RU2170989C2 - Array-type cathodic luminescent screen - Google Patents

Abstract

FIELD: electronic engineering; wide flat screens for television sets and vacuum luminescent displays. SUBSTANCE: screen has vacuum shell; set of directly heated cathodes; rows of phosphor-coated anode strips deposited on insulating base and connected by means of current-carrying tracks to external leads through contact pads; modulator electrodes which are orthogonal to anode strips form light-emitting segments at intersecting point; in addition, it has at least one supporting member placed between sets of anode and modulator electrodes; supporting member is mounted perpendicular to modulator electrodes and secured to insulating base by means of holders. Supporting member may be made in the form of wire produced, for example, from tungsten or its alloys and coated with insulating material or in the form of glass strip (glazing bead) whose height does not exceed distance between anode and modulator electrodes. Screen is distinguished by great number of frame- type or frameless light-emitting elements. EFFECT: enhanced reliability of screen. 3 cl, 4 dwg

Description

 The invention relates to the field of electronic technology and can be used in the manufacture of flat cathodoluminescent screens with a large number of light emitting elements (SEE), as applied to the creation of flat cathodoluminescent television screens, computer monitors, as well as for vacuum fluorescent indicators.

 Vacuum luminescent indicators are known, containing a vacuum cylinder, in which a circuit board is placed with anode electrodes located on it, which are coated with a phosphor, as well as a cathode, grids and external leads connected to the corresponding indicator electrodes (see V. Lisitsyn, Indication Elements. M .: Energy, 1978, p. 60; UK patent N 2009492, CL H 01 J 31/12, publ. 1979).

 The disadvantages of these devices is the presence of a complex system of control electrodes, made in the form of a stretched large number of grid strips, which complicates their manufacture using a volumetric vacuum cylinder and requires a large number of mounting connections.

Known luminescent display with made on the edges in contact with the luminescent segments of the grid electrodes and the method of its manufacture (see US patent and 5643034, MKI ⁶ : H 01 J 9/02, publ. 01.07.97,), containing a substrate on which are made several anodes. Luminescent layers are created on the corresponding anodes, above which the cathodes are located. On the substrate, ribs of electrically conductive material are formed surrounding at least a portion of the perimeter of each anode. The upper edge of the ribs is located at a higher height above the substrate than the upper surface of the luminescent layers. Mesh electrodes were created on the corresponding edges to control the activation of the luminescent layers. In the manufacture of a display, a system of ribs is formed on the substrate, for which several layers of insulating paste, which together form ribs, are successively applied by means of network printing. In this case, the anodes are in contact with the ribs. Further, also using the method of screening using luminescent paste, luminescent layers are applied in contact with the side surfaces of the ribs. On the upper end surfaces of the ribs by applying a conductive paste by a method of meshography perform mesh electrodes.

 The high complexity and laboriousness of the manufacture of the board inherent in this device and the process.

 One of the most critical technological operations in the manufacture of triode flat, wide-format cathodoluminescent screens is the manufacture, installation and adjustment of a control system (grid) made of a system of strips oriented along columns of light-emitting elements on the anode plate. The domestic industry and a number of leading foreign companies control electrode system is made of thin sheet material by photolithography with subsequent installation on the anode board.

 The quality of the above operation is one of the main for the manufacture of a suitable device. In the ideal case, this is an exact combination of the strips of the control electrodes with respect to the columns of FIE on the anode board, while the distances of the strips of the control electrodes to the anode board should be the same throughout the working (information) area of the screen, for the case of 7 "VFD (640 RG-B 480 ) this distance is ~ 0.8 mm.

The closest analogue in technical essence to the proposed solution - the prototype - is a multi-color cathodoluminescent screen matrix type described in the patent of the Russian Federation, application and 98113732/09 with priority from 07/21/98, MKI ⁶ : H 01 J 31/12, 31 / 20; decision on the grant of a patent dated February 4, 1999, containing a vacuum shell, a system of direct filament cathodes, rows of anode strips deposited on an insulating base, coated with a phosphor and connected to current-carrying paths with external terminals through contact pads, modulator electrodes orthogonal to the anode strips and forming at the crosshairs light-emitting segments, anode strips are arranged in alternating colors: red - green - blue (RGB), and the zones of the location of the set of external contact pads of the same color of the anode strips performed separately for each color, and the number of zones at least corresponds to the number of colors on the screen, while the length of the zone (l) is determined by the number of pads (n) corresponding to the number of lines of a given color, and the step (t) of their location and satisfies condition
l> n • t.

 In the manufacture of the screen, all 259 modulator electrodes (strips of the grid unit) should ideally be in the same plane and at the same distance from the anode board.

 Unfortunately, in real devices it is difficult to achieve perfect geometry of the stripes of the grid assembly relative to the anode board, and deviations from the ideal case take place in the manufactured devices.

 Deviations of the strips of modulator electrodes from the plane are caused by a number of subjective and instrumental errors, while it is practically difficult to ensure the identical tension force of all 259 strips of the grid unit.

In addition, the design of the grid unit in certain electrical modes is prone to the occurrence of adverse events, for example:
- the occurrence of electromechanical resonance of individual bands of the grid unit;
- electrostatic attraction of the strips of the grid unit to the anode plate or to the cathode filaments, resulting in the formation of short circuits and breaks.

 Thus, the disadvantage of this design of the multi-color cathodoluminescent screen of the matrix type is the lack of reliability of the device due to the complex design of the grid unit - modulator electrodes.

 The invention is as follows. The problem to which the invention is directed, is to increase the reliability of the screen.

 The specified technical result in the implementation of the invention is achieved by the fact that in the well-known cathodoluminescent screen of the matrix type, including a vacuum shell, a system of direct filament cathodes, rows of anode electrodes deposited on an insulating base, made in the form of strips coated with a phosphor (both single-color and multi-color, for example, with alternating colors: red - green - blue (RGB)) and connected by current-carrying tracks with external leads through pads, modulator electrodes, orthogonal ano nym electrodes and forming the light-emitting segments further comprises at least one support element disposed between the anode and modulatory systems of electrodes, wherein the support member is perpendicular to the electrode system modulator and is fixed to the insulating substrate by holders.

 In addition, the support element is made in the form of a wire, for example, of tungsten or its compounds and is coated with insulating material.

 The supporting element can be made in the form of a glass plate - a staff, while the height of the glass plate does not exceed the distance between the anode and modulator electrodes.

 The invention is illustrated by graphic materials, examples of specific performance and description.

 In FIG. 1 shows a multi-color matrix-type cathodoluminescent screen manufactured according to the proposed technical solution with a supporting element in the form of a wire.

 In FIG. 2 (a, b) schematically shows the design of a multi-color screen with a supporting element in the form of a wire: a) a general view, when the external leads are on the left, b) in section.

 In FIG. Figure 3 shows the design of a multi-color cathodoluminescent screen of a matrix type with a supporting element in the form of a glass plate - staff: general view when the external leads are in front.

 In FIG. 4 (a, b) shows the design of the cathodoluminescent screen with a support element made of a glass plate - head: a) a general view, when the external leads are on the left, b) a front view.

In the drawings, the following notation:
1 - vacuum shell
2 - insulating base,
3 - modulator electrodes made in the form of strips (in the drawing, the modulator electrodes are depicted in the form of frames, for simplicity, the grids are omitted),
4 - straight cathodes,
5 - anode electrodes made in the form of strips,
6 - anode electrodes coated with a red phosphor,
7 - anode electrodes coated with a green phosphor.

8 - anode strips coated with a blue phosphor;
9 - supporting element;
10 - holder of the supporting element 9;
11 - current-carrying tracks;
12 - external contact pad of the anode strips;
13 - external findings.

 In FIG. 1 shows an image of a cathodoluminescent screen with an insulating base 2 containing light-emitting anode strips 5 (6, 7, 8), modulator electrodes 3 made in the form of strips-frames (rods) orthogonal to the anode strips 5 and forming light emitting segments in the crosshair. An insulating base 2 with deposited anode strips 5 with alternating colors, for example, red - 6, green - 7, blue - 8 and direct-heating cathodes 4 is placed in a vacuum shell 1. The support element 9 is located between the systems of anode and modulator electrodes, while the support element 9 is perpendicular to the modulator electrodes 3 (see FIGS. 2 and 4) and is fixed on an insulating base 2 using the holders 10. There can be two or three, at least one, support elements 9 in the cathodoluminescent screen design. One of the possible options for attaching a support element from a glass plate - a stand - is carried out by installing a glass plate on a strip of a previously applied dielectric compound on an insulating base with subsequent annealing. The support element was introduced into the design of the prototype matrix multicolor cathodoluminescent screen type (see Fig. 1-4). However, the support element was equally tested in single-color screens.

 The operation of the cathodoluminescent screen of the matrix type is as follows.

 The screen is controlled by applying positive voltages to the corresponding modulator electrodes and anode strips.

 Non-working electrodes are supplied with a blocking voltage.

 The electrons emitted from cathode 4 are scattered evenly over the area of the information zone (rows of anode strips coated on the insulating base coated with a phosphor with alternating colors in the information zone: red - green - blue (RGB)) using modulator electrodes 3, onto which positive potential has been applied, and anode strips (anode electrodes) 3 coated with a phosphor 6, 7, 8 with different glow colors are bombarded in the information zone, phosphors begin to glow under the influence of electronic bombardment. Anode strips (6, 7, 8), on which there is no accelerating potential, are not affected by the electron beam, and the phosphors remain in an unexcited state.

 In this technical solution, the task is achieved by introducing the support element 9 into the screen structure, while the support element is located between the systems of anode and modulator electrodes 3, mounted on an insulating base 2 using holders 10.

According to this technical solution, a multi-color matrix-type cathodoluminescent screen was made under the name 7 "VFD (640x480) RGB. The support element was made in the form of a wire, for example, of tungsten and coated with insulating material, see figure 1; 2a, b. It was also the supporting element is made of a glass plate - a staff (see Fig. 3; 4a, b), while the height of the glass plate (h) does not exceed the distance between the anode and modulator electrodes (X _AM ), and the thickness of the glass plate (T) does not exceed thickness of modulator electrodes (t), i.e., are performed for Slovenia
h ≅ X _AM ;
T ≅ t.

Tests have shown that the present invention eliminates undesirable phenomena that occur in the screen, namely:
- the occurrence of electromechanical resonance of the bands of modulator electrodes;
- sagging, bending or deformation of the bands of modulator electrodes.

In addition, the present invention will allow:
- improve the optimization of the electronic control system relative to the anode plate (insulating base with anode strips) and cathodes;
- increase the brightness due to the possibility of increasing the voltage to the modulator electrode, while increasing the power at the modulator electrode will not lead to sagging of the modulator electrode due to the presence of the reference element.

Claims (3)

 1. The cathodoluminescent screen of the matrix type, including a vacuum shell, a system of direct filament cathodes, rows of anode electrodes deposited on an insulating base, made in the form of strips coated with a phosphor and connected to current-carrying tracks with external leads through contact pads, modulator electrodes orthogonal to the anode electrodes and forming light segments, characterized in that it further comprises at least one support element located between the systems of anode and modulator ektrodov, wherein the support member is perpendicular to the electrode system modulator and is fixed to the insulating substrate by holders.  2. The cathodoluminescent screen of the matrix type according to claim 1, characterized in that the support element is made in the form of a wire, for example, of tungsten or its compounds and is coated with an insulating material.  3. The cathodoluminescent screen of the matrix type according to claim 1, characterized in that the support element is made in the form of a glass plate - head, while the height of the glass plate does not exceed the distance between the anodes and modulator electrodes.

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