Method and circuit for driving electrophoretic display and electronic device using same
View Patent ↗An active matrix electrophoretic display is driven. In a reset period Tr a reset voltage is applied to each pixel electrode. Next, in a writing period an applied voltage is applied to each of said pixel electrode during a time period corresponding to a gradation value designated by an image data. Next, a common voltage is applied to each of said pixel electrode, so that electric charge accumulated in each capacitor is taken away and no electric field is applied to each dispersal system, thereby a displayed image is held.
1. 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 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 including a pigment particles and a fluid, 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 one of each of said intersections; and
the method comprising:
applying a predetermined common voltage to said common electrode;
selecting said scanning lines sequentially;
applying a voltage to said selected scanning line, to turn on all switching elements connected to the said selected scanning line;
applying a constant voltage to a plurality of said data lines in order to cause said pigment particles in said pixels, said pixels being provided at said corresponding intersections of the said data lines and the said selected scanning line, to migrate to a position for desired gradations of an image displayed in the said pixels, during a time period corresponding to said desired gradations;
after application of said constant voltage to said data lines, applying a brake voltage for braking said pigment particles to the said data lines during a time period, said time period determined based on fluid resistance of said fluid and said desired gradations; and
after application of said brake voltage to said data lines, applying said common voltage to the said data lines.
2. The method of claim 1 , wherein when an image displayed is to be switched, said constant voltage is applied during a time period corresponding to a gradation difference between a gradation displayed before and after switching.
3. The method of claim 1 , further comprising the steps of:
storing brake voltage data representative of a time period during which said brake voltage is applied and image data used for displaying an image, correspondingly to a table; and
reading from said table said time data corresponding to image data of said image to be displayed.
4. The method of claim 1 , further comprising the steps of: measuring a time after finishing applying said constant voltage; and
re-applying said constant voltage to said data lines during a predetermined time period.
5. A drive circuit used 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 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 including a pigment particles and a fluid, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and
a display panel including 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 one of each of said intersections; and
the drive circuit comprising:
an applying unit for applying a predetermined common voltage to said common electrode;
a scanning line driver for selecting said scanning lines sequentially and applying a voltage to said selected scanning line, to turn on all switching elements connected to the said selected scanning line; and
a data line driver for applying a constant voltage to a plurality of said data lines in order to cause said pigment particles in said pixels, said pixels being provided at said corresponding intersections of the said data lines and the said selected scanning line, to migrate to a position for desired gradations of an image displayed in the said pixels, during a time period corresponding to said desired gradations; after application of said constant voltage to said data lines, applying a brake voltage for braking said pigment particles to the said data lines during a time period, said time period determined based on fluid resistance of said fluid and said desired gradations; and after application of said brake voltage to said data lines, applying said common voltage to the said data lines.
6. The drive circuit of claim 5 , wherein when an image displayed is to be switched said constant voltage is applied during a time period corresponding to a gradation difference between a gradation displayed before and after switching.
7. The drive circuit of claim 5 , further comprising a table to which time data representing a time period during which said brake voltage is applied and image data used for displaying an image is stored correspondingly,
wherein when displaying an image, time data corresponding to image data of said image is read from said table.
8. The drive circuit of claim 5 , further comprising a timer for counting a time so as to refreshing an image displayed in said pixels at a predetermined time.
9. An electrophoretic 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 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 including a pigment particles and a fluid, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and
a display panel including 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 one of each of said intersections;
an applying unit for applying a predetermined common voltage to said common electrode;
a scanning line driver for selecting said scanning lines sequentially and applying a voltage to said selected scanning line, to turn on all switching elements connected to the said selected scanning line; and
a data line driver for applying a constant voltage to a plurality of said data lines in order to cause said pigment particles in said pixels, said pixels being provided at said corresponding intersections of the said data lines and the said selected scanning line, to migrate to a position for desired gradations of an image displayed in the said pixels, during a time period corresponding to said desired gradations; after application of said constant voltage to said data lines, applying a brake voltage for braking said pigment particles to the said data lines during a time period, said time period determined based on fluid resistance of said fluid and said desired gradations; and after application of said brake voltage to said data lines, applying said common voltage to the said data lines.
10. The electrophoretic display of claim 9 , wherein said pigment particles reflect a certain color being displayed in said pixels and said fluid absorbs said color.
11. The electrophoretic display of claim 9 , each of said plurality of said dispersal systems includes three subsets of dispersal systems, in each of the subsets red, blue, and green particles being contained, so as to display a colored image.
12. The electrophoretic display of claim 9 , wherein said pigment particles are provided with differing properties.
13. The electrophoretic display of claim 12 , wherein said properties includes at least one of charge, size, and mass.
14. An electronic device 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 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 including a pigment particles and a fluid, with each of said dispersal systems being provided between said common electrode and one of said pixel electrodes; and
a display panel including 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 one of each of said intersections;
an applying unit for applying a predetermined common voltage to said common electrode;
a scanning line driver for selecting said scanning lines sequentially and applying a voltage to said selected scanning line, to turn on all switching elements connected to the said selected scanning line; and
a data line driver for applying a constant voltage to a plurality of said data lines in order to cause said pigment particles in said pixels, said pixels being provided at said corresponding intersections of the said data lines and the said selected scanning line, to migrate to a position of desired gradations of an image displayed in the said pixels, during a time period corresponding to said desired gradations; after application of said constant voltage to said data lines, applying a brake voltage for braking said pigment particles to the said data lines during a time period, said time period determined based on fluid resistance of said fluid and said desired gradations; and after application of said brake voltage to said data lines, applying said common voltage to the said data lines.