UA63295A - Flexible matrix woven electroluminescent screen - Google Patents

Abstract

The proposed flexible matrix woven electroluminescent screen is made as gauze containing parallel vertical fibers of the first type and parallel horizontal fibers of the second type. The fibers of the first type are arranged perpendicular to the fibers of the second type and touch each other at the crossing points, forming electric contact connections at these points. The fibers are isolated from each other by technological treads providing the woven structure of the screen. The screen is divided into sections, so that each section contains all the screen vertical fibers and the number of the horizontal fibers equal to the number of all the horizontal fibers divided by the number of the sections. The screen is divided into sections by the technological treads.

Description

Description of the invention

The proposed invention relates to information display devices, in particular, to 2 thin-film matrix electroluminescent screens, which are made on a flexible film base.

An electroluminescent screen is a system of electroluminescent capacitors, each of which consists of an electroluminescent layer located between two electrodes, at least one of which is transparent to emit radiation, as well as (in the case of a thin-film electroluminescent layer) current-limiting dielectric layers on both sides of the electroluminescent layer .

The matrix electroluminescent screen is a system of mutually perpendicular rasters of electrodes, columns and rows, each intersection of which forms the above-described electroluminescent capacitor (single pixel). During the display of information on such a screen, the exciting voltage is applied to the corresponding pixel using row and column electrodes. Provided that the voltage on the covers of the electroluminescent capacitor-pixel will exceed the threshold value of the voltage, which corresponds to the field strength in the thin-film electroluminophore 2710 5V/cm, and in the thick-film electroluminophore 109V/cm, a glow occurs in the electroluminescent layer, which exits through the transparent electrode.

In the case of a matrix screen, the columnar electrodes are informational, that is, they are responsible for sampling in each row of pixels, light and dark, and the polling of the matrix screen is sequential, that is, information is first transmitted to the pixels of the first row, then the second, and so on to the last, which corresponds to the display of one frame of information. Based on the requirement to change frames with a frequency of 50Hz, i.e. 1/5Osec, it can be determined that with a number of lines of 1600, the time for polling one line is 20μsec, which is less than the optimal frequency of 5μsec. At the same time, by increasing the polling frequency (frame change frequency) with the length of the Exciting pulse, at least 40-5B0μsec, it is possible to significantly (practically proportional to the frame change frequency) increase the brightness of the matrix electroluminescent screen.

Changes in the material of the luminescent layer, the thickness and composition of the structure of the electroluminescent capacitor can lead to a change in the color of the glow, operating (threshold) voltage, brightness of radiation, contrast, but the dependence of brightness on the frame rate is preserved. i am

Widely known thin-film electroluminescent matrix screens created on solid substrates made of glass or ceramics manufactured by 5Ppagr (Japan), Riapag (USA), Lohya (Finland), MES (Japan), GRige F (Canada). Their structure is made by the method of vacuum or chemical deposition of layers, and the grids of Ge electrodes are formed by the photolithography method. These screens are distinguished by a sufficiently high brightness of radiation, but have limitations in both linear dimensions and the number of columns and rows. This is related to the technological and structural features of these screens. (Se)

There are known screens that are made on the basis of flexible polymer films, in particular light-emitting polymers (SVP-GER), for example, described in Yuba patent Mo5.399.502. The material of the screen contains a semiconductor

SVP - a layer laminated with two conductive layers. The layers are formed by spraying or sputtering and “set the fundamental limits on the screen size. The raster pattern of the control electrodes, like that 470 described above, is formed from two conductive layers using photolithography, which also imposes restrictions on the size of the device. Size limitations are mainly overcome in flexible screens made of two sets of fibers that are organized into two-dimensional grids, as shown, for example, in BA patents Mo5.962.967 and Mob.072.619. Each fiber contains a longitudinal conductor. Fibers of at least one type are coated with a reflective or other active electrostatic substance. A display element (pixel) is formed at each intersection (22) of a fiber of one row with a fiber of a second row. Two-dimensional gratings can be formed by superimposing fibers of one row (raster) on a second row , but in such a structure the preference is given to bonding (weaving) two sets of fibers. The fibers can have a round or flat cross-section. The fiber manufacturing process does not impose restrictions on length and width, and using traditional weaving methods, flexible screens can be obtained from 50 large linear dimensions. When making woven screens, there is no need to use various technologies (photos tography, lithography), since the structure of the matrix is formed by weaving or overlapping fibers, which makes it possible to obtain a sufficiently uniform geometry of the screen. At the same time, woven screens are even lighter and more flexible. But the limitation of the number of lines is also inherent in this technical solution.

A woven screen made of a set of flat fibers or intersecting strips is described in UMO patent 99119858. One set can consist entirely of display strips (a ready-made strip structure without any "electrode") while the other set consists of conductive strips, or both sets can consist of a finished structure and a conductive strip. The display strip in this case has a rear conductive layer, an intermediate luminescent layer and a front conductive layer. The display elements are formed at the junctions where the conductive strip 60 contacts the back conductive layer of the display strip.

A woven screen is known (UUO patent 99/19858), in which additional structural threads alternating with row and column display strips are used to separate the display information strips in such a structure. They do not carry information, but only appear as structural elements for separating information display strips. In addition, according to this technical solution, one of the display strips contains in itself a completely ready-made electroluminescent structure with a back electrode that is not solid, the size corresponding to the width of the second metal display strip (pixel width). But at the same time, the second display strip can be an ordinary wire.

All woven and non-woven screens mentioned above have thread electrodes and represent a group of powder electroluminescent devices (excluding screens on a solid glass or ceramic substrate).

This type of (woven, woven) indicator is very easy to manufacture, but has relatively low brightness, contrast, service life and steepness of the voltage-brightness characteristics. This makes it impossible to create, based on this type of indicators, full-size matrix television screens with the required brightness and the required number of gradations of brightness in real outdoor lighting conditions.

Thin-film matrix electroluminescent screens have higher performance characteristics, but they also have brightness limitations associated with the number of information lines, the duration of the exciting pulse, and the frequency of changing the frame image.

The invention is based on the task of creating a flexible matrix braided electroluminescent screen, in which, thanks to the possibility of dividing this screen into separate controllable fragments, an increase in the scanning frequency (or frame change frequency) of each fragment or the entire screen is ensured, and at the expense of 7/5 of this, the brightness of the image significantly increases .

The task is solved by the fact that in a flexible matrix braided electroluminescent screen, which contains a system of parallel columnar information fibers and a system of parallel row information fibers, and the first and second systems are mutually perpendicular and touching have ohmic contact and mechanical connection with each other , all information 2o Fibers are separated from each other by technological threads that do not carry information and participate in the weaving of the matrix screen, according to the invention, the screen along the row information fibers is divided into fragments in such a way that the number of columnar information fibers is equal to the number of columns of the entire matrix screen, and the number of row information fibers is equal to the number of rows of the entire matrix screen, divided into the number of fragments, while the separation of fragments occurs with the help of a dividing system of technological threads, which are located along and between the row fibers of the dry days of fragments; the end of each information column fiber with the help of a technological thread is brought to the back of the screen, where it is combined with an individual circuit board for each fragment, which is the basis for the control scheme of this fragment; control of the screen is carried out with the help of a processor located on the back of the screen and connected to all circuit boards. The number of fragments involved in the operation of the screen can be equal to two or more.

In some cases, circuit boards on which various types of control schemes are placed, both for a separate fragment of the screen and for the entire screen as a whole, can be multi-layered. with

Mechanical fastening of circuit boards and information and power cables is made on technological threads on the back side of the screen. at

Figure 1 shows a general view of a braided matrix electroluminescent screen, which consists of columnar information fibers (1), row information fibers (2) and technological threads (3).

This screen consists of two fragments (A) and (B) of the screen, and the separation zone of the columnar electrodes (1) of each fragment is the region (C) along one of the technological threads (4), which separates the lowermost row fiber (2) fragment (A) and the uppermost row fiber (2"). "

For a better understanding of the essence of the technical solution and illustrative examples of the implementation of its main provisions, all of them will be described with the help of an example with reference to the accompanying drawings, in which:

Fig. 2 schematically shows options for combining fragmentary screens (A, B) into one integral one according to using technological threads (3) on the example of one of the information columnar fibers (1, 1). Row information fibers are marked as (2, 2), and weaving options are shown in Fig. 2a, 26 and 2c. At the same time, as we can see, the number of technological threads (3) separating the screen fragments can be different.

Figure 3 shows the structure of column (a) and row (c) information fibers of electroluminescent matrix powder (I) and thin film (II) screens. Figure 4 shows options for laying information fibers in the case of powder (I) and thin-film (II) electroluminescent screens.

Let's consider in more detail the operation of the proposed flexible matrix braided electroluminescent and screen design. The number of screen fragments depends on its information capacity and the necessary brightness of the displayed information. Since the usual afterglow (the glow of the phosphor after the end of the excitation pulse) is equal to about msec, that is, the best frequency of addressing the line (according to the sequential scan of dv during polling) is equal to 1000Hz. If the duration of the excitation pulse is 30-5 Ohmsec (line polling time), the number of lines in the fragment should be from 32 to 16. At the same time, the effective brightness of the screen compared to

P with a standard frame rate of 50 Hz can increase 20 times, which is necessary for both powder matrix screens and thin film screens in the KOV mode.

Fig. 1 shows the general appearance of a braided matrix electroluminescent screen, which consists of column (1) and row (2) information fibers. A set of columnar (1) information fibers are parallel to each other and cross at right angles to a set of row (2) information fibers, which are also parallel to each other. Between each linear (2) or columnar (1) information fibers there are technological threads (3), which do not participate in the transmission and display of information, but at the same time participate in weaving the screen. With their help, the distribution of 65 different fragments (A, B) of the screen and their mechanical connection in the area (C) takes place. Each intersection (each overlap) of column and row fibers creates a single pixel.

Fig. 2 schematically shows a version of the distribution of columnar (1, 1) information fibers of adjacent fragments (A, B) of the screen. As can be seen from the figure, the columnar (1, 1) fibers reaching the distribution zone (C) are bent with the help of technological threads (3 C) and exit to the back surface of the screen. At the same time, technological threads connect fragments A, B into a continuous screen.

Fig. 2 a, b, c show variants of these combinations using different numbers of technological threads (C to C).

In the creation of this type of screens, information fibers can be used, which are made on the basis of thin film and powder technologies and differ in their structures.

Fig. 3 shows the structures of columnar (a) and row (c) information fibers for 7/0 electroluminescent screens based on inorganic powders (I) and created by thin-film technology (I).

The structure of the ordinary (2) information fiber is the same for both cases (I, II), it consists of a carrier tape-substrate (5) of organic origin, for example, polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, cyanoethyl cellulose, etc., 10-100 microns thick , reinforced with wire electrodes 7/5 (6), a layer of metal (wire electrodes) (9) is applied to the surface of the film, which has an ohmic contact with the electrodes (6).

The structures of columnar information fibers (1) vary depending on the manufacturing technology. Thus, in the production of powder screens, the structure of the fiber is as follows: the carrier tape-substrate made of organic material is doped with (50-90)95 powder inorganic phosphor (4) 10-50 microns thick, reinforced with wire electrodes (6) and has on the surface of the tape-substrates from the side the output of the radiation is a conductive layer (7) that has an ohmic contact with the electrodes (6). A metal layer (8) is applied to the opposite side of the backing tape.

Fig. ZPa shows the structure of columnar information fibers (2) in the variant of thin-film technology. It consists of a supporting transparent organic tape-substrate (5), reinforced with wire electrodes (6) and sequentially arranged following layers: a transparent conductive layer (7), which has an ohmic

Contact with electrodes (6), first double dielectric layer (10), electroluminescent layer (12), second double dielectric layer (11) and metal layer (8). "

Figure 4i shows the structure of a single pixel obtained due to the electrical and mechanical connection of mechanical layers (8,9) in the interweaving of column (1) and row (2) information fibers. During weaving, the metal layers of both types of fibers touch and an electrical and mechanical contact is formed, and the structure of single pixels will look as shown in Fig. (41Y).

But in proportion to the number of fragments of the matrix screen, the number of control elements increases, or at least the number of final cascades of control schemes. This can cause overloading of control circuits around the perimeter of the matrix screen.

According to the main clause of the proposed invention, the column electrodes (1) of each fragment me) z5 are connected to flexible loops-boards on which the final cascade of column control circuits is located, and (9 namely multi-channel microcircuits containing high-voltage switches and shift registers, and this allows to significantly (in proportion to the number of key cascades) reduce the number of information cables to each fragment.

The general processor in the variant of the fragmented screen crushes the image of the frame into fragments and transfers each fragment to the corresponding control circuits, thus displaying the complete picture by "

The entire matrix screen as a whole, while the frame repetition rate can increase from 50Hz to 1000Hz. s s The rest of the structural elements (loops-boards, their connection and fixation on technological threads) are not . is illustrated with pictures, since these solutions are clear even without an illustration. and?

Claims (4)

The formula of the invention Me, - - - ! - ! 1. A flexible matrix braided electroluminescent screen containing a system of parallel to each other column information fibers and a system of parallel to each other row information fibers, with the first and second systems mutually perpendicular and, touching, have ohmic contact and mechanical connection with each other ; all information fibers are separated from each other by technological threads that do not carry information, but participate in the weaving of a matrix screen, which differs in that the screen along the line information fibers is divided into fragments in such a way that the number of column information fibers is equal to the number of columns of the entire matrix screen, and the number of line information fibers is equal to the number of lines of the entire matrix screen divided by the number of fragments; at the same time, the distribution of fragments occurs with the help of a distribution system of technological threads located along and between the row fibers of neighboring fragments; the end of each informational columnar fiber P" with the help of a technological thread is brought to the back of the screen, where it is connected to the circuit board isolated for each fragment, which represents the control scheme of this fragment; control of the screen is carried out with the help of a processor located on the back of the screen and connected to all the circuit boards. 2. The screen according to claim 1, which differs in that the number of fragments can be equal to two or more. Q. The screen according to claim 1, which is characterized by the fact that the circuit boards can be multi-layered to accommodate various types of control schemes for both screen fragments and the screen as a whole. 4. The screen according to claim 1, which differs in that the mechanical attachment of circuit boards and information-power 65 cables is performed on technological threads on the back side of the screen.