EP1112529A1 - Liquid crystal display system and method of operating a liquid crystal display device with visual failure control - Google Patents

Liquid crystal display system and method of operating a liquid crystal display device with visual failure control

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Publication number
EP1112529A1
EP1112529A1 EP99968725A EP99968725A EP1112529A1 EP 1112529 A1 EP1112529 A1 EP 1112529A1 EP 99968725 A EP99968725 A EP 99968725A EP 99968725 A EP99968725 A EP 99968725A EP 1112529 A1 EP1112529 A1 EP 1112529A1
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EP
European Patent Office
Prior art keywords
segments
liquid crystal
crystal display
plate
inverse
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP99968725A
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German (de)
French (fr)
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EP1112529B1 (en
Inventor
Thomas Klemm
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Roche Diagnostics GmbH
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Roche Diagnostics GmbH
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Publication of EP1112529A1 publication Critical patent/EP1112529A1/en
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Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/04—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions
    • G09G3/16—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions by control of light from an independent source
    • G09G3/18—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions by control of light from an independent source using liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/08—Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/12—Test circuits or failure detection circuits included in a display system, as permanent part thereof

Definitions

  • the present invention relates to a liquid crystal display which enables the defective segments to be visually recognized.
  • a first and a second plate are arranged opposite one another, in the space between the first and second plates there is a liquid-crystalline substance.
  • the first plate is transparent to incident light and has essentially transparent, conductive segments for displaying symbols in a display area.
  • the second plate is conductive at least in certain surface areas.
  • This liquid crystal display enables simple visual detection of failed segments. For this purpose, a check is carried out in which all segments and all existing inverse segments are activated, so that when the display is fully functional, a homogeneous picture is obtained or failed segments appear inversely with respect to the rest of the display area.
  • the present invention is in the field of information transfer using liquid crystal displays.
  • liquid crystal displays for the representation of alphanumeric characters or symbols have prevailed, such as. B. in clocks, calculators and the like.
  • a problem that often occurs in practice is that individual segments of the liquid crystal display fail, which is caused by faulty contacts. Circuit breaks, defective driver circuits and the like can be caused. Especially in the medical field, but also in many other areas, failed segments of an LCD display can have fatal consequences. If, for example, the middle crossbar fails in a conventional 7-segment display, an 8 is displayed as 0 and the user or the doctor receives incorrect information. Another critical example is the representation of a decimal point, the absence of which leads to completely wrong results. The task of the It was therefore an object of the present invention to propose a liquid crystal display in which the failure of segments can be easily and reliably recognized by the user.
  • German patent specification 2332970 discloses a 7-segment display which, in addition to the conventional 7 segments, also has one or two diagonally running segments which are used to represent characters. By using these additional segments, it can be ensured that if a segment required for the display fails, a symbol is displayed that the user can recognize as garbled. The display of the sign, which is unusual for the viewer, therefore performs a warning function.
  • the above-mentioned display has the disadvantage that the user has to be careful with every reading. whether the displayed characters are reproduced correctly. With such a display, there is a risk that the user will mentally add a missing segment during quick reading and thus the warning function will be lost.
  • a display is described in US Pat. No. 5,559,528 which has redundant segments.
  • additional segments are provided which run parallel to the conventional segments and thus, if one of the segments fails, the other continues to ensure correct information transmission.
  • such a display has the disadvantage that a large number of individual segments have to be controlled separately, so that both the effort for the electronic control device and for the display itself are greatly increased.
  • Another disadvantage is that with a large number of symbols, the use of redundant segments leads to confusing displays for the user. For example, if a bell, as is known from alarm clocks, is to be displayed, then if redundant segments are used, two such bells would have to be displayed next to one another. H. if the segments work properly, both are displayed. In such a case, the user will be confused as to whether the double display of the alarm bell contains special information.
  • a method for checking liquid crystal displays is also known in the prior art, in which all the segments present are first activated when the display is switched on. The viewer can now visually check whether the 7-segment show the usual shape of an eight, or whether individual segments are missing.
  • this method can only be used for displays in which the user knows the correct appearance of the segments, there is a disadvantage here that a slight inattentiveness of the user is sufficient to overlook any errors in the display.
  • the area occupied by the inverse segment or the areas occupied by the inverse segments should be such that the regular segments are surrounded by the inverse segments. When regular segments and inverse segments are actuated together, this results in a surface which appears homogeneous to the observer, while the failure of a segment makes the observer appear inverse.
  • the present invention discloses a liquid crystal display with which a visual recognition of defective segments is possible in a simple and safe manner.
  • the liquid crystal display has one or more segments which essentially fill the display area which is not covered by the conventional segments and which are referred to as inverse segments in the context of the present invention.
  • the display of a display device according to the invention can be thought of from conventional displays by adding inverse segments.
  • the inverse segments are generally applied or exposed in the same production step as the regular segments (for example in the case of etching processes).
  • the present invention further includes systems in which the liquid crystal displays according to the invention are integrated.
  • the systems have a control device for the liquid crystal display, with which the methods described elsewhere for controlling the display and for displaying characters can be implemented.
  • the systems can advantageously also have a switch or the like with which the control of the display can be initiated, so that it is possible for the user to carry out the control of the display at a point in time chosen by him.
  • a liquid crystal display according to the invention has a first and a second plate which are arranged opposite one another and in the interspace of which there is a liquid crystalline substance. At least one of the two plates is transparent, so that the user can perceive a change in the optical properties of the liquid-crystalline substance through this plate.
  • the basic structure of liquid crystal displays is known in the prior art, so that in this application a more detailed description is given only for the details essential in connection with the invention.
  • a detailed compilation of suitable liquid crystalline substances as well as the structure and functioning of liquid crystal displays can be found in Ullmann's encyclopedia of technical chemistry under the keyword "liquid crystals " * .
  • the present invention is applicable to both liquid crystal displays which operate in transmission and in reflection. Accordingly, one of the plates mentioned is transparent and the other plate can either be transparent or reflective. Furthermore, the invention is not limited to a special display system, but can generally be used for systems in which an optically perceptible change in the liquid-crystalline substance is caused by an electric field.
  • Ullmann's encyclopedia of chemical engineering for example, describes the principle of dynamic scattering, the principle of deformation of aligned phases and display systems based on the so-called Schadt-Helfrich effect. The latter principle in particular can be used well in a large number of cases and is distinguished by its long operating times and low power consumption.
  • the liquid-crystalline substance is located between crossed polarizers and the layer thickness of the liquid-crystalline substance is selected so that the light experiences a phase rotation of 90 °. Without one Controlling the display, such a display therefore appears transparent.
  • an electrical voltage of approx. 1 to 5 volts the liquid crystalline phase is reoriented and the display appears opaque in the areas in which the reorientation takes place.
  • An electric field is generally used to control liquid crystal displays.
  • transparent conductive layers are applied to the plates, between which the liquid crystalline substance is located.
  • the conductive layer provided in front of the reflective layer can optionally be made opaque and reflective.
  • Transparent conductive layers can be produced by vapor deposition or detection, tin (IV) oxide layers doped with antimony or indium (I ⁇ I) oxide layers doped with tin (IV) oxide.
  • the guide layers are given the shape of segments to display characters with the liquid crystal display.
  • the term “segments ” is used in the context of the present invention both for the individual segments of conventional segment displays and for symbols, such as alarm bells, arrows, stylized thermometers and the like.
  • the segments are connected via leads to contacts in the edge area of the plate on which the segments are located.
  • the electrical leads are also made of transparent conductive layers. If the conductive layer is carried out continuously on the opposite plate, the electrical supply lines also appear on the display when the respective segments are activated. However, this is undesirable, so that the counter electrode on the second plate is usually carried out in such a way that a substantial electric field is only built up between the segments to be displayed and the counter electrode, but not between the leads and the counter electrode.
  • FIG. 1 shows a liquid crystal display of the prior art.
  • 1A shows the electrodes which are applied to a plate of a liquid crystal display. Both the segments (1), their feed lines (2) and the contacts (3) are shown in the figure.
  • FIG. 1B shows a counterelectrode which is arranged such that the conductor tracks which can be recognized as eight come to lie in the display in relation to the corresponding eighths of FIG. Since there are no counter electrodes in the area of the leads and contacts, they do not appear in the liquid crystal display, even if they are on a tial opposite the counter electrode.
  • the counter electrode can also be constructed from individually controllable segments. In this way it can be achieved that an electric field can be limited to the desired area of the display. For multiplex displays, a counter electrode with a higher number of supply lines is required, however, supply lines can be saved for the actual electrode, so that a smaller number of supply lines results overall.
  • FIG. 2 shows the segments which are applied to one of the plates of the liquid crystal display.
  • Both the conventional segments A to G and the inverse segments (10) according to the invention are present in this 7-segment display.
  • the inverse segments fill the display area in the area. in which there are no regular segments or feed lines. There must be no electrical contact between the inverse segments and the regular segments and their supply lines, so that the inverse segments can be controlled independently of the other segments, so the inverse segments do not completely fill the display area, but spaces remain that prevent an electrical short circuit.
  • the distance between the segments or between the segments and the inverse segments is in the range of approx. 50-100 ⁇ m. It is also possible to provide the inverse segment (s) only in part of the display area.
  • the result of the inverse segments is that, in the case of a failed, regular segment, the viewer can recognize the failed segment as missing due to the frame specified by the inverse segment. It is therefore not necessary for the inverse segments to completely fill the area uncovered by the regular segments. It is more important that the inverse segments form a coherent surface together with the regular segments. A defective segment can be identified as missing in this area when all segments are activated.
  • FIG. 3 shows a segment arrangement according to the invention for representing a zero.
  • an inverse segment which essentially comprises the interior and the surrounding area of the zero.
  • the counter electrode can consist of a conductive surface of essentially the same size.
  • the segments and inverse segments of the counterelectrode are essentially congruent, with the exception that the respective leads to the segments are in different areas, so that the leads are not visible in the display when segments are activated.
  • a functional check of the liquid crystal display can be carried out according to the following procedure:
  • the display device is designed so that it appears uniformly bright without activation.
  • a Schadt-Helfrich display with crossed polarizers is preferably used for this.
  • the liquid-crystalline substance is selected so that it causes an optical rotation of 90 ° or 270 ° without applied voltage.
  • both the segments and the inverse segments are activated, so that the display appears dark to the viewer.
  • the display is homogeneously dark.
  • one of the segments should have failed, there is no potential difference between this segment and the counterelectrode and the area of the segment appears as bright. Due to the inverse segments, it is possible for the viewer to see what shape the failed segment has, since a bright one Gap remains on the otherwise dark display.
  • the functional segments and inverse segments form a frame, so to speak, against which a failed segment is highlighted inversely.
  • a device with such a display can accordingly control all segments and inverse segments for a few seconds when switching on or when actuated by the user, as mentioned above, in order to give the viewer the possibility of recognizing defective segments.
  • the segments of the display can be controlled as for commercial displays, ie control of the inverse segments is only necessary if the display is to be checked again.
  • Such a display has the advantage that the electronic circuits and control algorithms are only slightly compared to conventional displays. O
  • the reverse procedure is also possible; H. an advertisement is designed in such a way that it appears homogeneously dark to the viewer when it is switched off. This can be achieved, for example, with a Schadt-Helfrich display in which the polarizers are aligned in the same direction.
  • a Schadt-Helfrich display in which the polarizers are aligned in the same direction.
  • all segments and inverse segments are first activated according to the invention. If there are now defective segments, they stand out darkly from the otherwise bright display.
  • the actual display of information to be displayed can now take place in two ways:
  • the segments to be displayed are activated so that they appear bright compared to the otherwise dark display.
  • the controlled segments form translucent areas. If backlighting of the display device is provided, the controlled segments appear to the viewer to be illuminated.
  • This operating mode can be used advantageously for displays that are read in the dark, such as. B. speedometer, car radios. Clinical thermometer etc.
  • the display is activated inversely to the usual activation, i. H. all segments that should not be shown, as well as the inverse segments. are activated while the segments to be displayed are not activated and accordingly remain dark.
  • control devices known in the prior art for conventional liquid crystal displays can be used to drive a liquid crystal display according to the invention.
  • the control devices it is only necessary to additionally provide one or more electrical outputs for the inverse segments, by means of which these can be controlled selectively (i.e. separately from the regular segments).
  • Electronic control components for liquid crystal displays are, for example, in the data book “Philips Components”, (1989) published in Dr. Alfred Wilsonhing Verlag GmbH (see e.g. PCF 8576).

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Liquid Crystal (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

The invention relates to liquid crystal display with conductive segments for representing symbols, which also have at least one inverse segment that fills at least in part the display area not covered by the remaining segments. This liquid crystal display makes it possible to simply and visually detected faulty segments. To this end, a control is carried out wherein all segments and all existing inverse segments are activated so that a homogenous image is viewed when the display is completely functional or the faulty segments are inversely displayed in relation to the remaining display surfaces.

Description

LCD-Display mit AusfallkontrolleLCD display with failure control
Die vorliegende Erfindung betrifft eine Flüssigkristallanzeige, die ein visuelles Erkennen fehlerhafter Segmente ermöglicht. Bei der Anzeige sind eine erste und eine zweite Platte gegenüberliegend angeordnet, im Zwischenraum zwischen erster und zweiter Platte befindet sich eine flüssigkristalline Substanz. Die erste Platte ist transparent für einfallendes Licht und weist in einem Anzeigebereich im wesentlichen transparente, leitfähige Segmente zur Darstellung von Symbolen auf. Die zweite Platte ist zumindest in bestimmten Flächenbereichen leitfähig ist. Erfindungsgemäß ist auf der ersten Platte weiterhin mindestens ein leitfähiges Inverssegment vorhanden, das die nicht von den Segmenten zur Darstellung von Symbolen bedeckte Anzeigefläche zumindest zum Teil ausfüllt. Mit dieser Flüssigkristallanzeige ist eine einfache visuelle Erkennung ausgefallener Segmente möglich. Hierzu wird eine Kontrolle durchgeführt, bei der alle Segmente sowie alle vorhandenen Inverssegmente angesteuert werden, so daß sich bei vollständig funktionsfähiger Anzeige ein homogenes Bild ergibt bzw. ausgefallene Segmente gegenüber der restlichen Anzeigefläche invers erscheinen.The present invention relates to a liquid crystal display which enables the defective segments to be visually recognized. In the display, a first and a second plate are arranged opposite one another, in the space between the first and second plates there is a liquid-crystalline substance. The first plate is transparent to incident light and has essentially transparent, conductive segments for displaying symbols in a display area. The second plate is conductive at least in certain surface areas. According to the invention, there is also at least one conductive inverse segment on the first plate, which at least partially fills the display area not covered by the segments for representing symbols. This liquid crystal display enables simple visual detection of failed segments. For this purpose, a check is carried out in which all segments and all existing inverse segments are activated, so that when the display is fully functional, a homogeneous picture is obtained or failed segments appear inversely with respect to the rest of the display area.
Die vorliegende Erfindung fällt in das Gebiet der Informationsübermittlung mittels Flüssigkristallanzeigen. In vielen Bereichen haben sich Flüssigkristallanzeigen zur Darstellung von alphanumerischen Zeichen oder Symbolen durchgesetzt, wie z. B. bei Uhren, Taschenrechnern und dergleichen. Ein in der Praxis jedoch häufig auftretendes Problem liegt darin, daß einzelne Segmente der Flüssigkristallanzeige ausfallen, was durch fehlerhafte Kontakte. Leiterbahnunterbrechungen, defekte Treiberschaltungen und dergleichen verursacht sein kann. Insbesondere im medizinischen Bereich, jedoch auch in vielen anderen Bereichen, können ausgefallene Segmente eines LCD-Displays fatale Folgen haben. Fällt beispielsweise bei einer herkömmlichen 7-Segmentdarstellung der mittlere Querbalken aus« so wird eine 8 als 0 dargestellt und der Benutzer oder der Arzt erhält eine fehlerhafte Information. Als weiteres kritisches Beispiel ist die Darstellung eines Dezimalpunktes zu nennen, dessen Fehlen zu vollkommen falschen Resultaten führt. Die Aufgabe der vor- liegenden Erfindung war es daher, eine Flüssigkristallanzeige vorzuschlagen, bei der vom Benutzer der Ausfall von Segmenten einfach und sicher erkannt werden kann.The present invention is in the field of information transfer using liquid crystal displays. In many areas, liquid crystal displays for the representation of alphanumeric characters or symbols have prevailed, such as. B. in clocks, calculators and the like. A problem that often occurs in practice is that individual segments of the liquid crystal display fail, which is caused by faulty contacts. Circuit breaks, defective driver circuits and the like can be caused. Especially in the medical field, but also in many other areas, failed segments of an LCD display can have fatal consequences. If, for example, the middle crossbar fails in a conventional 7-segment display, an 8 is displayed as 0 and the user or the doctor receives incorrect information. Another critical example is the representation of a decimal point, the absence of which leads to completely wrong results. The task of the It was therefore an object of the present invention to propose a liquid crystal display in which the failure of segments can be easily and reliably recognized by the user.
Im Stand der Technik sind bereits Verfahren bekannt, die eine fehlerhafte Informationsübermittlung infolge ausgefallener Segmente vermeiden helfen. In der deutschen Patentschrift 2332970 wird eine 7-Segmentanzeige offenbart, die außer den herkömmlichen 7 Segmenten noch ein bis zwei diagonal verlaufende Segmente besitzt, die zur Darstellung von Zeichen verwendet werden. Durch den Einsatz dieser zusätzlichen Segmente kann sichergestellt werden, daß bei Ausfall eines zur Darstellung benötigten Segmentes ein Symbol angezeigt wird, daß vom Benutzer als verstümmelt erkannt werden kann. Die für den Betrachter ungewohnte Darstellung des Zeichens übt demnach eine Warnfunktion aus. Die genannte Anzeige besitzt jedoch den Nachteil, daß der Benutzer bei jeder Ablesung aufpassen muß. ob die dargestellten Zeichen korrekt wiedergegeben sind. Bei einer derartigen Anzeige besteht die Gefahr, daß der Benutzer ein fehlendes Segment bei schneller Ablesung gedanklich ergänzt und somit die Warnfunktion verlorengeht.Methods are already known in the prior art which help to avoid incorrect information transmission as a result of failed segments. German patent specification 2332970 discloses a 7-segment display which, in addition to the conventional 7 segments, also has one or two diagonally running segments which are used to represent characters. By using these additional segments, it can be ensured that if a segment required for the display fails, a symbol is displayed that the user can recognize as garbled. The display of the sign, which is unusual for the viewer, therefore performs a warning function. However, the above-mentioned display has the disadvantage that the user has to be careful with every reading. whether the displayed characters are reproduced correctly. With such a display, there is a risk that the user will mentally add a missing segment during quick reading and thus the warning function will be lost.
In der US-5,559,528 ist ein Display beschrieben, das redundante Segmente aufweist. Bei diesem Display sind zusätzliche Segmente vorgesehen, die parallel zu den herkömmlichen Segmenten verlaufen und somit bei Ausfall eines der Segmente das andere weiterhin für eine korrekte Informationsübermittlung sorgt. Ein derartiges Display hat jedoch den Nachteil, daß eine Vielzahl von Einzelsegmenten separat angesteuert werden muß, so daß sich sowohl der Aufwand für die elektronische Ansteuerungsvorrichtung als auch für das Display selbst stark erhöht. Ein weiterer Nachteil besteht darin, daß bei einer Vielzahl von Symbolen eine Verwendung redundanter Segmente für den Benutzer zu verwirrenden Anzeigen führt. Soll beispielsweise eine Glocke, wie von Alarmweckern bekannt, dargestellt werden, so müßten bei Verwendung redundanter Segmente zwei derartige Glocken nebeneinander dargestellt werden, die auch im Normalfall, d. h. wenn die Segmente einwandfrei funktionieren, beide angezeigt werden. Der Benutzer wird in einem solchen Fall irritiert sein, ob die doppelte Anzeige der Alarmglocke eine besondere Information birgt.A display is described in US Pat. No. 5,559,528 which has redundant segments. In this display, additional segments are provided which run parallel to the conventional segments and thus, if one of the segments fails, the other continues to ensure correct information transmission. However, such a display has the disadvantage that a large number of individual segments have to be controlled separately, so that both the effort for the electronic control device and for the display itself are greatly increased. Another disadvantage is that with a large number of symbols, the use of redundant segments leads to confusing displays for the user. For example, if a bell, as is known from alarm clocks, is to be displayed, then if redundant segments are used, two such bells would have to be displayed next to one another. H. if the segments work properly, both are displayed. In such a case, the user will be confused as to whether the double display of the alarm bell contains special information.
Im Stand der Technik ist weiterhin ein Verfahren zur Kontrolle von Flüssigkristallanzeigen bekannt, bei dem beim Einschalten der Anzeige zunächst alle vorhandenen Segmente aktiviert werden. Der Betrachter kann nunmehr visuell kontrollieren, ob die 7-Segmentan- zeigen die gewohnte Form einer Acht darstellen, oder ob einzelne Segmente fehlen. Neben dem Nachteil, daß dieses Verfahren nur auf Anzeigen angewandt werden kann, bei denen dem Benutzer das korrekte Erscheinungsbild der Segmente bekannt ist, besteht hier ein Nachteil darin, daß eine leichte Unaufmerksamkeit des Benutzers ausreicht, um etwaige Fehler der Anzeige zu übersehen.A method for checking liquid crystal displays is also known in the prior art, in which all the segments present are first activated when the display is switched on. The viewer can now visually check whether the 7-segment show the usual shape of an eight, or whether individual segments are missing. In addition to the disadvantage that this method can only be used for displays in which the user knows the correct appearance of the segments, there is a disadvantage here that a slight inattentiveness of the user is sufficient to overlook any errors in the display.
In der deutschen Offenlegungsschrift DE 37 04 031 wird eine Flüssigkristallanzeige beschrieben, die Kontrollsegmente aufweist, die mit den regulären Anzeigesegmenten elektrisch in Reihe geschaltet sind. Weiterhin werden Ergänzungssegmente beschrieben, die neben den Kontrollsegmenten liegen um zusammen mit diesen ein augenfälliges Symbol zu bilden. Mit dieser Anordnung ist es möglich zu überprüfen, ob die Versorgung eines Kontrollsystems und des mit ihm verbundenen regulären Segmentes intakt ist. Eine Unterbrechung der Leiterstrecke zwischen dem Kontrollsymbol und dem zugeordneten regulären Segment ist mit dieser Anordnung jedoch nicht möglich.In the German patent application DE 37 04 031 a liquid crystal display is described which has control segments which are electrically connected in series with the regular display segments. Furthermore, supplementary segments are described which lie next to the control segments in order to form an eye-catching symbol with them. With this arrangement it is possible to check whether the supply of a control system and the regular segment connected to it is intact. However, an interruption of the conductor route between the control symbol and the assigned regular segment is not possible with this arrangement.
Der von Inverssegment eingenommene Bereich bzw. die von den Inverssegmenten eingenommenen Bereiche sollten dergestalt sein, daß die regulären Segmente von den Inverssegmenten umgeben sind. Bei gemeinsamer Ansteuerung von regulären Segmenten und Inverssegmenten ergibt sich so eine dem Betrachter homogen erscheinende Fläche, während der Ausfall eines Sgementes dieses dem Betrachter invers erscheinen läßt.The area occupied by the inverse segment or the areas occupied by the inverse segments should be such that the regular segments are surrounded by the inverse segments. When regular segments and inverse segments are actuated together, this results in a surface which appears homogeneous to the observer, while the failure of a segment makes the observer appear inverse.
Es ist weiterhin möglich, daß das bzw. die Inverssegment* e) nur in einem Teil der Anzeigefläche vorzusehen, in dem das Erkennen eines Segmentausfalles besonders wichtig ist.It is also possible to provide the inverse segment (s) * e) only in a part of the display area in which the detection of a segment failure is particularly important.
Die vorliegende Erfindung offenbart eine Flüssigkristallanzeige, mit der ein visuelles Erkennen fehlerhafter Segmente auf einfache und sichere Weise möglich ist. Hierzu besitzt die Flüssigkristallanzeige neben den herkömmlichen Segmenten zur Darstellung alphanumerischer Zeichen oder von Symbolen ein oder mehrere Segmente, die die nicht von den herkömmlichen Segmenten bedeckte Anzeigefläche im wesentlichen ausfüllen, und die im Rahmen der vorliegenden Erfindung als Inverssegmente bezeichnet werden. Somit kann das Display einer erfindungsgemäßen Anzeigevorrichtung aus konventionellen Displays durch Hinzufügung von Inverssegmenten gedacht werden. Bei der Herstellung erfindungsgemäßer Displays werden die Inverssegmente in der Regel jedoch im gleichen Herstellschritt wie die regulären Segmente aufgebracht bzw. freigelegt (z. B. bei Ätzprozessen). Die vorliegende Erfindung umfaßt weiterhin Systeme, in die die erfindungsgemäße Flüssigkristallanzeigen integriert sind. Die Systeme besitzen eine Ansteuervorrichtung für die Flüssigkristallanzeige, mit der die an anderer Stelle beschriebenen Verfahren zur Kontrolle der Anzeige und zur Darstellung von Zeichen implementiert werden können. Vorteilhaft können die Systeme auch einen Schalter oder dergleichen besitzen, mit dem die Kontrolle der Anzeige eingeleitet werden kann, so daß es dem Benutzer möglich ist, die Kontrolle der Anzeige zu einem von ihm gewählten Zeitpunkt durchzuführen.The present invention discloses a liquid crystal display with which a visual recognition of defective segments is possible in a simple and safe manner. For this purpose, in addition to the conventional segments for representing alphanumeric characters or symbols, the liquid crystal display has one or more segments which essentially fill the display area which is not covered by the conventional segments and which are referred to as inverse segments in the context of the present invention. Thus, the display of a display device according to the invention can be thought of from conventional displays by adding inverse segments. When manufacturing displays according to the invention, however, the inverse segments are generally applied or exposed in the same production step as the regular segments (for example in the case of etching processes). The present invention further includes systems in which the liquid crystal displays according to the invention are integrated. The systems have a control device for the liquid crystal display, with which the methods described elsewhere for controlling the display and for displaying characters can be implemented. The systems can advantageously also have a switch or the like with which the control of the display can be initiated, so that it is possible for the user to carry out the control of the display at a point in time chosen by him.
Eine erfindungsgemäße Flüssigkristallanzeige besitzt eine erste und eine zweite Platte, die gegenüberliegend angeordnet sind, und in deren Zwischenraum sich eine flüssigkristalline Substanz befindet. Mindestens eine der beiden Platten ist transparent, so daß der Benutzer durch diese Platte eine Veränderung der optischen Eigenschaften der flüssigkristallinen Substanz wahrnehmen kann. Der prinzipielle Aufbau von Flüssigkristallanzeigen ist im Stand der Technik bekannt, so daß in dieser Anmeldung lediglich für die im Zusammenhang mit der Erfindung wesentlichen Details eine nähere Beschreibung erfolgt. Eine detaillierte Zusammenstellung geeigneter flüssigkristalliner Substanzen sowie dem Aufbau und der Funktionsweise von Flüssigkristallanzeigen findet sich in Ullmanns Enzyklopädie der Technischen Chemie unter dem Stichwort "Flüssigkristalle"*.A liquid crystal display according to the invention has a first and a second plate which are arranged opposite one another and in the interspace of which there is a liquid crystalline substance. At least one of the two plates is transparent, so that the user can perceive a change in the optical properties of the liquid-crystalline substance through this plate. The basic structure of liquid crystal displays is known in the prior art, so that in this application a more detailed description is given only for the details essential in connection with the invention. A detailed compilation of suitable liquid crystalline substances as well as the structure and functioning of liquid crystal displays can be found in Ullmann's encyclopedia of technical chemistry under the keyword "liquid crystals " * .
Die vorliegende Erfindung ist sowohl auf Flüssigkristallanzeigen anwendbar, die in Transmission als auch in Reflektion arbeiten. Dementsprechend ist eine der genannten Platten transparent und die andere Platte kann entweder transparent oder reflektierend gestaltet sein. Weiterhin ist die Erfindung nicht auf ein spezielles Anzeigesystem beschränkt, sondern kann generell für solche Systeme eingesetzt werden, bei denen eine optisch wahrnehmbare Veränderung der flüssigkristallinen Substanz durch ein elektrisches Feld hervorgerufen wird. In Ullmanns Enzyklopädie der Technischen Chemie werden beispielsweise das Prinzip der dynamischen Streuung, das Prinzip der Deformation ausgerichteter Phasen sowie Anzeigesysteme nach dem sogenannten Schadt-Helfrich-Effekt beschrieben. Insbesondere das letztgenannte Prinzip ist in einer Vielzahl von Fällen gut anwendbar und zeichnet sich durch seine langen Betriebszeiten sowie die geringe Leistungsaufnahme aus. Bei Anzeigesystemen nach dem Schadt-Helfrich-Effekt befindet sich die flüssigkristalline Substanz zwischen gekreuzten Polarisatoren und die Schichtdicke der flüssigkristallinen Substanz wird so gewählt, daß das Licht eine Phasendrehung von 90 ° erfährt. Ohne eine Ansteuerung der Anzeige erscheint eine derartige Anzeige daher transparent. Durch Anlegen einer elektrischen Spannung von ca. 1 bis 5 Volt wird die flüssigkristalline Phase umorientiert und die Anzeige erscheint in den Bereichen, in denen die Umorientierung erfolgt, als lichtundurchlässig.The present invention is applicable to both liquid crystal displays which operate in transmission and in reflection. Accordingly, one of the plates mentioned is transparent and the other plate can either be transparent or reflective. Furthermore, the invention is not limited to a special display system, but can generally be used for systems in which an optically perceptible change in the liquid-crystalline substance is caused by an electric field. Ullmann's encyclopedia of chemical engineering, for example, describes the principle of dynamic scattering, the principle of deformation of aligned phases and display systems based on the so-called Schadt-Helfrich effect. The latter principle in particular can be used well in a large number of cases and is distinguished by its long operating times and low power consumption. In display systems based on the Schadt-Helfrich effect, the liquid-crystalline substance is located between crossed polarizers and the layer thickness of the liquid-crystalline substance is selected so that the light experiences a phase rotation of 90 °. Without one Controlling the display, such a display therefore appears transparent. By applying an electrical voltage of approx. 1 to 5 volts, the liquid crystalline phase is reoriented and the display appears opaque in the areas in which the reorientation takes place.
Zur Ansteuerung flüssigkristalliner Anzeigen wird generell ein elektrisches Feld verwendet. Hierzu werden transparente Leitschichten auf die Platten, zwischen denen sich die flüssigkristalline Substanz befindet, aufgebracht. Bei einer reflektierenden Anzeige kann die vor der reflektierenden Schicht angebrachte Leitschicht gegebenenfalls lichtundurchlässig und reflektierend ausgebildet sein. Transparente Leitschichten können durch Aufdampfen oder Aufspürten, von mit Antimon dotierten Zinn (IV) Oxidschichten oder mit Zinn (IV) Oxid dotierte Indium (IΙI)-Oxidschichten erzeugt werden.An electric field is generally used to control liquid crystal displays. For this purpose, transparent conductive layers are applied to the plates, between which the liquid crystalline substance is located. In the case of a reflective display, the conductive layer provided in front of the reflective layer can optionally be made opaque and reflective. Transparent conductive layers can be produced by vapor deposition or detection, tin (IV) oxide layers doped with antimony or indium (IΙI) oxide layers doped with tin (IV) oxide.
Zur Darstellung von Zeichen mit der Flüssigkristallanzeige wird den Leitschichten die Form von Segmenten verliehen. Der Begriff "Segmente" wird im Rahmen der vorliegenden Erfindung sowohl für die Einzelsegmente herkömmlicher Segmentanzeigen als auch für Symbole, wie beispielsweise Alarmglocken, Pfeile, stilisierte Thermometer und dergleichen, verwendet. Die Segmente sind über Zuleitungen mit Kontakten im Randbereich der Platte verbunden, auf denen sich die Segmente befinden. Die elektrischen Zuleitungen werden ebenfalls aus transparenten Leitschichten hergestellt. Wird die leitfähige Schicht auf der gegenüberliegenden Platte durchgängig ausgeführt, so erscheinen die elektrischen Zuleitungen beim Ansteuern der jeweiligen Segmente ebenfalls auf der Anzeige. Dies ist jedoch unerwünscht, so daß die Gegenelektrode auf der zweiten Platte im Regelfall so ausgeführt wird, daß nur zwischen den darzustellenden Segmenten und der Gegenelektrode ein substantielles elektrisches Feld aufgebaut wird, nicht jedoch zwischen den Zuleitungen und der Gegenelektrode. Dieses ist in der Figur 1 näher dargestellt, die eine Flüssigkristallanzeige des Standes der Technik zeigt. In Figur 1 A sind die Elektroden dargestellt, die auf einer Platte einer Flüssigkristallanzeige aufgebracht sind. In der Figur sind sowohl die Segmente (1), deren Zuleitungen (2) und die Kontakte (3) dargestellt. In Figur 1B ist eine Gegenelektrode dargestellt, die so angeordnet wird, daß die als Acht erkennbaren Leiterbahnen in der Anzeige gegenüber den entsprechenden Achten der Figur 1 A zu liegen kommen. Da sich im Bereich der Zuleitungen und Kontakte keine Gegenelektroden befinden, erscheinen diese nicht in der Flüssigkristallanzeige, selbst wenn sie auf einem Poten- tial gegenüber der Gegenelektrode liegen. Bei sogenannten Multiplex-Anzeigen kann die Gegenelektrode auch aus einzeln ansteuerbaren Segmenten aufgebaut sein. Hierdurch kann erreicht werden, daß ein elektrisches Feld auf den gewünschten Bereich der Anzeige beschränkt werden kann. Für Multiplex-Anzeigen wird eine Gegenelektrode mit einer höheren Zahl von Zuleitungen benötigt, jedoch können dafür bei der eigentlichen Elektrode Zuleitungen eingespart werden, so daß sich insgesamt eine geringere Zahl von Zuleitungen ergibt.The guide layers are given the shape of segments to display characters with the liquid crystal display. The term “segments ” is used in the context of the present invention both for the individual segments of conventional segment displays and for symbols, such as alarm bells, arrows, stylized thermometers and the like. The segments are connected via leads to contacts in the edge area of the plate on which the segments are located. The electrical leads are also made of transparent conductive layers. If the conductive layer is carried out continuously on the opposite plate, the electrical supply lines also appear on the display when the respective segments are activated. However, this is undesirable, so that the counter electrode on the second plate is usually carried out in such a way that a substantial electric field is only built up between the segments to be displayed and the counter electrode, but not between the leads and the counter electrode. This is shown in more detail in FIG. 1, which shows a liquid crystal display of the prior art. 1A shows the electrodes which are applied to a plate of a liquid crystal display. Both the segments (1), their feed lines (2) and the contacts (3) are shown in the figure. FIG. 1B shows a counterelectrode which is arranged such that the conductor tracks which can be recognized as eight come to lie in the display in relation to the corresponding eighths of FIG. Since there are no counter electrodes in the area of the leads and contacts, they do not appear in the liquid crystal display, even if they are on a tial opposite the counter electrode. In so-called multiplex displays, the counter electrode can also be constructed from individually controllable segments. In this way it can be achieved that an electric field can be limited to the desired area of the display. For multiplex displays, a counter electrode with a higher number of supply lines is required, however, supply lines can be saved for the actual electrode, so that a smaller number of supply lines results overall.
Die Funktionsweise der vorliegenden Erfindung wird anhand der Figur 2 erläutert:The mode of operation of the present invention is explained with reference to FIG. 2:
Figur 2 zeigt die Segmente, die auf einer der Platten der Flüssigkristallanzeige aufgebracht sind. Es sind bei dieser 7-Segmentanzeige sowohl die herkömmlichen Segmente A bis G vorhanden, als auch erfindungsgemäße Inverssegmente (10). Die Inverssegmente füllen die Anzeigefläche in dem Bereich aus. in dem keine regulären Segmente oder Zuleitungen vorhanden sind. Zwischen den Inverssegmenten und den regulären Segmenten sowie deren Zuleitungen darf kein elektrischer Kontakt bestehen, damit die Inverssegmente unabhängig von den übrigen Segmenten angesteuert werden können, daher füllen die Inverssegmente die Anzeigefläche nicht vollständig aus, sondern es verbleiben Zwischenräume, die einen elektrischen Kurzschluß verhindern. Der Abstand zwischen den Segmenten bzw. zwischen den Segmenten und den Inverssegmenten liegt im Bereich von ca. 50 - 100 μm. Es ist auch möglich das bzw. die Inverssegmente nur in einem Teil der Anzeigefläche vorzusehen.FIG. 2 shows the segments which are applied to one of the plates of the liquid crystal display. Both the conventional segments A to G and the inverse segments (10) according to the invention are present in this 7-segment display. The inverse segments fill the display area in the area. in which there are no regular segments or feed lines. There must be no electrical contact between the inverse segments and the regular segments and their supply lines, so that the inverse segments can be controlled independently of the other segments, so the inverse segments do not completely fill the display area, but spaces remain that prevent an electrical short circuit. The distance between the segments or between the segments and the inverse segments is in the range of approx. 50-100 μm. It is also possible to provide the inverse segment (s) only in part of the display area.
Durch die Inverssegmente wird erreicht, daß der Betrachter bei einem ausgefallenen, regulären Segment durch den durch das Inverssegment vorgegebenen Rahmen das ausgefallene Segment als fehlend erkennen kann. Somit ist es nicht notwendig, daß die Inverssegmente die von den regulären Segmenten unbedeckte Fläche vollständig ausfüllen. Vielmehr kommt es darauf an, daß die Inverssegmente zusammen mit den regulären Segmenten optisch wahrnehmbar eine zusammenhängende Fläche bilden. Ein defektes Segment kann so bei Ansteuerung aller Segmente als in dieser Fläche fehlend erkannt werden.The result of the inverse segments is that, in the case of a failed, regular segment, the viewer can recognize the failed segment as missing due to the frame specified by the inverse segment. It is therefore not necessary for the inverse segments to completely fill the area uncovered by the regular segments. It is more important that the inverse segments form a coherent surface together with the regular segments. A defective segment can be identified as missing in this area when all segments are activated.
In der Figur 3 ist eine erfindungsgemäße Segmentanordnung zur Darstellung einer Null gezeigt. Neben einem Segment zur Darstellung der Null gibt es ein Inverssegment, das im wesentlichen den Innenraum sowie den Umgebungsbereich der Null umfaßt. Für die in den Figuren 2 und 3 gezeigten Elektroden kann die Gegenelektrode aus einer leitfähigen Fläche im wesentlichen gleicher Größe bestehen. Vorteilhaft sind die Segmente und Inverssegmente der Gegenelektrode im wesentlichen kongruent aufgebaut, mit der Ausnahme, daß die jeweiligen Zuleitungen zu den Segmenten in verschiedenen Bereichen liegen, so daß die Zuleitungen bei der Aktivierung von Segmenten in der Anzeige nicht sichtbar werden.FIG. 3 shows a segment arrangement according to the invention for representing a zero. In addition to a segment to represent the zero, there is an inverse segment which essentially comprises the interior and the surrounding area of the zero. For the electrodes shown in FIGS. 2 and 3, the counter electrode can consist of a conductive surface of essentially the same size. Advantageously, the segments and inverse segments of the counterelectrode are essentially congruent, with the exception that the respective leads to the segments are in different areas, so that the leads are not visible in the display when segments are activated.
Eine Funktionskontrolle der Flüssigkristallanzeige kann nach folgendem Verfahren ablaufen:A functional check of the liquid crystal display can be carried out according to the following procedure:
Die Anzeigevorrichtung wird so ausgelegt, daß sie ohne Ansteuerung einheitlich hell erscheint. Im Rahmen der vorliegenden Erfindung wird hierzu bevorzugt eine Schadt- Helfrich-Anzeige mit gekreuzten Polarisatoren eingesetzt. Hierbei wird die flüssigkristalline Substanz so gewählt, daß sie ohne angelegte Spannung eine optische Drehung von 90 ° oder 270 ° hervorruft.The display device is designed so that it appears uniformly bright without activation. In the context of the present invention, a Schadt-Helfrich display with crossed polarizers is preferably used for this. Here, the liquid-crystalline substance is selected so that it causes an optical rotation of 90 ° or 270 ° without applied voltage.
Zur Kontrolle der Anzeige werden sowohl die Segmente als auch die Inverssegmente angesteuert, so daß die Anzeige dem Betrachter dunkel erscheint. Bei Funktionsweise aller Segmente ist die Anzeige homogen dunkel. Sollte jedoch eines der Segmente ausgefallen sein, so besteht zwischen diesem Segment und der Gegenelektrode keine Potentialdifferenz und der Bereich des Segmentes erschient als hell. Bedingt durch die Inverssegmente ist es für den Betrachter möglich zu erkennen, welche Form das ausgefallene Segment aufweist, da ein heller Zwischenraum auf der ansonsten dunklen Anzeige verbleibt. Die funktionsfähigen Segmente und Inverssegmente bilden sozusagen einen Rahmen, gegenüber dem sich ein ausgefallenes Segment invers hervorhebt. Ein Gerät mit einer derartigen Anzeige kann zur Kontrolle der Anzeige dementsprechend beim Einschalten oder bei Betätigung durch den Benutzer wie vorstehend genannt eine Ansteuerung aller Segmente und Inverssegmente für wenige Sekunden durchführen, um dem Betrachter die Möglichkeit zur Erkennung fehlerhafter Segmente zu geben. Nach dieser Kontrolle können die Segmente der Anzeige wie für handelsübliche Anzeigen angesteuert werden, d. h. eine Ansteuerung der Inverssegmente ist nur notwendig, wenn eine erneute Kontrolle der Anzeige durchgeführt werden soll. Eine derartige Anzeige hat den Vorteil, daß die elektronischen Schaltungen und Ansteueralgorithmen gegenüber konventionellen Anzeigen nur gering- oTo control the display, both the segments and the inverse segments are activated, so that the display appears dark to the viewer. When all segments work, the display is homogeneously dark. However, if one of the segments should have failed, there is no potential difference between this segment and the counterelectrode and the area of the segment appears as bright. Due to the inverse segments, it is possible for the viewer to see what shape the failed segment has, since a bright one Gap remains on the otherwise dark display. The functional segments and inverse segments form a frame, so to speak, against which a failed segment is highlighted inversely. A device with such a display can accordingly control all segments and inverse segments for a few seconds when switching on or when actuated by the user, as mentioned above, in order to give the viewer the possibility of recognizing defective segments. After this check, the segments of the display can be controlled as for commercial displays, ie control of the inverse segments is only necessary if the display is to be checked again. Such a display has the advantage that the electronic circuits and control algorithms are only slightly compared to conventional displays. O
fügig geändert werden müssen - es ist lediglich die gemeinsame Ansteuerung der Segmente und Inverssegmente zur Durchführung der Kontrolle notwendig.have to be changed - it is only necessary to jointly control the segments and inverse segments to carry out the control.
Erfindungsgemäß ist auch die umgekehrte Vorgehensweise möglich, d. h. es wird eine Anzeige so konzipiert, daß sie dem Betrachter in ausgeschalteten Zustand als homogen dunkel erscheint. Dies kann beispielsweise mit einer Schadt-Helfrich-Anzeige erreicht werden, bei der die Polarisatoren gleichsinnig ausgerichtet sind. Beim Einschalten einer solchen Anzeige wird erfindungsgemäß zunächst eine Ansteuerung aller Segmente und Inverssegmente vorgenommen. Liegen nunmehr fehlerhafte Segmente vor, so heben sich diese dunkel von der im übrigen hellen Anzeige ab. Die eigentliche Anzeige darzustellender Informationen kann nunmehr auf zwei Wegen erfolgen:According to the invention, the reverse procedure is also possible; H. an advertisement is designed in such a way that it appears homogeneously dark to the viewer when it is switched off. This can be achieved, for example, with a Schadt-Helfrich display in which the polarizers are aligned in the same direction. When such a display is switched on, all segments and inverse segments are first activated according to the invention. If there are now defective segments, they stand out darkly from the otherwise bright display. The actual display of information to be displayed can now take place in two ways:
Bei der ersten Vorgehensweise werden die darzustellenden Segmente angesteuert, so daß sie gegenüber der ansonsten dunklen Anzeige hell erscheinen. Die angesteuerten Segmente bilden lichtdurchlässige Bereiche. Wird eine Hintergrundbeleuchtung der Anzeigevorrichtung vorgesehen, so erscheinen dem Betrachter die angesteuerten Segmente leuchtend. Diese Betriebsart kann vorteilhaft für Anzeigen eingesetzt werden, die bei Dunkelheit abgelesen werden, wie z. B. Tachometer, Autoradios. Fieberthermometer etc..In the first procedure, the segments to be displayed are activated so that they appear bright compared to the otherwise dark display. The controlled segments form translucent areas. If backlighting of the display device is provided, the controlled segments appear to the viewer to be illuminated. This operating mode can be used advantageously for displays that are read in the dark, such as. B. speedometer, car radios. Clinical thermometer etc.
Bei einer zweiten Vorgehensweise erfolgt die Ansteuerung der Anzeige invers zur üblichen Ansteuerung, d. h. alle Segmente, die nicht dargestellt werden sollen, sowie die Inverssegmente. werden angesteuert, während die darzustellenden Segmente nicht angesteuert werden und demgemäß dunkel bleiben.In a second procedure, the display is activated inversely to the usual activation, i. H. all segments that should not be shown, as well as the inverse segments. are activated while the segments to be displayed are not activated and accordingly remain dark.
Zum Ansteuern einer erfindungsgemäßen Flüssigkristallanzeige können die im Stand der Technik bekannten Ansteuerungsvorrichtungen für konventionelle Flüssigkristallanzeigen verwendet werden. Bei den Ansteuerungsvorrichtungen müssen lediglich zusätzlich ein oder mehrere elektrische Ausgänge für die Inverssegmente vorgesehen werden, mit denen diese selektiv (d. h. von den regulären Segmenten getrennt) angesteuert werden können. Elektronische Ansteuerbausteine für Flüssigkristallanzeigen sind beispielsweise in dem Datenbuch "Philips Bauelemente", (1989) erschienen in Dr. Alfred Hüthing Verlag GmbH beschrieben (siehe z. B. PCF 8576). The control devices known in the prior art for conventional liquid crystal displays can be used to drive a liquid crystal display according to the invention. In the case of the control devices, it is only necessary to additionally provide one or more electrical outputs for the inverse segments, by means of which these can be controlled selectively (i.e. separately from the regular segments). Electronic control components for liquid crystal displays are, for example, in the data book "Philips Components", (1989) published in Dr. Alfred Hüthing Verlag GmbH (see e.g. PCF 8576).

Claims

Patentansprüche claims
1. Flüssigkristallanzeige, die ein visuelles Erkennen fehlerhafter Segmente ermöglicht, mit einer ersten und einer zweiten Platte, die gegenüberliegend angeordnet sind und sich im Zwischenraum zwischen erster und zweiter Platte eine flüssigkristalline Substanz befindet, die erste Platte transparent ist und in einem Anzeigebereich im wesentlichen transparente, leitfähige Segmente zur Darstellung von Symbolen aufweist und die zweite Platte zumindest in bestimmten Flächenbereichen leitfähig ist, dadurch gekennzeichnet, daß die erste Platte mindestens ein leitfähiges Inverssegment aufweist, das zumindest einen die Segmente zur Darstellung von Symbolen umgebenden Bereich des Anzeigebereiches ausfüllt.1. Liquid crystal display, which enables visual recognition of defective segments, with a first and a second plate, which are arranged opposite one another and a liquid-crystalline substance is located in the space between the first and second plate, the first plate is transparent and essentially transparent in a display area , has conductive segments for displaying symbols and the second plate is conductive at least in certain surface areas, characterized in that the first plate has at least one conductive inverse segment which fills at least one area of the display area surrounding the segments for displaying symbols.
2. Flüssigkristallanzeige gemäß Anspruch 1, bei der die Segmente sowie das mindestens eine Inverssegment separat voneinander mit einem elektrischen Potential beaufschlagt werden.2. Liquid crystal display according to claim 1, in which the segments and the at least one inverse segment are acted upon separately from one another with an electrical potential.
3. Flüssigkristallanzeige gemäß Anspruch 1, bei der die zweite Platte leitfähige Segmente aufweist, die den Segmenten der ersten Platte in Form und Größe im wesentlichen entsprechen und die so angeordnet sind, daß sich entsprechende Segmente gegenüberstehen.3. A liquid crystal display according to claim 1, wherein the second plate has conductive segments which substantially correspond in shape and size to the segments of the first plate and which are arranged such that corresponding segments face each other.
4. Flüssigkristallanzeige gemäß Anspruch 1, bei der die zweite Platte ein Inverssegment besitzt, das dem Inverssegment der ersten Platte in Form und Größe im wesentlichen entspricht.4. A liquid crystal display according to claim 1, wherein the second plate has an inverse segment which substantially corresponds in shape and size to the inverse segment of the first plate.
5. Flüssigkristallanzeige gemäß Anspruch 1, bei der die zweite Platte sowie deren leitfähige Flächenbereiche transparent sind.5. A liquid crystal display according to claim 1, wherein the second plate and its conductive surface areas are transparent.
6. Flüssigkristallanzeige gemäß Anspruch 1, bei der entweder die zweite Platte reflektierend ist oder sich hinter der zweiten Platte eine reflektierende Schicht befindet.6. A liquid crystal display according to claim 1, wherein either the second plate is reflective or there is a reflective layer behind the second plate.
7. Flüssigkristallanzeige gemäß Anspruch 1, die zwei Polarisatoren aufweist, zwischen denen die flüssigkristalline Substanz angeordnet ist. 7. A liquid crystal display according to claim 1, which has two polarizers, between which the liquid crystalline substance is arranged.
8. System zur Anzeige von Symbolen, das eine visuelle Erkennung fehlerhafter Segmente ermöglicht, beinhaltend eine Flüssigkristallanzeige gemäß Anspruch 1 sowie eine Ansteuerungsvorrichtung zum selektiven Ansteuern der Segmente und des mindestens einen Inverssegmentes.8. System for displaying symbols, which enables visual detection of defective segments, including a liquid crystal display according to claim 1 and a control device for selectively controlling the segments and the at least one inverse segment.
9. System gemäß Anspruch 8. bei dem die Ansteuerungsvorrichtung für ein Zeitintervall eine gemeinsame Ansteuerung aller Segmente und des mindestens einen Inverssegmentes vornimmt, so daß ein Betrachter möglicherweise ausgefallene Segmente an ihrer gegenüber dem mindestens einen Inverssegment inversen Erscheinungsweise erkennen kann.9. System according to claim 8, wherein the control device performs a common control of all segments and the at least one inverse segment for a time interval, so that a viewer can recognize possibly failed segments by their inverse appearance compared to the at least one inverse segment.
10. System gemäß Anspruch 8. mit einem Schalter, mit dem eine gemeinsame Ansteuerung aller Segmente und des mindestens einen Inverssegmentes eingeleitet werden kann.10. System according to claim 8 with a switch with which a common control of all segments and the at least one inverse segment can be initiated.
11. Verfahren zum Betrieb einer Flüssigkristallanzeige gemäß Anspruch 1 , mit den folgenden Schritten:11. A method of operating a liquid crystal display according to claim 1, comprising the following steps:
a) gemeinsames Ansteuern aller Segmente der ersten Platte sowie des mindestens einen Inverssegmentes für ein erstes Zeitintervall, um einem Betrachter die Möglichkeit zu geben, ausgefallene Segmente an ihrer gegenüber dem mindestens einen Inverssegment inversen Erscheinungsweise zu erkennen,a) joint control of all segments of the first plate and of the at least one inverse segment for a first time interval, in order to give an observer the possibility of recognizing failed segments by their appearance which is inverse to that of the at least one inverse segment,
b) Darstellen von Symbolen mit der Flüssigkristallanzeige.b) Representing symbols with the liquid crystal display.
12. Verfahren gemäß Anspruch 11, bei dem der Anzeigebereich bei Durchführung von Schritt a) dunkel erscheint und sich fehlerhafte Segmente hell abheben.12. The method according to claim 11, wherein the display area appears dark when step a) is carried out and defective segments stand out brightly.
13. Verfahren gemäß Anspruch 11. bei dem der Anzeigebereich bei Durchführung von Schritt a) hell erscheint und sich fehlerhafte Segmente dunkel abheben.13. The method according to claim 11, wherein the display area appears bright when step a) is carried out and faulty segments stand out dark.
14. Verfahren gemäß Anspruch 11 , bei dem die Darstellung von Symbolen in Schritt b) durch Ansteuerung der darzustellenden Segmente erfolgt und nicht darzustellende Segmente sowie das mindestens eine Inverssegment unangesteuert bleiben. 14. The method according to claim 11, in which the representation of symbols in step b) is carried out by actuation of the segments to be represented and segments not to be represented and the at least one inverse segment remain uncontrolled.
5. Verfahren gemäß Anspruch 11, bei dem die Darstellung von Symbolen in Schritt b) durch Ansteuerung der nicht darzustellenden Segmente sowie aller vorhandenen Inverssegmente erfolgt. 5. The method according to claim 11, in which the representation of symbols in step b) is carried out by controlling the segments that are not to be represented and all the inverse segments present.
EP99968725A 1998-09-08 1999-09-04 Liquid crystal display system and method of operating a liquid crystal display device with visual failure control Expired - Lifetime EP1112529B1 (en)

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DE19840952 1998-09-08
DE19840952A DE19840952C1 (en) 1998-09-08 1998-09-08 LC display with failure control
PCT/EP1999/006523 WO2000014599A1 (en) 1998-09-08 1999-09-04 Lcd display with failure control

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DE19840952C1 (en) 2000-03-23
US6927749B1 (en) 2005-08-09
ES2177348T3 (en) 2002-12-01
ATE217423T1 (en) 2002-05-15
JP4967047B2 (en) 2012-07-04
JP2002524773A (en) 2002-08-06
JP2010286839A (en) 2010-12-24
DE59901417D1 (en) 2002-06-13
JP4808314B2 (en) 2011-11-02
EP1112529B1 (en) 2002-05-08

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