JPH046313Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a beam index type color television receiver that controls the irradiation position of an electron beam using an index pulse signal. The purpose of this invention is to correctly control the irradiation position of an electron beam and reproduce an image without color shift even when a noise pulse signal is mixed into a forming pulse signal.

A conventional beam index type color television receiver of this type has three primary color phosphors, that is, red phosphors, in the form of stripes perpendicular to the horizontal scanning direction of the electron beam, on the inner surface of the face plate of the picture tube.
A green phosphor and a blue phosphor are repeatedly arranged in the horizontal scanning direction in the order of, for example, a red phosphor, a blue phosphor, a green phosphor, a red phosphor, and so on.
On the inner surface of the primary color phosphor layer, striped index phosphors perpendicular to the horizontal scanning direction are repeatedly arranged in the horizontal scanning direction in correlation with the three primary color phosphors to form a phosphor layer. .

Then, the fluorescent layer portion is swept and irradiated with an electron beam from a single electron gun to perform color reproduction, and
An index optical signal generated when the index phosphor is swept is converted into an electrical signal by a photoelectric converter, and the index signal is output from the converter.

Further, the index signal is input to a pulse processing section to be pulsed, and an index pulse signal is formed based on the pulse signal formed by the pulse processing section, and the irradiation position of the electron beam is determined by the index pulse signal. Control.

Therefore, if a noise pulse signal is mixed into the formed pulse signal outputted from the pulse processing section, the phase of the index pulse signal is shifted and the irradiation position of the electron beam is shifted, resulting in so-called color shift.

This idea was made with the above points in mind, and includes three primary color phosphors arranged repeatedly on the inner surface of the face plate of the picture tube, and a correlation with the three primary color phosphors. A phosphor layer section having striped index phosphors arranged repeatedly is formed, and index light is emitted from each index phosphor by sweeping an electron beam emitted from a single electron gun to the phosphor layer section. A beam index type that generates a signal, converts the index optical signal into an electric signal, pulses the index signal to form an index pulse signal, and controls the irradiation position of the electron beam based on the index pulse signal. In a color television receiver, a pulse processing section that pulses the index signal; a first counting section that outputs a plurality of first counting pulse signals having different phases by counting pulse signals formed by the processing section; The time constant is set to be shorter than one cycle of the index pulse signal, and when the forming pulse signal is the index pulse signal, one cycle of the index pulse signal is set.
A shaped pulse signal having a predetermined pulse width shorter than the index pulse signal is output, and when the shaped pulse signal is a noise pulse signal having a shorter cycle than the index pulse signal, the pulse width of the shaped pulse signal is set to the pulse width of the shaped pulse signal during the continuous input period of the noise pulse signal. a retriggerable multivibrator whose width is variable; a second counting unit that outputs a plurality of second counting pulse signals having different phases by counting the shaped pulse signals; the forming pulse signal, each of the first counting pulses; a decoder section that forms and outputs a plurality of output pulse signals having different phases for the index pulse signal synchronized with the formed pulse signal by a logical operation of the signals; a comparison unit that detects a phase change in the formed pulse signal due to the noise pulse signal by comparing the signals, and selectively outputs a switching pulse signal from a plurality of output terminals according to the phase change of the formed pulse signal; and an output section that switches and outputs each of the output pulse signals by a logical operation of the switching pulse signal and each of the output pulse signals, and outputs an index pulse signal whose phase does not change before and after the noise pulse signal. A beam index type color television receiver is provided.

Therefore, according to the beam index type color television receiver of this invention, even when a noise pulse signal is mixed into the formed pulse signal outputted from the pulse processing section, the noise pulse signal is detected before and after the noise pulse signal. There is no phase shift of the index pulse signal, color shift is prevented, and stable image reproduction can be performed.

Next, this invention will be explained in detail with reference to drawings showing one embodiment thereof.

In FIG. 1, 1 is a pulse input terminal into which the formed pulse signal of the pulse processing section shown in FIG. The rising edge of the pulse signal is differentiated and the differentiated pulse signal shown in FIG. 2b is output.

Note that R, B, and G in the figure indicate pulse signals corresponding to the irradiation positions of the red phosphor, blue phosphor, and green phosphor, and N indicates a noise pulse signal.

5 is one of the 1/3 frequency dividing circuits forming the first counting section, which counts the forming pulse signals inputted to the clock input terminal ck, and divides the number of pulses into the first counting section as shown in FIG. 2c, d, and e. Three first counting pulse signals having different phases are outputted from the third Q output terminals qa, qb, and qc, respectively.

Reference numeral 6 denotes a retriggerable monostable multivibrator, in which the differential pulse signal is input to the trigger input terminal t, and the time constant of the resistor 7 and capacitor 8 is used as shown in Fig. 2 f. , when the formed pulse signal is an index pulse signal, a shaped pulse signal with a pulse width τ1 shorter than one period T of the index pulse signal is output from the Q output terminal q, and when the formed pulse signal is a noise pulse signal, A shaped pulse signal with a pulse width τ2 during the continuous input period of the noise pulse signal is output to the Q output terminal q.
Output only one item from. 9 is a power supply terminal.

10 is the other 1/3 frequency divider circuit forming the second counting section, and the shaped pulse signal is input to the clock input terminal ck, as shown in FIG. 2g, h, and i.
Three second count pulse signals having different phases are output from the first to third Q output terminals qa, qb, and qc, respectively.

11, 12, 13 are the first parts forming the comparison part 14.
or 3D type flip-flops (hereinafter referred to as first to third FF), and the data input terminals d of each FF 11 to 13 are connected to the output terminals qa,
The second counting pulse signals of qb and qc are inputted, and the first counting pulse signal of the output terminal qa of the frequency dividing circuit 5 is inputted to the trigger input terminal t of each FF 11 to 13. As shown in k and l, a switching pulse signal is alternatively output from the Q output terminal q of each FF 11 to 13.

15 is an inverter for inverting the forming pulse signal;
16 is the 2nd Q of the inverter 15 and the frequency divider circuit 5
an AND gate connected to the output terminal qb; 17 an AND gate connected to the pulse input terminal 1 and the first Q output terminal qa of the frequency divider circuit 5; 18 an OR gate connected to both AND gates 16 and 17;
19 is the 3rd Q of the inverter 15 and the frequency divider circuit 5
An AND gate connected to the output terminal qc, 20 an AND gate connected to the pulse input terminal 1 and the second Q output terminal qb of the frequency divider circuit 5, 21 an OR gate connected to both AND gates 19 and 20,
22 is the 1st Q of the inverter 15 and the frequency dividing circuit 5
An AND gate connected to the output terminal qa, 23 an AND gate connected to the pulse input terminal 1 and the third Q output terminal qc of the frequency dividing circuit 5, 24 an OR gate connected to both AND gates 22 and 23,
25 is the inverter 15 and each gate 16 to 24
This is the degouda part formed by Fig. 2 m,
As shown in n, o, each or gate 18, 21, 2
4 outputs three output pulse signals having different phases for the index pulse signal synchronized with the forming pulse signal.

26 is an AND gate connected to the Q output terminal q of the first FF11 and the OR gate 18; 27 is the AND gate connected to the Q output terminal q of the first FF11 and the OR gate 18;
AND gate connected to Q output terminal q of 2FF12 and OR gate 21, 28 is Q of 3rd FF13
The AND gate 29 connected to the output terminal q and the OR gate 24 is an OR gate into which the outputs of the AND gates 26 to 28 are input, and the index pulse signal is sent to the pulse output terminal 30 as shown in FIG. Output. 31 is each AND gate 2
6 to 28 and an OR gate 29.

That is, the forming pulse signal of the pulse input terminal 1 is frequency-divided by the frequency dividing circuit 5, and each first counting pulse signal of the frequency dividing circuit 5 is divided in phase by the degoder section 25 at the next stage.
Each 0° corresponding to the position of each primary color phosphor,
120°, 240°, and repetition frequencies are converted into output pulse signals of triplet frequencies of the three primary color phosphors.

Conventionally, one of the output pulse signals is used as an index pulse signal, and an image is reproduced by mixing a separately supplied color signal and an index pulse signal consisting of the output pulse signal. If the forming pulse signal is mixed with a signal other than the regular index pulse signal, that is, a noise pulse signal with a cycle shorter than one cycle T of the index pulse signal, the number of input noise pulse signals is determined based on the number of input noise pulse signals. , n, o, the phase of each output pulse signal after the noise pulse signal is 120° or more than before the noise pulse signal.
The delay is 240°, and the color of the playback screen is also 120° or
It shifts by 240°.

Therefore, multivibrator 6, frequency dividing circuit 1
0, a comparison section 14 and an output section 31 are provided, and the formed pulse signal is inputted to the multivibrator 6 through the differentiating circuit 12, and at this time, the time constant of the multivibrator 6 is set to be shorter than one period T of the index pulse signal. Blocks shorter period noise pulse signals.

Therefore, the shaped pulse signal outputted from the multivibrator 6 has a pulse width τ1 of the above-mentioned time constant when the shaped pulse signal is an index pulse signal, as shown in FIG. In the case of a pulse signal, the pulse width changes to τ2 during the input period of the noise pulse signal.

And a frequency divider circuit 1 into which the shaped pulse signal is input.
0 counts the pulse signals from which the noise pulse signal has been removed and outputs each second counted pulse signal.

Furthermore, a comparison section 14 consisting of each FF 11 to 13
In order to use the output pulse signal corresponding to the position of the red phosphor as the index pulse signal during normal operation,
Each of the second counting pulse signals and the second counting pulse signal of the frequency dividing circuit 5
Compare with the first counting pulse signal of 1Q output terminal qa,
Determine the number of consecutive inputs of noise pulse signals, and find that the number of inputs is 3m (m = 0, 1, 2, 3, ...)
In other words, when the phase of the index pulse signal does not shift due to the noise pulse signal, the first FF
A switching pulse signal is output from the Q output terminal q of FF 11, and when there are 3m+1, that is, when the phase of the index pulse signal is shifted by 120° due to the noise pulse signal, a switching pulse signal is output from the second FF 12, and when there are 3m+2, that is, when the phase of the index pulse signal is shifted by 120°, When the phase of the index pulse signal is shifted by 240 degrees due to the noise pulse signal, the third FF circuit 13 outputs a switching pulse signal.

Then, in response to the switching pulse signal outputted from the comparison section 14, the output section 31 switches and outputs each output pulse signal to the pulse output terminal 30, so that the index pulse signal at the output terminal 30 is changed as shown in FIG. , even when a noise pulse signal is mixed in, there is no phase shift before or after the noise pulse signal, and the irradiation position of the electron beam is prevented from shifting due to the noise pulse signal, preventing color shift and stable image reproduction. can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the beam index type color television receiver of this invention.
2A to 2P are waveform diagrams for explaining the operation of FIG. 1. 1...pulse input terminal, input...differentiation circuit,
5, 10... 1/3 frequency divider circuit, 6... Monostable multivibrator, 14... Comparison section, 25... Degoder section, 31... Output section, 30... Pulse output terminal.

Claims (1)

[Claims for Utility Model Registration] Three primary color phosphors arranged repeatedly on the inner surface of the face plate of a picture tube;
forming a phosphor layer having striped index phosphors arranged repeatedly in correlation with the primary color phosphors, and sweeping an electron beam emitted from a single electron gun to the phosphor layer to remove each of the index phosphors; a beam that generates an index optical signal from the electron beam, pulses the index signal obtained by converting the index optical signal into an electric signal to form an index pulse signal, and controls the irradiation position of the electron beam based on the index pulse signal; In an index type color television receiver, a pulse processing section that pulses the index signal; and a first pulse processing section that outputs a plurality of first counting pulse signals having different phases by counting pulse signals formed by the processing section.
a counting section; a time constant set to a time constant shorter than one cycle of the index pulse signal, and outputting a shaped pulse signal having a predetermined pulse width shorter than one cycle of the index pulse signal when the forming pulse signal is an index pulse signal; a retriggerable multivibrator that changes the pulse width of the shaping pulse signal to the width of a continuous input period of the noise pulse signal when the shaping pulse signal is a noise pulse signal with a shorter period than the index pulse signal; a second counting unit that outputs a plurality of second counting pulse signals having different phases by counting the shaped pulse signals; and an indexer that is synchronized with the forming pulse signal by a logical operation of the forming pulse signal and each of the first counting pulse signals. a decoder unit that forms a plurality of output pulse signals with different phases for Tx pulse signals; and a decoder unit that compares each of the second counting pulse signals and the predetermined first counting pulse signal to generate the formed pulse signal based on the noise pulse signal. detects the phase change of
a comparison unit that selectively outputs a switching pulse signal from a plurality of output terminals according to a phase change of the formed pulse signal; and a comparison unit that switches each of the output pulse signals by a logical operation of the switching pulse signal and each of the output pulse signals. and an output section for outputting an index pulse signal whose phase does not change before or after the noise pulse signal.