RU2179766C2 - Matrix-type luminous cathodic screen - Google Patents

Abstract

FIELD: electronic engineering; flat screens with many light-emitting parts; luminescent television screens, and vacuum luminescent displays. SUBSTANCE: screen has evacuated envelope built up of face panel and insulating base with rows of evaporated anode electrodes in the form of parallel bars covered with phosphor of at least one color and connected by means of current-carrying tracks to external terminals through contact pads; set of filamentary cathodes; control electrodes which are orthogonal to anode electrodes and form light-emitting segments; insulating frame interconnecting through sealed joint face panel and insulating base; novelty is introduction of cathode grid curtain with duty factor 0,1±0,06 following condition being satisfied:

, where K is grid-curtain duty factor; S_cm is area occupied by cathode-grid curtain metal; S_W is cathode-grid window area; distance between set of cathodes and cathode grid as well as between cathode grid and set of control electrodes meets following inequality: 1/2X_Cg-Cl≤ X_C-Cg< X_Cg-Cl, where X_C-Cg is distance between set of cathodes and cathode grid; X_Cg-Cl is distance between cathode grid and set of control electrodes. In addition cathode grid is placed between set of control electrodes and set of cathodes; cathode grid is placed between face panel and set of cathodes. Novelties introduced provide for enhancing current take-off to anode and brightness of glow, chrome, visible uniformity of brightness in different colors, and for reducing parasitic contrast. EFFECT: enhanced economic efficiency and service life of screen. 3 cl, 2 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 well as in the manufacture of flat cathodoluminescent television screens and vacuum fluorescent indicators.

 Vacuum luminescent indicators (VLI) are known, which contain a vacuum cylinder in which a circuit board is placed with anode electrodes located on it and 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, 5-6, 1982, p. 88-89).

 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, while they are located at the same distance from the anode segments and at intervals between them, which narrows the ergonomic parameters of the indicator: overall brightness, viewing angle.

 Known cathodoluminescent indicator of the matrix type, described in the book of B. Gorfinkel. et al. "Low-voltage cathodoluminescent indicators", Moscow: "Radio and communications", 1983, pp. 33-34, Fig. 18, containing a vacuum cylinder and a flat glass plate on which anode segments with a coated phosphor layer and connecting conductors, as well as the cathode and control electrodes, which are fixed on the holders. The control electrodes are made in the form of grids located in the plane between the cathodes and anodes. The grids are isolated from each other (do not touch each other), while each grid is edged with a frame.

 A significant drawback of such VLIs is that the luminescence of the phosphor covering the anodes is effected by supplying positive voltages — tens of volts to the anodes and grids.

The closest analogue in technical essence to the proposed solution - the prototype - is a multi-color cathodoluminescent screen of the matrix type described in RF patent 2137246, publ. 09/10/99, MKI ⁶ : H 01 J 31/12; 31/20. In a multi-color cathodoluminescent matrix-type screen containing a vacuum shell, a direct-filament cathode system, rows of anode strips deposited on an insulating base, coated with a phosphor and connected to current-carrying paths with external leads through contact pads, control electrodes orthogonal to the anode strips and forming light emitting segments at the crosshairs the stripes are arranged in alternating colors: red - green - blue (RGB), and the zones of the location of the set of external contact pads are of a different color of the anode strips are made separate for each of the colors, and the number of zones at least corresponds to the number of colors of the screen, while the length of the zone (l) is determined by the number of contact pads (n) corresponding to the number of lines of the given color and the step (t) of their location and satisfies the condition: l≥ n • t.

 A limitation of this design is the relatively low specific current collection at the anode and, accordingly, the insufficient brightness of the glow.

 The invention is as follows. The problem to which the claimed invention is directed, is to expand the functionality of the cathodoluminescent matrix-type screen by increasing the current collection at the anode and the brightness of the glow, saturation, apparent equilibrium of the brightness of various colors, reducing the "spurious" contrast and at the same time increasing its economy and durability.

где К - коэффициент заполнения сеточного полотна катодной сетки;
S_ПМ - площадь занятого металлом полотна катодной сетки;
S_O - площадь окна катодной сетки,
при этом расстояния от системы прямонакальных катодов до катодной сетки и от катодной сетки до системы управляющих электродов удовлетворяют следующему неравенству:
1/2 Х_Cк-Супр ≤ Х_К-Ск ≤ Х_{Ск-Супр},
где Х_К-Ск - расстояние от системы прямонакальных катодов до катодной сетки;
Х_{Ск-Супр} - расстояние от катодной сетки до системы управляющих электродов.The specified technical result in the implementation of the invention is achieved by the fact that in the known cathodoluminescent screen of the matrix type, including a vacuum shell, consisting of a plate and an insulating base with rows of deposited anode electrodes made in the form of parallel strips coated with a phosphor of at least one color, and connected by current-carrying tracks with external terminals through contact pads, a direct-heating cathode system, control electrodes orthogonal to the anode electrodes and forming light radiating segments, a dielectric frame hermetically connecting the front plate and the insulating base, an additional cathode grid is introduced in the form of a mesh web with a fill factor K = 0.1 ± 0.06, while the condition is fulfilled:

where K is the fill factor of the grid web of the cathode grid;
S _PM - the area occupied by the metal sheet of the cathode grid;
S _O is the window area of the cathode grid,
the distances from the system of direct filament cathodes to the cathode grid and from the cathode grid to the system of control electrodes satisfy the following inequality:
1/2 X _Ck-Supr ≤ X _K-Ck ≤ X _Ck-Supr ,
where X _K-SK - the distance from the system of direct filament cathodes to the cathode grid;
X _SC-Supr - the distance from the cathode grid to the control electrode system.

 In addition, the cathode grid is located between the control electrode system and the direct filament cathode system.

 In addition, the cathode grid is located between the plate and the direct filament cathode system.

 The invention is illustrated graphic materials.

 In FIG. 1 shows a cathodoluminescent screen of a matrix type in accordance with the proposed technical solution: the cathode grid is located between the control electrode system and the filament cathode system.

 Figure 2 shows the cathodoluminescent screen of the matrix type, in which the cathode grid is located between the front plate and the direct filament cathode system.

The following notation is accepted:
1 - insulating base;
2 - plate;
3 - dielectric frame;
4 - straight cathodes;
5 - anode electrodes;
6 - phosphor;
7 - control electrodes;
8 - cathode grid;
9 - contact pads;
10 - external findings;
11 - conductive layer.

 The matrix-type cathodoluminescent screen contains a transparent vacuum shell composed of an insulating base 1 with rows of deposited anode electrodes 8 made in the form of parallel strips coated with a phosphor 6 and connected by current paths through contact pads 9 with external leads 10. The control electrodes 7 are orthogonal to the anode electrodes 5. The dielectric frame 3, made, for example, of glass posts, is located around the perimeter of the insulating base 1, hermetically connects it to the plate 2, forming a vacuum new shell. An insulating base 1 with deposited anode electrodes 5, made in the form of parallel strips, a straight filament cathode system 4, a control electrode system 7 and a cathode grid 8 is placed inside the vacuum shell. In this case, the cathode grid 8 is located between the control electrode system 7 and the direct filament cathode system 4.

 In the main electric mode, a positive potential is supplied to the control electrode 7 and the anode electrode 3 with respect to the directly heated cathode 4 heated by an electric current.

 The device operates as follows.

 Under the influence of an electric field, the electron stream emitted by the direct-flow cathode 4 penetrates through the control electrode 7 onto the anode electrode 5 and, depending on the potential distribution on the latter, bombards the phosphor 6 with a corresponding intensity distribution, causing a corresponding optically visible image. The cathode grid 8 as a whole can accordingly change the intensity distribution of the electron bombardment of the phosphor 6 with a fixed potential distribution over the control electrode 7 and the anode electrode 5, thereby expanding the functionality of the device.

 With a fixed-cost cathode (incandescent power), due to the cathode grid 8, it is possible to reduce the potentials of the control electrode 7 and the anode electrode 5, increase the efficiency along the power supply circuit of these electrodes, and at the same time reduce the energy of the ions bombarding (destroying) the direct-heating cathode 4, thereby increasing the device durability .

The cathode grid 8, made in the form of a grid web with a fill factor of 0.1 ± 0.06, allows you to form an image on the phosphor 6 at a specific location between the system of control electrodes and the system of direct cathodes, provided
1/2 X _Ck-Supr ≤X _K-Ck ≤X _Sk-Supr .

The ratios specified in the claims between the parameters (geometric dimensions) X _Sk-Supr , X _K-Supr are determined experimentally taking into account the known laws adopted in the design of electronic devices.

 The inventive device can be manufactured by the methods of mass production of cathodoluminescent screens of the matrix type.

 The performance of the claimed device is confirmed experimentally: at present, the proposed design of the cathodoluminescent screen of the matrix type is made and tested.

 This invention allows to obtain cathodoluminescent screens of the matrix type, providing reliable readout of information, a clear image, which is especially important for systems with a large working area and high information density.

Claims (3)

1. The cathodoluminescent screen of the matrix type, comprising a vacuum shell, consisting of a front plate and an insulating base with rows of deposited anode electrodes made 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 , a system of direct filament cathodes, control electrodes orthogonal to the anode electrodes and forming light emitting segments, a dielectric frame hermetically connecting the face plate and zoliruyuschuyu basis, characterized in that it additionally introduced as a cathodic mesh grid webs with a duty cycle of 0.1 ± 0.06, wherein the following condition is satisfied

where K is the fill factor of the grid web of the cathode grid;
S _pm - the area occupied by the metal sheet of the cathode grid;
S _about - the area of the window of the cathode grid,
the distances from the direct-heating cathode system to the cathode grid and from the cathode grid to the control electrode system satisfy the following inequality:
1/2 X _SC-Supr ≤X _K- SC <X _SC-Supr ,
where X _K-SK - the distance from the system of direct filament cathodes to the cathode grid;
X _SC-Supr - the distance from the cathode grid to the control electrode system.  2. The cathodoluminescent screen of the matrix type according to claim 1, characterized in that the cathode grid is located between the system of control electrodes and the system of directly heated cathodes.  3. The cathodoluminescent screen of the matrix type according to claim 1, characterized in that the cathode grid is located between the front plate and the direct filament cathode system.

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