EP0456783B1 - Elctronic display device - Google Patents

Abstract

The device includes at least one electro-optical display means, such as a liquid crystal cell, a number of basic patterns linked to said electro-optical display means and for the most part shaped, on the basis of a series of selected stylised alphanumerical characters, as a composite mosaic-type structure, the raster of which consists of the patterns which have heterogenous and complementary outlines and which are arranged to interlock like the pieces of a puzzle. The device is characterized in that the mosaic is crosshatched by optically passive stripes which partially cover some of the basic patterns and divide up the mosaic. This electronic display device can be used in devices for displaying alphanumerical characters and messages in public areas such railway station concourses or airports.

Description

The invention relates to an electronic display device intended to display particular signs, such as in particular alphanumeric characters.

More particularly, it relates to a display device in which the active display means consists of one or more elements the optical characteristics of which can vary as a function of an electrical excitation signal, selectively controlled by a circuit of electronic control.

In the description which follows, reference will be made, to designate such elements, to an electro-optical cell of the liquid crystal type. As will be understood, the invention can be applied, in certain of its characteristics, for example to a display device comprising a set of light-emitting diodes, more generally designated under the British abbreviation "LED" or even to any other display device meeting the above definition.

Already known, according in particular to patent application FR-A-2 458 857, an electronic display device comprising a set of modules which are respectively constituted either by the electrodes of a liquid crystal cell, or by light-emitting diodes, and which have the form of straight lines arranged adjacent and at the end, by lines and by columns.

On the graphic level, this device is not entirely satisfactory, since it only allows characters "in sticks" to be displayed, that is to say in the form of contiguous lines.

What is more, this device is considerably limited since the modules do not allow indifferently the display, either of lower case or of upper case.

Furthermore, patent application EP 0 146 285 describes a display device of another type, that is to say structured essentially in the form of a matrix of points, with n rows and p columns (n being equal to 5 and p equal to 3, in this example).

The pixels of this matrix, that is to say the most elementary patterns which each form an individually addressable electrode, have been modified with respect to the pixels of the matrices. most classic points, only in order to increase the resolution. Thus, the designers of this matrix, while wanting to imperatively keep the qualities of low order matrices (typically 5x3), tried to increase the number of pixels. At that time, they therefore quite naturally started from a classic matrix form, comprising rectangular pixels, and in particular square pixels, by definition all identical and distributed in a homogeneous manner. The goal they had set for them led them to divide said pixels into four by cutting almost all of them almost identically, using two diagonals. The resulting structure therefore essentially consists of several repeating groups, each composed of four isosceles triangles. By observing the outline or the envelope of these groups, we can clearly see the appearance of the original rectangles whose meeting constitutes the grid or grid of the matrix.

It is therefore noted that the structure of this device remains in a very regular and orderly design, with a strict and almost identical repetition of the groups and of the pixels, meeting the definition of displays of the matrix type.

This particular design of electro-optical displays has major drawbacks. Indeed, the shape of the displayable characters is determined at the origin by the matrix diagram of the electrodes or pixels. Thus, starting from a rigid and imposed diagram the user has only the only possibility to select, in this given diagram, the pixels which are at his disposal to obtain a letter or a number. It is therefore impossible for him to visualize stylized characters since the capabilities of the device are confined to the original grid.

Consequently, although the device proposed in this patent application responds to the concerns of increasing the resolution of display devices of the matrix type by increasing the number of pixels, it is understood that it is very limited. Indeed, users, and therefore buyers of these devices, are now looking for the most aesthetic characters possible, close to a particular type or personalized writing.

Patent application EP 0 180 685, in particular in its last embodiment, partially addresses this problem by providing a device of a different design. The primary goal being to improve the aesthetics of the characters, the designers of this device started, no longer from an imposed diagram of electrodes, but from the result to be obtained, namely letters and numbers themselves for only then conform the electrodes.

This is why the pixels obtained are irregularly shaped and are arranged in a disorderly manner, without systematic repetition in rows and columns, these pixels having for the major part of them different contours.

This type of device is called "mosaic" because of its composite-looking structure, formed by many pixels with heterogeneous contours (rounded, straight, angled, ...), but complementary and in concordance, overlapping one in the others. It is noted that a logical and uniformly distributed distribution of the pixels or electrodes is not taken into account over the entire surface of the device, as opposed to the matrix structures defined above. This type of device is similar to the arrangement of the pieces of tinted glass that are found in the old stained glass windows of places of worship, especially in the West.

This device has major drawbacks.

First of all, we observe that irreparably the fact of stylizing the characters leads to an increase in the number of pixels, which very significantly increases the price of the finished and equipped device, insofar as it is necessary to associate with more sophisticated and "heavier" electronic circuits.

Furthermore, the characters obtained suffer from poor definition and they have, as will be explained below, defects formed by dots.

Indeed, and as it is very schematically represented in FIG. 2 of the appended drawings, it appears on the displayed characters, such as the "A" represented, dots or marks (referenced 10), these defects significantly affecting the appearance, and therefore the aesthetic quality of said characters.

In addition, "parasitic" lines, such as that referenced 11 in FIG. 2, appear next to, or even inside, the characters.

In fact, each elementary pattern being constituted by an electrode which is electrically isolated from the neighboring electrodes, it is necessary to connect each pattern to the electronic control system by its own electrical connection.

These connections are formed by tracks which are structured, like the electrodes, by a photolithographic process on a substrate covered with a conductive layer and they are therefore liable to vary the optical characteristics of the liquid crystal lying between them and a part. of the counter electrode. It is therefore understood that these connections can appear on the cell, at the same time as the alphanumeric characters displayed, which again contributes to deteriorating the quality of the display.

To overcome this, it has been proposed either to divide into several very thin branches 11a each of the connections at their overlap with the counter electrode, so as to make them invisible (FIG. 2a), or to design a counter electrode extremely complicated overlapping only the electrode and not the electrical connections.

In both cases, devices are obtained that are complicated to produce, and of course expensive.

In addition, the device according to this application EP 0 180 685, although providing a marked improvement in the appearance of the characters, still remains very limited since it does not allow the display of lowercase letters. It also has the essential drawback of having to be sized according to the size of the numbers and letters to be displayed. This dimension is therefore fixed and it can only be modified by changing the device already installed in favor of another, of different size.

The object of the present invention is therefore to respond to these drawbacks by providing an improved display device capable of visualizing much more stylized characters, for example close to the Helvetica Halbfett character, of excellent (aesthetic) definition. , free from defects of the type mentioned above, but in which the number of pixels can be minimized to obtain a low cost price.

The present invention also aims to provide a display device making it possible to respond to the problem of sizing the characters at a cost even as low as possible.

• au moins un moyen électro-optique d'affichage,
• des motifs élémentaires associés audit moyen électro-optique d'affichage, ces motifs élémentaires étant pour la majeur partie conformés, à partir d'une série de caractères alphanumériques stylisés et choisis, sous la forme d'une structure composite en mosaïque dont la trame est formée par lesdits motifs qui présentent des contours hétérogènes et complémentaires, disposés en concordance pour s'imbriquer les uns dans les autres, de façon similaire à un puzzle, ces motifs élémentaires formant des lignes et des colonnes délimitant des zones d'écriture caractéristique pour l'affichage de lettres ou de chiffres, caractérisé en ce que lesdits motifs élémentaires sont agencés dans lesdites zones d'écriture en groupes distincts dans lesquels ces motifs sont disposés entre eux à la limite de l'accolement et sont séparés par une distance d'écartement, prévue pour assurer l'isolation électrique de ces motifs l'un par rapport à l'autre, chaque groupe de motifs étant séparé du ou des groupes voisins par des bandes de séparation optiquement passives présentant une largeur nettement supérieure à la distance de séparation.

Thus, the subject of the invention is an electronic display device of the type comprising:

• at least one electro-optical display means,
• elementary patterns associated with said electro-optical display means, these elementary patterns being for the most part shaped, from a series of stylized and chosen alphanumeric characters, in the form of a composite mosaic structure whose frame is formed by said patterns which have heterogeneous and complementary contours, arranged in concordance to overlap each other, similar to a puzzle, these elementary patterns forming lines and columns delimiting zones of characteristic writing for the display of letters or numbers, characterized in that said elementary patterns are arranged in said writing areas in separate groups in which these patterns are arranged together at the edge of the contiguity and are separated by a spacing distance , provided to ensure the electrical isolation of these patterns from each other, each group of words yew being separated from the neighboring group or groups by optically passive separation strips having a width clearly greater than the separation distance.

• la figure 1 représente, de façon schématique et en coupe transversale, une cellule à cristal liquide d'un type classique formant, à titre d'exemple, le moyen actif d'affichage du dispositif selon l'invention,
• la figure 2 représente l'un des caractères alphanumériques affichés par un dispositif antérieur, cette figure mettant en évidence les défauts de ce type de caractère,
• la figure 2a est une vue très agrandie de l'arrangement des motifs élémentaires, pris au niveau du défaut 10 de la figure 2,
• la figure 3 est une vue de dessus d'une mosaïque selon un premier mode de réalisation, destinée à équiper le dispositif d'affichage selon l'invention, les motifs de cette mosaïque étant dans cet exemple constitués par des électrodes d'une cellule, telle que celle représentée à la figure 1,
• la figure 3a est une vue agrandie de la région IIIa de la figure 3,
• la figure 3b est une vue similaire à la figure 3, mais représentant les différents motifs élémentaires de la mosaïque associés à leur connexion électrique,
• les figures 4a à 4k représentent respectivement certains des caractères alphanumériques susceptibles d'être affichés par l'intermédiaire de la mosaïque selon le premier mode de réalisation, et
• la figure 5 représente en vue de dessus une contre-électrode selon l'invention,
• la figure 6 est une vue de dessus d'une mosaïque selon un deuxième mode de réalisaticn de l'invention,
• la figure 7 est une vue de dessus d'une trame de base destinée à former une mosaïque telle que représentée aux figures 3 et 6, et correspondant à la première étape de réalisation de cette mosaïque,
• la figure 8 est une vue de dessus d'une deuxième étape de fabrication de ladite mosaïque, comportant la trame de base de la figure 7 associée à une trame additionnelle,
• la figure 9 représente une troisième étape de fabrication de la mosaïque de la figure 6, dans laquelle les régions noircies correspondent à des séparations continues ou découpes disposées sur la mosaïque pour la hacher,
• la figure 10 représente la trame obtenue après l'étape représentée à la figure 9; et
• les figures 11 à 38 représentent des caractère alphanumériques qui peuvent être affichés notamment grâce à la mosaïque de la figure 6.

The invention will be better understood on reading the detailed description which follows, taken with reference to the appended drawings which are given solely by way of example, and in which:

• FIG. 1 shows, schematically and in cross section, a liquid crystal cell of a conventional type forming, by way of example, the active display means of the device according to the invention,
• FIG. 2 represents one of the alphanumeric characters displayed by a prior device, this figure highlighting the faults of this type of character,
• FIG. 2a is a very enlarged view of the arrangement of the elementary patterns, taken at defect 10 in FIG. 2,
• FIG. 3 is a top view of a mosaic according to a first embodiment, intended to equip the display device according to the invention, the patterns of this mosaic in this example being constituted by electrodes of a cell, such as that shown in Figure 1,
• FIG. 3a is an enlarged view of the region IIIa of FIG. 3,
• FIG. 3b is a view similar to FIG. 3, but showing the various elementary patterns of the mosaic associated with their electrical connection,
• FIGS. 4a to 4k respectively represent some of the alphanumeric characters capable of being displayed by means of the mosaic according to the first embodiment, and
• FIG. 5 represents a top view of a counter-electrode according to the invention,
• FIG. 6 is a top view of a mosaic according to a second embodiment of the invention,
• FIG. 7 is a top view of a base frame intended to form a mosaic as shown in FIGS. 3 and 6, and corresponding to the first step of making this mosaic,
• FIG. 8 is a top view of a second stage in the production of said mosaic, comprising the basic screen of FIG. 7 associated with an additional screen,
• FIG. 9 represents a third stage in the manufacture of the mosaic of FIG. 6, in which the blackened regions correspond to continuous separations or cutouts placed on the mosaic for chopping it,
• Figure 10 shows the frame obtained after the step shown in Figure 9; and
• FIGS. 11 to 38 represent alphanumeric characters which can be displayed in particular thanks to the mosaic of FIG. 6.

Referring to Figure 1, there is shown a liquid crystal cell which forms the active display means of the device according to the invention, this cell 1 comprising, in a known manner, a transparent front blade 2 and a transparent blade 3 and joined together by a sealing frame 4. The sealing frame 4 defines a sealed volume in which a mixture is trapped 5 composed of a liquid crystal and, for example, a dichroic dye. The front 2 and rear 3 blades which form the substrate carry on their internal face respectively electrodes 6a and a counter electrode 6b, the latter which are transparent being constituted for example by a mixture of indium oxide / tin. The front blades 2 and rear 3 generally also carry a dielectric layer and an alignment layer which are not shown here.

Furthermore, the electrodes 6a as well as the counter-electrode 6b have electrical connections which, like the latter, are structured by a photolithographic process on the blades 2 and 3, these electrical connections which are not shown here, being respectively connected to an electronic control circuit not shown. Furthermore, in this example, cell 1 further comprises an element 7 of the reflector-diffuser or transflector type, depending on the display mode that is desired.

The operation of such a cell is currently widely known. It will simply be specified here that when a potential difference is applied between one of the electrodes 6a and the counter-electrode 6b, the part of the liquid crystal which is between this electrode and this counter-electrode changes structure so that this part of the display cell changes optical characteristic, creating a difference in brightness between activated and non-activated parts, which produces optically contrasted areas.

As explained above, the devices currently known on the market include electrodes 6a cut and arranged in order to be able to display relatively aesthetic characters.

However, and as shown very schematically in Figure 2, some of the alphanumeric characters displayed through these devices have faults, referenced 10. These faults materialize in the form of dots or marks at which the cell does not seem to be activated, the displayed character appearing to be "eaten" in places.

It is therefore understood that this type of drawback provides a particularly unfavorable effect, detrimental to the commercial attractiveness of the device when it is known that this type of device is intended to allow display (for example of destinations) in public places. such as station halls or airports.

This type of defect gives the illusion of premature wear and gives many users the impression of poor quality.

In addition, we generally see appearing alongside or inside the characters displayed relatively fine lines which are visible when we approach the display device, these lines corresponding to the electrical connections referenced 11 in FIG. 2a.

To avoid the appearance of such lines, a technique consists in cutting the counter-electrode 6b in a particular way so that no part of this counter-electrode is opposite an electrical connection 11. However, each elementary pattern having its own electrical connection which leaves in the free space left on the substrate, between this pattern and the neighboring pattern, it is easily understood that the design of the counter-electrode 6b is all the more complicated, and that the latter is therefore all the more expensive.

As shown in FIG. 2a, another solution consists in dividing each connection 11 into several branches 11a, these branches which are thinner therefore being much less visible, at least from a certain distance.

Here again, it is understood that the production by photolithography of these branches considerably complicates the manufacture of the display means and also does not make it possible to reduce the cost of the cells.

In Figures 3 and 6, there is shown in top view the two embodiments of the mosaic according to the invention, the patterns of this mosaic which are generally called "pixels" being constituted in this case by electrodes 6a. By analogy, these patterns can be constituted by diodes electroluminescent arranged on a suitable support, or by any other display means which can be activated electrically.

The arrangement of the elementary pixel patterns according to the invention responds well to the definition of mosaic, and in particular of composite mosaic, since it will be noted that these patterns have heterogeneous and complementary contours, namely rounded, rectilinear or oblique with combinations indifferent, these patterns being arranged in concordance to overlap one another, similar to a puzzle. We note that all these patterns are arranged in an irregular and disorderly manner without any systematic repetition of rows or columns, in one direction or another.

The elementary patterns m ₁ to m _n of the mosaics of FIGS. 3 and 6 (all of which have not been referenced) are shaped and are associated with one another so that the device according to the invention can display a whole range of alphanumeric characters, such as the letters of the Latin alphabet in upper and lower case, some of the letters used in European languages such as Germanic or Nordic languages, as well as the numbers 0 to 9, all these characters can be associated with their respective accentuation, including understood the underlines. Advantageously, each mosaic of these two embodiments is shaped to be able to display characters close to the "Helvetica Halbfett" style.

In addition, the mosaic M of elementary patterns m _1-n makes it possible to display all the punctuation marks so that the combination of several mosaics M together, juxtaposed or superimposed in modules, allows the display of intelligible messages, made up as structured sentences or as a group of coded words.

It will be observed that thanks to a hashing of this mosaic, (operation which will be explained below), some of the elementary patterns m _1-n are found assembled in groups G ₁ to G _n , these elementary patterns in each group being combined very closely, at the edge of the abutment, a small spacing distance Y being left between them.

The groups of patterns G _1-n are arranged in rows L1 to L6 and in columns C1 to C5. The isolated elementary patterns m ₁ , m ₂ and m ₃ allow the accentuation of Germanic and Nordic characters. The elementary patterns m ₁ and m ₃ are aligned and are respectively provided in the extension of the columns C1 and C5. The elementary pattern m ₂ which has the appearance of a substantially rectangular ring is disposed substantially below the elementary patterns m ₁ and m ₃ and facing the central column C3.

Lines L1 to L6 of groups G ₁ to G _n delimit at least three characteristic zones A, B and C respectively, a last zone D forming the abovementioned accentuations.

Zone A is the zone for viewing or materializing a first size of capital letters, while zone B is the zone for viewing small letters. Zone C is, for its part, the zone allowing in particular the display of the end of the legs and the display of the underlines, the zones A, B and C each having five columns suitably aligned.

Zones A and B advantageously comprise, in the first embodiment of FIG. 3, respectively five and three lines of characteristic groups, this choice of odd numbers of lines allowing the display of letters or numbers such as "B", " 3 "or" 8 ", the hollowed parts 20 are centered with respect to a horizontal crossbar 22, as shown particularly in Figures 4g to 4i.

In addition, the fact of having an odd number of lines in area A of upper case and lines of area B in lower case makes it possible to display upper and lower case letters substantially centered, as shown in FIGS. 4b, 4d, 4f and 4g to 4k. This particular characteristic of the arrangement of groups G ₁ to G _n with respect to each other therefore makes it possible to display "balanced" characters with an entirely satisfactory aesthetic appearance.

Furthermore, in each of the distinct and characteristic groups G _{1 -n} , the spacing distance Y which separates each elementary pattern (for example the pattern m ₄ ) from the adjacent pattern (s), in this case the patterns m ₅ to m ₇ , is low, i.e. of the order of 10.10 ^-6 meters (10 µm) to 50.10 ^-6 meters (50 µm). This distance has the essential function of electrically isolating neighboring patterns and it forms the width of the insulation spaces Es on the mosaic. that separate the patterns from each other. The patterns in each group are therefore arranged relative to each other very closely, and seem, even at a small distance, contiguous to each other. As can be seen in the letters and numbers in Figures 4a to 4k, this distance distance Y does not appear in the characters displayed.

We can define each group G _{1 -n} as being formed by at least two elementary patterns joined together and separated from each other, at least in part, by an isolation space Es.

Preferably, the spacing distance Y is chosen as small as possible taking into account the feasibility conditions and the chosen yield.

In the preferred embodiment of the invention, illustrated in FIG. 3, each group of patterns at least in zones A and B has a spacing interval of rectilinear shape.

In addition, each characteristic group G ₁ to G _n is separated from the neighboring group or groups by separation bands b _1-n , each separation band being in fact provided, in the case of a liquid crystal cell, by l absence of a conductive layer on the substrate between the electrodes 6a of the neighboring groups; this substrate being constituted by the blade 2.

The separation strips b ₁ to b _n preferably all have the same width X, this width preferably being of the order of 1.2 × 10 ^-3 meters (1.2 mm). Typically, it is chosen equal to 1.5.10 ^-3 meters (1.5 mm).

Note that the value X, that is to say the width of the separation bands which form the different characteristic groups G ₁ to G _n , is in any case clearly greater than the value Y which is the width of the interval or isolation space Es left between the adjacent elementary patterns in the same group. In the present case, the value X is chosen between 25 and 120 times greater than the value Y.

It has been estimated that the value R which is the ratio R between the value X and the value Y (R = X / Y) gives satisfactory results when R is less than 15, in other words when the width of the bands of separation is 15 times greater than the spacing distance Y left between the patterns.

Preferably, the value R is chosen equal to 30, where X = 1.5.10 ^-3 meters (1.5 mm) and where Y is equal to 50.10 ^-6 meters (50 µm). For this purpose, it will be specified that preferably the distance of spacing Y is chosen to be less than 100 ^× 10 ^-6 meters (100 μm).

In general, in the embodiment of Figures 3 and 6, the mosaic according to the invention has a chopped structure such that the separation strips formed between two adjacent groups always have a width X which is greater than the spacing distance Left there between the motives of these groups.

In addition, in this embodiment, all the elementary patterns, whether in zone A or in zone B, are organized into groups; namely joined together in pairs, at least in part at the limit of joining. In the present case, the mosaic comprising 152 elementary patterns, only 5 of them being isolated, it can be determined that in the whole mosaic, approximately 97% of the elementary patterns are organized in groups.

This choice of organization in groups of course has important functional consequences, but also provides the mosaic M, namely the display device, the possibility of displaying characters of a very particular style, such as those shown in Figures 4a to 4k. The separation strips b ₁ to b _n constitute optically passive regions and form, between the groups G ₁ to G _n , preferential passages of the electrical connection elements 30, from the elementary patterns m _1-n to the periphery of the means d display, as shown in Figure 3b.

These separation bands b _1-n form clearly delimited free zones, as is very clearly shown in FIG. 3, so that it is quite easy to form the corresponding counter-electrode 6b represented in FIG. 5 in a corresponding manner. , this counter-electrode 6b being shaped so that its "cut" areas 40, which correspond to the absence of a conductive layer, are arranged opposite the separation strips in which the electrical connections are made. Thus, it is understood that these regions are optically passive and that the electrical connections 30 do not appear on the display device when viewing the alphanumeric characters.

In addition, the mosaic M, namely the arrangement of the different elementary patterns m _1-n therebetween, is provided in such a way that at most four separation bands b _1-n intersect on or in the active means d 'display. The separation strips b _1-n , at least 'at their point of intersection I (Figure 3a), are angularly offset from each other by an angle α greater than 60 degrees.

The value of this angle α corresponds to that from which the appearance of defects, as will be defined below, begins to decrease significantly.

Preferably, the angle α is at most equal to 90 degrees. It should also be noted that in the preferred embodiment, the outer contour of each group of patterns G _1-n is substantially rectilinear, this contour preferably being substantially rectangular.

The bands b _1-n are in fact formed by continuous partitions or cutouts S ₁ to S _n which are formed on the major part of the display means, these continuous partitions S ₁ to S _n passing through the mosaic from start to finish. to open its lateral edges respectively right and left, and its upper and lower edges. This is particularly true in areas A, B and C for vertical partitions S ₁ to S ₄ , and in areas A and B for horizontal partitions S ₅ to S ₈ .

Be that as it may, throughout the mosaic, the separation bands b ₁ to b _n and the continuous separations or cutouts S ₁ to S _n are organized perpendicular or parallel to the direction of reading L of the characters on the mosaic.

With reference to a rectilinear and horizontal reading, it can be specified that the continuous partitions or cutouts S ₁ to S ₇ and the separation strips which they form can be defined as being oriented in essentially vertical and horizontal directions.

The display device according to the invention makes it possible in particular to eliminate the defects such as the dots or marks 10 which appear on the characters displayed by the devices currently known. Reference will now be made to FIG. 2a which shows in detail the arrangement of the elementary patterns of a known display device.

The appearance of faults 10 on such an arrangement can be explained by the combination of several phenomena.

First of all, at a short distance from the display device, the defects can be geometrically represented as an arc of a circle or a circle of radius R1, the circle being tangent to the ends or points of the various elementary patterns which converge towards the point of intersection i . In the present case, it is observed that the radius R1 is already greater than the spacing distance a which is left between the different elementary patterns. Thus, even at a short distance, the defect 10 appears to be already predominant with respect to the intervals which are left between the patterns, this defect in addition to these intervals appears in the same optical mode, which is different from that of the characters displayed, that is to say in a contrasting manner with respect to these characters.

At a greater distance, there occurs at the converging ends or points of the different elementary patterns an optical "erosion" phenomenon, that is to say loss of definition, the eye tending to no longer discern these points but to see rounded edges f .

Thus, the defect 10 at this distance increases considerably to materialize in the form of a circle of radius R2, this radius R2 being very much greater than the radius R1 of the defect which is visible at a short distance.

Thus, at a greater distance, the difference between the interval A and the radius R of the defect 10 increases, so that this defect 10 now appears as very preponderant with respect to the interval referred to above.

In contrast, in the configuration of the mosaic according to the invention, it is observed as shown in FIG. 3a that at a short distance the circle envelopes the point of intersection I at the level of the separation strips for example b13, b18, b19 and b20, has a radius r ₁ of a value less than the width X of the separation strips b _13,18-20 .

Thus, the envelope circle does not appear at a short distance and no longer forms a defect, since it is no longer preponderant with respect to the width of the separation bands b _1-n .

Furthermore, at a great distance the optical "erosion" is less great since for the same arc of a circle f , this arc of a circle f tends to approach considerably the points or ends of the groups G _1-n .

Thus, the envelope circle of the point of intersection I has a radius r ₂ of value substantially equal to the width X of the separation strips b _1-n . There is therefore almost no defect in the alphanumeric characters displayed with such a configuration, whether at a short distance or at a long distance.

Furthermore, it has also been observed that the definition of the characters and the readability are improved when the separation bands b _1-n and more particularly the continuous separations or cuts S ₁ to S _n which form the hash of the mosaic are oriented parallel and / or perpendicular to the reading direction of the displayed characters, the mosaic M being oriented over a whole panel display assembly, in the direction in which it is represented in FIG. 3, namely vertically.

It has also been observed that this arrangement improves the aesthetics of the characters displayed.

It will also be specified here that this mosaic M offers, thanks to its configuration, an appreciable aesthetic characteristic in that the accentuation elements for lower case letters (see FIGS. 4d to 4f) are arranged in the area A for viewing or materializing upper case letters. Thus, the accentuation elements of lower case letters are practically attached to these lower case letters, as is moreover provided for in the various alphabets, such as the Latin alphabet. Again, this possibility is explained by the arrangement in groups of elementary patterns. As the addition of additional elementary patterns within the same group is made possible thanks to the almost contiguous arrangement of the elementary patterns in this group, the accentuation elements cannot be distinguished in the body of a capital alphanumeric character which use this group to be viewed, as shown in the characters in Figures 4d to 4f.

Furthermore, it will also be specified that the separation strips b _1-n and therefore the continuous or cut-out separations S ₁ to S _n are arranged so that their points of intersection I are in outside the materialization regions of the branches of the characters, which appear vertically or horizontally.

Referring now to Figure 6, there is shown a composite display mosaic according to a second embodiment according to the invention.

The mosaic according to this embodiment comprises four continuous partitions or vertical cuts oriented perpendicular to the direction of reading L, as well as three continuous partitions or cuts S5 to S7 oriented parallel to the direction of reading L, that is to say defined as being horizontal. In this embodiment, the seven continuous partitions or cutouts which form the hash of the mosaic M have a width X, of a value equal to those mentioned above.

Referring now to Figures 7 to 10, we will now explain by what process we made the frames of the mosaics of Figures 3 and 6, and how was performed the hash of this mosaic into strips, that is to say in optically passive partitions or cuts.

Referring therefore now to Figure 7, there is shown a basic frame T ₁ , called the first frame, which constitutes the starting structure of the mosaic according to the invention. This basic frame T ₁ is intended to form the area B which allows the display of lowercase letters, as well as the display of a first set of small numbers.

Very advantageously, and as can be seen in FIG. 8, this basic frame T ₁ has been partially reproduced, in particular its upper part referenced T ₂ has been reproduced. The dashed line L _C represents the upper part of the base frame T ₁ which has been reproduced and then "glued" above the base frame T ₁ . It will be specified that the cutting line L _C , to duplicate the base frame, has been positioned so that after joining the two frames T ₁ and T ₂ the oblique isolation spaces come into concordance, which will subsequently allow the display of characters of different dimensions, inside a single mosaic. For this purpose, the cutting line L _C has been positioned at the intersection of the insulation space Es oriented obliquely.

After having obtained this duplicated structure of the base frame, in particular after having obtained an additional frame known as the second frame T ₂ which is arranged above the first frame ₁ , the resulting frame T ₃ is chopped by the continuous separations or cuts S ₁ to S _n , arranged in the orientation explained above. As can be seen in FIG. 9, the continuous separations or cutouts then completely compartmentalize the resulting frame T ₃ since they cross most of the mosaic according to the invention and thus form different groups of elementary patterns in the mosaic. As can be seen in FIG. 9, and in comparison with FIG. 8, the partitions or cutouts S ₁ to 5 ₇ partially cover certain elementary patterns of the weft T ₃ . In addition, these optically passive partitions or cutouts are arranged so that they completely overlap and mask the elementary patterns of smaller areas, which have been blackened in FIG. 9 for a better representation of the drawings. Since these strip separations or cutouts S ₁ to S ₇ are optically passive and correspond to an absence of electrode surface, the elementary patterns of smaller surface are eliminated and no longer need to be associated with an addressing which poses problems both in terms of electronics and in terms of electrical connections.

Advantageously, the mosaic according to the invention comprises at least two horizontal partitions or cutouts referenced S ₅ and S ₆ , and which are very advantageously placed in the vicinity of zones in which the density of the elementary patterns is the greatest. These areas are referenced respectively 100 and 120. Preferably, these partitions or cutouts S ₅ and S ₆ are located tangentially to these areas 100 and 120 of high density of elementary patterns.

Thus, it becomes much easier to feed the elementary patterns to the pixels which are difficult to access and to which an electrical connection must be linked. It will be noted that the two horizontal separations or cutouts S ₅ and S ₆ are arranged on either side of a line of groups of pixels L ₄ which is intended to form, as will be seen in the following figures, an intermediate horizontal bar for the formation of lowercase letters. Specifically, these separations or cuts S ₅ and S ₆ are arranged tangentially to this line L ₄ and to this intermediate bar.

In addition, this mosaic therefore comprises a third separation or horizontal cut S ₇ which is arranged tangentially to the line L ₃ which forms the group of patterns intended in particular to display an upper horizontal bar of the lower case letters. Preferably, this separation or cut S ₇ is placed directly above the line L ₃ .

As regards henceforth the separation into vertical strips or cuts, it will be specified that at least two of them, namely the separations S ₁ and S ₄ are positioned tangentially to regions or columns C ₁ and C ₅ of the mosaic which are intended in particular to form jambs of letters.

Preferably, the device according to the invention comprises four continuous partitions or cuts which are arranged perpendicular to the direction of reading, these four partitions or cuts respectively defining between them the five columns C ₁ to C ₅ , among which the columns C ₁ , C ₃ and C ₅ respectively constitute lateral and central columns for forming the legs. It will be noted that these central columns C ₃ and lateral columns C ₁ , C ₅ have equal widths. In addition, these three columns C ₁ , C ₃ and C ₅ for forming the legs are separated two by two by intermediate columns C ₂ and C ₄ which are of equal width between them but of a width less than that of the three columns C ₁ , C ₃ and C ₅ .

FIG. 10 represents a chopped weft T ₄ which is the result of the operation of FIG. 9 and to which we will then add isolation spaces Es to form in particular the accents, the jambs or the roundings of certain alphanumeric characters.

As can be seen more precisely in FIG. 6, the mosaic according to the invention comprises four zones for displaying alphanumeric characters of different size.

Indeed, the mosaic according to the invention comprises a first display area A which corresponds to the formation of alphanumeric characters of medium size, and in particular to the formation of a first set of capital letters and numbers (FIGS. 11-18 ). This first zone A uses all the columns and the rows of the mosaic, with the exception of the last L ₆ which corresponds to zone C forming the end of the jamb of the large letters and forming the underscores.

This mosaic comprises a second zone E intended to allow the display of alphanumeric characters of large sizes, namely large capital letters and large numbers. The letters displayed are visible in Figures 19 to 26.

We can see that zone E uses all the available surface of the mosaic, zone A being therefore included in zone E.

The third characteristic display area of this mosaic is area B, which is intended essentially to allow the display of small numbers, in a first position as will be explained below, and lowercase letters. However, lower case letters use part of zone A and part of zone C for certain letterheads and jambs. Thus, this zone B is included in zone A and is placed directly above the underline zone C .

The characters that can be displayed using this area B are shown in Figures 27 to 34.

The mosaic according to the invention further comprises a fourth zone F which in turn allows the display of small figures, but which have a position different from those displayed by zone B, namely significantly higher. Zone F is nested inside zone B which together and in superposition constitute zone A. The characters that can be displayed using this zone F are represented in FIGS. 35 to 38. Thus, it is therefore understood that this mosaic comprises at at least two characteristic zones for the format of characters of the same family (numbers, letters in upper or lower case) but of different sizes. More precisely, it comprises at least two characteristic zones A, B for the formation of figures of different sizes. Even more precisely, it comprises three characteristic zones A, B, E for the formation of figures comprising three different sizes, namely large, medium and small.

Finally, it includes a fourth characteristic zone F for the formation of figures, and in particular small figures, on different levels respectively upper and lower. We therefore understands that very advantageously a mosaic has been provided which is capable of displaying, with the same and unique frame, namely the final hatched frame T5 represented in FIG. 6, different size of figures (small, medium and large) and different sizes d 'the same letter family (large and small). Thus, one can advantageously respond to the problem of predetermined sizing of alphanumeric characters, this possibility of size variation with a single mosaic also making it possible to eliminate a display cell, in the case for example of time display. .

It appears that this device and this method allow the production of an extremely large number of patterns on the same mosaic, which allows styling without constraints the characters while retaining an excellent definition, without affecting the cost price of the device.

It should also be noted that the invention can be applied to an electronic display device with a low multiplexing rate, that is to say in which certain elementary patterns are electrically connected to each other, correspondingly to the multiplexing rate. In this case, the counter-electrode 6b must comprise regions electrically isolated from one another and provided with their own electrical connection, and no longer be one piece (continuous), as is the case for the counter-electrode shown in FIG. 5.

Claims (24)

1. Electronic display device of the type comprising :

   - at least one electro-optical display means (1),

   - elementary patterns (m₁ to m_n) associated with said electro-optical display means (1), such elementary patterns (m₁ to m_n) for the most part conforming to and being based on a series of stylized and selected alpha-numeric characters in the form of a composite mosaic-type structure the grid of which is formed by patterns which exhibit heterogenous and complementary contours arranged so as to nest into one another in a manner similar to that of a puzzle, these elementary patterns forming lines (L1 to L6) and columns (C1 to C5) delimiting characteristic writing zones (A, B) for displaying letters or characters, characterized in that said elementary patterns (m₁ to m_n) are arranged within said writing zones (A, B) in distinct groups (G₁ to G_n) in which said patterns (m₁ to m_n) are arranged together at the limit of joining and are separated by a separation distance (Y) intended to ensure the electric isolation of these patterns from each other, each group of patterns (G₁ to G_n) being separated from the neighbouring group or groups by optically passive separation bands (b₁ , b_n) having a width (X) substantially greater than the separation distance (Y).
2. Device according to claim 1, characterized in that the optically passive bands (b₁ , b_n) exhibit a width (X) at least fifteen times greater than the distance (Y).
3. Device according to claim 1 or 2, characterized in that the width (X) is typically thirty times greater than the distance (Y).
4. Device according to claim 3, characterized in that the distance (Y) is less than 100.10-6 metres.
5. Device according to claim 4, characterized in that the distance (Y) is chosen equal to 50.10^-6 metres.
6. Device according to one of claims 1 to 5, characterized in that said optically passive bands are formed and provided on the mosaic in positions such that such bands are capable of overlapping and masking the elementary patterns of smaller surface in order to eliminate them.
7. Device according to one of claims 1 to 6, characterized in that said bands are rectilinear and all are positioned solely perpendicular or parallel to the reading sense of the characters on the Device.
8. Device according to claim 7, characterized in that it includes at least two separations respectively positioned in a manner tangent to regions of the mosaic intented in particular to form the downstrokes of letters.
9. Device according to claim 7 or 8, characterized in that it includes four continuous separations arranged perpendicular to the reading sense, such four separations defining respectively among themselves five columns, referred to as verticals, three of which respectively constitute the lateral and central columns for forming downstrokes.
10. Device according to claim 9, characterized in that the three vertical columns for forming downstrokes exhibit equal widths.
11. Device according to claim 10, characterized in that the three columns for forming downstrokes are separated two by two by intermediate columns of equal width to one another but of width less than that of said three columns.
12. Device according to one of claims 7 to 11, characterized in that the separations extend over the entire mosaic and open out onto its upper and lower edges.
13. Device according to claim 7, characterized in that it includes at least two separations referred to as horizontals extending parallel to the reading sense of the characters.
14. Device according to claim 13, characterized in that the two horizontal separations are arranged in the neighbourhood of zones in which the density of elementary patterns is greatest.
15. Device according to claim 14, characterized in that said horizontal separations are located in a tangential manner to said greatest density zones.
16. Device according to claim 13, characterized in that the two separations are arranged on either side of an intermediate horizontal bar intended for the forming of lower case letters and in a tangential manner to such bar.
17. Device according to claim 16, characterized in that it includes a third separation arranged in a tangential manner to an upper horizontal lower case bar, directly above the latter.
18. Device according to any one of the preceding claims, characterized in that said mosaic is adapted to display different sizes of characters for a family of letters and/or numbers.
19. Device according to claim 18, characterized in that said mosaic includes at least two characteristic zones (A,E; A,B,E) for forming characters of different sizes within the same family.
20. Device according to claim 18 or 19, characterized in that said mosaic includes at least two characteristic zones (A,B) for forming numbers of different sizes.
21. Device according to claim 20, characterized in that said mosaic includes three characteristic zones (A,B,E) for forming numbers exhibiting three different sizes.
22. Device according to claim 18, characterized in that said mosaic includes a characteristic display zone (F) for forming numbers on respective upper and lower levels within the Device.
23. Device according to claim 18, characterized in that said mosaic includes at least one base grid, referred to as the first grid, which is partially duplicated in order to form display zones for characters of different sizes.
24. Device according to claim 23, characterized in that said first grid is partially duplicated by an additional grid, referred to as the second grid, the second grid being arranged above the first.

Images