JP2008070546A - Method for driving electrophoresis apparatus, electrophoresis apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving method of electrophoresis device and an electrophoresis device capable of reducing a time required for switching the distribution state of electrophoresis particles in an electrophoresis element. <P>SOLUTION: The driving method of the electrophoresis element in which an electrophoretic material is disposed between a first electrode and a second electrode comprises a process of intermittently applying a DC pulse-like voltage between the first electrode and the second electrode of the electrophoresis element a plurality of times in a prescribed period. It is preferable that a period until a subsequent pulse-like voltage is applied after the preceding pulse-like voltage is applied is longer than a pulse width of the pulse-like voltage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophoresis apparatus and a driving method thereof.

  There is known an electrophoresis apparatus that utilizes the electrophoresis phenomenon of fine particles dispersed in a liquid (for example, Patent Document 1). Such an electrophoretic apparatus is used, for example, to form a thin and flexible display device (so-called electronic paper) as with a paper medium. Since this electrophoretic display displays images using reflected light, the same visual characteristics as a paper medium can be obtained. Therefore, this electrophoretic display is particularly suitable for the realization of a display device whose main purpose is to read character information and the like. Yes. In addition, the electrophoretic display has a feature (memory property) that can maintain the display contents for a certain period of time without applying voltage to the fine particles, and in addition to a liquid crystal display using a cholesteric liquid crystal having similar features. However, there is an advantage that it can be manufactured at low cost.

  The electrophoretic device moves the electrophoretic particles by applying a voltage (potential difference) between the electrodes facing each other with the electrophoretic particles interposed therebetween, thereby changing the visual recognition state. However, the conventional electrophoresis apparatus has a disadvantage that it takes a long time to switch the distribution state of the electrophoretic particles. This inconvenience becomes a factor in that it takes time to switch display images when the electrophoretic apparatus is used as a display device.

JP 2003-5227 A

  Therefore, a specific aspect of the present invention aims to provide an electrophoresis apparatus and a driving method thereof that can shorten the time required for switching the distribution state of the electrophoretic particles.

An electrophoretic element driving method according to the present invention is a method for driving an electrophoretic element in which an electrophoretic material is disposed between a first electrode and a second electrode,
Applying a DC pulsed voltage intermittently a plurality of times between the first electrode and the second electrode of the electrophoretic element within a predetermined period.
Here, the “predetermined period” is, for example, a writing period. Specifically, the writing period is, for example, from the start of signal supply to set one display state of the electrophoretic element until the display state of the electrophoretic element is set to the one display state. The period.

  According to this driving method, the pulsed voltage is repeatedly applied to the electrophoretic element a plurality of times, so that the electrophoretic element is compared with a case where a DC voltage is continuously applied within the same writing period. It is possible to shorten the time required for switching the distribution state of the electrophoretic particles. The reason may be that the electrophoretic particles continue to migrate due to inertial force by applying a pulse voltage with a short pulse width.

  Preferably, after applying the pulse voltage, a period until the next pulse voltage is applied is longer than the pulse width of the pulse voltage.

  By repeatedly applying a pulse voltage having a short pulse width in this way, the switching time of the electrophoretic particle distribution state can be further shortened.

Another method for driving an electrophoretic element according to the present invention is an electrophoretic apparatus including a panel unit configured by arranging a plurality of electrophoretic elements in which an electrophoretic material is disposed between a first electrode and a second electrode. A method of driving
The first electrode and the second electrode of each of the electrophoretic elements for each of the first to mth rows at different supply timings between the first to mth rows within a predetermined period And intermittently applying a DC pulsed voltage a plurality of times.

Another method for driving an electrophoretic element according to the present invention is an electrophoretic apparatus including a panel unit configured by arranging a plurality of electrophoretic elements in which an electrophoretic material is disposed between a first electrode and a second electrode. A method of driving
Within a predetermined period, each of the first to m-th rows is sequentially selected, and a direct-current pulse voltage is applied between the first electrode and the second electrode of each of the electrophoretic elements in the selected row. Including giving a plurality of times.

  According to these driving methods, in an electrophoretic apparatus (typically for display applications) having a large number of electrophoretic elements, the time required for switching the distribution state of electrophoretic particles of each electrophoretic element can be shortened. Is possible.

The electrophoresis apparatus according to the present invention is
An electrophoretic element in which an electrophoretic material is disposed between the first electrode and the second electrode;
Drive means for intermittently applying a DC pulsed voltage multiple times between the first electrode and the second electrode of the electrophoretic element within a predetermined period;
including.

  According to such a configuration, an electrophoretic device having a shorter time required for switching the distribution state of the electrophoretic particles of the electrophoretic element can be obtained.

Other electrophoretic devices according to the present invention are:
A panel unit configured by arranging a plurality of electrophoretic elements each having an electrophoretic material disposed between the first electrode and the second electrode;
Within the predetermined period, the first electrode and the second electrode of each of the electrophoretic elements for each of the first to m-th rows at different supply timings between the first to m-th rows. Driving means for intermittently applying a DC pulsed voltage between the plurality of times,
including.

Other electrophoretic devices according to the present invention are:
A panel unit configured by arranging a plurality of electrophoretic elements each having an electrophoretic material disposed between the first electrode and the second electrode;
Within a predetermined period, each of the first to m-th rows is sequentially selected, and a direct-current pulse voltage is applied between the first electrode and the second electrode of each of the electrophoretic elements in the selected row. Driving means that repeats giving a plurality of times;
including.

  According to these configurations, in an electrophoresis apparatus including a large number of electrophoresis elements (typically for display applications), the time required for switching the distribution state of the electrophoresis particles of each electrophoresis element can be shortened. It becomes possible.

  The above-described electrophoresis apparatus can be used as a display unit of various electronic devices, for example. Here, the “electronic device” includes all devices including a display unit that uses display by an electrophoretic material, and includes a display device, a television device, an electronic paper, a clock, a calculator, a mobile phone, a portable information terminal, and the like. Including. Further, for example, a flexible paper / film-like object, an object belonging to a real estate such as a wall surface to which these objects are attached, and an object belonging to a moving object such as a vehicle, a flying object, and a ship are included.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the overall configuration of the electrophoresis apparatus. The electrophoretic device 100 shown in FIG. 1 includes a panel unit 110, a scanning line driving circuit 130, a data line driving circuit 140, and a common electrode control circuit 150. The panel unit 110 is arranged corresponding to each of the scanning lines 101 of m rows, the data lines 102 of n columns arranged so as to intersect the scanning lines 101, and the intersections of the scanning lines 101 and 102. A transistor 103 and an electrophoretic element 104. Each electrophoretic element 104 is arranged in a matrix. A pixel portion includes the transistor 103 and the electrophoretic element 104. The transistor 103 is a p-channel transistor, for example. As the transistor 103, an organic transistor in which a semiconductor layer or the like is formed using an organic semiconductor is also preferably used.

  FIG. 2 is a circuit diagram illustrating a detailed configuration of the pixel portion. The transistor 103 as a switching element has a gate connected to the scanning line 101, a source connected to the data line 102, and a drain connected to the pixel electrode 105. A scanning signal G <b> 1 is given to the scanning line 101. The scanning signal G1 represents a scanning signal corresponding to the scanning line 101 in the first row. The scanning signals corresponding to the scanning lines 101 in the second row to m-th row are respectively expressed as scanning signals G2 to scanning signals Gn (see FIGS. 3 and 4 to be described later). A data signal DATA is supplied to the data line 102. The electrophoretic element 104 is configured by disposing an electrophoretic material (electrophoretic layer) 107 between a pixel electrode (first electrode) 105 and a common electrode (second electrode) 106. The panel unit 110 is configured by arranging a plurality of such electrophoretic elements 104. Between the pixel electrode 105 and the common electrode 106, a pixel capacitance Cepd is formed according to the electrode area of the pixel electrode 105, the distance between both electrodes, and the dielectric constant of the electrophoretic material 107. The common electrode 106 is shared by the plurality of electrophoretic elements 104 and is connected to the common electrode control circuit 150 via the wiring 201. A common electrode signal COM is supplied to the wiring 201. As the common electrode signal COM, for example, either a reference potential Vg having a relatively low potential or a power supply voltage Vs having a relatively high potential is applied.

  Here, one of the characteristic features of the electrophoresis apparatus 100 of the present embodiment is that there is no storage capacitor provided in each pixel in many conventional electrophoresis apparatuses. In general, the storage capacitor is inserted in parallel with the electrophoretic element and plays a role of holding a voltage applied to the pixel electrode 105. However, in the present embodiment, it is possible to omit the storage capacitor as illustrated by adopting a driving method described later. Note that the storage capacity is not necessarily omitted. According to the present embodiment, even if the storage capacitor is not omitted, the size can be reduced.

  The electrophoresis apparatus 100 is connected with a controller 190 as a peripheral circuit. The controller 190 includes an image signal processing circuit and a timing generator. Here, the image signal processing circuit generates image data and common electrode control data, and inputs them to the data line driving circuit 140 and the common electrode control circuit 150, respectively. The common electrode control circuit 150 supplies a common electrode signal to the common electrode 106 of the electrophoretic element 104. The timing generator generates various timing signals for controlling the scanning line driving circuit 130 and the data line driving circuit 140 when reset settings and image data are output from the image signal processing circuit.

  The transistor 103, the scanning line driving circuit 130, the data line driving circuit 140, and the common electrode control circuit 150 described above correspond to “driving means”.

  The configuration of the electrophoresis apparatus 100 of the present embodiment is as described above. Next, the driving method will be described in detail.

  FIG. 3 is a waveform diagram for explaining a driving method of the electrophoresis apparatus 100. The driving method of the present embodiment is characterized in that a DC pulse voltage is intermittently applied a plurality of times between the pixel electrode 105 and the common electrode 106 of the electrophoretic element 104 within one writing period (predetermined period). It is said. Specifically, first, the common electrode signal COM changes from the power supply potential Vs (for example, appropriately set to about +5 to 80 V), and is determined to be the reference potential Vg (for example, 0 V). This control is performed by the common electrode control circuit 150. Next, for example, when the scanning signal G1 supplied from the scanning line driving circuit 130 to the scanning line 101 in the first row becomes a low level (for example, the reference potential Vg), the transistor 103 connected to the scanning line 101 is turned on. It becomes a state. Here, since the transistor 103 of this example is a p-channel type as described above, the operation of the transistor 103 is turned on when the scanning signal G1 is at a low level (so-called low active operation). The data signal DATA applied from the data line driving circuit 140 to the pixel electrode 105 is set to either a high level potential (power supply potential Vs in this example) or a low level potential (reference potential Vg in this example). When the data signal DATA is at a high level, the data signal DATA is supplied to the pixel electrode 105 through the transistor 103, whereby the potential of the pixel electrode 105 (for example, appropriately set to about +5 to 80V) is set to the potential of the common electrode 106. It is relatively higher than (0 V in this example). If the particles contained in the electrophoretic material 107 are negatively charged, these particles are attracted to the pixel electrode 105 side. That is, the distribution state of the particles changes. As shown in the figure, when the scanning signal G1 is intermittently at a high level, a DC pulse voltage is intermittently applied between the pixel electrode 105 and the common electrode 106 a plurality of times. As a specific example, the pulse width t1 of the scanning signal G1 is, for example, about 1 millisecond, and accordingly, the pulse width of the pulse voltage is about 1 millisecond. The mutual interval t2 of the pulse voltage is about several tens of milliseconds, for example. That is, the period from when a pulse voltage is applied to the electrophoretic element 104 until the next pulse voltage is applied is significantly longer than the pulse width of the pulse voltage. In addition, the number of times that the scanning signal G1 becomes a high level within one writing period is, for example, 50 times, and accordingly, a DC pulsed voltage is intermittently applied to the electrophoretic element 104 50 times. In this way, by applying a pulse voltage having a short pulse width to the electrophoretic element 104 repeatedly over a plurality of times, compared to a case where a DC voltage is continuously applied within the same writing period, electrophoresis is performed. The time required for switching the distribution state of the electrophoretic particles of the element 104 can be shortened. The reason may be that the electrophoretic particles continue to migrate due to inertial force by applying a pulse voltage with a short pulse width.

  Although the driving method for the electrophoretic elements 104 in the first row has been described above, the electrophoretic elements 104 in other rows can be driven in the same manner. That is, within a predetermined writing period, the pixel electrode 105 and the common electrode 106 of each electrophoretic element 104 for each row from the first row to the m-th row at different supply timings from the first row to the m-th row. In the meantime, a DC pulsed voltage is intermittently applied several times. In other words, in the driving method of the present embodiment, the scanning line driving circuit 130 selectively supplies gate signals G1, G2,... Each of the m-th rows is sequentially selected and a DC pulsed voltage is applied to each of the electrophoretic elements 104 in the selected row is repeated a plurality of times. By such a driving method, it is possible to reduce the time required for switching the distribution state of the electrophoretic particles when driving the panel unit 110 including the plurality of electrophoretic elements 104 arranged in a matrix of n columns × m rows. That is, the display switching speed can be increased.

  In the driving method shown in FIG. 3, the common electrode potential COM is determined to be a low level potential in the writing period. However, as in another example shown in FIG. 4, the common electrode potential COM is determined to be a high level potential in the writing period. You may be made to do. In this case, contrary to the above description, when the data signal DATA is at a low level potential, the distribution state of the electrophoretic particles of the electrophoretic element 104 is switched.

  FIG. 5 is a perspective view illustrating a specific example of an electronic apparatus using the electrophoretic device as a display unit. FIG. 5A is a perspective view illustrating an electronic book which is an example of the electronic apparatus. The electronic book 1000 includes a book-shaped frame 1001, a cover 1002 provided to be rotatable (openable and closable) with respect to the frame 1001, an operation unit 1003, and the electrophoresis apparatus according to the present embodiment. The display unit 1004 is provided. FIG. 5B is a perspective view illustrating a wrist watch that is an example of an electronic apparatus. The wrist watch 1100 includes a display unit 1101 configured by the electrophoresis apparatus according to the present embodiment. FIG. 5C is a perspective view illustrating electronic paper which is an example of the electronic apparatus. The electronic paper 1200 includes a main body unit 1201 configured by a rewritable sheet having the same texture and flexibility as paper, and a display unit 1202 configured by the electrophoresis apparatus according to the present embodiment. Note that the range of electronic devices to which the electrophoretic device can be applied is not limited to this, and includes a wide range of devices that utilize changes in visual color tone accompanying the movement of charged particles. For example, in addition to the above-described devices, those belonging to real estate such as wall surfaces to which an electrophoretic film is bonded, and those belonging to moving bodies such as vehicles, flying objects, and ships are also applicable.

  In addition, this invention is not limited to the content of embodiment mentioned above, In the range of the summary of this invention, it can change and implement variously. For example, in the above-described embodiment, an electrophoretic device for display is illustrated, but an electrophoretic device to which the present invention can be applied is not limited to that for display. The numerical values of the applied voltage, the number of pulsed voltage applications, the pulse width, and the various conditions such as the charged state of the electrophoretic element are merely examples, and are not limited thereto.

It is a block diagram which shows the whole structure of an electrophoresis apparatus. It is a circuit diagram which shows the detailed structure of a pixel part. It is a wave form diagram for demonstrating the drive method of an electrophoresis apparatus. It is a wave form diagram for demonstrating the other example of the drive method of an electrophoresis apparatus. It is a perspective view explaining the specific example of an electronic device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Electrophoresis apparatus, 101 ... Scanning line, 102 ... Data line, 103 ... Transistor, 104 ... Electrophoretic element, 105 ... Pixel electrode, 106 ... Common electrode, 107 ... Electrophoretic material, 110 ... Panel part, 130 ... Scanning Line drive circuit 140 ... Data line drive circuit 150 ... Common electrode control circuit 190 ... Controller 201 ... Wiring

Claims (8)

A method of driving an electrophoretic element in which an electrophoretic material is disposed between a first electrode and a second electrode,
Applying a DC pulsed voltage intermittently a plurality of times between the first electrode and the second electrode of the electrophoretic element within a predetermined period;
A method for driving an electrophoretic element, comprising: In claim 1,
The predetermined period is a writing period;
A method for driving an electrophoretic element. In claim 1,
After applying the pulse voltage, a period until the next pulse voltage is applied is longer than the pulse width of the pulse voltage,
Driving method of electrophoretic element. A method of driving an electrophoresis apparatus including a panel unit configured by arranging a plurality of electrophoretic elements in which an electrophoretic material is disposed between a first electrode and a second electrode,
Within a predetermined period, the first electrode and the second electrode of each of the electrophoretic elements for each of the first to m-th rows at different supply timings between the first to m-th rows Applying a DC pulsed voltage intermittently several times during
A method for driving an electrophoretic device, comprising: A method of driving an electrophoresis apparatus including a panel unit configured by arranging a plurality of electrophoretic elements in which an electrophoretic material is disposed between a first electrode and a second electrode,
Within a predetermined period, each of the first to m-th rows is sequentially selected, and a direct-current pulse voltage is applied between the first electrode and the second electrode of each of the electrophoretic elements in the selected row. Giving more than once,
A method for driving an electrophoretic device, comprising: An electrophoretic element in which an electrophoretic material is disposed between the first electrode and the second electrode;
Drive means for intermittently applying a DC pulsed voltage between the first electrode and the second electrode of the electrophoretic element a plurality of times within a predetermined period;
An electrophoresis apparatus. A panel unit configured by arranging a plurality of electrophoretic elements each having an electrophoretic material disposed between the first electrode and the second electrode;
Within a predetermined period, the first electrode and the second electrode of each of the electrophoretic elements for each of the first to m-th rows at different supply timings between the first to m-th rows. Driving means for intermittently applying a DC pulsed voltage between the plurality of times,
An electrophoresis apparatus. A panel unit configured by arranging a plurality of electrophoretic elements each having an electrophoretic material disposed between the first electrode and the second electrode;
Within a predetermined period, each of the first to m-th rows is sequentially selected, and a direct-current pulse voltage is applied between the first electrode and the second electrode of each of the electrophoretic elements in the selected row. Driving means that repeats giving a plurality of times;
An electrophoresis apparatus.

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