JP2005189851A - Display apparatus and pen input unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable high voltage drive when a high speed response is required and to make a mounting scale small and to attain cost reduction. <P>SOLUTION: An electrophoretic display apparatus includes a display panel 10 including gate line electrodes 33 and source line electrodes 34 arranged in a matrix to provide a number of pixels at respective intersections of these electrodes, a gate line drive circuit 213 for driving the gate line electrodes 33, and a source line drive circuit 212 for driving the source line electrodes 34. When a display state of the display panel 10 is partially rewritten, a reference voltage of a common electrode 37 is switched to a negative voltage Vcom on the basis of 0 V which is a reference voltage at the time of multi-gradation level display. As a result, the display apparatus can be driven at a higher voltage Vp than the maximum driving voltage Vwmax at the time of multi-gradation level display of the display panel 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a display device including a display panel having a large number of pixels arranged in a matrix and a pen input device.

  With the development of information equipment, the need for low power consumption and thin display devices is increasing, and research and development of display devices that meet these needs are actively conducted.

  In particular, since it is often used outdoors for applications such as wearable PCs and electronic notebooks, and it is desired to save power and save space, for example, display functions and coordinate input processing using a thin display such as a liquid crystal display are integrated. Devices that can be directly input by pressing the content displayed on the display with a pen or a finger have been commercialized.

  However, since many liquid crystals do not have so-called memory properties, it is necessary to continue voltage application to the liquid crystals during the display period. On the other hand, a liquid crystal having a memory property is difficult to ensure reliability when assumed to be used in various environments such as a wearable PC, and has not yet been put into practical use.

  Therefore, an electrophoretic display device has been proposed as one of thin and light display systems having memory characteristics.

  This type of electrophoretic display device includes a pair of substrates arranged with a predetermined gap therebetween, an insulating liquid filled between these substrates, and a large number of colored electrifications dispersed in the insulating liquid. Electrophoretic particles and display electrodes arranged on each pixel along each substrate are provided (for example, refer to Patent Document 1).

  In this apparatus, since the colored charged electrophoretic particles are charged positively or negatively, the colored charged electrophoretic particles are adsorbed to any one of the display electrodes according to the polarity of the voltage applied to the display electrode. It is possible to display various images by controlling the state where the colored particles are adsorbed and the colored particles are adsorbed on the lower electrode and the state where the color of the insulating liquid is visible by controlling the applied voltage. This type of device is referred to as a “up and down movement type”.

  Further, as another example of the conventional electrophoretic display device, the first electrode (common electrode) is arranged along the inter-pixel shielding layer instead of being arranged so as to sandwich the insulating liquid as in the type described above. Similarly, the second electrode (pixel electrode) is disposed on the entire pixel display portion to reflect incident light and is covered with an insulating film (for example, see Patent Document 2).

  For this reason, the insulating liquid only needs to be transparent, and the second electrode is covered with the electrophoretic particles to perform black display, and the electrophoretic particles are collected on the first electrode between the pixels. The second electrode is exposed to display white. Thus, an image can be displayed by controlling the polarity of the applied voltage for each pixel.

  Further, by combining these display devices with a so-called resistive film type coordinate position detection device (digitizer) (see, for example, Patent Document 3), it is possible to perform input by pen input or finger pressure sensing, and with low power consumption. A space-saving wearable PC or a display device such as paper that can take notes can be realized.

US Pat. No. 3,612,758 JP 9-2111499 A JP-A-5-324163

  However, the above-described conventional electrophoretic display device generally has a slow response speed. For this reason, for example, when a high-speed response such as pen input is required, the slow response speed makes the user feel uncomfortable. End up.

  In order to solve this inconvenience, it is conceivable to drive the above-described electrophoretic display device with a high voltage. However, when simply driving at a high voltage, for example, a high-voltage driver IC is provided, It is conceivable to have a high breakdown voltage TFT (Thin Film Transistor). However, the high withstand voltage driver IC and the high withstand voltage TFT described above have a problem of increasing the mounting scale and cost.

  The present invention has been made to solve the above-described problems, and enables a high-voltage drive while suppressing an increase in mounting scale and cost, thereby providing a display device and a pen input device having high-speed display response. provide.

The present invention firstly provides a display device comprising:
A display panel in which pixels are arranged in a matrix,
A common electrode provided in common with the pixel electrode provided in each of the pixels,
A scanning line and a signal line for supplying a voltage to the pixel electrode;
A driving circuit connected to the common electrode and the scanning line and the signal line; and a control circuit for supplying a signal to the driving circuit.
Because
The driving circuit selects and scans the scanning lines sequentially, and applies a variable voltage to the pixels through the signal lines, thereby selecting a driving mode for displaying a gradation image on the display panel, and the driving circuit selects The control circuit selects and switches the drive mode in which the partial pixels are rewritten to black or white by applying a voltage higher than the voltage variable range to the partial pixels on the scanning line. To do.

  In the driving mode in which a part of the pixels of the display panel is rewritten, it is preferable that the driving circuit selects and scans only a part of the scanning lines.

A more preferable form of the display device is:
In a driving mode for displaying a gray scale image on the display panel, the driving circuit supplies a variable voltage to the pixel electrode and supplies a reference voltage to the common electrode to rewrite some pixels of the display panel. The driving circuit supplies the maximum voltage of the variable voltages to the pixel electrode of the pixel to be rewritten, sets the pixel electrode of the pixel that is not to be rewritten to high impedance, and uses the reference voltage to rewrite the pixel electrode to the common electrode. A voltage shifted to the opposite polarity side with respect to the voltage supplied to is supplied.

  The display device further includes an external input device, and when the display device receives display information from other than the external input device, the control circuit selects a drive mode for displaying the gradation image and displays the display information. When the display circuit receives display information from the external input device and the display device receives display information from the external input device, the control circuit selects a drive mode for rewriting a part of the pixels of the display panel and receives from the external input device. The displayed information may be displayed on the display panel.

  The external input device may be a position information input device arranged on the display panel, and the external input device may be a pen input device or a handwriting input device.

The present invention also includes a pen input device having:
A display panel in which pixels are arranged in a matrix,
A common electrode provided in common with the pixel electrode provided in each of the pixels,
A scanning line and a signal line for supplying a voltage to the pixel electrode;
A driving circuit connected to the common electrode and the scanning line and the signal line;
A control circuit for supplying a signal to the drive circuit; and a position detector for detecting a position designated by a pen and outputting the detected position to the control circuit.
Because
When there is no output from the position detector, the control circuit selects a driving mode for displaying a gradation image on the display panel, and the driving circuit applies a variable voltage to the pixel through the scanning line and the signal line. By displaying a gradation image on the display panel,
When there is an output from the position detector, the control circuit selects a driving mode in which some pixels of the display panel are rewritten to black or white, and the driving circuit scans a part of the scanning lines to form some pixels. By applying a voltage higher than the variable range of the voltage, the pixel of the display panel corresponding to the position designated by the pen is rewritten to black or white.

  According to the present invention, when the display state on the display panel is rewritten with binary gradation representation, high-speed response is possible by driving at a voltage higher than the maximum drive voltage at the time of multi-gradation display. In addition, it is possible to reduce the mounting scale and cost of the peripheral circuit.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  First, a first embodiment of the present invention will be described.

  FIG. 2 is a block diagram illustrating a system having a still image display, pen input function, and display function.

  The display device system includes a display panel 215 including an electrophoretic display element, a display panel 10 in which a TFT substrate (TFT Backplane) 214 is stacked, a source line driving circuit 212 for driving a matrix, and gate lines. A display module 217 including a drive circuit 213, a common electrode drive circuit 216, a display control module 218, a video RAM (hereinafter referred to as “VRAM”) 211 as an image memory for display, a CPU 28, and a peripheral memory circuit (Flash ROM) 29 And a memory circuit (SDRAM) 210.

  An external input device (sensing device) 27 is connected to the display control module 218. Here, the external input device 27 is a device for inputting position information, and a pen input device is a typical one.

  The CPU 28 supplies control signals to the display control module 218 and peripheral memory circuits 29 and 210.

  The graphic controller (Graphic Controller) 21 controls information stored in advance in an internal memory (a memory 29 constituted by a flash ROM, a memory 210 constituted by an SDRAM) and data input / output with an external memory (not shown). An external memory control circuit 25, a communication means (external I / F) 24 for performing data input / output through a line connected to the outside, or a digitizer controller 23 for controlling a pen input tablet which is an external input device 27, Capture image information through

  Further, the graphic controller 21 draws information to be displayed on the display unit 215 of the display panel 10 on the VRAM 211 based on the captured image information, and displays image data and control signals on the panel controller (based on the information on the VRAM 211. The data is transferred to the display module 217 via the panel controller 22. Further, necessary control signals such as a scanning selection signal for selecting and scanning the gate line, an image information signal to be sent to the source line driving circuit, and a Vsync and Hsync signal for giving the transfer timing are generated and sent to the panel controller 22.

  The panel controller 22 sends these control signals to the drive circuits for the gate lines, source lines, and common electrodes of the display panel. Power is supplied to each circuit block through power management 26.

  The display module 217 receives the image data output from the panel controller 22 and a timing control signal such as Vsync, Hsync, and the like, and the display panel 10 having the TFT backplane 214 and the display unit 215 receives the gate line driving circuit 213 and the source. A desired voltage is applied to the TFT backplane 214 from the line driver circuit 212 and the common electrode driver circuit 216, and gradation display is performed by changing the migration state of the particles in each pixel of the display unit 215.

  As will be described in detail later, this display device has two display modes, a gradation display mode and a binary display mode, and the binary display mode is used for pen input. Therefore, the above-described source line driver circuit 212 has an output stage that can select high impedance.

  Hereinafter, the display device will be described as an electrophoretic display device, but the present invention may be a liquid crystal display device as long as the display device can be driven by voltage. It is preferable that the applied voltage can be varied to display a multi-tone intermediate state. After writing, the present invention can also be applied to a device having a so-called memory property in which a written display state is maintained without applying a voltage to the pixel.

  FIG. 3 is a schematic view of a part of a 300 × 250 column TFT active matrix array in the present embodiment. In the figure, the display panel 10 described above has a gate line electrode 33 as a scanning electrode and a source line electrode 34 as an information electrode arranged in a matrix, and the gate line electrode 33 and the source line electrode 34 are arranged. Many pixels are formed at each intersection position. The display panel 10 includes a TFT (Thin Film Transistor) 35, a pixel electrode 36, and a common electrode (COM) 37. The display panel 10 includes a gate line driving circuit 213 that drives the gate line electrode 33. And a source line driving circuit 212 for driving the source line electrode 34 is connected. In the present embodiment, the gate line drive voltage has an on voltage of +20 V, an off voltage of -20 V, and a frame rate of 15 Hz. The source line drive voltage Vw is 0V to 15V, and the drive voltage Vcom of the common electrode is 30 to -15V.

  FIG. 4 is a schematic diagram of one pixel portion of the electrophoretic display device in this embodiment. In the figure, black electrophoretic particles 63 are negatively charged. For example, when the first electrode 37 is a common electrode and the second electrode 36 is a pixel electrode, the pixel electrode is compared with the common electrode 37. When a positive voltage is applied to the pixel electrode 36, as shown in FIG. 4A, the pixel electrode 36 is covered with black electrophoretic particles 63 so that a black display state is obtained, and the pixel electrode 36 is negative with respect to the common electrode 37. When a voltage is applied, as shown in FIG. 4B, the black electrophoretic particles 63 are collected on the common electrode 37 between the pixels to expose the pixel electrode 36 and enter a white display state.

  Next, FIG. 5A shows the voltage-optical response (reflectance) characteristics of the pixel in this embodiment. That is, the voltage-optical response (reflectance) characteristic from the white state in the initial state is white at 0 V or less as shown by the solid line, and is black at 15 V or more. The voltage-optical response (reflectance) characteristics from the black state in the initial state are indicated by broken lines. FIG. 5B shows the voltage-response time characteristics of the pixel in this embodiment. Here, the response time is the time required for the response to be completed from the white state to the black state. As shown in the figure, it can be understood that the response characteristic improves as the applied voltage increases. Note that when performing 16 gradation display, gradation control is performed within the source line drive voltage range (0 to 15 V) after all pixels are aligned in a white state. At this time, Vcom is 0 V (ground voltage).

  As described above, the external input device 27 is connected to the display device. Here, as described above, the external input device 27 is a device for inputting position information, and a pen input device is a typical one. The position indicated by the pen is detected and output as digital information. The pen input device may consist of a pen and a dedicated tablet, but is made of transparent material and placed on the display panel, overwriting the image on the display panel with the pen, or scanning on the screen with the pen The pointing device may be used as a pointing device for performing the above. In the stacked configuration, the display panel is required to be able to display line drawings such as handwritten characters input with a pen without delay.

  Here, when considering a pen input from a pen input tablet 27 which is an example of the external input device 27, when a position on the tablet is indicated by a pen and input is performed, the screen displayed so far is displayed. On the other hand, it is assumed that additional writing will be performed. In this case, it is only necessary to rewrite the display only for the part written with the pen. In other words, the part other than the part written with the pen can be held as it is.

  When no pen input is made, since there is no output from the pen input tablet 27, the digitizer control unit 23 transmits the information to the graphic controller 21. The graphic controller 21 is in the normal display mode, that is, in the internal memories 29 and 210. The mode for displaying the image information and the external image information received through the communication means 24 is selected. At this time, the gate line driving circuit 213 sequentially selects and scans the gate lines of the display panel. A gradation signal voltage corresponding to image information, that is, a variable voltage in the range of 0 to 15 V on the black side and a range of 0 to −15 V on the white side as shown in FIG. 5 is supplied. A reference voltage is supplied from the common electrode driving circuit 216. These are applied to the TFT substrate 214, and gradation display is performed by changing the migration state of the particles in each pixel of the display unit 215.

  When pen input is performed, position information corresponding to the position instructed by the pen is sent from the pen input tablet 27 to the graphic controller 21 through the digitizer control unit 24 and written in the VRAM 211 as a display memory. At this time, a flag is set in the VRAM address of the written pixel to indicate that pen input has been performed.

  The graphic controller 21 sends the image information in the display memory to the display panel 10, but when the flag is set, the graphic controller 21 switches to a drive mode in which scanning lines including that portion are preferentially scanned. In this mode, the operation of rewriting only the pen writing part is performed by the graphic controller 21 scanning only a part of the gate line of the display panel 10 where the rewriting has occurred. At this time, a black signal is sent to the source line of the pixel to be rewritten, and at the same time, the source line of the pixel holding display is set to a high impedance state. Detailed write operation will be described later.

  Hereinafter, such a driving method for pen input is referred to as partial rewriting. In partial rewriting, even in a display panel having a large number of scanning lines, that is, a number of gate lines, the number of gate lines to be rewritten is smaller than that, so that the time required for rewriting by partial scanning can be shortened. In the pen input device, in order not to give a sense of incongruity to the user, it is necessary to display the trajectory of the input pen immediately on the screen, but this can be achieved by partial rewriting.

  Furthermore, when writing handwritten characters on the screen by pen input, it is only necessary to draw a black line on a white background, so that the pixels need only be rewritten to a black state, and halftone display is not required. The display device of the present embodiment provides high-speed responsiveness in such a partial rewriting operation that performs only black display.

  Next, high voltage driving in partial rewriting binary driving will be described.

  In order to explain the high voltage driving in the partial rewrite binary driving, consider the pixels “A” and “I” in FIG. In this case, it is assumed that pen input is performed on the pixels at the intersections of s1 · g1 (“a”), s2 · g2, and s3 · g3 in FIG. 3, and “a” is a pixel to be rewritten. , “I” is a pixel that is held as it is. As pre-writing, control to a desired gradation level (the reflectance of the pixel “A” is R1 and the reflectance of the pixel “A” is R2) is finished, and the optical response is kept constant. And

  FIG. 1 shows a driving waveform for the pixels “A” and “I” and a timing chart of the optical responses of the pixels “A” and “I”. 1A is a voltage waveform applied to the gate electrode g1 in FIG. 3, FIG. 1B is a voltage waveform applied to the source electrode s1 in FIG. 3, and FIG. 1C is a source electrode in FIG. The applied voltage waveform to s2 is shown, and FIG. 1D shows the applied voltage waveform to the common electrode in FIG. FIG. 1E shows the waveform of the inter-electrode voltage (potential difference between the pixel electrode 36 and the common electrode 37) of the pixel “A” in FIG. 3, and FIG. 1F shows the waveform of the pixel “A” in FIG. The electrode voltage waveform is shown. Further, FIG. 1G shows the optical response of the pixel “A” in FIG. 3, and FIG. 1H shows the optical response of the pixel “A” in FIG.

  First, the pixel “A” (pixel to be rewritten) will be described. The interelectrode voltage Vp of the pixel “A” shown in FIG. 1E is the difference between the source electrode s1 voltage Vwmax and the common electrode voltage Vcom in the time period t1 when the gate electrode g1 is turned on, Vp = Vwmax−Vcom, Become. Here, Vwmax sets the maximum voltage (15V) that can be output from the source line driver circuit. At this time, the common electrode voltage Vcom is set to -15V (0V in normal multi-tone driving). Therefore, it is possible to apply a voltage that is larger by Vcom (−15 V) than that in normal multi-gradation driving. Accordingly, high voltage driving is possible, and the response of the pixel “A” is completed in a short time.

  Next, the pixel “A” (the pixel to be held as it is) will be described. Normally, the inter-electrode voltage of the pixel “a” shown in FIG. 1F is the difference between the voltage of the source electrode s2 and the voltage of the common electrode in the time period t1 when the gate electrode g1 is turned on. In this case, as shown in FIG. 1C, the source electrode s2 is in a high impedance state. Therefore, there is no potential difference between the pixel electrode and the common electrode in the pixel “A”. Therefore, regardless of the value of Vcom, the inter-electrode voltage of the pixel “a” does not change. That is, in this case, it is possible to keep the pixel of “A” as it is.

  After writing black with respect to the scanning line g1 as described above, the scanning line g2 is selected at time t2 and a voltage is applied in the same manner, and only the selected scanning lines are scanned in the following order.

  As described above, high voltage driving in partial rewriting binary driving is realized. When this driving is performed, the entire surface may of course be scanned, but a high-speed display response can be achieved by scanning only the scanning line including the pixel to be rewritten. According to this embodiment, the response performance of a display element with a slow response speed is improved, and a stress-free pen input can be performed.

  Next, a second embodiment of the present invention will be described.

  In this embodiment, the display device of the present invention is applied to white and black binary display. In the present embodiment, the same display device as that in the first embodiment described above is used.

  In a pen input device, a function such as erasing an erroneously input line or drawing a pen trajectory by inverting the black and white of the line even in a black background portion is required. In this case, in addition to the black writing described in the first embodiment, it is necessary to write white to the pixels. When a part of the image displayed on the screen is moved by dragging the pen, white is written as a background screen in the pixel after the image has moved. The display device of the present embodiment performs such a display response at high speed when performing binary display of white and black. Thereby, it is also possible to display a binary display moving image.

  In order to explain the display by binary gradation expression, consider the pixels “a” and “a” in FIG. In this case, black is displayed for pixels at the intersections of s1 · g1 (“a”), s2 · g2, and s3 · g3 in FIG. 3, and other pixels including “A” are displayed. White shall be displayed. In addition, the optical response is kept constant for the pixels for which control to the desired gradation level has been completed.

  FIG. 6 shows a drive waveform for the pixels “A” and “I” and a timing chart of the optical responses of the pixels “A” and “I”. 6A is a voltage waveform applied to the gate electrode g1 in FIG. 3, FIG. 6B is a voltage waveform applied to the source electrode s1 in FIG. 3, and FIG. 6C is a voltage applied to the source electrode s2 in FIG. The applied voltage waveform is shown, and FIG. 6D shows the applied voltage waveform to the common electrode in FIG. FIG. 6E shows the inter-electrode voltage waveform of the pixel “A” in FIG. 3, and FIG. 6F shows the inter-electrode voltage waveform of the pixel “A” in FIG. Further, FIG. 6G shows the optical response of the pixel “A” in FIG. 3, and FIG. 6H shows the optical response of the pixel “A” in FIG. As shown in the figure, when displaying a moving picture in black and white binary, it is assumed that the image is one frame by two fields. Hereinafter, the driving method will be described in detail.

  First, field 1 will be described.

  The “A” pixel (pixel displaying black) will be described. The inter-electrode voltage Vblack of the pixel “A” shown in FIG. 6E is the difference between the voltage Vwmax of the source electrode s1 and the voltage Vcom1 of the common electrode Vblack = Vwmax−Vcom1 in the time period T11 when the gate electrode g1 is turned on. It becomes. Here, Vwmax sets the maximum voltage (15V) that can be output from the source driver. Therefore, it is possible to apply a voltage that is larger by Vcom1 (−15 V) than during normal multi-tone drive. Accordingly, high voltage driving is possible, and the response of the pixel “A” is completed in a short time.

  The pixel “A” (pixel displaying white) will be described. Normally, the inter-electrode voltage of the pixel “a” shown in FIG. 6F is the difference between the voltage of the source electrode s2 and the voltage of the common electrode in the time period T11 when the gate electrode g1 is turned on. As shown in FIG. 6C, the source electrode s2 is in a high impedance state. Therefore, there is no potential difference between the pixel electrode and the common electrode in the pixel “A”. Therefore, regardless of the value of Vcom, the inter-electrode voltage of the pixel “a” does not change. That is, in this case, the pixel of “I” is kept as it is.

  Next, field 2 will be described.

  The “A” pixel (pixel displaying black) will be described. As shown in FIG. 6B, the source electrode s1 in the time zone T21 when the gate electrode g1 is ON is in a high impedance state. Accordingly, there is no potential difference between the pixel electrode and the common electrode in the pixel “A”. Therefore, regardless of the value of Vcom, the inter-electrode voltage of the pixel “a” does not change. That is, in this case, the pixel “A” continues to hold the black state.

  The pixel “A” (pixel displaying white) will be described. The interelectrode voltage Vwhite of the pixel “a” shown in FIG. 6F is the difference between the voltage Vwmin of the source electrode s2 and the voltage Vcom2 of the common electrode Vwhite = Vwmin−Vcom2 in the time period T21 when the gate electrode g1 is turned on. It becomes. Here, Vwmin sets the minimum voltage (0 V) that can be output from the source driver. Therefore, it is possible to apply a voltage that is larger by Vcom2 (30 V) than in the normal multi-gradation driving. Accordingly, high voltage driving is possible, and the response of the pixel “a” is completed in a short time.

  As described above, the response performance of the display element having a slow response speed is improved, and a good moving image display can be performed.

  Next, a third embodiment of the present invention will be described.

  In this embodiment, there are two modes, a 16 gradation display mode and a binary display mode, and the binary display mode is used for pen input. The source line drive circuit has a D / A converter output stage and an output stage that can select an analog switch output stage, and uses the analog switch output stage in the binary display mode. In this embodiment, the same display device as that of the first embodiment is used except for the source line driver circuit.

  In the case of the 16 gradation display mode, the D / A converter output stage is used, and the maximum value of the drive voltage is 15V and the minimum value is 0V. On the other hand, when performing binary display, an analog switch output stage is used, and by switching, it is possible to select ON: 30 V, OFF: 0 V.

  In order to explain pen input in the binary display mode, consider the pixels “a” and “a” in FIG. In this case, black is displayed for pixels at the intersections of s1 · g1 (“a”), s2 · g2, and s3 · g3 in FIG. 3, and for other pixels including “a”. White shall be displayed. In addition, the optical response is kept constant for the pixels for which control to the desired gradation level has been completed.

  In the case of pen input in which control to a desired gradation level has been completed, for example, in the analog switch mode, the ON voltage (30 V) is applied to the source electrode of the pixel “A” and the OFF is applied to the source electrode of the pixel “A”. A voltage (0 V) is applied. A voltage higher by 15V than the 16 gradation display mode can be applied to the pixel “A”, and the response of the pixel “A” is completed in a short time. Although “0” is applied to the pixel “A”, its optical response level is kept constant due to the retention characteristics of the electrophoretic display element.

  As described above, the response performance of a display element with a slow response speed is improved, and stress-free pen input can be performed. Further, in the case of pen input, by using an analog switch output stage, it can be realized with a smaller circuit scale than a circuit in which a voltage of the same level is driven by a D / A converter.

  In the above description, the electrophoretic display device has been described as an example for explaining the first to third embodiments. However, the present invention is not limited to this. For example, a display device such as a polymer network liquid crystal or a ferroelectric liquid crystal is used. It can also be applied to. Furthermore, the first to third embodiments can be applied to both a vertical movement type electrophoretic display device and a horizontal movement type electrophoretic display device. The electrophoretic particles and the dispersion medium may be encapsulated in each of a large number of microcapsules.

It is a figure which shows the timing chart of various signal waveforms and optical response in the display apparatus which concerns on the 1st Embodiment of this invention. It is a system block diagram same as the above. It is a schematic diagram which shows a TFT backplane same as the above. It is a schematic diagram of one pixel part using the electrophoretic particle same as the above. It is a characteristic view which shows the voltage-optical response characteristic of the pixel of this Embodiment. It is a figure which shows the timing chart of various signal waveforms and optical response in the display apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display panel 21 Graphic controller 22 Panel controller 23 Digitizer controller 24 Interface 25 External memory control circuit 26 Power management 27 Coordinate position detection apparatus (digitizer)
28 CPU
29 Internal memory (FlashROM)
210 Internal memory (SDRAM)
211 VRAM (SDRAM)
212 Source line driving circuit 213 Gate line driving circuit 214 TFT backplane 215 Display unit 216 Common electrode driving circuit 217 Display module 33 Gate line electrode 34 Source line electrode 35 TFT
36 pixel electrode 37 common (COM) electrode 61 first electrode 62 second electrode 63 electrophoretic particles

Claims (9)

A display panel in which pixels are arranged in a matrix, a common electrode provided in common with a pixel electrode provided in each of the pixels, a scanning line and a signal line for supplying a voltage to the pixel electrode, the common electrode, and the scanning line And a drive circuit connected to the signal line, and a display device having a control circuit for giving a signal to the drive circuit,
The driving circuit selects and scans the scanning lines sequentially, and applies a variable voltage to the pixels through the signal lines, thereby selecting a driving mode for displaying a gradation image on the display panel, and the driving circuit selects The control circuit selects and switches the drive mode in which the partial pixels are rewritten to black or white by applying a voltage higher than the voltage variable range to the partial pixels on the scanning line. Display device.   The display device according to claim 1, wherein in the driving mode in which a part of pixels of the display panel is rewritten, the driving circuit selects and scans only a part of scanning lines. In the driving mode for displaying a gradation image on the display panel, the driving circuit supplies a variable voltage to the pixel electrode and a reference voltage to the common electrode,
In the drive mode in which a part of the pixels of the display panel is rewritten, the drive circuit supplies the maximum voltage among the variable voltages to the pixel electrode of the pixel to be rewritten, and sets the pixel electrode of the pixel not to be rewritten to high impedance, 3. The display device according to claim 1, wherein a voltage shifted to a reverse polarity side with respect to a voltage supplied to the pixel electrode to be rewritten from the reference voltage is supplied to the common electrode.   The display device further includes an external input device, and when the display device receives display information from other than the external input device, the control circuit selects a drive mode for displaying the gradation image and displays the display information. When the display circuit receives display information from the external input device and the display device receives display information from the external input device, the control circuit selects a drive mode for rewriting a part of the pixels of the display panel and receives from the external input device. 4. The display device according to claim 1, wherein the display information is displayed on the display panel.   The display device according to claim 4, wherein the external input device is a position information input device arranged to overlap the display panel.   The display device according to claim 4, wherein the external input device is a pen input device or a handwriting input device.   The display device according to claim 1, wherein the display device is an electrophoretic display device.   The display device according to claim 1, wherein the display device is a liquid crystal display device. A display panel in which pixels are arranged in a matrix, a common electrode provided in common with a pixel electrode provided in each of the pixels, a scanning line and a signal line for supplying a voltage to the pixel electrode, the common electrode, and the scanning line A pen input device having a drive circuit connected to the signal line, a control circuit for giving a signal to the drive circuit, and a position detector for detecting a position designated by the pen and outputting the position to the control circuit,
When there is no output from the position detector, the control circuit selects a driving mode for displaying a gradation image on the display panel, and the driving circuit applies a variable voltage to the pixel through the scanning line and the signal line. Thus, when the gradation image is displayed on the display panel and the output of the position detector is present, the control circuit selects a drive mode in which some pixels of the display panel are rewritten to black or white, and the drive circuit Rewriting the pixels of the display panel corresponding to the position indicated by the pen to black or white by scanning a part of the scanning line and applying a voltage higher than the variable range of the voltage to some pixels. A pen input device.

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