JPH0734356B2 - Driving method of flat plate color cathode ray tube - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method of a flat cathode ray tube used for a color television receiver, a terminal display of a computer and the like.

Configuration of Conventional Example and Problems There is a flat cathode ray tube as a prior art by the applicant of the present invention having a structure shown in FIG. Actually, a vacuum envelope (glass container) has a structure that incorporates each electrode.
In the figure, the vacuum envelope is omitted to clarify the internal electrodes. Further, in order to clarify the horizontal and vertical directions of the screen for displaying images, characters, etc., the face plate portion is shown in the horizontal direction (H) and the vertical direction (V).

First, a plurality of vertically long linear cathodes 10 each having an oxide formed on the surface of a tungsten wire are independently arranged in the horizontal direction at equal intervals. The number of the linear cathodes 10 and the intervals at which they are arranged are a matter of design. For example, assuming that the display screen size is 10 inches, the horizontal intervals at which they are arranged are about 10.
Twenty linear cathodes of 10 mm are arranged vertically with a length of about 160 mm. On the side opposite to the face plate portion 9 with the linear cathode 10 interposed therebetween, the linear cathode 10 is adjacent to the linear cathode 10 and is vertically divided at an equal pitch on the insulating support 11 and is electrically divided to be elongated in the horizontal direction. A vertical scanning electrode 12 is arranged.
These vertical scanning electrodes 12 are formed as independent electrodes equivalent to the number of horizontal scanning lines (about 480 in the NTSC system) in the vertical direction when displaying a normal television image. Next, from the side of the linear cathode 10 between the linear cathode 10 and the face plate 9, a planar electrode having an opening at a portion corresponding to the linear cathode 10 is sequentially divided between adjacent cathodes, A first grid electrode (hereinafter referred to as G1) 13 that applies a video signal to each planar electrode to perform beam modulation, and an opening similar to G1 electrode 13, and a second electrode that is not electrically divided in the horizontal direction. A grid electrode (hereinafter G2) 14 and a third grid electrode (hereinafter G3) 15 are arranged. Next, a fourth grid electrode (hereinafter referred to as G4) 16 having the same opening as the G2 electrode 14 or the G3 electrode 15 or having a wide opening in the horizontal direction is arranged. Next, the horizontal focus electrode 17 and the horizontal deflection electrode 18, which are formed on the surface of the insulating support 19 by plating or vapor deposition, are arranged symmetrically with respect to each electron beam linear axis and horizontally at the same interval as the cathode interval. Then, a light emitting layer composed of the phosphor 7 and the metal back electrode 8 is formed on the inner surface of the face plate 9. In color display, the phosphors are sequentially formed in the horizontal direction as red (R), green (G), and blue (B) stripes or dots.

Next, the operation of the color cathode ray tube will be described with reference to FIGS. In FIG. 2, a current is applied to the linear cathode 10 to heat it, and a voltage substantially equal to the potential of the cathode 10 is applied to the G1 electrode 13 and the vertical scanning electrode 12. At this time, a beam (100 to 300 V) higher than the potential of the cathode 10 is applied to the G2 electrode 14 so that the beam advances from the cathode 10 toward the G1 electrode 13 and the G2 electrode 14, and the beam passes through each electrode opening. To do. Here, in order to control the amount of the beam passing through the openings of the G1 and G2 electrodes, the voltage of the G1 electrode 13 is changed. The beam that passed through the aperture of G2 electrode 14
Go to G3 electrode 15 → G4 electrode 16 → horizontal focus electrode 17,
A predetermined voltage is applied to these electrodes so that the electron beam becomes a small spot on the phosphor screen. Here, the vertical beam focus is performed by the electrostatic lens formed at the exit of the aperture of the G4 electrode 16, and the horizontal beam focus is the electrostatic focus formed between the horizontal focus electrode 17 and the horizontal deflection electrode 18. Done with a lens. The beam that has passed through the horizontal focus electrode 17 is deflected to the horizontal deflection electrode 18 through the buses 18a and 18b in the horizontal direction by the deflection voltage of the sawtooth wave or the staircase wave having the horizontal scanning period and has a predetermined width to stimulate the phosphor 7. Obtain a luminescent image. To obtain a color image, when each electron beam horizontally scans the phosphor 7 as described above, a modulation signal of a color corresponding to each phosphor on which the electron beam is incident is generated.
It is applied to the G1 electrode 13.

Next, vertical scanning will be described with reference to FIG. As described above, the electric potential of the space surrounding the linear cathode 10 is controlled from the linear cathode 10 by controlling the voltage of the vertical scanning electrode 12 so that the electric potential is positive or negative than the electric potential of the linear cathode 10. The generation of electrons is controlled. At this time, if the distance between the linear cathode 10 and the vertical scanning electrode 12 is small, the voltage for controlling ON / OFF of the beam from the cathode may be small. In the vertical scanning electrode 12, when the interlace method is minimized, in the first 1st field, the beam is generated (hereinafter, ON) signal from the vertical scanning electrode 12A for only one horizontal scanning period (hereinafter, 1H). During 1H, the signal that the beam is turned on at 12C will be sequentially output every other vertical scanning electrode.
A signal that turns the beam ON is applied only during 1H, and
When 12X is completed, the vertical scanning of the first field is completed. In the next second field, a signal for turning on the beam only during 1H is similarly applied from 12B, and one frame of vertical scanning is finally completed by scanning up to 12Y.

When a faithful color image is displayed in a flat-plate cathode ray tube that displays a full color screen by the above vertical scanning, beam modulation, and horizontal scanning, it corresponds to the color phosphor into which the electron beam is incident. The color modulation signal should be applied to the G1 electrode, but this cathode ray tube does not have that function and the hue changes when the horizontal deflection width changes,
Further, in manufacturing this cathode ray tube, if the intervals between the horizontal deflection electrodes are not uniform, a color image having different hues is obtained in each horizontal block.

An object of the present invention is to provide a method of driving a cathode ray tube capable of detecting a beam arrival position on a phosphor screen for each cathode block and displaying a faithful color image.

According to the present invention, an effective screen display area in which at least three primary color phosphors of red, green and blue are repeatedly arranged horizontally in a horizontal direction through a black area, and the three primary color phosphors are adjacent to each other on the outer side in the vertical direction. The same as the inter-pitch, and has an index phosphor screen region provided with an index phosphor group that emits an index signal excited by electron beam scanning at a position corresponding to the position of the black region of the effective screen display region, Along with horizontally arranging a plurality of electron sources composed of vertically long linear cathodes separated corresponding to each of the index phosphor screen region and the effective screen display region,
A horizontal deflection electrode for horizontally deflecting each electron beam is arranged for each linear cathode, and when scanning the index phosphor group, the electron beam is modulated by a signal having a frequency sufficiently higher than the frequency of the index signal for scanning. The present invention provides a method for driving a flat panel color cathode-ray tube that displays a color image by alternately repeating a region to be scanned and a region in which the index phosphor group is always scanned with a constant DC beam to detect an index signal. .

Description of Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 4 is an external view of one embodiment of the present invention, FIG. 5 shows the details of the electrode structure having the structure shown in FIG. 4, and FIG. 6 shows the details of the fluorescent screen having the structure shown in FIG. In the effective screen display area (A in Figure 4)
The R, G, and B phosphor stripes 40R, 40G, and 40B of the respective colors are sequentially and repeatedly formed in the horizontal direction via the black stripes 41 of the non-luminescent material. On the other hand, the index phosphors 42 are horizontally formed at the same pitch as the color phosphor pitches via the black stripes 41 on the outer side in the vertical direction of the effective screen display area (portion B in FIG. 4). The effective screen display area is the same as in the conventional example of FIG. 1 and its description is omitted. However, outside the effective screen display area, as shown in FIG. 5, the linear cathode 50-b and the electrode 52 on the back surface thereof are shown. The -b and G1 electrode 53-b are separated from the linear cathode 50-a, the back electrode, that is, the vertical scanning electrode 52-a and the G1 electrode 53-a in the effective screen display area, respectively. Other electrodes, that is, G2 electrode 54, G3 electrode 55, G4 electrode 56,
The horizontal focus electrode 57 and the horizontal deflection electrode 58 are common.
FIG. 6 is a detailed view of the phosphor screen described in FIG. FIG. 6A is a front view or a rear view of FIG. 4, and FIG. 6B is a sectional view taken along the line CC ′ of FIG. 6A. Here, the index phosphor 42 is formed at a position corresponding to the position of the black stripe 41 in the effective screen. As the index phosphor 42, it is preferable to use a phosphor that emits light having a wavelength other than the emission wavelengths of the R, G, and B phosphors. Photoelectric conversion elements 46a, 46b ... Are arranged for each cathode block (a, b, ...) Through an optical filter 45 that passes only index light outside the face plate 44 corresponding to the index phosphor portion. .

The operation of only the index portion of the above horizontal color cathode ray tube will be described. (The operation within the effective screen is the same as that of the conventional example described in FIG. 1 and therefore omitted.) Back electrode 52
-B is an index fluorescent substance 52 because a DC voltage of approximately the same potential as the cathode potential is constantly applied so that a beam is always generated from the cathode 50-b toward the G1 electrode 53-b.
In the effective screen display area, the beam is always scanned while the beam is vertically deflected while being vertically scanned. However, in FIG. 6, assuming that the index phosphors 42 are the same across the cathode blocks, the light emitted by the adjacent beams enters the respective photoelectric conversion elements 46, so that the index signal indicating the accurate beam position can be obtained. Absent.
In order to eliminate the influence between the adjacent beams, in the cathode block a, the beam is modulated by a signal having a frequency sufficiently higher than the index scanning frequency of the beam and the index frequency which can be formed by the repeating pitch of the index phosphor, and the beam of the cathode block b does not exist. Modulation, and therefore a constant DC voltage is applied to the G1 electrode 53-b, and the index signals from the respective beams are electrically frequency separated as described later, so that the correct index signal is obtained for each beam.

Next, before describing a method of driving a color image display by the flat plate color cathode ray tube, a signal processing system for television image display using a cathode ray tube having a large number of beam sources in the horizontal direction as in the present invention. , FIG. 7 and FIG.

Timing pulse generator 74 based on TV sync signal 72
A timing pulse for driving a circuit block described later is generated. First, with one of the timing pulses,
The demodulated R, G, B three primary color signals (E _R , E _G , E _B ) 71 are converted into digital signals by the A / D converter 73, and the 1H signal is input to the first line memory circuit 75. To do. When all 1H signals are input, the signals are input to the second line memory circuit.
The signals of the next 1H are simultaneously transferred to 76, and are input to the first line memory circuit 75 again. The signal transferred to the second line memory circuit 76 is stored and held for 1H and also sent to the D / A converter (or pulse width converter) 77, where the original analog signal (or pulse width modulation) is used. Signal), amplified and applied to the modulation electrode (G1) of the cathode ray tube. Such a line memory circuit is used for time axis conversion, and its detailed description will be given with reference to FIG.

Let n be the number of beams (that is, the number of cathodes) used for scanning the effective screen area, and 2 triplets (one triplet is one set of R, G, B phosphor stripes) where each beam horizontally scans. , R between 1H, G, B
The video signal insertion time T of each primary color signal 81 is divided into T / n, the time axis of the video signal of each period is multiplied by n to obtain T, and the arrangement of the fluorescent stripes on the fluorescent surface is R → G. → If it is B, each primary color signal multiplied by n and extended to T time is T / 6
It is gated with a gate pulse having a time width, converted into a time series signal 82 of E _R → E _G → E _B , and input to a predetermined G1 electrode.
In this way, an image of 1H is formed, and the entire image is formed in cooperation with the vertical scanning.

Here, it is necessary to set the timing between the time series color signal applied to the G1 electrode and the phosphor screen scanning position of the electron beam. That is, when the electron beam reaches the R phosphor, the beam must be modulated by the R signal. The signal processing for this will be performed with reference to FIGS. 9 and 10.

As described above, the fundamental frequency of the index signal, which is determined by the beam scanning speed and the repetition pitch of the index phosphor, is _i . Frequency _{S that} is sufficiently higher than _i
When the signal from the oscillator 90 of No. 1 is amplified by the amplifier 91 and applied to a, c, e of the index signal generator G1 electrode every other horizontal direction, the index signal (E _Ia ) 92 from this part is applied. Is E _Ia = E _i · E _S cos (2π _S · t + _S ). (E _i ; index signal obtained when the index phosphor is scanned with a DC beam) This is ( _S + _i ) by a bandpass filter (hereinafter BPF) 93, or ( _S
When the frequency component of _−i ) is extracted, its output is (tenth
93 ′) E _i ′ E _S cos {2π _S + _i ) · t + ( _S + _i )}. ( _S , _i is the output of the high frequency oscillator and the phase of the index signal) When this is multiplied by the signal from the high frequency oscillator 90 in the following calculator 94, E [cos (2π _i t + _i ) + cos {2π (2 _S +
_i ) t + (2 _S + _i )}], and if the low frequency component of the first term is taken out to the BPF95 of the next stage, the signal of the fundamental frequency component of the same index signal as when scanning with the DC beam can be obtained. become. (No.
This is shaped by the limiter 96 at the next stage, and the output (Fig. 96 ') is generated by the three-phase pulse generators 97 and 3.
It is sent to the phase pulse generator control circuit 98. The limiter 96 also includes a delay circuit for associating the phosphor position with the color signal. The television sync signal 100 is also input to the control circuit 98,
0 Generate the signal of FIG. 98 '. That is, a reset signal for the three-phase pulse generator 97 is generated from the horizontal synchronizing signal of the television, and at the same time, a pulse counter (not shown) included in the three-phase pulse generator control circuit 98 is activated based on the reset signal, Here, in the example of FIG. 10, seven pulses are counted at the rising edge of the pulse, and the reset signal is made "O" at the output thereof to stop the operation of the three-phase pulse generator 97. It goes without saying that a pulse counter output may be used as the three-phase pulse generator control signal 98 '. The three-phase pulse generator 97 divides the input signal (Fig. 96 'in Fig. 10) by 1/3 to generate three-phase pulses (first phase difference of 120 °).
0'97'R, 97'G, 97'B) are produced, and these pulses gate the respective primary color signals of the D / A converter output explained in FIGS. 7 and 8 with the gate circuit 99, E _R ′ → E _G ′
→ Obtain the time series signal of E _B ′. Alternatively, the time series signal may be obtained by using the three-phase pulse 97 'as a read timing pulse from the second line memory 76. By amplifying this gate output signal and applying it to each modulation electrode, it is possible to set accurate timing between the arrival position of the electron beam on the phosphor screen and the color signal, and display a faithful color image.

On the other hand, a constant DC voltage is applied to the modulation electrodes b, d, ... Adjacent to the modulation electrodes a, c, e ... Of the cathode ray tube, and the index phosphor screen is scanned with an unmodulated beam. When the index signal 101 obtained from the above is passed through the BPF 102 which extracts only its fundamental frequency component, a signal similar to the output of the BPF 95 shown in FIG. Therefore, the subsequent signal processing may be performed in the same manner as the index signal processing, and a description thereof will be omitted.

As described above, the index generator is provided outside the effective display screen in the vertical direction, and the index signal is always detected for each cathode block from this, and the beam modulation signal in the effective screen is controlled based on this. To obtain a faithful color image.

In the example described above, the G1 electrodes of the index phosphor screen were connected to every other cathode block and signals of different frequencies were applied.
It goes without saying that 1) every other line (n ≧ 2) may be commonly connected and beam modulation may be performed with signals of different frequencies.

FIG. 11 shows another embodiment of the present invention. That is, the index signal generators B and C are provided above and below the effective screen area A, and are divided into upper and lower portions for each adjacent cathode block. Correspondingly, it goes without saying that the back electrode 52-B, the linear cathode 50-b, the G1 electrode 53-b and the photoelectric conversion parts 45 and 46 described in FIG. In the cathode ray tube having such a structure, it is possible to prevent the mixing of the index signal from between the adjacent cathode blocks as in the first embodiment. Therefore, the beam for scanning the index fluorescent screen may be an unmodulated beam. Since the index signal processing can be easily considered from the first embodiment, the description will be omitted.

As described above, according to the present invention, an index signal generating section for detecting the beam position on the phosphor screen is provided on the outer side in the vertical direction of the effective display screen for each cathode block, and the index signal generating section constantly outputs the index signal. Is generated and detected for each cathode block, and by controlling the beam modulation signal within the effective screen based on this index signal, mechanical for each cathode block,
Alternatively, it is possible to obtain a faithful color reproduction image by absorbing an electrically generated horizontal deflection width, variations in the beam arrival position on the phosphor screen, and the like.

[Brief description of drawings]

1 to 3 show a conventional example of a flat plate type color cathode ray tube, FIG. 1 is a partial perspective view thereof, FIG. 2 is a horizontal sectional view, and FIG. 3 is a vertical scanning operation explanatory view. FIG. 4 is an external view of a flat plate color cathode ray tube according to the present invention, FIG.
FIG. 6 is a vertical sectional view thereof, FIGS. 6 (A) and 6 (B) are front views and sectional views of the phosphor screen portion, FIG. 7 is a block diagram showing a signal processing system, and FIG. 8 is its operation waveform diagram. FIG. 9 is a block diagram showing an index signal processing system, FIG. 10 is an output signal waveform diagram of each part thereof, and FIG. 11 is a phosphor screen structure diagram of a flat plate type color cathode ray tube according to another embodiment of the present invention. 10,50 …… Linear cathode, 12,52-a …… Vertical scanning electrode,
52-b …… Back electrode, 13,53 …… G1 electrode, 14,54 …… G2 electrode, 15,55 …… G3 electrode, 16,56 …… G4 electrode, 17,57 …… Horizontal focus electrode, 18 , 58 …… Horizontal deflection electrode, 9,44 ……
Face plate, 7,47 ... Phosphor screen, 8,43 ... Metal back electrode, 40 ... R, G, B color phosphor stripe, 41 ... Black stripe, 42 ... Index phosphor, 45 ...
Optical filter, 46 …… Photoelectric conversion element, 71 …… 3 primary color signals, 72,100 …… TV sync signal, 73 …… A / D converter, 74 …… Timing pulse generator, 75,76 …… Line memory, 77… … D / A converter, 90 …… High frequency oscillator, 91 …… Amplifier, 92,101 …… Index signal input,
93,95,102 …… BPF, 94 …… Multiplier, 96,103 …… Limiter, 97 …… 3-phase pulse generator, 98 …… 3-phase pulse generator control circuit, 99 …… Gate circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshikazu Kawauchi, 3-10-1, Higashisanda, Tama-ku, Kawasaki City, Kanagawa Prefecture Matsushita Giken Co., Ltd. No. 10 No. 1 Matsushita Giken Co., Ltd. (56) References JP-A-59-119659 (JP, A) JP-A-53-72523 (JP, A)

Claims (1)

[Claims] 1. An effective screen display area in which at least three primary color phosphors of red, green, and blue are repeatedly arranged in a horizontal direction through a black area, and an adjacent pitch of the three primary color phosphors on the outer side in the vertical direction. The same, and having an index phosphor screen region provided with an index phosphor group that emits an index signal is excited by electron beam scanning at a position corresponding to the position of the black region of the effective screen display region,
While arranging a plurality of electron sources in the horizontal direction, each of which is composed of a linear cathode that is long in the vertical direction and is separated corresponding to each of the index phosphor screen region and the effective screen display region,
A horizontal deflection electrode for horizontally deflecting each electron beam is arranged for each linear cathode, and when scanning the index phosphor group, the electron beam is modulated by a signal having a frequency sufficiently higher than the frequency of the index signal for scanning. A method for driving a flat-plate color cathode-ray tube, characterized in that the index signal is detected by alternately repeating a region for scanning and a region for always scanning the index phosphor group with a constant DC beam.