JPS6340480A - Converging and deflecting voltage supply circuit - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Field of industrial application B. Overview of the invention C. Prior art D. Problem to be solved by the invention E. Means for solving the problem F. Figure 2) G-2 Modification Example (Figures 2 and 3) H Effect of the Invention A Industrial Application Field The present invention is applicable to, for example, an electrostatic focusing/deflecting electrode in an electrostatic focusing/electrostatic deflection type image pickup tube. , relates to a focusing/deflection voltage supply circuit that supplies a focusing/deflection voltage in the form of a sawtooth voltage.

B. Summary of the Invention The present invention provides, for example, an electrostatic focusing/deflecting device having an electrostatic focusing/deflecting electrode formed such that the focusing electrode also serves as a deflecting electrode.
In the focusing/deflection voltage supply circuit that supplies the focusing/deflection voltage in the form of a sawtooth wave voltage to the electrostatic deflection type image pickup tube, a focusing voltage adjustment section that generates a variable focusing control voltage is provided, and the electrostatic focusing/deflecting electrode For the sawtooth wave voltage that is supplied as a focusing/deflecting voltage to the DC voltage component and whose DC voltage component is the focusing voltage,
A feedback DC level that compares the DC voltage level with the level of the focusing control voltage from the focusing voltage regulator and changes the DC voltage level of the sawtooth voltage in accordance with a control signal formed based on the comparison result. By performing control, the focusing voltage for the electrostatic focusing deflection electrode can be reliably and stably adjusted with a relatively simple configuration by changing the focusing control voltage from the focusing voltage adjustment section. It has been made possible to do so.

C. Conventional technology In an electrostatic focusing/electrostatic deflection type image pickup tube, one of the electrode groups for electrostatic focusing of the electron beam also serves as a deflection electrode for electrostatic deflection of the electron beam. It is said that Then, on this dual-purpose electrostatic electrode, a horizontal deflection voltage that is a sawtooth wave voltage with a horizontal period and a vertical deflection voltage that is a sawtooth wave voltage with a vertical period are superimposed on a focused voltage that is a predetermined DC voltage. A focusing/deflecting voltage obtained in this manner is supplied, and the focusing/deflecting voltage usually has a charging/discharging portion including a combination of a switching element and a capacitor that are switched in a horizontal period or a vertical period. It is formed by a sawtooth wave voltage forming circuit.

In such an electrostatic focusing/electrostatic deflection type image pickup tube, when performing focus adjustment to adjust the focusing state of the electron beam at the target, the horizontal deflection voltage and the vertical deflection voltage, which are sawtooth wave voltages, are used. It is required that the level of the DC voltage component of the focusing voltage, i.e. the focusing/deflecting voltage, be changed without changing the amplitude of the focusing voltage, i.e. the focusing/deflecting voltage, in particular the sawtooth wave forming the focusing/deflecting voltage. A DC level shift circuit is provided at the output end of the voltage forming circuit, and the operation of the DC level shift circuit causes the DC voltage level of the focusing/deflection voltage formed by the sawtooth wave voltage forming circuit to change the sawtooth wave amplitude. You can be forced to change by not letting it happen.

D. Problems to be Solved by the Invention - Necessary for focus adjustment as described above.
Conventional circuits for producing changes in the DC voltage level of the focusing/deflection voltage obtained from the sawtooth voltage forming circuit are supposed to perform open loop control over the DC level of the focusing/deflection voltage.

For example, the output end of the sawtooth voltage forming circuit is connected to a DC level shift circuit, and the current flowing through the DC level shift circuit is controlled, for example, according to a focusing control signal, so that the output end of the sawtooth voltage forming circuit is connected to the DC level shift circuit. By changing the DC voltage level of the focusing/deflecting voltage, a DC level change of the focusing/deflecting voltage is obtained.

However, in conventionally proposed focusing/deflection voltage supply circuits that perform open-loop control of the DC voltage level, for example, the characteristics of each active element such as each transistor constituting the DC level shift circuit section are It is easy to be affected by variations in characteristics due to unevenness or temperature changes, and various correction units and compensation units are required to stably maintain a properly adjusted focus state. Therefore, there is a problem that the configuration becomes extremely complicated, and furthermore, it is difficult to sufficiently stabilize the focus state.

In view of these points, the present invention provides an electrostatic focusing east deflection electrode such as a dual-purpose electrostatic electrode in an electrostatic focusing/electrostatic deflection type image pickup tube.
In supplying the focusing/deflection voltage as a sawtooth wave voltage having a predetermined DC voltage component, the direct current of the focusing/deflection voltage as the focusing voltage to the electrostatic focusing/deflecting electrode can be supplied based on a relatively simple configuration. The purpose of this invention is to propose a focusing/deflection voltage supply circuit that can perform level adjustment of voltage components reliably and stably.

E. Means for Solving the Problems In order to achieve the above-mentioned object, the focusing/deflection voltage supply circuit according to the present invention includes a sawtooth wave voltage generator that generates a sawtooth wave voltage having a predetermined DC voltage component. and controlling the DC voltage level of the sawtooth voltage obtained from the sawtooth voltage generator,
Focuses sawtooth wave voltage with controlled DC voltage level.
a DC level shift unit that supplies the electrostatic focusing deflection electrode as a deflection voltage; a DC level detection unit that detects the DC voltage level of the sawtooth wave voltage obtained from the DC level shift unit;
a focusing voltage adjustment section that generates a variable focusing control voltage; a level control section that compares the DC voltage level detected by the DC level detection section with the level of the focusing control voltage and forms a control signal based on the comparison result; The level control section supplies the control signal obtained thereby to the DC level shift section, and causes the DC level shift section to adjust the DC voltage level of the sawtooth wave voltage obtained from the sawtooth voltage generation section. It is assumed that the operation is changed according to the control signal.

F Effect In the focusing/deflection voltage supply circuit according to the present invention configured as described above, the DC voltage level of the sawtooth wave voltage obtained from the sawtooth voltage generator is detected by the DC level detector, and The level control section compares the level of the focus control voltage from the focus voltage adjustment section, and the DC level shift section performs control according to a control signal obtained from the level control section based on the result of the comparison made therein. Therefore, feedback control is performed on the DC voltage level of the sawtooth wave voltage obtained from the sawtooth voltage generation section, and as a result, the DC voltage level is supplied from the DC level shift section to the electrostatic focusing/deflection electrode as a focusing/deflection voltage. The DC voltage component of the sawtooth voltage, ie the level of the focusing voltage, will be adjusted to follow the level of the focusing control voltage from the focusing voltage regulator.

In this way, the level of the DC voltage component in the sawtooth wave voltage, which is the focusing/deflection voltage, is adjusted according to the level of the focusing control voltage from the focusing voltage adjustment section under feedback control. As a result, the level adjustment of the focusing voltage for the electrostatic focusing deflection electrode can be performed reliably and stably with a relatively simple configuration.

G Example G-1 Overall configuration and operation (Figures 1 and 2) Figure 1 shows the following:
1 shows an example of a focusing/deflection voltage supply circuit according to the present invention. In this example, a focusing/deflection voltage is supplied to an electrostatic focusing/deflection electrode of an electrostatic focusing/electrostatic deflection type image pickup tube.

In the example shown in FIG. 1, a horizontal focusing/deflection voltage generating section 10 and a vertical focusing/deflecting voltage generating section 11 are provided, respectively. The horizontal focusing/deflection voltage generating section IO is a second
Power supply voltages Vha and Vhb, respectively, as shown in Figure A.
The voltage Vho between (Vha>Vhb) is used as a DC voltage component, and the sawtooth wave voltages sh and sh' with horizontal period Th and opposite polarities are generated. As shown in FIG. 2B, the voltage Vvo between the power supply voltages Vva and Vvb (Vva>Vvb) is used as a DC voltage component, and the polarities are opposite to each other.
Sawtooth voltages Sv and s vl of vertical period Tv are generated.

The sawtooth wave voltages sh and sh' obtained from the horizontal focusing/deflection voltage generating section 10 are applied to the DC level shifting section 12, respectively.
and 13 to output terminals 14 and 15. The DC voltage levels of these sawtooth wave voltages sh and sh' derived to the output terminals 14 and 15 are detected by a DC level detection unit I6 provided on the output side of the DC level shift units 12 and 13. The DC level detection unit 16 includes resistors 17 and 18 whose one ends are connected to the output ends of the DC level shift units 12 and 13, respectively, and whose one end is commonly connected to the other ends of both of the resistors 16 and 17. and one capacitor whose other end is grounded, and at the connection point ph between the resistors 17 and 18 and the capacitor 19,
A voltage Vhp corresponding to the detected DC voltage level is obtained.

On the other hand, the sawtooth wave voltages Sv and Sv' obtained from the vertical focusing/deflection voltage generating section 11 are led out to output terminals 22 and 23 via DC level shift sections 20 and 21, respectively. The DC voltage levels of these sawtooth wave voltages Sv and Sv'' derived to the output terminals 22 and 23 are detected by the DC level detection unit 24 provided on the output side of the DC level shift units 20 and 21. The level detection section 24 has resistors 25 and 26 whose one ends are connected to the output terminals of the DC level shift sections 20 and 21, respectively, and whose one end is commonly connected to the other ends of both of these resistors 25 and 26. and a capacitor 27 whose other end is grounded, and a connection point Pv between the resistors 25 and 26 and the capacitor 27
Then, a voltage Vvp corresponding to the detected DC voltage level is obtained.

Furthermore, in this example, a focus voltage adjustment section 32 consisting of a variable resistor 3o and a buffer 31 is provided. DC voltages Vcc and Vf f (Vcc>Vff) are applied to both ends of the variable resistor 30, respectively, and a voltage Vr between the DC voltage Vcc and Vff is applied to the variable terminal. Obtained at different levels depending on location.

Then, the voltage Vhp obtained at the connection point ph in the DC level detection section 16 is supplied to one input terminal of the comparison amplification section 40, and the voltage obtained at the variable terminal of the variable resistor 30 in the focused voltage adjustment section 32. Vr is supplied to the other input terminal of the comparison amplification section 40 via the buffer 31 and further via the resistor 41. As a result, an output signal corresponding to the level difference between the voltage Vhp and the voltage Vr is obtained at the output terminal of the comparison amplification section 40, and this output signal is passed through a low-pass filter (LPF) 42 to provide a control signal. c.
The signal h is supplied to each control end of the DC level shift units 12 and 13. In the DC level shifters 12 and 13, the DC voltage levels of the sawtooth wave voltages sh and sh' obtained from the horizontal focusing/deflection voltage generator 10 are adjusted according to the control signal ch, that is, the voltage Vhp and the voltage Vr. As a result, the DC level shifters 12 and 13 output terminals 14 and 13, respectively.
The DC voltage levels of the sawtooth wave voltages sh and sh sent to the variable resistor 30 in the focusing voltage adjustment section 32
The voltage V set at and sent out through the buffer 31
r.

In this way, the DC voltage level of the sawtooth wave voltages Sh and sh'' sent from the horizontal focusing/deflection voltage generator 10 to the output j terminals 14 and 15 via the DC level shifters 12 and 13 is adjusted. A feed hack control u-loop is formed to perform control according to the output of the focusing voltage adjustment section 32, and the DC voltage levels of the sawtooth wave voltages sh and sh derived to the output terminals 14 and 15 are adjusted accordingly. is stabilized by being adjusted according to the output of the focusing voltage adjusting section 32 under feedback control.

At the same time, the voltage Vvp obtained at the connection point pv in the DC level detection section 24 is supplied to one input end of the comparison amplification section 43, and the focused voltage adjustment section 32
The voltage Vr obtained at the variable terminal of the variable resistor 30 at
is supplied to the other input terminal of the comparison amplification section 43 via the buffer 31 and further via the resistor 44. As a result, an output signal corresponding to the level difference between the voltage VVI) and the voltage Vr is obtained at the output end of the comparison amplification section 43.
This output signal is passed through a low-pass filter (LPF) 45 as a control signal Cv to the DC level shift units 20 and 2.
1 to each control end. As a result, in the DC level shift units 20 and 21, the sawtooth wave voltages Sv and Sv'' obtained from the vertical focusing/deflection voltage generating unit 11 are
The DC voltage level of is changed according to the control signal Cv, that is, according to the level difference between the voltage Vvp and the voltage Vr, and as a result, the output terminals 22 and 23 are output from the DC level shifters 20 and 21, respectively. The DC voltage levels of the sawtooth wave voltages Sv and s vl sent out are set by the variable resistor 30 in the focusing voltage adjustment section 32 and follow the voltage Vr sent out through the buffer 31.

In this way, the DC voltage level of the sawtooth wave voltages S and Sv' sent from the vertical focusing/deflection voltage generator 11 to the output terminals 22 and 23 via the DC level shifters 20 and 21 is A feedback control loop is formed that performs control according to the output of the focusing voltage adjustment section 32, and the DC voltage levels of the sawtooth wave voltages Sv and Sv'' derived to the output terminals 22 and 23 are as follows. Under feedbank control, the voltage is stabilized and adjusted according to the output of the focusing voltage adjusting section 32.

Based on the configuration and operation as described above, the sawtooth wave voltages sh and Sh'' obtained at the output terminals 14 and 15, and the sawtooth wave voltages Sv and 3 obtained at the output terminals 22 and 23.
vl is supplied as a focusing/deflection voltage to the horizontal and vertical electrostatic focusing/deflecting electrodes of the electrostatic focusing/deflecting image pickup tube, respectively. At that time, the DC voltage components of the sawtooth voltages sh and sh' and Sv and Sv'' are electrostatically focused and
This is the focusing voltage for the horizontal and vertical electrostatic focusing deflection electrodes of an electrostatic deflection type image pickup tube.

In this way, by supplying the focusing/deflection voltage according to this example, the sawtooth wave voltages sh and Sh', the sawtooth wave voltages Sv and Based on Sv', electrostatic focusing and deflection of the electron beam are performed.

When focus adjustment is performed on the electrostatic focusing/electrostatic deflection type image pickup tube, the movable terminal of the variable resistor 3o forming the focusing voltage adjusting section 32 is controlled to move, and the voltage Vr obtained therefrom changes. DC voltage levels of the sawtooth wave voltages sh and sh' obtained from the horizontal focusing/deflection voltage generator 10 and sent to the output terminals 14 and 15 via the DC level shifters 12 and 13, The DC voltage levels of the sawtooth wave voltages Sv and Sv' obtained from the vertical focusing/deflection voltage generator 11 and sent to the output terminals 22 and 23 via the DC level shifters 20 and 21 are respectively the DC level. Shift parts 12 and 13
, and the DC level shifters 20 and 21, the voltage Vr is changed to follow the change in the voltage Vr. Therefore,
DC voltage components of the sawtooth wave voltages sh and sh' and the sawtooth wave voltages Sv and Sv' supplied to the horizontal and vertical electrostatic focusing and deflection electrodes of the electrostatic focusing/electrostatic deflection type image pickup tube, i.e. , the focusing voltage is changed, and the focusing voltage for the horizontal and vertical electrostatic focusing/deflecting electrodes of the electrostatic focusing/electrostatic deflection type image pickup tube is adjusted according to the control of the variable resistor 30 forming the focusing voltage adjusting section 32. will be done.

In this way, the focusing voltages for the horizontal and vertical electrostatic focusing/deflection electrodes of the electrostatic focusing/electrostatic deflection type image pickup tube can be adjusted with a relatively simple configuration and by controlling the focusing voltage adjusting section 32. , can be performed stably under Freud-back control.

G-2 Modified Example (Figures 2 and 3) DC level detection section 1 in the example shown in Figure 1 above
6, as shown in FIG. 3, a switch 50 is inserted between the connection point Ph and the capacitor 19, and this switch 5
0 and the capacitor 19, the voltage Vhp' obtained at the connection point ph" between the capacitor 19 and the comparison amplifier 40
may be supplied to one input terminal of the . In such a case, the switch 50 is connected to the horizontal focusing/deflection voltage generator 1 as shown in FIG. 2A, which is supplied from the terminal 51.
It is controlled by a pulse signal Sp synchronized with the central part of the level slope of each of the sawtooth wave voltages sh and sh' obtained from 0, and is turned on only when the pulse signal Sp arrives,
It is turned off during other periods.

In this case, the voltage vhp' obtained at the connection point ph' is
The sawtooth wave voltages sh and sh according to the level of the central part of the level slope part of the sawtooth wave voltages sh and sh', respectively.
' is not affected by level fluctuations in other parts, etc., and the DC voltage level of the sawtooth wave voltages sh and sh'' is
It is considered to be more stable.

Although not shown, a switch is similarly inserted between the connection point Pv and the capacitor 27 in the DC level detection section 24 in the example shown in FIG. It is turned on only when a pulse signal synchronized with the central part of the level slope of each of the sawtooth wave voltages Sv and Sv'' obtained from the focusing/deflection voltage generator 11 arrives, and is turned off during other periods. In addition, the voltage obtained at the connection point between the switch and the capacitor 27 may be supplied to one input terminal of the comparison amplifier section 43 instead of the voltage V V I). Even in such a case, the voltage obtained at the connection point between the switch and the capacitor 27 will more stably correspond to the DC voltage level of the sawtooth wave voltages Sv and Sv'.

Effects of the Invention H As is clear from the above explanation, the focusing/deflection voltage supply circuit according to the present invention can be applied to an electrostatic focusing/deflecting electrode such as a dual-purpose electrostatic electrode in an electrostatic focusing/electrostatic deflection type image pickup tube. In supplying a sawtooth wave voltage having a predetermined DC voltage component as a focusing/deflection voltage using the DC voltage component as a focusing voltage, for example, by controlling a focusing voltage adjustment section that generates a variable control voltage. The DC voltage component of the sawtooth wave voltage applied to the electrostatic focusing deflection electrode, that is, the level of the focusing voltage can be stably and reliably adjusted with a relatively simple configuration under feed hack control. Therefore, the focusing/deflection voltage supply circuit according to the present invention provides an electrostatic focusing/deflection voltage supply circuit.
When applied to an electrostatic deflection type image pickup tube, it is possible to improve the stability of focus adjustment with a relatively simple configuration. It is suitable for use in a three-tube color imaging device that uses three electrostatic focusing/electrostatic deflection type imaging tubes for signal formation.

[Brief explanation of the drawing]

FIG. 1 is a circuit connection diagram showing an example of the focusing/deflection voltage supply circuit according to the present invention, and FIGS. 2A and 2B serve to explain the operation of the example shown in FIG. 1 and the modified example shown in FIG. 3. FIG. 3 is a circuit connection diagram showing essential parts of a modification to the example shown in FIG. 1. In the figure, 10 is a horizontal focusing/deflection voltage generation section, 11 is a vertical focusing/deflection voltage generation section, and 12. 13. 20 and 21 are DC level shift units, 14, 15, 22 and 23 are output terminals, 16 and 24 are DC level detection units, 30 is a variable resistor, 32 is a focusing voltage adjustment unit, 40 and 43 are comparison amplifier units, 42 and 45 are low pass filters.

Claims (1)

[Scope of Claims] A sawtooth wave voltage generating section that generates a sawtooth wave voltage having a predetermined DC voltage component, and controlling the DC voltage level of the sawtooth wave voltage obtained from the sawtooth wave voltage generating section. a DC level shift section that supplies a sawtooth wave voltage whose DC voltage level is controlled as a focusing/deflection voltage to the electrostatic focusing/deflection electrode; and a DC voltage level of the sawtooth wave voltage obtained from the DC level shift section. a DC level detection unit that detects the voltage, a focusing voltage adjustment unit that generates a variable focusing control voltage, and comparing the DC voltage level detected by the DC level detection unit with the level of the focusing control voltage, and A control signal formed based on the comparison result is supplied to the DC level shift section, and the DC voltage level of the sawtooth wave voltage obtained from the sawtooth voltage generation section is applied to the control signal. A focusing/deflection voltage supply circuit comprising: a level control unit that performs a changing operation according to the level control unit;