WO1991010340A1

WO1991010340A1 - Electroluminescent flat display and process for producing it

Info

Publication number: WO1991010340A1
Application number: PCT/DE1990/000996
Authority: WO
Inventors: Gerhard Mahler; Regina MÜLLER-MACH; Gerd Otto MÜLLER
Original assignee: Koordinierungs- Und Abwicklungsstelle Für Die Institute Und Einrichtungen Der Ehemaligen Akademie Der Wissenschaften Der Ddr; HEINRICH-HERTZ-INSTITUT FüR NACHRICHTENTECHNIK BERLIN GMBH
Priority date: 1989-12-21
Filing date: 1990-12-21
Publication date: 1991-07-11
Also published as: DE3942699A1

Abstract

Coloured thin-film electroluminescent flat displays may be formed with a white light emitter layer (4) and colour filters. They are used as very small or large-format two, multi or fully coloured optical displays with a pixel raster size in the range between the micrometre and a few millimetres, especially for the very small, large and very large-format reproduction of coloured moving images, e.g. for high-definition television (HDTV). With the substrate plate (1) of the flat display as its rear surface and the reflecting electrodes (2) structured directly on the substrate plate (1) and colour filters (7) in front of transparent electrodes (8) on the front surface of the flat display, parallaxes and colour distortions are prevented and a self-adjusting structure of the transparent electrodes (8) covered by the colour filters (7) is facilitated.

Description

Electroluminescent flat display and method for producing such flat displays

The invention relates to an electroluminescent flat display and to a method for producing such flat displays.

The areas of application of flat displays are in particular where the use of cathode-ray picture tubes is not expedient or not possible, e.g. with very small or very large-format optical display means. Their pixel pitch is in the range between μm and a few mm. For small format displays, e.g. In the case of handheld or tabletop devices, there are generally no extreme demands on the color range, the intensity grading, etc. Cathode-ray color picture tubes would therefore be far too complex for such purposes. A large and large format reproduction of moving color images is, for example, in the standard of high-definition television (HDTV) and for a viewing distance that corresponds to approximately twice the picture height, with cathode ray picture tubes for weight and other reasons, in particular construction-related reasons, and therefore no longer possible and therefore only realizable with projection devices.

With a pixel grid dimension in the mm range at large viewing distances, flat displays offer the high resolution required for HDTV and are then competitive with projection devices or superior to those for home use, for example, if an otherwise comparable picture quality is achieved . The essential target parameters can in principle be met with both plasma and liquid crystal and with electroluminescent flat displays. The following points of view speak in favor of electroluminescence thin film Giving displays good prospects for use in large quantities.

The excellent structuring ability of the electroluminescent display according to the invention up to color triple or quadruple dimensions in the range of a few μm enables use for spectacle displays, e.g. for future three-dimensional or stereoscopic HDTV applications in which the left-eyed image is imprinted on the left spectacle lens display, the right-eyed image is embossed on the right spectacle lens display.

With regard to the construction of electroluminescent displays, the invention is based on a prior art as represented in this area by publications by S. Tanaka et al from the Tottori University in Japan.

In a first work (S. Tanaka, H. Yoshiyama, J. Ni-shiura, I. Ohshio, H. Kawakami, H. Kobayashi, Digest of the 1988 SID Inter. Sy p., P. 293) results of sub- Searches for a full-color electroluminescent display on the basis of a white emission are presented, the color being achievable by optionally controlling such pixel elements in which the three basic colors are to be selected from a white emission by means of color filters. The structure of this electroluminescence test pattern resembled the rule in that a film package comprising a transparent electrode, a first single-layer or multi-layer insulator film, a single-layer or multi-layer active semiconductor film and a second single-layer or multi-layer film was placed on a glass substrate Insulator film and a second electrode made of metal. A simple and appropriate application of organic filters to the front of the glass substrate for these investigations is not acceptable in a large-scale implementation because the color filters are at least 1 mm thick from the emission layer. are separated and a good color impression only arises when viewed almost vertically, since a parallax occurs between the filter and the light source at an oblique angle.

According to a further work (S. Tanaka, H. Kawakami, K. Namamura, H. Kobayashi, Digest of 1989 SID Int. Symp., P.321), the color filters between substrate glass and transparent electrode were used to remedy this defect arranged and formed from inorganic multilayer interference filters. This solution avoids parallax, but results in color distortions at larger viewing angles due to the angle dependence of the transmission of the interference filter.

Special technological measures for the production of large format flat displays are e.g. known for plasma displays with a diagonal of approximately 50 cm (20 in.) or 84 cm (33 in.) by the work of H. Murakami et al. In Digest of the 1988 SID Intern. Symp., P. 142 to 145 and in Proc. of the 9 th Intern. Display Res.Conf., 16th to 18th October 1989 (Japan Display '89) Kyoto (Japan), p. 214 to 217 the thick film printing and the deposition of active phosphor material are emphasized. Electrodes and webs, each with uniform height and width dimensions, can then be built up in repetitive cycles of thick film printing processes and drying processes. An apparatus in which a scraper blade is moved over this layer was used to form a uniformly flat surface of a layer of phosphor material.

The aim of the invention is small, but above all large-format, electroluminescent specialist displays which enable two, multiple or full colors and are distinguished by high image quality, low power consumption and low weight, and cost-effective production by means of flow production Enabling and automation of the manufacturing processes with good compatibility of less complex technological operations.

The invention is therefore based on the object of specifying an arrangement for a flat electroluminescent display, in which case a thin-film structure with white emitter and with color filters is to be assumed, and in which the viewing angle is not caused by parallax or interference effects is restricted. The control of the pixels of the arrangement should take place, as is known per se, in the case of flat displays of a different type, but also with a pixel grid dimension already in the mm range. The manufacturing process should be able to be carried out in as few subsections as possible with operations for which similar or, if possible, no special conditions with regard to vacuum, temperature, clean room conditions etc. have to exist, and which make it possible to position structures in perform different layers with little effort.

The object is achieved in that in the case of an electroluminescent flat display which has a layer package carried by a substrate plate, in which two layers of electrically highly conductive materials are structured to form the rows and columns of a matrix of electrode pairs for selectively controllable pixel elements and are each adjacent to a layer of insulator material, between which there is a layer of active phosphor or semiconductor material which emits white light under the action of an electric field, and in which color filters for the pixel elements are in a further layer position, according to the invention the layer pair ¬ ket-carrying substrate plate is designed as the rear of the display, one in the layer package on the substrate plate Structured layer made of a metal as reflective electrodes, the first layer made of insulator material, the layer made of active phosphor or semiconductor material, the second layer made of insulator material and the second structured layer made of electrically highly conductive material as optically transparent electrodes in the order mentioned are arranged, and the color filters cover the transparent electrodes and form the further layer which is located on the front of the display facing a viewer.

This solution is based on the idea essential to the invention of reversing a MISIM structure (M = metal; I = insulator, S = semiconductor) with regard to the viewing direction and starting from reflective metal electrodes on a substrate plate forming the rear front of the flat display, then arrange the insulator and semiconductor films and the film for the transparent electrodes, eg from IT0 (indium tin oxide). This creates the conditions for covering the transparent electrodes pixel by pixel with the best available absorption filters, without parallax or interference effects restricting the viewing angle.

Thus, existing deficiencies can be avoided, which are due to the fact that sufficiently good absorption filters on an inorganic basis, which resist the process temperatures during the production of MISIM structural layers to be arranged above them, are not known. At least for such filters, which, for example, allow blue to pass through but are supposed to absorb red, with adequate thicknesses of up to about 1 micron, no sufficient color saturation is achieved. The arrangement according to the invention of relatively thick, good color-saturating inorganic or organic absorption filters on a film package which is already essentially finished, in any case that no longer requires treatment at high temperatures, but offers possibilities of considerable importance.

Forms of embodiment of the invention can namely differ significantly both in terms of the color and the format of a flat display and otherwise have a large number of identical or largely similar structural details. When building the MISIM structure for the white emitter, the layer thicknesses and the materials of the solids are independent of whether it is the version as a variant for e.g. small-format, two-color alphanumeric representations or as the most convenient variant for large-format, full-color moving image reproduction in the HDTV standard. The image pixel dimension in the mm range is decisive for the dimensions of the electrodes. A full-color display requires triple color filters, i.e. it requires an area of e.g. 1 mm for each pixel. If only two colors are required per pixel in a flat display and the electrodes are designed in the same dimensions as for a full-color display, the is reduced

2 space requirement per pixel to around 0.44 mm. In all cases, the pixel matrix can be controlled in series or columns. For a full-color display, the elements of the color triples per pixel must be very easy to mix, a two-color or multi-color flat display with a lower number of brightness levels of individual colors that are not to be mixed within a pixel, however, requires a less complex one in this respect Control.

In an advantageous first embodiment of flat displays according to the invention, the first layer, structured as reflective electrodes, made of electrically conductive material, can have a chrome layer, and the second layer, structured as transparent electrodes, made of electrically conductive materials. a layer of indium-doped tin oxide, the layer of insulating material arranged adjacent to the respective layer of electrically good conducting material is formed in one or more layers and the layer of active phosphor or semiconductor material is in one or more layers and contain a layer of Sr (S, Se): Ce and / or SrS.Eu.

A second embodiment, which is also advantageous as a further development of the aforementioned, relates to forming the reflective electrodes in strips and arranging them along an axis of symmetry of the substrate plate, and also to forming the transparent electrodes in strips, but orthogonally to the reflecting electrodes to be arranged continuously and as elements in two or more different colors and in a repetitive pattern for pixels, to form the color filters in strips and to arrange the transparent electrodes covering and in their direction, with each crossing point of one of the reflective electrodes and one of the transparent electrodes Electrodes forms a freely selectable pair of electrodes in a two-color, multi-color or full-color display.

For this purpose, it can be provided as a further embodiment that the elements of the pixels are arranged in a repeat pattern of color squares. The advantage of this is that, for example for weakly transmitting color filters, in particular for blue, in the case of pixels which function as a color triple, a larger radiation area is available for such colors. In the case of two-color displays, the brightness of each of the two colors can be graduated more finely in this way. In the case of all flat displays according to the invention and their forms of formation, a capping forming the front of the display can be arranged particularly expediently on the layer layer of the color filter. This serves as protection against contact and corrosion for the flat display and, in the case of smaller-sized flat displays, also for stabilizing the MISIM layer package and the color filter layer on the substrate plate.

A further embodiment, which can be also applied to all inventive flat panel displays in the aforementioned embodiments advantageously, be¬ runs out to trigger the ^'displays only on one longitudinal and one transverse side for the rows or columns of Arrange matrix electronic circuits. This is favorable both for a hybrid and for an integrated construction of flat displays and their associated electronic circuits.

Closely related to this and due to the fact that flat-panel electroluminescent displays as solid-state structures do not require any side closing edges, there is finally a particularly advantageous embodiment in which four displays are joined together to form a flat screen. Flat screens, which are to be formed from a large number of lined up and / or lined up displays, then require a special connection technology between the displays if the pixel grid dimension is to be strictly adhered to.

For the production of a flat electroluminescent display, the problem to be solved is to form a layer package on a substrate plate, which has a first structured layer made of electrically highly conductive material, a first layer made of insulator material, and a middle one Has layer of active phosphor or semiconductor material, a second layer of an insulator material and a second structured layer of electrically highly conductive material and a further structured layer layer in which color filters for the pixel elements are arranged.

The method according to the invention provides for the substrate plate, the lower surface of which subsequently forms the rear front of the display, to be provided on its upper surface with reflective electrodes made of metal, as the first structured layer made of electrically highly conductive material, then via and between the reflective ^'electrodes, the first layer of insulating material, above the middle layer of active fluorescent or Halbleiterma; or more layers to separate, and erial dar¬ off via the second layer of insulator material, each ganz¬ surface and, on the second Layer of insulator material to deposit an electrically well-conducting and optically transparent material as a first homogeneous layer over the entire surface, now the further layer layer with the color filters on the front of the display over the initially still full-surface layer made of the optically transparent and electrically well-conductive material build up and then To form transparent electrodes covered by color filters, the structure of the color filters can be used as a mask for self-adjusting structuring of the layer made of the optically transparent, electrically conductive material.

Devices and conventional technologies have already been tried and tested for the production of monochrome electroluminescent displays with pallet dimensions of 700 mm length and width. These technologies are readily adopted for those process stages that focus on the formation of the layers of the insulator materials and the active Obtain fluorescent or semiconductor material. Such material layers can all be produced using the same technology, for example by reactive deposition from the metals, by sputtering, by deposition from organometallic compounds, etc.

The deposition of an optically transparent, electrically highly conductive material also belongs to conventional, already tried-and-tested technologies for the production of electroluminescence thin-film displays. In the method according to the invention, however, this layer is not the first but the last of the MISIM structure.

The technological section at the beginning of the manufacturing process according to the invention, in which a metal layer is to be produced and structured as the first layer of the MISIM structure, has extensive similarities to operations that also apply to the production of flat plasma displays, specifically for their rear part , are to be carried out. In both cases, it is sufficient to free the substrate plates from coarse bumps, particles and streaks, so that the surfaces of the substrate plates can then be provided with electrodes made of metal.

In the last section of the manufacturing method according to the invention, both the color filters are built up and the electrodes are structured in the layer made of the optically transparent, electrically highly conductive material. The operations which take place in this section result in the color filters being on the one hand very close to the white light emitter layer and on the other hand directly on the front of the display, that is to say they are easily accessible there without the end of production allow further final finishes. It is essential that the operations to build up dyeing filter and for structuring transparent electrodes are in the closest possible functional connection with each other and self-adjust the structures of the color filters and the transparent electrodes they cover. The requirements for compliance with tolerances of these structures are low; it is only necessary to ensure that structuring edges are not interrupted.

The production of flat electroluminescent displays thus takes place according to the method according to the invention in a few sub-sections, each with operations to be carried out optimally and in their overall effect. Structuring is only necessary at the beginning and at the end of the manufacturing process. In between, solid layers of solid must be deposited on top of each other.

Embodiments of the manufacturing method according to the invention primarily relate to measures which are related to the structuring of layers. With regard to the production of reflective electrodes made of metal, it is particularly favorable to transfer a prefabricated decal image from a carrier film to the substrate plate. This decal can be e.g. fix sufficiently on the substrate plate by melting.

In a corresponding manner, in the case of embodiments of the invention, the color filters can also be transferred as a prefabricated decal from a carrier film to the still unstructured layer of optically transparent, electrically highly conductive material. In this case, the color filters can be fixed, for example, by means of an organic adhesive which, when cured, must be resistant to means for removing the optically transparent, electrically conductive material when the transparent electrodes are structured. According to another embodiment of the method according to the invention, the generation of structures for electrodes and color filters in a geometrically simple, regular configuration can also take place by relative movement between the substrate plate and an apparatus which carries out the operations for structure formation. Such operations include, for example, the application of structures, already in their final design, or the removal of areas of layers previously applied over the entire surface.

As a result of the self-adjustment of color filters and the transparent electrodes covered by them, and of the reflecting and transparent electrodes which result from self-resulting intersection points without special measures in self-reflecting flat-panel electroluminescent displays according to the invention, the required dimensional accuracy can be achieved in this way without any particular effort.

The above-mentioned embodiments of the manufacturing method according to the invention are obviously not only applicable to flat electroluminescent displays; these embodiments thus designate objects which, in addition to their independent inventive significance, also have a further scope of protection.

Further advantageous embodiments deal with the subsection for the construction of the color filter and the structuring of the transparent electrodes. After the sequence of the operations to be carried out, the structure of the layer layer with the color filters is first explained in more detail.

As already mentioned above, the construction of the color filter can start with a decal that has been prepared elsewhere or on the still unstructured th layer of the optically transparent, electrically conductive material. In such cases, the finished structure of the color filter forms the mask, which is then used for the self-adjusting structuring of the transparent electrodes. In particular in the case of color filters made of inorganic materials, each color is already defined at this time. Depending on the respective possibilities and requirements, the structured filters can be constructed in the individual colors simultaneously or separately for each color.

Another embodiment of this sub-section of the method according to the invention offers the advantageous possibility of first applying a full-surface layer of color-neutral, organic material over the layer of optically transparent, electrically highly conductive material, which is initially full-surface, to build up the layer layer with the color filters, then to generate the structures of the color filters and then - or in a common process step - the structures of the transparent electrodes and finally to color the previously structured and still color-neutral color filters with dyes in the desired colors.

For this coloring, a particularly preferred embodiment provides for the individual dyes to be introduced electrochemically into the color filter and for this purpose to selectively use the relevant transparent electrodes.

Of course, in addition to the above-mentioned embodiments of the method according to the invention, conventional processes for the construction of the color filters are also important, particularly when more complicated repetition patterns are required for the color filters. The layer layer with the color filters can then be screen printed, for example. drive or also build up in lithography operations separate for each color shade, in particular using colored photoresists.

Finally, it is expedient to provide the flat display with a capping after completion and functional test, which forms the front of the display.

Embodiments of the invention, which are to be regarded as particularly favorable and include details of the structural design and / or measures for the production method of the flat displays according to the invention, are explained in more detail below with reference to the schematic representations in the drawings. Show:

1: the layer structure of an electroluminescent flat display with color filters, as a detail in a perspective view; 2: Similar to FIG. 1, the layer structure, but in sections showing the layers of the MISIM film package and the color filters generated;

3: an electroluminescent flat display with control

Electronics; 4: a flat screen which is formed from four displays which are joined together; 5 shows a section of a pixel matrix in which the reflective electrodes, the transparent electrodes and the color filters are formed in strips; 6: a detail similar to FIG. 5, but with wider stripes for blue color filters than for red and

Green color filter; 7 shows a variant for the formation of color triple pixels in the form of color quadruples; Fig. 8: another variant with the effect as in Fig. 6 or Fig. 7;

9: two forms of formation for pixels of a two-color flat display;

10: a possibility of structuring pixels with line color filters, reflecting electrodes for the individual colors and transparent electrodes for pixels; 11: a possibility of structuring pixels with column color filters, reflecting electrodes for pixels and transparent electrodes for the individual colors and

12: a representation for the implementation of operations for the generation of regular structures by relative movement between the substrate plate, with layers possibly already thereon, and respective apparatuses for the formation of structures.

In the exemplary embodiment of the invention shown in FIG. 1, a strip structure of reflective electrodes 2 made of chromium is initially on a substrate plate 1 made of glass. This structured layer of metal as well as the single or multi-layer films, i.e. a first layer of insulator material 3, a homogeneous layer of active phosphor or semiconductor material 4 that is single or multi-layered over the entire surface - to achieve a white emission e.g. a film made of Sr (S, Se): Ce and a film made of SrS: Eu -, a second layer made of insulator material 5 and a homogeneous layer 6 made of electrically conductive and optically transparent material, e.g. made of indium tin oxide (ITO), represent the MISIM structure.

Three, the primary colors, run orthogonally to the strips of the reflective electrodes 2 on the layer 6 R (red), G (green), B (blue) transmitting color filters 7R, 7G, 7B formed from inorganic or organic materials, which were applied alternately in strips and by themselves or by means of a protective layer for the removal of material resist when structuring transparent electrodes 8. Each three adjacent color strips forming the basic color filters 7R, 7G, 7B are repeated in a grid dimension of, for example, 1 millimeter, which also applies to three adjacent reflecting electrodes 2. As a result of the ITO etching / removal then carried out, the transparent electrodes 8 are formed in strips from the layer 6, one of the color filters 7 in the primary colors R, G, B being assigned to each strip in a self-adjusting manner. A subsequently applied capping 11 (not shown) provides the flat display 10 with sufficient protection against contact and forms its front, as indicated by an eye 9 of a viewer.

The manner in which the structures for reflecting electrodes 2 and color filters 7 are formed, and also using the transparent electrodes 8, has already been described above. As an example and representative of all these possibilities, only the screen printing method is mentioned here.

The structures shown in FIG. 2 are also intended to clarify the sequence of the method steps for the production of such flat displays. The reflective electrodes 2 made of chromium are located on the substrate plate 1, here formed as wide strips with a grid dimension of, for example, 1 mm. The layer of insulator material 3 covers the reflective electrodes 2 and also fills the parting lines between them. The homogeneous layer above it consists of active phosphor or semiconductor material 4 and forms the white light emitter layer. Thereon This is followed by the second layer of insulator material 5 and then the layer 6 of optically transparent, electrically highly conductive material, which is initially applied over the entire surface. The stripe-shaped color filters 7R, 7G, 7B are orthogonal to the reflecting electrodes 2 and have a raster dimension of 1 mm for this repeating pattern on the layer 6, which is initially still unstructured.

The thickness of the MISIM layer package on the substrate plate 1 is approximately 2 μm in total. Approx. 50 nm are allotted to the reflecting electrodes 2, approx. 200 nm to 300 nm to the layers of the insulator materials 3, 4, approx. 1,000 nm to the layer of the active phosphor or semiconductor material 4 and almost 6 nm on the layer 6 made of optically transparent, electrically highly conductive material.

The structure of the color filters 7R, 7G, 7B serves as a mask for structuring the transparent electrodes 8 in the layer 6. The color filters 7 thus cover the transparent electrodes 8 in a self-adjusting manner and are located on the front of the viewer, symbolized by an eye 9 Flat displays 10.

With regard to the controllability of individual pixels 12, the following can already be seen from FIG. 2: If one of the reflecting electrodes 2 has a bias voltage just below the threshold voltage, for example U. = -150 V, and three transparent electrodes 8 are obtained at the same time , each of which is assigned to a strip of the color filters 7R, 7G, 7B, voltage values of, for example, U _R = + 50 V, U- = + 40 V and U-, = + 60 V, or voltage pulses with different durations, is used for exactly one Pixel 12, the three crossing points of the voltage-reflecting reflective electrode 2 and transparent electrodes 8, the white light Emission in the layer of active fluorescent or semiconductor material 4 in three intensity levels in accordance with the voltage potentials resulting in terms of magnitude or the duration of the control pulses in question locally limited to the areas of the prevailing electric fields. The colors traversed by the color filters 7R, 7G, 7B triggered pixels mix in accordance with their respective intensities and thus enable any desired color tone in the desired brightness.

In the flat display 10 shown in FIG. 3, electronic circuits 13, 14 drawn as blocks are provided on the longitudinal and transverse sides of the flat display 10 for the optional control of the pixels 12, some of which are indicated in the detail of the capping 11. These contain e.g. Column and row drivers. For row or column serial control, two circuit sets are provided in a manner known per se in one of the two electronic circuits 13, 14, one of which works in the write cycle, the other in the read cycle. The amplitude values or the control pulses of all pixel color elements of a row or a column of the matrix thus simultaneously arrive in the relevant row or column, which are switched on in time by the assigned electronic circuit 14, 13.

4 shows an exemplary embodiment of the invention for a flat screen with four mirror-symmetrically constructed flat displays IQ which are joined to one another without interruption of the grid dimension. This ability to connect and fit the flat display 10 is possible because an electroluminescent display as a solid -Buildings (all solid state) no locking edges required. A large format flat screen for high definition television, «where a ratio of height to width of 1: 1.7 is used, for example It is 1250 mm high and 2125 mm wide, so that four flat screens, each 625 mm high and 1065 mm wide, can be joined together. The respective pixels 12 are actuated simultaneously on each of the four flat displays 10, so that the maximum permissible duration of a control voltage or a control pulse for each pixel 12 in comparison with a flat display 10 occurs for the flat screen according to FIG. 4 the same number of pixels increases, but at the same time reduces the capacitive load of the drivers.

The embodiments of the invention thus meet the requirements for full-color displays, that is to say maximum requirements for the display devices for color television, in particular for high-definition television - HDTV. So far e.g. no full color suitability for computer applications, handheld or table-top devices or for other types of optically indicating information output, such as those for advertising purposes, traffic control devices and warning signs on streets or notice boards at train stations and airports, no high gradation of the brightness values and / or resolution is required, details can be easily modified.

Electroluminescent flat-panel displays can also be designed in many ways within the framework of the technical teaching according to the invention with regard to the implementation of selectively controllable pixels 12. 5 shows a section of a matrix of pixels 12 which consist of elements for the three primary colors R (red), G (green) and B (blue) and in which the electrode pairs at each pixel 12 each have a reflective electrode 2 and in each case three transparent electrodes 8 are formed. The electrodes 2, 8 and the color filters 7 are designed in the form of strips. The colors of the color filters can differ repeating pattern R, G, B, .... R, G, B, or for example also B, R, G, G, R, B, B, ..., may be arranged. As indicated by the two axis crosses (x, y), both arrangements are fundamentally equal. Not shown here (however, see FIG. 1) is an embodiment with three reflecting electrodes 2 per pixel 12.

FIG. 6 shows an embodiment variant in which, in view of the comparatively high absorption of blue filters, their area is designed to be larger than that of the green and red filters. Since the human eye perceives a pixel 12 at the intended - normal - viewing distance as the smallest resolvable unit, its color elements merge, so that their repetitive patterns can be chosen arbitrarily, e.g. with the wide stripe of the blue filter B in the middle between green filter G and red filter R or on the side of the green / red filter pair G / R.

7 and 8 show R-G-B pixels 12, which function functionally as color triples, constructively - cf. Fig. 7 - but are designed as a quadruple. Here, too, the higher absorption of the blue filters is compensated for by a larger radiation area. The repeat patterns extend two-dimensionally. As a result, the number of color filter strips per pixel 12 or the pixel pitch in one direction is reduced. For this, the coloring of the color filter strips, compare in particular FIG. 7, and also the control and the formation of the structure for the reflecting electrodes 2 are more complex.

FIG. 9 shows, in general form, two possibilities for the formation of pixels 12 of a two-color flat display on the basis of a white light electroluminescence emitter with color filters 7F1 and 7F2. , 12 are to be provided for each pixel: for example: two strips of reflective electrodes 2 and a strip for the transparent electrode 8, covered by two immediately adjacent strips for the color filters 7F1, 7F2; or: one strip for the reflective electrode 2 and two strips for transparent electrodes 8 each covered by color filter strips 7F1, 7F2; or: hereafter easily derived intermediate forms.

10, the stripe-shaped color filters 7R, 7G, 7B run e.g. in the direction of the lines of the flat display 10. In contrast to the structure shown in FIG. 2, a special structuring of reflecting electrodes 2R, 2B, 2G with three nested surfaces connected by webs is provided for this purpose in the variant shown here . The counter electrodes 8 can then be formed as wide strips corresponding to the pixel grid dimension.

The variant shown in FIG. 11 corresponds to the structure shown in FIG. 2. Here the stripe-shaped color filters 7R, 7G, 7B should lie in the direction of the columns of the flat display.

As already indicated above, the flat displays 10 can usually be constructed and used either with color filter strips running in the row or in the column direction. In this context, it should also be mentioned that as strip-shaped structures for electrodes 2, 8 and color filter 7, curved designs can also be considered, for example for the purpose of radiation-optical corrections in the case of large flat and concave curved electroluminescent flat displays 10.

With the aid of FIG. 12, particularly important production-technical measures for the production of regular structures in flat displays of different types are to be used. become clear. The structures, as are required in the technical teaching according to the invention for reflective electrodes 2, transparent electrodes 8 and color filters 7, can generally be designed very simply in terms of their geometry. Furthermore, flat displays should also be used as large-area structures with dimensions in the meter range which are to be provided with such structures. In addition, the tolerance requirements for these structures are not excessively strict. All of these prerequisites allow structures that are geometrically simple to design to be formed in operations that take place in a relative movement between the workpiece and the apparatus for the structure mapping. In the case of the present invention, the workpiece is the substrate plate 1 with the layer to be structured thereon, the apparatuses 15 for imaging or forming the structures contain, for example, a template, the number and size of parallel strips being slit or the pattern to be repeated (see, for example, FIG. 10 for the reflecting electrodes 2) is punched out once as a positive or negative containing.

Devices currently used for structuring electronic circuits, on the other hand, work according to the "step and repeat" principle, that is to say they place a small format layout in the x and y directions, once present. The application of this principle in the manufacture of flat displays according to the invention and also of other types, e.g. in the case of plasma displays, would mean a significantly higher production outlay in the relevant technological subsections and would also require special measures which are not required or are not permitted in the manufacture of electronic circuits on wafers and which ensure that the layout images touch or overlap as desired.

Claims

1. Electroluminescent flat display, which has a layer package carried by a substrate plate, in which two layers of electrically highly conductive materials are structured to form the rows and columns of a matrix of electrode pairs for selectively controllable pixel elements and each have a layer Insulator material are adjacent, between which there is a layer of active phosphor or semiconductor material which emits white light under the action of an electric field and in which color filters for the pixel elements are located in a further layer position that the substrate plate (1) carrying the layer package is designed as the rear of the display (10), that in the layer package on the substrate plate (1) the structured layer made of a metal as reflecting electrodes (2), the first layer Insulator material (3), the layer of active L Euchstoff- or semiconductor material (4), the second layer of insulator material (5) and the second structured layer (6) of electrically well conductive material as optically transparent electrodes (8) are arranged in the order mentioned, and that the color filter (7) cover the transparent electrodes (8) and form the further layer layer which is located on the front of the display (10) facing an observer (9).

2. Elektrolu ineszeπz flat panel display according to claim 1, characterized in that the first, as reflective electrodes (2) structured layer of electrically highly conductive material is a chrome layer, that the second, as transparent electrodes (8) structured rier layer (6) made of electrically highly conductive material is a layer made of indium-doped zinc oxide that the layers of insulating material (3, 5) which are arranged adjacent to the respective layer of electrically well-conductive material are formed in one or more layers, and that the layer of active phosphor material or semiconductor material (4) is formed in one or more layers and contains a layer of Sr (S, Se): Ce and / or SrS: Eu.

3. Electroluminescent flat panel display according to claim 1, characterized in that the reflective electrodes (2) form stripes and are arranged along an axis of symmetry of the substrate plate (1) that the transparent electrodes (8) are also stripe-shaped, but orthogonal to the reflecting electrodes (2) are arranged so that the color filters (7F1, 7F2, ... 7Fn) as elements in two or more different colors (Fl, F2, ... Fn) and in a repeat pattern for pixels (12) ) formed in strips, covering the transparent electrodes (8) and arranged in their direction and that each crossing point of one of the reflecting electrodes (2) and one of the transparent electrodes (8) thus a freely selectable electrode pair in a two-, multicolor or full-color display (10) forms.

4. Electroluminescent flat display according to claim 3, d a d u r c h g e k e n n z e i c h n e t that the elements of the pixels (12) are arranged in a repeating pattern of color squares.

5. electroluminescent flat panel display according to claim 1, dadurchgekennz e. Inet that on the layer of the color filter (7) one of the pre derfroπt of the display (10) forming capping (11) is arranged.

6. Electroluminescent flat display according to claim 1, d a d u r c h g e k e n n z e i c h n e t that for driving the display (10) are arranged only on one longitudinal and one transverse side for the rows or columns of the matrix electronic circuits (13, 14).

7. electroluminescent flat panel display according to claim 6, d a d u r c h g e k e n n z e i c h n e t that four displays (10) are joined together to a flat screen.

8. Method for producing an electroluminescent flat display, wherein a layer package is formed on a substrate plate, which has a first structured layer made of highly electrically conductive material, a first layer made of insulator material, and a middle layer made of active phosphor or semiconductor material , has a second layer made of an insulator material and a second structured layer made of electrically highly conductive material and a further structured layer layer in which color filters for the pixel elements are arranged, characterized in that the substrate plate (1), the lower surface of which subsequently follows the rear front of the display (10) forms, on its upper surface with reflective electrodes (2) made of metal, as the first structured layer made of electrically highly conductive material, that the first layer is then above and between the reflective electrodes (2) made of insulator material (3), the middle one above Layer of active fluorescent material or semiconductor material (4) and above that the second layer of insulator material rial (5), in each case over the entire surface and in one or more layers, that an electrically highly conductive and optically transparent material is deposited over the second layer of insulator material (5) as an initially full-surface, homogeneous layer (6) is that now the further layer layer with the color filters (7) on the front of the display (10) is built up over the layer (6) made of the optically transparent and electrically conductive material, and then, for training purposes transparent electrodes (8) covered by color filters (7), the structure of the color filters (7) is used as a mask for a self-adjusting structure of the layer (6) made of the optically transparent, electrically highly conductive material.

9. The method as claimed in claim 8, so that reflective electrodes (2) made of metal are transferred as a prefabricated decal from a carrier film to the substrate plate (1).

10. The method of claim 8, d a d u r c h g e k e n n z e i c h n e t that color filters (7) are transferred as a prefabricated decal from a carrier film to the still unstructured layer (6) made of optically transparent, electrically highly conductive material.

11. The method according to claim 8, characterized in that the generation of structures for electrodes (2) and color filters (7) in a geometrically simple regular design by relative movement between the substrate plate (1) and an apparatus is carried out which carries out the operations for structure formation.

12. The method according to claim 8, characterized in that to build up the layer layer with the color filters (7) first a full-surface layer of color-neutral, organic material above the initially full-surface layer (6) made of optically transparent, electrically conductive material is applied that the structures of the color filters (7) are then produced, that the structures of the transparent electrodes (8) are then produced and that finally the previously structured and still color-neutral color filters (7) are colored with dyes in the desired colors .

13. The method according to claim 12, so that the structures of the color filters (7) and the transparent electrodes (8) are produced in a common process step.

14. The method according to claim 12, so that the individual dyes are introduced electrochemically into the color filter (7) and the relevant transparent electrodes (8) are used selectively for this purpose.

15. The method according to claim 8, characterized in that the layer layer with the color filters (7) is built up in the screen printing process.

16. The method according to claim 8, d a d u r c h g e k e n n z e i c h n e t that the layer layer with the color filters (7) in for each

Hue separate lithography operations is built.

17. The method according to claim 15 or 16, d a d u r c h g e k e n n z e i c h n e t that colored photoresists are used for the construction of the color filter (7).

18. The method according to claim 8, so that the flat display after completion and functional test is provided with a capping (11) which forms the front of the display (10).