JPH051579B2 - - Google Patents

Description

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

BACKGROUND ART Conventionally, as a flat cathode ray tube, a structure as shown in FIG. 6 has been described in Japanese Patent Application Laid-Open No. 46-2619. That is, a phosphor 2 is formed on the inner surface of a vacuum envelope 1, and a vertical deflection electrode 3, which is elongated in the horizontal direction and divided at a predetermined pitch in the vertical direction, is arranged parallel to and opposite to the phosphor 2. It consists of a structure in which an electron gun for producing individual electron beams is arranged in a horizontally elongated direction in the vertical scanning extension direction of the fluorescent surface. The operating method of a flat plate cathode ray tube having these structures is that thermionic electrons generated by heating the electron source 4 are extracted as an electron beam 8 through an opening provided in the grid electrode 5, and then Modulation is performed on each individual beam by . The modulation method is performed by electrically dividing the individual apertures and applying individual beam modulation voltages to each electrode. Next, each modulated electron beam passes through the aperture of the seedling electrode 7, and then passes between the fluorescent surface 2 and the vertical deflection electrode 3 provided opposite thereto, for example, between the fluorescent surface 2 and the vertical deflection plate 3. and where they are at the same potential (V _D ), go straight,
Next, at the vertical deflection electrode 3 to which a potential (V _D −V _CC ) lower than V _D is applied, the electron beam is deflected toward the phosphor surface 2 due to the influence of the electric field and strikes the phosphor. Make it emit light. By sequentially performing these deflection operations on each of the vertical deflection electrodes 3, vertical scanning of the electron beam can be performed, and by these operations, a normal television image can be displayed on the fluorescent surface.

However, in this flat cathode ray tube, the electron gun that generates the electron beam needs to generate individual electron beams for each pixel in the horizontal direction, and one pixel in a normal television image is a color image. Approximately 0.1
Since the pitch is ~0.2 mm, there are major electrical and mechanical problems in generating electron beams at these pitches and modulating them individually. Even if these are possible, it is difficult to make the spot diameter of the electron beam and the accuracy of the incident position on the phosphor surface constant for each beam in the electron beam traveling section from the electron gun section to the phosphor section. It is extremely difficult. Further, since the vertical deflection electrode 3 is at the same potential as the fluorescent surface 2, the switching operation is performed at a high voltage, and the deflection power is also considerably large.

As described above, although this flat cathode ray tube has the advantage of a simple structure, it has many problems in terms of performance and the like.

Problems to be Solved by the Invention The present invention relates to a novel flat cathode ray tube that solves the problems of the flat cathode ray tube described above.
The object of the present invention is to provide a flat cathode ray tube which has a simple structure and beam control, has no variation in beam spot diameter and landing characteristics, and has high deflection sensitivity.

Means for Solving the Problems The present invention provides divided electrodes for vertical scanning for performing electron beam scanning in the vertical direction inside a vacuum envelope, which are long in the vertical direction of the screen and are arranged horizontally in parallel at a predetermined pitch. A plurality of linear cathodes, a modulation electrode provided in 1:1 correspondence to these cathodes and having apertures at positions corresponding to vertical scanning divided electrodes, and apertures at positions corresponding to the apertures of the modulation electrodes. three planar electrodes, two vertical deflection electrodes whose apertures are vertically shifted, and a horizontal deflection electrode arranged corresponding to the middle position of the linear cathode and divided into three in the beam traveling direction. and a face plate equipped with a fluorescent material.

Effect In the above configuration, when the linear cathode is heated and the voltage applied to the vertical scanning divided electrodes is sequentially controlled,
The electron beam passes through the modulation electrode and the apertures in the three planar electrodes, and then passes between the vertical deflection electrode and the horizontal deflection electrode to reach the fluorescent surface of the face plate. At this time, the electron beam is modulated by the video signal by applying the video signal to the modulation electrode. Beam focus in the vertical direction and vertical deflection of each beam are achieved by controlling the voltage applied to the vertical deflection electrode by the planar electrode, and beam focus in the horizontal direction is achieved by controlling the voltage of the horizontal deflection voltage divided into three. Scraps and horizontal deflection are performed. Vertical scanning is performed by sequentially switching the voltages applied to the vertical scanning divided electrodes in the vertical direction.

Examples Examples of the present invention will be described in detail below.
1 to 3 show embodiments of a flat cathode ray tube according to the present invention. FIG. 1 is a perspective view, FIG. 2 is a horizontal sectional view, and FIG. 3 is a vertical sectional view. 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. Furthermore, in order 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 portion. 1
0 is a linear cathode long in the V direction, which is a tungsten wire whose surface is coated with an oxide cathode material, and a plurality of cathodes are arranged independently at equal intervals in the horizontal direction.
On the opposite side of the face plate portion 28 across the linear cathode 10, there are horizontally elongated vertical strips arranged on the insulating support 11 in the vicinity of the linear cathode 10, at equal pitches in the vertical direction, and electrically divided. Scanning electrodes 12 are arranged. These vertical scanning electrodes 12 have the same number of horizontal scanning lines in the vertical direction if displaying a normal television image (approximately
Formed as 1/2 independent electrode (480). Next, between the linear cathode 10 and the face plate portion 28, from the linear cathode 10 side, planar electrodes having openings in portions corresponding to the linear cathode 10 and the vertical scanning electrode 12 are connected to the adjacent linear cathodes 10 and the face plate portion 28. The first grid electrode (hereinafter referred to as G1) 13 is divided between the cathodes 10 and performs beam modulation by applying a video signal to each divided electrode. A second grid electrode (hereinafter referred to as G2) 14 and a third grid electrode (hereinafter referred to as G3) 15 which are not divided are arranged. The G2 electrode 14 is for generating an electron beam from the linear cathode 10,
The G3 electrode 15 is for shielding the electric field generated by the subsequent electrode and the beam generation electric field. Next, a fourth grid electrode (hereinafter referred to as G4) has an opening that is larger in the horizontal direction than in the vertical direction at a position corresponding to the linear cathode 10.
16 are placed. At the rear of the G4 electrode 16, there are two electrodes 17 and 18 that have apertures that are sufficiently wider in the horizontal direction than in the vertical direction, similar to the apertures in the G4 electrode 16.
and two electrodes 17, as shown in FIG.
A vertical deflection electrode is formed by shifting the center axis of the opening 18 in the vertical direction. vertical deflection electrode 17,
18, a plurality of vertically long electrodes are provided at positions corresponding to the middle of each of the linear cathodes 10 toward the face plate portion 28 side. Figures 1 to 3 show a three-stage case as an example, and each electrode is connected to the first horizontal deflection electrode (hereinafter referred to as
DH-1) 19, second horizontal deflection electrode (hereinafter referred to as DH-
2) 20, third horizontal deflection electrode (hereinafter referred to as DH-3) 2
1, and each of the horizontal deflection electrodes 19 to 21 is connected to a common bus bar 22, 23, 24 at every other horizontal direction. 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 DH-1 electrode 19,
A voltage is applied to the DH-2 electrode 20 for horizontal focusing of the beam. Face plate part 28
A light-emitting layer consisting of a fluorescent surface 27 and a metal back electrode 26 is formed on the inner surface. When displaying in color, the fluorescent surface 27 sequentially displays red (R), green (G), and blue in the horizontal direction.
The phosphor stripes in (B) are formed through a black guard band.

Next, the operation of the color cathode ray tube will be explained. The linear cathode 10 is heated by passing a current through it, and the G1 electrode 13 and the vertical scanning electrode 12 are heated.
Approximately the same voltage as the potential of the cathode 10 is applied to . At this time, the beam advances from the cathode 10 toward the G1 electrode 13 and the G2 electrode 14, and a voltage higher than the potential of the cathode 10 (for example, 100 to 300 V) is applied to the _G2 electrode 14 so that the beam passes through each electrode aperture. to be applied. Here the beam is G1 electrode 13, G2 electrode 1
The amount passing through each of the holes 4 is controlled by changing the voltage of the G1 electrode 13. The beam passing through the aperture of the G2 electrode 14 passes through the G3 electrode 15,
The electron beam advances sequentially to the G4 electrode 16, the vertical deflection electrodes 17 and 18, and the horizontal deflection electrodes 19, 20, and 21, and a predetermined voltage is applied to these electrodes so that the electron beam forms a small spot on the fluorescent surface 26. Ru. Here, the beam focus in the vertical direction is G ₃ electrode 15,
This is done using an electrostatic lens formed between the _G4 electrode 16 and the vertical deflection electrodes 17 and 18, and the beam focus in the horizontal direction is controlled by the DH-1 electrode 19, the DH-2 electrode 20, and the DH-3 electrode 21, respectively. This is done with an electrostatic lens formed between the two. The two electrostatic lenses are formed only vertically and horizontally, respectively, so that the vertical and horizontal spot sizes of the beam can be adjusted individually.

In addition, DH-1 electrode 19, DH-2 electrode 20, DH
−3 bus bars 22, 23 to which the electrode 21 is connected;
A sawtooth wave, triangular wave, or staircase wave deflection voltage having the same voltage and horizontal scanning period is applied to 24, and the electron beam is deflected horizontally by a predetermined width to scan the fluorescent surface 26 with the electron beam. A luminescent image is thus obtained.

Next, vertical scanning will be explained using FIG. 4. FIG. 4A shows the structure of each electrode, and FIG. 4B shows the voltage waveform applied to each electrode in FIG. 4A, and corresponding parts are given the same reference numerals. 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 10, 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 beam from the cathode is generated (hereinafter referred to as ON) or blocked (OFF).
The voltage to control it may be small. In the case of the current television system that uses an interlaced system, a predetermined deflection voltage is applied to the vertical deflection electrodes 17 and 18 for one field in the first field, and one horizontal voltage is applied to 12A of the vertical scanning electrode 12. A beam ON voltage is applied only during the scanning period (hereinafter referred to as 1H), and a beam OFF voltage is applied to the other vertical scanning electrodes 12B to 12Z. After 1H, the beam ON voltage for 1H is applied only to 12B of the vertical scanning electrode.
Subsequently, the vertical scanning electrodes 12C, 12D,...
A voltage is applied to turn on the beam only for 1H, and when 12Z at the bottom of the screen is completed, the vertical scanning of the first field 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 amplitude of the deflection voltage applied to the vertical deflection electrodes 17 and 18 is adjusted so that the horizontal scanning line of the second field is located between the horizontal scanning line positions of the beam caused by the vertical scanning of the first field. As described above, the same vertical scanning signal voltage is applied to the vertical scanning electrode 12 in both the first and second fields, and the vertical scanning electrode 17,
By changing the deflection voltage applied to the field 18 between the first field and the second field, one frame of vertical scanning is completed.

Next, a signal processing system until a video signal is applied to the beam modulation electrode of a cathode ray tube having a plurality of beam generation sources in the horizontal direction, such as the flat cathode ray tube described above, will be explained with reference to FIG.

Based on the television synchronization signal 42, a timing pulse generator 44 generates timing pulses for driving circuit blocks to be described later. First, R, G, and B are demodulated by one of the timing pulses.
The three primary color signals (E _R , E _G , E _B ) 41 are converted into digital signals by the A/D converter 43, and the 1H
The 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 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 applied to the modulation electrode G1 of the cathode ray tube. Such line memory circuits 45, 46
is used for time axis conversion.

In the above embodiment, the order of the G4 electrode 16 and the vertical deflection electrodes 17 and 18 may be reversed. Furthermore, the number of vertical scanning electrodes 12 is 1/n of the number of horizontal scanning lines (n is an integer of 2 or more), and each vertical scanning electrode 12 is switched every nH.
n stages of deflection voltages may be applied to 18.

Effects of the Invention As described above, the present invention includes a vertically long linear cathode, a plurality of vertical scanning electrodes arranged horizontally, and a plurality of vertical scanning electrodes arranged orthogonally to the linear cathode on the back of the linear cathode. This flat cathode ray tube has a modulation electrode, three planar electrodes, a vertical deflection electrode, and a horizontal deflection electrode arranged between the linear cathode and the face plate in order, and its simple structure and electrode voltage control reduce variations in beam spot diameter and landing characteristics. A flat cathode ray tube with high deflection sensitivity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a flat cathode ray tube according to the present invention, FIG. 2 is a horizontal sectional view of the cathode ray tube, FIG. 3 is a vertical sectional view of the cathode ray tube, and FIGS. 4A and B 5 is a sectional view and a waveform diagram for explaining vertical scanning of the flat cathode ray tube according to the present invention, and FIG. 5 is a drive circuit block diagram of the flat cathode ray tube according to the present invention.
FIG. 6 is a perspective view showing an example of a conventional flat cathode ray tube. 10... Linear cathode, 11... Insulating support,
12...Vertical scanning electrode, 13...First grid electrode, 14...Second grid electrode, 15...Third grid electrode, 16...Fourth grid electrode, 17,
18... Vertical deflection electrode, 19, 20, 21... Horizontal deflection electrode, 26... Metal back electrode, 27...
...Fluorescent material, 28...Face plate, 43...
A/D converter, 44... Timing pulse generator, 45, 46... Line memory circuit, 47
...D/A converter.

Claims (1)

[Claims] 1. A plurality of long linear cathodes are arranged horizontally in a vertical direction parallel to a screen in a vacuum envelope,
An electrically divided vertical scanning electrode of 1/n of the number of horizontal scanning lines (n is an integer of 2 or more) is provided on the back surface of the linear cathode and perpendicular to the linear cathode, and the linear cathode is connected to the linear cathode. On the opposite side from the vertical scanning electrode, an electron beam modulation electrode, a planar grid electrode, a vertical deflection electrode, and a horizontal deflection electrode divided into a plurality of parts in the beam traveling direction are successively provided up to the screen display section. A flat cathode ray tube. 2. The flat cathode ray tube according to claim 1, wherein the modulation electrode is arranged in one-to-one correspondence with the linear cathode, and an electron beam passage hole is provided at a position corresponding to the vertical scanning electrode. 3. A flat cathode ray tube according to claim 1, wherein the vertical deflection electrode comprises two planar electrodes in which the positions of the electron beam passage holes are shifted from each other. 4. The flat cathode ray tube according to claim 1, wherein three planar grid electrodes are provided, each having an electron beam passage hole formed at a position corresponding to the vertical scanning electrode. 5. The flat cathode ray tube according to claim 1, wherein the horizontal deflection electrode is divided into three parts.