JP2562587Y2 - Flyback transformer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flyback transformer in which a resistor circuit for adjusting and setting a focus adjustment voltage is connected to a middle stage of a high voltage coil.

[0002]

2. Description of the Related Art FIG. 4 shows a circuit of a general flyback transformer in which a high voltage coil is laminated.
In the figure, a low-voltage coil 2 is fitted to a core 1, and a high-voltage coil 3 is fitted outside the low-voltage coil 2.

[0003] A high-voltage coil 3 is provided on the winding body of a high-voltage bobbin via an interlayer insulating material such as an insulating film.
a to 4g are laminated, and a forward rectifier diode 5a for adding a voltage to the winding end of the coil of each coil 4a to 4f and the winding start of the coil 4b to 4g of the next layer.
Through 5f connected in series. The output terminal of the final stage coil section 4g is connected to the anode of a cathode ray tube (not shown) via a high voltage rectifier diode 6.
The resistance circuit of the focus pack 7 is connected to the middle part of the high voltage coil 3, in the example of FIG. 4, to the cathode side of the rectifier diode 5 c via a focus adjustment voltage terminal.
This resistance circuit has a focus adjustment resistor 8 and a screen adjustment resistor 10, and the focus adjustment resistor 8
The focus adjustment voltage is set by slidingly adjusting the slide terminal 11 of the screen adjustment resistor, and the set focus adjustment voltage is applied to the focus electrode of the cathode ray tube. The screen adjustment voltage is set by slidably adjusting, and the set screen adjustment voltage is applied to the screen electrode of the cathode ray tube.

[0004]

Generally, when the brightness of the screen of the cathode ray tube changes from, for example, a dark screen to a bright screen, a high-voltage output current flows from the high-voltage coil 3 to the cathode-ray tube, and the high-voltage output voltage E _H drops. Phenomenon occurs.
In this case, the focus adjustment voltage E _F also high output voltage E _H
It changes following the change of. When the rate of change of ratio and focus adjustment voltage E _F of the change in the high output voltage E _H is equal, i.e., the focus is blurred when the focus adjustment voltage E _F is completely follow the change of the high output voltage E _H A good screen can be obtained without any problem, but actually, the resistance circuit of the focus pack 7 is
Since a part of the current from the current diode 5c flows,
Regulator of the focus adjustment voltage E _F and high output voltage E _H
Shon characteristic difference occurs, followability of the focus adjustment voltage E _F to changes in the high-voltage output voltage E _H is deteriorated, 2
Of as shown by the curve F, fluctuates ratio is large and the focus adjustment voltage E _F and high output voltage E _H by the magnitude of the high voltage output current and changes, for example from a bright screen to a dark screen, the focus of the focus The problem of blurring occurs.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to improve the followability of a focus adjustment voltage with respect to a high-voltage output voltage and to achieve focus focusing by changing the luminance of a screen of a cathode ray tube. An object of the present invention is to provide a flyback transformer that does not blur.

[0006]

The present invention is configured as follows to achieve the above object. That is, in the present invention, a high-voltage coil is laminated and wound on a high-voltage bobbin via an interlayer insulating material, and the winding end of the coil of each layer is added to the winding start of the coil of the next layer and the pulse voltage in the forward direction. In a flyback transformer that is connected via a rectifier diode and has a focus adjustment voltage terminal in the middle stage of the high voltage coil,
Between the cathode side of at least one rectifier diode connected to the coil section of each of the second and higher layers and the ground
Is connected to a capacitance adjusting capacitor that adjusts the distributed capacitance of the coil portion of each layer by making the potential on the cathode side substantially zero potential in an alternating current manner.

[0007]

[Action] In the present invention having the above structure, the fly-back transformer is boosting the flyback pulses applied to the low pressure coil side by the coil portions of the high voltage coil, this time, each coil section, the first stage (first layer Eye) coil part
In this case, an inverted pulse having a polarity opposite to that of the flyback pulse is generated on the cathode side of the rectifier diode as shown in FIG. In the present invention, the capacitance adjustment capacitor is connected to the cathode side of at least one rectifier diode connected to the coil portion of each stage of the second stage (second layer) or higher of the high-voltage coil. AC manner to substantially zero potential but the cathode potential of the rectifying diode connected
It can, to abolish inverted pulse of the part
it can. The connection of the capacitance adjustment capacitor, affect other coil portion minutes to change the distributed capacitance between the coil portions component and ground. By utilizing the change in the distribution capacitance, the distribution capacitance of the high-voltage coil is adjusted to an ideal distribution capacitance, so that the followability of the focus adjustment voltage to the high-voltage output voltage is improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same names as those in the conventional example, and detailed description thereof will be omitted. FIG. 1 shows a circuit configuration of an embodiment of a flyback transformer according to the present invention. The feature of this embodiment is that the second and subsequent layers are viewed from the low voltage end of the high voltage coil 3.
Rectifier diodes suitable stage of the coil portion 4 b to 4 g of the above 5
One end of the capacitance adjusting capacitor 13 is connected to the cathode side of b to 5f, in FIG. 1, the cathode side of the rectifier diode 5b in the second stage, and the other end of the capacitance adjusting capacitor 13 is connected to the ground. Structures other than the above are the same as those of the conventional example. The capacity adjusting capacitor 13 has a capacity of 10 to 1000 PF which has a sufficient withstand voltage with respect to the voltage at the connection point.

As described above, by connecting the capacitance adjusting capacitor 13 to the cathode of the rectifier diode 5b,
The potential of the connection portion becomes substantially zero potential in terms of AC, whereby the inversion pulse generated in the coil portion 4b almost disappears.
You. Due to the connection of the capacitor 13 , the influence spreads to other coil portions, and the distributed capacitance between each of the coil portions 4a to 4g and the ground changes. When the distributed capacitance between each coil unit and the ground changes, the regulation characteristic of each coil unit also changes, and the state in which the focus adjustment voltage follows the change in the high-voltage output voltage changes.

FIG. 2 is a graph showing the measurement of the followability of the focus adjustment voltage when one end of the capacitance adjustment capacitor 13 is connected to the cathodes of the rectifier diodes 5a to 5d at different positions. 13 is connected to the ground or a predetermined potential portion). Curve A
Is a case where the capacity adjusting capacitor 13 of 100 PF is connected to the cathode of the rectifier diode 5a of the first stage, and the curve B is
The curve C shows the characteristic when the capacity adjusting capacitor 13 of 0 PF is connected to the cathode of the rectifier diode 5b of the second stage.
Curve D when the capacitance adjusting capacitor 13 of FIG.
Shows the characteristics when a 100 PF capacitance adjusting capacitor 13 is connected to the cathode of the fourth stage rectifier diode 5d. Further, the curve E uses two 100 PF capacitance adjusting capacitors 13 and uses one capacitor. The graph shows the characteristics when the second capacitance adjustment capacitor is connected to the cathode of the second-stage rectifier diode 5b and the second capacitance adjustment capacitor is connected to the cathode of the third-stage rectifier diode 5c. in this way,
The distributed capacitance between each of the coil units 4a to 4g and the ground varies depending on which one or more capacitance adjusting capacitors 13 are used and which rectifier diodes 5a to 5f of each stage are connected to the cathode side. In this case, the cathode of the first-stage rectifier diode 5a
A with the capacitance adjusting capacitor 13 connected to the other curve B
E is significantly worse than the first-stage coil portion 4a.
Capacitor adjusting capacitor 13 because the end is connected to ground
It is thought that the rate of change of distributed capacitance due to connection of
Can be Therefore, when the capacitance adjustment capacitor 13 is connected, the high-voltage output voltage E _H and the focus adjustment voltage E _F
Is connected to the rectifier diode of the stage where the change of the ratio becomes the smallest.

The present invention is not limited to the above embodiment, but can take various embodiments.

[0012]

According to the present invention, a capacitor is provided between at least one cathode side of a rectifier diode connected to the coil portion of each of the second and higher layers as viewed from the low voltage end of a high-voltage coil wound in a stack and the ground. Since the adjustment capacitor is connected, the potential at the connection point can be set to approximately zero potential in an AC manner, and the inversion pulse generated at that portion can be eliminated. As a result, the coil section and the arc of each layer of the high-voltage coil are
It is possible to adjust the distributed capacitance between the scan, which makes it possible to greatly increase the followability of the focus adjustment voltage for the change of the high output voltage, that the focus of the focus blurred by the brightness change of the screen of a cathode ray tube It is possible to provide a flyback transformer having excellent focus characteristics without any problem.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a flyback transformer according to the present invention.

FIG. 2 is a measurement graph showing, in comparison with a conventional example, a tracking characteristic of a focus adjustment voltage when a connection position of a capacitance adjustment capacitor is changed in the present embodiment.

FIG. 3 is a waveform diagram showing a flyback boosting pulse and an inversion pulse generated in each coil portion of the stacked type high voltage coil.

FIG. 4 is a circuit diagram of a conventional general flyback transformer in which a high-voltage coil is a stacked type and a resistance circuit of a focus pack is connected from the middle stage.

[Explanation of symbols]

 3 High voltage coil 4a-4g Coil section 5a-5f Rectifier diode 7 Focus pack 8 Focus adjustment resistor 10 Screen adjustment resistor 13 Capacitance adjustment capacitor

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-49-88421 (JP, A) JP-A-54-82121 (JP, A) JP-A-63-144766 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] 1. A high voltage coil is wound around a high voltage bobbin with an interlayer insulating material interposed therebetween, and a winding end of a coil of each layer is forward rectified by adding a pulse voltage to a winding start of a coil of a next layer. The flyback transformer is connected via a diode and has a focus adjustment voltage terminal in the middle stage of the high voltage coil.
Cathode and A of at least one rectifier diode which is connected to the coil portion of the second layer or more layers when viewed from圧端
Flyback transformer between over scan, wherein the capacitance adjustment capacitor for adjusting the distributed capacitance of the coil part of each layer in the alternating manner substantially zero potential the potential of the cathode side is connected.