KR20090105486A - Electrophoresis display - Google Patents

Abstract

PURPOSE: An electrophoresis display is provided to optimize a driving wave by reducing memory capacity and making a driving method simple. CONSTITUTION: An electrophoresis display includes a plurality of pixel electrode where a plurality of data lines and a plurality of gate lines are crossed and also includes a cell driven by a common voltage supplied to a common electrode. One driving wave is generated based on a comparison result of a current frame and a next frame and a mode selection information, the system determines data voltage and a common voltage level. A data driving circuit generates data voltage according to driving wave and supplies it to data line.

Description

Electrophoretic display {ELECTROPHORESIS DISPLAY}

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 capable of simplifying a circuit configuration by reducing a memory capacity and simplifying a driving scheme.

When a substance with a charge is placed in an electric field, the substance moves in a specific way depending on the charge, the size and shape of the molecule. Such behavior is referred to as electrophoresis, and the phenomenon of separation of materials due to the difference in movement is called electrophoresis. Recently, display apparatuses using such electrophoresis have been developed and attract attention as a medium to replace existing paper media or display elements.

An electrophoretic display device has been disclosed in US Pat. No. 7,012,600 and US Pat. No. 7,119,772, and the disclosed electrophoretic display device includes a look-up table (LUT) 1 and a plurality of memories 2 as shown in FIG. 4) and the image of the current state and the image of the next state for each cell using the frame counter 5, and as a result of the comparison, the data V1 to Vn supplied to each cell for a plurality of frame periods are determined. do.

The data V1 through Vn output from the lookup table 1 are digital data such as '00', '01', '10', and '11', and voltages of three states supplied to pixel electrodes of each cell, that is, Ve + , Ve-, Ve0. '00' and '11' convert to 0V, '01' converts to Ve + (+ 15V), and '10' converts to Ve-(-15V).

2 illustrates an example of a driving waveform supplied for a plurality of frame periods according to data written in a current state and data to be written in a next state. In FIG. 2, 'W (11)' represents peak white gray, 'LG (10)' represents bright medium gray, 'DG (01)' represents dark medium gray, and 'B (00)' represents peak black gray, The numbers listed below the drive waveform represent the number of frames.

The DC common voltage Vcom is supplied to the common electrode facing the pixel electrode. The positive data voltage Ve + supplied to the pixel electrode is higher than the DC common voltage Vcom and the negative data voltage Ve− is lower than the DC common voltage Vcom.

Such an electrophoretic display has the following problems.

First, in the conventional electrophoretic display device, since the number of gray scales of data is large, the lookup table 1 shown in FIG. ), The memory capacity and size become larger by the number of frames required. For example, as shown in FIG. 2, if the number of data gradations is four and the number of frames required for data update is 128, the memory capacity of the lookup table 1 is 4 ² x 128.

Second, in the conventional electrophoretic display device, since the number of frames required for updating the data is large so as to correspond to the number of gray levels of the data, a separate register for embedding frame information, which is the number of frame periods of digital data, and a separate number for counting the number of frames. By requiring a counter, the driving method and the circuit configuration are complicated.

Third, in the conventional electrophoretic display device, since the data voltage converted according to the digital data is relatively high at + 15V and -15V, the power consumption and size of the data drive integrated circuit (D-IC) are increased, thereby increasing the smart card. Difficult to apply to small applications such as mobile and mobile applications.

Fourth, the electrophoretic material has low fluidity at low temperature and high fluidity at high temperature. In the conventional electrophoretic display device, the electrophoretic material is uniformly controlled without considering these temperature characteristics, thereby providing flexibility to the panel temperature. Difficult to respond

Accordingly, an object of the present invention is to provide an electrophoretic display device which can reduce the capacity of the memory and simplify the circuit configuration by simplifying the driving method.

Another object of the present invention is to provide an electrophoretic display device capable of adaptively optimizing a driving waveform.

In order to achieve the above object, an electrophoretic display device according to an exemplary embodiment of the present invention is driven according to a data voltage applied to a pixel electrode and a plurality of gate lines intersected with a plurality of data lines and a common voltage applied to a common electrode. An electrophoretic display panel comprising cells; By storing a plurality of driving waveform information for the data voltage and the common voltage and generating any one of the driving waveform information based on the result of image comparison between the current frame and the next frame and the input mode selection information. System circuitry to determine levels; A data driving circuit which generates a data voltage according to the driving waveform information and supplies the data voltage to the data line; And a common voltage generating circuit selectively generating a DC common voltage or an AC common voltage according to the driving waveform information and applying the same to the common electrode.

The system circuit comprises: first and second frame memories for storing images of the current frame and the next frame; A user interface for receiving mode selection information from the outside; A mode table for storing gradation change information when the image is changed from an image of a current frame to an image of a next frame, and a plurality of driving waveform information according to mode classification information for a plurality of driving modes; Comparing images from the frame memories in units of cells, and using the comparison result and the mode selection information from the user interface, corresponding driving among a plurality of driving waveform information listed in the mode table in units of cells. A drive waveform selection unit for selecting waveform information; And a data generator for generating digital data corresponding to the selected driving waveform information and supplying the digital data to the data driving circuit.

The gradation change information is any one of information changed from peak black gradation to peak black gradation, peak black gradation to peak white gradation, peak white gradation to peak black gradation, and peak white gradation to peak white gradation.

The plurality of driving modes include first to third modes.

The drive waveform information consists of a combination of three or more detailed waveform information; Each of the detailed waveform information includes time information and level information of the data voltage and the common voltage at that time.

At a specific time of the first mode, the level information of the data voltage is determined to have any one of a positive voltage of a first level, a reference voltage, and a negative voltage of a first level, and the level of the common voltage. The information is determined to be maintained at the reference voltage; At a specific time of the second mode, the level information of each of the data voltage and the common voltage may be any one of a positive voltage of a second level having a half value of the first level, a reference voltage, and a negative voltage of a second level. Defined to have a value, wherein the potentials of the data voltage and the common voltage are reversed; At a specific time of the third mode, the level information of each of the data voltage and the common voltage is determined to have one of a positive voltage of a second level, a reference voltage, and a negative voltage of a second level. The potential of the data voltage and the common voltage is determined to be partially out of phase.

Each of the waveforms implemented by the detailed waveform information is generated within one frame.

The electrophoretic display further includes a temperature sensor for sensing a temperature of the electrophoretic display panel.

The driving waveform information listed in the mode table may be updated based on the sensing information from the temperature sensor.

In the electrophoretic display device according to the present invention, detailed waveform information of a data voltage and a common voltage for mono driving are predefined and stored in a memory, and a driving waveform is generated by a combination thereof, thereby reducing the number of grayscales and the number of frames. Capacity and size can be greatly reduced.

Furthermore, the electrophoretic display according to the present invention can simplify driving and circuits by eliminating a separate register for embedding frame information, which is the number of frame periods of digital data, and a separate counter for counting the number of frames.

Furthermore, the electrophoretic display according to the present invention can adaptively optimize the driving waveform according to the external environment by updating the driving waveform information of the mode table according to the temperature of the display panel.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 3 to 11.

3 and 4 illustrate an electrophoretic display and a cell according to an embodiment of the invention.

3 and 4, an electrophoretic display device according to an exemplary embodiment of the present invention includes an electrophoretic display panel 14 in which m × n cells 16 are arranged, and a data voltage of the electrophoretic display panel 14. Data driving circuit 12 for supplying the data lines D1 to Dm of the gate, gate driving circuit 13 for supplying the scan pulse to the gate lines G1 to Gn of the electrophoretic display panel 14, and A common voltage generating circuit 15 for supplying a common voltage Vcom to the common electrode 18 of the electrophoretic display panel 14, a timing controller 11 for controlling the data / gate driving circuits 12 and 13, By storing a plurality of driving waveform information about the data voltage and the common voltage and selecting one of the driving waveform information SM based on the image comparison result and the input mode information between the current frame and the next frame, the data voltage and the common voltage ( System circuit 10 for determining the level of Vcom, and A temperature sensor 19 for sensing the temperature of the kidongdong display panel 14 is provided.

The electrophoretic display panel 14 has a plurality of microcapsules 20 as shown in FIG. 4 interposed between two substrates. Each of the microcapsules 20 includes negatively-charged white particles 21 and positively-charged black particles 22. The m data lines D1 to Dm and the n gate lines G1 to Gn formed on the lower substrate of the electrophoretic display panel 14 cross each other. TFTs are connected to intersections of the data lines D1 to Dm and the gate lines G1 to Gn. The source electrodes of the TFTs are connected to the data lines D1 to Dm, and the drain electrodes thereof are connected to the pixel electrodes 17 of the cells 16. The gate electrodes of the TFTs are connected to gate lines G1 to Gn. The TFTs are turned on in response to the scan pulses from the gate lines G1 to Gn to select one line of cells 16 to be displayed. The common electrode 18 for simultaneously supplying the common voltage Vcom to all the cells is formed on the upper transparent substrate of the electrophoretic display panel 14.

Meanwhile, the microcapsules 20 may include positively charged white particles and negatively charged black particles. In this case, the phase and voltage of the driving waveform described later may vary.

The data driver circuit 12 is composed of a plurality of data driver integrated circuits each including a shift register, a latch, a digital-to-analog converter, an output buffer, and the like. The data driving circuit 12 latches digital data Data under the control of the timing controller 11, converts the digital data Data into a gamma compensation voltage, and supplies the data voltages to be supplied to the data lines D1 to Dn. Occurs.

The gate driving circuit 13 includes a shift register and a level shifter for converting the swing width of the output signal of the shift register into a swing width suitable for driving the TFT, and an output buffer connected between the level shifter and the gate lines G1 to Gn. A plurality of gate drive integrated circuits each include. The gate driving circuit 13 sequentially outputs scan pulses synchronized with the data voltages supplied to the data lines D1 to Dm.

The timing controller 11 receives the vertical / horizontal synchronization signals V and H and the clock signal CLK to generate control signals for controlling the operation timing of the data / gate driving circuits 12 and 13. In addition, the timing controller 11 links the digital data generated through the system circuit 10 to the data driving circuit 12 so as to correspond to the driving waveform information SM for each mode of the data voltage.

The common voltage generation circuit 15 selectively generates the first to third common voltages Vcom1 to Vcom3 in response to the mode-specific driving waveform information SM from the system circuit 10 and supplies them to the common electrode 18. do. Here, the first common voltage Vcom1 is a DC common voltage, and the second and third common voltages Vcom2 and Vcom3 are AC common voltages.

The temperature sensor 19 senses the temperature of the display panel and supplies the sensing information SS to the system circuit 10.

The system circuit 10 stores a plurality of driving waveform information about the data voltage and the common voltage Vcom, and any one of the driving waveform information SM based on the image comparison result between the current frame and the next frame and the input mode information. By selecting, the levels of the data voltage and the common voltage Vcom are determined. The system circuit 10 adaptively optimizes the driving waveforms by allowing the stored driving waveform information to be updated according to the sensing information SS from the temperature sensor 19.

5 is a detailed block diagram of the system circuit 10, and FIG. 6 shows an example of a mode table included in FIG.

5 and 6, the system circuit 10 according to an exemplary embodiment of the present invention may include a control signal generator 100, first and second frame memories 101 and 102, a drive waveform selector 103, and a user. An interface 104, a mode table 105, and a data generator 106 are provided.

The control signal generator 100 generates vertical / horizontal synchronization signals V and H and a clock signal CLK.

The first and second frame memories 101 and 102 respectively store an image of the current frame Fn and an image of the next frame Fn + 1.

The user interface 104 supplies the mode selection information Sel input by the user to the driving waveform selection unit 103. The mode selection information Sel is decoded by a decoder (not shown) and converted into a signal that can be processed by the drive waveform selection unit 103 and then supplied to the drive waveform selection unit 103. The user interface 104 may be implemented by any interface known in addition to an on screen display (OSD), a keyboard, a mouse, and a remote controller.

In the mode table 105, gray level change information (B-> B, B-> W, W-> B) is changed from the image of the current frame (Fn) to the image of the next frame (Fn + 1) as shown in FIG. , W-> W) and a plurality of driving waveform information according to the mode classification information (Mode1, Mode2, Mode3). Here, "W" represents peak white gradation and "B" represents peak black gradation. Each of the drive waveform information consists of a combination of three or more detailed waveform information. When the driving waveform information is configured by combining three detailed waveform information as shown in FIG. 6, the first two detailed waveform information functions to determine the driving waveforms of the data voltage and the common voltage during the initialization period. The waveform information determines a driving waveform of the data voltage and the common voltage during the data writing period. For example, "GC" of "GCD" is waveform information corresponding to an initialization section, and "D" is waveform information corresponding to a data writing section. Such detailed waveform information may be divided into seven types of "A" to "G" as in the embodiment of the present invention, each of which includes voltage classification information, voltage level information, and time information. This will be described in detail with reference to FIGS. 7A to 7G. The mode table 105 is a nonvolatile memory capable of updating and erasing data, for example, EEPROM (Electrically Erasable Programmable Read) so that the driving waveform information stored according to the sensing information SS from the temperature sensor 19 can be updated. Only Memory) and / or Extended Display Identification Data ROM (EDID ROM).

 The driving waveform selecting unit 103 compares the current frame input from the first and second frame memories 101 and 102 with the next frame-by-frame image in units of cells, and compares the result with the mode selection information from the user interface 104 ( The corresponding driving waveform information SM is selected from among the plurality of driving waveform information listed in the mode table 105 by Sel).

The data generator 106 generates digital data corresponding thereto in response to the drive waveform information SM from the drive waveform selector 103, and transmits the digital data through the timing controller 11. 12).

7A to 7G show waveforms of detailed waveform information for configuring driving waveform information. The detailed waveform information includes voltage classification information (data voltage and common voltage) and voltage level information (Ve +, Ve (1/2 +), Ve0, Ve (1 / 2-), and Ve- at a specific time, respectively. do.

As shown in FIG. 7A, the waveform information “A” is generated with the reference voltage Ve0 during the first period T1 and generated with the positive voltage Ve + of the first level during the second period T2. Waveform information of the data voltage Vdata generated as the reference voltage Ve0 during the third period T3 and the first common voltage Vcom1 generated as the reference voltage Ve0 during the first to third periods T1 to T3. ) Waveform information.

As shown in FIG. 7B, waveform information “B” is generated as the reference voltage Ve0 during the first period T1 and generated as the negative voltage Ve- of the first level during the second period T2. Waveform information of the data voltage Vdata generated as the reference voltage Ve0 during the third period T3 and the first common voltage generated as the reference voltage Ve0 during the first to third periods T1 to T3. Waveform information of Vcom1).

The waveform information "C" is generated as the reference voltage Ve0 during the first period T1 and the positive polarity voltage Ve (1/2 + of the second level during the second period T2 as shown in FIG. 7C. Waveform information of the data voltage Vdata generated as the reference voltage Ve0 during the third period T3, and generated as the reference voltage Ve0 during the first period T1, The waveform information of the second common voltage Vcom2 generated by the negative voltage Ve (1 / 2-) of the second level during the period T2 and generated by the reference voltage Ve0 during the third period T3 is included. . Here, the second positive voltage Ve (1/2 +) has a level 1/2 level of the first positive voltage Ve +, and the second negative voltage Ve (1 /). 2-)) has a 1/2 level magnitude of the negative voltage Ve- of the first level.

The waveform information "D" is generated as the reference voltage Ve0 during the first period T1 and the negative polarity voltage Ve (1 / 2−2) of the second level during the second period T2 as shown in FIG. 7D. Waveform information of the data voltage Vdata generated as the reference voltage Ve0 during the third period T3 and generated as the reference voltage Ve0 during the first period T1, and the second period T2. ) Is generated with the positive polarity voltage Ve (1/2 +) of the second level and includes waveform information of the second common voltage Vcom2 generated with the reference voltage Ve0 during the third period T3.

The waveform information "E" is generated with the negative voltage Ve (1 / 2-) of the second level during the first period T1 and the second level during the second period T2, as shown in FIG. 7E. Waveform information of the data voltage Vdata generated by the positive polarity voltage Ve (1/2 +) and generated by the negative polarity voltage Ve (1 / 2-) of the second level during the third period T3. And waveform information of the third common voltage Vcom3 generated at the negative voltage Ve (1 / 2−) of the second level during the first to third periods T1 to T3.

The waveform information "F" is generated with the positive polarity voltage Ve (1/2 +) of the second level during the first period T1 and the second level during the second period T2, as shown in FIG. 7F. Waveform information of the data voltage Vdata generated by the negative polarity voltage Ve (1 / 2−) of and generated by the positive polarity voltage Ve (1/2 +) of the second level during the third period T3. And waveform information of the third common voltage Vcom3 generated at the positive polarity voltage Ve (1/2 +) of the second level during the first to third periods T1 to T3.

As shown in FIG. 7G, the waveform information "G" includes waveform information of the data voltage Vdata generated as the reference voltage Ve0 during the sum period Tt of the first to third periods, and the first to third waveforms. Waveform information of the first common voltage Vcom1 generated as the reference voltage Ve0 during the sum period Tt of the period is included.

The levels of the common voltages Vcom1 to Vcom3 and the data voltage Vdata in the first and third periods T1 and T3 of FIGS. 7A to 7G are shown with a slight difference. This is to explain that the level of the common voltages can be adjusted to compensate for the deterioration in the charging characteristic of the data voltage Vdata due to the influence of the kickback voltage ΔVp due to the TFT characteristic. However, in the embodiment of the present invention, for convenience of description, it is assumed that the levels of the common voltages Vcom1 to Vcom3 and the data voltage Vdata are the same in each of the first and third periods T1 and T3.

In addition, in each of FIGS. 7A to 7G, the width of the second period T2 may be adjusted by updating data according to the sensing information SS from the temperature sensor 19. By updating such data, the width of the second period T2 may be narrowly adjusted as the temperature of the display panel increases. Accordingly, the present invention can adaptively optimize the driving waveform according to the temperature in consideration of the temperature characteristics of the electrophoretic material having low fluidity at low temperature but high fluidity at high temperature.

In addition, in each of FIGS. 7A to 7G, the summation period Tt of the first to third periods T1 to T3 is greatly reduced as compared to the conventional tens of frames by about one frame period. As described above, the reason for shortening the period for configuring one detailed waveform is reduced, as shown in the mode table of FIG. 6. In the present invention, the mono-drive with two gradations, that is, the peak black gradation B and the peak white gradation W This is because it is driven by a simple driving method. When the period for configuring one detailed waveform is reduced by about 1 frame, the period for configuring a drive waveform for data update is also reduced by about 3 frames. Accordingly, the electrophoretic display device according to the embodiment of the present invention can significantly reduce the memory capacity and size. Furthermore, the electrophoretic display device according to the exemplary embodiment of the present invention does not need a separate register for embedding frame information, which is a frame duration duration number of digital data, and a separate counter for counting the number of frames.

8A to 10D illustrate driving waveforms of a data voltage and a common voltage according to a change in gray level between frames for each mode.

8A to 10D, an electrophoretic display device according to an exemplary embodiment of the present invention is divided into an initialization period P1 including a reset period and a stabilization period, and a microcapsule 20 divided into a data writing period P2. Drive time division. When the driving waveform consists of a combination of three detail waveforms, the initialization period P1 consists of a combination of the first and second detail waveforms, and the data writing period P2 consists of third detail waveforms.

8A to 8D illustrate driving waveforms of the data voltage and the common voltage according to the grayscale change between frames in the first mode (Mode 1).

When the first mode Mode 1 is selected and the grayscale change between frames changes from black B to black B, the driving waveform is as shown in FIG. 8A. 8A corresponds to “ABA” driving waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information "AB", the white particles and the absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " A ", the data voltage Vdata, which is the first level of the positive polarity voltage Ve +, and the first common voltage Vcom1, which is the reference voltage Ve0, are used. In the cells, the negatively charged white particles of the microcapsules 20 move toward the pixel electrode 17 and the positively charged black particles move toward the common electrode 18, whereby peak black gradation B is realized. .

When the first mode (Mode 1) is selected and the grayscale change between frames changes from black (B) to white (W), the driving waveform is as shown in FIG. 8B. 8B corresponds to “GAB” driving waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information " GA ", the white particles and the absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. The data voltage Vdata, which is the negative voltage Ve- of the first level, and the first common voltage Vcom1, which is the reference voltage Ve0, are applied during the data writing period P2 corresponding to the detailed waveform information "B". The negatively charged white particles of the microcapsules 20 are moved toward the common electrode 18 and the positively charged black particles are moved toward the pixel electrode 17 in the corresponding cells, so that the peak white gray scale W is realized. do.

When the first mode Mode 1 is selected and the grayscale change between frames changes from white (W) to black (B), the driving waveform is as shown in FIG. 8C. 8C corresponds to “GBA” driving waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information "GB", the white particles and the absorbing particles in the microcapsules 20 are separated from each other and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " A ", the data voltage Vdata, which is the first level of the positive polarity voltage Ve +, and the first common voltage Vcom1, which is the reference voltage Ve0, are used. In the cells, the negatively charged white particles of the microcapsules 20 move toward the pixel electrode 17 and the positively charged black particles move toward the common electrode 18, whereby peak black gradation B is realized. .

When the first mode (Mode 1) is selected and the grayscale change between frames changes from white (W) to white (W), the driving waveform is as shown in FIG. 8D. FIG. 8D corresponds to “BAB” driving waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information " BA ", the white particles and the absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. The data voltage Vdata, which is the negative voltage Ve- of the first level, and the first common voltage Vcom1, which is the reference voltage Ve0, are applied during the data writing period P2 corresponding to the detailed waveform information "B". The negatively charged white particles of the microcapsules 20 are moved toward the common electrode 18 and the positively charged black particles are moved toward the pixel electrode 17 in the corresponding cells, so that the peak white gray scale W is realized. do.

 In the first mode Mode 1, since the first common voltage Vcom1 is maintained at the reference voltage Ve0, the level of the common voltage is stable. However, since the change range of the data voltage between the positive polarity voltage Ve + of the first level and the negative polarity voltage Ve + of the first level is large, power consumption and size of the data driving integrated circuit become large.

9A to 9D illustrate driving waveforms of the data voltage and the common voltage according to the grayscale change between frames in the second mode (Mode 2).

When the second mode (Mode 2) is selected and the gradation change between frames changes from black (B) to black (B), the driving waveform is as shown in FIG. 9A. 9A corresponds to the “CDC” drive waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information " CD ", the white particles and the absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " C " The negatively charged white particles of the microcapsules 20 in the cells are moved toward the pixel electrode 17 by the second common voltage Vcom2, which is (1 / 2-)) and the positively charged black particles are common. By moving toward the electrode 18, the peak black gradation B is realized.

When the second mode (Mode 2) is selected and the grayscale change between frames changes from black (B) to white (W), the driving waveform is as shown in FIG. 9B. 9B corresponds to the “GCD” drive waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information " GC ", the white particles and the absorbing particles in the microcapsules 20 are separated from each other and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " D ", the data voltage Vdata, which is the second negative voltage Ve (1 / 2-), and the positive voltage Ve of the second level, respectively. The negatively charged white particles of the microcapsules 20 in the cells are moved toward the common electrode 18 by the second common voltage Vcom2, which is (1/2 +), and the positively charged black particles are pixels. By moving toward the electrode 17, the peak white gradation W is realized.

When the second mode (Mode 2) is selected and the grayscale change between frames changes from white (W) to black (B), the driving waveform is as shown in FIG. 9C. 9C corresponds to “GDC” driving waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information " GD ", the white particles and the color absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " C " The negatively charged white particles of the microcapsules 20 in the cells are moved toward the pixel electrode 17 by the second common voltage Vcom2, which is (1 / 2-)) and the positively charged black particles are common. By moving toward the electrode 18, the peak black gradation B is realized.

When the second mode (Mode 2) is selected and the grayscale change between frames changes from white (W) to white (W), the driving waveform is as shown in FIG. 9D. FIG. 9D corresponds to the “DCD” drive waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information " DC ", the white particles and the absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " D ", the data voltage Vdata, which is the second negative voltage Ve (1 / 2-), and the positive polarity voltage Ve of the second level, respectively. The negatively charged white particles of the microcapsules 20 in the cells are moved toward the common electrode 18 by the second common voltage Vcom2, which is (1/2 +), and the positively charged black particles are pixels. By moving toward the electrode 17, the peak white gradation W is realized.

In the second mode (Mode 2), the variation range of the data voltage between the positive polarity voltage Ve (1/2 +) of the second level and the negative polarity voltage Ve (1 / 2-) of the second level is varied. Because of their small size, the power consumption and size of the data driver integrated circuit can be reduced, making it easy to apply to small applications such as smart card and mobile applications. In addition, the second common voltage Vcom2 is generated in the same magnitude and the opposite phase only in the positive / negative polarity period of the data voltage, and is generated as the reference voltage Ve0 in the same period as the data voltage in the period in which the polarity of the data voltage is changed. As a result, the level of the common voltage is relatively stable.

10A to 10D illustrate driving waveforms of the data voltage and the common voltage according to the grayscale change between frames in the third mode (Mode 3).

When the third mode (Mode 3) is selected and the grayscale change between frames changes from black (B) to black (B), the driving waveform is as shown in FIG. 10A. FIG. 10A corresponds to "EFE" driving waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information " EF ", the white particles and the absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " E ", the data voltage Vdata which is the second positive voltage Ve (1/2 +) and the negative voltage Ve of the second level are present. The negatively charged white particles of the microcapsules 20 in the cells are moved toward the pixel electrode 17 by the third common voltage Vcom3, which is (1 / 2-)) and the positively charged black particles are common. By moving toward the electrode 18, the peak black gradation B is realized.

When the third mode (Mode 3) is selected and the grayscale change between frames changes from black (B) to white (W), the driving waveform is as shown in FIG. 10B. FIG. 10B corresponds to the "GEF" drive waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information "GE", the white particles and the absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " F ", the data voltage Vdata which is the second negative voltage Ve (1 / 2-) and the positive polarity voltage Ve of the second level are provided. The negatively charged white particles of the microcapsules 20 in the cells are moved toward the common electrode 18 by the third common voltage Vcom3, which is (1/2 +), and the positively charged black particles are pixels. By moving toward the electrode 17, the peak white gradation W is realized.

When the third mode (Mode 3) is selected and the grayscale change between frames changes from white (W) to black (B), the driving waveform is as shown in FIG. 10C. FIG. 10C corresponds to "GFE" driving waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information " GF ", the white particles and the absorbing particles in the microcapsules 20 are separated from each other and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " E ", the data voltage Vdata which is the second positive voltage Ve (1/2 +) and the negative voltage Ve of the second level are present. The negatively charged white particles of the microcapsules 20 in the cells are moved toward the pixel electrode 17 by the third common voltage Vcom3, which is (1 / 2-)) and the positively charged black particles are common. By moving toward the electrode 18, the peak black gradation B is realized.

When the third mode (Mode 3) is selected and the grayscale change between frames changes from white (W) to white (W), the driving waveform is as shown in FIG. 10D. FIG. 10D corresponds to the “FEF” drive waveform information of FIG. 6. During the initialization period P1 corresponding to the detailed waveform information "FE", the white particles and the absorbing particles in the microcapsules 20 in the cells are separated and stabilized in a bistable state. During the data write period P2 corresponding to the detailed waveform information " F ", the data voltage Vdata which is the second negative voltage Ve (1 / 2-) and the positive polarity voltage Ve of the second level are provided. The negatively charged white particles of the microcapsules 20 in the cells are moved toward the common electrode 18 by the third common voltage Vcom3, which is (1/2 +), and the positively charged black particles are pixels. By moving toward the electrode 17, the peak white gradation W is realized.

In the third mode (Mode 3), the change range of the data voltage between the positive polarity voltage Ve (1/2 +) of the second level and the negative polarity voltage Ve (1 / 2-) of the second level is different. Because of their small size, the power consumption and size of the data driver integrated circuit can be reduced, making it easy to apply to small applications such as smart card and mobile applications. However, since the phase of the third common voltage Vcom3 periodically includes the positive / negative period of the data voltage, the phase of the third common voltage Vcom3 is not stable compared to the second mode.

11 shows an example in which each of the driving waveform information is configured by combining three or more detailed waveform information.

Referring to FIG. 11, the driving waveform information may be configured by combining various detailed waveform information even when the gray level between the current frame and the next frame is changed from black (B) to black (B) in the same mode. Although not shown, the same applies to the case of changing from black (B) to white (W), white (W) to black (B), and white (W) to white (W). This is because the register setting value of the mode table can be adjusted according to the characteristics of the electrophoretic material.

As described above, the electrophoretic display device according to the present invention predefines the detailed waveform information of the data voltage and the common voltage for mono driving, stores them in a memory, and generates driving waveforms by combining them. Can reduce the memory capacity and size significantly.

Furthermore, the electrophoretic display according to the present invention can simplify driving and circuits by eliminating a separate register for embedding frame information, which is the number of frame periods of digital data, and a separate counter for counting the number of frames.

Furthermore, the electrophoretic display according to the present invention can adaptively optimize the driving waveform according to the external environment by updating the driving waveform information of the mode table according to the temperature of the display panel.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a diagram showing a circuit for generating a data voltage waveform in a conventional electrophoretic display.

FIG. 2 is a diagram showing an example of a data voltage waveform listed in the lookup table shown in FIG. 1; FIG.

3 is a block diagram illustrating an electrophoretic display device according to an exemplary embodiment of the present invention.

4 is a view showing in detail the microcapsule structure of the cell shown in FIG.

FIG. 5 is a detailed configuration diagram of the system circuit shown in FIG. 3. FIG.

FIG. 6 is a diagram illustrating an example of a mode table illustrated in FIG. 5.

7A to 7G show waveforms of detailed waveform information for constructing driving waveform information.

8A through 8D are diagrams illustrating driving waveforms of a data voltage and a common voltage according to a change in gray level between frames in a first mode.

9A to 9D are diagrams illustrating driving waveforms of a data voltage and a common voltage according to a change in gray level between frames in a second mode.

10A to 10D are diagrams illustrating driving waveforms of a data voltage and a common voltage according to a change in gray level between frames in a third mode;

11 is a diagram illustrating an example in which each of driving waveform information is configured by combining three or more detailed waveform information.

<Description of Symbols for Main Parts of Drawings>

10: system circuit 11: timing controller

12: data driving circuit 13: gate driving circuit

14: electrophoretic display panel 15: common voltage generating circuit

16 cell 17 pixel electrode

18: common electrode 19: temperature sensor

100: control signal generator 101,102: frame memory

103: drive waveform selection unit 104: user interface

105: mode table 106: data generator

Claims (9)

An electrophoretic display panel including a plurality of data lines and a plurality of gate lines intersecting the plurality of data lines and cells driven according to a data voltage applied to the pixel electrode and a common voltage applied to the common electrode; By storing a plurality of driving waveform information for the data voltage and the common voltage and generating any one of the driving waveform information based on the result of image comparison between the current frame and the next frame and the input mode selection information. System circuitry to determine levels; A data driving circuit which generates a data voltage according to the driving waveform information and supplies the data voltage to the data line; And And a common voltage generating circuit selectively generating a DC common voltage or an AC common voltage according to the driving waveform information and applying the same to the common electrode. The method of claim 1, The system circuit, First and second frame memories for storing the image of the current frame and the next frame; A user interface for receiving mode selection information from the outside; A mode table for storing gradation change information when the image is changed from an image of a current frame to an image of a next frame, and a plurality of driving waveform information according to mode classification information for a plurality of driving modes; Comparing images from the frame memories in units of cells, and using the comparison result and the mode selection information from the user interface, corresponding driving among a plurality of driving waveform information listed in the mode table in units of cells. A drive waveform selection unit for selecting waveform information; And And a data generator for generating digital data corresponding to the selected driving waveform information and supplying the digital data to the data driving circuit. The method of claim 2, The gray scale change information may be any one of information changed from peak black gray to peak black gray, peak black gray to peak white gray, peak white gray to peak black gray, and peak white gray to peak white gray. Dynamic display. The method of claim 3, wherein The plurality of driving modes may include first to third modes. The method of claim 4, wherein The drive waveform information consists of a combination of three or more detailed waveform information; Wherein each of the detailed waveform information includes time information and level information of the data voltage and the common voltage at that time. The method of claim 5, wherein At a specific time of the first mode, the level information of the data voltage is determined to have any one of a positive voltage of a first level, a reference voltage, and a negative voltage of a first level, and the level of the common voltage. The information is determined to be maintained at the reference voltage; At a specific time of the second mode, the level information of each of the data voltage and the common voltage may be any one of a positive voltage of a second level having a half value of the first level, a reference voltage, and a negative voltage of a second level. Defined to have a value, wherein the potentials of the data voltage and the common voltage are reversed; At a specific time of the third mode, the level information of each of the data voltage and the common voltage is determined to have one of a positive voltage of a second level, a reference voltage, and a negative voltage of a second level. And the potential of the data voltage and the common voltage is partially reversed. The method of claim 5, wherein And each of the waveforms implemented by the detailed waveform information is generated within one frame. The method of claim 2, The electrophoretic display device further comprises a temperature sensor for sensing the temperature of the electrophoretic display panel. The method of claim 8, And the driving waveform information listed in the mode table can be updated based on the sensing information from the temperature sensor.

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