JPH0337793B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for driving a flat cathode ray tube used in color television receivers, computer terminal displays, and the like.

Conventional Structure and Problems There is a prior art flat cathode ray tube created by the present applicant with a structure shown in FIG. In reality, each electrode is housed in a vacuum envelope (glass container), but the vacuum envelope is omitted in the figure to make the internal electrodes clear. Further, in order to clarify the horizontal and vertical directions of the screen on which images, characters, etc. are displayed, a horizontal direction H and a vertical direction V are illustrated on the face plate portion.

First, a plurality of vertically long linear cathodes 10 each having an oxide formed on the surface of a tungsten wire are independently arranged at equal intervals in the horizontal direction. The number of linear cathodes 10 and the spacing between them are arbitrary. For example, if the display screen size is 10, the horizontal spacing between the 20 linear cathodes 10 is approximately 10 mm, and the 20 linear cathodes are vertically spaced approximately 10 mm apart. Arranged with a length of 160mm. On the opposite side of the face plate portion 9 across the linear cathode 10, there are strips arranged vertically at equal pitches on the insulating support 11 in close proximity to the linear cathode 10, and electrically divided and elongated in the horizontal direction. Vertical scanning electrodes 12 are arranged. These vertical scanning electrodes 12 are formed as independent electrodes having the same number of horizontal scanning lines in the vertical direction (approximately 480 in the NTSC system) if a normal television image is to be displayed. Next, between the linear cathode 10 and the face plate 9, from the linear cathode 10 side, planar electrodes each having an opening in a portion corresponding to the linear cathode 10 are sequentially divided between adjacent cathodes.
A first grid electrode (hereinafter referred to as G1) 13 that performs beam modulation by applying a video signal to each of the electrodes, a second grid electrode that has the same opening as the G1 electrode 13 and is not electrically divided in the horizontal direction. Electrode (hereinafter referred to as G2)
14. Place the third grid electrode (hereinafter referred to as G3) 15. Next, a fourth grid electrode (hereinafter referred to as G4) 16 having an opening that is the same as or wider in the horizontal direction than the openings of the G2 electrode 14 and the G3 electrode 15 is arranged. Next, horizontal focus electrodes 17 and horizontal polarization electrodes 18, which are formed by plating or vapor deposition on the surface of the insulating support 19, are arranged symmetrically with respect to each electron beam rectilinear axis and at the same spacing as the cathode spacing in the horizontal direction.
A light emitting layer consisting of a phosphor 7 and a metal pack electrode 8 is formed on the inner surface of the face plate 9.
For color display, the phosphors are formed as stripes or dots of red R, green G, and blue B sequentially in the horizontal direction.

Next, we will discuss the operation of the color cathode ray tube mentioned above.
This will be explained using FIG. Linear cathode 10
This is heated by passing a current through it, and a voltage substantially the same as the potential of the cathode 10 is applied to the G1 electrode 13 and the vertical scanning electrode 12. At this time, the beam advances from the cathode 10 toward the G1 and G2 electrodes 13 and 14, and a voltage higher than the potential of the cathode 10 (100 to 300 V) is applied so that the beam passes through each electrode aperture.
is applied to the G2 electrode 14. Here the beam is G1,
To control the amount that passes through each aperture in the G2 electrode,
This is done by changing the voltage of the G1 electrode 13.
The beam passing through the aperture of G2 electrode 14 is connected to G3 electrode 1.
5→G4 electrode 16→horizontal focus electrode 17, and a predetermined voltage is applied to these electrodes so that the electron beam forms a small spot on the fluorescent screen. Here, the vertical beam focus is performed by an electrostatic lens formed at the exit of the aperture of the G4 electrode 16, and the horizontal beam focus is formed between the horizontal focus electrode 17 and the horizontal deflection electrode 18. It is done with an electrostatic lens. The beam that has passed through the horizontal focus electrode 17 is deflected by a predetermined width in the horizontal direction by a sawtooth wave or staircase wave deflection voltage with a horizontal scanning period to the horizontal deflection electrode 18.
to 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 the color phosphor on which the electron beam is incident is applied to the G1 electrode 13.

Next, vertical scanning will be explained using FIG. 3. As described above, the vertical scanning electrode 1 is arranged so that the potential of the space surrounding the linear cathode 10 is more positive or negative than the potential of the linear cathode 10.
By controlling the voltage of 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, the voltage for controlling ON/OFF of the beam from the cathode may be small. When the vertical scanning electrode 12 uses an interlaced method, in the first field, one of the vertical scanning electrodes
From 2A, the beam is generated (hereinafter ON) signal for only one horizontal scanning period (hereinafter 1H), and during the next 1H, the beam is turned ON at 12C, and then sequentially.
Beam is ON only for 1H for every other vertical scanning electrode
When the 12X signal at the bottom of the screen is completed, the vertical scanning of the first field is completed. The next second field is from 12B in the same way.
A signal is applied that turns the beam ON only for 1H,
Finally, one frame of vertical scanning is completed by scanning up to 12Y.

Next, we will explain a generally well-known method for the signal processing system until the video signal is applied to the beam modulation electrode of a cathode ray tube that has a plurality of beam generation sources in the horizontal direction, such as the above-mentioned flat-type cathode ray tube. 4
This will be explained using diagrams.

Based on the television synchronization signal 42, a timing pulse generator 44 generates timing pulses for driving circuit blocks to be described later. First of all, one of them
The three primary color signals of _R , _G , and _B (E input to circuit 45; When all the signals for 1H are input, the signals are simultaneously transferred to the second line memory circuit 46, and the next 1H signal is also input to the first line memory circuit 45. The signal transferred to the second line memory circuit 46 is stored and held for 1H, and is sent to the D/A converter (or pulse width converter) 47, where it is converted to the original analog signal (or pulse width modulated signal). signal), which is amplified and sent to the modulation electrode (G1) of the cathode ray tube.
to be applied. This line memory circuit is used for time axis conversion, and its specific description will be explained using the signal waveform shown in the figure.

Let the number of beams used to scan the effective screen area (that is, the number of cathodes) be n, and the area horizontally scanned by each beam is 2 triplets (one triplet is one set of R, G, B phosphor stripes). , dividing the video signal insertion time T of each of the R, G, and B primary color signals 41 during a certain 1H into T/n,
The time axis of the video signal of each period is multiplied by n to T, and the arrangement of phosphor stripes on the phosphor screen is R→G.
→B, each primary color signal multiplied by n and extended to T time is gated with a gate pulse of T/6 time width and converted into a time series signal 48 of E _R →E _G →E _B and input to a predetermined G1 electrode.

When trying to display a faithful color image in a flat cathode ray tube that displays a full color screen through vertical scanning, the aforementioned beam modulation, and horizontal scanning, the electron beam must correspond to the color phosphor that is incident on it. A color modulation signal should be applied to the G1 electrode, but this cathode ray tube does not have this function, and the hue changes when the horizontal deflection width changes. If the electrode spacing is not uniform, each horizontal block will have a different hue.

Purpose of the Invention The present invention solves the above-mentioned problems, and an object of the present invention is to provide a color image display device that eliminates color unevenness caused by horizontal landing variations and enables faithful color image display. It is something to do.

Structure of the Invention In order to achieve the above object, the present invention detects the arrival position of each beam on the phosphor screen only once, stores all the timing signals, and uses the stored arrival position signal to detect the arrival position of each beam on the phosphor screen. This is a color image display device in which the video signal applied to the G1 electrode is switched, and a color signal corresponding to the color phosphor to be emitted upon incidence of the beam is applied to the G1 electrode.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the present invention, after the flat cathode ray tube is manufactured and a predetermined voltage is applied to each electrode, first, a constant voltage is applied to the G1 electrode of only one horizontal block to emit a beam and scan the phosphor screen. . In this state R
Alternatively, by passing the R, G, or B light on the phosphor screen through a G or B filter and receiving it with a photoelectric conversion element such as a photodiode, each R, G, or B phosphor is detected after the beam starts horizontal scanning. Detects the time until scanning. The signal from the photoelectric conversion element thus obtained is input to the memory circuit and stored. The above is performed for one field, and when the above signal storage in one horizontal block is completed, the same operation is performed for the next horizontal block, and sequentially, for each horizontal block, each R or G
Alternatively, a signal corresponding to the time until the B phosphor is scanned is stored.

Next, when displaying a color image, the stored signals of each horizontal block are read out simultaneously in synchronization with each horizontal scan, and based on the read signals,
This is done by switching the timing of the color signal applied to the G1 modulation electrode.

FIG. 5 shows a first embodiment of the present invention. Reference numeral 51 denotes a flat cathode ray tube that has been manufactured, and the internal electrode configuration is the same as that shown in FIGS. 1 to 3 above, and is therefore omitted. Now, among the plurality of horizontal blocks of the flat cathode ray tube 51, a predetermined voltage is applied to each electrode of only one horizontal block marked with diagonal lines so that the electron beam scans the phosphor screen. FIG. 6 shows an enlarged horizontal cross-section of the phosphor screen. The fluorescent screen is R on the inner surface of the vacuum container of the transparent glass plate 61.
Three primary color phosphor stripes 62 of G and B are sequentially repeated in the horizontal direction via a black stripe 63 for blocking light, and a metal back electrode 64 made of aluminum or the like is formed thereon. Here, the number of trios (one set of R, G, B phosphor stripes) included in one horizontal block is defined as m, and each horizontal scan is performed from R→G→B→R... as shown by arrow A in FIG. G →
Suppose you want to scan B. At this time, the horizontal deflection amplitude is slightly increased, and scanning is started from a position where the R phosphor of the adjacent horizontal block is not scanned.
A timing signal when the electron beam scans the R phosphor is obtained by receiving the light at a photoelectric conversion element 53 such as a photodiode through a filter 52 that allows only the light of the wavelength from the R phosphor to pass through. This is shown in FIG. Arrow B is the horizontal scanning width, and 71 is a signal waveform obtained by extracting only the fundamental frequency component of the output from the photoelectric conversion element 53. A signal waveform 72 is obtained by passing this through a limiter circuit. The above bandpass filter and limiter circuit is shown as a waveform shaping circuit at 54 in FIG. Here, the signal 72 has a time delay of Δτ _p from when the beam scans the center of the phosphor due to the rise characteristics of the light emission of the phosphor and the delay characteristics of the waveform shaping circuit. This signal 72 is input to the memory circuit 55. In the memory circuit 55, the frequency f p of the waveform shaping circuit output 72 synchronized with the leading edge or trailing edge of the horizontal synchronizing pulse generated by the synchronizing separation circuit 56 or the horizontal blanking pulse 73 generated based on this is higher than the frequency f _p of the waveform shaping circuit output 72. Generate a reference signal 74 lower than f _p +f _H (f _H ; horizontal scanning frequency),
Measure the time t ₁ , t ₂ , t ₃ , . . . t _o from the fall or rise of this signal to the rise or fall of the input signal 72 from the waveform shaping circuit 54,
Memorize this. Here, the reference signal 73 has a memory capacity and a time t ₀ from the point of phase compensation described later to its start adjusted. At this time, it goes without saying that the signals from each horizontal scan are stored in memory in synchronization with the vertical scan. R obtained by horizontal scanning of each beam of one horizontal block as described above.
can store timing signals in memory.

The same process is performed for the other horizontal blocks, and the timing signal for the beam scanning over the R phosphors on the entire screen of the flat cathode ray tube is memorized. The memory element used in the memory circuit 55 is a non-volatile one.

When the above operations are completed, the parts within the dotted line frame in FIG.
Then, the waveform circuit 54 is removed, and the operation shifts to actually displaying a color image.

When displaying a color image on the flat cathode ray tube 51, the signals from the sync separation circuit 56 are used to simultaneously read out the stored signals corresponding to the corresponding horizontal scanning positions of each horizontal block. Here, one horizontal block among them will be explained.

A reading reference signal 75 having the same frequency as the reference signal 74 generated when writing to the memory is generated in synchronization with the horizontal synchronizing signal 73. At this time, the time t ₀ ' from the rising edge of the horizontal synchronizing signal 73 to the start of the reading reference signal 75 is t ₀ '<t ₀ , and the memorized time t ₁ , from the falling edge of this signal 75,
After t ₂ ...t _o, a signal 76 of a predetermined width is generated and inputted to the three-phase pulse generator 57. The reason why the start time t ₀ ' of the reading reference signal 75 is made smaller than t ₀ is because of the delay time in the signal processing circuit after reading until the signal is applied to the modulation electrode of the flat cathode ray tube 51. This is to compensate. In the three-phase pulse generator 57, the input signal 7 to the memory circuit 55 is
By generating a signal having the same frequency as 2 and having a phase different from each other by 120 degrees, and using this as a readout signal from the line memory 58 corresponding to the second line memory 46 described in FIG. 4, A time-series point-sequential signal of R→G→B→R, →, etc. is obtained. The signal obtained from this second line memory 58 is converted into an analog signal by a D/A converter 59 (or pulse width conversion), which is amplified by an amplifier 60 and sent to the modulation electrode of the flat cathode ray tube 51. Apply. Here, as an example, a signal 77 is shown to be applied to the modulation electrode when only R is displayed.

In the embodiment described above, a predetermined voltage is applied to the flat cathode ray tube that has been manufactured, the electron beam scans the phosphor screen, and the timing at which each beam scans the R, G, or B phosphors is detected. When storing this information and displaying an actual color image, read out the memorized timing signal and, based on this signal, adjust the color video signal to be applied to the flat cathode ray tube to the position of the phosphor screen of the beam. Color image display is performed by controlling accordingly.

Next, a second embodiment of the present invention will be described. Fig. 8 shows a flat cathode ray tube used in the second embodiment of the present invention, where [A] is an external view of the flat cathode ray tube, and [B] is an enlarged view of the main parts viewed from the front. It is a diagram.

Regarding the area for displaying color images, see the fifth section above.
Similar to the figure, three primary color phosphor stripes 82 of R, G, and B are sequentially repeated in the horizontal direction via a black stripe 84. Further, an index phosphor 83 is formed outside the effective screen for displaying the color image. Here, the number of index phosphors is sufficient for at least one horizontal block, and the number of index phosphors is equal to or greater than the number of trios of color phosphors included in one horizontal block. FIG. 8B shows one example of this, in which two trios of color phosphors 82 are provided in one horizontal block 85, and four index phosphors 83 are provided corresponding to the G phosphor positions. Show what was received. The index phosphor 83 may be of R, G, or B, but R, G, or B, such as near-ultraviolet P-16
B phosphors having different emission wavelengths may be used.

FIG. 9 shows a vertical sectional view of the electrode configuration of one horizontal block in which the index phosphor 83 of the flat cathode ray tube 81 described above is formed. Although the electrode structure is the same as that shown in FIGS. 1 and 2, only the cathode 90 and the G1 electrode 93, which are the beam generation sources for scanning the index phosphor 83, are different. That is, the linear cathode 90 is connected to at least one support 8 within the effective screen area 90-a and outside 90-b.
6, and the G1 electrode 93 is electrically separated into the inside 93-a of the effective screen and the outside 93-b. A filter 88 and a photoelectric conversion element 89 are attached to the outside of the vacuum envelope of the face glass 87 in correspondence with the index phosphor 83, allowing light having the emission wavelength of the index phosphor 83 to pass therethrough. Here, the filter 88 does not necessarily need to be attached, nor should the cathode 90 be separated by a support.

A method of driving the flat cathode ray tube 81 described above will be described below. FIG. 10 shows the main system of the drive circuit, and FIG. 11 shows signal waveforms. The same parts as those in the driving method shown in FIG. 5 explained in the first embodiment are given the same numbers.

This embodiment also basically operates in the same manner as the first embodiment, in which only one of the plurality of horizontal blocks of the flat cathode ray tube 101 scans the fluorescent screen with the electron beam. At this time, the 8th
The index phosphor section explained in FIGS. 9 and 9 is also driven so as to be beam scanned at the same time. FIG. 11 shows the relative positional relationship between the index phosphor section 111 and the color display section 112 made of three primary color phosphors. In this embodiment as well, the beam is deflected wider than one horizontal block width 113 (114). Assuming that the beam now scans the color phosphor of the color display section 112 from left to right in FIG. 11, the R filter 52, the photoelectric conversion element 5
3. Obtain the output signal 116 by the waveform shaping section 54. On the other hand, the index phosphor section 111 is also beam-scanned, and the photoelectric conversion element 89 and the waveform shaping section 102
A signal 115 is obtained, and in this embodiment, this signal 115 is used as a reference signal. Thus,
The time from the fall of the reference signal 115 to the rise of the signal 116 from the color display section (τ+t ₁ ), (τ+
t ₂ ) may be stored in the memory circuit 55, but as will be described later, in order to compensate for the delay time τ ₀ between reading the signal from the memory circuit and applying the signal to the flat cathode ray tube 101. , the times t ₁ and t ₂ from the falling edge of the reference signal 115 to the rising edge of the signal 116 on the color display unit are stored. This also reduces the capacity of the memory element.

By writing the above-mentioned signals into the memory circuit 55 for each horizontal block, the timing signal of the beam for scanning the R phosphors on the entire screen can be stored using the signal from the index phosphor section as a reference. Therefore, the index phosphor section is always beam-scanned no matter which horizontal block is operated.

Next, the process moves to displaying a color image. At this time, the portion within the dotted line frame in FIG. 10 becomes unnecessary. The index phosphor section 111 is constantly beam-scanned, and a reference signal 115 is obtained from the waveform shaping section 102, which serves as a reading reference. Therefore, a signal 117 of a predetermined width is generated after t ₁ and t ₂ have elapsed from the falling edge of the reference signal 115, and is inputted to the three-phase pulse generator 57.
A signal shown at 9,120 is generated. Since the subsequent signal processing system is the same as that of the first embodiment shown in FIG. 5, the explanation will be omitted.

The difference between the second embodiment described above and the first embodiment is in how the reference signal for writing and reading into the memory circuit is generated. In the first embodiment, the reference signal is generated based on the horizontal synchronization signal. In the second embodiment, this is generated by beam scanning an index phosphor section provided outside the effective screen.

Effects of the Invention The present invention applies a predetermined voltage to cause each beam to scan over a phosphor screen, detects the entire timing signal of each beam scanning a predetermined phosphor position, and stores this only once at the beginning. Based on the stored signals, the timing of the video signal applied to the modulation electrode of the flat cathode ray tube is controlled in accordance with the position of the phosphor screen of the beam, thereby displaying a color image. Even if slight errors occur during assembly when manufacturing the tube, resulting in variations in the horizontal deflection width and horizontal landing position of each beam, a faithful color image can be displayed without color unevenness.

[Brief explanation of drawings]

Figure 1 is a perspective view showing the configuration of a flat cathode ray tube;
FIG. 2 is a horizontal sectional view thereof, FIG. 3 is an explanatory diagram of vertical scanning operation, FIG. A drive circuit system diagram of a flat plate cathode ray tube according to an embodiment, FIGS. 6 and 7 are partially enlarged views and operation waveform diagrams, and FIGS. 8A and B are a diagram of a flat plate cathode ray tube according to a second embodiment of the present invention. A perspective view and an internal front view of a cathode ray tube, FIG. 9 is a vertical sectional view of FIG. 8, and FIG.
The figure is a system diagram of the drive circuit, and FIG. 11 is a signal waveform diagram of each circuit section. 10,90... Linear cathode, 12,92...
Vertical scanning electrode, 13,93...G1 modulation electrode,
14,94...G2 electrode, 15,95...G3 electrode, 16,96...G4 electrode, 17,97...horizontal focus electrode, 18,98...horizontal deflection electrode, 43...A/D converter, 44...Timing pulse generator, 75...First line memory, 76...Second line memory, 77...D/
A converter, 52... Color filter, 53...
...Photoelectric conversion element, 54...Waveform shaping section, 55...
Memory, 56... Synchronous separator, 57... Three-phase pulse generator, 58... Second line memory, 59
...D/A converter, 60...Amplifier, 83
. . . index phosphor, 88 . . . color filter, 89 . . . photoelectric conversion element, 102 . . . waveform shaping section.

Claims (1)

[Claims] 1. All timing signals for the beam to scan a predetermined position on a phosphor screen in which at least three primary color phosphors of red, green, and blue are repeatedly arranged sequentially in the horizontal direction through a black area are first transmitted. It is characterized by being memorized only once, and displaying a color image by reading out the memorized timing signal and controlling the color video signal applied to the flat cathode ray tube based on this signal in accordance with the position of the beam on the phosphor screen. A method for driving a flat cathode ray tube. 2 Fluorescence is generated by placing a photoelectric conversion element with a red, green, or blue filter on the front of a flat cathode ray tube, whose fluorescent screen is scanned with a fixed amount of beam by applying a predetermined voltage. 2. The method of driving a flat cathode ray tube according to claim 1, further comprising detecting a timing signal when the beam scans each red, green, or blue position on the surface. 3 Based on the television synchronization signal, generate a reference signal with a frequency higher than the fundamental frequency of the timing signal and whose difference is lower than the horizontal scanning frequency, store the phase difference between the reference signal and the timing signal, and generate the reference signal. 2. A method for driving a flat cathode ray tube according to claim 1, wherein the original timing signal is regenerated from the phase difference signal stored based on the phase difference signal. 4. A method for driving a flat cathode ray tube according to claim 3, wherein delay characteristics of the drive circuit system are compensated for by changing the phase of the reference signal. 5. By applying an index phosphor outside the effective display screen area and scanning the phosphor part in synchronization with a beam that always scans the effective display screen area, light from the phosphor part is transferred to the photoelectric conversion element. A patent characterized in that a reference signal is generated by receiving a signal at a timing signal, a phase difference between the reference signal and a timing signal is stored, and the original timing signal is reproduced from the stored phase difference signal based on the reference signal. A method for driving a flat cathode ray tube according to claim 1. 6. A claim characterized in that a screen is divided into blocks for display using a plurality of electron beam sources, and the position of the phosphor screen is individually controlled for each electron beam of each block. 2. A method for driving a flat cathode ray tube according to item 1.