RU2253167C2 - Fluorescent-cathode matrix screen - Google Patents

Abstract

FIELD: display engineering; computer, radar, television engineering, and the like.

SUBSTANCE: proposed fluorescent cathode matrix screen or flat optoelectronic output has vacuum envelope with insulating base; sets of anode electrodes in the form of parallel phosphor-covered strips of at least one color applied to insulating base and connected by means of current-carrying tracks to external leads through contact pads; cathodes; control electrodes orthogonal to anode electrodes and forming at intersection light-emitting segments; emitter cathodes are made by carbon nanotubes applied to control electrodes for emitting electron stream when at least one control electrode out of aggregate of control electrodes is turned on during turn-on moment of respective anode electrodes. In addition, distance between planes of anode electrode and electrode-cathode-emitter control system, and potential difference across turned-on anode electrodes and electrode-cathode-emitter control system are interrelated by equation

where E is field intensity of electrode-cathode-emitter control system ranging between 1 and 20 V/μm; U'_a-cs-em is specified potential difference across turned-on anode electrodes and chosen turned-on electrode-cathode-emitter control system; X_a-cs-em is distance between planes of anode electrodes and electrode-cathode-emitter control system, μm; potential difference U"_a-cs-em for non-chosen turned-off electrodes, anodes, emitters of control system should range between 0 and ±0.75 U'_a-cs-em V.

EFFECT: enhanced reliability of screen and, hence, improved quality of displayed information.

2 cl, 2 dwg

Description

The invention relates to indicator technology, and more particularly to matrix cathodoluminescent screens or flat cathode ray tubes (CRTs) with an electrical input and optical output used in computing, radar, television, etc.

The cathodoluminescent matrix screen is a vacuum electronic device, a thermionic cathode, control grids and holders enclosed in a vacuum-tight shell with a board on which, according to a given pattern, conductive screen segments coated with a phosphor and conductive wiring with contact pads are placed. See Gorfinkel B.I., Abalduev B.V., Medvedev R.S., Loginov A.P. Low voltage cathodoluminescent indicators. M .: Radio and communications, 1983, p.112; Bystrov Yu.A., Persianov G.M. Sevostyanov Yu.S. Vacuum fluorescent indicators. - Reviews on electronic technology. Ser. 4, publishing house of the Central Research Institute "Electronics", issue 2 (885), 1982, p. 44.

Vacuum luminescent indicators (VLIs) are known, containing a vacuum cylinder in which a circuit board is placed with anode electrodes located on it that are coated with a phosphor, as well as a cathode, grids and external leads connected to the corresponding indicator electrodes (see L. Lisitsyn, Low-voltage indicators, 1985, pp. 101-105; Rusina EV, Matrix indicators on the panel based on low-voltage cathodoluminescence. Journal "Electronic Industry", No. 5-6, 1982, p. 88-89).

The disadvantages of these devices are the presence of a complex system of straight filament cathodes and, accordingly, the high consumed power of incandescent filament cathodes.

Known cathodoluminescent matrix screen containing the front plate and the substrate, a system of direct filament cathodes, rows of anode electrodes deposited on the substrate in the form of parallel strips coated with a phosphor of at least one color and connected by current-carrying tracks with external leads through contact pads, control electrodes, orthogonal anode electrodes and forming light emitting segments, a dielectric frame hermetically connecting the front plate and the substrate, the control electrodes are made in e edges and are arranged at a face on the dielectric layer deposited on a substrate, and anode electrodes at the intersections of the anode electrodes and the control electrodes, see RF patent №2173909, MKI:. H 01 J 31/12, publ. September 20, 2001

The disadvantage of this design is the complex system of control electrodes and direct cathodes, since in the case of using this device on large-sized substrates, the method of its manufacture is cumbersome and technologically uneconomical.

The closest analogue in technical essence to the proposed solution - the prototype is the design of the cathodoluminescent screen matrix type, described in RF patent No. 2173908, MKI: H 01 J 31/12, publ. 09/20/2001, containing a vacuum shell consisting of a front plate and an insulating base, a direct-heating cathode system, rows of anode electrodes deposited on an insulating base, made in the form of parallel strips coated with at least one color phosphor and connected by current-carrying paths with external leads through pads, a system of control electrodes orthogonal to the anode electrodes and forming light-emitting segments, a dielectric frame hermetically connecting the face plate and insulating th substrate between the anode electrodes are made of dielectric protrusions paste-barriers, wherein the system control electrodes disposed on the number of screen lines.

The disadvantage of this device is the unreliability of the structure due to the complex manufacturing technology of control electrode and cathode systems due to the large volume of installation work.

The invention is as follows. The task to which the invention is directed is to increase the reliability of the screen and, accordingly, the quality of the information displayed.

The specified technical result during the implementation of the invention is achieved by the fact that in a cathodoluminescent matrix screen containing a vacuum shell with an insulating base, rows of anode electrodes deposited on the insulating base in the form of parallel strips coated with a phosphor of at least one color and connected by current paths with external terminals through contact pads, cathodes, control electrodes orthogonal to the anode electrodes and forming light-emitting segments at the intersection, Nena applying carbon nanotubes to the control electrodes, with electron beam emittirovaniya when the at least one control electrode of a plurality of control electrodes at the moment when the respective anode electrodes.

In addition, the distance between the planes of the systems of anode electrodes and control electrodes-cathodes-emitters and the potential difference between the included anode electrodes and control electrodes-cathodes-emitters are related by the ratio

at E≅ from 1 to 20 V / μm, where

E is the field strength of the control electrode-cathode-emitter,

U ' _a-soup-um - the installed potential difference between the switched on anode electrodes and the switched-on selected control electrode-cathode-emitter,

X _a-soup-em - the distance (μm) between the planes of the anode and control electrodes-cathodes-emitters, while for disconnected unselected control electrodes-cathodes-emitters, the potential difference U '' _a-soup-em should be in the range from 0 to 0.75 U'a _-soup-em- volt.

Thus, in this technical solution, a control electrode with deposited nanotubes is used as a cathode-emitter, forming a new structural element: a control electrode-cathode-emitter.

The invention is illustrated by graphic materials, an example of a specific implementation and description.

Figure 1 schematically shows a cathodoluminescent matrix screen according to the claimed technical solution.

Figure 2 schematically shows a fragment of a cathodoluminescent screen: a top view of an insulating base with anode electrodes and control electrodes coated with nanotubes forming control electrodes-cathodes-emitters, and also a light-emitting segment is shown.

The following notation is accepted:

1 - vacuum shell

2 - insulating base,

3 - anode electrodes,

4 - phosphor,

5 - contact pads,

6 - external conclusions

7 - control electrodes-cathodes-emitters,

8 - carbon nanotubes,

9 - light emitting segments.

The cathodoluminescent matrix screen contains a vacuum shell 1 with an insulating base 2, on which are rows of anode electrodes 3, made in the form of parallel strips coated with a phosphor 4. Inside the vacuum shell 1 are located control electrodes-cathodes-emitters 7 orthogonal to the anode electrodes 3, forming at the intersection light-emitting segments 9. Emitter cathodes are made by applying carbon nanotubes 8 to control electrodes, forming (receiving) a new structural element: control electrodes-cathodes-emitters.

The operation of the cathodoluminescent matrix screen is as follows.

The screen is controlled by sequentially supplying in a pulsed mode a positive voltage to the corresponding anode electrodes 3 relative to the control electrode-cathode-emitter 7 with a duty cycle Q equal to the number of rows of the cathodoluminescent matrix screen (line: control electrode-cathode-emitter). In the new cathodoluminescent matrix screen, in which the cathode-emitters are made by applying carbon nanotubes 8 to the control electrodes, forming control electrodes-cathodes-emitters 7, the electrons are pulled out of the control electrode-cathode-emitter 7 and are scattered evenly over the area of the information field - these are rows of deposited on the insulating base 2 of the anode electrodes 3 coated with phosphor 4 (see figures 1 and 2). The control of the light-emitting segment 9 (see figure 2) is performed due to the formation of the cathode of the emitter by applying carbon nanotubes 8 to the control electrodes, forming the control electrodes-cathodes-emitters 7. The phosphor 4 begins to glow under the influence of electronic bombardment. The anode electrodes 3, on which there is no accelerating potential, are not exposed to the electron beam, and the phosphors 4 remain in an unexcited state, i.e. all other screen elements do not light up. Thus, the light emitting segments 9 located on the unselected anode electrodes are at zero potential relative to the control electrode-cathode-emitter 8, and the electron flux to the radiating segments 9 located at the intersection of the selected anode electrode 3 and the unselected control electrode-cathode-emitter 7 , locked negative voltage applied to the unselected control electrodes-cathodes-emitters 7.

By applying voltage to the selected anode electrodes 3 and control electrodes-cathodes-emitters 7 of the cathodoluminescent matrix screen, the desired image is obtained on the screen.

This invention allows to obtain cathodoluminescent matrix screens with both black and white, and color clear image, which is especially important for systems with a large working area - the information area and high information density.

EXAMPLE.

According to this technical solution, a multi-color cathodoluminescent screen was made, in which the emitter cathodes were made by applying carbon nanotubes to the control electrodes, i.e. forming control electrodes-cathodes-emitters 7.

Based on the P-626 (128 × 128) device, two devices were manufactured:

A) with anode electrodes, control electrodes and straight filament cathodes (base sample);

B) with anode electrodes and control electrodes-cathodes-emitters (the claimed technical solution).

The tests showed:

In the baseline model: A) total power P _hsumm screen consumption is 10 W / dm ^2, it consists of the power consumption of the anode electrode _upa P ≅ 1-1,5 W / dm ² (in total _exercise P - power consumption was 5 W / dm ² ) and high consumed power of incandescent filament cathodes P _n = 5 W / dm ² .

According to the claimed technical solution: B) the incandescent power of the emitter cathodes is 0, the power of the control electrodes-cathodes-emitters is 0, the consumed power of the anode electrodes remains P _a ≅ 1-1.5 W / dm ² .

Thus, in the implementation of the claimed invention, the total power consumed by the cathodoluminescent matrix screen is reduced by 9-10 times.

Tests have shown that the present invention allows to reduce the technological process in the manufacture of one device, as it excludes:

a) the manufacturing process of direct-heating cathodes and, accordingly, the cost of materials on them;

b) cathode holders and, accordingly, the cost of materials for them;

c) installation work on the assembly of a fairly complex system of straight filament cathodes and their holders.

So, installation work for the manufacture and fastening of the cathodes and their holders in the new claimed technical solution is excluded.

When the device is operating, an electric field that draws electrons from the control electrodes-cathodes-emitters provides a more uniform luminescence of the phosphor of the anode electrodes in comparison with the presence of a separate direct-filament cathode system with a large arrangement pitch t≅ 2.5-3 mm than that of the control electrodes, which the spacing t _cypp is 0.3-0.4 mm.

The ratios E, U ' _a-soup-em , X _a-soup-em indicated in the claims are determined experimentally taking into account the known laws adopted in the design of electronic devices.

Thus, the use of the described design provides, in comparison with the known designs of cathodoluminescent matrix screens, an increase in the quality of the displayed information by increasing the uniformity of the glow of the phosphors of the anode electrodes and reducing the power consumed by the cathodoluminescent matrix screen by eliminating the cathodes and more fully using the emission capabilities of the control electrodes-cathode-emitters.

Claims (2)

1. A cathodoluminescent matrix screen containing a vacuum shell with an insulated base, rows of anode electrodes deposited on an insulating base in the form of parallel strips coated with a phosphor of at least one color and connected by current paths to external leads through contact pads, cathodes, control electrodes, orthogonal to the anode electrodes and forming light emitting segments at the intersection, characterized in that the emitter cathodes are made by applying carbon nanotubes to the control electrodes rows, with the electron beam emittirovaniya when the at least one control electrode of a plurality of control electrodes at the moment when the respective anode electrodes. 2. The cathodoluminescent matrix screen according to claim 1, characterized in that the distance between the planes of the systems of anode electrodes and control electrodes-cathodes-emitters and the potential difference between the included anode electrodes and the control electrodes-cathodes-emitters are related by the ratio:

at E ~ from 1 to 20 V / μm, where E is the field strength of the control electrode-cathode-emitter, U ' _a-soup-em - the installed potential difference between the included anode electrodes and the selected selected control electrode-cathode-emitter, X _a-soup-em - the distance (μm) between the planes of the anode electrodes and the control electrodes-cathodes-emitters, in this case, for disconnected unselected control electrodes-cathodes-emitters, the potential difference U '' _a-soup-em should be in the range from 0 to ± 0.75 U ' _a-soup-em B.

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