GB2306254A

GB2306254A - Flyback transformer coil structure

Info

Publication number: GB2306254A
Application number: GB9621301A
Authority: GB
Inventors: Jong-Dae Kim; Yong-Hee Kim; Ha-Eun Nam
Original assignee: Daewoo Electronics Co Ltd
Current assignee: WiniaDaewoo Co Ltd
Priority date: 1995-10-12
Filing date: 1996-10-11
Publication date: 1997-04-30
Also published as: TW331968U; AU7340796A; ID16175A; KR970023496A; GB9621301D0; WO1997014170A1

Abstract

A flyback transformer coil structure comprises plural layers in which each layer 60 comprises a spiral conductive coil pattern 64 formed on an insulating sheet 62 and each of said layers 60 is separated by an insulating member 70. The insulating sheets 62 and insulating members 70 may be formed by a polyamide film with a thickness of less than 25 microns. These may include a central hole 62a for receiving a magnetic core 80. The conductive pattern 64 may be formed with a width in the range of 40 to 100 microns. These patterns 64 may be connected to terminals and leads which allow the patterns to be interconnected in series.

Description

Coil Winding Structure of Flvback Transformer BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil winding structure of a transformer, and more particularly, to a coil winding structure of a flyback transformer for applying high-voltage current to a cathode-ray tube.

2. Description of the Prior Art Generally, a cathode-ray tube includes an electron gun emitting thermal electron beam and a photosensitive screen producing desired colors and images by the emitted electron beam. The photosensitive screen is coated with a combination of R, G and B type fluorescent materials. Also the cathode-ray tube is provided with a deflection coil, a focusing coil and an accelerating coil, etc., for controlling the emitted electron beam.

Typically, the cathode-ray tube requires a high-voltage of 25,000 V or so for deflecting and focusing the electron beam, and this high voltage current is generated by a flyback transformer and applied to the cathode-ray tube.

FIG. 1 is a perspective view illustrating an exploded state of a conventional flyback transformer, which will be described below.

As illustrated in FIG. 1, the conventional flyback transformer includes a casing 10 having a through-hole 12, a cylindrical secondary coil assembly 30 inside the casing 10, a cylindrical primary coil assembly 20 inserted into the secondary coil assembly 30, a magnetizable core 40 inserted into the primary coil assembly 20, an anode cap 14 attached to the secondary coil assembly 30, a cover 50 for the casing 10, and a condenser 52 inside the cover 50, etc.

The primary and secondary coil assemblies 20, 30 respectively consist of an insulating bobbin 24, 34 and primary and secondary coil windings 22, 32 around the bobbins 24, 34. All turns of the coil windings 22, 32 are insulated from each other.

A voltage applied to the flyback transformer is rectified by the condenser 52, flows to the primary coil assembly 20, and consequently to the primary coil winding 22.

The voltage applied to the primary coil winding 22, that is, a primary voltage, provides a large secondary voltage by mutual induction effect. As is well known, the value of the secondary voltage is determined depending on the ratio of the number of turns of the secondary coil winding 32 to that of the primary winding 22. Thereafter, the induced secondary voltage is applied through the anode cap 14 to the cathode-ray tube and then functions by emitting, accelerating, and focusing the electron beam.

In the above-described conventional flyback transformer, however, achieving uniformity in the characteristics thereof is not easy. Namely, in the coil winding process, the adjacent coil turns are very likely to overlap or separate from each other. Therefore, all of those problems lead to variation or fluctuation in the characteristics of the flyback transformer, consequently resulting in poor high voltage regulation thereof.

Furthermore, the demand for large sized cathode-ray tubes has increased, and therefore various devices for supplying voltage to the cathode-ray tube, especially the flyback transformer which requires a greater number of turns in the coil windings has lead to a resultant increase in the overall size of the flyback transformer.

SUMMARY OF THE INVENTION To solve the above problems, an object of the invention is to provide a new coil winding structure of a flyback transformer for achieving uniformity in the characteristics of the flyback transformer and also the compactness thereof.

To achieve the object of the invention, there is provided a coil winding structure of a flyback transformer, which comprises a plurality of layers of a conductor coil pattern sheet member which includes an insulating sheet and a spiral conductor coil pattern formed thereon, an insulating member interposed between the adjacent layers of the conductor coil pattern sheet member, and a connection means for electrically connecting the spiral conductor coil patterns.

The spiral conductor line of the spiral conductor coil pattern has a width of from about 40 to about 100 microns, and the insulating sheet has a thickness of less than about 25 microns.

The connection means is lead wires attached to a lead terminal and an end terminal of the spiral conductor coil patterns. Preferably, the lead wires are connected so that all of the spiral conductor coil patterns can be electrically connected in series with each other.

The conductor coil pattern sheet member includes a center hole for inserting a magnetizable core.

BRIEF DESCRIPTION OF THE DRAWINGS The above, other features and advantages of the invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the following drawings in which FIG. 1 is a perspective view showing an exploded state of a conventional flyback transformer.

FIG. 2 is a perspective view showing an exploded state of a preferred embodiment of the invention; FIG. 3 is a sectional side view showing the layered configuration of the embodiment in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, the invention will be described in further detail by way of a preferred embodiment with reference to the accompanying drawings.

FIG. 2 illustrates perspectively an exploded state of a coil winding structure of a flyback transformer(hereinafter, referred to as "FBT") according to this invention. As shown in the figure, the coil winding structure basically comprises a plurality of layers of a conductor coil pattern sheet member 60.

As illustrated in FIG. 2, the conductor coil pattern sheet member 60 includes a thin insulating sheet 62 and a spiral conductor coil pattern 64 formed thereon. The spiral conductor coil pattern 64 includes a pair of lead wires 68a, 68b attached respectively to a lead terminal 66a and an end terminal 66b of the coil pattern 64. The lead wires 68a, 68b are for electrical connection between the adjacent spiral conductor coil patterns 64, as described hereinafter.

The insulating sheet 62, which substantially bears the spiral conductor coil pattern 64, may be made from thin insulating materials such as polyimide film. The thickness of the insulating sheet 62 is preferably less than about 25 microns. It is desirable that the conductor line of the spiral conductor coil pattern 64 be very fine, preferably in the range of from about 40 to about 100 microns. This very fine configuration of the spiral conductor coil pattern 64 may be obtained by using a conventional process such as photolithograpy, etc. as used in the manufacture of a printed circuit board.

The conductor coil pattern sheet member 60 is provided with a hole 62a in the center thereof for subsequently inserting a magnetizable core 80, as illustrated in FIG. 2.

Also, the coil winding structure of the invention includes an insulating member 70, which is interposed between the adjacent layers in the multi-layered conductor coil pattern sheet members 60 and functions as an electrical insulator among the conductor coil pattern sheet members 60.

The insulating member 70 may be made from thin insulating materials such as a polyimide film, as is similar to the above insulating sheet 62. The insulating member 70 may be interposed between the conductor coil pattern members 60 concurrently with layering those, or pre-attached over the conductor coil pattern sheet members 60 before layering.

FIG. 3 is a sectional side view showing the layered configuration of the coil winding structure according to the invention. As illustrated in the figure, the conductor coil pattern sheet member 60 and the insulating member 70 are layered one after the other.

As illustrated in FIGS. 2 and 3, all of the spiral conductor coil patterns 64 are electrically connected with each other.

As described in the above, the conductor coil pattern sheet member 60 includes a pair of lead wires 68a, 68b, which are attached to the lead terminal 66a and the end terminal 66b of the spiral conductor coil pattern 64. In this embodiment, the lead wire 68a is attached to the lead terminal 66a from beneath the insulating sheet 62 to avoid electrical contact with the spiral conductor coil pattern 64.

Also, the spiral conductor coil pattern 64 is formed clockwise and outwards from the center of the insulating sheet 62. Therefore, in order that all the spiral conductor coil patterns 64 are electrically connected in series with each other, it is desirable that the lead wire 68a attached to the lead terminal 66a should be connected with the lead wire 68b attached to the end terminal 66b of the lower layer, and the lead wire 68b attached to the end terminal 66b should be connected with the lead wire 68a attached to the lead terminal 66a of the upper layer, as illustrated with a dotted line in FIG. 2.

In the embodiment as illustrated in FIGS. 2 and 3, the coil winding structure of the invention comprises only three layers of conductor coil pattern sheet members 60, but a greater number of the conductor coil pattern sheet members 60 may be layered, if desired. Therefore, the inventive coil winding structure provides the same effect as in a conventional coil winding assembly, which is made by repeatedly winding a very fine conductive wire, for example, a copper wire of a diameter in a range from 40 to 100 microns.

As clearly described above, the coil winding structure of FBT according to the invention does not need large bobbins 24, 34 as illustrated in FIG. 1 of the prior art because the number of turns of the coil windings can be considerably increased without increasing the overall size of the FBT, even if the FBT requires a greater number of turns of coil windings.

Also, the coil winding structure of the invention includes a plurality of the conductor coil pattern sheet members 60, which are uniformly and regularly layered.

Furthermore, the conductor coil pattern sheet member 60 includes the spiral conductor coil pattern 64 of which the conductor line is very fine and uniformly formed. Therefore, all of these features naturally result in uniformity in the functional characteristics of FBT.

While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A coil winding structure of a flyback transformer comprising: a plurality of layers of a conductor coil pattern sheet member, the conductor coil pattern sheet member including an insulating sheet and a spiral conductor coil pattern formed thereon; an insulating member interposed between the adjacent layers of the conductor coil pattern sheet member; and a connection means for electrically connecting the spiral conductor coil patterns.

2. The coil winding structure as claimed in claim 1, wherein the spiral conductor line of the spiral conductor coil pattern has a width of from about 40 to about 100 microns.

3. The coil winding structure as claimed in claim 1, wherein the insulating sheet has a thickness of less than about 25 microns.

4. The coil winding structure as claimed in claim 1, wherein the connection means is lead wires attached to a lead terminal and an end terminal of the spiral conductor coil patterns.

5. The coil winding structure as claimed in claim 4, wherein the lead wires are connected so that all of the spiral conductor coil patterns can be electrically connected in series with each other.

6. The coil winding structure as claimed in claim 1, wherein the conductor coil pattern sheet member is a conductor coil pattern sheet member having a center hole for inserting a magnetizable core.