporation to its list of "America's Best Managed Companies" for 2008, and awarded the company the top spot in the conglomerates category.

ITT's water business is the world's largest supplier of pumps and systems to transport, treat and control water, and other fluids. The company's defense electronics and services business is one of the ten largest US defense contractors providing defense and security systems, advanced technologies and operational services for military and civilian customers. ITT's motion and flow control business manufactures specialty components for aerospace, transportation and industrial markets.

In 2008, ITT was named to the Dow Jones Sustainability World Index (DJSI World) for the tenth time in recognition of the company's economic, environmental and social performance. ITT is one of the few companies to be included on the list every year since its inception in 1999.

The company was founded in 1920 as International Telephone & Telegraph. During the 1960s and 1970s, under the leadership of its CEO Harold Geneen the company rose to prominence as the archetypal conglomerate, deriving its growth from hundreds of acquisitions in diversified industries. ITT divested its telecommunications assets in 1986, and in 1995 spun off its non-manufacturing divisions, later to be purchased by Starwood Hotels & Resorts Worldwide.

In 1996, the company became ITT Industries, Inc., but changed its name back to ITT Corporation in 2006.



History

ITT was formed in 1920, created from the Puerto Rico Telephone Company co-founded by Sosthenes Behn.[1] Its first major expansion was in 1923 when it consolidated the Spanish Telecoms market into what is now Telefónica.[2] From 1922 to 1925 it purchased a number of European telephone companies. In 1925 it purchased the Bell Telephone Manufacturing Company of Brussels, Belgium, which was formerly affiliated with AT&T, and manufactured rotary system switching equipment. In the 1930s, ITT grew through purchasing German electronic companies Standard Elektrizitaetsgesellschaft (SEG) and Mix & Genest, both of which were internationally active companies. Its only serious rival was the Theodore Gary & Company conglomerate, which operated a subsidiary, Associated Telephone and Telegraph, with manufacturing plants in Europe.

In the United States, ITT acquired the various companies of the Mackay Companies in 1928 through a specially organized subsidiary corporation, Postal Telegraph & Cable. These companies included the Commercial Cable Company, the Commercial Pacific Cable Company, Postal Telegraph, and the Federal Telegraph Company.





International telecommunications

International telecommunications manufacturing subsidiaries included STC in Australia and Britain, SEL in Germany, BTM in Belgium, and CGCT and LMT in France. Alec Reeves invented Pulse-code modulation (PCM), upon which future digital voice communication was based. These companies manufactured equipment according to ITT designs including the (1960s) Pentaconta crossbar switch and (1970s) Metaconta D, L and 10c Stored Program Control exchanges, mostly for sale to their respective national telephone administrations. This equipment was also produced under license in Poznań (Poland), and in Yugoslavia, and elsewhere. ITT was the largest owner of the LM Ericsson company in Sweden but sold out in 1960.




1989 breakup

In 1989 ITT sold its international telecommunications product businesses to Alcatel, now Alcatel-Lucent. ITT Kellogg was also part of the 1989 sale to Alcatel. The company was then sold to private investors in the U.S. and went by the name Cortelco Kellogg. Today the company is known as Cortelco (Corinth Telecommunications Corporation, named for Corinth, MS headquarters). ITT Educational Services, Inc. (ESI) was spun off through an IPO in 1994, with ITT as an 83% shareholder. ITT merged its long distance division with Metromedia Long Distance, creating Metromedia-ITT. Metromedia-ITT would eventually be acquired by Long Distance Discount Services, Inc. (LDDS) in 1993. LDDS would later change its name to Worldcom in 1995.

In 1995, ITT Corporation split into 3 separate public companies:

* ITT Corp. — In 1997, ITT Corp. completed a merger with Starwood Hotels & Resorts Worldwide, selling off its non-hotel and resorts business. By 1999, ITT completely divested from ITT/ESI; however, the schools still operate as ITT Technical Institute using the ITT name under license.[1] Also in 1999, ITT Corp. dropped the ITT name in favor of Starwood.[7]
* ITT Hartford (insurance) — Today ITT Hartford is still a major insurance company although it has dropped the ITT from its name altogether. The company is now known as The Hartford Financial Services Group, Inc.
* ITT Industries — ITT operated under this name until 2006 and is a major manufacturing and defense contractor business.
o On July 1, 2006, ITT Industries changed its name to ITT Corporation as a result of its shareholders vote on May 9, 2006.




Purchase of International Motion Control (IMC)

An agreement was reached on June 26, 2007 for ITT to acquire privately held International Motion Control (IMC) for $395 million. The deal was closed and finalized in September 2007. An announcement was made September 14, 2010, to close the Cleveland site.
Purchase of EDO

An agreement was reached September 18, 2007 for ITT to buy EDO Corporation for $1.7 billion.[12] After EDO shareholders' approval, the deal was closed and finalized on December 20, 2007.


Purchase of Laing

On April 16, 2009, ITT announced it has signed a definitive agreement to acquire Laing GmbH of Germany, a privately held leading producer of energy-efficient circulator pumps primarily used in residential and commercial plumbing and heating, ventilating and air conditioning (HVAC) systems.


2011 breakup

On January 12, 2011, ITT announced a transformation to separate the company into 3, stand-alone, publicly-traded, and independent companies.

The International Telephone and Telegraph Company was founded in 1920 by Colonel Sosthenes Behn. Early takeovers formed the company into a worldwide leading conglomerate for telephone technology and other communication technologies - a role that was further supported by the company's expansion during World War II.

After the war ITT expanded in other trades such as automobile technology, satellite communication, liquid technologies, and even the hotel business with the takeover of Sheraton Hotels in the year 1968.

In 1979 the company started to sell off some of its wide spread fields of action. A process that reached its peak in 1995 with the split into three separate listed companies - ITT Industries, ITT Hartford Group and ITT Destinations. ITT Destinations, a service provider in the hospitality industry was later sold to Starwood Hotels & Resorts. The ITT Hartford Group, a subsidiary in the insurance industry was separated as Hartford Financial Services.

Today ITT Corp. is a worldwide operating enterprise with a turnover of 9 bln US$ in the year 2007 and leading positions in its four main areas of operations. Around 40.000 people are employed worldwide. The company is seated in White Plains, New York.

ITT is the worldwide leading supplier of pumps, systems, and services for the control and treatment of water and other liquids. The company is a main supplier of high-end military defense systems and offers its technical and operational services to a wide range of government agencies. Further, ITT produces plugs, switches, and wirings which are being used in telecommunications, computers, aviation, industrial applications, and networks. ITT is also a manufacturer of industrial components which are being used in transportation, construction, and aviation.

ITT's history in consumer electronics reaches back far into the year 1930 when ITT became a major shareholder in the company "Mix & Genest AG" which was founded in 1879 by Wilhelm Mix and Werner Gerest, as well as the company "C. Lorenz AG" which was founded in 1880 by Carl Lorenz. These two companies had their main fields of business in radio technology, whereas the "C. Lorenz AG" positioned itself with the takeover of the "G. Schaub Apparatebau-Gesellschaft mbH" in 1940 in the development and manufacturing of radio broadcast receivers. From 1950 on all products were manufactured by Schaub in the city of Pforzheim; in 1952 the model range of both companies was merged and the distribution of Lorenz radios was integrated in the company Schaub. From 1955 on all products were distributed under the brand name "Schaub-Lorenz". In 1958 the companies "Standard Elektrik AG" and "C. Lorenz AG" were merged into the "Standard Elektrik Lorenz AG" (SEL). From 1979 on this field of business was named "Audio-Video-Elektronik" and belonged to ITT; the products - such as television sets, radios, car radios, cassette recorders, world receivers, and speaker boxes - were being distributed under the brand name "ITT Schaub-Lorenz". In 1987 ITT established together with the French "Companie Générale d'Électricité" the European group of companies named "Alcatel n.v.", where the consumer electronics branch was sold to Nokia in early 1988. With that, Schaub-Lorenz, as well as the TV manufacturer Graetz, which was taken over by SEL in 1961, belonged to Nokia. From then on Nokia distributed consumer electronics products, such as television sets, video recorders, and amplifiers under the brand name "ITT Nokia". Nokia, however, soon quit the distribution of consumer electronics and focused on the manufacturing of mobile phones...

HISTORY OF Standard Elektrik Lorenz AG IN GERMAN:

Die Standard Elektrik Lorenz AG (heute Alcatel-Lucent Deutschland AG) ist ein Unternehmen der Nachrichtentechnik (früherer Slogan: SEL – Die ganze Nachrichtentechnik) mit Hauptsitz in Stuttgart. Zur Nachrichtentechnik zählen auch Informations- und Kommunikationstechnik, Telekommunikationstechnik (SEL war für die Röchelschaltung bekannt) und früher Fernmeldetechnik oder Schwachstromtechnik. Einen weiteren Geschäftsbereich hatte das Unternehmen in der Bahnsicherungstechnik, so wurden für die Deutsche Bundesbahn Relaisstellwerke und elektronische Stellwerke mit den dazugehörigen Außenanlagen (Signale, Gleisfreimeldeanlagen, Weichenantriebe) sowie die Linienzugbeeinflussung entwickelt und gebaut, welche auch bei ausländischen Bahnen Abnehmer fanden. Der Bereich gehört seit 2007 als Thales Transportation Systems GmbH (seit 02.2011 vorher Thales Rail Signalling Solutions GmbH) zum Thales-Konzern. Die bereits 1998 ausgegliederten Bereiche Alcatel Air Navigation Systems und SEL Verteidigungssysteme sind ebenfalls heute in Thales Deutschland beheimatet.[1]
Fernseher Illustraphon 743 von 1957
„Goldsuper Stereo 20“ (1961)
Das Flaggschiff der erfolgreichen Schaub-Lorenz Kofferradios der sechziger Jahre: Touring 70 Universal
Erster Digitalfernseher der Welt (1983)

Bis 1987 gehörte SEL zusammen mit anderen auf dem Sektor Telekommunikation in anderen Ländern tätigen Schwesterfirmen zum US-amerikanischen Mischkonzern International Telephone and Telegraph (ITT). ITT verkaufte die Aktien-Mehrheit an den ITT-Telekommunikationsfirmen an die französische Compagnie Générale d’Electricité (CGE), die nach der Zusammenfassung mit den eigenen Telekommunikationsaktivitäten daraus die Alcatel N.V. bildete.

Die Standard Elektrik Lorenz AG wurde 1993 in Alcatel SEL AG umbenannt. Die Aktienmehrheit liegt mit über 99 % bei der Alcatel. Mit der Fusion von Alcatel und Lucent zu Alcatel-Lucent am 1. Dezember 2006 und der Neu-Firmierung beider Unternehmen in Deutschland zur Alcatel-Lucent Deutschland AG entfiel der Zusatz SEL.


Geschichte

Die beiden Stammfirmen des Unternehmens, die Mix & Genest AG und die Telegraphenbauanstalt von C. Lorenz, wurden 1879 bzw. 1880 gegründet. Das erste Patent von Mix & Genest datiert von 1883, das erste Patent von C. Lorenz ist aus dem Jahr 1902.

Das Unternehmen Mix & Genest war wesentlicher Teil der Standard Elektrizitäts-Gesellschaft (SEG), in die auch die Süddeutsche Apparatefabrik (SAF), die 1875 von F. Heller als "Friedrich Heller, Fabrik Elektrotechnischer Apparate" gegründet wurde, integriert wurde. Der technische Schwerpunkt von Mix & Genest bzw. SEG sowie der C. Lorenz AG war der klassischen Fernmelde- bzw. Funktechnik zuzuordnen. Die C. Lorenz AG baute in den 1920er und 1930er Jahren Großsender für den neu gegründeten Rundfunk.

1930 übernahm die International Telephone and Telegraph Company (ITT) die Aktienmehrheit der Mix & Genest AG und der C. Lorenz AG. [2]

Die C. Lorenz AG positionierte sich mit der Übernahme der G. Schaub Apparatebau-Gesellschaft mbH im Jahr 1940 in der Entwicklung und Herstellung von Rundfunkempfängern. Ab dem Jahr 1950 wurden alle Geräte bei Schaub in Pforzheim gefertigt. 1952 wurde das Typenprogramm beider Unternehmen verschmolzen und der Lorenz-Radio-Vertrieb in die Firma Schaub integriert. Ab 1955 wurden die Geräte unter dem Namen Schaub-Lorenz vertrieben.

1956 wurde das Unternehmen SEG in Standard Elektrik AG umbenannt. Ebenfalls 1956 wurde ein Kabelwerk gegründet. Wesentlicher Motor für das 1957 gegründete Informatikwerk war Karl Steinbuch, der von 1948–1958 dem Unternehmen, zuletzt als Technischer Direktor und Leiter der Zentralen Forschung, angehörte.

1958 erfolgte die Vereinigung der Standard Elektrik AG mit der C. Lorenz AG zur Standard Elektrik Lorenz AG (SEL).

Die Standard Elektrik Lorenz AG übernahm 1961 die Graetz KG. Die Firmenteile Schaub-Lorenz und Graetz waren zusammen mit einem Bildröhrenwerk Bestandteil der Unternehmensgruppe Audio Video der SEL AG, die 1979 als Audio-Video-Elektronik in die ITT ausgegliedert wurde. Die Produkte, die unter anderem Fernsehgeräte, Radios, Autoradios, Kassettenrecorder, Weltempfänger und Lautsprecherboxen umfassen, wurden fortan unter dem Namen ITT Schaub-Lorenz vertrieben.[2]

Versuche, auf dem neuen Gebiet der Raumfahrt-Elektronik Fuß zu fassen, waren auf folgende Produkte beschränkt:

* AZUR: Telemetrie/Telekommandogeräte
* Spacelab: Datenerfassung/Kommandoterminal.

SEL entwickelte zu Beginn der 1970er Jahre das Präzisionsanflugverfahren SETAC. Dieser Unternehmensbereich wurde im Jahre 1987 von der finnischen Firma Nokia übernommen.

1976 hatte SEL ein Grundkapital von 357 Mio. DM bei 33.000 Beschäftigten und einem Umsatz von 2,6 Mrd. DM.

1983 stellte SEL auf der Internationalen Funkausstellung Berlin 1983 mit dem ITT Digivision den weltweit ersten Fernseher mit digitaler Signalverarbeitung vor.

2003 wurden die Markenrechte am Namen Schaub Lorenz an die italienische General Trading SpA verkauft. Die neugegründete Schaub Lorenz International GmbH vertreibt seitdem unter dem alten Markennamen Schaub-Lorenz importierte Konsumelektronik aus dem unteren Preisbereich.