JPS63105448A - Graphic fluorescent character display tube - Google Patents

Abstract

PURPOSE:To prevent a vibration of a linear grid perfectly and to prevent a lack of display and the like, even though a large size of graphic fluorescent character display tube with a linear grid is used, by forming a semiconductor membrane at least over the surface of projections of a base plate. CONSTITUTION:When a grid voltage is applied to a linear grid 6, the linear grid 6 is liable to vibrate by an electrostatic attraction between linear grids or an external shock, but since the linear grid 6 contacts projections 6 furnished between belt-formed anodes 5, the vibration can be prevented perfectly. Moreover, since a semiconductor membrane 9 is furnished on the surface of the projections 8, and the membrane 9 is connected electrically to an anode conductor 5a which is connected to a power source, the electrons flowing in the surface of the projections flow to the power source through the semiconductor membrane 9 and the anode conductors 5a. Therefore, the electron beams from a filament-formed cathode 7 are not charged up to the projections 8, and a trouble to lack a display owing to the charged-up electrons is eliminated perfectly.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a graphic fluorescent display tube for displaying characters and images, which is used in graphic display devices such as computer terminals and flat-panel televisions. The present invention relates to a graphic fluorescent display tube which has a structure in which a thin wire grid is stretched over an anode, is capable of preventing vibration of the linear grid, and has excellent display quality without display defects.

[Prior art]

Conventional graphic fluorescent display tubes often have a structure in which an XY matrix is formed by an anode coated with a phosphor layer and a grid. The grid shape may be mesh-like, thin wire-like, or plate-like with through holes.

A conventional graphic display tube having a structure in which a plurality of 1 m grids are stretched in parallel was filed by the present applicant and published in Japanese Utility Model Application No. 162692/1983, and its basic structure is well known.

The structure of the known graphic fluorescent display tube is as shown in a partially cutaway perspective view shown in FIG.

In the perspective view of FIG. 5, reference numeral 11 indicates a box-shaped envelope of the graphic fluorescent display tube. The envelope 11 includes an anode substrate 12 made of a glass plate, a back plate 13 provided facing the anode substrate 12, and an anode substrate 12 around the back plate 13.
The side plates 14 provided between the two are assembled and formed into a box-shaped sealed state using glass solder. and envelope 1
1, the gas inside the envelope 11 is exhausted from an exhaust pipe 15 provided on the back plate 13.

The exhaust pipe 15 is sealed and maintained in a high vacuum state.

Further, since the graphic fluorescent display tube shown in FIG. 5 is a front-emission type in which the luminescent display is observed from the direction of the arrow through the anode substrate 12, the anode substrate 12 needs to be translucent. A transparent strip-shaped anode conductor 16 is provided on the anode substrate 12.
form a. The method for forming the anode conductor is to apply a transparent FTT film of indium oxide mixed with tin oxide to the entire surface of the substrate by sputtering or electron beam evaporation, and then apply it using photolithography. A band-shaped anode conductor 16a is formed, and this anode conductor 16
A phosphor layer 16b is deposited on the substrate a by a well-known deposition method such as an electrodeposition method or a printing method. The anode conductor 16a and the phosphor layer 16b constitute an anode 16. The end of the anode 16 is.

Anode lead 19 sandwiched between anode substrate 12 and side plate 14
is electrically connected to. And the other end of the anode lead is
An anode lead 19 is formed outside the envelope 11 and extends in the vertical direction in FIG.

Further, above the anode 16, a plurality of linear grids 17 made of thin metal wires are stretched in parallel.

This linear grid 17 is arranged perpendicularly to the arrangement direction of the anodes 16, and the anode 16 and the linear grid 1
7 constitutes an XY matrix.

Furthermore, a filament-shaped cathode 18 is stretched above and away from the linear grid 17. Filamentary cathode 18
are composed of a plurality of pieces, which are parallel to each other and arranged in a fixed direction (in the embodiment shown in FIG. 5, in the same direction as the anode 16).

A grid lead 20 is held between the substrate 11 and the side plate 14 in the direction in which the linear grid 17 extends.

Reference numerals 21 designate external terminals of the filamentary cathode 18 that are arranged near the four corners of the envelope 11 and electrically connected to the filamentary cathode 18 .

22 is a spacer for stretching and arranging the linear grid 17 at a certain distance from the anode 16.

Since the conventional graphic fluorescent display tube is constructed as described above, its operation will be explained next.

A cathode voltage is applied to the external terminal 21 of the cathode 18 to cause the filamentary cathode 18 to emit electrons. When a positive grid voltage is applied to two adjacent linear grids 17, the emitted electrons are attracted to the linear grids and
It passes between the linear grids of books and heads toward the anode 16. positive vi
16 are arranged in a direction perpendicular to the linear grid 17 as described above, so the portion of the strip-shaped 1'A pole 16 surrounded by the two linear grids 17 has a plurality of dot-shaped pixels. becomes.

Therefore, when a 7-node voltage is applied to the band-shaped anode 16 for emitting light, electrons strike the part of the band-shaped anode surrounded by the two linear grids 17, producing a light-emitting display.

Graphic display is thus possible by scanning and applying the grid voltage to two adjacent lines of the linear grid 17 in a time-sharing manner and applying the anode voltage to the strip anode in synchronization with this grid voltage. .

Therefore, the position of one pixel is, for example, X in FIG.
The direction is fixed because it is determined by the position of the strip anode 16, but the Y direction is determined by the positions of two adjacent linear grids perpendicular to the strip S pole 16.

Therefore, to further explain the linear grid 17 in detail, the material of the linear grid 17 is a thin metal wire because it requires conductivity. Since the Fli is fixedly fixed, it is necessary that the coefficient of expansion is almost equal to that of the glass. -For example, 4 made of Ni, Cr, and Fe.
26 alloy (42% Ni, 6% Cr, remainder Fe).

The wire diameter of the linear grid 17 is generally a thin line of 0.15 to 0.3 strokes in order to increase the dot density, and its length is determined by the width of the envelope 11, but recently large displays are required. 15
It exceeds 0ma+ and is 200 to 2501m.

Next, the arrangement pitch interval of the linear grid 17 is
6, and are stretched in parallel with a pitch of, for example, 0.3 nm. If the horizontal arrangement pitch interval is not constant, the size of each pixel will not be constant and the display quality will deteriorate.

Furthermore, it is well known that the distance between the linear grid 17 and the anode 16 affects the luminance of the phosphor layer 16b, so in order to keep the distance from the anode 16 constant, the spacer 22 is
Provided near the envelope 11 of the linear grid 17.

It was fixed by applying tension. However, there was a limit to the tension due to the small diameter of the wire.

As a result, the linear grid 17 vibrates in the horizontal direction due to external shocks, electrostatic attraction generated when a grid voltage is applied, and the like. In addition, vibrations were also generated in the vertical direction due to the electrostatic attraction between the grid and the anode. That is, the horizontal vibration causes the pixel position to change, causing flicker, and the vertical vibration causes the brightness to change, causing flicker.

Therefore, the present applicant has applied for an invention to solve the above-mentioned problems in Japanese Patent Application No. 60-91376. As shown in Fig. 4, a plurality of band-shaped anodes each having a phosphor layer coated on a substrate are arranged in a stripe pattern, and a plurality of anodes are strung in a direction perpendicular to the anodes above the anodes. In a graphic fluorescent display tube in which a filament-like cathode and a filament cathode are arranged in an envelope kept in a vacuum, a plurality of anodes are arranged in the anode array gap on the substrate, the surface of which is located higher than the surface of the phosphor layer. This is a graphic fluorescent display tube characterized by having a convex portion.

In this manner, since the convex portion was provided and the vibrating linear grid 17 was brought into contact with the convex portion, vibrations were almost prevented.

However, the convex portions were formed by applying a paste-like mixture of low-melting-point glass as a main component and black pigment and organic solvent using a screen printing method, and baking the material at 350 to 500° C. to fix the material. Therefore, since the convex portion is insulative, electrons from the cathode are charged onto the surface of the convex portion.

Then, the trajectory of the electrons from the cathode is repelled and bent as shown in FIG. 4, and a phenomenon occurs in which there is a part at the corner of the anode where the electrons do not strike. Therefore, in the prior application, the height of the convex portion was set to such a level that even if charge-up occurred, display defects were not noticeable, that is, 1/3 or less of the pitch interval of the anodes. For this reason, there are some embodiments in which the linear grid and the convex portion are separated from each other, and although vibrations occur within that space, the vibrations are not large and flicker can be prevented to some extent.

Further, in order to completely eliminate vibrations, there are some embodiments in which a linear grid is stretched low and in contact with the upper surface of the convex part, or is bonded to the convex part. However, even in this embodiment, the problem of charge-up on the surface of the convex portion could not be completely solved.

Therefore, as a conventional charge-up prevention method, a conductive insulating paste was created by mixing particles such as titanium oxide and tin oxide into an insulating paste whose main component was low-melting frit glass. Attempts have been made to form conductive crossover layers by deposition and subsequent firing.

However, when mixing conductive metal oxide particles into an insulating paste, it is not easy to mix the particles uniformly. Therefore, the sheet resistance of the formed conductive crossover layer is difficult to be constant, and it is not easy to control the resistance value.

Furthermore, since fine patterns cannot be created with thick film printing, a paste is created by adding a photosensitive material to the paste mixed with the conductive particles, and after coating the entire surface with thick film printing, photolithography is performed. Even when used in a thick-film photolithography method in which patterning is carried out using the method, the conductive particles have a problem in that the conductive particles adversely affect the exposure conditions, making pattern formation difficult.

[Object of the present invention]

Therefore, in the present invention, if the insulating layer forming the convex part is composed of an insulating paste mainly composed of low-melting frit glass, and the surface of the insulating convex part is coated with a semiconductive thin film,
It is thought that the resistance value can be made uniform, so even if it is a large graphic fluorescent display tube using a linear grid,
It is an object of the present invention to provide a graphic fluorescent display tube which can completely prevent vibration of a linear grid and has excellent display quality without display dropouts.

[Structure of the invention]

In order to achieve the above-mentioned object, the present invention has a structure including a box-shaped envelope whose inside is kept in a vacuum, an anode conductor in a stripe shape on a substrate in the envelope, and a phosphor on the anode conductor. a strip anode consisting of a layer, a convex portion disposed near the strip anode so that its upper surface is higher than the surface of the phosphor layer, and a plurality of linear anodes stretched in a direction perpendicular to the strip anode. A graphic fluorescent display tube comprising a grid and a filamentary cathode stretched above the linear grid,
A semiconductive thin film is formed on at least the surface of the convex portion on the substrate.

[For production]

As mentioned above, the fluorescent display tube of the present invention can be grounded by forming a semiconductive thin film on the surface of the convex part and connecting this semiconductive thin film to the anode conductor or by providing an independent lead. It has the effect of preventing electron charging and preventing the phenomenon of anode display failure due to charge-up. Further, if the height of the convex portion is set to such a height that the linear grid and the convex portion are always in contact with each other, both vertical and horizontal vibrations can be completely prevented.

〔Example〕

Embodiments of the present invention illustrated in the drawings will be described below.

FIG. 1 and FIG. 2 are cross-sectional views showing Example 1, which is an example in which a semiconductive thin film was formed only on the surface of the convex portion. FIG. 3 is a cross-sectional view showing Example 2 in which a semiconductive thin film was formed on the convex portion and the anode conductor, that is, on the entire display portion.

Embodiment 1 FIG. 1 is a sectional view of a graphic fluorescent display tube (hereinafter abbreviated as a fluorescent display tube) of the present invention, and FIG. 2 is an enlarged sectional view of a part thereof.

In the figure, 1 is an envelope of a fluorescent display tube, which includes an anode substrate 2,
It has a box-like structure including a back plate 3 facing an anode substrate 2 and a side plate 4 interposed therebetween.

The inside of this envelope 1 is maintained at a high vacuum, and electrodes such as an anode 5, a grid 6, a cathode 7, and a convex portion 8 are arranged.

In general, fluorescent display tubes are of a front-emission type, in which the luminescent display at the anode 5 is observed through an anode substrate 2, or a front panel (corresponding to the rear panel 3 in Fig. There is a type that observes things through Although the present invention can be applied to any type, in this embodiment, a front-emission type will be explained.

In the front-emitting type, the anode substrate 2 needs to be translucent so that the display can be seen. Furthermore, since insulation is also required, a glass substrate is generally used.

An ITOM film is deposited over the entire surface of the anode substrate 2 by sputtering, vapor deposition, etc., and strip-shaped anode conductors 5a are formed in stripes with a pitch of about 0.3 mm by means of photolithography. 110w used for this anode conductor
The membrane is 0.1-0.2 μm thick and has a sheet resistance of 5
It is a type of transparent conductive film with a resistance of 0Ω/hole. Each anode conductor 5a
The end portion of the anode conductor 5a is electrically connected to an anode lead (not shown) as in the conventional example, so that an anode voltage can be applied to each anode conductor 5a.

Next, a photosensitive material is mixed in a black paste containing low-melting glass as a main component on the anode substrate 5a and on the anode substrate between the strip anode conductor 5a and the adjacent strip anode conductor 5a, that is, on the entire display area on the substrate 2. After the paste is applied to the entire surface by a printing method, striped convex portions are formed between the strip-shaped anode conductors by a photolithography method. Thereafter, a final firing process is performed at 350 to 550° C. for 10 minutes to evaporate the solvent and the like in the paste material and fix the convex portions 8. The height of the convex portion 8 is set to be 30 to 50 μm higher than the substrate 2.

Next, ITO9117J9 containing SnO2 in In,03 is deposited on the surface of the convex portion by a printing method. This TO thin film forming liquid is a low viscosity liquid in which an organic stannous compound and an organic indium compound are dissolved in an organic solvent.

When this thin film forming liquid is applied to the convex part 8 side of the substrate 2 using a roll coater, the thin film forming liquid adheres to the surface of the convex part and a part of it flows along the side surface 8a of the convex part 8. It will also be covered. After deposition, the organic metal is thermally decomposed by heat treatment in a firing furnace to form an In2O thin film (ITO thin film) 9 containing about 5% SnO. Therefore, the end portion of the ITO thin film 9 formed on the side surface 8a of the convex portion.

It will be connected to the anode conductor 5a. The sheet resistance of the ITO thin film 9 formed on the surface of the convex portion 8 is 1×10 6 ~l
X101sΩ/mouth, and is a thin film having semiconductivity.

A phosphor layer 5b is formed on the anode conductor 5a of the substrate 2 on which a semiconductive ITO thin film 9 is formed on the surface of the convex portion 8.

The phosphor layer 5b is formed on the surface of the strip-shaped anode conductor 5a by a well-known electrodeposition method or printing method.

The anode 5 is constituted by the phosphor layer 5b and the anode conductor 5a.

Above facing the anode 5, a linear grid 6 is stretched at a constant height by contacting the upper surface of the spacer 10 provided near both ends of the anode substrate 2, and is sandwiched between the side plate 4 and the anode substrate 2. It is fixed with bamboo sealing material made of low melting point glass. Similar to the conventional example shown in FIG. 5, this linear grid 6 is stretched in parallel in a direction orthogonal to the band-shaped anodes 14i5 at a pitch of 0.3 am, which is approximately the same as the anode pitch. The ends of the linear grids 6 extend outside the envelope 1 as grid leads 6a. Thus, the configuration is such that a grid voltage can be applied to each linear grid from the grid leads 6a.

Above the linear grid 6 is a filamentary cathode 7.
A plurality of the anodes are stretched in a direction perpendicular to the linear grid 6, that is, in the same direction as the strip anodes 5.

Here, the semiconductive thin film, which is the gist of the present invention, will be described in more detail.

The semiconductive thin film has a sheet resistance of lXl×105 to 1×1
It suffices if it is a thin film of a substance in the range of ×105Ω/mouth
Examples include sb-doped SnO film, commonly known as Nesa film, Indium mixed with SnO□, 0.0. There are thin films generally known as ITO films.

In this embodiment, a case will be described in which the latter ITO film is used.

There are various methods for forming this IT○ film, such as vapor deposition, sputtering, CVD, roll coater, depping, and printing. Next, the thin film forming liquid has the general formula In(OCOR)n (Cs Hv 02)a-n (
R is an alkyl group, n is an integer of 1 to 2), and an organic indium compound represented by the general formula Sn (OCOR)n (CsH
An organic stannous compound represented by yOx)J-n is mixed. The mixing ratio is that when In263 and SnO are changed to oxide, In and O are 95% in the mixed oxide.
The organic metals are mixed so that they contain 5% of SnO and SnO.

In general, ITO is a substance containing 95% In, O, and 5% SnO□? The ITO thin film is used as a 4-layer film, but if ZrO is further added to this by about 1θ%, the strength of the ITO thin film increases and a transparent conductive film with 1-toughness can be obtained.

To obtain an ITO thin film containing ZrO, about 10% of an organic compound of Zr is mixed in the ITO thin film forming solution. A mixture of carboxylic acid and acetylacetone as a low solvent, and a hot material such as alcohol ketones or esters as a concentration adjusting agent are also mixed as necessary to form a thin film forming liquid.

The thin film forming liquid 24 is placed in a tray 23 of a single roller 25 type roll coater D as shown in FIG.
An ITO thin film is deposited on the side of the glass substrate 2 on which the convex portions 8 are provided. Note that 26 is a transfer roller that transfers the substrate 2;
7 is a floating prevention ring. 8 After being adhered, heat treatment is performed with the adhered surface facing upward.

Then, a part of the thin film forming liquid that had adhered to the upper surface of the convex portion flows to the side surface of the convex portion, and also adheres to the side surface 8a of the convex portion.

Next, the operation of the fluorescent display tube of the present invention will be explained.

When a cathode voltage is applied to the filamentary cathode 7, electrons are emitted. The emitted electrons are transferred to two linear grids 6 to which a positive grid voltage is applied to adjacent linear grids 6.
The light is directed toward the anode 5 from between the two and strikes the phosphor layer 5b of the band-shaped anode 5 to which a positive anode voltage has been applied, causing the phosphor layer 5b to emit light. When a grid voltage is applied to the linear grid 6 in this way, vibrations are likely to occur in the linear grid 6 due to electrostatic attraction between the linear grids or external shocks, but the linear grid 6 of the present invention , since it is in contact with the convex portion 8 provided between the strip anodes 5, vibration can be completely prevented.

Further, a semiconductive thin film 9 is provided on the surface of the convex portion 8 and is electrically connected to the anode conductor 5a, and since the anode conductor 5a is connected to a power source, the electrons flowing into the surface of the convex portion are semiconductive. The current flows to the power source through the conductor and the anode conductor. Therefore, since the electrons from the filamentary cathode do not jump up to the convex portion 8, the problem of display defects caused by charged-up electrons as shown in FIG. 4 is completely eliminated.

Embodiment 2 FIG. 3 is an enlarged sectional view of a second embodiment of the fluorescent display tube of the present invention. The formation of the band-shaped anode conductor 5a and the convex portion 8 on the anode substrate 2 is the same as in the first embodiment, and the explanation will be omitted.
The strip-shaped anode conductor 5a and the substrate 2 on which the strip-shaped protrusions 8 are arranged are coated on the anode conductor 5a and on the substrate 2 on the protrusions 8 by a vapor phase plating method such as vapor deposition, sputtering, or CVD.
A semiconductive thin film 9 made of an ITO thin film is formed on the entire surface. The thickness of the semiconductive thin film 9 is 1000 Å or less, and the sheet resistance of the thin film can be used if it is within the range of lXl0'' to lXl0'' Ω/mouth, but preferably lXl0'' to 1×1
Good light emission can be obtained in the range of 0uQ1.

Next, a phosphor layer 5b is formed on the anode conductor 5a by a well-known deposition method such as electrodeposition or printing. Therefore, in the anode 5, a semiconductive thin film 9 is interposed between the anode conductor 5a and the phosphor layer 5b.

Since the thickness is 1000 Å or less, the resistance in the thickness direction is very low, and even if the semiconductive thin film 9 is completely deposited on the anode conductor 5a, the voltage drop in the anode voltage is minute.

It does not significantly affect the light emission of the phosphor layer. Also, the convex portion 8
Electrons charged on the surface of the semiconductive thin film 9 are transferred to the anode conductor 5.
Since it is connected to a, it will flow into the anode conductor. As a result, the convex portion 8 is no longer charged with electrons, and the charged electrons can prevent the trajectory of the electrons from the cathode from being bent, thereby eliminating the drawback that the display of a part of the anode 5 is missing.

〔effect〕

As explained above, the present invention forms a plurality of convex portions near the anode and at a higher position than the anode on the anode substrate facing the linear grid, and a semiconductive thin film is disposed on the surface of the convex portions. This has the following effects.

(1) The linear grid is placed on a convex part to prevent the linear grid from vibrating due to an external shock or electrostatic attraction generated when a voltage is applied between the anode and the grid or between adjacent grids. By making contact, vibration can be completely prevented. Therefore, the linear grid and anode contact and short-circuit. Disconnection of linear grid,
This has the effect of preventing the anode from burning out.

(2) In addition, since the vibration of the linear grid can be prevented, it is also possible to prevent flickering due to fluctuations in pixel position caused by this vibration and flickering due to changes in brightness, making it possible to display graphics with excellent display quality. has.

(3) Since a convex portion is provided close to the anode and a semiconductive thin film is formed on the surface of this convex portion, there is no charge of electrons on the convex portion, and the defect of display defects due to charged electrons is completely eliminated, improving display quality. This has the effect of providing an excellent graphic fluorescent display tube.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a graphic fluorescent display tube of the present invention;
FIG. 2 is a partially enlarged sectional view of FIG. 1, FIG. 3 is a partially enlarged sectional view of another embodiment of the present invention, and FIG. 4 shows the trajectory of electrons in a conventional graphic fluorescent display tube. FIG. 5 is a partially cutaway perspective view of a conventional graphic fluorescent display tube, and FIG. 6 is a schematic diagram of a single-roller type roll coater. 1... Envelope 2... Anode substrate 3...
... Back plate 4 ... Side plate 5 ... Anode 5a ... Anode conductor 5b ... Phosphor layer 6 ... Linear grid 7 ... Filament-shaped cathode 8... Convex portion 9... Semiconductive thin film patent applicant Futaba Electronics Co., Ltd. ■ M 2 Figure 3 Figure 4

Claims (3)

[Claims] (1) A box-shaped envelope whose interior is kept in a vacuum, a strip-shaped anode consisting of a striped anode conductor on a substrate in the envelope and a phosphor layer on the anode conductor, and the strip-shaped anode A convex portion disposed nearby so that its upper surface is higher than the surface of the phosphor layer, a plurality of linear grids stretched in a direction perpendicular to the strip anode, and a plurality of linear grids stretched above the linear grid. What is claimed is: 1. A graphic fluorescent display tube having a filament-like cathode provided thereon, characterized in that a semiconductive thin film is formed on at least the surface of the convex portion on the substrate. (2) The graphic fluorescent display tube according to claim 1, wherein the semiconductive thin film is disposed on the surface of the convex portion and the anode conductor. (3) The sheet resistance of the semiconductor electrode thin film is 1×10^5
3. The graphic fluorescent display tube according to claim 1 or 2, wherein the resistance is in the range of 1×10^1^5 Ω/b.