JP3632365B2 - Ferroelectric liquid crystal display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ferroelectric liquid crystal display device composed of a liquid crystal material including a ferroelectric liquid crystal capable of changing display resolution and display speed.
[0002]
[Prior art]
In recent years, personal computers and presentation applications can be obtained at low cost, and presentations using these and liquid crystal projectors capable of displaying large screens are becoming popular. Under these circumstances, ferroelectric liquid crystal panels composed of liquid crystal materials including ferroelectric liquid crystal are used for electronic blackboards for business conferences and education, taking advantage of the fact that there is no flicker and eyestrain even on a large screen. Application to is expected. On the other hand, there has been a drawback that the screen switching speed is slow due to the characteristic that the next line cannot be selected until after the response of the pixel is confirmed, or because of the alternating current.
[0003]
FIG. 6 is a block diagram of a conventional ferroelectric liquid crystal display device. As shown in FIG. 6, the conventional ferroelectric liquid crystal display device is composed of a liquid crystal material including a ferroelectric liquid crystal having row electrodes 2-1 to 2-n and column electrodes 3-1 to 3-m. A row electrode driver 2 and a column electrode driver 3 which are connected to the ferroelectric liquid crystal panel 1 and are respectively connected to the row electrodes 2-1 to 2-n and the column electrodes 3-1 to 3-m to drive display of the ferroelectric liquid crystal panel 1. A display data receiving unit 4 for receiving display data from a personal computer as a display data source, a data processing unit 5 for processing the received display data so as to be adapted to matrix driving, and a data processing unit 5 And a driver control unit 6 for controlling the row electrode driver 2 and the column electrode driver 3 based on the above.
[0004]
FIG. 7A is an exemplary diagram of conventional display data, and FIG. 7B is a timing chart showing the operation of a conventional ferroelectric liquid crystal display device. First, in a period A shown in FIG. 7B, the driver control unit 6 supplies the selective erasing pulse to the row electrodes 2-1 to 2-3, and the column electrode driver 3 supplies the column electrodes 3- Control to supply erase pulses to 1-3-5. As a result, the same voltage is supplied to all the pixels of a part of the ferroelectric liquid crystal panel 1 (corresponding to row 3 × column 5), and all the pixels are turned off (display clear).
[0005]
Next, in the period B, the driver control unit 6 supplies the selection pulse to the row electrode 2-1 by the row electrode driver 2, and supplies the non-selection pulse to the other row electrodes 2-2 and 2-3. To control. At the same time, according to the display data from the data processing unit 5, the driver control unit 6 causes the column electrode driver 3 to turn on the column electrode corresponding to the display ON in the first row (in this example, the column electrode 3-3). Is controlled so that an OFF pulse is supplied to column electrodes corresponding to display OFF (in this example, column electrodes 3-1 to 3-5). Thereby, the first row of a part of the ferroelectric liquid crystal panel 1 (corresponding to row 3 × column 5) is displayed according to the display data.
[0006]
Subsequently, also in the periods C and D, the display according to the display data can be performed by sequentially repeating the above-described processing for the second and third rows. When the selection for all rows is completed, the display content is retained due to the memory effect of the ferroelectric liquid crystal characteristics. Therefore, for still image display data such as a document, once the selection is completed, the display is completed and the display content is displayed. As long as the above does not change, there is no need to perform the above-described line sequential scanning.
[0007]
[Problems to be solved by the invention]
However, in the above conventional configuration, the display switching speed of the screen is proportional to the number of row electrodes constituting the ferroelectric liquid crystal panel 1, so that the display device is used for an electronic blackboard or the like, so that the screen is enlarged and the resolution is increased. In this case, there is a problem that the display speed becomes slow.
[0008]
Therefore, an object of the present invention is to provide a ferroelectric liquid crystal display device capable of switching between high-speed screen display and high-resolution display according to the application.
[0009]
[Means for Solving the Problems]
A ferroelectric liquid crystal display device according to the present invention includes a ferroelectric liquid crystal panel made of a liquid crystal material including a ferroelectric liquid crystal having row electrodes and column electrodes, and a row electrode driver for driving the ferroelectric liquid crystal panel. And a column electrode driver, a display data receiving unit for receiving display data, and a display pulse received by the display data receiving unit by simultaneously supplying a selection pulse to a plurality of row electrodes, and a single row electrode By supplying a selection pulse to the display data, the resolution of the display data source is converted to the display resolution in accordance with the display data, and the data processing unit for applying processing to match the matrix drive, and the display resolution and the display speed are switched. A display mode switching unit; and a driver control unit that controls the row electrode driver and the column electrode driver. It can realize a ferroelectric liquid crystal display device capable of variably controlling the display resolution and display speed in accordance with the display mode switching unit.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
2. A ferroelectric liquid crystal display device according to claim 1, wherein the ferroelectric liquid crystal panel is made of a liquid crystal material including a ferroelectric liquid crystal having a row electrode and a column electrode, and a row for driving the ferroelectric liquid crystal panel. An electrode driver and a column electrode driver; a display data receiving unit that receives display data; and a display data received by the display data receiving unit by simultaneously supplying a selection pulse to a plurality of row electrodes; By supplying selection pulses to the row electrodes, the data processing unit converts the resolution of the display data source to the display resolution according to the display data and applies processing to match the matrix drive, and the display resolution and display speed. A display mode switching unit for switching the driver, and a driver control unit for controlling the row electrode driver and the column electrode driver. Control unit, the display resolution and display speed can be variably controlled in accordance with the display mode switching unit.
[0011]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a ferroelectric liquid crystal display device according to an embodiment of the present invention. In FIG. 1, 1 is a ferroelectric liquid crystal panel, 2-1 to 2-n are row electrodes, and 3-1 to 3-m are column electrodes. 2 is a row electrode driver, and 3 is a column electrode driver. Further, 4 is a display data receiving unit that receives data from a personal computer as a display data source, 5 is a data processing unit that applies processing to the received display data so as to conform to matrix driving, and 6 is a row electrode driver. 2. A driver control unit for controlling the column electrode driver 3, and a display mode switching unit for switching display resolution and display speed.
[0012]
FIG. 2 is an explanatory diagram of the number of display pixels of the display data source and the ferroelectric liquid crystal display device in one embodiment of the present invention. This figure shows the correspondence between the display resolution of a personal computer as a display data source and the display resolution of a ferroelectric liquid crystal display device that displays it. Here, the display resolution of the personal computer is XGA (Extended Graphic Array) 1024 pixels × 768 pixels, and the display resolution of the ferroelectric liquid crystal display device is 3072 pixels × 2304 pixels. FIG. 3 is a relationship diagram between the display data source and the ferroelectric liquid crystal display device according to the embodiment of the present invention. Here, a part of the display of the personal computer and a part of the display of the ferroelectric liquid crystal display device displaying the part corresponding thereto are shown. Here, in the high-speed display mode (A), although the display resolution of the ferroelectric liquid crystal display device is higher than the display resolution of the personal computer as the display data source, the display is simply enlarged in both rows and columns. ing. On the other hand, in the high quality display mode (B), correction is performed in consideration of the display resolution, which indicates that the display is of high quality with high resolution compared to the high speed display mode (A).
[0013]
4 is a timing chart showing the high-speed display operation of the ferroelectric liquid crystal display device according to the embodiment of the present invention. FIG. 5 is a high-quality display of the ferroelectric liquid crystal display device according to the embodiment of the present invention. It is a timing chart which shows operation.
[0014]
The operation of the ferroelectric liquid crystal display device according to the present embodiment will be described below with reference mainly to FIGS. First, a display method when the display mode switching unit 7 is set to the high-speed display mode will be described with reference to FIG. In the period A shown in FIG. 4, the driver controller 6 supplies the selective erasing pulse to the row electrodes 2-1 to 2-9 by the row electrode driver 2, and the column electrodes 3-1 to 3-15 by the column electrode driver 3. Is controlled to supply an erasing pulse. As a result, the same voltage is supplied to all the pixels of a portion of the ferroelectric liquid crystal panel 1 (corresponding to row 9 × column 15), and all the pixels are turned off (display is cleared).
[0015]
Next, in period B, since the display mode switching unit 7 is in the high-speed display mode, the driver control unit 6 supplies the selection pulses to the row electrodes 2-1 to 2-3 and the other row The electrodes 2-4 to 2-9 are controlled to supply non-selection pulses. At the same time, according to the display data from the data processing unit 5, the driver control unit 6 causes the column electrode driver 3 to display column electrodes corresponding to display ON in the first to third rows (in this example, column electrodes 3-7 to 3-9). ) Is controlled such that an ON pulse is supplied to the column electrodes corresponding to display OFF (in this example, other than the column electrodes 3-7 to 3-9). Thereby, the first to third rows of a part (row 9 × column 15) of the ferroelectric liquid crystal panel 1 are displayed according to the display data.
[0016]
Subsequently, in the period C, the driver controller 6 supplies the selection pulses to the row electrodes 2-4 to 2-6 by the row electrode driver 2, and the other row electrodes 2-1 to 2-3 and 2-7 to 2-9 is controlled to supply a non-selection pulse. At the same time, in response to the display data from the data processing unit 5, the driver control unit 6 causes the column electrode driver 3 to display column electrodes corresponding to display ON in the second row (in this example, column electrodes 3-4 to 3-6, 3 −10 to 3-12), an ON pulse is applied to column electrodes corresponding to display OFF (in this example, column electrodes 3-1 to 3-3, 3-7 to 3-9, 3-13 to 3-15). ) Is controlled to supply an OFF pulse. Thereby, the fourth to sixth rows of a part of the ferroelectric liquid crystal panel 1 (corresponding to row 9 × column 15) are displayed according to the display data. In this way, the process of supplying the selection pulse in units of three is performed. Further, also in the period D, by repeating the processing in units of three, the display corresponding to the display data can be performed on the seventh to ninth lines.
[0017]
When the selection for all rows is completed, the display content is retained due to the memory effect of the ferroelectric liquid crystal characteristics. Therefore, if the still image display data is a document or the like, the display is completed once the selection is completed. As long as this does not change, it is not necessary to perform the line sequential scanning as described above. Accordingly, display completion of a part of the ferroelectric liquid crystal panel 1 (corresponding to row 9 × column 15) is after the end of the period D.
[0018]
On the other hand, a display method when the display mode switching unit 7 is set to the high quality display mode will be described with reference to FIG. In the period A shown in FIG. 5, since it is the same as the above-described high-speed display mode, it is omitted. Next, in the period B, the driver control unit 6 supplies the selection pulse to the row electrode 2-1, since the display mode switching unit 7 is in the high quality display mode, and the other row electrode 2- 2 to 2-9 are controlled so as to supply non-selection pulses. At the same time, in response to the display data from the data processing unit 5, the driver control unit 6 causes the column electrode driver 3 to turn on the column electrode corresponding to the display ON in the first row (in this example, the column electrode 3-8). Are controlled so that an OFF pulse is supplied to the column electrodes corresponding to display OFF (in this example, other than the column electrodes 3-8). Thereby, the first row of a part of the ferroelectric liquid crystal panel 1 (corresponding to row 9 × column 15) is displayed according to the display data. Note that the timing chart of the row electrode is omitted.
[0019]
Subsequently, in the period C, the driver control unit 6 performs control so that the row electrode driver 2 supplies a selection pulse to the row electrode 2-2 and supplies a non-selection pulse other than the other row electrodes 2-2. To do. At the same time, in response to the display data from the data processing unit 5, the driver control unit 6 causes the column electrode driver 3 to apply column electrodes corresponding to display ON in the second row (in this example, column electrodes 3-7 to 3-9). Controls the ON pulse to supply the OFF pulse to the column electrodes corresponding to display OFF (in this example, other than the column electrodes 3-7 to 3-9). Thereby, the second row of a part of the ferroelectric liquid crystal panel 1 (corresponding to row 9 × column 15) is displayed according to the display data. In this way, the process of giving the selection pulse in units of one is performed. Further, during the periods D, E, F,..., Display according to display data can be performed by repeating the above control.
[0020]
When the selection for all rows is completed, the display content is retained due to the memory effect due to the ferroelectric liquid crystal characteristics. Therefore, for still image display data such as a document, once the selection is completed, the display is completed and the content is As long as there is no change, it is not necessary to perform the line sequential scanning as described above. Therefore, the display of a portion of the ferroelectric liquid crystal panel 1 (corresponding to row 9 × column 15) is completed after the end of the period J. As described above, since the number of row electrodes that supply the selection pulse at a time differs according to the setting of the display mode switching unit 7, the display speed can be changed according to the number of rows selected at a time.
[0021]
Here, the personal computer is XGA compatible as the display data source, and the display portion of the ferroelectric liquid crystal display device is 3072 pixels × 2304 pixels, which is three times the number of display pixels in both rows and columns. Although the selection pulse is given in this unit, it goes without saying that this is determined by the ratio of the display data source and the ferroelectric liquid crystal display device and is not limited to the unit of three. The display mode switching unit may be set from a personal computer or from a ferroelectric liquid crystal display device.
[0022]
【The invention's effect】
According to the present invention, a ferroelectric liquid crystal panel composed of a liquid crystal material including a ferroelectric liquid crystal having a row electrode and a column electrode, a row electrode driver and a column electrode driver for driving the ferroelectric liquid crystal panel, and The display data receiving unit that receives display data and the display data received by the display data receiving unit simultaneously supply a selection pulse to a plurality of row electrodes, and supply a selection pulse to a single row electrode. A data processing unit that converts the resolution of the display data source to the display resolution in accordance with the display data and performs processing so as to match the matrix drive, and a display mode switching unit that switches the display resolution and the display speed. A driver control unit that controls the row electrode driver and the column electrode driver, wherein the driver control unit includes the display module. The display resolution and display speed can be variably controlled in accordance with the de switching unit.
[Brief description of the drawings]
FIG. 1 is a block diagram of a ferroelectric liquid crystal display device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a display data source and the number of display pixels of the ferroelectric liquid crystal display device according to an embodiment of the present invention. FIG. 3 is a relationship diagram between a display data source and a ferroelectric liquid crystal display device according to an embodiment of the present invention. FIG. 4 shows a high-speed display operation of the ferroelectric liquid crystal display device according to an embodiment of the present invention. FIG. 5 is a timing chart showing a high-quality display operation of a ferroelectric liquid crystal display device according to an embodiment of the present invention. FIG. 6 is a block diagram of a conventional ferroelectric liquid crystal display device. A) Illustration of conventional display data (B) Timing chart showing the operation of a conventional ferroelectric liquid crystal display device
DESCRIPTION OF SYMBOLS 1 Ferroelectric liquid crystal panel 2 Row electrode driver 3 Column electrode driver 2-1 to 2-n Row electrode 3-1 to 3-m Column electrode 4 Display data receiving part 5 Data processing part 6 Driver control part 7 Display mode switching part

Claims (1)

A ferroelectric liquid crystal panel composed of a liquid crystal material including a ferroelectric liquid crystal having row electrodes and column electrodes, a row electrode driver and a column electrode driver for driving the ferroelectric liquid crystal panel, and receiving display data Display data received by the display data receiving unit and the display data received by the display data receiving unit by simultaneously supplying a selection pulse to a plurality of row electrodes and supplying a selection pulse to a single row electrode A data processing unit that converts the resolution of the display data source to the display resolution in accordance with the processing and applies processing to match the matrix driving, a display mode switching unit that switches display resolution and display speed, the row electrode driver, A driver control unit that controls the column electrode driver, the driver control unit corresponding to the display mode switching unit. Ferroelectric liquid crystal display apparatus characterized by variably controlling the display resolution display speed.

Images