JPS6239594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide a color purity adjustment device that can accurately and stably adjust the color purity of a color television receiver in a short time.

The conventional beam landing indicating device applies a 60Hz pulse generated by an optical sensor to a phase separation circuit through a 15Hz bandpass filter, and then
In addition to a phase discriminator for and Y, the X and Y components are separated, passed through a low-pass filter, and displayed on an oscilloscope by switching. For this reason, a phase delay due to circuit constants occurs in band pass filters, low pass filters, etc., resulting in a disadvantage that vectors on the display oscilloscope are greatly deviated. In addition, the deviation of the zero point is large due to drift of the phase discrimination circuit constant due to temperature changes, etc.
There was a problem with color purity adjustment. Furthermore, the display on the oscilloscope had two display marks of the same type, which was an obstacle to the adjustment work.

In order to solve these drawbacks, the present invention improves the detected pulse processing means and the monitor display means.

An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIGS. 1 and 2, 1 and 39 are photoelectric conversion elements, and 2 and 40 are photoelectric conversion elements 1 and 9.
5 is the amplifier 2, 4 which amplifies the output current of
It is a deflection magnetic field generator synchronized with the output current of 0, and is applied to vertical deflection coils 41 and 42 and horizontal deflection coils 43 and 44, which are installed at two appropriate positions on the left and right sides of the color cathode ray tube screen, in accordance with the vertical scanning period of the television receiver. Deflection currents (Fig. 6 a, b) that are synchronized and have a phase difference of 90° are applied in the vertical and horizontal directions at t ₁
A deflection magnetic field up to ~ _t4 is generated to deflect the electron beam on the color cathode ray tube in the following order: up, right, down, and left.

Further, 48 and 49 are a left-side detection pulse processing circuit and a right-side detection pulse processing circuit, both of which are composed of exactly the same circuits, and include a deflection coil (not shown) which is one of the color purity adjustment operations of a color television receiver. ) functions symmetrically and performs exactly the same operation when adjusting the position. Therefore, in FIG. 2, the left side detection pulse processing circuit 48 will be explained as a representative.

In the left side detection pulse processing circuit 48, 8,
9, 10, 11 are semiconductor switches inserted on the output side of amplifier 2, 12, 13, 14, 15 are peak holding circuits, 16, 17, 18, 19 are semiconductor switches, 20, 21, 22, 23 are samples Hold circuits 24, 25, 26, and 27 are semiconductor switches for resetting the respective peak holding circuits 12, 13, 14, and 15; 29 and 30 are the outputs of the sample and hold circuits 20 and 21, respectively; sample and hold circuits 22 and 23; This is a differential amplifier that takes the output of the circuit as its input, and generates the difference voltage between each circuit as its output. Further, 31 and 32 are respective differential amplifiers 29 and 30.
This is a semiconductor switch inserted on the output side of the

7 is a switching pulse generator, which controls the left detection pulse processing circuit 4 according to the timing shown in FIG.
8. Open/close control of semiconductor switches 8 to 11, 16 to 19, and 24 to 27 in the right detection pulse processing circuit 49.

35 is a display oscillator for creating a marking signal for display identification, and 36 is this display oscillator 3.
5, and its output is superimposed on the outputs of the respective differential amplifiers 29 and 30. 37 are reference cross lines A ₁ , A ₂ shown in FIGS. 3 to 5.
This is a cross line generator for displaying on the oscilloscope 38, and generates a sawtooth wave in synchronization with the display oscillator 35. 45 is a display oscillator 35
A display switching signal generator synchronized with the semiconductor switches 31 and 32, the semiconductor switches 33 and 34 inserted between the cross line generator 37 and the oscilloscope 38, and the same right detection pulse as the semiconductor switches 31 and 32. Processing circuit 49
The semiconductor switches 46 and 47 inside are controlled to open and close at the timing shown in FIG.

Next, its operation will be explained.

In the configuration shown in Fig. 1, the photocurrent generated in the photoelectric conversion elements 1, 39 arranged on the surface of the cathode ray tube of the color television receiver is amplified by the amplifiers 2, 40, and the output pulse (Fig. 6d) is It is applied to the switches 8 to 11, but also to the switching pulse generator 7 and the deflection magnetic field generator 5 at the same time. The photocurrents generated in the photoelectric conversion elements 1 and 39 are synchronized with the vertical scanning period of the color cathode ray tube, and the outputs applied from the amplifiers 2 and 40 to the switching pulse generator 7 and the deflection magnetic field generator 5 are also synchronized with the vertical scanning period of the color cathode ray tube. Synchronized with the scanning cycle. Therefore, the output pulses of the switching pulse generator 7 (t ₁ to t ₄ in FIG. 8) and the outputs of the deflection magnetic field generator 5 (a, bt ₁ to t ₄ in FIG. 6) are also applied to the color cathode ray tube vertical scanning. Synchronize with the cycle. Now, if the vertical deflection current t ₁ shown in FIG. 6a is flowing through the vertical deflection coil 41 (at this time, as is clear from FIG. 6b, no current flows through the horizontal deflection coil 43), then as shown in FIG. The beam is deflected upward as shown at the left end of FIG. 1C, and a photocurrent proportional to the amount of light emitted from the phosphor screen at that point in time is generated in the photoelectric conversion element 1. The generated photocurrent is amplified by the amplifier 2 and applied to the semiconductor switches 8 to 11 connected in parallel to each other on the output side thereof.

On the other hand, the switching pulse shown in number 1 in FIG. 8 is applied to the gate of the semiconductor switch 8 from the switching pulse generator 7 which generates switching pulses in synchronization with the vertical scanning period of the color television receiver. , the semiconductor switch 8 becomes conductive, and the output pulse of the amplifier 2 is passed through the peak holding circuit 12.
The peak voltage value of the input pulse voltage is held. At this time, the semiconductor switch 24 is open as shown in FIG. 8, but it was closed in the previous cycle, putting the peak holding circuit 12 in the reset state.

Next, when the horizontal deflection current _t2 shown in FIG. 6b flows through the horizontal deflection coil 43 (during this period, no vertical deflection current flows), the electron beam is deflected to the right as shown in FIG. A photocurrent proportional to the amount of light emitted from the phosphor screen at a time is generated in the photoelectric conversion element 1,
The current is amplified by the amplifier 2 and the semiconductor switch 8
- added to 11. Note that FIG. 6d shows the output pulse voltage waveform of the amplifier 2.

On the other hand, at this time, the switching pulse shown in the second line in FIG. 8 is applied from the switching pulse generator 7 to the semiconductor switch 10, and the semiconductor switch 1
0 is conductive, and the output pulse of the amplifier 2 is input to the peak holding circuit 14, which holds the peak voltage value of the input pulse voltage.

Then, in the next vertical deflection current t ₃ and also in the next horizontal deflection current t ₄ , each of the above-mentioned deflection currents t ₁ and t ₂
As in the case of , switching pulses are sequentially applied to the semiconductor switches 9 and 11, and the peak holding circuit 1
The output pulse voltage of the amplifier 2 is added to 3 and 15 to maintain the peak voltage value.

When a switching pulse synchronized with _t2 is applied from the switching pulse generator 7 to the gate of the semiconductor switch 16 as shown in FIG. The voltage input to the circuit 20 and previously input and held is corrected to the newly input voltage value.

Next, when a switching pulse synchronized with _t3 is applied to the gate of the semiconductor switch 18, the semiconductor switch 18 becomes conductive, and the holding voltage of the peak holding circuit 14 is input to the sample hold circuit 22, and the holding voltage that was previously input and held is input to the sample hold circuit 22. The previously input voltage value will be corrected to the newly input voltage value.

By sequentially applying switching pulses to the semiconductor switches 17 and 19 in the same manner as the semiconductor switches 16 and 18, the holding voltages of the peak holding circuits 13 and 15 pass through the semiconductor switches 17 and 19 at t ₄ and t ₁ , respectively. Sample hold circuit 2
1 and 23, and the previously held voltage value is corrected to the newly input voltage value.

Therefore, each sample hold circuit 20 to 23
An output voltage corresponding to the holding voltage value is constantly outputted from the sample and hold circuits 20 and 21, and the outputs of the sample and hold circuits 20 and 21 are applied to a differential amplifier 29 for calculation.
A differential voltage between sample and hold circuits 20 and 21 is output from a differential amplifier 29. That is, a voltage representing the vertical deviation of the electron beam is output.

On the other hand, the outputs of the sample and hold circuits 22 and 23 are applied to a differential amplifier 30, and the differential voltage between the sample and hold circuits 22 and 23 is outputted from the differential amplifier 30. That is, the differential amplifier 30 outputs a voltage representing the horizontal deviation of the electron beam.

Here, a marking signal for display identification is added. The positive phase or negative phase of the output of the sawtooth wave generator 36 synchronized with the display oscillator 35 is superimposed on the outputs of the differential amplifiers 29 and 30, respectively. Here, when a switching pulse from the display switching pulse generator 45 synchronized with the display oscillator 35 is applied to the gates of the semiconductor switches 31 and 32 to make them conductive, the output voltage of the differential amplifier 29 becomes A differential amplifier 3 is installed on the vertical axis of the scope 38.
Each output voltage of 0 is input to the horizontal axis of the oscilloscope 38 and displayed as a vector.

This display shows that the sawtooth waveform is superimposed on the output of each differential amplifier 29, 30, so the differential amplifier 2
When a sawtooth waveform in positive phase is superimposed on the outputs of differential amplifiers 9 and 30, a right-sloping line display (see B in FIGS. 3 to 5) with a length corresponding to the amplitude of the sawtooth waveform is obtained, and one differential amplifier 29 When a positive-phase sawtooth voltage is superimposed on the output of the other differential amplifier 30 and an anti-phase sawtooth waveform is superimposed on the output of the other differential amplifier 30, a left-sloping line with a length corresponding to the amplitude of the sawtooth waveform is displayed.

This depends on the type of display, the phase of the sawtooth wave,
By appropriately adjusting the amplitude and superimposing it on the output of the differential amplifier, it is possible to support many types of displays. In the case of FIG. 1, there are only two types of vector displays: the left side detection pulse processing circuit 48 has a right slope (line B in FIGS. 3 to 5), and the right side detection pulse processing circuit 49 has a left slope (line 3). Line C in Figures to Figure 5) is adopted in each case.

Further, in the present invention, in the color purity adjustment work, the target point of the work, that is, the differential amplifiers 29 and 3
A cross line is displayed on the oscilloscope 38 to clearly display the point where the output becomes zero. When the display switching pulse generator 45 synchronized with the display oscillator 35 first applies a switching pulse to the gate of the semiconductor switch 33, the semiconductor switch 33 becomes conductive and the display oscilloscope is activated by the cross line generator 37. One cycle of the sawtooth waveform is sent to the vertical axis of 38, and a vertical line whose length corresponds to the amplitude of the sawtooth waveform is
Display A ₁ . Then, when a switching pulse of the next cycle is applied to the semiconductor switch 34 from the display switching pulse generator 45, the semiconductor switch 34 becomes conductive, and the cross line generator 37 causes the horizontal axis of the display oscilloscope 38 to be sawed. One cycle of the waveform is sent, and a horizontal line _A2 whose length corresponds to the amplitude of the sawtooth waveform is displayed. these vertical lines
A ₁ and horizontal line A ₂ are crosses that intersect at their respective centers, and the intersecting centers represent the zero point, that is, the origin of color purity adjustment.

The cross line is completed in the above two cycles, but
The period is set to a period at which flickering is not felt.
The timing chart is shown in FIG. As described above from FIG. 7, in the first cycle, the right-sloping line B is created, in the next cycle, the left-slanting line C is created, and in the next cycle, the vertical line _A1 of the cross line is created, It can be seen that the horizontal line _A2 of the cross line is created in the next cycle.

The above are the main parts of the color purity adjustment device for a color television receiver, but consideration has been given to further increasing accuracy by adding two additional functions.

One of them is an automatic brightness level adjustment circuit 28. The outputs of the sample and hold circuits 20 and 21 correspond to the deflection magnetic fields caused by the vertical deflection currents t ₁ and t ₃ shown in FIG. 6a, and operate differentially with respect to each other. That is, when the electron beam is in an upward mislanding state, at t ₁ the electron beam is swung further upwards and the brightness level further decreases, but at t ₃ the beam is swung downwards and the brightness level is t ₃ This is improved compared to before applying a magnetic field of .

Therefore, sample and hold circuits 20 and 21
The output voltages of the two voltages change in a complementary manner, and their average level is always constant. Focusing on this point, the gain of the amplifier 2 is automatically controlled using this voltage depending on the brightness level of the color television receiver. Therefore, vector level errors on the display oscilloscope 38 due to differences in brightness levels between color television receivers can be reduced. Of course, this circuit is also installed in the right detection pulse processing circuit 49.

Another function is to apply a reference signal that can confirm that the adjustment device maintains a normal state without errors immediately before or after the start of color purity adjustment work on a color television receiver. be.

For this purpose, a test signal generator 3 is provided, and this test signal generator 3 generates a test signal of the same frequency as the vertical scanning frequency of the color television receiver, and during the period when color purity adjustment work is not performed, That is, the relay switch 4 is closed from the end of the color purity adjustment operation until immediately before the start of the next color purity adjustment operation, and this test signal pulse is applied to the amplifiers 2 and 40. Since the test signal pulse is at the same level from _t1 to _t4 , the level difference between sample and hold circuits 20 and 21 and between sample and hold circuits 22 and 23 is both zero volts. Therefore, the output voltage of the differential amplifiers 29 and 30 is also zero volts, and the display oscilloscope 3
8 indicates the left side, right side detection pulse processing circuit 48,
49 are both zero, and all vector representations are located at the origin. This state is shown in FIGS. 3a and 3b.

By confirming that all the displays are located at the origin in this way, it is possible to confirm that the circuits after the amplifiers 2 and 40 are normal.

Here I will briefly explain how to make adjustments.

A second monitor is placed on the cathode ray tube surface of the color television receiver to be adjusted, which is receiving an all-white white pattern.
As shown in the figure, left and right photoelectric conversion elements 1 and 39 and each deflection coil 41 to 4 are placed in balanced positions.
4 and put the color purity adjustment device into operation as described above, the beam landing state of the color television receiver to be adjusted is immediately displayed on the tube surface of the display oscilloscope 38.

The adjustment operator pays close attention to the tube surface of the display oscilloscope 38 and moves the deflection yoke (not shown) of the color television receiver to be adjusted so that the right-slanted line B and the left-slanted line C overlap at the center. ) position forward or backward. After that, operate the pulley magnet (not shown) and align the center of the left and right slope lines B and C that you overlapped earlier with the cross line.
The color purity adjustment work is completed by adjusting it so that it is located at the center of A ₁ and A ₂ .

Figures 3a and b show the state in which the adjustment has been completed, that is, there is no mislanding. However, if the electron beam is deviated both vertically and horizontally, as shown in Figure 4b, for example, Figure 4a As shown in the figure, the right-slanted line B and the left-slanted line C intersect at the center, but are displayed at positions away from the cross lines A ₁ and A ₂ . Therefore, in this case, the adjustment operator only has to operate the pulley magnet so that the centers of the left and right slope lines B and C are located at the center of the cross line. In addition, when the electron beams are shifted left and right in opposite directions as shown in Figure 5b, the right-sloping line B and the left-slanting line C do not intersect and form a cross line, as shown in Figure 5a. It is located on the horizontal line A ₂ . Therefore, in this case, the position of the deflection yoke may be moved rearward.

It is also conceivable to arrange one photoelectric conversion element at the center of the front surface of the color cathode ray tube, but in this case, it is impossible to adjust the position of the deflection yoke, which is disadvantageous in practice. Note that in this case, the sawtooth wave generator 36 may not be used.

As explained above, according to the present invention, the color purity adjustment of a color television receiver can be performed with high precision and in a short time. Additionally, by installing an automatic brightness level adjustment circuit to correct the brightness level difference between color television receivers to be adjusted, vector level errors on the oscilloscope can be reduced, and color purity can be further improved. By adding a test signal that serves as a reference signal to this adjustment circuit and displaying it during periods when adjustment work is not being performed, it is possible to check whether all circuits from the amplifier to the oscilloscope are operating normally. I can do it.

[Brief explanation of the drawing]

Fig. 1 is an overall block diagram of a color purity adjustment device for a color television receiver according to an embodiment of the present invention, and Fig. 2 shows a state in which a photoelectric conversion element and a deflection coil in the same device are installed in a color television receiver. Figures shown, Figure 3a, Figure 4a, Figure 5a
are diagrams showing the state of the beam landing display on the display oscilloscope tube, Figure 3b, Figure 4b,
Figure 5b is a diagram showing the beam landing state of a color television receiver, Figures 6a and b are waveform diagrams of the vertical and horizontal deflection currents, and Figure 6c is the beam landing state due to the vertical and horizontal deflection currents. Figure 6d is a diagram showing the output pulse voltage waveform from the amplifier, Figure 7 is a diagram showing a timing chart for creating a right slope line, a left slope line, and a cross line, and Figure 8 is a diagram showing switching. FIG. 3 is a diagram showing a timing chart of each semiconductor switch by a pulse generator. 1, 39...Photoelectric conversion element, 2, 40...Amplifier, 3...Test signal generator, 5...Deflection magnetic field generator, 7...Switching pulse generator, 8-1
1, 16-19, 24-27...Semiconductor switch, 12-15...Peak holding circuit, 20-23
... Sample hold circuit, 28 ... Automatic brightness level adjustment circuit, 29, 30 ... Differential amplifier, 31
~34,46,47...semiconductor switch, 35...
...Display oscillator, 36...Sawtooth wave generator, 3
7... Cross line generator, 38... Display oscilloscope, 41, 42... Vertical deflection coil,
43, 44...Horizontal deflection coil, 45...Display switching pulse generator, 48...Left side detection pulse processing circuit, 49...Right side detection pulse processing circuit.

Claims (1)

[Scope of Claims] 1. First and second photoelectric conversion elements arranged on the left and right sides of the front surface of a color cathode ray tube;
a deflection means for deflecting the electron beam on the surface of the color cathode ray tube vertically and horizontally with output pulses generated in the photoelectric conversion element of the color cathode ray tube in synchronization with the vertical scanning period of the color cathode ray tube; first to fourth peak holding circuits that hold the peak voltage of the output of the photoelectric conversion element; and hold the peak voltage of the output of the second photoelectric conversion element at each time point when the electron beam is deflected vertically and horizontally. fifth to eighth peak holding circuits; first to fourth and fifth to eighth sample and hold circuits that hold the holding voltage until a new voltage output from each of the peak holding circuits is input; The first and second electrodes maintain the output voltage when the electron beam is deflected up and down.
a sample-and-hold circuit, first and third differential amplifiers that generate a difference voltage between the outputs of the fifth and sixth sample-and-hold circuits, and a third differential amplifier that holds the output voltage when the electron beam is deflected left and right. and a fourth sample-and-hold circuit; second and fourth differential amplifiers that generate a voltage difference between the outputs of the seventh and eighth sample-and-hold circuits; A sawtooth wave generator for superimposing the respective output voltages on the outputs of the third and fourth differential amplifiers to display a right-sloping line and a left-sloping line on a display oscilloscope, and a final target point for color purity adjustment. a cross-line generator that shows the output on the display oscilloscope, the outputs of the first and second and third and fourth differential amplifiers, and the output of the cross-line generator for sequentially switching and supplying the display oscilloscope to the display oscilloscope. Color purity of a color television receiver, characterized in that it is equipped with a display switching pulse generator, a display oscillator that controls the above-mentioned sawtooth wave generator, cross line generator, and display switching pulse generator. Adjustment device. 2. Input the output of a sample and hold circuit that holds the output voltage when the electron beam is deflected vertically or horizontally, and add the output voltage to the amplifier inserted on the output side of the first and second photoelectric conversion elements. 2. The color purity adjustment device for a color television receiver according to claim 1, further comprising an automatic brightness level adjustment circuit for controlling the gain of this amplifier according to the brightness of each color television receiver. 3. After installing a test signal generator and completing the adjustment work for the color television receiver, the test signal from the test signal generator is displayed on the display oscilloscope, and the circuit from the photoelectric conversion element to the display oscilloscope is 2. The color purity adjustment device for a color television receiver according to claim 1, further comprising the step of checking whether or not the device is operating normally.