JPS5843952B2 - Convergence device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an active convergence device having a corner convergence correction function, and provides a convergence device with a smooth correction operation for high frequency components and low power consumption.

Recently, many types of displays using color picture tubes have been developed, and the convergence performance of color picture tubes is being used for high-definition, which has a high resolution and a large display density by reducing the dot pitch and increasing the number of scanning lines. has come to be strictly required.

Sometimes, adding a corner convergence adjustment function becomes an essential element, and the shift from convergence devices with so-called passive circuit configurations to convergence devices with active circuit configurations that include corner correction has become an important issue. There is.

Conventional convergence coils have a horizontal winding for passing current in the horizontal scanning period and a vertical winding for passing current in the vertical scanning period. An active method was used in which the output current was passed through an amplifier, but it was not effective in terms of performance and cost, such as problems caused by coupling between both windings and the need for two sets of output amplifiers, one horizontal and one vertical. It wasn't enough.

Therefore, recently, a so-called single winding method has been used in which the horizontal winding and vertical winding are not separated, and a current that is a combination of the horizontal period and vertical period waveforms is passed through one winding. A convergence magnetic field is obtained.

Furthermore, in order to perform static convergence electrically, there are many models in which the DC component is passed through a single winding for adjustment.

FIG. 1 shows a conventional basic active type convergence device.

In color picture tubes with a 3-electronic reading system, the electron gun is generally arranged in a delta arrangement or in-line arrangement, and three or two convergence coils are installed, but the explanation uses a single output amplifier. do.

In FIG. 1, the synchronous pulse input terminal 1 has a deflection circuit 2.
A pulse is applied to bring the output current into phase with the video signal waveform.

Generally, a composite synchronization signal is added as this pulse, but separate horizontal and vertical drive pulses may also be added.

The deflection current generated by the deflection circuit 2 flows through the horizontal deflection coil 3 and the vertical deflection coil 4.

The convergence circuit described below generates a convergence magnetic field φC that is supplied to the convergence coil 9 with the desired correction Tlt flow synchronized with the deflection current.

The waveform generating circuit 6 generates horizontal and vertical periodic parabolic waves, sawtooth wave voltages, etc. in synchronization with the retrace pulse generated by the deflection circuit 2, and couples them to the output amplifier 8 via the adder γ.

As will be explained later, in order to align the phase of the horizontally periodic parabolic waveform, the phase advance circuit 5 advances the horizontal pulse by ΔTo to completely convert the horizontal parabolic current (i.e., the convergence magnetic field φC) into the deflection current. I am making it happen.

For the vertical period, the influence of the retrace period is ignored and the time is usually not advanced.

The waveform for corner convergence is modulated waveform generation circuit 1
0 and applied to the adder 7 via the time division circuit 11.

Figure 3 shows an example of the correction wave voltage for corner convergence. This is the convergence current of the output of the time division circuit 11.

In the upper half of the screen, the convergence correction amount occurs with opposite polarity on the left and right sides, and furthermore, as shown in Figure A, at the beginning of the vertical period, the current in the horizontal period has a very large frequency component. I understand.

On the other hand, FIG. 4 shows a relational diagram of waveform phases for obtaining a horizontal parabolic current (see FIG. 4).

4A shows a video signal, FIG. 4B shows a deflection current of the horizontal deflection coil 3 synchronized with the video signal, and FIG. 4 shows a pulse synchronized with the return H pulse.

The waveform obtained by the integrating circuit from the above-mentioned three pulses in Figure 4 synchronized with the retrace pulse is often delayed in phase as shown in the waveform shown in Figure 4, and the current on the left and right sides of the screen is +1.1.
2 are different in size.

Therefore, as shown in Figure 4, the horizontal pulse input to the integrator circuit is advanced by △To in advance in order to match the phase of the final current obtained with the deflection current as shown in Figure 4. be.

The above-mentioned proposal for phase advancement is also shown in, for example, Japanese Patent Application No. 7943/1983 filed by the same applicant (Japanese Patent Application No. 13636/1982), and is a useful means for achieving high definition. be.

Further, in the conventional example shown in FIG. 1, the convergence current i.

The DC level is also variable, and corrections after static adjustment using a permanent magnet attached to the neck are performed using a circuit while looking at the screen.

As mentioned above, the convergence device shown in Figure 1 needs to have considerable frequency characteristics, and
Dynamic range is required to move up to C level.

In general, the convergence coil 9 has an inductance Lc, and the higher the frequency of the correction current, the larger the generated voltage becomes. In particular, when the correction waveform as shown in FIG. 3A is obtained, the voltage becomes even larger.

Therefore, in the single winding active system as shown in Figure 1,
An amplifier with very good frequency characteristics and good stability is required, and of course it requires a large power consumption and ample margin, which has many disadvantages in terms of temperature stability and cost.

An easy way to reduce power consumption is to lower the power supply voltage of the amplifier and slightly worsen the frequency characteristics.
The idea is to make the waveform of the output current narrow, but if you do this simply, as shown in Figure 5, the output current △1 for corner convergence will be Since there is a delay as shown in Figure 5, the convergence current in Figure 5 (B), which is in phase with the video signal (Figure 5 (A)), actually has the characteristics shown in Figure 5 (Figure 5), and is shown on the left side of the screen. The disadvantage is that the convergence of
Ru.

The present invention solves the drawbacks of the conventional configuration described above, and is a convergence device characterized in that the phase of the output voltage waveform of the modulation waveform generating circuit is adjusted by a predetermined amount further than the deflection current phase.

An embodiment of the present invention will be described below based on the drawings.

In Fig. 2, the device whose operation is basically the same as the conventional example is shown in Fig. 1.
The same reference numerals as in the figure are used.

The feature of this embodiment is that in the waveform generator of the convergence circuit, the waveform phase in the modulated waveform generation circuit 10 for corner convergence is further advanced by ΔT1 by the second phase advance circuit 14, and the corner convergence correction current is This improves the superposition characteristics of

FIG. 6 shows the waveform diagram.

Figure 6 shows the corner convergence correction voltage signal △V(
Figure 6b) is the original convergence current waveform (61st
The voltage waveform is advanced by △T1 from the phase of aa), and the corner correction current caused by △■ is △i (6th
As shown in Figure C), there is a slight delay due to the coil characteristics and the frequency characteristics of the amplifier, resulting in an optimal phase relationship for screen scanning.

An important point in the configuration of the present invention is that the delay and distortion of the correction magnetic field ΔφC of high frequency components necessary for corner correction are determined so as to be practically satisfied by the apparent advance time ΔT1.

In this embodiment, another winding 13 is further provided and used as a static coil, so that the convergence current i is generated by the interaction of the two windings.

For magnetic field φ. The higher the frequency component, the more the delay occurs.

In order to reduce this delay, the separate static winding 13 should not have a large impedance, and in order to minimize the distortion of the waveform due to large inductance, the impedance should be less than 10 times that of the convergence coil 9. This is desirable.

Furthermore, the inductance of the convergence coil 9 is selected to be as low as possible, and the frequency characteristics of the amplifier 8 are made as good as possible.
mH was selected to form the output circuit, but △T1 is △T
o, and performance without any practical problems was obtained.

Note that the above-mentioned phase advance circuit 5 has a configuration in which two stages of monostable multi-bi breaks can be obtained in series, so that an arbitrary time can be set.

In the above embodiment, sufficient corner convergence adjustment can be made even if the power supply voltage of the amplifier 8 is lowered, and conventional single winding convergence devices normally consume about 30 to 40 W of power. In the above embodiment, the power can be set to 20 W and L3 below, and since the separate winding 13 through which direct current flows is provided independently, the stability of the dynamic current of the convergence coil 9 is good, and the misconvergence can be reduced to 20 inches. We were able to achieve an accuracy of 0.35g1z or less using a color picture tube.

Furthermore, in the corner convergence adjustment, it was confirmed that the correction movement amounts on the horizontal left and right sides are almost the same on the screen.

In each of the above embodiments, the horizontal pulse to the phase advance circuit 5 is extracted from the deflection retrace pulse, but it is clear that the convergence waveform may be created using a direct synchronization signal.

In that case, although the phase advance time ΔTo becomes a little smaller, it is sufficiently effective in terms of performance.

In general, it is more natural to use a retrace pulse in order for the convergence device to work even when there is no signal.

As is clear from the above embodiments, the present invention advances the phase of the output of a waveform generation circuit that forms a convergence waveform from a pulse synchronized with a synchronization signal or a retrace pulse until it matches the phase of a deflection current, and An excellent convergence device that lowers the driving power supply voltage and power consumption by adjusting the phase of the output of the modulation waveform generator circuit by a predetermined amount from the phase of the deflection current, and at the same time enables highly accurate corner convergence. It provides:

[Brief explanation of the drawing]

Figure 1 is a block diagram showing a conventional convergence device.
Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is an explanatory diagram of waveforms necessary for corner convergence, and Figs. 4 and 5 are essential waveform diagrams for explaining the operation of the conventional example. ,
FIG. 6 is a waveform diagram of essential parts of this embodiment. 2... Deflection circuit, 3... Horizontal deflection coil, 4... Vertical deflection coil, 5... Phase advance circuit, 6... Waveform generation circuit, 1...
... Adder, 8 ... Output amplifier, 9 ...
・Convergence coil, 10...Modulation waveform generation circuit, 12...Control circuit, 13...
Separate winding, 14... Second phase advance circuit.

Claims (1)

[Claims] 1. A deflection circuit, a waveform generation circuit that forms a convergence waveform with horizontal and vertical periods from a pulse synchronized with a retrace pulse of a synchronization signal or deflection current, a modulation waveform generation circuit for corner convergence, and the waveform generation circuit. The device includes an amplifier that combines and amplifies the outputs of the modulated waveform generation circuit, and a convergence coil to which the convergence output of the amplifier is applied, and advances the phase of the horizontal period pulses supplied to the waveform generation circuit. A first phase advance circuit and a second phase advance circuit that advances the phase of a horizontal period pulse to the modulation waveform generation circuit are provided, so that the phase of the output of the modulation waveform generation circuit is greater than the phase of the output of the waveform generation circuit. Furthermore, a convergence device is characterized in that it dispenses a predetermined amount.