EP0394903A2 - Liquid crystal apparatus - Google Patents
Liquid crystal apparatus Download PDFInfo
- Publication number
- EP0394903A2 EP0394903A2 EP90107631A EP90107631A EP0394903A2 EP 0394903 A2 EP0394903 A2 EP 0394903A2 EP 90107631 A EP90107631 A EP 90107631A EP 90107631 A EP90107631 A EP 90107631A EP 0394903 A2 EP0394903 A2 EP 0394903A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- pulse
- scanning line
- scanning
- data
- liquid crystal
- 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
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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
- G09G3/36—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 using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3674—Details of drivers for scan electrodes
-
- 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
- G09G3/36—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 using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3622—Control of matrices with row and column drivers using a passive matrix
- G09G3/3629—Control of matrices with row and column drivers using a passive matrix using liquid crystals having memory effects, e.g. ferroelectric 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
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0202—Addressing of scan or signal lines
- G09G2310/0205—Simultaneous scanning of several lines in flat panels
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/04—Partial updating of the display screen
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/06—Details of flat display driving waveforms
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/06—Details of flat display driving waveforms
- G09G2310/061—Details of flat display driving waveforms for resetting or blanking
-
- 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
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0247—Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
Abstract
Description
- The present invention relates to a liquid crystal apparatus including a ferroelectric liquid crystal device and a multiplexing drive means.
- In recent years, the use of a bistable liquid crystal device has been proposed as an improvement to the conventional TN-liquid crystal device by Clark and Lagerwall (U.S. Patent No. 4,367,924, etc.). As the bistable liquid crystal, a ferroelectric liquid crystal having a chiral smectic C phase (SmC*) or H phase (SmH*) is generally used. The liquid crystal shows bistable states including a first and a second optically stable state in response to an electric field, so that the liquid crystal is oriented to, e.g., the first optically stable state in response to one electric field vector and to the second optically stable state in response to the other electric field vector. Further, the liquid crystal very quickly responds to an applied electric field to be oriented to either one of the two stable states and retains the resultant state in the absence of an electric field. By utilizing these properties, it is possible to attain a substantial improvement in problems accompanying the use of the conventional TN-type liquid crystal device.
- Further, many proposals have been made with respect to a driving method for multiplexing drive of such a bistable ferroelectric liquid crystal device, including those disclosed in U.S. Patents Nos. 4655561, 4638310, 4715688, 4701026, 4725129, 4770502, 4850676, etc.
- However these multiplexing drive methods proposed in the above patents involve the following problems.
- (1) The response speed of the liquid crystal per se is faster than that of a conventional TN-liquid crystal, but the frame frequency in matrix drive is low.
- (2) The range of voltage value or pulse duration of a drive pulse allowable for matrix drive, i.e., the drive margin, is narrow.
- As an improvement with respect to the above problem (1), the above-mentioned U.S. Patent No. 4770502 has proposed a driving method wherein selection terms for scanning lines are overlapped to each other to provide an increased frequency. This method is accompanied with a tendency that the drive margin (2) is further decreased, so that it has been difficult to satisfy a high frame frequency and a wide drive margin in combination by the conventional methods.
- An object of the present invention is to provide a ferroelectric liquid crystal apparatus which satisfies a higher frame frequency in multiplexing drive of a ferroelectric liquid crystal device while retaining a sufficient drive margin.
- According to the present invention, there is provided a liquid crystal apparatus, comprising:
a ferroelectric liquid crystal device comprising an electrode matrix including a plurality of scanning lines and a plurality of data lines intersecting with the scanning lines, and a ferroelectric liquid crystal disposed between the scanning lines and data lines, and
drive means for sequentially applying a scanning signal to the scanning lines for selecting a particular scanning line, and for applying data signals for the pixels on the selected scanning line to the data lines,
wherein each of the data signals has a plurality of pulses including a pulse in a controlled phase and a pulse in an auxiliary phase, and the scanning signal for the selected scanning line has a compensation pulse for compensating the pulse in the auxiliary phase of a data signal for a pixel on the selected scanning line. - These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
-
- Figure 1 is a waveform diagram showing a set of driving signal waveforms used in an embodiment of the liquid crystal apparatus according to the present invention.
- Figures 2A and 2B are time charts each showing time-serial waveforms based on unit drive signals shown in Figure 1.
- Figure 3 is a schematic view showing a display pattern on a liquid crystal device.
- Figures 4 and 5 are time charts each showing time-serial waveforms based on drive signals used in conventional methods.
- Figure 6 is a block diagram of a liquid crystal display apparatus and a graphic controller.
- Figure 7 is a time chart showing time correlation for image data communication between the liquid crystal display apparatus and the graphic controller.
- Figure 1 shows a set of driving signal waveforms used in an embodiment of the liquid crystal apparatus according to the present invention, in which a selection signal waveform is shown at (a), and data signal waveforms corresponding to "white" and "black" image data are shown at (b) and (c), respectively. Further, a voltage of, e.g., zero (not shown) is applied to scanning lines at the time of non-selection.
- Referring to the waveform at Figure 1(b), a phase having a pulse duration t₂ and a voltage value V₅ is a control phase, and phases having a pulse duration t₃ and a voltage value -V₄ are auxiliary phases. As described above, by using a data signal having these pulse phases, an image defect, such as flicker at the time of non-selection, can be alleviated. The selection signal waveform at Figure 1(a) comprises a clear or erasing phase having a pulse duration t₁ and a voltage value V₁, a control phase having a pulse duration t₂ and a voltage value -V₂, and an auxiliary phase having a pulse duration t₃ and a voltage value V₃, which is a phase for compensating an auxiliary phase of the data signal. Herein, the voltage V₃ is set to satisfy 0 < V₃ < V₁ and may preferably satisfy |V₃|=|V₄|. The provision of this compensation phase is a characteristic of the present invention, by which the above-mentioned drive margin is remarkably improved.
- Further, it is preferred that all the pixels on a selected scanning line are once simultaneously cleared into a black state.
- Figures 2A and 2B respectively show a time-serial waveform for providing a display as shown in Figure 3 based on unit drive signals shown in Figure 1.
- Referring to each of Figures 2A and 2B, at S₁ - S₄ are shown scanning signal waveforms applied to scanning lines s₁ - s₄ in Figure 3, at I₁ and I₂ are shown data signal waveforms applied to data lines i₁ and i₂, and at (I₁ - S₃) and (I₂ - S₂) are shown a combined waveform of the data signal waveform I₁ and scanning signal waveform S₃ and a combined waveform of the data signal waveform I₂ and scanning signal waveform S₂, respectively. Particularly, the sequence shown in Figure 2A is preferred so that a lower frame frequency can be set.
- A specific embodiment driven at a duty factor of 1/400 at room temperature provided an increased frame frequency of 1.3 times and an increased drive margin by about 10 % compared with a conventional drive embodiment shown in Figure 4. Further, compared with a conventional drive embodiment shown in Figure 5, an increased drive margin by about 50 % was attained.
- In the embodiment shown in Figure 1, it is preferred that the scanning signal (scanning selection signal) shown at Figure 1(a) have pulse durations t₁, t₂ and t₃ satisfying t₁:t₂:t₃ = 3 or more : 2 or more : 1, preferably 5-3 : 3-2 : 1, and peak values V₁ and V₂ satisfying |V₁| = |V₂| > 2|V₃|, preferably |V₁| = |V₂| > 2|V₃| to 4 |V₃|.
- Figures 4 and 5 respectively show time-serial waveforms used in a driving embodiment outside the present invention, in which at S₁ - S₄ are shown scanning signals applied to scanning lines s₁ - s₄, at I₁ and I₂ are shown data signals applied to data lines i₁ and i₂, and at (I₁ - S₃) and (I₂ - S₂) are shown combinations of I₁ and S₃ and I₂ and S₂, respectively, for providing a display pattern as shown in Figure 3. The drive waveforms are used in a type of driving method wherein all the pixels on a selected scanning line are once written in "black" and then retained in "black" or written in "white" selectively depending on given data. The drive waveforms are designed so as to alleviate "flickering" at the time of matrix drive, but the waveforms shown in Figure 4 are accompanied with a low frame frequency, and the waveforms shown in Figure 5 are accompanied with a small drive margin.
- Figure 6 is a block diagram showing an arrangement of a ferroelectric liquid
crystal display apparatus 601 and agraphic controller 602 provided in an apparatus body of, e.g., a personal computer as a source of supplying display data. Figure 7 is a time chart for communication of image data. - A
display panel 603 comprises a matrix electrode structure composed of 1120 scanning electrodes and 1280 data electrodes respectively disposed on a pair of glass plates and subjected to an aligning treatment, and a ferroelectric liquid crystal disposed between the glass substrates. The scanning electrodes (lines) and data electrodes (lines) are connected to a scanning line drive circuit 604 and a dataline drive circuit 605, respectively. - Hereinbelow, the operation will be explained with reference to the figures. The
graphic controller 602 supplies scanning line address data for designating a scanning line and image data (PD0 - PD3) on the scanning line designated by the address data to a display drive circuit 604/605 (composed of a scanning line drive circuit 604 and a data line drive circuit 605) of the liquidcrystal display apparatus 601. In this embodiment, the image data comprising the scanning line address data and the display data are transferred through the same transmission line, so that it is necessary to differentiate the above-mentioned two types of data. For the differentiation, a signal AH/DL is used. The AH/DL signal at a high level means scanning line address data, and the AH/DL signal at a low level means display data. - In the liquid
crystal display apparatus 601, the scanning line address data are extracted from transferred image data PD0 - PD3 by adrive control circuit 611 and then supplied to the scanning line drive circuit 604 in synchronism with a time for driving a designated scanning line. The scanning line address data are inputted to a decoder 606 in the scanning line drive circuit 604, and a designated scanning line in thedisplay panel 603 is driven by a scanningsignal generating circuit 607 with the aid of the decoder 606. On the other hand, the display data are introduced to ashift register 608 in the dataline drive circuit 605 and shifted by a unit of 4 pixel data based on a transfer clock signal. When the shift of display data for one horizontal scanning line is completed by theshift register 608, the display data for 1280 pixels are transferred to a line memory disposed in parallel, memorized for a period of one horizontal scanning and are supplied to the respective data lines as display data signals through a datasignal generating circuit 610. - Further, in this embodiment, the drive of the
display panel 603 in the liquidcrystal display apparatus 601 is not synchronized with the generation of the scanning line address data and display data in thegraphic controller 602, so that it is necessary to synchronize theapparatus drive control circuit 611 in the liquidcrystal display apparatus 601 at each one horizontal scanning period. Thegraphic controller 602 always monitors the SYNC signal, and transfers image data when the SYNC signal is at a low level and does not effect transfer after completing transfer of image data for one horizontal scanning line when the SYNC signal is at high level. More specifically, referring to Figure 7, thegraphic controller 602 immediately sets the AH/DL signal at high level and starts transfer of image data for one horizontal scanning line when it detects that the SYNC signal is at low level. Thedrive control circuit 611 in the liquidcrystal display apparatus 601 set to the SYNC signal at high level during the image data transfer period. When the writing in thedisplay panel 603 is completed after a prescribed one horizontal scanning period, the drive controller circuit (FLCD controller) 611 returns the SYNC signal to the low level so that it can receive image data for a subsequent scanning line. -
- In the present invention, the data signal used has an auxiliary phase which alleviates flicker, etc., of an image but can increase the tendency of an unexpected inversion of a display state thereby, while the scanning signal has a pulse phase for compensating an ill effect of the pulse in the auxiliary phase of the data signal, whereby the drive margin is remarkably improved to provide a room for increasing the frame frequency so that both the drive margin and the frame frequency are increased.
- As described above, by providing a scanning signal waveform with a compensation phase, an increased speed and an increased drive margin are attained to provide remarkably improved driving characteristics.
- A liquid crystal apparatus includes: a ferroelectric liquid crystal device comprising an electrode matrix including a plurality of scanning lines and a plurality of data lines intersecting with the scanning lines, and a ferroelectric liquid crystal disposed between the scanning lines and data lines, and drive means for sequentially applying a scanning signal to the scanning lines for selecting a particular scanning line, and for applying data signals for the pixels on the selected scanning line to the data lines; wherein each of the data signals has a plurality of pulses including a pulse in a controlled phase and a pulse in an auxiliary phase, and the scanning signal for the selected scanning line has a compensation pulse for compensating the pulse in the auxiliary phase of a data signal for a pixel on the selected scanning line.
Claims (11)
a ferroelectric liquid crystal device comprising an electrode matrix including a plurality of scanning lines and a plurality of data lines intersecting with the scanning lines, and a ferroelectric liquid crystal disposed between the scanning lines and data lines, and
drive means for sequentially applying a scanning signal to the scanning lines for selecting a particular scanning line, and for applying data signals for the pixels on the selected scanning line to the data lines,
wherein each of the data signals has a plurality of pulses including a pulse in a controlled phase and a pulse in an auxiliary phase, and the scanning signal for the selected scanning line has a compensation pulse for compensating the pulse in the auxiliary phase of a data signal for a pixel on the selected scanning line.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1101733A JP2652886B2 (en) | 1989-04-24 | 1989-04-24 | Driving method of liquid crystal device |
JP101733/89 | 1989-04-24 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0394903A2 true EP0394903A2 (en) | 1990-10-31 |
EP0394903A3 EP0394903A3 (en) | 1991-09-18 |
EP0394903B1 EP0394903B1 (en) | 1995-07-19 |
Family
ID=14308464
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90107631A Expired - Lifetime EP0394903B1 (en) | 1989-04-24 | 1990-04-23 | Liquid crystal apparatus |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0394903B1 (en) |
JP (1) | JP2652886B2 (en) |
AT (1) | ATE125380T1 (en) |
DE (1) | DE69020942T2 (en) |
ES (1) | ES2074493T3 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1994007235A1 (en) * | 1992-09-23 | 1994-03-31 | Central Research Laboratories Limited | GREYSCALE ADDRESSING OF FLCDs |
US5321419A (en) * | 1991-06-18 | 1994-06-14 | Canon Kabushiki Kaisha | Display apparatus having both refresh-scan and partial-scan |
US5657041A (en) * | 1994-06-03 | 1997-08-12 | Samsung Display Devices Co., Ltd. | Method for driving a matrix liquid crystal display panel with reduced cross-talk and improved brightness ratio |
US6271817B1 (en) | 1991-03-20 | 2001-08-07 | Seiko Epson Corporation | Method of driving liquid crystal display device that reduces afterimages |
US6300925B1 (en) * | 1997-10-20 | 2001-10-09 | U.S. Philips Corporation | Display device |
DE102011007493A1 (en) * | 2011-04-15 | 2012-10-18 | Aeg Gesellschaft für Moderne Informationssysteme mbH | LCD for display device, has circuit arrangement that generates additional signals in form of electric voltage pulses, which are arranged chronologically before or after drive signals to avoid display flickering |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE69524013T2 (en) * | 1994-09-12 | 2002-06-06 | Canon Kk | Control for a ferroelectrical liquid crystal device |
JP3286503B2 (en) * | 1994-09-28 | 2002-05-27 | キヤノン株式会社 | Driving method of liquid crystal element and liquid crystal device using the driving method |
US6018330A (en) * | 1995-04-28 | 2000-01-25 | Canon Kabushiki Kaisha | Liquid crystal display apparatus |
US6061044A (en) * | 1995-05-30 | 2000-05-09 | Canon Kabushiki Kaisha | Liquid-crystal display apparatus |
US5734365A (en) * | 1996-01-25 | 1998-03-31 | Canon Kabushiki Kaisha | Liquid crystal display apparatus |
US5903251A (en) * | 1996-01-29 | 1999-05-11 | Canon Kabushiki Kaisha | Liquid crystal apparatus that changes a voltage level of a correction pulse based on a detected temperature |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2569294A1 (en) * | 1984-08-18 | 1986-02-21 | Canon Kk | DISPLAY PANEL AND ITS CONTROL METHOD |
US4765720A (en) * | 1986-07-22 | 1988-08-23 | Canon Kabushiki Kaisha | Method and apparatus for driving ferroelectric liquid crystal, optical modulation device to achieve gradation |
EP0306822A2 (en) * | 1987-08-31 | 1989-03-15 | Sharp Kabushiki Kaisha | Display system for ferroelectric liquid crystal |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2531683B2 (en) * | 1987-06-08 | 1996-09-04 | キヤノン株式会社 | Liquid crystal device |
-
1989
- 1989-04-24 JP JP1101733A patent/JP2652886B2/en not_active Expired - Fee Related
-
1990
- 1990-04-23 AT AT90107631T patent/ATE125380T1/en active
- 1990-04-23 DE DE69020942T patent/DE69020942T2/en not_active Expired - Fee Related
- 1990-04-23 ES ES90107631T patent/ES2074493T3/en not_active Expired - Lifetime
- 1990-04-23 EP EP90107631A patent/EP0394903B1/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2569294A1 (en) * | 1984-08-18 | 1986-02-21 | Canon Kk | DISPLAY PANEL AND ITS CONTROL METHOD |
US4765720A (en) * | 1986-07-22 | 1988-08-23 | Canon Kabushiki Kaisha | Method and apparatus for driving ferroelectric liquid crystal, optical modulation device to achieve gradation |
EP0306822A2 (en) * | 1987-08-31 | 1989-03-15 | Sharp Kabushiki Kaisha | Display system for ferroelectric liquid crystal |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6271817B1 (en) | 1991-03-20 | 2001-08-07 | Seiko Epson Corporation | Method of driving liquid crystal display device that reduces afterimages |
US5321419A (en) * | 1991-06-18 | 1994-06-14 | Canon Kabushiki Kaisha | Display apparatus having both refresh-scan and partial-scan |
WO1994007235A1 (en) * | 1992-09-23 | 1994-03-31 | Central Research Laboratories Limited | GREYSCALE ADDRESSING OF FLCDs |
US5657041A (en) * | 1994-06-03 | 1997-08-12 | Samsung Display Devices Co., Ltd. | Method for driving a matrix liquid crystal display panel with reduced cross-talk and improved brightness ratio |
US6300925B1 (en) * | 1997-10-20 | 2001-10-09 | U.S. Philips Corporation | Display device |
DE102011007493A1 (en) * | 2011-04-15 | 2012-10-18 | Aeg Gesellschaft für Moderne Informationssysteme mbH | LCD for display device, has circuit arrangement that generates additional signals in form of electric voltage pulses, which are arranged chronologically before or after drive signals to avoid display flickering |
DE102011007493B4 (en) * | 2011-04-15 | 2015-07-02 | BMG Gesellschaft für moderne Informationssysteme mbH | Liquid crystal display and method for its control |
Also Published As
Publication number | Publication date |
---|---|
ES2074493T3 (en) | 1995-09-16 |
JPH02281233A (en) | 1990-11-16 |
EP0394903B1 (en) | 1995-07-19 |
EP0394903A3 (en) | 1991-09-18 |
DE69020942T2 (en) | 1995-11-23 |
DE69020942D1 (en) | 1995-08-24 |
ATE125380T1 (en) | 1995-08-15 |
JP2652886B2 (en) | 1997-09-10 |
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