JPH03143092A - Crt picture tube - Google Patents

Abstract

PURPOSE:To execute the GAIN control of a video amplifier, a cut-off adjustment, and a white balance adjustment by generating a synchronizing pulse for clamping and a white pattern signal which are synchronous to each other using the low pressure winding wire output pulse of a fly-back transformer, and switching them with a pattern changeover switching means. CONSTITUTION:Means 60, 62 for generating the video signals which express the timing pulse for clamping and the white pattern and are synchronous with each other, a pattern changeover switching means 68 which switches a CRT screen with a white pattern mode or a black pattern mode, and a means 66 which detects whether or not an external video signal is inputted to a video input terminal and prohibits the use of the synchronizing pulse for clamping and the white pattern video signal when it is inputted, are provided. Therefore, the low pressure winding wire output pulse of a fly-back transformer 50 is generated in a horizontal fly-back period, so the waveform of this pulse can be formed. Thus, the GAIN control of the video amplification circuit, the cut-off adjustment, and the white balance adjustment can be executed without connecting a special external video signal generator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a CRT receiver, and in particular to a GA of a video amplification circuit.
IN, u! ! It relates to the ability to adjust the power of the CRT, to-off adjustment, and/or white balance adjustment.

[Prior art] Video amplification circuit GAIN, J! ! CRT power-off adjustment, and white balance adjustment are always performed for each receiver at the time of shipment from the factory.

GAIN:A adjustment of the video amplification circuit means the predetermined RlG, B
Video input signal level (e.g. 0.7 VP-P/75
Ω termination), the GAIN of the video amplifier circuit is adjusted so that each of the R, G, and B cathodes has a predetermined video output level (for example, 40 V PP). Cutoff adjustment means adjusting each bias voltage so that the beam current of the CRT is turned off for R, G, and B at the same time near the black level of the video signal. White balance adjustment means that when the white image &(, EI number is input, CR
The purpose is to finely adjust the area ratio for each color signal (RGB) so that each luminance of the output light of the T RGB phosphor becomes a predetermined ratio and represents a predetermined white color (for example, 9300'K) i1+. .

FIG. 4 shows the circuit configuration of the main parts of a conventional CRT receiver. Each color signal R, G, B input from the video input terminal 10
are amplified by the video amplification circuit 12°14.16, respectively, by the clamp circuits 20R, 20G, and 20B.
! The 'L' portion is reproduced and the contrast is adjusted by the contrast adjustment circuit 22. The horizontal synchronizing signal H5 is applied to the clamp circuits 20R720G and 20B.
A clamp pulse CP delayed by a predetermined time is given from the clamp pulse generation circuit 18, and RlG,
B. The clamp voltage of each color signal is adjusted by the BIAS adjustment circuits 21R, 21G, and 21B.

Next, each color signal R, G, B is sent to a video output circuit 3.
After being amplified by 0.0, 32.34, the signal is supplied to the cathode 38.40.42 of the CRT 36.

As a result, the fluorescent screen 44 is irradiated with a beam current corresponding to the intensity of each color signal from these cathodes, and an image is projected on the screen of the CRT 38.

Volumes 46 and 48 are respectively 1st. 2nd G, Do G
This is for adjusting the bias voltage of G1 and G2.

A flyback transformer (FBT) 50 receives a horizontal synchronizing pulse from a horizontal oscillation circuit (not shown) through a horizontal output transistor 52, boosts the voltage, and rectifies the high voltage obtained on the secondary side. Supply high voltage to the CRT anode, etc.

Now, in order to perform GAIN adjustment, cant-off adjustment, and white balance adjustment of the video amplifier circuit in this CRT receiver, a video signal generator 100 is connected to the video signal input terminal 10 as shown in the figure. This video signal generator 100 is a unit that selectively generates a white pattern 7 video signal and a black pattern video signal. First, the video amplification circuit GAINJ!
In order to perform 4 adjustment, the video signal generator 100 generates a white pattern video signal. Then, when the contrast is adjusted to MAX (maximum) in the contrast adjustment circuit 22, R, G is adjusted so that a predetermined output level is obtained for the predetermined R, G, and B video input signal levels.

B, GA[N are adjusted by adjustment circuits 24, 26, and 28.

Next, in order to perform cutoff adjustment, the video signal generator 10
A black pattern video signal is generated at 0.

Then, by adjusting the volume 48, the bias of the second grid G2 is changed to match the critical state (force, to-off point) of whether a bright line appears on the screen of the CRT 36, and further R, G, B R, G, B, BIAS adjustment circuits 21R, 21G, 21 to match each cutoff point
R, G at B.

Adjust the lamp voltage for each B so that the color of the bright line becomes slightly white near the cutoff.

Next, in order to adjust the white balance, the video signal generator n1oO generates each color signal R, G, and B representing a white pattern. Then, R, GAIN adjustment circuit, G, GA
By finely adjusting the volumes of the IN adjustment circuits 26, B, and the GAIN adjustment circuit 28 (Fig. Make sure that regular white appears on the screen.

[Problems to be Solved by the Invention] The above-mentioned methods of GAINA adjustment, cutoff adjustment, and white balance adjustment of a video amplification circuit are merely examples, and various adjustment methods and adjustment circuits are used depending on the model.

However, in both cases, conventionally, a special external video signal generator such as the video signal generator 100 described above has been connected to obtain a black pattern for cutoff adjustment and a white pattern for white balance adjustment. For this purpose, the video signal generator equipment requires a considerable amount of time. In addition, it also took time (man-hours) to connect and disconnect the cable connector of the video signal generator to and from the video input terminal IO.

The present invention has been made in view of such problems, and allows video amplification without connecting a special external video signal generator.
The 1-1 goal is to provide a CRT receiver that can perform GAIN adjustment, power, to-off adjustment, and white balance adjustment of the circuit.

[Means for Solving the Problems] In order to achieve the objects described below, the CRT receiver of the present invention uses timing pulses for clamping and means for respectively generating video signals representing the patterns; and C.
A pattern changeover switch means for switching the R7 screen to white pattern 7 mode or black pattern mode, and detects whether or not an external video signal is input to the video input terminal, and clamps when it is input. The present invention is configured to include means for prohibiting the use of a synchronizing pulse and a white pattern video signal.

Also, in order to achieve the above objective in terms of software, an external video signal is not input to the video input terminal B,! A microcomputer that generates a synchronization pulse for clamping and a video signal representing a white pattern, respectively, and a pattern changeover switch means for switching the CR7 screen to the white pattern mode or the black pattern mode are installed. The structure is equipped with the following features.

[Operation Co-Fly Vanock ◆ The low-voltage winding output pulse of the transformer is generated during the underwater retrace period, so by waveform-shaping this pulse, it is possible to generate a rectangular-wave synchronous pulse having a horizontal frequency. Furthermore, by converting the level of this synchronization pulse, the video signal representing the white pattern (
color signals or color difference signals).

When adjusting the G A I N of the video amplification circuit, the white pattern video value is changed by switching to the white pattern mode using the pattern changeover switch means.
Since it is input to the amplifier, V
Adjust the GAIN of the IDEO amplifier.

When performing cutoff adjustment, the pattern changeover switch means switches to the male pattern mode and applies a synchronizing pulse for clamping to the clamp means, while stopping the output of the white pattern video signal. Then, video signal processing [j
By operating the clamp in a state where no video signal is input to the L path, a video signal that is approximately fixed at the black level can be obtained.

By supplying this to the CRT, a black pattern screen can be obtained, and the cutoff point is adjusted by operating a predetermined adjustment means.

White balance: J! 4! ! ! To do this, the pattern changeover switch means switches to the white pattern mode to output a white pattern video signal and supply it to the video signal processing circuit. At the same time, a synchronizing pulse for clamping is applied to the clamping means. Then, the video signal is clamped at a predetermined (synchronized) timing in the video signal processing circuit, receives 14 direct current components, and is then supplied to the CRT.

As a result, a pattern of white or a color close to white appears on the CRT screen, and the white balance is adjusted by operating a predetermined adjustment means.

In addition, it detects whether or not an external video signal is input to the video input terminal, and when it is input, prohibits the use of the synchronization pulse for clamping and the white pattern video signal according to the present invention, and By inputting only the video signal to the video signal processing circuit and applying an external synchronizing pulse to the clamping means, the external video signal can be displayed normally on the screen.

In addition, the microcomputer eliminates the need for counting or timer calculations like a normal personal computer.
A synchronization pulse and a white pattern video signal that are synchronized with each other can be generated. In this case, the flybar,
I'm sorry for not using the transformer.

[Example 1] The following is a practical example of the present invention with reference to Figs. 1 to 3! Explain an example.

Figure 1 shows the area between the CRT receiver according to the first embodiment.
b) Show the road configuration. FIG. 2 shows waveforms of signals at various parts that are characteristic of this embodiment. In FIG. 1, parts having the same configuration and function as those in FIG. 4 are given the same reference numerals.

According to this embodiment, the synchronous pulse generation circuit 60.chi.1 is added to the conventional CRT receiver. White pattern video signal generation circuit 62. Manual switch 64 for pattern switching. The configuration includes an input signal detection circuit 66 and a switch 68 for switching synchronous signals.

The synchronous pulse generation circuit 60 inputs the pulse HT generated during the underwater retrace period as shown in FIG. FIG. 2 (0) i: Shape the waveform into a rectangular wave pulse HP as shown in f. This pulse HP has a frequency approximately corresponding to the horizontal synchronizing pulse H5, and is used as a synchronizing pulse for clamping at one of the λ terminals 68 of the switch 68.
a, and is also input to the own pattern video signal generation circuit 62.

The white pattern video signal generation circuit 62 includes a circuit for converting the level of the synchronization pulse HP, and each of them is shown in FIG.
Color signals RW and GW have waveforms as shown in .

Bw is generated as a white pattern video signal.

The input signal detection circuit 66 detects whether or not the horizontal synchronization signal H5 is input to the video input terminal 10. If the signal H5 is not input, the input signal detection circuit 66 switches the Sui and Chiro 8 to the input terminal 68a and generates a synchronization pulse. Inputting the synchronization pulse HP from the circuit 60 to the clamp pulse generation circuit 18,
A white pattern video signal (RW.

GIF, 13W) output.

According to this configuration, cutoff adjustment and white balance adjustment are performed as follows without connecting an external video signal generator to the video input terminal 1o.

First, in order to adjust the GAIN of the video amplification circuit, set the pattern changeover switch 64 to the all-white pattern mode (terminal 6
4b) Cut the forest. When this mode is selected, the pattern video signal generation circuit 62 generates a color signal R representing the own pattern.
Output W, G w, B y. On the other hand, the synchronizing pulse HP from the four pulse generating circuits 60 is applied to the clamp pulse generating circuit 18 via the switch 68, and from this circuit 18 is supplied to the recranop pulse CPb1 clamp circuit 18. As a result, the white pattern image is Each color signal RW, GW, BY from the signal generation circuit 62 is sent to the video amplification circuit 12,1.
4.16, where the black level of each color signal is clamped at a predetermined timing by a clamp circuit 2o. After that, each color signal RW, Gv, By outputted from the video amplification circuit 12.14.16 is amplified by the video amplification circuit 30.32.34, and then transferred to the CRT.
36 cathodes 38°40.42. The RlG, B, and GAIN adjustment circuits 24, 26, and 28 are adjusted so that the VIDEO signal level supplied to the cathodes 38, 40, and 42 becomes a predetermined level (for example, 40VP-P).

Next, in order to perform cutoff adjustment, the pattern changeover switch 64 is switched to the all-black pattern mode (terminal 64a). The white pattern video signal generation circuit 62 receiving the output of this switch 64 generates a white pattern video signal (R stomach, G stomach).
Il, BW) are not output.

On the other hand, the synchronizing pulse HP is applied to the clamp pulse generating circuit 18 via the switch 88, whereby the clamp pulse CP is supplied from the clamp pulse generating circuit 18 to the clamp circuit 2o. As a result, the video amplification circuit 12.
Although no video signal is input to circuits 14 and 113, when the clamp circuit 2o operates, a video signal fixed at a black level (clamp level) is output from these video amplification circuits. By setting the volume 48 to a predetermined position, the grid G1 voltage is set to a predetermined voltage, and while adjusting the volume 48, the bias voltage of the grid G2 is controlled. cut·
Adjust to the off point, adjust the other two colors' B I, A S adjustment rod circuit 21R or G or B to match the cut-off point of the color that shines the most, and adjust the three colors at each bias strip. The same should be specifically cut off.

Next, in order to adjust the white balance, set the butter 7 selector switch 64 to the all-white pattern mode (end f-64b).
). When this mode is not selected, the pattern video signal generation circuit 62 generates a color signal R representing a white pattern.
Outputs W, G w, and B w.

On the other hand, the synchronization pulse HP from the synchronization pulse generation circuit 60 is applied to the club/club pulse generation circuit 18 via the switch 68, and the clamp pulse CP is supplied from this circuit 18 to the clamp circuit 18. As a result, each color signal R*, Gw, Bv from the white pattern video signal generation circuit 62 is input to the video amplification circuit 12.14° 16, where the black level of each color signal is clamped at a predetermined timing by the clamp circuit 20. be done.

After that, each color signal RW, GW, BW output from the video amplification circuits 12, 14.16 is sent to the video output circuit 3.
After being amplified by 0.32.34, it is converted into a beam current by the cathodes 38, 40, 42 of the CRT 36, and the beam current is applied to the phosphor screen 44.
emit red, green, and blue light. These three colors of light are mixed (
(addition) and white or a color close to it appears, so use the R, G, AIN adjustment circuit 24°G, GAIN adjustment circuit to make that color a regular white! 11th road 24. B. The GAIN control circuit 28 may be finely adjusted.

When an external video signal is input to the video input terminal 10, the input signal detection circuit 66 detects it and sends the white pattern 7 video signal q (R*) to the white pattern video signal generation circuit 62.
, G W , B W ) No output 'i: Prohibited regardless of the status of Sui and Chiro 4, and switch 6
8 to the input terminal 88a and outputs the horizontal synchronizing pulse HP synchronized with the external video signal to the clamp/clamp pulse generating circuit 18.
be supplied to

As shown in I above, in this embodiment, even if no video signal is input from the outside, the synchronization pulse generation circuit 6O and the pattern video signal generation circuit are generated based on the low 1- winding output pulse HT from the FBT 50. 62 to 0[synchronized clamping synchronous pulse HP and white butter/signal (RW, G
By generating the white pattern signals (RW, B If) and switching the output of the white pattern signal (RW, GWBW) using the pattern changeover switch 64, it is possible to perform GAIN adjustment, power, to-off adjustment, and vote balance adjustment of the video amplification circuit. ing. Therefore, as in the past, special video signal generation 7
A (100) is no longer required, and a large amount of cost is not required, and the effort (man-hour) of connecting and disconnecting cables and connectors to and from the video input terminal 10 can also be saved.

FIG. 3 shows the circuit configuration of the main part of the CRT receiver according to the second embodiment. In the figure, the configuration is similar to that of Figure 1.
Functional parts are marked with the same arrow.

This embodiment is similar to the first embodiment described above]
Pulse generation circuit 60. White pattern video signal port with circuit 6
2. The function of the input signal detection circuit 66 is realized by a microcomputer 70 using software.

That is, the microcomputer 70 receives the horizontal synchronizing signal H5 from the video input terminal 10 or the vertical synchronizing signal H5.
-'r"y V S is monitored, and when it is not input, the same 1tjJ pulse HP and own pattern video signal R1 synchronized with each other by software, that is, by counting or timer calculation processing similar to a normal personal computer.
, Qll, and BW, and selectively generates these white butter 7 video signals RW, according to the position of the pattern changeover switch 64.
Generate GW and BW. Further, the synchronous pulse changeover switch 68 is switched to the terminal 68a side. The microcomputer 70 also performs other controls within the receiver, such as frequency control, single phase control, and DC control.

[Effects of the Invention] The present invention provides the following effects by applying fT to the configuration as described above.

According to the CRT receiver of the first aspect, the low-voltage winding output pulses of the flyback transformer are used to generate synchronous pulsed white pattern signals for clamping that are synchronized with each other, and the white pattern mode (white pattern mode) is set by the pattern changeover switch means. By switching between pattern video signal output) and black pattern mode (white pattern video signal non-output), you can adjust the GAIN tone of the video amplifier! , cutoff adjustment, white rose/
It is possible to make adjustments. Therefore, there is no need for a special video signal generator, which saves a large amount of cost, and also eliminates the man-hours required to connect and disconnect the video signal generator's cable connector to and from the receiver.

In addition, when an external video signal is input to the video input terminal, the use of the white pattern video signal and the synchronization pulse synchronized with it is prohibited, and only the external video signal is input to the video signal processing circuit, and the external By applying a synchronizing pulse to the clamp means, the external video signal can be displayed normally on the screen.

According to the CRT receiver of the second aspect, the microcomputer can be effectively utilized by causing the microcomputer to generate mutually synchronized synchronization pulses and white pattern video signals using software.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the circuit configuration of the main parts of a CRT receiver according to the first embodiment of the present invention, and FIG. 2 is a diagram showing the waveforms of signals in each part that are characteristic of the first embodiment. , FIG. 3 is a block diagram showing the circuit configuration of the main part of the CRT receiver according to the second embodiment of the present invention, and FIG.
FIG. 2 is a block diagram showing the circuit configuration of the main parts of the RT receiver. In the drawings, 10... video signal input terminal, 12.14. IE3...Video amplification circuit, 18...
Clamp pulse generation circuit, 2OR, G, B...R, G, B clamp circuit, 21
R, G, B...R, G, B, BIAS adjustment circuit 24
．． 2E3.28...R, G, B adjustment circuit, 36...
...CRT. , 18... Volume, 50... Flyback transformer (FBT) 60.
...Synchronization noise generation circuit, 62... Own pattern video signal generation circuit, 64...
・Pattern mode selection switch, 66... Input signal detection circuit, 68... Synchronous pulse switching ID circuit for clamp, 70
...Microcomputer 9゜

Claims (2)

[Claims] (1) Means for generating mutually synchronized timing pulses for clamping and a video signal representing a white pattern based on the low-voltage winding output pulses of a flyback transformer, and a means for setting a CRT screen to a white pattern mode or a black pattern mode. a pattern changeover switch means for switching; and detecting whether or not an external video signal is input to the video input terminal, and when it is input, using the synchronization pulse for clamping and the white pattern video signal. A CRT receiver characterized by comprising means for prohibiting the following: (2) A microcomputer that generates a synchronizing pulse for clamping and a video signal representing a white pattern that are synchronized with each other when no external video signal is input to the video input terminal, and a CRT screen that sets the CRT screen to white pattern mode or black pattern mode. A CRT receiver, comprising: pattern changeover switch means for changing patterns; and a CRT receiver.