WO2000004529A1 - Method for operating a liquid crystal display device and liquid crystal display device with temperature compensation - Google Patents

Method for operating a liquid crystal display device and liquid crystal display device with temperature compensation Download PDF

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Publication number
WO2000004529A1
WO2000004529A1 PCT/DE1999/002018 DE9902018W WO0004529A1 WO 2000004529 A1 WO2000004529 A1 WO 2000004529A1 DE 9902018 W DE9902018 W DE 9902018W WO 0004529 A1 WO0004529 A1 WO 0004529A1
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WO
WIPO (PCT)
Prior art keywords
display device
cathode tube
cold cathode
energy supply
temperature
Prior art date
Application number
PCT/DE1999/002018
Other languages
German (de)
French (fr)
Inventor
Jürgen HABICHER
Martin Michel
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Priority to JP2000560568A priority Critical patent/JP2002520794A/en
Priority to EP99945874A priority patent/EP1095368A1/en
Publication of WO2000004529A1 publication Critical patent/WO2000004529A1/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
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/041—Temperature compensation

Definitions

  • the invention relates to a method for operating an LCD display device which is backlit by a cold cathode tube, and an LCD display device with a cold cathode tube.
  • the measurement of the ambient temperature or the operating temperature does not have to be carried out directly on the cold cathode tube, but can also be carried out at a more distant location, provided that a relationship between the temperature at the installation location of the cold cathode tube and the measurement location is known. Nevertheless, it is advantageous to carry out the temperature measurement within the display device in order to be able to determine a heating of the cold cathode tube for optional regulation of the energy supply during the self-heating of the cold cathode tube.
  • the measure and / or the period of the increased energy supply for the cold cathode tube can be adapted to the heating behavior of the installation location of the display device for the type of vehicle for which the display device is intended.
  • a specific time period for the increased energy supply can be assigned to a specific ambient temperature of the cold cathode tube.
  • certain periods of time for the increased energy supply can be stored in a non-volatile memory for certain ambient temperatures or temperature ranges.
  • the energy supply is either continuously, stepwise or abruptly reduced to the energy supply in normal operation.
  • a suitable range for increasing the energy supply is between 20% and 70% of the energy supply during normal operation.
  • the invention is particularly suitable for TFT and DSTN color displays used in motor vehicles.
  • the figure shows an LCD display device with a cold cathode tube.
  • An LCD display device 1 with a TFT color display has a microprocessor 11, which is a controller. This controls a cold cathode tube 13 via a controllable current source 12. The current I with which the cold cathode tube 13 is operated is measured by a measuring element 14. A temperature sensor 15 measures the ambient temperature of the cold cathode tube within the housing of the display device 1. The measured values of the measuring element 14 and the temperature sensor 15 are fed to the microprocessor 11.
  • the temperature sensor 15 If the temperature sensor 15 outputs a temperature of less than 0 ° C. to the microprocessor 11, it controls the current source 12 in such a way that the cold cathode tube 13 is supplied with a current I of 9 mA instead of 6.5 mA.
  • the measuring element 14 continuously detects the current intensity with which the cold cathode tube 13 is applied, so that the microprocessor 11 can regulate precisely. If a temperature of 0 ° C is reached, the current increase is limited to approximately 25% above the normal operating current, i.e. approximately 7.8 mA. If the temperature sensor 15 measures an ambient temperature of approximately 20 ° C., the cold cathode tube 13 is operated with the normal operating current of approximately 6.5 mA.
  • the microprocessor 11 sets the nominal current for normal operation of the cold cathode tube 13 after 20 minutes, regardless of the operating temperature of the cold cathode tube that has been reached by then.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
  • Liquid Crystal Display Device Control (AREA)

Abstract

To compensate for the low light efficiency of a cold-cathode tube (3) at low temperatures the invention provides for the ambient temperature of the cold-cathode tube in a liquid crystal display device to be measured. When the temperature measured is below a limit value, the energy supplied to the cold-cathode tube is increased in relation to normal operations.

Description

Beschreibung description
VERFAHREN ZUM BETRIEB EINER LCD-ANZEIGEVORRICHTUNG UND LCD-ANZEIGEVORRICHTUNG MTI TEMPERATURKOMPENSATIONMETHOD FOR OPERATING AN LCD DISPLAY DEVICE AND LCD DISPLAY DEVICE MTI TEMPERATURE COMPENSATION
Die Erfindung betrifft ein Verfahren zum Betrieb einer LCD- Anzeigevorrichtung, die von einer Kaltkathodenröhre hinterleuchtet wird, und eine LCD-Anzeigevorrichtung mit einer Kaltkathodenröhre .The invention relates to a method for operating an LCD display device which is backlit by a cold cathode tube, and an LCD display device with a cold cathode tube.
In der Automobiltechnik eingesetzte Bildschirme werden teilweise bei sehr niedrigen Temperaturen betrieben. Im Winter kann es bei einem im Freien abgestellten Fahrzeug 20 Minuten oder länger dauern, bis eine Kaltkathodenröhre zur Hinter- leuchtung einer LCD-Anzeigevorrichtung die volle Leuchtleistung erreicht hat, da die Lichtausbeute dieses Röhrentyps temperaturabhängig ist. Insbesondere an hellen Wintertagen ist dadurch die Ablesbarkeit einer derartigen Anzeigevorrichtung über längere Zeit unbefriedigend.Screens used in automotive technology are sometimes operated at very low temperatures. In winter, when a vehicle is parked outdoors, it can take 20 minutes or more for a cold cathode tube for backlighting an LCD display device to reach full light output, since the light output of this type of tube is temperature-dependent. Particularly on bright winter days, the readability of such a display device is unsatisfactory over a long period.
Es ist ein Ziel der Erfindung, ein Verfahren zum Betrieb einer LCD-Anzeigevorrichtung und eine LCD-Anzeigevorrichtung mit einer Kaltkathodenröhre bereitzustellen, die eine Verbesserung der Anzeige bei sehr niedrigen Temperaturen ermögli- chen.It is an object of the invention to provide a method for operating an LCD display device and an LCD display device with a cold cathode tube, which enable an improvement of the display at very low temperatures.
Dieses Ziel wird mit einem Verfahren und einer LCD-Anzeigevorrichtung erreicht, wie sie in den unabhängigen Patentansprüchen definiert sind. Vorteilhafte Weiterbildungen der Er- findung sind in den Unteransprüchen angegeben.This aim is achieved with a method and an LCD display device as defined in the independent claims. Advantageous further developments of the invention are specified in the subclaims.
Durch die Erhöhung der Energiezufuhr für die Kaltkathodenröhre wird deren Lichtausbeute bei niedrigen Umgebungstemperaturen verbessert und die Eigenerwärmung der Anzeigevorrichtung beschleunigt. Eine Erhöhung der Energiezufuhr oder des Lampenstroms um 50 % für eine Dauer von fünf Minuten führt bei einer anfänglichen Betriebstemperatur von weniger als 0°C regelmäßig noch zu keiner Verminderung der Lebensdauer der Kaltkathodenröhre. Da die erhöhte Energiezufuhr nur bei unterschreiten einer bestimmten Umgebungstemperatur erfolgt, wird die Kaltkathodenröhre stets schonend betrieben.By increasing the energy supply for the cold cathode tube, its luminous efficiency is improved at low ambient temperatures and the self-heating of the display device is accelerated. A 50% increase in the energy supply or the lamp current for a period of five minutes at an initial operating temperature of less than 0 ° C does not regularly lead to a reduction in the life of the cold cathode tube. Since the increased energy supply only occurs when the temperature drops below a certain ambient temperature, the cold cathode tube is always operated gently.
Die Messung der Umgebungstemperatur oder der Betriebstemperatur muß nicht unmittelbar an der Kaltkathodenröhre erfolgen, sondern kann auch an einem entfernteren Ort vorgenommen werden, sofern eine Beziehung zwischen der Temperatur am Einbauort der Kaltkathodenröhre und dem Meßort bekannt ist. Dennoch ist es vorteilhaft die Temperaturmessung innerhalb der Anzeigevorrichtung vorzunehmen, um eine Erwärmung der Kaltkathodenröhre zur optionalen Regelung der Energiezufuhr während der Eigenerwärmung der Kaltkathodenröhre feststellen zu können.The measurement of the ambient temperature or the operating temperature does not have to be carried out directly on the cold cathode tube, but can also be carried out at a more distant location, provided that a relationship between the temperature at the installation location of the cold cathode tube and the measurement location is known. Nevertheless, it is advantageous to carry out the temperature measurement within the display device in order to be able to determine a heating of the cold cathode tube for optional regulation of the energy supply during the self-heating of the cold cathode tube.
Das Maß und/oder der Zeitraum der erhöhten Energiezufuhr für die Kaltkathodenröhre kann auf das Aufheizverhalten des Einbauortes der Anzeigevorrichtung für den Fahrzeugtyp angepaßt werden, für den die Anzeigevorrichtung vorgesehen ist. So kann beispielsweise einer bestimmten Umgebungstemperatur der Kaltkathodenröhre jeweils eine bestimmte Zeitdauer für die erhöhte Energiezufuhr zugeordnet werden. Zu diesem Zweck können für bestimmte Umgebungstemperaturen oder Temperaturbereiche bestimmte Zeitdauern für die erhöhte Energiezufuhr in ei- nem nichtflüchtigen Speicher gespeichert sein.The measure and / or the period of the increased energy supply for the cold cathode tube can be adapted to the heating behavior of the installation location of the display device for the type of vehicle for which the display device is intended. For example, a specific time period for the increased energy supply can be assigned to a specific ambient temperature of the cold cathode tube. For this purpose, certain periods of time for the increased energy supply can be stored in a non-volatile memory for certain ambient temperatures or temperature ranges.
Vorzugsweise wird nach einem definierten Zeitabschnitt oder bei Erreichen einer definierten Temperatur die Energiezufuhr entweder kontinuierlich, stufenweise oder abrupt auf die Energiezufuhr im Normalbetrieb zurückgeführt werden. Ein geeigneter Bereich für die Erhöhung der Energiezufuhr liegt zwischen 20 % und 70 % der Energiezufuhr des Normalbetriebs .Preferably, after a defined period of time or when a defined temperature is reached, the energy supply is either continuously, stepwise or abruptly reduced to the energy supply in normal operation. A suitable range for increasing the energy supply is between 20% and 70% of the energy supply during normal operation.
Die Erfindung eignet sich besonders gut für in Kraftfahrzeugen eingesetzte TFT- und DSTN- Farbdisplays.The invention is particularly suitable for TFT and DSTN color displays used in motor vehicles.
Weitere Vorteile, Merkmale und Anwendungsmöglichkeiten der Erfindung ergeben sich aus der Beschreibung eines bevorzugten Ausführungsbeispiels .Further advantages, features and possible uses of the invention result from the description of a preferred exemplary embodiment.
Die Figur zeigt eine LCD-Anzeigevorrichtung mit einer Kaltkathodenröhre.The figure shows an LCD display device with a cold cathode tube.
Eine LCD-Anzeigevorrichtung 1 mit einem TFT-Farbdisplay weist einen Mikroprozessor 11 auf, bei dem es sich um einen Controller handelt. Dieser steuert über eine regelbare Stromquelle 12 eine Kaltkathodenröhre 13. Von einem Meßglied 14 wird der Strom I gemessen, mit dem die Kaltkathodenröhre 13 betrieben wird. Ein Temperatursensor 15 mißt die Umgebungstemperatur der Kaltkathodenröhre innerhalb des Gehäuses der Anzeigevorrichtung 1. Die Meßwerte des Meßglieds 14 und des Temperatursensors 15 werden dem Mikroprozessor 11 zuge- führt.An LCD display device 1 with a TFT color display has a microprocessor 11, which is a controller. This controls a cold cathode tube 13 via a controllable current source 12. The current I with which the cold cathode tube 13 is operated is measured by a measuring element 14. A temperature sensor 15 measures the ambient temperature of the cold cathode tube within the housing of the display device 1. The measured values of the measuring element 14 and the temperature sensor 15 are fed to the microprocessor 11.
Gibt der Temperatursensor 15 eine Temperatur von weniger als 0°C an den Mikroprozessor 11 aus, so steuert er die Stromquelle 12 derart, daß die Kaltkathodenröhre 13 mit einem Strom I von 9 mA statt mit 6,5 mA versorgt wird. Das Meßglied 14 stellt kontinuierlich die Stromstärke fest, mit der die Kaltkathodenröhre 13 beaufschlagt ist, so daß eine genaue Regelung durch den Mikroprozessor 11 erfolgen kann. Wird eine Temperatur von 0°C erreicht, wird die Stromüberhöhung auf etwa 25 % über den normalen Betriebsstrom, also etwa auf 7,8 mA begrenzt. Wird vom Temperatursensor 15 eine Umgebungstemperatur von etwa 20°C gemessen, so wird die Kaltka- thodenröhre 13 mit dem normalen Betriebsstrom von etwa 6,5 mA betrieben.If the temperature sensor 15 outputs a temperature of less than 0 ° C. to the microprocessor 11, it controls the current source 12 in such a way that the cold cathode tube 13 is supplied with a current I of 9 mA instead of 6.5 mA. The measuring element 14 continuously detects the current intensity with which the cold cathode tube 13 is applied, so that the microprocessor 11 can regulate precisely. If a temperature of 0 ° C is reached, the current increase is limited to approximately 25% above the normal operating current, i.e. approximately 7.8 mA. If the temperature sensor 15 measures an ambient temperature of approximately 20 ° C., the cold cathode tube 13 is operated with the normal operating current of approximately 6.5 mA.
Um die Lebensdauer der Kaltkathodenröhre 13 nicht zu verkürzen, wird vorsorglich nach einem definierten Zeitraum die Stromüberhöhung beendet. In diesem Ausführungsbeispiel wird nach 20 Minuten unabhängig von der bis dahin erreichten Betriebstemperatur der Kaltkathodenröhre vom Mikroprozessor 11 der nominale Strom für den Normalbetrieb der Kaltkathodenröhre 13 eingestellt. In order not to shorten the lifespan of the cold cathode tube 13, the current excess is stopped as a precaution after a defined period of time. In this exemplary embodiment, the microprocessor 11 sets the nominal current for normal operation of the cold cathode tube 13 after 20 minutes, regardless of the operating temperature of the cold cathode tube that has been reached by then.

Claims

Patentansprüche claims
1. Verfahren zum Betrieb einer LCD-Anzeigevorrichtung (1), die von einer Kaltkathodenröhre (13) hinterleuchtet wird, mit den Schritten:1. A method for operating an LCD display device (1) which is backlit by a cold cathode tube (13), comprising the steps:
- die Umgebungstemperatur der Kaltkathodenröhre (13) wird gemessen,- The ambient temperature of the cold cathode tube (13) is measured,
- die Energiezufuhr zur Kaltkathodenröhre (13) wird gegenüber einer Energiezufuhr im Normalbetrieb erhöht, wenn die Umgebungstemperatur einen Grenzwert unterschreitet.- The energy supply to the cold cathode tube (13) is increased compared to an energy supply in normal operation if the ambient temperature falls below a limit.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Energiezufuhr nach einem definierten Zeitabschnitt oder bei Erreichen einer definierten Temperatur auf die Energiezufuhr im Normalbetrieb zurückgeführt wird.2. The method according to claim 1, characterized in that the energy supply is returned to the energy supply in normal operation after a defined period of time or when a defined temperature is reached.
3. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Strom der Kaltkathodenröhre (13) um 20% - 70% gegenüber dem Betriebsstrom bei Normalbetrieb erhöht wird.3. The method according to any one of the preceding claims, characterized in that the current of the cold cathode tube (13) is increased by 20% - 70% compared to the operating current in normal operation.
4. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Dauer der erhöhten Energiezufuhr auf das Aufheizverhalten des Einbauorts der LCD- Anzeigevorrichtung (1) in einem bestimmten Fahrzeugtyp angepaßt wird, für den die LCD-Anzeigevorrichtung bestimmt ist .4. The method according to any one of the preceding claims, characterized in that the duration of the increased energy supply is adapted to the heating behavior of the installation location of the LCD display device (1) in a specific type of vehicle for which the LCD display device is intended.
5. LCD-Anzeigevorrichtung mit einer Kaltkathodenröhre (13) zur Hinterleuchtung, die einen Temperatursensor (15) zur5. LCD display device with a cold cathode tube (13) for backlighting, which is a temperature sensor (15)
Ermittlung der Betriebstemperatur der Kaltkathodenröhre (13) und einen Mikroprozessor (11) aufweist, der bei Unterschreiten einer definierten Umgebungstemperatur die Energiezufuhr zur Kaltkathodenröhre (13) gegenüber einer Energiezufuhr im Normalbetrieb erhöht. Determination of the operating temperature of the cold cathode tube (13) and a microprocessor (11) which, when the temperature falls below a defined ambient temperature, increases the energy supply to the cold cathode tube (13) compared to an energy supply in normal operation.
PCT/DE1999/002018 1998-07-15 1999-07-01 Method for operating a liquid crystal display device and liquid crystal display device with temperature compensation WO2000004529A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2000560568A JP2002520794A (en) 1998-07-15 1999-07-01 Driving method of LCD display device and LCD display device
EP99945874A EP1095368A1 (en) 1998-07-15 1999-07-01 Method for operating a liquid crystal display device and liquid crystal display device with temperature compensation

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19831822.7 1998-07-15
DE1998131822 DE19831822C2 (en) 1998-07-15 1998-07-15 Method for operating an LCD display device and LCD display device

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WO2000004529A1 true WO2000004529A1 (en) 2000-01-27

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JP (1) JP2002520794A (en)
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3759133B2 (en) * 2003-08-29 2006-03-22 ローム株式会社 Power supply
JP2008122695A (en) * 2006-11-13 2008-05-29 Sharp Corp Liquid crystal display and its control method
DE102008017505B4 (en) * 2008-04-04 2010-09-09 Andreas Franz Karl Weyer Lamp with cold cathode lamp

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994009475A1 (en) * 1992-10-20 1994-04-28 Panocorp Display Systems Display device and its drive method
EP0642113A1 (en) * 1993-09-07 1995-03-08 Koninklijke Philips Electronics N.V. Display device with temperature compensation
EP0731438A2 (en) * 1995-02-27 1996-09-11 Canon Kabushiki Kaisha Display apparatus
US5774105A (en) * 1994-10-07 1998-06-30 Canon Kabushiki Kaisha Display apparatus with memory characteristic for storing system data

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4326415B4 (en) * 1993-08-06 2006-04-13 Siemens Ag Method for controlling a fluorescent lamp and arrangement for carrying out the method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994009475A1 (en) * 1992-10-20 1994-04-28 Panocorp Display Systems Display device and its drive method
EP0642113A1 (en) * 1993-09-07 1995-03-08 Koninklijke Philips Electronics N.V. Display device with temperature compensation
US5774105A (en) * 1994-10-07 1998-06-30 Canon Kabushiki Kaisha Display apparatus with memory characteristic for storing system data
EP0731438A2 (en) * 1995-02-27 1996-09-11 Canon Kabushiki Kaisha Display apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"COMPENSATION OF LIQUID CRYSTAL DISPLAY CONTRAST AND BRIGHTNESS FOR TEMPERATURE VARIATION", IBM TECHNICAL DISCLOSURE BULLETIN,US,IBM CORP. NEW YORK, vol. 36, no. 10, 10 October 1993 (1993-10-10), pages 381-382, XP000412299, ISSN: 0018-8689 *

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JP2002520794A (en) 2002-07-09
EP1095368A1 (en) 2001-05-02
DE19831822C2 (en) 2000-05-25
DE19831822A1 (en) 2000-01-20

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