US2980815A - Deflection yoke assembly for cathode ray tubes - Google Patents

Description

April 8, 9 1 M. E. ECKER 2,980,815

DEFLECTION YOKE ASSEMBLY FOR CATHODE RAY TUBES Filed Aug. 5. 1957 f3 1a 7/044 mar/e41. ,7 DEF'Zs'cr/a/V 05/450770 If ATTORNEY DEFLECTION YOKE ASSEMBLY FOR CATHODE RAY TUBES Mario E. Ecker, Pennsauken, NJ., assignor to Radio Corporation of America, a corporation of Delaware Filed Aug. 5, 1957, Ser. No. 676,121

11 Claims. (Cl. 313-76) This invention relates to a deflection yoke assembly for cathode ray tubes, and more particularly to a deflection yoke assembly including printed circuitry and associated supporting structure.

In presently used deflection yoke assemblies for television picture tubes, portions of the circuits for the deflection coils are supported on an annular disc of insulating material fixed to one end of the assembly. Since the circuit for the horizontal deflection coils is a high voltage circuit and the circuit for the vertical deflection coils is a low voltage circuit, the various components and conductors must be very strategically placed with respect to the voltages involved. This necessitates the use of a relatively large supporting disc which increases the overall diameter of the deflection yoke assembly. This is a disadvantage in view of the present trend towards smaller and smaller chassis wherein available space becomes more and more important.

The annular supporting disc may be fabricated from phenolic sheets or other suitable sheet material. In view of the configuration of the disc, even though it may be fabricated in the form of two segments, there is considerable wastage of the sheet material in fabrication.

An object of this invention is to provide a novel deflection yoke assembly including printed circuit elements to facilitate mechanization in fabricating the assembly.

Another object of this invention is to provide a deflection yoke assembly including novel means for supporting printed circuit strips which comprise portions of the associated circuits.

A further object of this invention is to provide a deflection yoke assembly which is compact in size, and which is adapted for mechanization in manufacture.

An assembly, in which the above objects are realized, comprises two pairs of deflecting coils disposed in interlocking realtionship and having linear coil sides arranged to extend lengthwise along the surface of the neck portion of a cathode ray tube. A segmental ring of magnetic material encloses the coil sides, which define a hollow cylinder. The above elements are held together by a hinged ring clamp which includes two parallel grooves extending substantially completely around its outer periphery. A printed circuit strip is disposed in each of the grooves, the strips being separated by a rib barrier between the grooves. A strip cover for the ring closes the grooves and encloses circuit strips disposed therein.

One advantage of the above described structure is that it permits the use of simple printed circuits which are readily adapted to be assembled and soldered by automatic or semi-automatic machines. Another advantage of the structure is that portions of the deflecting circuit may be mounted extremely close to the deflection coils, yet suitable electrical separation is provided between the high and low voltage portions of the circuit. Still another advantage of the structure is that the assembly of the coils and associated circuits with the remainder of the yoke assembly is facilitated. A further advantage of the structure is that it permits a reduction in the overall States Patent-O A Patented Apr. 18, 1961 2 diameter of a substantial portion of the deflection yoke assembly. Size reduction is particularly important in view of a trend toward a chassis which is.mounted in a plane perpendicular to the neck of the tube. In this type of chassis, the neck and the deflection yoke protrude through a hole in the chassis. It is desirable that the hole be as small as possible.

The novel features of the invention as well as additional objects and advantages thereof, will be understood more fully from the following description when read in connection with the accompanying drawing, in which:

Figure 1 is a side view of a portion of a cathode ray tube illustrating, partially in section, a deflection yoke assembly;

Figure 2 is a detail view, partially broken away, of the ring clamp, appearing in Figure 1, for holding the deflection yoke assembly together and for supporting the printed circuit strips; and

Figure 3 is a view of one printed circuit strip, also appearing in Figure 1, and associated circuit components, which are schematically shown.

Referring now in detail to the accompanying drawings, Figure 1 illustrates a preferred deflection yoke assembly mounted on a cathode ray tube 11. A pair of vertical deflection coils 13 and a pair of horizontal deflection coils 15 are mounted on a supporting form 17, made of a plastic insulating material. The two pairs of deflecting coils are arranged to deflect the cathode ray, when energized, in two mutually perpendicular transverse planes through the axis of the tube 11. The resultant field vector direction and strength determines the terminal trace of the ray upon the tube screen. The coils are saddleshaped having thin straight sides interlocked so as to form a substantially complete, thin-walled, hollow cylinder and have outwardly-bent curved ends. The horizontal deflection coils 15 are shown as the top and bottom coils in Figure 1. The vertical deflection coils 13 are shown as the side coils in Figure 1.

The form 17 may be made in two sections for ease of fabrication. The form comprises a substantially cylindrical center portion 19, a large flared end portion 21, and a flanged end portion 23. The center portion 19 is dimensioned slightly larger than the neck of the cathode ray tube 11. The flared end portion 21 of the form is shown at the left in Figure 1 and lies adjacent to the flared surface of the cathode ray tube 11. In assembling the deflection coils with the form 17, the horizontal deflection coils 15 are mounted internally of the form, the end portions of the coils lying contiguous to the end portions of the form. The sides of the horizontal deflection coils are covered by the central portion 19 of the form 17. The vertical deflection coils 13 are mounted externally of the form 17, the end portions of the horizontal coils also lying contiguous to the end portions'of the form. The central portion 19 of the form is provided with openings to permit the sides of the horizontal coils to lie contiguous to the neck of the cathode ray tube. Hence, all of the coil sides lie very close to the neck of the tube 11.

In'order to complete the magnetic circuits for the de-" fleeting coils, a cylindrical core 25, of term-magnetic material, is placed around the outside surface of the cylinder defined by the assembled deflection coils. The core 25 may be constructed in the form of either two or four segments for the purpose ofassembly. The core may lie in direct contact with the vertical deflection coils 13,

In order to hold the above-described assembly together, a ring clamp 27 is fitted around the external surface of the core 25. The clamp 27, shown in detail in Figure2, is made from a plastic or other suitable insulating material. The clamp is comprised of'two segments, each of Whichhas a radial clamping flange 29 at one end; The flanges 29 are provided with apertures adapted to receive a nut and bolt, for example. The other ends of the clamp segments are provided with mating coupling portions 31 and 33 so that the two segments may be joined to form, in effect, a continuous ring. The clamp is provided with two parallel grooves 35 lying in its outer surface and extending substantially from a point adjacent one flange 29 to a point adjacent the other flange 29. The grooves are separated by a rib 37 which acts as an electrical barrier between the two grooves. A mounting post 39 is provided adjacent to each end of each groove for the purpose of supporting and for securing a printed circuit strip 41 within each of the grooves 35.

One of the printed circuit strips 41 is shown in detail in Figure 3. Each printed circuit consists of a strip of flexible, insulating material having printed conductors 43 formed integrally with one surface thereof. The strips 41 may be fabricated in accordance with any of the wellknown techniques. A hole 45 is provided adjacent to each end of the strips for the purpose of securing the strip over the mounting posts 39. The circuit illustrated in Figure 3 includes two resistors 47 and one pair of deflection coils 13. One coil 13 is connected across each of the resistors 47 and connected to the printed circuit strip by means of leads 49. Leads 51, which are secured adjacent to each end of the circuit strip 41, are provided for connecting the printed circuitry to other portions of the deflection circuitry. The grooves 35 of the clamp 27 are deep enough so that when the printed circuit strips 41, with components attached, are mounted on the clamp, they are completely received within the grooves. The rib 37 provides a leakage barrier between the two circuit strips.

A cover 53, in the form of a strip of insulating material, is secured over the outside of the clamp 27 and closes the grooves 35. The cover 53 may be in the form of'a simple strip, having holes adapted to receive screws 55 for securing the cover to the clamp, or it may be in the form of a resilient material adapted to be snapped into the grooves and to be self-held. Means areprovided either in the cover strips or in the ring clamp to permit the necessary leads to pass out of the closed grooves.

What is claimed is: 1. A deflection yoke assembly adapted to be closely fitted around the neck portion of a cathode ray tube, said assembly comprising transverse deflecting coils, each coil having thin linear coil sides arranged to extend lengthwise along the surface of said neck portion of a cathode ray tube, means for supporting and positioning said deflecting coils whereby said coil sides define a hollow cylinder, a ring core of magnetic material enclosing said coil sides, a clamping ring of insulating material for holding said coil and core assembly together, said ring having at least one groove extending partially around its outer surface, a flexible printed circuit strip carrying circuitry for said coils disposed in said groove, and means for securing said strip in said groove, said groove being sufliciently deep to accommodate said printed circuit strip with, components mounted thereon.

2. A deflection yoke assembly adapted to be closely fitted around the neck portion of a cathode ray tube, said assembly comprising transverse deflecting coils, each coil having a pair of thin linear coil sides arranged to extend lengthwise along the surface of the neck portion of a cathode ray tube, a form of insulating plastic material for supporting said deflecting coils, said coil sides being supported to define a hollow cylinder, a segmental ring core of magnetic material enclosing said coil sides, a clamping ring of insulating material for holding said core and coil assembly together, said ring comprisingmating half portions each having a complementary clamping means at one end, said ring having at least one groove extending partially around its outer surface, a pair of mounting posts disposed at spaced points in said groove, a flexible printed circuit strip disposed in said groove, said strip having holes adjacent to the ends thereof for engagement with said mounting posts, said groove being sufliciently deep to accommodate said mounting posts and said printed circuit'strips with components mounted thereon, and a cover closing said ring groove and the printed circuit strip disposed therein.

3. A deflection yoke assembly adapted to be closely fitted around the neck portion of a cathode ray tube, said assembly comprising two pairs of transverse deflecting coils, each coil having a pair of thin linear coil sides arranged to extend lengthwise along the surface of said neck portion, said coil sides each subtending substantially of arc and being interlocked to form a substantially complete hollow cylinder, a form of insulating plastic material for supporting said deflecting coils, a segmental ring core of magnetic material enclosing said coil sides of said interlocked coils, a clamping ring of insulating material for holding said assembly together, said ring comprising mating half .portions each having a complementary clamping means at one end, said ring having two grooves extending partially around its outer surface, a pair of mounting posts disposed at spaced points in each of said grooves, a flexible printed circuit strip disposed in each of said grooves, each strip having holes adjacent to the ends thereof adapted to be engaged with said mounting posts, said grooves being sufficiently deep to accommodate said mounting posts and said printed circuit strips with components mounted thereon, said grooves being separated by a ridge defining a leakage barrier, and a cover closing said ring grooves and the printed circuit st-rips disposed therein.

4. In a deflection yoke assembly adapted to be fitted around the neck portion of a cathode ray tube, said as.- sembly including deflection coils having thin, linear coil sides arranged to extend lengthwise along the surface of said neck portion and a segmental ring of magnetic material enclosing said coil sides, a ring of insulating material for holding said assembly together, said ring having ends separated from each other, said ring including clamping means for joining said separated ends thereof, said ring having at least one groove extending around the outer periphery thereof, a flexible printed circuit strip disposed in said groove, and means for holding said strip in said groove, said strips comprising circuitry for said deflection coils.

5. In a deflection yoke assembly adapted to be fitted around the neck portion of a cathode ray tube, said assembly including deflection coils having thin linear coil sides arranged to extend lengthwise along the surface of said neck portion and a segmental ring of magnetic ma terial enclosing said coil sides, a ring of insulating material for holding said assembly together, said ring having ends separated from each other, said ring including clamping means for joining said separated ends thereof, said ring having a pair of grooves extending around the outer periphery thereof, said grooves being separated by a rib to provide a leakage barrier, a flexible printed circuit strip disposed in each of said grooves, means for securing said strips in said grooves, said strips comprising circuitry for said deflection coils, and a cover secured to said ring for enclosing said grooves and the printed circuit strips disposed therein.

6. In a, deflection yoke assembly including deflection coils positionable around the neck of a cathode ray tube and circuit means connectable to said coils, clamping means of insulating material around said coils for holding-said coils in position around said tube neck comprising an annular member of insulating material having a groove in its outer periphery for receiving said circuit means within said groove.

7. In a deflection yoke assembly adapted to be fitted around the neck portion of a cathode ray tube, said assembly including deflection coils arranged to extend lengthwise along the surface of said neck portion, a core of magnetic material around said coils, and circuitry connected to said coils, the improvement which comprises a ring of insulating material for holding said assembly together, clamping means for fastening said ring on said neck portion, said ring having at least one groove extending around the outer periphery thereof, and a printed circuit strip carrying said circuitry and disposed in said groove.

8. In a deflection yoke assembly adapted to be fitted around the neck portion of a cathode ray tube, said assembly including a horizontal deflection coil and a vertical deflection coil both arranged to extend lengthwise along the surface of said neck portion, a core of magnetic material around the sides of said coils, circuitry connected to said horizontal deflection coil, and different circuitry connected to said vertical deflection coil, the improvement which comprises a ring of insulating material for holding said assembly together, said ring having ends separated from each other, said ring ineluding clamping means for joining said separated ends thereof, said ring having a pair of adjoining grooves extending around the outer periphery thereof, a printed circuit strip carrying said circuitry for said horizontal deflection coil and disposed in one of said pair of grooves, and another printed circuit strip carrying said circuitry for said vertical deflection coil and disposed in the other of said pair of grooves.

9. In a deflection yoke assembly including deflection coils adapted to be positioned around the neck of a cathode ray tube and a member of insulating material for holding said coils around said tube neck, circuit means for said coils comprising at least one strip of insulating material having opposite surfaces, circuits printed on one of said surfaces, means for mounting said strip around said member with one of said surfaces against the face of said holding member, and means associated with said circuit means and said member for providing insulation between said circuit means and said deflection coils.

10. In a deflection yoke assembly including coils adapted to be positioned around the neck of a cathode ray tube and an annular member of insulating material for holding said coils on said tube neck, circuit means for said coils comprising an elongated member of flexible insulating material, a circuit printed on said strip, means for mounting said elongated member around said holding member whereby said printed circuit conforms to the annular shape of said holding member, and means associated with said circuit means and said annular member for providing insulation between said circuit means and said deflection coils.

11. In a deflection yoke assembly including a horizontal deflection coil and a vertical deflection coil adapted to be positioned around the neck of a cathode ray tube and a holding member of insulating material for holding said coils around said tube neck, circuit means for said coils comprising a first printed circuit, a second printed circuit, means disposed between said first printed circuit and said second printed circuit for providing insulation between said first and second printed circuits, at least one flexible member of insulating material on which said printed circuits are arranged, means for mounting said member of insulating material around said holding 7 member, means for connecting said first printed circuit to said horizontal deflection coil, means for connecting said second printed circuit to said vertical deflection coil, and means associated with said printed circuits and said flexible member for providing insulation between said printed circuits and said deflection coils.

References Cited in the file of this patent UNITED STATES PATENTS 2,228,821 Hansen Jan. 14, 1941 2,428,947 Torsch Oct. 14, 1947 2,611,040 Brunetti Sept. 16, 1952 2,677,784 Jacobson May 4, 1954 2,692,355 Sickles Oct. 19, 1954 2,694,784 Reinhard Nov. 16, 1954 2,719,252 Margolis Sept. 27, 1955 2,787,743 Hultgren Apr. 2,. 1957 2,817,782 Over Dec. 24, 1957 2,886,741 Kongable May 12, 1959 2,900,564 Barkow Aug. 18, 1959

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