JPS63266740A - Flat plate type cathode-ray tube - Google Patents

Abstract

PURPOSE:To reduce the error of the vertical orbit of an electron beam emitted from a filament cathode by making the width of a vertical scanning electrode narrower than the opening length of an electron beam extracting electrode. CONSTITUTION:A filament cathode 23 is formed with an oxide cathode on the surface of a metal fine wire made of tungsten or the like. A G1 electrode 24 is an electrode to extract the electrons emitted from the heated filament cathode 23, and an opening 25 is formed at the position corresponding to a vertical scanning electrode 22. The width (a) of this electrode 22 is made smaller than the vertical opening length (b) of the opening 25 of the electrode 24. The potential gradient between adjoining electrodes 22 is thereby reduced, and the effect on the orbit of the electron beam emitted from the filament cathode 23 is reduced even if the vertical displacement is generated in the positional relationship between the electrode 22 and the G1 electrode 24.

Description

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

2. Description of the Related Art Recently, thin image display devices have been widely used in the field of displaying images, characters, and the like. As for these thin display devices, the present applicant previously published Japanese Patent Application Laid-Open No. 60-18984.
No. 8, JP-A No. 60-193242, he proposed a flat picture tube.

The configuration will be explained below with reference to FIG. In reality, each electrode is housed in a glass container, which is a vacuum envelope, but the vacuum envelope is omitted except for some parts in the figure to make the internal electrodes clear. Further, in order to clarify the horizontal and vertical directions of the screen on which the nine characters and the like are displayed, a horizontal direction 14 and a vertical direction V are illustrated on the face plate portion. Vertically long linear cathode 101
A plurality of wire cathodes 101 are arranged independently at equal intervals, and an oxide cathode is formed on the surface of the tungsten wire. The number of linear cathodes 101 and the spacing between them are arbitrary. For example, if the display screen size is 10 inches, the spacing between them is about 10nvn,
Zero linear cathodes 101 are arranged in the vertical direction with a length of about 160 mm. A face plate portion 102, which is a screen portion separated from the linear cathode 101, and a vertical scanning electrode 103 adjacent to the linear cathode 101 are arranged so as to sandwich the linear cathode 101. The vertical scanning electrodes 103 are elongated in the horizontal direction, and are electrically divided and supported on an insulating support 104 at equal pitches. These vertical scanning electrodes 103 have the number of horizontal scanning lines (N T
(approximately 480 electrodes in the SO method) are formed as independent electrodes. Note that the number of vertical scanning electrodes 103 may be 1/n of the number of horizontal scanning lines. Linear cathode 101, L-
A linear cathode 101 is connected to the face plate 102.
One grid electrode (hereinafter referred to as G electrode) in order from the side.
105, second grid electrode (hereinafter referred to as G electrode) 1
06, Third grid electrode (hereinafter referred to as G3 electrode) 10
7 and the fourth grid electrode (hereinafter referred to as G4 electrode) 10
8 is placed. G, the electrode 105 is the linear cathode 1
A planar electrode having an aperture 109 (see FIG. 3) in a portion corresponding to 01 is divided between adjacent linear cathodes 101, and a video signal is applied to each electrode to perform beam modulation. The G, electrode 106 and the Gj electrode 107 have an opening 110 similar to the Gl electrode 105. 111 (see Figure 3) and is not vertically divided. G4 electrode 108 is G, electrode 106. 0! Opening hole of electrode 107 110°11
1 or wider in the horizontal direction than in the vertical direction (see FIG. 3). A horizontal deflection electrode 113A is provided between the G4 electrode 108 and the face plate 102,
113B and 1130 are arranged symmetrically with respect to the straight axis of electron beam from each filament cathode 101 and at the same spacing as the spacing between the filament cathodes. Each horizontal deflection electrode 113A,
113B and 1130 are formed on the surface of the insulating support 114 by means such as plating or vacuum deposition, and perform horizontal focusing and horizontal deflection. A light emitting layer consisting of a phosphor 115 and a metal back electrode 116 is formed on the inner surface of the face plate 102. Fluorescent material 11
5 is sequentially red @) and green (G) in the horizontal direction when displaying in color.
, blue (B) stripes, or dots.

Next, the operation of the flat picture tube described above will be explained.

In FIG. 3, a current is passed through the linear cathode 11 to heat it, and a voltage approximately the same as the potential of the linear cathode 101 is applied to the G electrode 105 and the vertical scanning electrode 103. At this time, the G1 electrode 105. An electron beam advances from the linear cathode 101 toward the G* electrode 106, and each electrode 105,
Aperture 110 provided in 106. A voltage higher than the potential of the filament cathode 101 (approximately 100 to 500 V) is applied to G! so that the electron beam passes through the part 111. electrode 106
to be applied. Here, the electron beam is G, G, electrode 10
5, each aperture 110 of 106. The amount of light passing through G1 electrode 105 is controlled by changing the voltage of G1 electrode 105. G, the electron beam passing through the aperture 111 of the electrode 106 is transferred to the G1 electrode 107. 04 electrode 108.
Horizontal deflection electrodes 113A facing across the electron beam,
113B and 1130, a predetermined voltage is applied to these electrodes so that the electron beam forms a small spot on the fluorescent surface. Here, beam focusing in the vertical direction is performed by an electrostatic lens formed at the exit of the aperture 112 of the G4 electrode 108, and beam focusing in the horizontal direction is performed by adjusting each center voltage applied to the horizontal deflection electrodes 113A, 113B, and 1130. It can be obtained by changing Also, this horizontal deflection electrode 113A.

113B and 1130 each have two common bus lines 11
3A-a, b, 113B a, b,
1130-a and 1130-b, and through these busbars, the sawtooth wave or step wave deflection power of the horizontal scanning period is simultaneously superimposed on each horizontal focus voltage, and each electron beam is horizontally focused with a predetermined width. deflected in the direction The deflected electron beam stimulates the phosphor 115 to form a luminescent image on the screen. At this time, in order to obtain a color image, etc., when each electron beam horizontally scans the phosphor 115 as described above, the modulation signal of the color corresponding to the phosphor of each color on which the electron beam is incident is transmitted to the G. , may be applied to the electrode 105.

Next, vertical scanning will be explained with reference to FIGS. 4 and 5. As described above, the linear force is controlled by controlling the voltage of the vertical scanning electrode 103 so that the potential of the space surrounding the linear cathode 101 becomes a positive or negative potential compared to the potential of the linear cathode 101. Generation of electrons from node 101 is controlled. At this time, the linear cathode 101 and the vertical scanning electrode 1
03, the voltage for controlling ON/OFF of the electron beam from the linear cathode 101 can be small. When the interlaced method is adopted, the vertical scanning electrode 103 has a signal (hereinafter ON) that generates an electron beam for only one horizontal scanning period (IH) from the vertical scanning electrode 103A in the first field. , 1 during the next 18
A signal to turn on the electron beam is applied to 03C, and then a signal to turn on the electron beam for only 18 periods is applied to every other vertical scanning electrode, and when 103X, which corresponds to the bottom of the screen, is completed, the first 17, the yield Vertical scan is completed. In the next second field, a signal is applied to the vertical scanning electrode 103B to turn on the electron beam only for 18 hours at the same time.
Finally, one frame of vertical scanning is completed by scanning up to 103Y.

In addition, FIGS. 6 and 7 show a signal processing system for applying G to the electrodes for displaying television images using a cathode ray tube having a large number of electron beam generation sources in the horizontal direction, such as the above-mentioned flat color cathode ray tube. Explain with reference to. Based on the television synchronization signal 142, a timing pulse generator 144 generates timing pulses for driving circuit blocks to be described later. First, the video 141 demodulated by one of the timing pulses is converted into a digital signal by the A/D converter 143, and the signal between I and H is input to the first line memo IJ-145. When all the signals between 18 and 18 are input, the signals are transferred to the second line memo') -1
46, and the next IH signal is also input to the first line memory 145. 2nd line memo 1
The signal transferred to 7-146 is stored and held for I1, and is also transferred to D/A converter (or pulse width converter) 1.
47, where it is converted into the original analog signal (or pulse width modulation signal), amplified, and applied to each G and electrode 105 of the cathode ray tube. Here, the line memory is used for time axis conversion, and its specific explanation will be given using FIG. 7. Number of electron beams (i.e. number of cathodes) used to scan the display screen area
Let A be the video signal insertion time T of the video signal 151 between certain IHs, divide it into T/A, multiply the time axis of the video signal of each divided period by and extend it to T time, This signal 152 is applied to each corresponding G1 electrode 105. In this way, the image of the entire IH is displayed,
By sequentially performing this by vertical scanning, the entire image can be synthesized on the screen.

Problems to be Solved by the Invention In the configuration shown in the above conventional example, the vertical scanning electrode 103 and the Gl
The positional deviation between the electrode 105 and the aperture causes an error in the vertical trajectory of the electron beam emitted from the linear cathode 103. For example, as shown in FIG. 8, a vertical scanning electrode 103 is formed on an insulating support 104, and a linear cathode 101. Furthermore, when the electrode 105 is arranged and the electrode width of the vertical scanning electrode 103 is equal to the vertical opening of the 01 electrode 104 and is 0.8 rom, according to the electron beam trajectory calculation, the vertical scanning electrode L01 is 01 electrode 105 in the vertical direction, the face plate 1
The position of the electron beam on 02 is shifted by 0.35 mm. As a result, the image quality on the final screen becomes inferior.

The present invention is intended to solve the above problem, and aims to reduce the error in the vertical trajectory of the electron beam emitted from the linear cathode 101.

Means for Solving the Problems The present invention provides a vertical scanning method in which a linear cathode is sandwiched in a vacuum container, a plurality of vertical scanning electrodes are provided, and G electrodes are provided with openings at positions corresponding to the vertical scanning electrodes. The electrode width is G,
The above-mentioned problem is solved by making the length of the aperture in the electrode in the vertical direction smaller.゛By making the electrode width of the active vertical scanning electrode smaller than the vertical aperture length of the 01 electrode, the potential gradient between adjacent vertical scanning electrodes becomes smaller, and the potential gradient between the adjacent vertical scanning electrodes becomes smaller. Even if a shift occurs, it has little effect on the trajectory of the electron beam emitted from the filamentary cathode.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional side view of a vertical scanning electrode section for explaining an embodiment of a flat cathode ray tube according to the present invention. Other parts are the same as those shown in FIGS. 2 to 7, and illustration and description thereof will be omitted.

In FIG. 1, 21 is an insulating substrate such as a glass plate that is part of the vacuum envelope, and 22 is a vertical scanning electrode provided on this insulating substrate 21. This vertical scanning electrode 22 is formed by photoetching a transparent conductive film or a conductive film such as a metal film into a divided pattern. 23 is a linear cathode, and an oxide cathode is formed on the surface of a thin metal wire such as tungsten. 24 is a GI electrode for extracting electrons emitted from the heated linear cathode 23, and an opening 25 is formed at a position corresponding to the vertical scanning electrode 22.

The electrode width a of the vertical scanning electrode 22 is equal to the width of the opening 2 of the G1 electrode 24.
The vertical aperture length of No. 5 is smaller. By reducing the electrode width G of the vertical scanning electrode 22 and the vertical opening length of the opening 25 of the electrode 24, the potential gradient between adjacent electrodes of the vertical scanning electrode 22 becomes small, and the vertical scanning electrode Even if a vertical displacement occurs in the positional relationship between the 22 and 01 electrodes 24, the influence on the trajectory of the electron beam emitted from the linear cathode 23 is reduced. According to the trajectory calculation of the electron beam, the electrode width a of the vertical scanning electrode 22 is G,
By making the vertical aperture lengths of the electrodes 24 similar, the error on the faceplate is improved by about 20% when the vertical scan electrodes 22 are offset compared to the case where they are equal. Therefore, a higher quality image can be obtained to the extent that the error is improved, and conversely, the positional accuracy of the vertical scanning electrode 22 and the 01 electrode 24 can be relaxed within a range that does not affect the image quality. become.

Effects of the Invention As described above, in the present invention, by making the electrode width of the vertical scanning electrode smaller than G and the vertical opening length of the electrode, even if a positional shift occurs between the vertical scanning electrode and the 01 electrode, the line can be maintained. This reduces the influence on the trajectory of the electron beam emitted from the strip cathode, and it becomes possible to reduce the positional accuracy of the vertical scanning electrode, G, and electrode.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view of a vertical scanning electrode section in an embodiment of a flat cathode ray tube according to the present invention, FIG. 2 is a perspective view showing the overall configuration of a conventional flat cathode ray tube, and FIG. 4 is a perspective view of the vertical scanning electrode section of the flat picture tube of FIG. 2; FIG. 5 is a waveform diagram illustrating the operation of the vertical scanning electrode section of FIG. 4; The figure is a block diagram of the signal processing system of the flat picture tube in Figure 2, Figure 7 is a waveform diagram explaining the operation of the configuration in Figure 6, and Figure 8 is the vertical scanning electrode section of the flat picture tube in Figure 2. FIG. 21... Insulating substrate, 22... Vertical scanning electrode, 23...
...Striated cathode, 24...G, electrode, 25...opening, 102...face plate, 115...fluorescent material, 116...metal back electrode. Name of agent: Patent attorney Satoshi Nakao and one other person Figure 1, Figure 2, I Scanning Electronic @@ Figure 3, Figure 5, 103y ------J L-11 No. 8 figure

Claims (1)

[Claims] (1) Inside a vacuum container, there is at least a filamentary cathode, a divided electrode divided into a plurality of parts on the side opposite to the image display area with the filament cathode sandwiched between them, and an open electrode at a position opposite to the divided electrode on the side of the image display area. 1. A flat cathode ray tube characterized in that an electron beam extraction electrode having a hole is disposed, and the electrode width of the divided electrode is narrower than the aperture length of the electron beam extraction electrode.