KR20140028884A

KR20140028884A - Electrophoresis display device and method for driving the same

Info

Publication number: KR20140028884A
Application number: KR1020120096225A
Authority: KR
Inventors: 안지영
Original assignee: 엘지디스플레이 주식회사
Priority date: 2012-08-31
Filing date: 2012-08-31
Publication date: 2014-03-10
Also published as: KR101991744B1

Abstract

The present invention relates to an electrophoresis display device and a method of driving the same, capable of improving display quality by reducing the update time of an image and enhance grayscale expression. The method of driving the electrophoresis display device according to the embodiment of the present invention includes the steps of designing a plurality of waveforms including sub-frames in which only image data to make voltage, which is applied to a pixel by data voltage for the change from a present image to a next image and common voltage, to become 0V or more or to become 0V or less; selecting a waveform for the update of the next image among the waveforms based on the input image data; and supplying common voltage of 0V or -XV to the whole pixels if the image data of the sub-frame is formed such that the voltage applied to the pixel becomes 0V or more, and supplying the common voltage of 0V or +XV to the whole pixels if the image data of the sub-frame is formed such that the voltage applied to the pixel becomes 0V or less, wherein voltages corresponding to -2X, -X, 0, +X, and +2X are applied to the whole pixels, thereby updating the next image. [Reference numerals] (AA) Start; (BB) End; (S10) Design waveform to maximize sub-frame having image data of more than 0 (+1, 0) or less than 0 (-1, 0).; (S20) Loading waveform suitable for change of screen image.; (S30) Generate common voltage of +15V, 0V, or -15V according to image data.; (S40) Generate Vcom of -15V if image data is more than 0 (+1, 0).; (S50) Generate Vcom of +15V if image data is more than 0 (-1, 0).; (S60) Generate voltages of pixel corresponding to -30V, -15V, 0V, +15V, and 30V and drive data update at five level.

Description

ELECTROPHORESIS DISPLAY DEVICE AND METHOD FOR DRIVING THE SAME [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic display device, and more particularly, to an electrophoretic display device and a driving method thereof capable of improving display quality by reducing image update time and increasing gray scale expression.

An electrophoretic display device refers to an apparatus that displays an image using an electrophoresis phenomenon in which colored charged particles move by an electric field applied from the outside. Here, the electrophoresis phenomenon means that the charged particles move in the solvent by the Coulomb force when an electric field is applied while the charged particles are dispersed in the solvent.

The electrophoretic display apparatus using the electrophoretic phenomenon has a feature of bistable, and even if the applied voltage is removed, the displayed image can be displayed for a long time. That is, the electrophoretic display device is a display device suitable for the field of e-books that do not require a rapid exchange of the screen because it can maintain a constant screen for a long time even without applying a voltage continuously.

The electrophoretic display device is not only dependent on the viewing angle, but also reflects external light to display an image, thereby providing a comfortable image to the eye as much as paper.

The electrophoretic display device according to the prior art includes an opposing lower substrate, an upper substrate and an electrophoretic film. When an electric field is formed between the pixel electrode of the lower substrate and the common electrode of the upper substrate, the charged particles included in the microcapsule of the electrophoretic film are moved by electrophoresis to implement an image.

Moving the white charged particles toward the upper substrate reflects light incident from the outside, and moving the black charged particles toward the upper substrate absorbs the light incident from the outside. As such, the image is displayed by absorbing or reflecting light incident from the outside through the charged particles mounted on the electrophoretic film.

The electrophoretic display device can not display a frame on a frame-by-frame basis, such as an LCD, because the screen switching is not fast due to the bi-stability characteristic. Accordingly, the image is displayed by supplying the data voltage using a wave form, which is a sequence of image data, and the screen is switched from the previous image to the next image.

1 and 2 are views showing a method of driving an electrophoretic display device according to the prior art.

1 and 2, when switching screens through data update, the charged particles should be refreshed or initialized because the afterimage of the previous image may remain in the next image due to bistable characteristics. do.

The reset period is composed of a white reset period and a black reset period. In the white reset period, the charged particles are initialized, that is, the previous image is reset by supplying pixel data, for example, a positive (+) data voltage, so that the entire screen displays a white image for a plurality of subframes.

In the black reset period, the charged particles are initialized, that is, the previous image is reset by supplying pixel data, for example, a negative data voltage, so that the entire screen displays a black image during a plurality of subframes. After the reset period, the pixels are updated to switch the image data of the next image.

The electrophoretic display device according to the related art has a problem in that an image update time is long due to reset driving performed during a plurality of subframes.

The electrophoretic display device according to the related art supplies a common voltage of 0V to all pixels and applies a + 15V, 0V, or -15V data voltage, that is, a three-level data voltage, to each pixel during reset driving and data update driving. The data of the next image is updated.

Here, in order to finely control the gradation of the image, the number of subframes to which the data of the next image is supplied needs to be increased, thereby increasing the update time of the image.

On the other hand, in order to finely control the gradation representation of the image without increasing the update time of the image, the frequency can be increased to reduce the time of each subframe and increase the number of subframes. However, since the driving frequency and the power consumption are in a trade-off relationship, there is another problem that the power consumption increases due to the increase of the driving frequency.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophoretic display device and a method of driving the electrophoretic display device according to an embodiment of the present invention which can reduce the update time of an image when a screen is switched.

An object of the present invention is to provide an electrophoretic display device and a method of driving the electrophoretic display device which can improve the display quality by enhancing the gradation expressing power of an image when a screen is switched.

Other features and advantages of the invention will be set forth in the description which follows, or may be obvious to those skilled in the art from the description and the claims.

The driving method of the electrophoretic display device according to the embodiment of the present invention for achieving the above-described technical problem is such that the potential formed in the pixel by the data voltage and the common voltage for switching from the previous image to the next image is 0V or more. Designing a plurality of waveforms comprising subframes containing only image data or image data to be equal to or less than 0V; Selecting a waveform for updating a next image from among the plurality of waveforms based on the input image data; And supplying a common voltage of 0 [V] or -X [V] to all the pixels when the image data of the subframe is configured such that the potential formed in the pixel is 0 V or more, or the potential formed in the pixel is 0 V or less. Supplying a common voltage of 0 [V] or + X [V] to all the pixels when the image data of the subframe is configured to be equal to, and -2X, -X, 0, + X or + to all the pixels. The next image is updated by forming a potential corresponding to 2X.

Electrophoretic display device according to an embodiment of the present invention for achieving the above technical problem is a display panel having a plurality of pixels formed; A plurality of waveforms including a data frame for switching from the previous image to the next image and image data such that the potential formed in the pixel by the common voltage is 0V or more, or a subframe including only the image data to be 0V or less. Stored memory; A controller for selecting a waveform for switching of a next image among a plurality of waveforms based on the input image data; And generate a common voltage of -X [V] when the image data of the subframe is configured such that the potential formed in the pixel is equal to or greater than 0V, and the image data of the subframe is configured so that the potential formed in the pixel becomes equal to or less than 0V. And a data driver for generating a common voltage of + X [V] and supplying the common voltage to all the pixels of the display panel, and corresponding to -2X, -X, 0, + X, or + 2X for all the pixels of the display panel. A potential is formed to update the next image.

The electrophoretic display device and the driving method thereof according to the embodiment of the present invention can reduce the update time of the image when switching the screen.

The electrophoretic display device and the driving method thereof according to the embodiment of the present invention can enhance the gradation expressing power of the image and improve the display quality when switching the screen.

The electrophoretic display device and the driving method thereof according to the embodiment of the present invention can improve the display quality by eliminating the afterimage of the previous image.

Other features and effects of the present invention may be newly understood through the embodiments of the present invention in addition to the features and effects of the present invention mentioned above.

1 and 2 are views showing a driving method of an electrophoretic display device according to the related art.
3 is a view showing an electrophoretic display device according to an embodiment of the present invention.
4 shows an electrophoretic film type display panel.
5 shows a display panel of an internalization type;
6 to 11 are views showing a method of driving an electrophoretic display device according to an embodiment of the present invention.

Hereinafter, an electrophoretic display device and a driving method thereof according to an embodiment of the present invention will be described with reference to the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, detailed descriptions of configurations and functions known in the art and not related to the core configuration of the present invention may be omitted.

3 is a view showing an electrophoretic display device according to an embodiment of the present invention.

Referring to FIG. 3, an electrophoretic display (EPD) device according to an embodiment of the present invention includes a display panel 100 and a gate driver 200; A data driver 300; A controller 400, a power unit 500, and a memory 600.

The display panel 100 displays an image according to an inputted data voltage, and an electrophoresis layer is formed between the lower substrate and the upper substrate.

Here, as shown in FIG. 4, the electrophoretic layer may include an electrophoretic film 30 including a plurality of microcapsules on which charged particles and a solvent are mounted.

On the other hand, as shown in FIG. 5, partition walls 160 are formed to surround each pixel area, and the charged particles 172 and the solvent (172) are filled in the filling space provided by the partition walls 160. An internalization type filled with the display solvent 170 configured as 174 may be applied.

4 is a view showing a display panel of the electrophoretic film type, Figure 5 is a view showing a display panel of the internalization type.

4 and 5, a plastic substrate or a glass substrate is applied as the lower base substrate 102, and the TFT 140 is formed as a bottom gate structure as an example. A gate insulating layer 104 is formed between the gate G and the active A, and a protective layer 106 is formed to cover the TFT 140.

As shown in FIG. 5, in order to encapsulate the display solvent 170 filled in the filling space provided by the partition wall 160, a sealing layer 180 is formed on the partition wall 160.

On the other hand, the upper substrate 190 includes a transparent upper base substrate 192 and a common electrode 194. The common electrode 194 for supplying the common voltage Vcom to the plurality of pixels is formed on the upper base substrate 192.

Although not shown in the drawing, n gate lines and m data lines 130 are formed on the lower substrate 110 of the display panel 100. The gate lines are formed in the first direction, and the data lines are formed in the second direction so as to intersect the gate lines.

M x n pixels are formed in the form of a matrix by the intersection of the data lines and the gate lines. In each pixel, a TFT 140 is formed as a switching element, and a pixel electrode 150 for supplying a data voltage to the pixel is formed.

The TFT 140 switches the supply of image data, that is, a data voltage, to the pixel. The gate G of the TFT 140 is connected to the gate line 120. The data line is connected to the data voltage output portion (channel) of the data driver 300 and the source S of the TFT 140. And the drain D of the TFT 140 is connected to the pixel electrode 150. [

Referring back to FIG. 3, the power supply unit 500 may drive the driving voltages VCC and VSS required for driving the display panel 100 according to a preset power on sequence using the input power Vin. , Vcom, VPOS, VNEG, VGH, VGL).

The power supply unit 500 supplies the generated driving voltages VCC, VSS, Vcom, VPOS, VNEG, VGH, and VGL to the gate driver 200, the data driver 300, and the controller 400. In this case, the power-on sequence may be previously set in the controller 400 or an external host system or may be stored in a separate memory (EEPROM).

The power supply unit 500 generates a positive voltage VPOS voltage and a negative voltage VNEG based on a power supply control signal supplied from the controller 400. The VPOS voltage can be generated with a DC voltage of + 15V, and the VNEG voltage can be generated with a DC voltage of -15V. The power supply unit 500 supplies the generated VPOS voltage and the VNEG voltage to the data driver 300.

The logic power supply voltage VCC generated in the power supply unit 500 is a logic voltage required for driving the control unit 400, the data driver 300 and the gate driver 200, and is generally generated as a direct current voltage of +/- 3.3V.

VGL, which is a negative (-) gate voltage, is generated as a DC voltage of -20V to -22V and supplied to the gate driver 200, and VGH as a positive (+) gate voltage is generated as a DC voltage of +20V to + 22V And supplied to the gate driver 200.

The control unit 400 generates a gate control signal for controlling the gate driver 200 using the timing signal TS input from the outside and supplies the gate signal to the gate driver 200.

The control unit 400 generates a data control signal for controlling the data driver 300 and supplies the data control signal to the data driver 300.

Here, the timing signal TS includes a vertical synchronization signal V-sync, a horizontal synchronization signal H-sync, and a clock signal CLK.

When updating the image, the control unit 400 loads the waveform, which is a sequence of image data, from the memory 600 and supplies the waveform to the data driver 300.

The memory 600 stores a plurality of waveforms for conversion from the previous image to the next image.

The plurality of waveforms stored in the memory 600 are designed such that, when updating an image, only +1 or 0 of pixel data of one subframe exists. In addition, the plurality of waveforms are designed such that when the image is updated, only -1 or 0 of pixel data of one subframe exists.

A plurality of waveforms are designed to include a subframe in which only image data exists such that the potential formed in the pixel is 0V or more by the data voltage and the common voltage for switching from the previous image to the next image. A plurality of waveforms designed as described above are stored in the memory 600.

In addition, a plurality of waveforms are designed to include a subframe in which only image data exists such that the potential formed in the pixel becomes 0 V or less by the data voltage and the common voltage for switching from the previous image to the next image. A plurality of waveforms designed as described above are stored in the memory 600.

Here, all pixels are supplied with a common voltage Vcom having the same voltage value, and the common voltage Vcom may be generated with a 0V or ground GND voltage, or may be generated with an arbitrary + V or -V voltage. Pixel data of one subframe is generated in association with the common voltage, and one waveform is formed of a plurality of subframes.

When updating an image, the pixel data of one subframe is composed of +1 or 0, and a data voltage of + 15V or 0V is supplied to the pixel. Also,

The pixel data of one subframe is composed of -1 or 0, and a data voltage of -15V or 0V may be supplied to the pixel. In this case, the common voltage Vcom may be commonly supplied to all pixels at voltage values of −15V, 0V, or + 15V.

Apart from the data voltage according to the pixel data, the common voltage may be supplied at a voltage value of -15V, 0V, or + 15V. The memory 600 is supplied with a common voltage at a voltage value of -15V, 0V, or + 15V. In this regard, a plurality of pre-designed waveforms are stored.

The memory 600 may be a nonvolatile flash memory, a ROM, an EEPROM, or a magnetic computer storage medium.

The plurality of waveforms stored in the memory 600 may be generated in various versions reflecting the characteristics of materials constituting the electrophoresis layer and characteristics of a manufacturing process inherent to the manufacturer.

Different versions of the waveforms may be stored in the memory 600 of each of the plurality of electrophoretic display devices if the materials or manufacturers that make up the applied electrophoretic layer of the electrophoretic display device are different.

The gate driver 200 generates a scan pulse swinging between the gate high voltage VGH and the gate low voltage VGL based on the gate control signal supplied from the control unit 400. [

The gate driver 200 sequentially supplies scan pulses to the gate lines sequentially formed on the display panel 100 so that the reset voltage and the data voltage according to the waveform can be supplied to the pixels. At this time, the scan pulse is sequentially supplied to the plurality of gate lines in the reset period for refreshing the previous image and the data update period of the next image.

The movement characteristics of the charged particles are affected by the intensity of the applied voltage and the time of application of the voltage. The force for moving the charged particles becomes larger in proportion to the intensity of the voltage and the applied time. Even after the charged particles are moved by the voltage, the charged particles move little by little in the direction of movement due to inertia.

The migration characteristics of the charged particles vary depending on the type and amount of the particles and the viscosity of the solvent. The larger the force applied to the charged particles, the more the charged particles move due to the inertia to move.

It is said that the charged particles move to a desired position and then the charged particles remain in the current state without moving the charged particles, and that the bistability is good, and the bistable characteristic is the ratio of the charged particles and the material constituting the solvent It depends on the characteristics.

When the image is changed due to the bistability, the data voltage is applied to the pixels through a plurality of sub-frames, which increases the data update time.

Increasing the intensity of the voltage applied to the pixel can reduce the data update time, that is, update the next image with fewer sub-frames. However, since the output of the data voltage of the data driver 300 is fixed at -15V, 0V, and + 15V, there is a limitation in increasing the intensity of the voltage applied to the pixel.

In addition, in order to finely adjust the gradation of the image, the number of subframes to which the data of the next image is supplied must be increased, and the output of the data voltage is set at three levels of -15V, 0V, and + 15V. There was a limit to fine adjustment.

In the present invention, a data voltage and a common voltage are generated in multi-levels and supplied to each pixel in order to reduce the update time of the next image and increase the gradation expressing power of the image even in a small number of sub-frames. As an example, the reset of the previous picture and the next picture may be updated with five levels of image data.

When the image data of the subframe included in the waveform consists of +1 or 0, a data voltage of + X [V] or 0 [V] is supplied to each pixel, and a common voltage of -X [V] is applied to all pixels. Can be supplied to

On the other hand, when the image data of the sub-frame included in the waveform is composed of -1 or 0, the data voltage of ± [V] or 0 [V] is supplied to each pixel, and the common voltage of + X [V] is applied to all the pixels. Can be supplied to the pixel. As a result, potentials corresponding to −2X, −X, 0, + X, or + 2X may be formed in all the pixels, thereby performing update driving of the next image at twice the driving voltage as in the prior art.

In detail, the data driver 300 generates a common voltage Vcom and supplies it to the common electrode 194. In this case, the common voltage Vcom is generated as a DC voltage in the range of -15V to + 15V. For example, the common electrode 194 may be supplied with a common voltage having voltage values of −15V, 0V, and + 15V.

In addition, the data driver 300 continuously generates a data voltage using a waveform input from the controller 400, and supplies the generated data voltage to data lines formed in the display panel 100.

The data voltage supplied to the data lines in the data driver 300 is generated with a positive voltage, 0V and a negative voltage. When a scan pulse is applied to the gate line and the TFT 140 is turned on, a data voltage applied to the data line is applied to the pixel electrode 150 via the TFT 140.

The common voltage Vcom of -15V, 0V or + 15V is supplied to the common electrode 194 of the upper substrate 200, and the data of -15V, 0V or + 15V is supplied to the pixel electrode 150 of the lower substrate 100. The voltage is supplied to form an electric field of -30V, -15V, 0V, + 15V, or + 30V between the lower substrate 100 and the upper substrate 200.

Specifically, in the reset period, the data driver 300 generates a reset voltage according to the reset waveform input from the controller 400 and supplies the reset voltage to the pixels of the display panel 100 to reset the previous image. At this time, the data voltage of the white image and the data voltage of the black image are supplied to the pixels to reset the state of the charged particles.

The data driver 300 supplies a common voltage of 0V to the common electrode 194 in the reset period, and supplies a data voltage (-15V) to all the pixel electrodes 150 for displaying all pixels in white in the white reset period. Supply. Data voltages for displaying all pixels in white are supplied during a plurality of subframes.

The data driver 300 supplies a common voltage of 0 V to the common electrode 194 in the black reset period during the reset period, and applies a data voltage (+ 15V) for displaying all pixels as black to all the pixel electrodes 150. To feed. Data voltages for displaying all pixels in black are supplied during a plurality of subframes.

After the reset period, the data driver 300 supplies a data voltage for displaying the next image for a plurality of subframes, and a voltage value of -15V, 0V or + 15V, depending on the gray of the image to be displayed for each pixel. The branch data voltage is continuously supplied. In this way, the next screen is displayed by updating the data of the next image in the pixels. At this time, the common electrode 194 is supplied with a common voltage having a voltage value of + 15V or -15V.

For example, when the data voltage is supplied at + 15V and the common voltage is supplied at -15V, the potential difference is 30V, and the update driving of the image can be performed at twice the driving voltage compared to the conventional driving method.

In addition, when the data voltage is supplied at -15V and the common voltage is supplied at + 15V, the potential difference is 30V, and the update driving of the image can be performed at twice the driving voltage compared to the conventional driving method.

In this way, the data voltage is supplied to each pixel at three levels of +15 [V], 0 [V], or -15 [V] based on the image data of the subframe. The common voltage may be supplied to all the pixels at three levels of +15 [V], 0 [V], or -15 [V] based on the image data of the subframe. Therefore, the potential of -30 [V]-+30 [V] can be formed in all the pixels, thereby resetting the previous image and updating the next image.

When the data voltage is supplied at -15V, 0V, or + 15V, and the common voltage is supplied at -15V, 0V, or + 15V, the potential difference between the lower substrate 100 and the upper substrate 200 is -30V, -15V, 0V. Can be formed at five levels of + 15V and + 30V.

In this way, the data voltage and the common voltage are driven to a far level to reduce the type of update of the image and to finely adjust the gradation of the image.

6 to 11 are views illustrating a method of driving an electrophoretic display device according to an exemplary embodiment of the present invention.

6 and 7, a plurality of waveforms for screen switching from the previous picture to the next picture are designed and stored in the memory 600 (S10). In this case, a plurality of waves including a subframe including only image data such that the potential formed in the pixel becomes 0V or higher or data voltage 0V or less due to the data voltage and the common voltage for switching from the previous image to the next image. Design the form and store the designed wave form in memory 600.

The plurality of waveforms are designed such that there is only a subframe in which the image data for updating the next picture is +1, 0 or the image data has only -1, 0, or the subframe is designed to be the maximum. In this case, the plurality of waveforms stored in the memory 600 are designed such that, when an image is updated, a subframe having only +1, 0 or -1, 0 in which image data exists in one subframe is maximum.

However, the present invention is not limited thereto, and the plurality of waveforms may include subframes in which image data for updating the next image are all +1, 0, and -1.

Here, when the image data is +1, a data voltage of +15 V is supplied to the pixel electrode 150, and when the image data is 0, a data voltage of 0 V is supplied to the pixel electrode 150, and the image data is −. In the case of 1, the data voltage of -15V is supplied to the pixel electrode 150.

Subsequently, when the screen is switched from the previous image to the next image, after confirming the image data input from the controller 400, a waveform suitable for updating the next image is selected from among the plurality of waveforms stored in the memory 600, and the selected image is selected. Loading the waveform (S20). That is, a waveform suitable for updating the next image is selected from a plurality of waveforms based on the input image data.

Subsequently, a common voltage is generated as a voltage value of + 15V or -15V according to image data for updating the next image (S30). At this time, data of a common voltage having a voltage value of + 15V or -15V is also formed in a wave form.

Subsequently, when the image data of the subframe includes +1 and 0, as illustrated in FIG. 8, a data voltage of + 15V or 0V is supplied to the pixel electrode 150 of each pixel. In addition, a common voltage of −15 V is supplied to the common electrode 194 of all the pixels (S40).

When the data voltage is supplied at + 15V or 0V and the common voltage is supplied at -15V, as shown in FIG. 8, a potential of + 30V or + 15V is formed in each pixel based on the data voltage supplied to the pixel electrode. Therefore, the image can be updated with the driving voltage twice that of the conventional driving method.

On the other hand, when the image data of the sub-frame is -1 and 0, as shown in Figure 9, the data voltage of -15V or 0V is supplied to the pixel electrode 150 of each pixel. In addition, a common voltage of +15 V is supplied to the common electrode 194 of all the pixels (S50).

When the data voltage is supplied at -15V or 0V and the common voltage is supplied at + 15V, as shown in FIG. 9, a potential of -30V or -15V is formed in each pixel based on the data voltage supplied to the pixel electrode. Therefore, the image can be updated with the driving voltage twice that of the conventional driving method.

When the image data of the subframe is configured such that the potential formed in the pixel is equal to or greater than 0V, a common voltage of 0 [V] or -X [V] can be supplied to all the pixels. In addition, when the image data of the subframe is configured such that the potential formed in the pixel is equal to or less than 0V, a common voltage of 0 [V] or + X [V] can be supplied to all the pixels. The next image can be updated by forming a potential corresponding to -2X, -X, 0, + X or + 2X in all the pixels.

As such, when the data voltage is supplied at -15V, 0V, or + 15V, and the common voltage is supplied at a voltage value of -15V, 0V, or + 15V, that is, the common voltage is multi-level, the lower substrate 100 and the upper substrate ( The data update driving may be performed by forming potentials between the voltages 200) at five levels of -30V, -15V, 0V, + 15V, and + 30V.

As a result, the update driving of the image is performed at twice the voltage of the data voltage value output from the data driver 300, thereby reducing the update time.

In addition, by supplying data voltages at five levels of -30 V, -15 V, 0 V, +15 V, and +30 V, the display quality can be improved by finely adjusting the gradation of the image.

10 and 11, according to another embodiment of the present invention, not only the update time of the next image but also the reset period of the previous image may be shortened to shorten the overall update time for screen switching.

First, in the reset period, a common voltage of + 15V is supplied to the common electrode 194 in the white reset period, and a data voltage of -15V for displaying all pixels in white is supplied to all the pixel electrodes 150. Through this, all pixels are displayed in white to reset the previous image.

As such, when the data voltage is supplied at -15V and the common voltage is supplied at + 15V during the white reset period, a potential of 30V is formed in each pixel to reset the image at twice the high voltage of the output voltage of the data driver 300. Drive can be performed.

Subsequently, in the black reset period, a common voltage of -15V is supplied to the common electrode 194, and a data voltage of + 15V for displaying all pixels as black is supplied to all the pixel electrodes 150. This resets the previous image by displaying all pixels in black.

In this way, if the data voltage is supplied at + 15V and the common voltage is supplied at -15V during the black reset period, the potential of 30V is formed in each pixel to reset the image at twice the high voltage of the output voltage of the data driver 300. Drive can be performed.

As such, when the common voltage is applied at the multi-levels of +15 and -15V, the previous image can be reset at twice the driving voltage compared to the conventional driving method, thereby reducing the subframe of the reset period.

Subsequently, after the reset period, a data voltage for updating the next image is supplied for a plurality of subframes, and a data voltage having a voltage value of -15 V, 0 V or +15 V is supplied according to the gray of the image to be displayed for each pixel. Supply continuously.

When the image data of the subframe is composed of +1 and 0, as illustrated in FIG. 10, a data voltage of +15 V or 0 V is supplied to the pixel electrode 150 of each pixel. In addition, a common voltage of -15 V is supplied to the common electrode 194 of all the pixels.

If the data voltage is supplied at + 15V or 0V and the common voltage is supplied at -15V, the potential of + 30V or + 15V is formed in each pixel based on the data voltage supplied to the pixel electrode, which is twice the conventional driving method. The image can be updated with a driving voltage of.

On the other hand, when the image data of the sub-frame is -1 and 0, as shown in Figure 11, a data voltage of -15V or 0V is supplied to the pixel electrode 150 of each pixel. In addition, a common voltage of +15 V is supplied to the common electrode 194 of all the pixels.

If the data voltage is supplied at -15V or 0V and the common voltage is supplied at + 15V, the potential of -30V or -15V is formed in each pixel based on the data voltage supplied to the pixel electrode, which is twice the conventional driving method. The image can be updated with a driving voltage of.

As described above, when the data voltage is supplied at -15V, 0V, or + 15V, and the common voltage is supplied at a voltage value of -15V or + 15V, that is, the common voltage is supplied at multiple levels, the lower substrate 100 and the upper substrate ( The potential between 200) can be formed at five levels of -30 V, -15 V, 0 V, +15 V, and +30 V to perform the update driving of the image at twice the voltage of the data voltage value output from the data driver 300. have.

In this way, the data voltage is supplied to each pixel at three levels of +15 [V], 0 [V], or -15 [V] based on the image data of the subframe, and + based on the image data of the subframe. The common voltage can be supplied to all the pixels at three levels of 15 [V], 0 [V], or -15 [V]. Therefore, the potential of -30 [V]-+30 [V] can be formed in all the pixels, thereby resetting the previous image and updating the next image. In this case, the data for supplying the common voltage may also be formed in a wave form.

This allows the next image to be updated with fewer subframes than the prior art, and finely adjusts the gray level of the image by supplying image update voltages at five levels of -30V, -15V, 0V, + 15V, and + 30V. The display quality can be improved.

8 to 11 described above, when converting from the previous image to the next image, after displaying all the pixels as a white image, the black image is displayed to reset the previous image. Next, an example of displaying the next image by matching the gray of the next image with the white signal is illustrated. However, the present invention is not limited thereto, and the order of displaying the black image and the white image may be changed when resetting the previous image.

Although reset time and image update time may vary depending on the structure and material of the electrophoretic layer, the reset drive and image update drive can be performed at twice the high voltage of the prior art, thereby reducing the overall update time by more than 50%. Can be.

It will be understood by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: display panel 110: lower substrate
102: lower base substrate 104: gate insulating layer
106: protective layer 140: TFT
150: pixel electrode 160: barrier rib
170: Display solvent 172: charged particles
174: solvent 180: sealing layer
190: upper substrate 192: upper base substrate
194: common electrode 200: gate driver
300: data driver 400:
500: power supply unit 600: memory

Claims

A plurality of waveforms including a data frame for switching from the previous image to the next image and image data such that the potential formed in the pixel is equal to or greater than 0V or the subframe including only image data to be equal to or less than 0V. Designing;
Selecting a waveform for updating a next image from among the plurality of waveforms based on the input image data; And
When the image data of the subframe is configured such that the potential formed in the pixel is equal to or greater than 0 V, a common voltage of 0 [V] or -X [V] is supplied to all the pixels, or the potential formed in the pixel is 0 V or less. Supplying a common voltage of 0 [V] or + X [V] to all the pixels when the image data of the subframe is configured,
And a potential corresponding to -2X, -X, 0, + X or + 2X in all the pixels to update the next image.

The method of claim 1,
A data voltage of + X [V], 0 [V] or -X [V] is supplied to the pixel based on the image data of the subframe,
And a common voltage having a polarity opposite to that of the data voltage is supplied to all the pixels.

The method of claim 1,
Supply a data voltage of +15 [V] to the pixel;
By supplying a common voltage of -15 [V] to all the pixels,
And a potential of +30 [V] is formed in the pixel based on the common voltage.

The method of claim 1,
A data voltage of -15 [V] is supplied to the pixel,
By supplying a common voltage of +15 [V] to all the pixels,
And a potential of -30 [V] is formed in the pixel based on the common voltage.

The method of claim 1,
Supply a data voltage of 0 [V] to the pixel,
By supplying a common voltage of +15 [V] or -15 [V] to all the pixels,
And a potential of ± 15 [V] is formed in the pixel based on the common voltage.

The method of claim 1,
A data voltage is supplied to each pixel at three levels of +15 [V], 0 [V] or -15 [V] based on the image data of the subframe,
A common voltage is supplied to all the pixels at three levels of +15 [V], 0 [V] or -15 [V] based on the image data of the sub-frame,
And a potential of -30 [V] to +30 [V] in all the pixels to reset the previous image and update the next image.

A display panel on which a plurality of pixels are formed;
A plurality of waveforms including a data frame for switching from the previous image to the next image and image data such that the potential formed in the pixel by the common voltage is 0V or more, or a subframe including only the image data to be 0V or less. Stored memory;
A controller for selecting a waveform for switching of a next image among a plurality of waveforms based on the input image data; And
When the image data of the subframe is configured such that the potential formed in the pixel is equal to or greater than 0 V. When the common voltage of -X [V] is generated, and the image data of the subframe is configured so that the potential formed in the pixel becomes equal to or less than 0 V. A data driver generating a common voltage of + X [V] and supplying all pixels of the display panel;
And a potential corresponding to -2X, -X, 0, + X or + 2X in all the pixels of the display panel to update the next image.

8. The method of claim 7,
The data driver includes:
A data voltage of + X [V], 0 [V] or -X [V] is supplied to the pixel based on the image data of the subframe,
And a common voltage having a polarity opposite to that of the data voltage to all pixels.

8. The method of claim 7,
Supplying a data voltage of +15 [V] to the pixel and supplying a common voltage of -15 [V] to all the pixels to form a potential of +30 [V] in the pixel based on the common voltage,
In addition to supplying a data voltage of -15 [V] to the pixel, a common voltage of +15 [V] is supplied to all the pixels to form a potential of -30 [V] at the pixel based on the common voltage. Electrophoretic display device.

8. The method of claim 7,
A data voltage is supplied to each pixel at three levels of +15 [V], 0 [V] or -15 [V] based on the image data of the subframe,
A common voltage is supplied to all the pixels at three levels of +15 [V], 0 [V] or -15 [V] based on the image data of the sub-frame,
And a potential of -30 [V] to +30 [V] in all the pixels to reset the previous image and update the next image.