JPS6310895A - Color picture display device - Google Patents

Abstract

PURPOSE:To obtain a color picture without color smear, by following the fluctuation of deflection amplitude in a horizontal scan by an index signal, and controlling a timing with which a chrominance signal is impressed. CONSTITUTION:A control data from an A/D converter 58 is added on a refer ence frequency division ratio at an adder 75, and becomes the preset value of a frequency division counter 74. Thereby, the frequency of a clock signal generated from a clock generator 70 changes by the output value of the A/D converter 58. Therefore, at the the of counting the value stored in advance in a memory 60 by a counter 61, the timings t1, t2,... with which a measured value, that is, the chrominance signal is impressed, change corresponding to the frequency value of the clock signal, and it is possible to coincide the incident timing of a beam on a color fluorescent body, with the timing with which the chrominance signal is impressed, following the fluctuation of the deflection amplitude in the horizontal scan.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a flat cathode ray tube used in color television receivers, computer terminal displays, etc.

2. Description of the Related Art As a prior art planar cathode ray tube created by the present applicant, there is a structure shown in FIG. In reality, each electrode is housed in a vacuum envelope (glass container), but
In the figure, the vacuum envelope is omitted to make the internal electrodes clear. In addition, to clarify the horizontal and vertical directions of the screen on which images, characters, etc. are displayed, the horizontal direction (H) and vertical direction (V) are shown on the face plate.

Reference numeral 10 denotes a plurality of linear cathodes, which are long in the V direction and are formed by coating the surface of a tungsten wire with an oxide cathode material, and are arranged independently at equal intervals in the horizontal direction. Linear cathode 10
On the opposite side of the face plate portion 2B, vertical scanning electrodes 12 are arranged on the insulating support 11 in the vicinity of the linear cathode 1o, at equal pitches in the vertical direction, and electrically divided and elongated in the horizontal direction. Placed. These vertical scanning electrodes 1
2 is formed as an independent electrode A having the number of horizontal scanning lines in the vertical direction (approximately 480 in the case of the NTSC system) if a normal television image is to be displayed. Next, between the linear cathode 10 and the face plate portion 28, linear cathodes 10. A first grid electrode that divides a planar electrode having an opening in a portion corresponding to the vertical scanning electrode 12 between adjacent linear cathodes 10, and performs beam modulation by applying all video signals to each electrode. (hereinafter referred to as G1) 13, a second grid electrode (hereinafter referred to as G2) 14 which has the same opening as the G1 electrode 13 and is not divided horizontally, and a third grid electrode (hereinafter referred to as G5) 1s
Place. The G2 electrode 14 is for generating an electron beam from the linear cathode 10, and the G3 electrode 16 is for shielding the electric field from the subsequent electrode and the beam generating electric field.
The video signal may be applied to the linear cathode 10, in which case there is no need to split the G+ electrode 13. Next, a fourth grid electrode (hereinafter referred to as G) 16 is arranged, and its opening is larger in the horizontal direction than in the vertical direction. FIG. 7(A) shows the horizontal cross-section of the metal shown in FIG. 6, and FIG. 7(B) shows the vertical cross-section.

At the rear of the G4 electrode 16, two electrodes 17 and 18'ii having apertures that are sufficiently wider in the horizontal direction than in the vertical direction, similar to the apertures in the G4 electrode 16, are arranged, as shown in Fig. 7 (Bl). A vertical deflection electrode is formed by shifting the aperture center axes of the two electrodes in the vertical direction.Vertical deflection electrode 1711
8, a plurality of vertically long electrodes are provided between the linear power nodes 10 toward the face plate portion 28 side. FIG. 6 shows the case of three stages as an example, and each electrode is a first horizontal deflection electrode (hereinafter referred to as DH-1) 19,
A second horizontal deflection electrode (hereinafter referred to as DH-2) 20 degrees, a third horizontal deflection electrode (hereinafter referred to as DH-3) 21, and each horizontal deflection electrode 19 to
21 is a common bus bar 22, 23, 24 every other line in the horizontal direction
It is connected to the.

The same voltage as the DC voltage applied to the metal back electrode 26 of the face plate section 28 is applied to the DH-3 electrode 21, and the voltage for horizontal focusing of the beam is applied to the DH-1 electrode 191 and the DH-2 electrode 20. applied. A light emitting layer consisting of a fluorescent surface 27 and a metal bank electrode 26 is formed on the inner surface of the face plate portion 28 . When displaying in color, the fluorescent surface sequentially displays light (R), green (G), and blue (light) in the horizontal direction.
B) The phosphor stripes are formed through a black guard band.

Next, the operation of the color cathode ray tube will be explained. heating the linear cathode 10 by passing an electric current through it;
G1 electrode 13. A voltage approximately the same as the potential of the cathode 10 is applied to the vertical scanning electrode 12 . At this time, the beam advances from the cathode 10 toward the G1102 electrode (13, 14), and the cathode 10 is moved so that the beam passes through each electrode aperture.
When applying a voltage that is higher than the potential of
2 electrodes 14. Here, the amount of the beam passing through each aperture of the GI02 K pole is controlled by changing the voltage of the G1 electrode 13 or the linear cathode 1o. The beam that has completely passed through the aperture of G2 electrode 14 is transferred to G5 electrode 1.
6→G4 electrode 16→vertical deflection electrode 17.18→horizontal deflection electrode 19. 20. Proceeding to step 21, a predetermined voltage is applied to these electrodes so that the electron beam forms a small spot on the fluorescent surface 26. Here, the beam focus in the vertical direction is determined by the G3 electrode &161 G4 electrode 16. carried out with an electrostatic lens formed between vertical deflection electrodes 17, 18,
Horizontal beam focus is DH-1°DH-2,D
This is done with an electrostatic lens formed between each of H-3. The two electrostatic lenses are formed only in the vertical and horizontal directions, respectively, so that the vertical and horizontal spot sizes of the beam can be adjusted individually.

Also DH-1 (19), DI-2 (20).

Bus bar 22, 2392 connected to DH-3 (21)
4 is applied with a sawtooth wave, triangular wave, or staircase wave deflection voltage with the same voltage and horizontal scanning period, deflecting the electron beam in the horizontal direction by a predetermined width, and scanning the fluorescent surface 26 with the electron beam. Obtain luminescence @.

Next, vertical scanning will be explained using FIG. 8.

As described above, by controlling the voltage of the vertical scanning electrode 12 so that the potential of the space surrounding the linear cathode 10 is more positive or negative than the potential of the linear cathode 1o, the linear cathode 10 The generation of electrons from is controlled. At this time, if the distance between the linear cathode 10 and the vertical scanning electrode 12 is small, a beam is generated from the cathode (hereinafter referred to as O
N), the voltage for controlling shutoff (OFF) may be small.

In the case of the current television system that uses an interlaced system, a predetermined deflection voltage tl-1 field is applied to the vertical deflection electrode 18119 in the first field, and one horizontal scanning voltage is applied to 12A of the vertical scanning electrode 12. The beam modulation electrode is applied only during the period (hereinafter referred to as 1H), and the beam modulation electrode is applied to the other vertical scanning electrodes (12B to 12Z).

After 1H has elapsed, a beam ON voltage for 1H is applied only to the vertical scanning electrode 12B, and then a voltage is applied to the vertical scanning electrode to turn the beam ON only for 1H, and when 122 at the bottom of the screen ends, the voltage for the first 1 field is applied to the vertical scanning electrode 12B. Vertical scan is completed. In the next second field, the polarity of the deflection voltage applied to the vertical deflection electrodes 17 and 18 is reversed, and this is applied for one field.

The signal voltage applied to the vertical scanning electrode 12 is applied in the same manner as in the first field. At this time, the vertical deflection electrode 17.
The amplitude of the deflection voltage applied to 18 is adjusted. As described above, the vertical scanning electrode 12 has the first. The same vertical scanning signal voltage is applied to the second field, and the vertical deflection electrode 17
By changing the deflection voltage applied to the angle 18 between the first field and the second field, one frame of vertical scanning is completed.

Next, in a cathode ray tube having a plurality of beam generation sources in the horizontal direction, such as the flat cathode ray tube described above, there is a beam index method as a method of applying a video signal to a beam modulation electrode. The applicant has previously proposed this beam index method, which will be briefly explained using FIGS. 9, 10, and 11.

FIG. 10 is a sectional view illustrating the relative application positions of the primary color phosphors 42 and the index phosphors 4° on the phosphor surface 27 of the flat cathode ray tube. Index phosphor 40
is outside the image display area, and its repetition pitch may be equal to or different from the repetition pitch of the primary color phosphors 42. The index phosphor 4o and the primary color phosphor 42 are scanned by mutually synchronized beams and emit light, respectively. These light emissions are converted into electrical signals by a photoelectric conversion element, and finally an index signal (I) and, for example, a blue signal (B) shown in FIG. 11 are obtained. Then, the phase difference between the two signals is determined by counting the clock signal with the measurement counter 31 shown in FIG.
2s ts... is measured and stored in the memory 32. This operation is performed in advance for all scanning lines, and when actually displaying the entire image, the counter 33 counts down the clock signal according to the value stored in the memory 32 using the index signal as a reference,
The timing is set to apply each color signal to the beam modulation electrode. This makes it possible to match the timing at which the beam enters each primary color phosphor with the timing at which each color signal is applied, and an image without color shift can be obtained.

Problems to be Solved by the Invention As shown in FIG. 6, the flat cathode ray tube described above is composed of blocks divided horizontally by the number of linear cathodes 10. When displaying an image on the fluorescent surface 27, the display areas of each block are joined to form one image r.
elephant is displayed. Therefore, the beams that horizontally scan each block will not overlap or separate from each other at this joint, and will impact a determined position at a determined timing.
It is necessary to do 6.

As described above, the application timing of each color signal is stored in advance with reference to the index signal.

Therefore, if the deflection speed changes due to amplitude fluctuations in the horizontal deflection waveform, etc., there will be a lag between the timing of applying each color signal according to the stored value and the impact position of the beam, resulting in faithful color reproduction. It disappears.

Means for Solving the Problems In the present invention, fluctuations in the horizontal deflection amplitude are detected using an index signal obtained from an index area provided outside the image display area of a flat cathode ray tube, and the clock signal is adjusted according to the detected value. The frequency is controlled to control the timing at which the color signal is applied to the beam modulation electrode.

Alternatively, the timing at which the color signal is applied to the beam modulation electrode is controlled by correcting the detected value by adding or subtracting a value previously stored in the memory.

Effect: With the above means, even if the horizontal deflection amplitude fluctuates, it is possible to correct the time value stored in the memory in advance accordingly, so that the beam is always aligned with each color band member ft.
The timing of the impact and the timing of applying the color signal to the beam modulation electrode can be matched.

Embodiment FIG. 1 shows a block diagram of main parts of a color image display device according to a first embodiment of the present invention, FIG. 2 shows a detailed block diagram of the clock generator 70 in FIG. 1, and FIG. Figure 3 shows the waveform diagram of each part.

In FIG. 1, light emitted from the index phosphor is converted into an electrical signal by a photoelectric conversion element 60, and amplified by an amplifier 61. The waveform shaping circuit 52 is composed of a filter, a limiter, etc., and shapes the output of the amplifier 61 into a rectangular wave index signal (1L) shown in FIG.

This index signal (&) is guided to the gate circuit 63, and is converted into the first index start pulse (1)) by a gate pulse (not shown) generated based on the horizontal drive pulse () ID)e. only is extracted. This pulse (b) resets the counter 54, and the counter starts counting the index signal (λ). Then, the D flip-flop 65 is reset by the index end pulse (C) which is output at the time when the count up to the final pulse of the index signal (ia) is finished. The power supply voltage +VCC is constantly applied as the D input to the D flip-flop 66, and the Q output, which was previously in a High state due to the index start pulse (b), is changed to the high state at the index end pulse (C). Returned to Low state. Therefore, the pulse width of the output pulse (d) of the D flip-flop 56 corresponds to the deflection amplitude of the horizontal scanning of the electron beam. When this pulse (d) is integrated by the integrating circuit 56, a sawtooth wave (
6) is obtained, the index end pulse (C
), the sample and hold circuit 57 samples and holds the signal. The held signal (f) is converted into a digital value by the A/D converter 58 during the immediately following horizontal blanking period, and is converted to a digital value by the clock generator 70.
as control data.

As shown in FIG. 3, the clock generator To includes a phase comparator 71, a low-pass filter 72, a voltage-controlled oscillator 73,
It is composed of a PLL circuit consisting of a frequency division counter 74, and further includes an adder 75 and a reference frequency division ratio setting circuit 76.

The control data from the A/D converter 58 is sent to the adder 75.
It is added to the reference frequency division ratio and becomes the preset value of the frequency division counter 74. As a result, the frequency of the clock signal generated by the clock generator 7o changes depending on the output value of the A/D converter 58.

Therefore, when counting the values stored in advance in the memory 60 with the counter 61, the timings t, , t2, t3, . ... changes,
It is possible to match the timing of the beam's incidence on the color band light body and the timing of applying the color signal by following the fluctuation of the deflection amplitude in horizontal scanning.

Next, FIGS. 2 and 4 regarding the second embodiment.

This will be explained using FIG. FIG. 2 differs from FIG. 1 in that the output of the A/D converter 58 is used to correct the data stored in the memory 8Q. Since the steps up to the output of the ρ converter 58 are the same as those in the first embodiment, the explanation will be omitted.

Fig. 4 shows a detailed diagram of Memo 1J80, which has a memory 81 for storing pre-measured data and a 1H memory 84, and is equipped with a data transfer pulse generation circuit 82 and an adder 83. .

The control data from the system/D converter 68 is added as correction data by an adder 83 when the data is transferred from the memory 81 to the 1H memory 84 during the horizontal blanking period. Then, this corrected measurement value is sent to the counter 61.
and is counted down by a clock signal. Therefore, the timing i1 Hi2 of applying the color signal
+i5...changes in accordance with the output data of the human/D converter 68, that is, fluctuations in the horizontal scanning deflection amplitude, and applies the timing of the beam's incidence on the color band light body and the color signal. You can match the timing.

Effects of the Invention As described above, the color image display device of the present invention can display color without color shift by controlling the timing of applying color signals by following fluctuations in deflection amplitude in horizontal scanning using an index signal. You can get the image.

[Brief explanation of the drawing]

1 and 2 are main part configuration diagrams of a color image display device according to the first and second embodiments of the present invention, and FIGS.
The figure is a block diagram for explaining details of FIGS. 1 and 2, FIG. 5 is a diagram showing operating waveforms of a color image display device in an embodiment of the present invention, and FIG. 6 is a diagram showing a conventional flat cathode ray. A perspective view of the tube, Figures 7(A) and [F]) are horizontal and vertical sectional views of the device, Figures 8(A) and (B) are illustrations of the same vertical scanning, and Figure 9 is a flat cathode ray. Fig. 10 is a cross-sectional view showing the relative application positions of the primary color phosphor and index phosphor of the tube, and Fig. 11 is a diagram explaining the operation of the tube. FIG. 4 is a signal waveform diagram. 10... Linear cathode, 12... Vertical scanning electrode, 13... G, electrode, 14...
...G2 electrode, 16...G3 electrode, 16...
...G4 electrode, 1, 18...Vertical deflection electrode, 19,20.21...Horizontal deflection electrode, 27.
...Fluorescent screen, 5o...Photoelectric conversion element, 5
8...M/D converter, 61...Counter, 70...Clock generation circuit, 74...
...Division counter, 75.83...Adder, 81...Memory, 84...1H memory. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure Clock Figure 4 Figure 5 (α] ``To Plate-l Knee Plate-JUIILJIII-cb (el If) ~ To Arrogant ~ ~ Figure 7/2C 2Y 2r

Claims (3)

[Claims] (1) An image display area provided with a fluorescent surface in which at least three primary color phosphors of red, green, and blue are arranged in sequence in a horizontal direction with a black area interposed therebetween, and an index phosphor outside the image display area. It has an image display element provided with an index area coated with a light substance, the index area is scanned in synchronization with an electron beam that constantly scans the image display area, and an index signal obtained from the index area is used. 1. A color image display device, characterized in that a variation in horizontal deflection amplitude is detected using the detection signal, and the timing of applying a color signal to a beam modulation electrode is controlled based on the detection signal. (2) A color image display according to claim 1, characterized in that the detection signal controls the frequency of a clock signal of a counter that generates the timing for applying the color signal to the beam modulation electrode. Device. (3) The color image display device according to claim 1, wherein the detection signal controls timing data for applying the color signal stored in the memory in advance to the beam modulation electrode. .