RU2541160C2 - Cathodoluminescent display and control method thereof - Google Patents

Abstract

FIELD: physics, computer engineering.

SUBSTANCE: invention relates to displays and can be used to design cathodoluminescent displays and a method for controlling said displays. A cathodoluminescent display 1 comprises a first glass substrate 2 and a second glass substrate 3, and a cavity 4 between said substrates is filled with a low-pressure inert gas. On the inner side 5 of the first substrate 2 there are pixels 6 which are luminophore-coated 7 conducting pixel areas 8 made of light-transmitting material. There is a conducting frame 9 around each pixel 6. On the inner side 10 of the second substrate 3 there are conductors of a first group 11 and conductors of a second group 12, wherein on the conductors of the first group 11 there are cold cathodes 13, and on the conductors of the second group 12 there is a porous film 14 made of material having a secondary electron emission property.

EFFECT: longer service life of the cathodoluminescent display.

8 cl, 5 dwg

Description

The claimed group of inventions relates to displays and can be used to create cathodoluminescent displays and how to control them.

Known flat cathodoluminescent display containing a glass substrate with many coated with phosphors pixels. The display contains cold cathodes emitting electrons. Image formation in the display is carried out by applying a positive voltage to the selected pixels. When electrons are bombarded with phosphors of selected pixels, light is emitted (see US patent No. 8120550, IPC G09G 3/20, publ. 02.21.2012).

The disadvantage of this display and its control method is that cold cathodes are used in the regime of constant emission of electrons with a high current density, which limits its service life.

The closest analogue prototype is a cathodoluminescent display containing the first and second glass substrates, and the cavity between them is filled with an inert low-pressure gas. On the inner side of the first glass substrate are pixels, which are conductive pixel pads coated with a phosphor. Around each pixel is a conductive frame on which cold cathodes on carbon nanotubes are located. Conductors are placed on the inside of the second glass substrate. When a positive voltage is applied to these conductors and to the selected pixels, and to the negative voltage frame, a non-independent Townsend gas discharge arises and is constantly maintained due to the constant emission of electrons from the cold cathodes. Electrons from a gas discharge bombard the phosphors of the selected pixels and they glow (see US patent No. 8223101, IPC G09G 3/36, published on July 17, 2012).

The disadvantage of the design and control method of this cathodoluminescent display is its low life. This is due to the fact that in order to maintain a non-self-sustained gas discharge, cold cathodes operate in the mode of constant electron emission.

The objective of this solution is to develop such a cathodoluminescent display design that would ensure its operation in the regime of unstable electron emission from cold cathodes and thereby increase the life of the cathodoluminescent display.

The specified technical result in the implementation of the invention is achieved by the fact that in the known cathodoluminescent display and its control method, the display contains cold cathodes, first and second glass substrates, a cavity between them filled with an inert low-pressure gas, pixels are located on the inner side of the first glass substrate, which are pixels phosphor-coated conductive pixel pads, a conductive frame is placed around each pixel, on the inside of the second glass substrate is placed Guides us. The conductors located on the second substrate are divided into at least two groups, with cold cathodes placed on the conductors of the first group, and a porous film of material having the property of secondary electron emission is deposited on the conductors of the second group. Groups of conductors have external terminals for connection to voltage sources. The pixel pads on the first glass substrate are made of light transmitting material. Cold cathodes are made according to one of the well-known technologies: emitters based on carbon nanostructures, planar-face emitters, tip emitters. The display control is carried out in the following way. The first positive voltage is applied to the selected pixels through the drivers, and the second positive voltage is applied to the conductive frame. The display time of the current frame is divided into two stages. During the first stage, a negative voltage is applied to the conductors of the first group, and zero voltage is applied to the conductors of the second group, which initiates a non-self-contained gas discharge between the first and second substrates. During the second stage, the conductors of the first group are disconnected from the negative voltage, and the second positive voltage of the source is set sufficient to maintain an independent discharge between the first and second substrates. At the end of the display time of the current frame, the conductors of the second group are disconnected from zero voltage and, thereby, stop the gas discharge.

An increase in the service life is ensured by reducing the time of electron emission from cold cathodes, since electron emission occurs only during the first stage of the current frame display and does not exceed 5 percent of the frame display time. An increase in image quality occurs as a result of an increase in image contrast and the possibility of forming a gray scale of brightness using a pulse-width method. Contrast is enhanced by viewing the image through transparent pixel pads on the outside of the first substrate. Disconnecting the conductors of the second group from zero voltage leads to the termination of the gas discharge and the extinction of all pixels, which allows the use of a pulse-width method of forming a gray scale.

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

Figure 1 presents a schematic device of a cathodoluminescent display.

Figure 2 shows the inner side of the first glass substrate.

Figure 3 shows the inner side of the second glass substrate.

Figure 4 shows a block diagram of the inclusion of the proposed cathodoluminescent display.

5 is a voltage diagram illustrating a method for controlling a cathodoluminescent display.

The following notation is introduced in the drawings:

1 - flat cathodoluminescent display;

2 - the first glass substrate;

3 - the second glass substrate;

4 - a cavity between the first and second glass substrates;

5 - the inner side of the first glass substrate;

6 - pixels;

7 - phosphor;

8 - pixel pads;

9 - conductive frame;

10 - the inner side of the second glass substrate;

11 - conductors of the first group;

12 - conductors of the second group;

13 - cold cathodes;

14 - a porous film;

15 - driver;

16 - pixel outputs;

17 - the first source of positive voltage;

18 - output frame;

19 is a second source of positive voltage;

20 - display time of the current frame;

21 - the first stage of displaying the current frame;

22 - the second stage of displaying the current frame;

23 - the first key;

24 - the second key;

25 - output conductors of the first group;

26 - source of negative voltage;

27 - output conductors of the second group;

28 - a common point of voltage sources;

29 is the outer side of the first glass substrate.

In accordance with the present invention, the cathodoluminescent display 1 comprises a first glass substrate 2 and a second glass substrate 3, the cavity 4 between them is filled with an inert low-pressure gas. On the inner side 5 of the first substrate 2, pixels 6 are arranged, which are conductive pixel pads 8 made of a light transmitting material coated with a phosphor 7. Around each pixel 6 is a conductive frame 9. On the inner side 10 of the second substrate 3, the conductors of the first group 11 and the conductors of the second group 12 are placed, and cold cathodes 13 are placed on the conductors of the first group 11, and a porous film 14 of material is applied to the conductors of the second group 12 having the property of secondary electron emission.

Management of the cathodoluminescent display 1 according to the claimed method is as follows (see figure 4, 5). The driver 15 through the pixel pins 16 connects the voltage + Vp to the first source of positive voltage 17, the pixels 6 in accordance with the displayed information should glow. The output 18 of frame 9 is supplied with voltage + Vfr from the second source of positive voltage 19. The display time of the current frame 20 is divided into two stages 21 and 22. During the first stage 21, the first key 23 and the second key 24 are closed. The conductors of the first group 11 through the output 25 will be connected to a source of negative voltage 26 voltage -Vc. The conductors of the second group 12 through the terminal 27 are connected to the common point 28 of the voltage sources 17, 19, 26. The electrons emitted by the cold cathodes 13, moving to the frame 9, the selected pixels 6 and to the conductors of the second group 12, are called between the first substrate 2 and the second substrate 3 non-self-contained gas discharge. Electrons from the gas discharge cause the phosphor 7 to glow only the selected pixels 6, the remaining pixels 6 do not glow. Thus, the display of information begins - "Display". During the second step 22 of displaying the current frame, the first key 23 is opened - "OFF", the emission of electrons from the cold cathodes 13 is stopped. But since there is an electric field between the frame 9 on the first substrate 2 and the conductors of the second group 12 on the second substrate 3, an independent gas discharge will be maintained between the substrates 2 and 3, and the information display will continue. At the end of the second stage 22, the second key 24 is opened, the gas discharge stops, and all the pixels 6 are not lit - "no light". The described control steps are then repeated for the next image frames. The voltage + Vp of the first source of positive voltage 17 and the voltage + Vfr of the second source of positive voltage 19 depending on the inert gas pressure in the display 1 can match. The image is viewed from the outside 29 of the first glass plate 2. Similarly, the information of the following frames is displayed.

The separation of the conductors on the second glass substrate into at least two groups and the placement of cold cathodes on the conductors of the first group and on the conductors of the second group of a porous film of material having the property of secondary electron emission allows the initiation of a non-self-triggering electron emission from cold cathodes by displaying an image frame gas discharge between the first and second substrates, and then maintain an independent gas discharge. The time of electron emission from cold cathodes is no more than 5 percent of the display time. Thus, the claimed technical result is achieved - increasing the service life of the cathodoluminescent display by reducing the time of electron emission from cold cathodes.

Another technical result - improving the quality of the displayed information is achieved by the manufacture of pixel pads from a material that transmits light. In this case, when viewing the image from the outside of the first substrate, the quality (contrast) of the displayed information increases, since the glow of the gas discharge is not visible.

In addition to the above results, disconnecting the conductors of the second group from voltage sources, at which the gas discharge and the luminescence of the pixels ceases, allows the pulse-width method to implement a gray scale of brightness of the luminescence of pixels, which improves the quality of the displayed information.

Claims (8)

1. A cathodoluminescent display containing cold cathodes, first and second glass substrates, the cavity between which is filled with an inert low-pressure gas, pixels are located on the inner side of the first glass substrate, which are conductive pixel pads coated with a phosphor, a conducting frame with an output is placed around each pixel, conductors are arranged on the inner side of the second glass substrate, characterized in that the conductors are divided into at least two groups, moreover, on the conductors The first group contains cold cathodes, and a porous film of a material having the property of secondary electron emission is deposited on the conductors of the second group, while the groups of conductors have external leads. 2. The cathodoluminescent display according to claim 1, characterized in that the pixel pads on the first glass substrate are made of light transmitting material. 3. The cathodoluminescent display according to claim 1, characterized in that the cold cathodes are emitters on carbon nanostructures. 4. The cathodoluminescent display according to claim 1, characterized in that the cold cathodes are planar-face emitters. 5. The cathodoluminescent display according to claim 1, characterized in that the cold cathodes are tip emitters. 6. A method for controlling a cathodoluminescent display according to any one of claims 1 to 5, characterized in that the image frames are formed by applying the first positive voltage to the selected pixels through the driver, the second positive voltage is applied to the conductive frame, and each current frame is displayed in two stages, at the first stage they provide a non-self-contained gas discharge between the first and second substrates, at the second stage they provide an independent discharge between the first and second substrates. 7. The method according to claim 6, characterized in that during the first stage, negative voltage is applied to the conductors of the first group, and zero voltage is applied to the conductors of the second group, during the second stage, the conductors of the first group are disconnected from the negative voltage after the current frame is displayed the conductors of the second group are disconnected from zero voltage. 8. The method of controlling the cathodoluminescent display according to claim 6 or 7, characterized in that the values of the first and second positive voltages coincide.

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