JPH01176640A - Display device of flat plate type - Google Patents

Abstract

PURPOSE:To prevent a linear cathode from producing vibration by forming an insulation film of a shape having regular projections and depressions on a insulation supporting body and disposing the linear cathode stretched in contact with the surface of the projections. CONSTITUTION:Forming an insulation film 8 on vertical scanning electrodes 7 disposed in electrically separated condition on an insulation support body 6, a linear cathode 9 is laid directly on the insulation film 8. The insulation film 8 laid on the vertical scanning electrodes 7 becomes of the shape having regular projections and depressions on the insulation body 8 by the thickness of the vertical scanning electrode 7 with its projections coming into contact with the linear cathode 9. This makes it possible to maintain the distance between the linear cathode 9 and the vertical scanning electrodes 7 constant as well as to prevent the vertical scanning electrodes 7 from short-circuiting electrically with each other and prevents the linear cathode 9 from producing vibration.

Description

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

2. Description of the Related Art Recently, thin display devices have been widely used in the field of displaying images, characters, and the like.

These thin display devices include flat picture tubes.

The present applicant previously proposed a flat picture tube in Japanese Patent Laid-Open No. 189848/1989 and Japanese Patent Laid-open No. 193242/1986.

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 images, characters, etc. are displayed, a horizontal direction H and a vertical direction Y are illustrated on the face plate portion. Vertically long linear cathode 1o1
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 1o1 and the spacing between them are arbitrary. For example, if the display screen size is 10 inches, the spacing between the linear cathodes 1o1 and 20 linear cathodes 1o1 is approximately 1 eomm in the vertical direction. It is arranged with a length of . A face plate portion 1 which is a screen portion separated from the linear cathode 101 so as to sandwich the linear cathode 1o1.
02, and the vertical scanning electrode 1 adjacent to the linear cathode 101.
03 is placed. The vertical scanning electrodes 103 are elongated in the horizontal direction, have equal pitches, are electrically divided, and are supported on an insulating support 104. These vertical scanning electrodes 103 are formed as independent electrodes having the same number of horizontal scanning lines in the vertical direction (approximately 480 in the NTSO system) if, for example, a normal television image is to be displayed. Note that the number of vertical scanning electrodes 103 may be 1/the number of horizontal scanning lines.

Between the linear cathode 101 and the face plate 102, one grid electrode (
1o5 (hereinafter referred to as the G1 electrode), a second grid electrode (hereinafter referred to as the G2 electrode) 106, a third grid electrode (hereinafter referred to as the G3 electrode) 107, and a fourth grid electrode (hereinafter referred to as the G4 electrode). 108 are arranged. The number of electrodes is a design matter and is not limited to the number. Gl electrode 1
Each of the electrodes from 06 to G4 electrode 108 has an opening for passing the electron beam in a portion corresponding to the linear cathode 1o1. The Gl electrode 106 is electrically divided into individual linear cathodes 101, and a video signal is applied to each electrode to perform beam modulation for each linear cathode 101. The G2 electrode 106 to the 04 electrode 10B are planar electrodes for extracting the electron beam or optimizing the spot diameter of the beam in the horizontal and vertical directions. A horizontal deflection electrode 113A111 is provided between the G4 electrode 108 and the face plate 1020.
3B and 113C are arranged symmetrically with respect to the straight axis of the electron beam from each linear cathode 101 and at the same spacing as the linear cathode spacing. Each horizontal deflection electrode 113A, 113B
, 113C forms a conductive film on the surface of the insulating support 1140 by plating, vacuum deposition, or the like.

An optimal DC voltage for optimizing the horizontal spot diameter of each electron beam and a deflection voltage for horizontally deflecting each electron beam are applied to each of the horizontal deflection electrodes 113A, 113B, and 113C. A light emitting layer consisting of a phosphor 116 and a metal back electrode 116 is formed on the inner surface of the face plate 1o2. The phosphor 116 is formed as red (1'L), green (G), and blue (B) stripes or dots in the horizontal direction in order for color display.

Next, the operation of the flat picture tube described above will be explained. First, a current is passed through the linear cathode 101 to heat it and
Approximately the same voltage as that of the linear cathode is applied to one electrode 105 and one vertical scanning electrode 1o3 (one horizontal scanning line). At this time, the electron beam advances from the linear cathode 101 toward the Gl electrode 106 and the G2 electrode 106, and each electrode 106
5. A voltage higher than the potential of the linear cathode 101 (1o
0 to about 500 V) is applied to the 02 electrode 106. Here, the electron beam can be controlled by modulating it by applying a potential more negative than the potential of the linear cathode 101 to the Gl electrode 105. The electron beam passing through the aperture of the G2 electrode 106 is transferred to the G3 electrode 107, the G4 electrode 108,
Horizontal deflection electrodes 113A, 1 facing each other across the electron beam
13B and 1130, a predetermined voltage is applied to these electrodes so that the electron beam diameter becomes a small spot on the fluorescent surface. Here, horizontal deflection electrodes 113A, 113B
, 113'O are applied with individual DC voltages to obtain the best spot diameter, and at the same time, deflection voltages such as sawtooth waves, step waves, or triangular waves with a horizontal scanning period are simultaneously superimposed. The electron beam is horizontally deflected with a predetermined width.

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 116 as described above, each color is applied to the Gl electrode corresponding to the phosphor of each color on which the electron beam is incident. It is sufficient to apply a modulation signal of In addition, in the vertical scanning in this method, an electron beam is applied to each of the vertical scanning electrodes 103 provided on the back surface of the linear cathode 101 sequentially from the top for one horizontal scanning period (IH). Vertical scanning can be performed by applying a potential such as that generated on the 116 side.

Problems to be Solved by the Invention However, the above configuration is fine when the screen to be displayed has a small area, but as the area increases, the linear cathode becomes longer and the linear cathode and vertical scanning electrode, and Gl
It is difficult to maintain a uniform distance between electrodes over the entire area. Further, as shown in FIG. 7, the linear cathode 1o1 is fixed at one end to a fixing pedestal 117 by means such as welding on an insulating support 104 provided with a vertical scanning electrode 103, and the other end is It is stretched by a spring 118 and placed at a constant distance from the vertical scanning electrode 103. The linear cathode 101 is made of a thin metal wire with a diameter of 10 to 50 μm coated with an oxide cathode, and is supported at both ends. Since the linear cathode 101. ! : An electrical short circuit will occur with the vertical scanning electrode 103 or the G1 electrode, and the linear cathode will be damaged. Further, the vibration of the linear cathode heats the linear cathode and destabilizes the amount of electrons generated, which causes brightness to vary on the screen.

The present invention solves the above problem and aims to prevent vibrations of the linear cathode.

Means for Solving the Problems In order to prevent the vibration of the linear cathode, which is the above-mentioned problem, the present invention provides an insulating thin film on vertical scanning electrodes that are electrically divided and provided on an insulator. A linear cathode is placed directly on this insulating film. The insulating film provided on the vertical scanning electrode has a concave and convex shape on the insulator corresponding to the thickness of the vertical scanning electrode, and the convex portion comes into contact with the linear cathode. With this structure, one direction of the linear cathode is supported by a rigid body, so the present invention achieves the above object. Prevent the occurrence of electrical short circuits between electrodes and vibration of the linear cathode, and reduce the increase in power applied to the linear cathode as much as possible.

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

FIG. 1 is a partial configuration diagram of a linear cathode portion of a flat cathode ray tube for explaining a first embodiment of the present invention.

In FIG. 1, 6 is an insulating support such as a glass plate, 7 is a vertical scanning electrode provided on the insulating support e, an insulating film 8 is provided on the vertical scanning electrode 7, and an insulating film 8 is provided on the insulating film 8. A linear cathode 9 is placed in contact with the insulating film 8 . The configuration from this linear cathode part to the face plate is as shown in FIG.
Since the configuration is the same as the previous configuration, illustration is omitted.

A vertical scanning electrode 7 is provided on an insulating support e made of a glass plate for switching electrons generated by heating a linear cathode 9 in a direction perpendicular to the screen. The vertical scanning electrode 7 is made of a conductive thin film, and is formed by screen printing, photoetching, etc. in the form of an elongated electrode in the horizontal direction of the screen and divided in the vertical direction, and has a thickness of about 0.1 to 2 μm. . Next, a heat-resistant insulating film 8 is formed on the insulating support 6 and the vertical scanning electrode 7 so as to cover the entire surface. Insulating film 8 is 5i02, AI
203, etc., to a thickness of about 0.5 to 6 μm by means such as vacuum evaporation, sputtering, and OVD. The insulating film 8 is formed with an uneven surface due to the thickness of the vertical scanning electrode 7 formed on the insulating support 6.

A linear cathode 9 is disposed on this insulating film 8 in contact with the insulating film 8, with both ends stretched by springs as in FIG. Usually, the linear cathode 9 is a metal wire 91 made of tungsten with an oxide cathode 92 coated on the surface thereof, and is heated to about 700° C. to emit electrons. However, at this time, due to the coefficient of thermal expansion of the tungsten wire 91, elongation occurs in the stretching direction.

As a result, due to the repeated heating and non-heating operations of the linear cathode 9, the linear cathode 9 and the insulating film 8 rub against each other, and a portion of the oxide cathode 92 of the linear cathode 9 is exposed to the tungsten wire 91. It becomes difficult to separate from above and emit --like electrons as the linear cathode 9. Therefore, this problem can be solved by removing a portion of the oxide cathode 92 corresponding to the insulating film 8 side of the linear cathode 9 to expose the tungsten wire 91. can.

FIG. 2 shows a second embodiment. As shown in the figure, a curved surface that is convex toward the linear cathode 9 is insulated and supported so that the linear cathode 9 and the insulating film 8 maintain stable contact over the entire length of the linear cathode 9. You can also process the body 6 to have a lower front. Furthermore, as another means for obtaining this effect, mechanical pressure may be applied to the insulating support 6 to give it a curved surface with a predetermined curvature. Alternatively, a curved surface may be formed by sequentially changing the film thickness of the vertical scanning electrode 7 and/or the insulating film 80 in the length direction of the linear cathode 9.

Next, as a third embodiment of the present invention, a linear cathode section shown in FIG. 3 will be described. In the embodiment shown in FIG. 1, the insulating film 8 provided between the vertical scanning electrode 7 and the linear cathode 9 is formed uniformly over the entire surface, and depending on the thickness of the vertical scanning electrode 7, the insulation film 8 on the linear cathode 9 side is formed uniformly over the entire surface. The structure in which unevenness is formed on the surface of the insulating film 8 has been described, but as shown in FIG. 3, the vertical scanning electrode 7 is formed on the insulating support e, and the insulating film is A film 8 may also be formed.

At this time, the insulating film 8 is formed so as to partially cover the vertical scanning electrode 7 . Due to this structure, the insulating film 8 has a convex portion on the vertical scanning electrode 7, and the linear cathode 9 contacts with this convex portion, and does not contact the linear cathode 9 at the vertical scanning electrode 70 divided portion. The state will be as follows. As a result, the contact area between the linear cathode 9 and the insulating film 8 can be made smaller than in the embodiment shown in FIG. 1, so that the heating power for the linear cathode 9 can be reduced.

Furthermore, in the structure described in the embodiment of FIG. 1, the structure shown in FIGS. 4 and 5 will be described as a fourth embodiment of the structure for reducing the contact area between the linear cathode 9 and the insulating film 8. In FIG. 4, the vertical scanning electrode 7 provided on the insulating support 6 has a linear cathode 9 (not shown) in each of the vertical scanning electrodes 7 which are divided and arranged as shown in FIG. A groove 1o is formed in the length direction of the vertical scanning electrode 7 at least at opposing positions.

This groove 1o can be easily formed by photoetching at the same time as the vertical scanning electrode 7 is processed. Returning to Figure 4,
An insulating film 8 is formed over the entire surface of the vertical scanning electrode 7, and a linear cathode 9 is disposed on the insulating film 8 in contact with the insulating film 8, being stretched by a spring (not shown). be done. Here, the insulating film 8 has unevenness caused by the difference in thickness due to the 1° groove provided in the vertical scanning electrode 7, and the linear cathode 9 comes into contact with the convex portion. As a result, the contact area between the insulating film 8 and the linear cathode 9 can be reduced, and the electric power required to heat the linear cathode 9 can be reduced accordingly.

The present invention has been explained above using examples, but
The present invention is also applicable to display tubes using other linear cathodes. For example, the vertical scanning electrode may not be used as a vertical scanning electrode, but may simply be a modulation electrode, or
It does not need to be a divided electrode, and may have a structure in which the insulating support is exposed in a part of a single electrode. Further, the insulating film only needs to be provided at least at a position facing the linear cathode, and does not need to be provided on the entire surface of the insulating support.

Effects of the Invention As described above, the present invention provides a display tube using a linear cathode, in which a heat-resistant insulating film is formed on an insulating support on the surface opposite to the display area by sandwiching the linear cathode. By forming a linear cathode into a shape and stretching the linear cathode in contact with the convex surface, vibration of the linear cathode is prevented, and the electron beam generated by heating the linear cathode is stabilized. be able to. Furthermore, since only the convex portions of the insulating film that come into contact with the linear cathode come into contact with each other, heat loss when heating the linear cathode is relatively small. In addition, by removing one side of the linear cand that is in contact with the insulating film before removing the oxide cathode, peeling of the oxide cathode that occurs due to friction between the insulating film and the linear cathode can be avoided. (None).

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of a linear cathode portion of a flat panel display device for explaining a first embodiment of the present invention, and FIG. FIG. 3 is a cross-sectional side view of a linear cathode portion of a flat panel display device for explaining a third embodiment of the present invention, and FIGS. 4 and 6 are cross-sectional side views of a linear cathode portion of the present invention. A cross-sectional side view and a perspective view of the linear cathode portion of a flat panel display device for explaining the fourth embodiment, FIG. 8 is a perspective view showing the overall configuration of a conventional flat panel display device, and FIG. 7 is a conventional FIG. 3 is a perspective view of a linear cathode portion of the flat panel display device of FIG. 6... Insulating support, 7... Vertical scanning electrode, 8...
Insulating film, 9... Linear cathode, 91... Metal wire, 9
2...Oxide cathode. Name of agent: Patent attorney Toshio Nakao and 1 other person @1
Figure 2 Figure 3 Figure 4 □ Food book Figure 5

Claims (7)

[Claims] (1) disposing at least a linear cathode in a vacuum container;
A support on which an insulating film with an uneven surface is formed is disposed on one side of the linear cathode, and the linear cathode is stretched in contact with the convex portion of the insulating film. flat display device. (2) Claims characterized in that the support is formed with a conductive film that exposes a part of the insulating support, and further has an insulating film formed on part or the entire surface of the support. 2. The flat panel display device according to item 1. (3) The linear cathode is constructed by covering the surface of the metal wire with an oxide cathode, and at least on the side in contact with the insulating film,
Claim 1, characterized in that the oxide cathode is removed partially or over the entire length from above the metal wire.
The flat panel display device described in Section 1. (4) The flat panel display device according to claim 1, wherein at least the linear cathode is stretched over an insulating film with a predetermined curvature. (5) The flat panel display device according to claim 1, wherein the support on which the insulating film is formed constitutes a part of a vacuum container. (6) A divided electrode made of a conductive film is provided on the support substantially perpendicular to the linear cathode, and an insulating film is formed on a part or the entire surface of the divided electrode. A flat panel display device according to claim 1. (7) At least a part of the divided electrode is a flat plate according to claim 6, wherein a part of the divided electrode is removed at a position facing the linear cathode. Display device.