JPS6341474B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an index color television receiver using a beam index color picture tube, and is disclosed in Japanese Patent Publication No. 50-34388 and Japanese Patent Application Laid-Open No. 53-1989.
-Relating to improvements in the technology disclosed in Publication No. 72523.

FIG. 1 shows the index type color picture tube described in the above-mentioned Japanese Patent Publication No. 34388/1988, and FIG. 2 shows the configuration of a color television receiver using this. In Fig. 1, 4 is an electron gun, 5 is a deflection coil, and 6 is a light-emitting phosphor stripe consisting of red (R) 6R, green (G) 6G, blue (B) 6B, and the beam. They are repeatedly arranged in the main deflection direction. Reference numerals 7 and 8 designate metal back electrodes made of aluminum or the like, which are divided into an effective scanning screen area 8 and its peripheral area 7. Projections 7' are provided at the top of the screen and interlock with each other in a comb-like manner. The electrode 7 is provided with an extension 7'' extending in the vertical direction. Reference numeral 10 is an auxiliary electrode for beam deflection, and as will be described later, the location of the beam scanning speed caused by the main deflection by the deflection coil 5 is provided. It is used to correct the non-uniformity due to

A method of projecting a color image using this index type color picture tube will be explained with reference to FIG. At the start of vertical scanning, the electron beam emitted from the electron gun 4 scans the index electrode 7 provided at the top of the effective screen, and the signal obtained is amplified by the amplifier 12 and then amplified by the pulse shaping circuit 13. The waveform is shaped, enters the memory circuit 14, and is stored for one field. Then, this is read every subsequent horizontal scanning period, compared with a signal from a certain reference frequency generator 15, and detected by the frequency detection circuit 16, whereby the scanning speed of the electron beam is detected. This is amplified and added to the auxiliary deflection electrode 10 to make the scanning speed of the beam uniform. On the other hand, the signal from the index electrode 7 (b7'' in FIG. 1) obtained at the start of horizontal scanning is waveform-shaped by the pulse shaping circuit 13, and R,
This serves as a start trigger signal for driving the gate pulse generator 18 for gating the signals demodulated into G and B primary color signals. This gate pulse generator 18 outputs three pulses with a frequency corresponding to one set (triplet) of R, G, and B phosphors, with a phase difference of 120°.
Phase gate pulses are generated, and the R, G, and B3 primary color signals are gated by the gate circuit 19 using these pulses to become RGB time-series point sequential signals. This signal is amplified by the amplifier circuit 20 and applied to the electron gun.
The electron beam modulated by the RGB point sequential signal is R,
By reaching the positions of the G and B phosphors, a color image is projected.

In the above embodiment, the scanning speed of the beam is kept constant,
This is a method in which the RGB time series point sequential signal is converted into a time series at a certain time interval. The gate pulse for creating this RGB time series point sequential signal is generated using the index signal obtained from the index electrode at the start of horizontal scanning as a trigger, but various signal processing circuits are activated from the moment the electron beam scans the index electrode. There is a certain amount of time delay before the data is fed back to the electron gun, which prevents correct color reproduction.

The present invention aims to obtain faithful color reproduction images by making accurate phase correction, which is the drawback described above.One embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows the screen structure of the index type color picture tube used in the present invention, in which R, G, and B phosphor stripes 302R, 302G, and 302B are arranged on a face plate 306 via a black guard band 303. They are applied repeatedly perpendicularly to the horizontal scanning direction of the beam while adjoining each other, and only the black guard band 303 is applied outside the effective screen. A metal back electrode 304 is formed by vapor deposition on the phosphor stripes 302 and the black guard band 303, and an index phosphor 305 is further applied thereon.
This index phosphor 305 is not provided within the effective scanning screen, but is applied at the beam scanning position outside the effective screen, that is, at the top and bottom outside the effective screen, and at the start and end of horizontal scanning, and its pitch is Same as the triplet width of the color phosphor 302, or 1/
There is a relationship of 2 ⁿ (n: integer) times. Figure 3a shows the screen structure as seen from the beam scanning side, and Figure 3b shows B-
A sectional view of part B', and c a sectional view of part c-c'.

Other than the above screen structure, the structure is similar to that of a conventional index type color picture tube.

FIG. 4 shows the structure of the main circuit parts of a color TV receiver using the color picture tube described above. FIG. 5 shows signal waveforms to facilitate understanding of the operation of the circuit shown in FIG. 4.

First, a signal obtained by superimposing a white pulse 502 shown in FIG. 5 on a video signal is applied to the color picture tube 401 to modulate the electron beam. Here, the white pulse 502 is generated by a white pulse generator 408 based on the HD and VD signals, and the index phosphor formed at the top outside the effective screen is scanned with a certain DC beam to generate the index signal. A white pulse 503 for extracting the index signal and a white pulse 509 for extracting the index signal by scanning the index phosphor formed at the start and end portions of horizontal scanning outside the effective screen with a certain DC beam in the same manner. have.

First, the electron beam modulated by the white pulse 503 at the start of vertical scanning is shown in Fig. 3B.
The B' portion is scanned, and the photoelectric conversion element 402 receives the light emission 505 from the index phosphor 305, which is converted into an electrical signal. At this time, a certain time delay occurs from when the electron beam hits the index phosphor 305 (the current waveform of the beam incident on the phosphor is shown at 504) until it emits light, and this is defined as τ ₁ . After this signal is amplified by an amplifier 403, an index signal with a frequency corresponding to the index phosphor pitch is taken out from the BPF 404, a part of which is put into a memory circuit 405, and a part of which is put into a limiter circuit 406 for waveform shaping. The signal is input to the trigger pulse generation circuit 407. Here, photoelectric conversion element 4
The signal delay times from 02 to the output of the BPF 404 and the output of the limiter circuit 406 are τ ₂ and τ ₃ , and the respective signal waveforms are 506,
507, as shown. The start/trigger pulse generation circuit 407 generates a start/trigger pulse based on, for example, the third rising or falling edge of the rectangular wave input 507 after the start of horizontal scanning.
(FIG. 5 shows a start/trigger pulse waveform created based on the rising edge of 508.) This start/trigger pulse 508 causes the memory circuit 40 to
5 is activated, the index signal after the 506 waveform point in FIG. 5 is written into the memory circuit 5,
It is held for 1V. Control of writing and reading signals into the memory circuit 405 is controlled by determining a white pulse waveform, for example.

Next, during the subsequent horizontal scan, as mentioned above,
In order to scan the stripe-shaped index phosphor formed at the start and end of the horizontal scan outside the effective screen with a DC beam, the image signal with a white pulse 509 superimposed on the start and end of the horizontal scan is used to electronically scan. Modulate the beam. At this time, the electron beam current waveform to the index phosphor, the emission waveform from the index phosphor, the BPF signal output waveform, and the limiter signal output waveform at the start section are 510, 51.
1,512,513. It goes without saying that each delay time is the same as the delay time described above.

The start/trigger pulse 514 used to read out the above-mentioned written index signal from the memory circuit 405 is generated based on the second rising edge of the rectangular wave signal 513, which is the output of the limiter circuit 406, after the start of horizontal scanning. The memory circuit 405 is activated and its output 515 is obtained. Here, the start trigger pulse 51 at the time of reading
Where to generate 4 may be determined based on the following conditions. Now, if one cycle period of the index signal is T, and the signal delay time from reading the index signal from the memory circuit 405 to modulating the electron beam through the index signal processing circuit system described later is _τ4 , then T> If τ ₁ + τ ₂ + τ ₄ , start trigger pulse 5 during writing
A start trigger pulse is generated from the rise of the index signal one cycle before 08, or from the rise of the index signal two cycles before if T<τ ₁ +τ ₂ +τ ₄ <2T. By doing this, a negative delay time is given, and the phase shifter 40 next to the memory circuit 405
If the fine adjustment delay time τ ₅ τ ₅ =T−(τ ₁ +τ ₂ +τ ₄ ) is given in step 9, the total delay time of this index signal processing circuit system can be set to 0. That is, since phase compensation can be performed completely, a faithful color reproduction image can be obtained.
The state of the above delay time correction is shown in Fig. 5 515, 516.
Shown below. 515 is an index signal read from the memory circuit 405, and 516 is a signal waveform when input to the electron gun via the index signal processing circuit system after the phase shifter 409.

The index signal adjusted by the phase shifter 409 so that the delay time caused by the entire circuit system becomes completely zero is as follows.
Enter gate pulse generator 410. Here, by multiplying the frequency of the index signal by 2 ⁿ times, three-phase gate pulses having the same frequency as the triplet frequency of the phosphor but having a phase difference of 120° are generated, and this is input to the gate circuit 411 . This gate circuit 41
1, the TV demodulated into R, G, and B primary color signals.
Gating the signal and converting it to an RGB time series point sequential signal. The above-mentioned white pulse is superimposed on this point sequential signal in a mixer 412, and after being amplified in the next amplifier 413, the index color picture tube 40
1 and modulates the electron beam to project a color image.

As explained above, in order to improve the contrast and color purity of a reproduced image, the present invention does not provide an index signal generating section within the effective scanning screen, but only outside the effective scanning screen, and uses the direct current electron beam. In an index color receiver, an index signal with a good S/N ratio is obtained by scanning at By changing the phase (position) of the start/trigger pulse generation of the memory circuit control system from The present invention provides a beam index color TV receiver that displays color images.

[Brief explanation of the drawing]

Figure 1 shows a conventional index picture tube, a
is a sectional view thereof, b is a plan view of the face plate, and c is an enlarged view of the same portion. Fig. 2 is a block diagram showing the circuit configuration of a conventional color television receiver using this, and Fig. 3 shows the face plate of the index color picture tube used in the present invention, and a is a plane seen from the electron beam scanning side. In the figure, b is a cross-sectional view taken along line AA', and figure c is a cross-sectional view taken along line B-B'. FIG. 4 is a block diagram showing the circuit configuration of a color television receiver according to an embodiment of the present invention using this, and FIG. 5 is a signal waveform diagram illustrating its operation. 302R, 302B, 302G...Fluorescent stripe, 303...Black guard band, 304...Metal back electrode, 305...Index fluorescent material, 3
06...Face plate, 401...Color picture tube, 402...Photoelectric conversion element, 403...Amplifier, 4
04...BPF, 405...Memory circuit, 406...
Limiter circuit, 407...Start trigger pulse generation circuit, 408...White pulse generator,
409... Phase shifter, 410... Gate pulse generator,
411...Gate circuit, 412...Mixer, 413...
amplifier.

Claims (1)

[Claims] 1. Using a beam index color cathode ray tube having a striped index signal generating section at the upper or lower part of the face plate outside the effective scanning screen and at the start of horizontal scanning, The index signal generator is scanned with a constant DC beam, and the index signal obtained from this is used to start and scan.
A trigger pulse is generated, and based on this, an index signal during one horizontal scanning period is stored in a memory circuit, and this is held for one field period, and at every horizontal scanning period during an effective scanning screen period in the vertical direction. A start trigger pulse for reading is generated from an index signal obtained by scanning an index signal generator provided at the start of the horizontal scan outside the effective scanning screen, and based on this, an index signal is generated from the memory circuit. In a beam indexing color television receiver that reads out and uses this as the modulation control signal for the electron beam, the phase of the start/trigger pulse for starting the memory circuit when writing the index signal to the memory circuit differs from the memory circuit. A beam indexing color television set comprising a start/trigger circuit that compensates for a phase lag in an index signal by advancing the phase of a start/trigger pulse for activating a memory circuit when reading an index signal. Jiyoung receiver.