KR20090020988A - Driving apparatus and method for pixel of electro phoretic display - Google Patents

Abstract

An apparatus and a method for driving a pixel of an electrophoretic display device are provided to reduce a manufacturing cost by using a thin film diode with a metal-insulating layer-metal structure instead of the thin film transistor as a switching element. An image signal processing circuit(601) outputs image data by correcting an input image signal and outputs recess data for the image data. A timing generator(602) produces and outputs a timing signal for controlling a scan line driving circuit or a data line driving circuit. The scan line driving circuit(603) supplies the scan line signal to the electrophoretic material of each pixel arranged in the display region of the electrophoretic display panel in a matrix region. The data line driving circuit(604) supplies the data line signal to the electrophoretic material. A common voltage supply unit(605) selectively outputs a high voltage, a low voltage, and a common voltage of the null voltage applying section to the electrophoresis material. The display region(606) of the electrophoretic display panel determines the gradation which the corresponding pixel displays by receiving the common voltage.

Description

 Pixel driving device and method of electrophoretic display device {DRIVING APPARATUS AND METHOD FOR PIXEL OF ELECTRO PHORETIC DISPLAY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving technology of an electrophoretic display device. In particular, a thin film diode instead of a thin mart transistor is used as a switching element to lower the process cost of a lower substrate and to use the same without a further process of an EP film. A drive device and method are disclosed.

An electrophoretic display device (EPD) is an image display device using a phenomenon in which colloidal particles move to either polarity when a pair of electrodes to which a voltage is applied is immersed in a solution of a polyamide.

For example, in an electrophoretic display device in which an upper substrate and a lower substrate on which pixel electrodes are formed are disposed to face each other, and an electrophoretic film is interposed therebetween, when a negative voltage (−) is applied to the pixel electrodes, black particles ( +) Drops and white particles (-) rise, and white is observed on the upper substrate side. In addition, when a positive voltage is applied to the pixel electrode, white particles (−) fall, black particles (+) rise, and black is observed on the upper substrate side. In addition, when a predetermined voltage is applied to the pixel electrode to properly adjust the distribution of the black particles and the white particles, gray color is observed on the upper substrate side.

Such an electrophoretic display device does not use a backlight and has a wide viewing angle, high reflectivity, easy readability, and low power consumption, so it is expected to be spotlighted as an electric paper in the future.

Recently, many image display apparatuses using electrophoretic materials have been proposed, and examples thereof include US Patent US6961047B2, US7012600B2, and the like. 1 to 6 are views related to the US patent US6961047B2 for illustratively showing the driving principle of the electrophoretic device.

1 is an exploded perspective view showing the mechanical configuration of a conventional electrophoretic display panel, Figure 2 is a partial cross-sectional view thereof.

As shown in FIG. 1 and FIG. 2, the electrophoretic display panel A is opposed to a device substrate 100 such as a glass or a semiconductor on which the pixel electrode 104 is formed, and the common electrode 201 on the plane. A substrate 200 is provided. The device substrate 100 and the counter substrate 200 are maintained at a constant interval, and the electrode formation surfaces are attached to face each other. The space between the device substrate 100 and the counter substrate 200 is divided by a partition wall 110 having a constant height. Here, the partition wall 110 is provided so as to distinguish the pixel which is the display unit of the image. The space divided by the partition wall 110 is called a divided cell, and the dispersion system 1 is filled therein.

The dispersion system 1 is to disperse the electrophoretic particles 3 in the dispersion medium (2). Additives, such as surfactant, are added to the said dispersion medium 2 as needed. In the dispersion system 1, in order to avoid sedimentation caused by gravity of the electrophoretic particles 3, the specific gravity of the dispersion medium 2 and the specific gravity of the electrophoretic particles 3 are selected to be substantially equal.

In this way, since the plurality of split cells 11C are installed along the partition wall 110, the area in which the electrophoretic particles 3 can be moved is limited to the inside of the split cells 11C. In the dispersion system 1, dispersion of particles may be biased or condensation may occur in which a plurality of particles are combined to form a large mass. However, by using the partition wall 110 and forming the plurality of split cells 11C, it is possible to prevent a bad phenomenon and to improve the quality of the display image.

The electrophoretic display panel A is capable of full color display. In this case, three types of red, green, and blue are used as the dispersing system 1 in order to be able to display one color among the primary colors RGB in each pixel.

First, the dispersion system 1r corresponding to red (R) uses red particles as the electrophoretic particles 3r, and uses cyan color as the dispersion medium 2r. Iron oxide can be used as this electrophoretic particle 3r, for example. Dispersion system 1g corresponding to green G uses green particles as electrophoretic particles 3g and magenta as dispersion medium 2g. As the electrophoretic particles 3g, cobalt green pigment particles may be used. The dispersing system 1b corresponding to blue (B) uses blue particles as the electrophoretic particles 3b and uses a yellow color as the dispersion medium 2b. As the electrophoretic particles 3b, for example, cobalt blue pigment particles are used.

That is, the electrophoretic particles 3 reflect the display color, while the dispersion medium 2 uses the color corresponding to the color (the complementary color in the above example) that absorbs the display color. And the member of the opposing board | substrate 200 and the sealing material 202 is used. Therefore, when the electrophoretic particle 3 floats on the electrode opposite to the display surface, light of a wavelength corresponding to the display color is reflected by the electrophoretic particle 3, and the viewer recognizes the color according to the reflected light. . On the other hand, when the electrophoretic particles 3 are settled on the electrode opposite to the display surface, light having a wavelength corresponding to the display color is absorbed by the dispersion medium 2 so that the light of the wavelength does not arrive at the observer. The color will not be recognized. However, it is possible to control how the electrophoretic particles 3 are distributed in the thickness direction of the dispersion system 1 according to the direction and intensity of the electric field applied to the dispersion system 1. Therefore, the intensity of the light reflected by the electrophoretic particles 3 can be adjusted by using the electrophoretic particles 3 and the dispersion medium 2 absorbing the reflected light in combination and controlling the electric field strength. Results You can change the intensity of the light that reaches the viewer.

The display area A1 and the peripheral area A2 are provided on the surface of the device substrate 100. The display area A1 is divided by the partition wall 110, and therein, a thin film transistor (TFT) which functions as a scan line, a data line, and a switching element, which will be described later, elsewhere in the pixel electrode 104. ) Is formed. In the peripheral area A2 of the device substrate 100, a scan line driver circuit, a data line driver circuit, and an external connection electrode, which will be described later, are formed.

FIG. 3 is a block diagram of a conventional electrophoretic display device. As shown in FIG. 3, an electrophoretic display device includes an electrophoretic display panel A and a peripheral circuit of an image signal processing circuit 300A and a timing generator. (timing gene) 400 is provided.

The image signal processing circuit 300A performs correction processing corresponding to the electrical characteristics of the electrophoretic display panel A to the input image signal VID to generate and output image data D, and to output the image data D. Before outputting the data D, the reset data Drest is outputted for a predetermined period. The reset data Drest is used to attract the electrophoretic particles 3 moving in the dispersion system 1 to the pixel electrode 104 and to initialize the spatial state. In the following description, for the sake of simplicity, the dispersion medium 2 of the dispersing system 1 is colored black, and the electrophoretic particles 3 are white particles such as titanium oxide and reliably charged. Shall be.

In addition, the timing generator 400 generates various timing signals for controlling the scan line driver circuit 130 or the data line driver circuit 140A when the image data D is output from the image signal processing circuit 300A. do.

In the display area A1 of the device substrate 100, a plurality of scanning lines 101 are formed in parallel in the X direction, and a plurality of data lines 102 are formed in parallel in the Y direction orthogonal to this. . At each intersection of the scan line 101 and the data line 102, the gate electrode of the thin film transistor (TFT) 103 is connected to the scan line 101, while its source electrode is connected to the data line 102. The drain electrode is connected to the pixel electrode 104. Each pixel is comprised by the common electrode 201 formed in the pixel electrode 104 and the opposing board | substrate 200, and the dispersion system 1 clamped between these electrodes (refer FIG. 2). That is, each pixel is arranged in a matrix shape corresponding to the intersection of the scan line 101 and the data line 102.

In the electrophoretic display panel A, when the scan line signal Yj is activated, the thin film transistor 103 of the j-th scan line 101 to which the scan line signal Yj is supplied is turned on, and the data line signals X1, X2,… , Xn is supplied to the pixel electrode 104. On the other hand, the common voltage is applied to the common electrode 201 of the counter substrate 200 from a power supply circuit (not shown). As a result, a potential difference is generated between the pixel electrode 104 and the common electrode 201, the electrophoretic particles 3 of the dispersion system 1 are moved, and the display of the gradation in accordance with the image data D is performed for each pixel.

Next, the principle of displaying gradation is explained. 4 is a cross-sectional view briefly illustrating a structure of a split cell. In the electrophoretic display of this example, a reset operation is first performed. In this reset operation, the electrophoretic particles 3 are attracted to the pixel electrode 104 side. When the electrophoretic particles 3 that are surely charged are used, a negative voltage is applied to the pixel electrode 104 based on the voltage of the common electrode 201. As a result, the electrophoretic particles 3 are attracted from the pixel electrode 104 as shown in FIG.

Next, as shown in Fig. 4B, a positive voltage having a gray scale to be displayed is applied between the electrodes. In this way, the electrophoretic particles 3 move toward the common electrode 201 in accordance with the electric field. If the potential difference is zero, the electric field does not work, so the electrophoretic particles 3 stop according to the viscous resistance of the dispersion medium 2. In this case, since the moving speed of the electrophoretic particles 3 is determined according to the electric field strength, that is, the applied voltage, the moving distance is determined according to the applied voltage and the application time. Therefore, if the application time is made constant, the position in the thickness direction of the electrophoretic particles 3 can be controlled by adjusting the applied voltage.

Light incident from the common electrode 201 side is reflected by the electrophoretic particles 3, and the reflected light passes through the common electrode 201 to reach the observer's eye. Incident light and reflected light are absorbed by the dispersion medium 2, and the degree of absorption is proportional to the optical path length. Therefore, the gray level perceived by the observer is determined according to the position of the electrophoretic particle (3). When the application time is constant as described above, since the position of the thickness direction of the electrophoretic particle 3 is determined according to the applied voltage, applying a voltage corresponding to the gradation to be displayed enables the desired gradation display.

By the way, the dispersion system 1 includes a plurality of electrophoretic particles (3). Here, if particle characteristics such as electrical characteristics (e.g., charge amount) or mechanical characteristics (e.g., particle diameter, weight) are provided, the moving speeds of all particles are constant, and all electrophoretic particles 3 behave the same. do.

Next, a circuit for driving the scanning line 101 and the data line 102 will be described.

First, the scan line driver circuit 130 includes a shift register, based on the clock signal YCK from the timing generator 400 or its inverted clock signal YCKB, and becomes active at the start of the vertical scan period. The transmission start pulses DY are sequentially shifted to generate scan line signals Y1, Y2, ... Ym. As a result, scan line signals Y1, Y2, ... Ym in which the active period (H level) is sequentially shifted are generated and output to each scan line 101.

Next, the data line driving circuit 140A is supplied with the image data D and reset data Drest from the image signal processing circuit 300A, and receives the X clock signal XCK and the X clock signal from the timing generator 400. The inverted X clock signal XCKB, the X transfer start pulse DX, and the like are supplied to generate data line signals X1, X2, ..., Xn and output them to each data line 102.

Next, the operation outline of the electrophoretic display will be described with reference to the timing chart of FIG. 5.

First, when the power of the electrophoretic display device is turned on from the off state at time t0, power is supplied to the image signal processing circuit 300A, the timing generator 400 and the electrophoretic display panel A. FIG. At a time t1 when a predetermined time has elapsed and the circuit operation is stabilized, the image signal processing circuit 300A outputs reset data Drest for one field period. In this reset period Tr, the electrophoretic particles 3 are attracted to the pixel electrode 104 side as described above, and the spatial state thereof is initialized. The data line driver circuit 140 outputs the reset voltage Vrest corresponding to the data value of the reset data Drest to each data line 102, while the scan line driver circuit 130 outputs each scan line 101. ) Is sequentially selected to supply a voltage to the pixel electrode 104, and a reset voltage Vrest is applied between all the pixel electrodes 104 and the common electrode 201.

Next, when time t2 is reached, recording time Tw is started. In this recording time Tw, the image signal processing circuit 300A outputs image data D over one field period. Each pixel electrode 104 is recorded with a gradation voltage V corresponding to the gradation to be displayed, thereby completing one display screen.

Next, the holding period Th from the time t3 to the time t4 is a period for supporting the image recorded in the immediately preceding recording period Tw, and the length can be arbitrarily set. In this period, the image signal processing circuit 300A stops the operation to output the image data D, and no electric field is generated between the pixel electrode 104 and the common electrode 201. The electrophoretic particles 3 have no change in spatial state without an electric field. Therefore, the still picture is displayed in the period.

Next, time t4 to time t6 is a period for rewriting image data, and the reset operation and the recording operation are performed as in the period from the time t1 to the time t3. As a result, the display screen is updated.

As a result, the pixel electrode 104 is selected by the scan line driver circuit 130 sequentially selecting each scan line 101, and the data line driver circuit 140 is configured to target the selected pixel electrode 104. Through the process as described above it is repeatedly performed to output the positive data or the negative data. Through this process, the gray level to be displayed by the pixel is determined by the sum of the positive data and the negative data supplied to each pixel, and the entire image is determined by the pixels operating in this manner.

However, such a conventional electrophoretic display device and other electrophoretic display devices use a thin film transistor (TFT) as a switching element for transferring data to the pixel electrode, in which case the subsequent panning process There was this difficult issue. That is, the TFT used as the switching element of the electrophoretic display device has a problem in that the manufacturing process is complicated and expensive compared with the TFD (MIM diode).

Accordingly, an object of the present invention is to use a thin film diode (TFD) having a metal-insulating layer-metal structure instead of using a thin film transistor as a switching element for transferring data to a pixel electrode in an electrophoretic display. To perform electrophoretic display.

The present invention for achieving the above object comprises: an image signal processing circuit for correcting an input image signal to output image data, and outputting reset data for the image data; A timing generator for generating various timing signals for controlling a scan line driver circuit or a data line driver circuit in response to the image data output from the image signal processing circuit; A scan line driver circuit for supplying a scan line signal to an electrophoretic material of pixels arranged in a matrix in a display area on an electrophoretic display panel; A data line driver circuit for supplying a data line signal to the electrophoretic material; A common voltage supply unit selectively outputting a common voltage between a high voltage, a low voltage, and a zero voltage applying section to the electrophoretic material under the control of the timing generator; The pixel structure in the form of a matrix is formed by using TD, which is a switching element, and the electrophoretic material as a unit component, and the common corresponding to the image data is applied to the electrophoretic material of the pixel selected by the scan line signal and the data line signal. And a display area of the electrophoretic display panel to determine the gray level at which the pixel is displayed by transferring the voltage.

Another object of the present invention is to select a target pixel on the display area by using a scan line signal output through a scan line driver circuit and a data line signal output through a data line driver circuit; Selectively outputting a common voltage between a high voltage, a low voltage, and a zero voltage application period with respect to the electrophoretic material of the selected pixel; A pixel structure in a matrix form is formed by using TD, which is a switching element, and the electrophoretic material as unit components, and the common voltage corresponding to the image data is transferred to the electrophoretic material of the selected pixel so that the corresponding pixel is displayed. It is characterized in that it comprises a process that allows the gradation to be determined.

The present invention uses the data line signal output through the scan line driver circuit and the data line signal output through the data line driver circuit, and among the pixels arranged in a matrix form on the basis of TDF and electrophoretic material, By selecting a pixel and supplying a positive common voltage, a negative common voltage, or a zero level common voltage to the electrophoretic material of the selected pixel, the gray level to be displayed by the pixel is determined, thereby reducing the process cost. There is an advantage that it can be reduced and used as is without further processing of the EP film.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 6 is a block diagram showing an embodiment of a pixel driving apparatus of an electrophoretic display according to the present invention. As shown therein, the electrical characteristics of the electrophoretic display panel 607 with respect to an input image signal VID And an image signal processing circuit 601 for generating and outputting the image data D, and outputting the reset data Drest for a predetermined period before outputting the image data D. ; A timing generator 602 for generating various timing signals for controlling the scan line driver circuit 603 or the data line driver circuit 604 when the image data D is output from the image signal processing circuit 601; ; A scan line driver circuit 603 for supplying scan line signals Y1, Y2, ... Ym to a plurality of electrophoretic materials 606C arranged in a matrix in the display area 606 on the electrophoretic display panel 607; A data line driver circuit 604 for supplying data line signals X1, X2, ..., Xn to the plurality of electrophoretic materials 606C; A common voltage supply unit 605 for selectively outputting a common voltage between a high voltage application section, a low voltage application section, and a zero voltage application section to the plurality of electrophoretic materials 606C under the control of the timing generator 602; The TFT structure, which is a switching element, and the electrophoretic material 606C form a pixel structure in a matrix form, and the scan line signals Y1, Y2, ... Ym and the data line signals X1, X2, Xn The display area 606 of the electrophoretic display panel 607 in which the common voltage corresponding to the image data is transmitted to the electrophoretic material 606C of the pixel selected by the pixel, so that the gray level to be displayed by the pixel is determined. When configured, the operation of the embodiment of the present invention configured as described in detail as follows.

In order to drive the electrophoretic material 606C arranged in a matrix form in the display area 606 on the electrophoretic display panel 607, the scan line signals Y1, Y2, ... Ym are output through the scan line driver circuit 603. The basic principle of outputting the data line signals X1, X2, ..., Xn through the data line driver circuit 604 is similar to that of a conventional electrophoretic display device.

That is, the image signal processing circuit 601 performs correction processing corresponding to the electrical characteristics of the electrophoretic display panel 607 with respect to the input image signal VID to generate and output the image data D. Before outputting the image data D, the reset data Drest is output for a predetermined period. The reset data Drest is used to attract the electrophoretic particles moving in the dispersion system to the pixel electrode side and to initialize the spatial state.

The timing generator 602 generates various timing signals for controlling the scan line driver circuit 603 or the data line driver circuit 604 when the image data D is output from the image signal processing circuit 601.

The scanning line driver circuit 603 has a shift register and is based on the clock signal YCK or its inverted clock signal YCKB from the timing generator 602 and becomes active at the start of the vertical scanning period. The start pulse DY is shifted sequentially to generate the scan line signals Y1, Y2, ... Ym.

The data line driving circuit 604 receives the image data D and the reset data Drest from the image signal processing circuit 601 and inverts the X clock signal XCK and inverted from the timing generator 602. The X clock signal XCKB, the X transfer start pulse DX, and the like are supplied to generate data line signals X1, X2, ..., Xn, and output them to each data line 606A.

By the way, in the present invention, the data line signals X1, X2 ..., Xn output through the scan line driver circuit 603 and the data line signals X1, X2 ..., Xn output through the data line driver circuit 604. The target pixel is selected from among the pixels arranged in a matrix form based on the TTF and the electrophoretic material 606C. Then, the corresponding pixel is displayed by supplying the positive common voltage or the negative common voltage or the zero level common voltage to the electrophoretic material 606C of the selected pixel corresponding to the image data D. The gradation to be determined is to be determined, which will be described in more detail as follows.

Figure 7 shows the pixel driving timing in the electrophoretic apparatus according to the present invention. The section of the common voltage Vc supplied from the common voltage supply unit 605 to the common electrode is classified into a high voltage Vc_H application section, a low voltage Vc_L application section, and a zero voltage (0V) application section according to the voltage level. do.

In each of the sections according to the combination of the scan line signal (Y) and the data line signal (X), the section (①) to which both the scan line and the data line signal is applied, the section (②) to which only the data line signal is applied, and only the scan line signal is applied. A section ③ may occur.

In the case of a pixel to which both the data line and the scan line signals X and Y are applied (1), the TFT T is turned on by the scan line and the data line signals X and Y, so that the corresponding pixel is shown in FIG. 8A. It can be expressed as an equivalent circuit.

In this case, since both TDFDs are turned on by the potential difference "Vd_H-Vd_L" between the scan line 606B and the data line 606A in the pixel, the two TFTs are turned on both ends of the electrophoretic material 606C. A voltage corresponding to a potential difference between the voltage of the common node Nc of the TFTD and the common voltage Vc supplied from the common voltage supply unit 605 is supplied.

At this time, the voltage VEP = (Vd_H + Vd_L) / 2-Vc supplied to both ends of the electrophoretic material 606C. For example, if Vd_H = 15V, Vd_L = -15V, Vc = 15V, the voltage supplied across the electrophoretic material 606C VEP = (15-15) / 2-15 [V] = -15 [V] Becomes However, (Vd_H-Vd_L)> 2 x Vth_TFD.

The TFT TFD preferably has a metal insulator metal (MIM) structure of a metal, an insulating layer, and a metal.

In the case of a pixel to which the scan line signal Y is not applied and only the data line signal X is applied (②), the potential difference between the scan line 606B and the data line 606A at the pixel is Vd_L, which means It is less than the sum of the threshold voltages of the TFTs. Accordingly, the common node Nc of the two TFTs TDF may be floated to represent the pixel in an equivalent circuit as shown in FIG. 8B.

In this case, the common voltage Vc is not supplied to the electrophoretic material 606C regardless of the level of the common voltage Vc supplied from the common voltage supply unit 605. Therefore, the potential difference due to the common voltage Vc is not formed in the electrophoretic material 606C. However, | Vd_L | <2 x | Vth_TFD |.

In the case of a pixel to which the data line signal X is applied but the scan line signal Y is not applied (③), the potential difference between the scanning line 606B and the data line 606A at that pixel is Vd_H. It is less than the sum of the threshold voltages of the TFTs. Accordingly, the common node Nc of the two TFTDs TDF may be floated to represent the pixel in an equivalent circuit as shown in FIG. 8C.

Even in this case, the common voltage Vc is not supplied to the electrophoretic material 606C regardless of the level of the common voltage Vc supplied from the common voltage supply unit 605. Therefore, the potential difference due to the common voltage Vc is not formed in the electrophoretic material 606C. However, | Vd_H | <2 x | Vth_TFD |.

As a result, in the case of sections ② and ③ of the three sections ①, ②, and ③, the common node Nc of the two TFTDs of the corresponding pixel is floated, and thus the electrophoretic material 606C is not formed. Does not affect However, in the ① section, since both TFTs of the corresponding pixel are turned on, the voltages of the common node Nc of the two TFTs (TFD) are common to both ends of the electrophoretic material 606C. A voltage corresponding to a potential difference between the common voltages Vc supplied from the voltage supply unit 605 is supplied, thereby determining the gray level to be displayed by the pixel.

Therefore, for the target pixel, the pixel is selected by applying both the data line signal X and the scan line signal Y as in the section 1, and the high voltage Vc_H is provided through the common voltage supply unit 605. ) Or low voltage (Vc_L) or zero voltage (0V) is selectively supplied.

The reason for supplying the common voltage in this manner is that the driving method of the electrophoretic device basically uses a PWM (PWM) method. The high voltage Vc_H is a driving voltage of the electrophoretic material 606C, and the low voltage Vc_L is a reverse voltage of the high voltage Vc_H and is a voltage used for initial reset driving or application of a reverse phase signal. The voltage (0V) is a reference voltage used to remove the influence of the parasitic capacitance (C) by supplying 0V across the electrophoretic material (606C).

The driving sequence of the electrophoretic display proceeds from "inverted phase data input of the previous image frame" → "screen reset (B & W)" → "image input of this frame" → "reference potential input". It becomes like 9.

That is, in FIG. 9, the T1 section is a section for inputting reversed phase data of the previous image frame, and the T2 and T3 sections can be repeatedly input as a screen reset section for inputting black and white. The T4 section is a section for inputting image data of this frame, and the T5 section is a zero voltage (0V) application section.

FIG. 10 shows another embodiment of the present invention, in which the scan line signal Y is a negative signal and the data line signal X is a positive signal as in FIG.

Fig. 11 shows the structure of TFTD applied to the present invention by way of example, and is simply manufactured in two to three mask steps, and the number of layers required is smaller than that of the TFT.

12 is a graph showing the transfer characteristics of the TFT D applied to the present invention. This TFT is a switch for transmitting and holding analog data, and when applied to a conventional LCD, there is a problem in expressing a high gradation, but when applied to an electrophoretic display, unlike a LCD, a digital data input method is used. (PWD), so there is no problem in high gradation expression.

In particular, in the case of implementing the electrophoretic display by applying the present invention, there is a big advantage that the manufacturing cost is low, it is advantageous to apply to a portable display device.

1 is an exploded perspective view showing the mechanical configuration of a conventional electrophoretic display panel.

ego,

2 is a partial cross-sectional view of a conventional electrophoretic display panel.

3 is a block diagram of a conventional electrophoretic display.

Figure 4 (a), (b) is an explanatory diagram showing the principle of movement of electrophoretic particles in the divided cell.

5 is a timing diagram showing output data in an image signal processing circuit;

6 is a block diagram of a pixel driving device of an electrophoretic display device according to the present invention;

7 is a pixel driving timing diagram in an electrophoretic apparatus according to the present invention.

8A to 8C are equivalent circuit diagrams of pixels according to a driving mode in the present invention.

9 is a timing diagram showing a driving sequence of an electrophoretic display according to the present invention;

10 is a waveform diagram showing another embodiment of a scan line signal and a data line signal in the present invention;

Figure 11 is a structural diagram of the TFT (TFD) applied to the present invention.

12 is a graph showing the transfer characteristics of the TFT (TFD) applied to the present invention.

*** Description of the symbols for the main parts of the drawings ***

601: image signal processing circuit 602: timing generator

603: scan line driver circuit 604: data line driver circuit

605: common voltage supply unit 606: display area

606A: data line 606B: scan line

606C: Electrophoretic material 607: Electrophoretic display panel

Claims (11)

An image signal processing circuit for correcting an input image signal to output image data, and outputting reset data for the image data; A timing generator for generating and outputting various timing signals for controlling a scan line driver circuit or a data line driver circuit in response to the image data output from the image signal processing circuit; A scan line driver circuit for supplying a scan line signal to the electrophoretic material of each pixel arranged in a matrix in a display area on the electrophoretic display panel; A data line driver circuit for supplying a data line signal to the electrophoretic material; A common voltage supply unit selectively outputting a common voltage between a high voltage, a low voltage, and a zero voltage applying section to the electrophoretic material under the control of the timing generator; The common voltage corresponding to the image data corresponds to the image data on the electrophoretic material of the pixel selected by the TFT and the electrophoretic material as the unit element as a unit component, and the pixel selected by the scan line signal and the data line signal. And a display area of the electrophoretic display panel to determine the gray level to which the corresponding pixel is to be transmitted. The pixel array device of claim 1, wherein each pixel arranged in a matrix form comprises: first and second TFTs each having one side connected to a data line and a scan line and the other side connected to a common node; And an electrophoretic material having one side connected to the common node and the other side connected to an output terminal of the common voltage supply unit. The pixel driving device of claim 1, wherein the scanning line signal is a positive signal and the data line signal is a negative signal. 2. The pixel driving device of claim 1, wherein the scanning line signal is a negative signal and the data line signal is a positive signal. The electrophoretic display of claim 1, wherein the electrophoretic material is configured such that when both the scan line signal and the data line signal are supplied, the scan line and the data line are commonly connected to one side through the first and second TFTs, respectively. Pixel drive of the device. The pixel driving apparatus of claim 1, wherein the electrophoretic material is configured to be in a floating state with the first and second TFTs when one of the scan line signal and the data line signal is not supplied. The pixel driving apparatus of claim 1, wherein the output terminal of the common voltage supply unit is commonly connected to the other side of the electrophoretic material of each pixel arranged in the matrix form. The pixel driving device of claim 1, wherein the zero voltage application period is a reference voltage used to supply 0V across both ends of the electrophoretic material to remove the influence of parasitic capacitance. The pixel driving device of an electrophoretic display of claim 1, wherein the TFT is formed of a metal-insulating layer-metal. A first step of selecting a desired pixel on the display area by using a scan line signal output through the scan line driver circuit and a data line signal output through the data line driver circuit; Selectively outputting a common voltage between a high voltage, a low voltage, and a zero voltage application period with respect to the electrophoretic material of the selected pixel; A pixel structure in a matrix form is formed by using TD, which is a switching element, and the electrophoretic material as unit components, and the common voltage corresponding to the image data is transferred to the electrophoretic material of the selected pixel so that the corresponding pixel is displayed. And a third process of determining a gray level to be determined. 11. The method of claim 10, wherein the scan line signal is a positive signal and the data line signal is a negative signal, or the scan line signal is a negative signal and the data line signal is a positive signal. .

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