GB2269477A - CRT deflection yoke with printed circuit board - Google Patents

Abstract

A mounting board 13 for two auxiliary coils 4, 5 in a deflection yoke is constructed from a printed board, and the auxiliary coils mounted on the front side of the printed board on which contact patterns are not formed are wired with leads to printed contacts formed on the reverse side of the printed board. Further, horizontal deflection and/or vertical deflection coils on a terminal board 7 in the deflection yoke are also wired with leads to the same printed board. A conical separator 1 and guide cylinder 1g are of split construction for placement around an electron gun and to mount the vertical deflection coil 2 on ferrite cores 9. The construction results in reduced routing lead lengths. <IMAGE>

Description

DEFLECTION YOKE The present invention relates to a deflection yoke that is primarily used, for example, in a color cathode-ray tube of a television receiver.

In the accompanying drawings Fig. 1 is a perspective view showing a prior art deflection yoke. In the figure, the reference numeral 1 designates a separator, 2 is a vertical deflection coil, 3 is a mounting board, and 4 and 5 indicate auxiliary coils.

The following description assumes the use of coma correction coils as a typical example of the auxiliary coils. The separator 1 is formed from a plastic or other insulating material in a substantially hollow, conical shape. Inside the separator 1 are mounted horizontal deflection coils (not shown), while the vertical deflection coils 2, which are formed from coils wrapped around ferrite cores 9, are mounted on the outside of the separator 1 in such a manner as to follow the curvature of the circumferential wall thereof.

A flange la is fitted around the periphery of each of the smaller and larger diameter ends of the separator 1 (only the flange on the larger diameter ends is shown). On the smaller diameter end, there is also mounted a guide cylinder 1g which is fitted into the mounting board 3 attached to the flange mounted on the smaller diameter end.

The mounting board 3 is placed perpendicularly to the axis of the separator 1. The two sets of auxiliary coils, 4 and 5, each set consisting of three coils, are mounted on the surface of the mounting board 3 in such a manner as to face each other across the guide cylinder ig.

The auxiliary coils 4, 5 are formed from coils 4b, 5b wrapped around the prongs of forked magnetic cores 4a, 5a each core consisting of three prongs. The numerals 7 and 8 indicate terminal boards which are attached at an angle to both edges of the mounting board 3 and extending outwardly along the surfaces of the vertical deflection coils 2.

Leads from the horizontal deflection coils are connected to the terminal board 7, while leads from the vertical deflection coils 2 and leads from the auxiliary coils 4 and 5 are connected to the terminal board 8 (all these leads are not shown). The terminal boards 7 and 8 are then wired to the main unit of a television receiver not shown. The leads from the auxiliary coils 4 and 5 are routed along the surface of the mounting board 3, passed through guide holes 3g, and wrapped around pins 8a on the terminal board 8 for connection by soldering or other means.

The deflection yoke of the above construction is secured onto the neck of a cathode ray tube with the guide cylinder ig positioned forwardly.

In the above-described prior art deflection yoke, since the distance from the auxiliary coils 4, 5 to the respective pins 8a on the terminal board 8 varies from coil to coil, leads of different lengths are needed, and each lead requires a different routing pattern. Not only do the coils 4b, 5b require the use of leads of different lengths; in assembling the auxiliary coils 4 and 5, it is required that the coils 4b and 5b with leads of different lengths should be accurately secured in position. Furthermore, prefinishing such as adjusting the length of each lead, grinding, etc. is required before mounting. Hence, the above deflection yoke involves such problems as increased complexity of the assembling and wiring processes, time-consuming assembling work, and increased possibility of miswiring.

In view of the above problems, it is a primary object of the invention to provide a deflection yoke which permits the use of leads of identical length on auxiliary coils, does not require distinguishing individual coils in assembling the auxiliary coils, improves the assembling work efficiency, and eliminates the possibility of miswiring.

According to a first preferred mode of the invention, there is provided a deflection yoke which has auxiliary coils mounted on a mounting board attached to a coil separator, the auxiliary coils being wired with leads to a terminal board, wherein the mounting board is constructed from a printed board that also serves as the terminal board, and the leads from the auxiliary coils are connected to the mounting board. With this construction, all individual auxiliary coils can be standardized and need not be distinguished from each other in assembling, thus standardizing the work and hence improving the assembling work efficiency.

According to a second preferred mode of the invention, there is provided a deflection yoke which has horizontal deflection and vertical deflection coils and a terminal board attached to a coil separator that carries thereon auxiliary coils mounted on a mounting board, the horizontal deflection and vertical deflection coils and the auxiliary coils being wired with leads to the terminal board, wherein the mounting board on which the auxiliary coils are mounted is constructed from a printed board that also serves as the terminal board, and the leads from the auxiliary coils and the leads from the vertical deflection and/or horizontal deflection coils are connected to the mounting board.Since the leads from the auxiliary coils and the leads from the vertical deflection and/or horizontal deflection coils are all connected to the mounting board, this construction permits a reduction in the number of components as well as in the lead length, thereby achieving a further reduction in the number of assembling and wiring steps.

The invention will be further described-by way of non-limitative example in the following detailed description with reference to the accompanying drawings, in which: Fig. 1 is a perspective view showing a prior art deflection yoke.

Fig. 2 is à perspective view showing a deflection yoke according to the invention.

Fig. 3(a) is a perspective view showing auxiliary coils in the deflection yoke of the invention.

Fig. 3(b) is a perspective view showing a mounting board in the deflection yoke of the invention.

Fig. 3(c) is an enlarged rear view showing a portion of the mounting board in the deflection yoke of the invention.

Fig. 4 is a perspective view showing the auxiliary coils mounted on the mounting board in the deflection yoke of the invention.

Fig. 5 is an enlarged perspective view showing the smaller diameter end of a separator in the deflection yoke of the invention.

An embodiment of the invention will now be described below with reference to the accompanying drawings.

Fig. 2 is a perspective view showing a deflection yoke according to the invention. In the figure, the reference numeral 1 designates a separator, 2 is a vertical deflection coil, 13 is a mounting board1 and 4 and 5 denote auxiliary coils. The separator 1 is formed from a plastic or other insulating material in a substantially hollow, conical shape. A flange la is fitted around the periphery of the larger diameter end of the separator 1; likewise, around the periphery of the smaller end of the separator 1 are fitted flanges 1b and Ic (see Fig. 5) along with a guide cylinder lg. The flanges la, Ib, and lc, the guide cylinder Ig, and the hollow conical body are each split into two sections along the axis of the separator 1. In the assembling process, the two split sections are joined together to form an integral construction.

Inside of the circumferential wall of the separator 1 are mounted horizontal deflection coils (not shown), while the vertical deflection coils 2, which are formed from coils wrapped around permeability ferrite cores 9, are mounted on the outside of the circumferential wall. The guide cylinder ig is mounted extending axially from the smaller diameter end of the separator 1, and the spaced parallel flanges 1b and lc are fitted around the circumferential wall of the guide cylinder 1g and oriented in a direction perpendicular to the axis of the separator 1.

On the outside surface of the flange lc, stepped engaging pawls le protruding outwardly are formed at four places around the guide cylinder 1g so that the mounting board 13 with the auxiliary coils 4 and 5 mounted thereon can be fitted onto the engaging pawls le. The numeral 7 indicates a terminal board for the horizontal defection coils.

Fig. 3(a) is a perspective view showing the auxiliary coils, Fig. 3(b) is a perspective view showing the mounting board, and Fig. 3(c) is an enlarged view showing a rear portion of the mounting board where cutouts are formed. As shown in Fig. 3(a), the auxiliary coils 4, 5 are constructed from coils 4b, 5b wrapped around the prongs of forked magnetic cores 4a, 5a each core consisting of three prongs.

Leads 4c, Sc from the ends of each of the coils 4b, 5b are drawn out on the base side of the prongs of the magnetic cores 4a, 5a.

The mounting board 13 is constructed from a printed board having a pattern of printed wiring formed on its reverse side. As shown in Fig 3(b), the mounting board 13 is a rectangular plate whose four corners are chamfered and whose area size is slightly larger than the mounting board 3 shown in Fig. 1. A circular opening 13a through which the guide cylinder 1g is to be fitted is formed in the mounting board 13 at a place nearer to one of the shorter sides of the rectangle. On opposite sides across the opening 13a are formed rectangular openings 13b, 13c, and outwardly of these openings 13b, 13c are formed a plurality of cutouts 13d, 13e, respectively.As shown in Fig. 3(c), printed contacts 13f to which the leads 4c, Sc from the coils 4b, 5b are to be connected are formed on the reverse side of the printed board near the cutouts 13d, 13e. The reference numeral 13h indicates engaging holes into which the stepped engaging pawls le protruding from the flange lc are to be fitted.

Referring now to Figs. 3 to 5, we will describe an assembling procedure for the major parts of the deflection yoke according to the present invention. The component members of the separator 1, which are respectively split into two sections along the axial direction, are joined together face to face, as shown in Fig. 5, in such a manner as to envelope the horizontal deflection coils therein. As a result, the flanges 1b and Ic on the smaller diameter end become fitted around the outer circumferential surface of the guide cylinder lg with a prescribed spacing provided between the two flanges 1b and lc. Next, the vertical deflection-coils 2 are mounted on the outside of the separator 1.

In the meantime, the auxiliary coils 4 and 5 are assem bled as shown in Fig. 3(a). Then, the auxiliary coils 4 and 5 are fitted into the rectangular openings 13b and 13c in the mounting board 13 with the tip of each prong of the magnetic cores 4a and 5a pointing toward the opening 13a, thus mounting the coils 4b and 5b in position. The leads 4c and Sc are then run through the respective cutouts 13d and 13e and routed to the reverse side of the mounting board 13 for connection by soldering to the printed contacts 13f shown in Fig. 3(c).

Fig. 4 is a perspective view showing the auxiliary coils 4 and 5 thus mounted on the mounting board 13. Next, the mounting board 13 with the auxiliary coils 4 and 5 mounted thereon is mounted onto the flange lc attached to the smaller diameter end of the separator 1. More specifically, the stepped engaging pawls le formed on the flange lc are fitted into the engaging holes 13h formed in the mounting board 13 while the opening 13a of the mounting board 13 is being fitted onto the guide cylinder 1g extending outwardly from the flange Ic. As a result, the underside of the mounting board 13 abut against the stepped portions of the engaging pawls le, thus positioning the mounting board 13 above the flange lc with a prescribed spacing provided therebetween, as shown in Fig. 2.The mounting board 13 is then secured integrally in position using an adhesive, cover case, etc.

The leads from the horizontal deflection coils are connected to the terminal board 7, and the leads from the vertical deflection coils 2 are connected to the mounting board 13. Finally, the deflection yoke assembly is secured onto the neck of a cathode ray tube with the guide cylinder 1g positioned forwardly.

In the above embodiment, the leads from the horizontal deflection coils are connected to the terminal board 7, but in an alternative construction, these leads may be connected to the mounting board 13.

As described, according to the deflection yoke of the invention, the mounting board for the auxiliary coils is constructed from a printed board, and the leads from the auxiliary coils are connected to the mounting board. This construction serves to drastically reduce the lead length, and at the same time, allows the use of lead of identical length, thus making it possible to standardize the specification of the auxiliary coils and to drastically reduce the number of manufacturing and assembling steps.

Furthermore, since the auxiliary coil mounting board is constructed from a printed board, and the leads from the auxiliary coils and the leads from the vertical deflection and/or horizontal deflection coils are connected to this printed board, the construction serves to drastically reduce the routing length of the leads, simplify the assembling work, and prevent miswiring.

As this invention may be embodied in several forms without departing from the essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the -scope of the invention is defined by the appended claims.

Claims (10)

CLAINS

1. A deflection yoke for a cathode ray tube, comprising: a coil separator; auxiliary coils; and a printed circuit board attached to the coil separator having the auxiliary coils mounted thereon with leads from the auxiliary coils connected to contacts on the printed circuit board.

2. A deflection yoke according to claim 1, wherein the auxiliary coils are mounted on the front side of the printed circuit board, and the printed contacts for connection with the leads from the auxiliary coils are formed on the reverse side of the printed circuit board.

3. A deflection yoke according to claim 1 or 2, wherein cutouts are formed at edges of the printed circuit board, and the leads from the auxiliary coils are run through the cutouts for connection to the printed contacts.

4. A deflection yoke according to claim 1, 2 or 3, further comprising: horizontal deflection coils mounted inside the coil separator; and vertical deflection coils mounted outside the coil separator.

5. A deflection yoke according to claim 4, wherein the horizontal deflection and/or vertical deflection coils are wired with leads to the printed circuit board.

6. A deflection yoke according to claim 5, wherein printed contacts are formed only on the reverse side of the printed board, and the auxiliary coils are mounted on the front side of the printed board on which the printed contacts are not formed.

7. A deflection yoke according to claim 1, 2 or 3, further comprising: horizontal deflection coils; and vertical deflection coils; the coil separator separating the horizontal deflection coils from the vertical deflection coils; and wherein the vertical deflection and/or horizontal deflection coils are wired with leads to the printed board.

8. A deflection yoke constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figures 2 to 5 of the accompanying drawings.

9. A C.R.T. including a deflection yoke in accordance with any one of the preceding claims.

10. A television or video monitor including a C.R.T. in accordance with claim 9.