Method and circuit for driving electrophoretic display, electrophoretic display and electronic device using same

• US 20020005832A1
• Filed: 06/20/2001
• Published: 01/17/2002
• Est. Priority Date: 06/22/2000
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Katase, Makoto
• Granted Patent: US 6,762,744 B2
• Time in Patent Office: Days
• US Class Current: 345/107
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2310/0205 Simultaneous scanning of several lines in flat panels
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2310/062 Waveforms for resetting a plurality of scan lines at a time
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167

Abstract

A method for driving an active matrix electrophoretic display is provided. In a resetting period Tr, reset data Drest is supplied to a data line drive circuit and a reset voltage is applied to each pixel electrode. Next in a writing period, an image data is supplied to a data line drive circuit and a gradation voltage is applied to each pixel electrode. Subsequently a common voltage is applied to it, in order to take charge which is accumulated between the electrodes away, applying no electric field to a dispersal system. Then a displayed image is held.

Claims

1. A display comprising a common electrode, a plurality of pixels and a plurality of switching elements, with one of each of said switching elements being assigned to a corresponding one of said pixels, and each of said pixels comprising:

a pixel electrode connected to one of said switching elements, and provided in spaced opposing relation to said common electrode; and

a dispersal system comprising a colored fluid in which pigment particles are suspended, said dispersal system being provided between said common electrode and one of said pixel electrodes; and

the method comprising;

a.) applying a 1st voltage to said common electrode;

b.) applying a 2nd voltage to one of said pixel electrodes via a corresponding one of said attached switching elements, to generate an electrostatic field in said dispersal system, to cause said pigment particles to migrate in the direction of the thus generated field to a position corresponding to a color gradation desired for a pixel; and

c.) applying said 1st voltage via a corresponding said switching element to said pixel electrode, to cancel the electrostatic field and fix said pigment particles in a desired position.

2. The method of claim 1,

wherein a reset voltage corresponding to a gradation to be displayed is applied to said 2nd electrode to cause said pigment particles to migrate to an initial position.

3. The method of claim 1, wherein after application of said reset voltage to said second electrode, a brake voltage is applied to said second electrode to halt rapidly the movement of said pigment particles.

4. The method of claim 1,

wherein when an image displayed is to be switched;

a differential voltage, which is a difference between a voltage corresponding to a color gradation displayed previously and that to be displayed, as a 2nd voltage is applied both before and after switching said image.

5. A method for driving an electrophoretic display, the display comprising:

a plurality of data lines;

a plurality of scanning lines, each of which intersects said data lines;

a common electrode;

a plurality of pixel electrodes, with one of said plurality of pixel electrodes being provided at one of each of said intersections of said data lines and said scanning lines, each of said pixel electrodes being provided in opposing spaced relation to said common electrode;

a plurality of dispersal systems comprising a colored fluid in which pigment particles are suspended, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and

a plurality of switching elements, with one of each of said switching elements being provided at a corresponding one of each of said intersections of said data lines and said scanning lines, with an on/off control terminal being connected to one of said scanning lines passing through one of said intersections; and

with one of said data lines passing through one of said intersections, being connected to one of said pixel electrodes provided at each of one said intersections; and

the method comprising;

controlling an image displayed by employing said scanning lines and said data lines, each of said voltages being applied within a set period of one scanning field, in which all of said scanning lines are once scanned; and

within a said set period of scanning field;

applying a common voltage to a said pixel electrode;

selecting said scanning lines sequentially;

applying a voltage to a selected scanning line, to turn on all switching elements connected to the said sequentially selected scanning line;

applying a plurality of pixel voltages to a plurality of said data lines for a set time, to generate electrostatic fields to cause pigment particles to migrate to positions corresponding to desired color gradations of an image displayed; and

applying a voltage to said sequentially selected scanning line, to turn off all of said switching elements connected to said sequentially selected scanning line.

6. The method of claim 5, comprising:

applying said 1^st voltage during a first period of a scanning field;

applying said reset voltage during a next and different scanning field;

applying each of said voltages alternately;

in said first period;

applying a plurality of voltages to said plurality of data lines, to create an

electrostatic field in each of said dispersal systems, to initialize said pigment particles; and

in said next period;

when applying said 1^st voltage, applying a plurality of voltages for obtaining a desired color gradations corresponding to desired color gradations to said selected data lines

7. The method of claim 6,

when a displayed image is switched;

applying said 1^st voltage and said reset voltage to only those pixel electrodes corresponding to pixels the color gradation of which changes following switching of an image displayed.

8. The method of claim 7, further comprising:

selecting a plurality of said scanning lines simultaneously; and

applying said reset voltage to a plurality of said data lines, so that said reset voltage is applied simultaneously to said plurality of pixel electrodes to initialize said pigment particles, .

9. The method of claim 5, further comprising:

applying a plurality of brake voltages to said data lines, to create electrostatic fields, to halt rapidly said pigment particles, after applying said pixel voltages to said data lines.

10. The method of claim 5, further comprising:

applying said reset voltages during a previous said period of a scanning field;

applying a differential voltage to said pixel electrodes during a said period;

in a said set period for applying said reset voltage;

applying a plurality of voltages to the pixel electrodes, to initialize the pigment particles; and

in said set period for applying said pixel voltage;

applying a differential voltage to the data lines, which voltage corresponds to a difference between a voltage corresponding to a color gradation displayed in a previous voltage applying operation, and a next color gradation to be displayed.

11. The method of claim 9, further comprising:

applying said brake voltages to said data lines, to create electrostatic fields to halt rapidly said pigment particles, after applying said pixel voltages to said data lines.

12. The method for driving an electrophoretic display, the display comprising:

a plurality of data lines;

a plurality of scanning lines, each of which intersects said data lines;

a common electrode;

a plurality of pixel electrodes, provided at each intersection of said data lines and said scanning lines, each of said pixel electrodes being provided in opposing spaced relation to said common electrode;

a plurality of dispersal systems, comprising a colored fluid in which pigment particles are suspended, with each of said dispersal systems being provided between said common electrode; and

a plurality of switching elements, with one of each of said switching elements being provided at a corresponding one of each of said intersections of said data lines and said scanning lines, with an on/off control terminal being connected to one of said scanning lines passing through one of said intersections; and

with one of said data lines passing through one of said intersections, being connected to one of said pixel electrodes provided at each of one said intersections; and

the method comprising;

controlling an image displayed by employing said scanning lines and said data lines, each of said voltages being applied within a set period of one scanning field, in which all of said scanning lines are once scanned; and

applying a voltage for resetting said pigment particles in a said first period;

applying a voltage for obtaining a desired color gradation in a said second period;

applying a voltage for holding images displayed in a said third period;

in said first period;

applying a common voltage to a said pixel electrodes;

selecting sequentially said scanning lines;

applying a voltage to a said sequentially selected scanning line, to turn on all switching elements connected to the said sequentially selected scanning line;

applying a plurality of pixel voltages to a plurality of said data lines for a set time, to create electrostatic fields, to initialize said pigment particles in each of said dispersal systems; and

applying a voltage to the scanning line selected, in order to turn off all the switching elements connected to the relevant scanning lines; and

in said second period;

applying said common voltage to said common electrode;

selecting said scanning lines sequentially;

applying a voltage to said sequentially selected scanning lines, to turn on all of said switching elements connected to said sequentially selected scanning lines;

applying a plurality of voltages to said data lines;

applying a plurality of voltages to said sequentially selected scanning lines, to turn off all of said switching elements connected to said sequentially selected scanning lines; and

in said third period;

applying the common voltage to the common electrode;

selecting the scanning lines sequentially;

applying a voltage to said sequentially selected scanning lines, to turn on all of said switching elements connected to the said sequentially selected scanning lines;

applying said common voltage to said data lines applying said pixel voltages to said sequentially selected scanning lines, to turn off all the switching elements connected to the said sequentially selected scanning lines.

13. The method of claim 12, further comprising:

applying a plurality of voltages to said data lines, to create a plurality of electrostatic fields, to brake said pigment particles during one scanning field period after said second period, before said third period.

14. The method of claim 12, further comprising:

when a set time passes after applying to obtain a desired color gradation said plurality of voltages;

applying a voltage for resetting said pigment particles in a said first period;

applying a voltage for obtaining a desired color gradation in a said second period;

applying a voltage for holding images displayed in a said third period;

15. A method for driving an electrophoretic display, the display comprising:

a plurality of data lines;

a plurality of scanning lines, each of which intersects said data lines;

a common electrode;

a plurality of pixel electrodes, with one of said plurality of pixel electrodes being provided at one of each of said intersections of said data lines and said scanning lines, each of said pixel electrodes being provided in opposing spaced relation to said common electrode;

a plurality of dispersal systems comprising a colored fluid in which pigment particles are suspended, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and

a plurality of switching elements, with one of each of said switching elements being provided at a corresponding one of each of said intersections of said data lines and said scanning lines, with an on/off control terminal being connected to one of said scanning lines passing through one of said intersections; and

with one of said data lines passing through one of said intersections, being connected to one of said pixel electrodes provided at each of one said intersections; and

the method comprising;

controlling an image displayed by employing said scanning lines and said data lines, each of said voltages being applied within a set period of one scanning field, in which all of said scanning lines are once scanned; and

within a said set period of scanning field;

applying a voltage for resetting said pigment particles in a said first period;

applying a voltage for obtaining a desired color gradation in a said second period;

applying a voltage for holding images displayed in a said third period;

repeating application said voltages cyclically;

in said first period;

applying said common voltage to said common electrode;

selecting said scanning lines sequentially;

applying a voltage to the scanning line to turn on all the switching elements connected to the said sequentially selected scanning line;

applying to obtain desired color gradations said plurality of voltages to said data lines to create electrostatic fields, and to initialize said pigment particles;

applying a voltage to the scanning line selected, to turn off all the switching elements connected to the said sequentially selected scanning line;

in said second period;

applying said common voltage to said common electrode;

selecting the scanning line sequentially;

applying a voltage to the said sequentially selected scanning line, to turn on all the switching elements connected to the said sequentially selected scanning line;

applying a plurality of voltage to the data lines;

applying a plurality of voltages to the scanning line selected, to turn off all the switching elements which are connected to the said sequentially selected scanning line;

in said third period;

applying said common voltage to said common electrode;

selecting said scanning line sequentially;

applying a voltage to said sequentially selected scanning line, to turn on all of said switching element connected to the said sequentially selected scanning line;

applying said common voltage to dais data lines;

applying a voltage to the said sequentially selected scanning line, to turn on all of said switching elements connected to the said sequentially selected scanning line.

16. A method of claim 15, further comprising:

after said second period and before said third period;

applying a said brake voltage to said data lines, to stop rapidly movement of said pigment particles;

17. A drive circuit for an electrophoretic display, the display comprising:

a plurality of data lines;

a plurality of scanning lines, each of which intersects said data lines;

a common electrode;

a plurality of pixel electrodes, with one of said plurality of pixel electrodes being provided at one of each of said intersections of said data lines and said scanning lines, each of said pixel electrodes being provided in opposing spaced relation to said common electrode;

a plurality of dispersal systems comprising a colored fluid in which pigment particles are suspended, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and

a plurality of switching elements, with one of each of said switching elements being provided at a corresponding one of each of said intersections of said data lines and said scanning lines, with an on/off control terminal being connected to one of said scanning lines passing through one of said intersections; and

with one of said data lines passing through one of said intersections, being connected to one of said pixel electrodes provided at each of one said intersections; and

the drive circuit comprising;

an applying unit which applies said common voltage to said common electrode;

a scanning drive unit, which selects said scanning line sequentially, after applying a voltage to said scanning line selected, to turn on all of said switching elements which are connected to said sequentially selected scanning line during a certain period of time;

a data line drive unit, which applies said common voltage to data lines, after applying a plurality of pixel voltages to said data lines during a certain period of time, to migrate to a desired position corresponding to a desired color gradation, during a period in which one scanning line is selected and a voltage is applied to said said selected sequentially selected scanning lines to turn on all of said switching elements.

18. A drive circuit of claim 17, wherein said drive circuit comprises:

applying said reset voltage during a first period one field;

applying a voltage for obtaining desired color gradations during a second period;

repeating each of said voltage applications alternately;

in said first period;

applying a voltage for obtaining a desired color gradation to said data lines to create electrostatic field via said data line drive unit, to initialize said pigment particles;

in said second period;

applying a voltage gradation voltages as pixel electrodes to said data lines, which are correspondent to desired color gradations of a displayed image.

19. A drive circuit of claim 17, said data line drive unit comprising:

applying said plurality of voltages for obtaining desired color gradations to said plurality of data lines;

applying a plurality of brake voltages to said data lines, to create electrostatic field, to halt rapidly movement of said pigment particles.

20. A drive circuit of claim 19, the data line drive unit, comprising:

applying said brake voltages generated based on said pixel voltages.

21. A drive circuit of claim 17, further comprising:

applying said reset voltage during a first period of a scanning field;

applying a plurality of voltages for obtaining desired color gradations in a second period;

repeating applying said plurality of voltage for obtaining desired color gradations in the following period;

in said first period;

the data line drive unit comprising;

applying a voltage to said data lines, to create electrostatic fields, to initialize said pigment particles;

in said second period;

the data line unit comprising;

applying a voltage difference to said data lines, between a voltage corresponding to a gradation which is displayed in the previous applying voltage operation before and color gradation to be displayed next.

22. A drive circuit of claim 21, the data line drive unit comprising:

applying said plurality of voltages for obtaining desired color gradations to said data lines;

applying said plurality of brake voltages to said data lines.

23. A drive circuit for an electrophoretic display, the display comprising:

a plurality of data lines;

a plurality of scanning lines, each of which intersects said data lines;

a plurality of pixel electrodes, with one of said plurality of pixel electrodes being provided at one of each of said intersections of said data lines and said scanning lines, each of said pixel electrodes being provided in opposing spaced relation to said common electrode;

a plurality of dispersal systems comprising a colored fluid in which pigment particles are suspended, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and

a plurality of switching elements, with one of each of said switching elements being provided at a corresponding one of each of said intersections of said data lines and said scanning lines, with an on/off control terminal being connected to one of said scanning lines passing through one of said intersections; and

with one of said data lines passing through one of said intersections, being connected to one of said pixel electrodes provided at each of one said intersections; and

the drive circuit comprising;

an applying unit which applies said common voltage to said common electrode;

a scanning drive unit, which selects said scanning line sequentially, after applying a voltage to said sequentially selected scanning line, to turn on all of said switching elements which are connected to the said sequentially selected scanning line during a certain period of time;

a data line drive unit, which applies said common voltage to data lines, after applying a plurality of pixel voltages to the data lines during a certain period of time, to migrate to a position corresponding to a desired color gradation, during a period in which one of said scanning lines is selected and a voltage is applied to the said sequentially selected scanning line to turn on all of said switching elements;

applying said reset voltage during a first period of a scanning filed;

applying said plurality of voltages for obtaining desired color gradations during a different, second period;

applying said common voltage for holding images displayed during a different, third period;

repeating applying said three voltages cyclically;

in said first period;

applying a voltage to data lines, to create electrostatic field, to initialize said pigment particles;

in said second period;

applying a plurality of voltages for obtaining desired color gradations to said data lines;

in said third period;

applying said common voltage to said data lines.

24. A drive circuit of claim 23, the data line unit further comprising:

after applying said plurality of brake voltages and before applying a voltage for holding images displayed;

applying said plurality of brake voltages to said data lines, to create electrostatic fields, to halt rapidly movement of said pigment particles.

25. A drive circuit for an electrophoretic display, the display comprising:

a plurality of data lines;

a plurality of scanning lines, each of which intersects said data lines;

a plurality of pixel electrodes, with one of said plurality of pixel electrodes being provided at one of each of said intersections of said data lines and said scanning lines, each of said pixel electrodes being provided in opposing spaced relation to said common electrode;

a plurality of dispersal systems comprising a colored fluid in which pigment particles are suspended, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and

a plurality of switching elements, with one of each of said switching elements being provided at a corresponding one of each of said intersections of said data lines and said scanning lines, with an on/off control terminal being connected to one of said scanning lines passing through one of said intersections; and

with one of said data lines passing through one of said intersections, being connected to one of said pixel electrodes provided at each of one said intersections; and

the drive circuit comprising;

an applying unit which applies said common voltage to said common electrode;

a scanning drive unit, which selects one said scanning line sequentially, after applying a voltage to the scanning line selected, to turn on all of said switching elements which are connected to the said sequentially selected scanning line during a set period of time;

a data line drive unit, which applies said common voltage to data lines, after applying a plurality of pixel voltages to the data lines during a certain period of time, to migrate to a desired position corresponding to a desired color gradation, during a period in which one scanning line is selected and a voltage is applied to the said sequentially selected scanning lines to turn on all of said switching elements;

applying said reset voltage during a first period of a scanning filed;

applying said plurality of voltages for obtaining desired color gradations during a different, second period;

applying said common voltage for holding images displayed during a different, third period;

repeating applying said plurality of voltages for obtaining desired color gradations and said common voltage alternately;

in said first period;

applying a voltage to data lines, to create electrostatic field, to initialize said pigment particles;

in said second period;

applying differential voltage to the data lines, which is a difference between a voltage correspondent to a color gradation displayed in a previous applying voltage operation, and that to be displayed

in said third period;

applying said common voltage to said data lines.

26. A drive circuit of claim 25, the data line drive unit further comprising:

after said second period and before third period;

applying a plurality of brake voltages, to data lines during one scanning field, to create electrostatic field, to halt rapidly the movement of said pigment particles.

27. A drive circuit of claim 25, wherein said reset voltage is applied to the pixel electrodes regularly.

28. An electrophoretic display, comprising:

an electrophoretic panel, comprising;

a plurality of data lines;

a plurality of scanning lines, each of which intersects said data lines;

a common electrode;

a plurality of pixel electrodes, with one of said plurality of pixel electrodes being provided at one of each of said intersections of said data lines and said scanning lines, each of said pixel electrodes being provided in opposing spaced relation to said common electrode;

a plurality of dispersal systems comprising a colored fluid in which pigment particles are suspended, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and

a plurality of switching elements, with one of each of said switching elements being provided at a corresponding one of each of said intersections of said data lines and said scanning lines, with an on/off control terminal being connected to one of said scanning lines passing through one of said intersections; and

with one of said data lines passing through one of said intersections, being connected to one of said pixel electrodes provided at each of one said intersections; and

an applying unit which applies the common voltage to the common electrode;

a scanning drive unit, which selects the scanning line sequentially, after applying a voltage to the scanning line selected, to turn on all of said switching elements which are connected to the said sequentially selected scanning line during a certain period of time;

a data line drive unit, which applies said common voltage to data lines, after applying a plurality of pixel voltages to the data lines during a certain period of time, to migrate to a position corresponding to a desired color gradation, during a period in which one scanning line is selected and a voltage is applied to the said sequentially selected scanning lines to turn on all of said switching elements;

29. An electrophoretic electronic device, comprising:

an electrophoretic display panel and a display unit;

the panel comprising;

a plurality of data lines;

a plurality of scanning lines, each of which intersects said data lines;

a common electrode;

a plurality of pixel electrodes, with one of said plurality of pixel electrodes being provided at one of each of said intersections of said data lines and said scanning lines, each of said pixel electrodes being provided in opposing spaced relation to said common electrode;

a plurality of dispersal systems comprising a colored fluid in which pigment particles are suspended, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and

a plurality of switching elements, with one of each of said switching elements being provided at a corresponding one of each of said intersections of said data lines and said scanning lines, with an on/off control terminal being connected to one of said scanning lines passing through one of said intersections; and

with one of said data lines passing through one of said intersections, being connected to one of said pixel electrodes provided at each of one said intersections; and

the display unit comprising;

an applying unit which applies the common voltage to the common electrode;

a scanning drive unit, which selects the scanning line sequentially, after applying a voltage to said sequentially selected scanning line, to turn on all of said selected switching elements connected to the said sequentially selected scanning line during a certain period of time; and

a data line drive unit, which applies said common voltage to data lines, after applying a plurality of pixel voltages to the data lines during a certain period of time, to migrate to a desired position corresponding to a desired color gradation, during a period in which one scanning line is selected and a voltage is applied to the said selected scanning lines to turn on all of said switching elements.