JPS62183291A - Color picture display device - Google Patents

Abstract

PURPOSE:To accurately regulate the phase correlation with the B-positional signal by disposing an index area wider by two triplet of a colored phosphor or above, frequency dividing the frequency of an index signal to a half, and consecutively varying the phase of the signal. CONSTITUTION:The light emitted by the index phosphor is converted to an electrical signal by a photoelectric transducer 53, and shaped into a square wave by such as a limiter in a waveform shaping circuit 70. The light emitted by a B phosphor is also converted to an electrical signal, and sorted in odd number pulse and even number pulse. The said signals respectively are inputted to phase difference measuring circuits 77 and 78, where the phase differences between the odd number pulses of the index signal and the B positional signal and between the even number pulses of the same are measured, and the results are stored in a memory 56. To measure the phase difference, the counting of clock pulses synchronized with horizontal driving signals(H.D.) is started by the index signal pulse, and ended by the B positional signal pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention 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.

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. 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 1o 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 1o and the spacing between them are arbitrary. For example, if the display screen size is 10", the horizontal spacing between them is approximately 102, and 20 linear cathodes are arranged vertically. Approximately 160
+m length. On the opposite side of the face plate portion 9 across the linear cathode 1o, there are disposed on the insulating support 11 in close proximity to the linear cathode 1° at equal pitches in the vertical direction.
Further, vertical scanning electrodes 12 that are electrically divided and elongated in the horizontal direction 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 1o 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 1o are divided between adjacent cathodes. , a first grid electrode (hereinafter referred to as G1) 13. which performs beam modulation by applying a video signal to each of the electrodes. A second electrode which has the same opening as the G1 electrode 13 and is not electrically divided in the horizontal direction.
A grid electrode (hereinafter referred to as G2) 14 and a third grid electrode (hereinafter referred to as G3) 15 are arranged. Next, 02 electrode 14, G3
A fourth grid electrode (hereinafter referred to as G4) 16 having an opening that is equal to or wider in the horizontal direction than the opening of the electrode 16 is arranged.

Next, a horizontal focus electrode 17 and a horizontal deflection electrode 18, which are formed by plating or vapor deposition on the surface of the insulating support 19, are arranged symmetrically about 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 back electrode 8 is formed on the inner surface of the face plate 9.

In the case of color display, the phosphors are formed as stripes or dots of red R1 green G and blue B sequentially in the horizontal direction.

Next, FIG. 6 shows the operation of the color cathode ray tube.

This will be explained using FIG. The linear cathode 10 is heated by passing a current through it, and the same voltage as the potential of the cathode 10 is applied to the G1 electrode 13 and the vertical scanning electrode 12. At this time G1. The beam advances from the cathode 1o toward the G2 electrode (13, 14), and a voltage (1
oo~300V) is applied to the 02 electrode 14. Here the beam is G1. The amount of light passing through each hole of the G2 electrode is controlled by changing the voltage of the G1 electrode 13. The beam passing through the aperture of the G2 electrode 14 is transferred to the G3 electrode 1.
5 → G4 electrode 16 → horizontal focus electrode 17,
A predetermined voltage is applied to these electrodes so that the electron beam forms a small spot on the fluorescent surface. Here, the beam focus in the vertical direction is performed by an electrostatic lens formed at the exit of the aperture of the G4 electrode 16, and the beam focus in the horizontal direction is performed by an electrostatic lens formed between the horizontal focus electrode 17 and the horizontal deflection electrode 18. It is done with a 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 having a horizontal scanning period at the horizontal deflection electrode 18, and stimulates the phosphor 7 to obtain a luminescent image. , 7-power color image (to obtain an image, as described above, when each electron beam horizontally scans the phosphor 7, the modulation signal of the color corresponding to the color-changing light body on which the electron beam is incident is 01 is applied to the electrode 13.

Next, vertical scanning will be explained using FIG. 6.

As described above, by controlling the voltage of the vertical scanning electrode 12 so that the potential of the space surrounding the linear cathode 1o becomes more positive or negative than the potential of the linear cathode 1o, the linear cathode 1o The generation of electrons from is controlled. At this time, if the distance between the linear cathode 1o 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 interlace method, a beam is generated from the vertical scanning electrode 12A for one horizontal scanning period (hereinafter 1H) in the first field (hereinafter ON).
) signal is applied, then a signal that turns on the beam to 12G during the next 1H, and then a signal that turns on the beam only for 1H to every other vertical scanning electrode, and 12X at the bottom of the screen.
When this is completed, the vertical scanning of the first field is completed. In the next second field, a signal is applied that turns on the beam only during 1H, similar to 12B, and finally to 12Y.
By scanning up to this point, one frame of vertical scanning is completed.

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. This will be explained using FIG.

Timing pulse generator 4 based on TV synchronization signal 42
4, a timing pulse is generated to drive a circuit block to be described later. First, the three primary color signals of R, G, and B (IER, IEG
, KB) 41 is converted into a digital signal by the MU/D converter 43, and the 1H signal is input to the first line memory 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 46. Second
The signal transferred to the line memory circuit 46 is stored and held for 1H, and is sent to the D/M converter (or pulse width converter) 47, where it is converted to the original analog signal (or pulse width modulation signal). This is amplified and applied to the modulation electrode (G1) of the cathode ray tube. 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.

The number of beams used to scan the effective screen area (
In other words, if the area horizontally scanned by each beam is n and the area horizontally scanned by each beam is 2 triplets (one triplet is one set of R, G, and B phosphor stripes), then the R
, G, B each primary color signal 41 video signal insertion time T is T/1
/2, and multiply the time axis t-n of the video signal of each period to T, and the arrangement of the phosphor stripes on the phosphor surface is R-
.
8 and input to a predetermined 01 electrode.

・Vertical scanning as described above and beam modulation as described above,
When trying to display a faithful color image on a flat cathode ray tube that displays a full color screen through horizontal scanning,
A modulation signal of the color corresponding to the color changing light body into which the electron beam is incident should be applied to the 01 electrode, but this cathode ray tube does not have this function, and the hue changes when the horizontal deflection width changes. Furthermore, when manufacturing this cathode ray tube, if the intervals between the horizontal deflection electrodes are not uniform, each horizontal block will produce a color image with a different hue.

In a flat cathode ray tube that displays an image by vertical scanning, beam modulation, and horizontal scanning as described above,
When trying to display a faithful color image, the modulation signal of the color corresponding to the color changing light body on which the electron beam is incident is G1.
must be applied to the electrode. As a method for this, the present applicant previously proposed a method for determining the timing to apply a modulation signal based on an index signal. The method will be explained using FIGS. 8 and 9.

As shown in FIG. 8, an index area 61 is provided outside the image display area 62 on the face plate 60. In this index area 61, as shown in FIG.
The coating is applied so that the relative position with respect to the image display area 62 is in a predetermined relationship, and the beam is scanned in the same manner as in the image display area 62 to emit light.

The index phosphor 61 may have the same or different emission wavelength as the color changing phosphor 60. This light emission is converted into an electric signal by a photoelectric conversion element 63 placed in front of the face plate, and subjected to processing such as waveform shaping and frequency division to become an index signal A (FIG. 8B). On the other hand, the light emitted from the blue B phosphor in the image display area 52 is converted into an electrical signal by another photoelectric conversion element 64 similarly placed in front of the face plate, and the waveform is shaped to produce the B color changing phosphor. Position as signal port. The reason why the light emitted from the B phosphor was received here is that a signal with a fast response speed can be obtained due to the short afterglow.

The phase relationship between the index signal A and the B position signal port obtained in this way is as follows, if the assembly accuracy of the cathode ray tube is good.
The relationship is as shown in FIG. 8B.

Therefore, from each rising edge of index signal A, B
Time difference to each rising part of position signal port 11.12
．． . . . is measured and stored in the memory 56. This operation is performed in advance over the entire image display area without applying a color modulation signal. When actually displaying an image, the timing at which the B color signal is applied is set at the time when the time stored in the memory 66 has elapsed from each rising edge of the index signal A. Also, for R and G color signals, this timing signal is
Application timing can be obtained by multiplying.

As described above, a color modulation signal corresponding to the color phosphor on which the electron beam is incident is applied to the 01 electrode, and faithful color image display is performed.

Problems to be Solved by the Invention The phase relationship between the index signal A and the B position signal port described above cannot necessarily be as shown in FIG. 8, depending on the assembly accuracy of the cathode ray tube. In other words, as shown in FIG. 10, if the starting position of the horizontal scanning of the electron beam is relatively shifted between the image display area and the index area, the phase relationship between the index signal and the B position signal will not correspond correctly. As a result, the color phosphor on which the beam is incident and the timing of applying the color modulation signal to the 01 electrode do not correspond correctly.

For example, if the scanning start position of the electron beam is the point indicated by 1, the first pulse point of index signal A is 0.
The pulse Bo at the B position signal port, which should correspond to this, is delayed by one period, that is, one triblet of color phosphor, from the correct position. Furthermore, if the scanning start position of the electron beam is the point indicated by 2, then the phase of the B position signal port is ahead of the phase of the index signal A, and the phase corresponding to the pulse Bo of the B position signal port is higher than that of the index signal A. However, there is no pulse of the index signal A, and the timing for applying the modulation code is lost. Therefore, the scanning start position of the electron beam must be at a point where the phase of the B position signal port does not lead the phase of the index signal A and does not lag by more than one triplet. However, it is difficult to maintain the assembly accuracy of the cathode ray tube so that the above-mentioned relationship holds over the entire image display area.

Means for Solving the Problems The index area is made wider by at least two triplets of color phosphors than one horizontal scanning section of the image display area, and means is provided for dividing the frequency of the obtained index signal into stations. Furthermore, by providing means for continuously changing the phase of the index signal, the phase relationship with the B position signal can be adjusted correctly.

Effect: With the means described above, the index signal can be obtained from a range wider than one horizontal scanning section of the image display area by at least two triplets of color phosphors, so even if the phase of the B position signal leads the phase of the index signal, There may be corresponding pulses of the index signal, and the means for adjusting the phase of the index signal makes it possible to adjust the correspondence between the pulses of the index signal and the pulses of the B position signal to the correct position. Further, by means of dividing the frequency of the index signal into %, the range in which the above-mentioned phase can be adjusted can be expanded to two triplets of color phosphors. Therefore, the index signal and B
Since the phase shift of the position signal can be tolerated to be more than twice that of the conventional method, the margin of accuracy in assembling the cathode ray tube can be more than doubled.

Embodiment FIG. 1 is a block diagram of main parts of a color image display device according to an embodiment of the present invention, and FIG. 2 is a diagram showing waveforms of each part. The light emitted from the index fluorescent material is converted into an electrical signal by a photoelectric conversion element 63, and then shaped into a rectangular wave by a limiter or the like by a waveform shaping circuit element 0. As shown in FIG. 6 of the conventional example, the index phosphor 61 is one of the color phosphors 6o.
Since the pitch is 3/2 times the pitch of the triplet, the frequency is divided by 2/3 by the divider 71 to match the repetition frequency of the B position signal. The branching unit 71 includes a delay circuit,
This can be realized using an E-OR circuit and a counter.

The output of the frequency divider 71 is sorted into odd-numbered pulses and even-numbered pulses by a pulse selection circuit 72 composed of a counter and an AND circuit. That is, the index signal is converted into two systems of signals obtained by frequency-dividing the conventional signal by %. The index signals 2 and 7 are inputted to phase difference measuring circuits 77 and 78 through phase shift circuits 73 and 74, respectively. Phase shift circuits 73 and 74 are monostable multivibrator 2, respectively.
The index signals 2 and 5 can have their phases changed within the range of their respective repetition periods. Therefore, the phase adjustment range is as follows: color changing light, body 60
It can be done for up to 2 triplets.

On the other hand, the light emitted from the B phosphor is converted into an electric signal by the photoelectric conversion element 64, and after being shaped into a rectangular wave by the waveform shaping circuit 76 in the same manner as the index signal, it is sorted into odd numbered pulses and even numbered pulses. and are input to phase difference measuring circuits 77 and 78, respectively.

The phase difference measuring circuits 77 and 78 measure the phase difference between the odd-numbered pulses of the index signal and the B position signal, or between the even-numbered pulses, and store them in the memory 56. Phase difference measurement may be performed by starting counting clock pulses synchronized with the horizontal drive signal (H, D) with an index signal pulse and ending counting with a B position signal pulse.

As mentioned above, by measuring the phase difference after dividing the index signal and the B position signal by %, and by making the phase of the index signal variable, the phase of the B position signal is smaller than the phase of the index signal. Even if a delay of one triblet or more occurs in the color changing light body, the phases of both can be made to correspond to the correct positions.

Still, the application area of the index phosphor 61 is expanded and the third
As shown in the figure, the index phosphor 61 is applied to an area wider than one horizontal scanning section of the image display area by at least two triplets. By doing this, the lead of the phase of the B position signal with respect to the phase of the index signal, which occurs in the conventional example, can be tolerated by up to two triplets.9 With respect to the first pulse of the B position signal, There is no longer a situation where the index signal does not exist.

Effects of the Invention According to the present invention, it is possible to tolerate a deviation between the phase of the index signal and the phase of the B position signal to a range that is more than twice that of the conventional method. It is possible to more than double the margin of assembly accuracy.

[Brief explanation of drawings]

FIG. 1 is a block diagram of main parts of a color image display device according to an embodiment of the present invention, FIG. 2 is a waveform diagram of each part of FIG. 1, and FIG.
7 is a signal processing system diagram of a color image display device, FIG. 8 is an explanatory diagram of the basic principle of the index method, and FIG. FIG. 9 is a diagram showing the configuration of a fluorescent surface of a conventional color cathode ray tube, and FIG. 1o is a diagram for explaining the problems of the index method in the conventional example. 50... Flat color cathode ray tube, 51...
...Index area, 62...Effective screen area, 53.54...Photoelectric conversion element, 66...River...
Memory, 6o... Color changing light body, 61...
Index phosphor, 70.75...Waveform shaping circuit, 72.76...Pulse selection circuit, 73.
74... Phase shift circuit, 77, 78...
Phase difference measurement circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 4 Diagram 66 Figure 5 Figure 1 C ZY /2Z Figure 7 Secret l wire case

Claims (1)

[Claims] an image display area provided with a phosphor surface in which at least three primary color phosphors of red, green, and blue are repeatedly and sequentially arranged through a black area in the horizontal direction; and an index phosphor outside the image display area. It has an image display element provided with an array of index areas, the index area is scanned in synchronization with an electron beam that constantly scans the image display area, and light from the index area is received by a photoelectric conversion element to obtain an image. means for controlling the application timing of the color modulation signal according to the index signal provided, and the range in which the index signal is obtained is set to be wider than one horizontal scanning section of the image display area by at least two triplets of primary color phosphors. A color image display device, further comprising means for dividing the repetition frequency of the obtained index signal into 1/2, and further comprising means for adjusting the phase of the frequency-divided index signal.