US3846666A

US3846666A - High voltage circuit of color television receiver

Info

Publication number: US3846666A
Application number: US00329867A
Authority: US
Inventors: N Suzuki; T Nishihara; G Miyazaki
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1972-02-04
Filing date: 1973-02-05
Publication date: 1974-11-05
Anticipated expiration: 1991-11-05
Also published as: JPS4882725A

Abstract

In a high voltage circuit of a color television receiver, constructed such that the voltage of the secondary winding of a fly-back transformer is converted into high DC voltages by an n-ple voltage rectifier, and that the output voltage Eb of the n-th stage of the rectifier circuit is applied to the phosphor screen of a post-deflection focusing type or after-focusing type Braun tube, while the output voltage Em of the m-th stage (m < n) is applied to the shadow mask thereof, a high voltage circuit wherein a voltage stabilizing element is incorporated between the output terminal of the n-th stage of the n-ple voltage rectifier circuit and ground, and current is kept steadily flowing through the element, whereby the ratio between the voltages Eb and Em, that is Eb/Em, is held substantially constant against load fluctuations in the n-ple voltage rectifier circuit.

Description

United States Patent [191 Suzuki et al.

HIGH VOLTAGE CIRCUIT OF COLOR TELEVISION RECEIVER Inventors: Nobuyuki Suzuki; Toyotaro Nishihara, both of Yokohama; Gentaro Miyazaki, Fujisawa, all of Japan Assignee: Hitachi, Ltd., Tokyo, Japan Filed: Feb. 5, 1973 Appl. No.: 32 9,86 7 W W 7 Foreign Application Priority Data Feb. 4, 1972 Japan ..47-12222 US. Cl 315/27 TD, 315/29 Int. Cl. H0lj 29/70 Field of Search 315/27 TD, 27 R, 28, 29,

References Cited UNITED STATES PATENTS Primary Examiner-Richard A. Farley Assistant Examiner-J. M. Potenza Attorney, Agent, or Firm-Craig & Antonelli [5 7 ABSTRACT In a high voltage circuit of a color television receiver, constructed such that the voltage of the secondary winding of a fly-back transformer is converted into high DC voltages by an n-ple voltage rectifier, and that the output voltage E, of the n-th stage of the rectifier circuit is applied to the phosphor screen of a post-deflection focusing type or after-focusing type Braun tube, while the output voltage E,, of the m-th stage (m n) is applied to the shadow mask thereof, a high voltage circuit wherein a voltage stabilizing element is incorporated between the output terminal of the n-th stage of the n-ple voltage rectifier circuit and ground, and current is kept steadily flowing through the element, whereby the ratio between the voltages E and E,,,, that is E,,/E,,,, is held substantially constant against load fluctuations in the n-ple voltage rectifier circuit.

17 Claims, 17 Drawing Figures Em Ef 30 PATENTEDIIUV 51914 3. 846.666

sum

1 or 5 FIG. I PRIOR ART FIG. 2(AI K) O LEVEL FIG. 2(B) FIG. 2(CI iEAGI ---LA| O LEVEL PATENTEDunv 51974 3.846366 QHEU 30F 5 FIG. 6(A) FIG. 6(8) Neg o LEVEL o LEVEL FIG. 8 v 16 F|G.9

1 HIGH VOLTAGE CIRCUIT OF COLOR TELEVISION RECEIVER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage circuit of a color television receiver, and more particularly to a high voltage circuit by which the ratio between voltages applied to a shadow mask and to a phosphor screen in an after-focusing type Braun tube is always held constant.

2. Description of the Prior Art In prior art shadow mask type color television receivers, the transmissivity of an electron beam permeating through a shadow mask is low, and the luminance is accordingly low. In order to raise the luminance, the voltage applied to the shadow mask should be made higher. In consequence, the current to be supplied to the deflecting yoke should be also increased, This is a serious disadvantage of the prior art color television receivers.

Using an after-focusing type color Braun tube as is well known, it becomes possible to enhance the transmissivity of of the electron beam permeating through the shadow mask, and to attain a high luminance even if a very high voltage is not applied to the shadow mask itself. In this case, a voltage E, (approximately equal to the voltage E of a funnel portion) which is low as compared with the high voltage E,, of a phosphor screen is applied to the shadow mask. The use of the after-focusing type Braun tube is accordingly advantageous in that the current to be supplied to the deflecting yoke may also be small in comparison with that in the prior art. In the after-focusing type Braun tube, however, it is required to always maintain constant the voltage ratio E /E, between the phosphor screen voltage E,, and the shadow mask voltage E, (E,, E,,,) and the voltage ratio E /E, between the phosphor screen voltage E,, and the voltage E, applied to the funnel portion of the tube.

The reason is that, when the ratios E /E, and Eli/E! change due to the variation of luminance by brightness control or to non-uniformity in the characteristic of components, the postdeflection focusing is not effected as predetermined, leading to degradation in the color purity. Only very small changes are therefore allowable for E1,/E,,, and E,,/E;.

FIG. 1 shows a prior art high voltage circuit of a color television receiver. Referring to the figure, numeral 1 designates a fly-back transformer, which has a primary winding la and a secondary winding lb. As is well known, the primary winding la has a horizontal deflection output supplied thereto from a horizontal deflection circuit (not shown). A fly-back pulse appears in the secondary winding lb, and is converted into high DC voltages by means of an n-ple voltage rectifier circuit 2. The n-ple voltage rectifier 2 consists of diodes D D D and capacitors C,, C C and the details of the rectifier are omitted herefrom since it is a circuit which has been well known. A higher voltage is provided at an output terminal 2a than at an output terminal 2b of the circuit 2. The voltage E derived from the output terminal 2a is applied to a phosphor screen 3a of a Braun tube 3, while the voltage E,,, derived from the output terminal 2b is applied to a shadow mask 3b and a funnel portion electrode 30.

In the above circuit, pulses of a voltage waveform as shown in FIG. 2(A) are produced in the secondary winding lb of the fly-back transformer l. The waveform contains a fly-back pulse A and ringing pulses B.

' The shape and magnitude of the pulses A and B differ in dependence on the characteristic of the fly-back transformer, the construction of the n-ple voltage rectifier circuit, etc. However, even in case where the design is so made as to render the ringing pulses B as small as possible the pulses do not become null but exist, though slightly, on account of dispersions in the leakage inductance of the fly-back transformer, the values of the capacitors of the n-ple voltage circuit, the inductance and capacitance of the primary side of the flyback transformer, and so forth. In FIG. 2(A), the amplitude of the ringing pulse B is indicated by e;,.

On the other hand, the voltages E,, and E,,,, respectively,provided from the

output terminals

20 and 2b in FIG. 1 are represented by the following equations:

E,,,=m e,+(m l)e Accordingly, E,,/ E, becomes:

where n and m are the numbers of stages of voltage multiplication associated with the respective signals, and

e and e are the widths of the pulses in the secondary side winding of the fly-back transformer.

As previously stated, the ringing pulses cannot be made null, and therefore they exist, though slightly. Accordingly, when the high voltage load fluctuates, the tuning condition of higher harmonics changes. As illustrated in FIG. 2(B), therefore, the amplitude of the ringing pulse B changes. In consequence, the amplitude of the pulse e changes, the ratio e /e changes, and finally the value Eh/E", in equation (3) changes.

SUMMARY OF THE INVENTION It is accordingly the principal object of the present invention to provide a high voltage circuit which is constructed so that the voltage ratios E /E, and E /E, may be always held constant.

In order to accomplish the above-described object, the present invention consists of a high voltage circuit including a fly-back transformer and an n-ple voltage rectifier device connected on the secondary side of the transformer wherein, when the fly-back transformer is on the third harmonics tuning type, a high voltage stabilizing element is connected between the last stage or an intermediate stage of the voltage multiplication rectifier device and ground.

The present invention further consists of a high voltage circuit wherein, when the fiy-back transformer is of the fifth harmonics tuning type, a high voltage stabilizing element is connected between any desired stage of the n-ple voltage rectifier circuit and ground, or the load is connected through a high resistance.

The other objects and features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic circuit diagram of a prior art high voltage circuit of a color television receiver;

FIGS. 2(A), 2(3) and 2(C) are waveform diagrams of voltages in the secondary winding of a fly-back transformer;

FIGS. 3 and 4 are schematic circuit diagrams each showing an embodiment of a high voltage circuit according to the present invention;

FIGS. 5(A) and 5(8) are regulation voltage characteristic diagrams of voltages applied to the phosphor screen. respectively;

FIGS. 6(A) and 6(8) are waveform diagrams of voltages in the secondary winding of a fly-back transformer in the circuit of the present invention, respectively;

FIG. 7 is a schematic circuit diagram showing another embodiment of the high voltage circuit of the present invention;

FIG. 8 is a diagram of varying characteristics of the respective voltages of a phosphor screen, a shadow mask and a funnel portion of the tube versus the phosphor screen current;

FIG. 9 is a current-voltage characteristic diagram of a voltage stabilizing element;

FIG. 10 is a schematic circuit diagram showing a further embodiment of the present invention;

FIG. 11 is a sketch showing an example of the flyback transformer for use in the circuit of the present invention, and

FIGS. 12 and 13 are schematic circuit diagrams each showing a still further embodiment of the present invention.

PREFERRED EMBODIMENTS OF THE INVENTION In FIG. 3, showing an embodiment of the present invention, the same symbols are affixed to the same parts as in FIG. I, and the explanation of such parts therefore will be omitted. As apparent from FIG. 3, in the circuit arrangement of the present invention, a voltage stabilizing element 4 having a constant-voltage characteristic, such as a Zener diode, is connected between the output terminal 2a of any stage, for example, the final stage of the n-ple voltage rectifier circuit 2 and ground. A DC power source 5 is connected between one end of the secondary winding lb of the fly-back transformer l and ground. A capacitor 230 is also provided for tuning the secondary side of the transformer l to the third higher harmonics, while 24 designates a capacitor for making up for the capacity of the phosphor screen 3a.

In the post-deflection focusing type color television receiver, a current 1 flowing through the phosphor screen of the Braun tube 3 and a current I, flowing through the shadow mask 3b become I I, 0 when the luminance is minimized. Accordingly, when the luminance is varied from the minimum to the maximum, the output power of the n-ple voltage rectifier circuit 2 fluctuates as stated below.

1. In the case where the high voltage stabilizing element 4 is not included:

Output at Minimum Luminance, P,,,,,, 0

Output at Maximum Luminance, P',,,,,,, E 'l m m max 2. In the case where the voltage stabilizing element 4 is connected:

Output at Minimum Luminance,

P

15,, 1,,

Output at Maximum Luminance. P [5,, 1,, l;,,,' l,,,

b n m' m ma:

The difference between P,,,,,, and P is much smaller than that between P',,,;,, and P,,,,,,. That is, regarding the load fluctuation with the Braun tube side seen from the n-ple voltage rectifier circuit 2, the circuit shown in FIG. 3 has a load fluctuation which is a great deal smaller than that of the circuit in FIG. 1.

According to the circuit illustrated in FIG. 3, in the case where the same load fluctuation as in the circuit in FIG. 1 arises, the changes of the pulse amplitudes A e, and A e, are smaller, as shown in FIG. 2(C).

The reason is that, since the load current flows steadily through the voltage stabilizing element 4 in the circuit of FIG. 3, the conduction period of the diodes of the voltage multiplication rectifier circuit 2 is longer, with the result that e, and e are difficult to change for a given load fluctuation.

In other words, as between the case where the load fluctuation occurs from the state under which the load is zero [FIG. 2(8)] and the case where it arises from the state under which the load current of certain value is already flowing [FIG. 2(C)], the latter naturally provides smaller changes in e, and e As a result, the latter also provides smaller changes in E, and E,,,.

It is therefore possible to restrain the changes of e, and e to very small values and to reduce the variation of the ratio E /E in such way that a certain load current is previously caused to flow steadily by incorporating the high voltage stabilizing element 4.

In the circuit in FIG. 3, the DC power source 5 is connected between one end of the secondary winding lb of the flyback transformer l and ground. Letting E be the supply voltage of the DC source 5,

It is therefore possible to perform the fine adjustment of E /E by changing E.

Thus, the voltage ratio between the high voltages E and E,,,( E, can be selected at an adequate value, and can be held substantially constant, so that an afterfocusing type color television receiver with very stable color purity is realizable.

FIG. 4 is a circuit diagram showing another embodiment of the present invention. According to this embodiment, a capacitor 23b adapted to tune the secondary to the fifth higher harmonics is connected on the secondary side of the transformer 1, while a high resistance 4a is connected between the output terminal 2a of the n-ple voltage rectifier circuit 2 and ground.

While the circuit of FIG. 3 employs the fly-back transformer of the third harmonics tuning type, the regulation characteristic of the high output voltage of the voltage multiplication rectifier circuit 2 becomes as shown in FIG. 5(A) in the case of the fifth harmonics tuning type. The regulation characteristic of the high output voltage can be improved as illustrated in FIG. 5(B), in such a way that the high resistance 4a is incorporated as shown in FIG. 4 and that a current 1 is permitted to flow therethrough.

Herein, the high resistance 4a illustrated in FIG. 4 is a mere example of means for taking out a load from the n-ple voltage rectifier circuit 2. In order to achieve the characteristic as illustrated in FIG. 5(B), a high resistance may be inserted between the output of any stage in the n-ple voltage rectifier circuit and ground, so as to take out a load equivalent to E 'l Alternatively, a high resistance may be inserted between the output terminals of different stages of the rectifier circuit. In case of incorporating a high voltage stabilizing element, it is more convenient for the measurement of current and other operations that the element be inserted between a DC voltage part and ground.

With the fifth harmonics tuning system, the waveform of voltages in the secondary winding of the flyback transformer I becomes as illustrated by solid lines in FIG. 6(A). In comparison with the third harmonics tuning system with the like voltages shown by broken lines, the fifth harmonics tuning system can reduce the ratio e /e between the ringing pulse amplitude e and the fly-back pulse amplitude e Therefore, when, by way of example, the load current is always kept flowing through the high resistance 4a connected between the output terminal 2a and ground, the input waveform of the voltage multiplication rectifier circuit can be deprived of the ringing pulse amplitude e;, as shown in FIG. 6(B) even in the case where no current is permitted to flow through the Braun tube 2. Accordingly, even if the load currents 1,, and I, change, changes in e /e can be restrained to a very small value.

In a voltage multiplying rectification system of n stages, the ratio E,,/E,,, between the voltage-multiplied rectification output E,, and the m-th stage providing the high voltage E, becomes as the following equation by transforming equation (7):

Herein, n/m necessary for obtaining the ratio E,,/E,,, as required becomes a certain fixed value. As the numbers m and n are larger, the denominator of the second term on the right in equation (8) becomes larger with respect to the fixed value n/m, and a variation due to the fluctuation of e becomes smaller. That is, even if e changes due to a change of the load, the change in E,,/E,,, will be smaller as m and n are made larger.

Thus, E /E, can be held constant even under the fluctuation of the high voltage load, in such manner that the flyback transformer of the fifth harmonics tun- 6 ing system is employed, that the high resistance 4a is connected between any stage of the voltage multiplication rectifier circuit and the earth or another stage and that the load is always derived from the flyback trans- 5 former 1. In addition, the fine adjustment of E /El E l can be made in such way that the DC voltage E applied to the lower voltage side of the secondary winding of the fly-back transformer is changed.

In this way, the ratio E,,/E,,, between the high voltage E and the intermediate high voltage'E, E,) can be selected at an adequate value, and it is kept constant even with fluctuation of the load of the high voltage power source, so that an after-focusing type color television receiver which is very stable in color purity can be realized.

The after-focusing type color television receiver can bringa very stable color purity into realization .by making the ratio of E and E,, E constant as stated above. However, the beam current of the Braun tube 3 strikes the shadow mask 3b and thus creates secondary electrons, so that halation is likely to occur on the screen. In such a case, a voltage higher than the mask voltage E,,, is applied to the funnel portion electrode 3c, whereby the secondary electrons are absorbed by the funnel portion and the halation is prevented from occurring.

FIG. 7 is a circuit diagram showing another embodiment of the present invention which has solved the aforesaid problem. According to the embodiment, a voltage stabilizing element 6, such as a constantvoltage diode, and a resistance 7 are connected in series between the m-th stage and the (m l)-th stage of the n-ple voltage rectifier circuit 2. The output of the voltage multiplication rectifier circuit 2 at the m-th stage is applied to the shadow mask 3b, while the voltage of the juncture between the voltage stabilizing element 6 and the resistance 7 is impressed on the funnel portion electrode 3c. As a result, the funnel portion voltage E, becomes higher than the shadow mask voltage V,,, by a voltage V across the voltage stabilizing element 6.

The series circuit consisting of the voltage stabilizing element 6 and the resistor 7 may also be connected between the m-th stage and any other stage.

In order to stably hold the color purity in the circuit of FIG. 7, the ratio between E,, and E; should be maintained constant. To this end, (E E may be made constant since the ratio between E, and E is held sub stantially constant, as previously stated. The voltage difference (E E is kept substantially constant by the voltage stabilizingelement 6, so that the ratio E,,/E, is held constant after all.

When the load of the voltage multiplication rectifier circuit 2 fluctuates, the brightness of the receiver is raised by, for example, increasing the phosphor screen current 1 Then as shown in FIG. 8, the high voltages E E and E decrease. As a consequence, the load currents I; and I, increase, thereby to reduce a current 1 flowing through the voltage stabilizing element 6.

The characteristic of the voltage stabilizing element 6 is such that, as illustrated in FIG. 9, the voltage V, across the terminals of the element decreases slightly in response to the decrease of the current 1,, flowing therethrough. Therefore, in the case where the high voltage load increases and E and E,, decrease, V changes in the direction of keeping E /E, unchanged, and hence, the ratio E /E is held substantially constant.

Thus, the ratios between E;, and E,,, and between 5,, and E, can be selected at adequate values, respectively, and they are constant even with fluctuation of the load of the high voltage power source, so that an afterfocusing type color television receiver which is very stable in color purity and free from halation can be realized.

FIG. shows another embodiment of the present invention. As the voltages to be applied to the shadow mask 3b and the funnel portion 30 of the Braun tube 3, desired higher voltages are produced from the voltage of an intermediate stage M of the voltage multiplication rectifier circuit 2.

Referring to the figure,

diodes

9 and 10 are connected in series between the intermediate stage M of the n-ple voltage rectifier circuit 2 and the funnel portion 30. A capacitor 11 is connected in parallel with the

diodes

9 and 10.

On the other hand, the voltage between the primary winding 1a of the fly-back transformer l and ground is divided by capacitors l2 and 13. The divided voltage is applied through a capacitor 8 to the juncture between the

diodes

9 and 10.

The voltage of the primary side of the fly-back transformer 1 may be divided by any other impedance elements. Further, the total voltage may be applied without dividing it As a result, there can be obtained, as the output voltage of the diode 10, the voltage E; of a value with a voltage from rectification of the primary voltage of the fiy-back transformer 1 added to the output voltage of the intermediate stage M of the voltage multiplying rectifier circuit 2. In order to more fully stabilize the voltage E,, a resistor may be connected in parallel with the capacitor 11.

The output voltage of the diode 10 can be arbitrarily varied by changing the division ratio of the primary voltage of the transformer 1. Since only the funnel portion voltage L} can be varied without changing the output voltage E ofthe voltage multiplication rectifier circuit 2 (the phosphor screen voltage), the ratio E /E; is expressed by the following equation:

where V is the DC voltage between the point M and the funnel portion 30.

As is understood from equation (9), a change in V can vary E /E, more efficiently than a change in the voltage E. Even when the load of the n-ple voltage rectifier circuit 2 fluctuates. lib/E, and E1,/E,are held very stable.

In the circuit of FIG. 10, the pulse voltage to be applied to the capacitor 8 may also be obtained in such a way that the tertiary winding is provided for the flyback transformer I, to use pulses induced in the windmg.

In this case, the amplitude of the pulses can be controlled through a change in the coupling coefficient by shifting the position of the tertiary winding. Therefore, this method can also vary the ratio between E and FIG. 11 shows an example of the construction of the transformer in the case where the tertiary winding is provided for the transformer 1 as stated above. Referring to the figure, numeral 14 designates the iron core of the transformer; 15 is the primary winding; 16 is the secondary winding; and 17 is the tertiary winding. The position of the tertiary winding 17 is moved in the directions of arrows, whereby the coupling coefficients with the other windings change, and the voltage induced in the tertiary winding is also increased or decreased Further, two inductance elements are connected in series on the primary side of the fly-back transformer 1, to obtain a divided voltage from the junction point of the inductance elements. Therewith, a winding is wound on the iron core of one of the inductance elements, and a current flowing through the winding is varied, whereby the inductance of the element can be varied to change the voltage division ratio. With such a construction, the voltage V in equation (9) can be continuously changed, and E /E can be arbitrarily varied as may be needed.

FIG. 12 shows an embodiment as referred to above.

Inductance elements

18 and 19 are connected in series on the primary side of the transformer 1. On the same iron core as that of the inductance element 19, an additional winding 20 is wound. A current is supplied from a DC power source 22 through a variable resistance 21 to the winding 20. When the current is varied, the inductance of the inductance element 19 is changed. The value ofthe voltage to be applied to the junction point of the

diodes

9 and 10 can accordingly be changed.

FIG. 13 shows still another embodiment of the present invention. According to this circuit, in order to apply different voltages to the funnel portion 30 and the shadow mask 3b, a potential at one end of the voltage stabilizing element 6 is applied to the funnel potion 30, while a potential at the other end of the element 6 is applied to the shadow mask 3b. In order to make the ratios E /E" and E /E variable, there are also provided the

capacitors

12 and 13 for dividing the primary voltage of the transformer l, the

diodes

9 and 10 and the cpaacitor 11 for rectifying and smoothing the divided voltage, etc. With such circuit arrangement, the effects as described with reference to FIGS. 7 and 10 are attained.

What is claimed is:

1. A high voltage circuit for a color television receiver, comprising:

a. fly-back transformer means including a primary winding and a secondary winding for producing high voltage pulses from horizontal deflection outputs,

2. multiple stage voltage rectifier means made up of double voltage rectifier circuits formed into n stages for producing high DC voltages from the output of said transformer means,

3. A Braun tube including a shadow mask, a phos phor screen and a funnel electrode portion,

4. means to apply the output of the n-th stage of said voltage rectifier means to said phosphor screen, and means to apply the output of the m-th stage to said shadow mask, where n and m are integers, n being greater than m and greater than I, and

5. means including a voltage stabilizing element connected between an output terminal of an I-th stage, where (l 1 g n), of said voltage rectifier means and ground to stabilize the current flowing from said voltage rectifier means through said element to ground, thereby to maintain constant the voltage ratio between the phosphor screen voltage and the shadow mask voltage.

2. The high voltage circuit accordjggto clai n I wherein a tuning capacitor for taking out third higher harmonics is connected in parallel with said secondary winding of said fly-back transformer, and wherein said voltage stabilizing element is a Zener diode.

3. The high voltage circuit according to claim 1, wherein a tuning capacitor for taking out fifth higher harmonics is connected in parallel with said secondary winding of said flyback transformer, and wherein said voltage stabilizing element is a resistor having high resistance.

4. The high voltage circuit according to claim 1, fur ther comprising means to apply the output voltage of said m-th stage of said voltage rectifier means to said funnel electrode portion of said Braun tube.

5. The high voltage circuit according to claim 1, wherein a further voltage stabilizing element and a resistance element are connected in series between an output terminal of said m-th stage of said voltage rectifier means and that of the (m l)-th or later stage, and a voltage across said stabilizing element is applied between said shadow mask and said funnel electrode portion.

6. The high voltage circuit according to claim 1, wherein a variable DC power source is connected between one end of a secondary winding of said fly-back transformer means and ground, so that the supply voltage of said power source can be varied to thereby perform the fine adjustment of the ratio E /E, between the voltage E applied to said phosphor screen of said Braun tube and the voltage E applied to said shadow mask.

7. The high voltage circuit according to claim 6, wherein a tuning capacitor for taking out third higher harmonics is connected in parallel with said secondary winding of said flyback transformer, and wherein said voltage stabilizing element is a Zener diode.

8. The high voltage circuit according to claim 7, further comprising means to apply the output voltage of said m-th stage of said voltage rectifier means to said funnel electrbde portion of said Eraun tube.

9. The high voltage circuit according to claim 6, wherein a tuning capacitor for taking out fifth higher harmonics is connected in parallel with said secondary winding of said flyback transformer, and wherein said voltage stabilizing element is a resistor having high resistance 10. The high voltage circuit according to claim 9 further comprising means to apply the output voltage of said mth stage of said voltage rectifier means to said funnel electrode portion of said Braun tube.

11. The high voltage circuit according to claim 10, wherein a further voltage stabilizing element and a resistance element are connected in series between an output terminal of said m-th stage of said voltage rectifier means and that of the (m l)-th or later stage, and a voltage across said stabilizing element is applied between said shadow mask and said funnel electrode portion.

12. In a high voltage circuit for a color television receiver comprising: fly-back transformer means including a primary winding for receiving horizontal deflection outputs. and a secondary winding for producing high voltage output pulses, multiple stage voltage rectifier means made up of double voltage rectifier circuits formedinto n stages for producing high DC voltages from the output of said transformer means, a Braun tube including a shadow mask, a phosphor screen and a funnel electrode portion, means to apply the output of the n-th stage of said voltage rectifier means to said phosphor screen, and means to apply the output of the m-th stage to said shadow mask, where n and m are integers, n is greater than 1 and greater than m, the improvement which comprises a resistor having high resistance connected between an output terminal of the l-th stage (1 I n) of said voltage rectifier means and ground to enable a steady current to flow from said voltage rectifier means through the resistor to ground, means to divide the voltage of the primary winding of said fly-back transformer means, rectifier means to rectify the divided voltage, adder means to add the output voltage of said m-th stage of said voltage rectifier means and an output voltage of the rectifier means, and means to apply the output voltage of said adder means to said funnel electrode portion of said Braun tube whereby to maintain constant the voltage ratio E1,/E,,, between the phosphor screen voltage E and the shadow mask voltage E, and the voltage ratio E /E; between the phosphor voltage E and the voltage E; applied to the funnel portion of the tube.

13. The high voltage circuit according to claim 12, wherein said voltage dividing means comprises first and second capacitance elements connected in series between one end of said primary winding of said fly-back transformer and ground, said rectifier means compris-.

ing first and second rectifiers connected in series between said stage output terminal and said funnel electrode and a third capacitive element connected between the point of connection of said first and second capacitive elements and the point of connection of said first and second rectifiers.

14. The high voltage circuit according to claim 12, wherein said voltage dividing means comprises first and second inductance elements connected in series between one end of said primary winding of said fly-back transformer and ground, a winding wound on a core of one of said inductance elements, and means to supply a variable current to the last-mentioned winding, whereby a voltage provided from a juncture between said first and second inductance elements can be changed by varying the current of said winding.

15. The high voltage circuit according to claim 1, wherein said transformer means further comprises a third winding movably wound on a core on which said primary and secondary windings are wound, rectifier means to rectify the voltage induced in said tertiary winding, adder means to add the output voltage of-said m-th' stage of said voltage rectifier means and the output voltage of the rectifier means, and means to apply the output voltage of the adder means to said funnel electrode portion of said Braun tube, whereby said tertiary winding may be moved to thereby change its electromagnetic coupling coefficients with the other windings, so as to vary the induced voltage in said tertiary winding.

16. A high voltage circuit for a color television receiver, comprising:

1. fly-back transformer means for producing high voltage pulses from horizontal deflection outputs,

2. multiple stage voltage rectifier means made up of double voltage rectifier circuits formed into n 5. means including a voltage stabilizing element connected between output terminals of any different stages of said voltage rectifier means to enable a steady current to flow through said element.

17. The high voltage circuit according to claim 16, wherein said voltage stabilizing element is a resistor of high resistance.

Claims

1. A high voltage circuit for a color television receiver, comprising: a. fly-back transformer means including a primary winding and a secondary winding for producing high voltage pulses from horizontal deflection outputs, 2. multiple stage voltage rectifier means made up of double voltage rectifier circuits formed into n stages for producing high DC voltages from the output of said transformer means,

2. Th high voltage circuit according to claim 1, wherein a tuning capacitor for taking out third higher harmonics is connected in parallel with said secondary winding of said fly-back transformer, and wherein said voltage stabilizing element is a Zener diode.

3. a Braun tube including a shadow mask, a phosphor screen and a funnel electrode portion,

3. A Braun tube including a shadow mask, a phosphor screen and a funnel electrode portion, 4. means to apply the output of the n-th stage of said voltage rectifier means to said phosphor screen, and means to apply the output of the m-th stage to said shadow mask, where n and m are integers, n being greater than m and greater than 1, and 5. means including a voltage stabilizing element connected between an output terminal of an l-th stage, where (1 < l < OR = n), of said voltage rectifier means and ground to stabilize the current flowing from said voltage rectifier means through said element to ground, thereby to maintain constant the voltage ratio between the phosphor screen voltage and the shadow mask voltage.

4. means to apply the output of the n-th stage of said voltage rectifier means to said phosphor screen, and means to apply the output of the m-th stage to said shadow mask, where n and m are integers, n being greater than m and greater than 1, and

4. means to apply the output of the n-th stage of said voltage rectifier means to said phosphor screen, and means to apply the output of the m-th stage to said shadow mask, n being greater than m, and

4. The high voltage circuit according to claim 1, further comprising means to apply the output voltage of said m-th stage of said voltage rectifier means to said funnel electrode portion of said Braun tube.

5. The high voltage circuit according to claim 1, wherein a further voltage stabilizing element and a resistance element are connected in series between an output terminal of said m-th stage of said voltage rectifier means and that of the (m + 1)-th or later stage, and a voltage across said stabilizing element is applied between said shadow mask and said funnel electrode portion.

5. means including a voltage stabilizing element connected between an output terminal of an l-th stage, where (1 < l < or = n), of said voltage rectifier means and ground to stabilize the current flowing from said voltage rectifier means through said element to ground, thereby to maintain constant the voltage ratio between the phosphor screen voltage and the shadow mask voltage.

5. means including a voltage stabilizing element connected between output terminals of any different stages of said voltage rectifier means to enable a steady current to flow through said element.

6. The high voltage circuit according to claim 1, wherein a variable DC power source is connected between one end of a secondary winding of said fly-back transformer means and ground, so that the supply voltage of said power source can be varied to thereby perform the fine adjustment of the ratio Eb/Em between the voltage Eb applied to said phosphor screen of said Braun tube and the voltage Em applied to said shadow mask.

8. The high voltage circuit according to claim 7, further comprising means to apply the output voltage of said mth stage of said voltage rectifier means to said funnel electrode portion of said Braun tube.

9. The high voltage circuit according to claim 6, wherein a tuning capacitor for taking out fifth higher harmonics is connected in parallel with said secondary winding of said flyback transformer, and wherein said voltage stabilizing element is a resistor having high resistance.

10. The high voltage circuit according to claim 9 further comprising means to apply the output voltage of saiD mth stage of said voltage rectifier means to said funnel electrode portion of said Braun tube.

11. The high voltage circuit according to claim 10, wherein a further voltage stabilizing element and a resistance element are connected in series between an output terminal of said m-th stage of said voltage rectifier means and that of the (m + 1)-th or later stage, and a voltage across said stabilizing element is applied between said shadow mask and said funnel electrode portion.

12. In a high voltage circuit for a color television receiver comprising: fly-back transformer means including a primary winding for receiving horizontal deflection outputs, and a secondary winding for producing high voltage output pulses, multiple stage voltage rectifier means made up of double voltage rectifier circuits formed into n stages for producing high DC voltages from the output of said transformer means, a Braun tube including a shadow mask, a phosphor screen and a funnel electrode portion, means to apply the output of the n-th stage of said voltage rectifier means to said phosphor screen, and means to apply the output of the m-th stage to said shadow mask, where n and m are integers, n is greater than 1 and greater than m, the improvement which comprises a resistor having high resistance connected between an output terminal of the l -th stage (1 < l < or = n) of said voltage rectifier means and ground to enable a steady current to flow from said voltage rectifier means through the resistor to ground, means to divide the voltage of the primary winding of said fly-back transformer means, rectifier means to rectify the divided voltage, adder means to add the output voltage of said m-th stage of said voltage rectifier means and an output voltage of the rectifier means, and means to apply the output voltage of said adder means to said funnel electrode portion of said Braun tube whereby to maintain constant the voltage ratio Eb/Em between the phosphor screen voltage Eb and the shadow mask voltage Em and the voltage ratio Eb/Ef between the phosphor voltage Eb and the voltage Ef applied to the funnel portion of the tube.

13. The high voltage circuit according to claim 12, wherein said voltage dividing means comprises first and second capacitance elements connected in series between one end of said primary winding of said fly-back transformer and ground, said rectifier means comprising first and second rectifiers connected in series between said l stage output terminal and said funnel electrode and a third capacitive element connected between the point of connection of said first and second capacitive elements and the point of connection of said first and second rectifiers.

15. The high voltage circuit according to claim 1, wherein said transformer means further comprises a third winding movably wound on a core on which said primary and secondary windings are wound, rectifier means to rectify the voltage induced in said tertiary winding, adder means to add the output voltage of said m-th stage of said voltage rectifier means and the output voltage of the rectifier means, and means to apply the output voltage of the adder means to said funnel electrode portion of said Braun tube, whereby said tertiary winding may be moved to thereby change its electromagnetic coupling coefficients with the Other windings, so as to vary the induced voltage in said tertiary winding.

16. A high voltage circuit for a color television receiver, comprising: