JP2004252277A - Electrophoresis display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve simplification of drive circuits in an electrophoresis display device which performs display by applying voltage between an information electrode and a scanning electrode and migrating electrophoresis particles to change the display states of pixels and is used suitably to a paper-like display and the like and wherein restriction of driving time is not severe. <P>SOLUTION: In the electrophoresis display device, the scanning electrode consists of a multiple electrode constituted of first and second sub scanning electrodes to which signals are independently applied and the states of the pixels are changed by supplying selection signals to three electrodes of the first and the second sub scanning electrodes of the multiple electrode and the information electrode to apply driving selection voltage between the information electrode and the scanning electrode. Thereby, it is not needed that drive circuits are provided in proportion to the square root of the sum total number of the pixels of the electrophoresis panel and the electrophoresis panel can be driven by a small number of drive circuits. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophoretic display device that performs display by changing the state of a pixel by moving electrophoretic particles included in the pixel between a scanning electrode and an information electrode.
[0002]
[Prior art]
Conventionally, as a display device other than an electrophoretic display device, in STN and FLCD liquid crystal display devices, according to Japanese Patent Application Laid-Open No. 2000-56291 (Patent Document 1), a plurality of matrix electrodes are driven by wiring scanning electrodes through resistors. It is possible to perform high-resolution display.
[0003]
On the other hand, in the electrophoretic display device, as the number of drive circuits increases as the resolution increases, the mounting width of the drive circuit IC becomes narrower, and mounting becomes more difficult. In addition, as the number of drive ICs increases, the cost of the drive ICs occupies a large proportion of the entire electrophoretic display device. Therefore, a low-temperature polysilicon method can be considered as a method that does not use an external drive IC. The low-temperature polysilicon method is a manufacturing method in which polycrystalline silicon can be produced at a low temperature such as the heat-resistant temperature of a glass substrate or lower, so that a drive circuit can be monolithically integrated together with a transistor of a pixel of a display device.
[0004]
[Patent Document 1]
JP-A-2000-56291
[0005]
[Problems to be solved by the invention]
However, since the electrophoretic display device is required to have flexibility, low cost, and a large screen, it is difficult to adopt the low-temperature polysilicon method. For this reason, it is required to reduce the cost of the drive IC by a method other than monolithically integrating the drive circuit as in the low-temperature polysilicon method.
[0006]
That is, if the number of output channels of the drive circuit can be reduced without reducing the number of pixels of the display device, the cost of the drive circuit can be dramatically reduced.
[0007]
In general, a paper-like display using electrophoretic display is required to be able to be written with low power consumption. However, since the main purpose is to display a still image without displaying a moving image, it is necessary to display one frame. There is a feature that the driving time can be somewhat increased even if it is slightly longer.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to reduce the number of output channels of a drive circuit in an electrophoretic display device in which the drive time is loosely limited, thereby reducing the cost of the drive circuit. And
[0009]
[Means for Solving the Problems]
The means for solving the above problems are as follows.
[0010]
[Solution 1]
Each of the pixels includes a plurality of pixels including electrophoretic particles movably held by a holding member, and selectively applying a drive selection voltage through a scanning electrode and an information electrode electrically connected to the pixels. In an electrophoretic display device for determining a state,
A scan drive circuit for supplying a scan signal to the scan electrode,
An information drive circuit for supplying an information signal to the information electrode;
With
At least one of the scanning electrode and the information electrode is a composite electrode composed of first and second sub-electrodes to which signals are independently applied,
The scan drive circuit or the information drive circuit has a first sub-electrode drive circuit and a second sub-electrode drive circuit connected to the first and second sub-electrodes, respectively.
The pixel is driven by a selection signal being supplied to three electrodes, the first and second sub-electrodes of the composite electrode and the information electrode or the scanning electrode, which are electrically connected thereto. An electrophoretic display device in which a selection voltage is applied and the state of the pixel changes.
[0011]
[Solution 2]
Each of the pixels includes a plurality of pixels including electrophoretic particles movably held by a holding member, and selectively applying a drive selection voltage through a scanning electrode and an information electrode electrically connected to the pixels. In an electrophoretic display device for determining a state,
A scan drive circuit for supplying a scan signal to the scan electrode,
An information drive circuit for supplying an information signal to the information electrode;
With
The scanning electrode is a composite electrode composed of first and second sub-scanning electrodes to which signals are independently applied,
The scan drive circuit has a first scan drive circuit and a second scan drive circuit connected to the first and second sub-scan electrodes, respectively.
The drive selection voltage is applied to the pixel by supplying a selection signal to three electrodes, the first and second sub-scanning electrodes and the information electrode, of the composite electrode electrically connected thereto. An electrophoretic display device, wherein a state of the pixel is changed by being applied.
[0012]
[Solution 3]
Each of the pixels includes a plurality of pixels including electrophoretic particles movably held by a holding member, and selectively applying a drive selection voltage through a scanning electrode and an information electrode electrically connected to the pixels. In an electrophoretic display device for determining a state,
A scan drive circuit for supplying a scan signal to the scan electrode,
An information drive circuit for supplying an information signal to the information electrode;
With
The information electrode is a composite electrode composed of first and second sub-information electrodes to which signals are independently applied,
The scan drive circuit has a first scan drive circuit and a second scan drive circuit connected to the scan electrode and the second sub information electrode, respectively.
The drive selection voltage is applied to the pixel by supplying a selection signal to three electrodes of the composite electrode electrically connected thereto, that is, the first and second sub-information electrodes and the scanning electrode. An electrophoretic display device, wherein a state of the pixel is changed by being applied.
[0013]
[Solution 4]
In the above-mentioned composite electrode, a first sub-electrode and a second sub-electrode each having a comb shape are formed on the same plane in a state where teeth of a comb are engaged with each other. The electrophoretic display device according to any one of means 1 to 3.
[0014]
[Solution 5]
The composite electrode has a multilayer shape, and an insulating layer is formed between a sub-electrode far from the electrophoretic particles and a sub-electrode near the electrophoretic particles. 4. The electrophoretic display device according to any one of items 1 to 3.
[0015]
[Solution 6]
A large number of pixels including electrophoretic particles movably held by a holding body are arranged in a two-dimensional matrix, and an electrophoretic display device that determines a state of each pixel by selectively applying a drive selection voltage to the pixels. At
An electrophoretic display device, wherein three electrodes are electrically connected to the pixel, and a driving circuit that drives the three electrodes in a three-dimensional matrix is provided.
[0016]
Further, the three-dimensional matrix driving includes four-dimensional matrix driving.
[0017]
The drive selection voltage is a voltage that can be applied to a pixel and change the display state of the pixel only when three electrodes driven in a three-dimensional matrix are simultaneously selected (1 or 0 in the truth table). The drive selection voltage may be determined such that a voltage pulse train is applied to the selected pixel after the erasing voltage is applied to the pixel at least for each pixel, at least for each line, or for each frame.
[0018]
Here, the holding body may be a capsule, a pair of substrates whose periphery is sealed, or a combination thereof.
[0019]
Further, the two electrodes constituting the composite electrode each preferably have a plurality of portions discretely provided for one pixel. Specifically, as described later, a plurality of comb-shaped portions may be arranged in one pixel as a comb-shaped electrode structure. Further, it is preferable that at least one capsule is arranged in one pixel having a plurality of comb-tooth portions, and a large number of electrophoretic particles are contained in the capsule.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these specific embodiments.
[0021]
FIG. 1 is a schematic block diagram of an electrophoretic display device according to one embodiment of the present invention.
[0022]
In the figure, 11 is a data input unit, 12 is a data modulator, 13 is an information electrode driver (information drive circuit), and a display signal and a clock signal from the data input unit 11 are sent to the data modulator 12. After that, the data signal is converted into an information signal and an auxiliary signal in the data modulator 12, and then supplied to the information electrode formed on a substrate (not shown) holding the electrophoretic particles of the electrophoretic panel 19 through the information electrode driver 13. Is done.
[0023]
Further, in the figure, 14 is a clock generator, 15 is a scan electrode selector for selecting a scan electrode (not shown), and 16 and 17 are A and B scan electrode drivers (the first scan drive circuit and the second scan drive circuit, respectively). After the clock signal generated by the clock generator 14 is sent to the scan electrode selector 15, the scan electrodes selected by the scan electrode selector 15 are supplied to the A and B scan electrode drivers 16 and 17 (first drive). Circuit).
[0024]
In FIG. 1, reference numeral 18 denotes a matrix wiring section which connects the A and B scanning electrode drivers 16 and 17 to one scanning electrode by matrix wiring.
[0025]
The outputs from the A and B scan electrode drivers 16 and 17 are supplied by the matrix wiring section 18 as one output pair to the scan electrodes of the electrophoretic panel 10 which are composed of composite electrodes (not shown).
[0026]
FIG. 2 is a diagram for explaining a connection state between the composite electrode and the matrix wiring section 18. The input terminals of four sub-scanning electrodes COMA-1 to COMA-4 connected to the A-scanning electrode driver 16; It has input terminals for eight sub-scanning electrodes COMB-1 to COMB-8 connected to the B-scanning electrode driver 17. The number of input terminals, that is, the number of drive lines is four or eight for the sake of simplicity of description, but in practice, the number is usually several tens to several hundreds.
[0027]
The matrix wiring section 18 includes a composite electrode group including a comb-shaped electrode group connected to the A-scanning electrode driver 16 and a comb-shaped electrode connected to the B-scanning electrode driver 7, for example, in the drive line COMA-1 (121). The sub-scanning electrodes A-1 and B-1, A-1 and B-2,..., A-1 and B-8, which are arranged in non-contact and close contact with each other in parallel with each other, are connected to a drive line COMA. -2, the sub-scanning electrodes A-2 and B-1, A-2 and B-2,..., A-2 and B-8, and so on. These are wiring portions connected in a matrix. Then, by combining in this way, eight sub-scanning electrodes 1 to 8 are formed corresponding to the drive line COMA-1.
[0028]
Then, the same close arrangement is performed also on the sub-scanning electrodes of the drive lines COMA2 to COMA4, whereby the scanning electrode group 23 extending around the electrophoretic panel 19 has 4 × 8 = 32 lines. A scanning electrode composed of a composite electrode is formed.
[0029]
More specifically, a total of 32 first sub-scanning electrodes are provided, one for each of the four input terminals COMA-1 to COMA-4. A total of 32 second sub-scanning electrodes arranged in parallel with each other are further provided, which are commonly connected to any of the common input terminals COMB-1 to COMB-8 every four lines. Have been. In this way, the matrix wiring section 18 realizes a 4 × 8 matrix of four input terminals COMA-1 to COMA-4 and eight input terminals COMB-1 to COMB-8. Therefore, a scan electrode composed of 32 composite electrodes can be driven in a time-division manner by a 4 × 8 matrix.
[0030]
Note that, as described above, the first sub-scanning electrodes are grouped into a plurality of first sub-scanning electrode groups each including a fixed number of first sub-scanning electrodes. The first sub-scanning electrode belonging to the first sub-scanning electrode is connected to one input terminal of the first scanning drive circuit, and the second sub-scanning electrode is paired with one first sub-scanning electrode in each first sub-scanning electrode group. Are grouped into a plurality of second sub-scanning electrode groups consisting of second sub-scanning electrodes constituting a composite electrode, and the second sub-scanning electrodes belonging to one second sub-scanning electrode group are By connecting to one input terminal of the second scanning drive circuit, matrix wiring can be performed with a simple configuration, which can be said to be a preferable mode. However, the present invention is not limited to this connection mode.
[0031]
FIG. 6 is a plan view showing a detailed shape of one embodiment of the composite electrode used in the present invention.
[0032]
The first sub-scanning electrode 21 and the second sub-scanning electrode 22 are formed on the same plane, 21 has a comb-like shape facing downward, 22 has a comb-like shape facing upward, and each of the comb teeth has a non-comb shape. The composite electrode is configured so as to be engaged by contact. COMA1 to COMA4 correspond to COMB1 to COMB8, respectively, and are composed of a total of 32 composite electrodes.
[0033]
FIG. 3 is a diagram illustrating signal waveforms applied to each scanning electrode from two scanning driving circuits (A and B scanning electrode drivers 16 and 17) in the electrophoretic display device of the present invention. In the figure, reference numeral 311 denotes a waveform of a selection signal, which is a predetermined signal (hereinafter, abbreviated as a selection waveform), and 312, a waveform of a non-selection signal (hereinafter, abbreviated as a non-selection waveform).
[0034]
Here, the selected waveform 311 is composed of an erase pulse 316 and a write pulse 317, and the non-selected waveform 312 is a pulse that is ／ of the selected waveform 311. Then, the selection waveform 311 is applied to, for example, only the drive line A1 among the drive lines A1 to A4 of the A scan electrode driver 6 in FIG. 2, and the non-selection waveform 312 is applied to the other drive lines. .
[0035]
Similarly, of the drive lines B1 to B8 of the B scan electrode driver 7, the selection waveform 311 is applied only to the drive line B1, for example, and the non-selection waveform 312 is applied to the other drive lines.
[0036]
Here, since the comb electrodes connected to the drive lines A1 to A4 and the drive lines B1 to B8 are arranged in a matrix, both the selection waveforms 311 are applied to the composite electrode only to the scan electrodes A1 to B1. . When both the selection waveforms 311 are applied as described above, since the two selection waveforms 311 are the same, the same pulse as the selection waveform 311, that is, the selection pulse 313 is applied to the scan electrodes A <b> 1-B <b> 1.
[0037]
On the other hand, the non-selection waveform 312 and the non-selection waveform 312, or the selection waveform 311 and the non-selection waveform 312 are applied to the scan electrodes other than the scan electrodes A1-B1 through the composite electrode. When the sum of the electric fields on the composite electrode is shown, the former has a waveform of 314, and the latter has a waveform of 315.
[0038]
As described above, the scan signal waveform substantially applied to the scan electrode constituted by the composite electrode includes:
1. A selection pulse 313 formed by applying a selection waveform 311 to the A and B scan electrode drivers 16 and 17
2. A first non-selection pulse 314 formed by applying the selection waveform 311 to the A scan electrode driver 16 and the non-selection waveform 312 to the B scan electrode driver 17, respectively.
3. A first non-selection pulse 314 formed by applying a selection waveform 311 to the B scan electrode driver 17 and a non-selection waveform 312 to the A scan electrode driver 16, respectively.
4. Second non-selection pulse 315 formed by applying non-selection waveform 312 to A and B scan electrode drivers 16 and 17
Thus, there are four signal waveforms.
[0039]
FIGS. 4A and 4B are diagrams illustrating the voltage applied to the information electrode and the resulting electric field strength between the scanning electrode and the information electrode in the electrophoretic display device of the present invention. (A) is a diagram when an ON voltage is applied to the information electrode. (B) is a diagram when an OFF voltage is applied to the information electrode.
[0040]
321 is an information signal waveform applied to the information electrode, which is white.
[0041]
When the selection waveform 311 (see FIG. 3) is applied to each of the drive lines A1 to A4 and B1 to B8 of the A and B scan electrode drivers 16 and 17, the selection as shown in FIG. A scanning signal waveform including the pulse 313 is applied to only one scanning electrode selected by matrix driving.
[0042]
When the selection pulse 313 is applied to one scan electrode, the first non-selection pulse 314 having only one of the selection waveforms is applied to 11 scan electrodes of the other 31 scan electrodes, A second non-selection pulse 315 having both non-selection waveforms is applied to the 20 scanning electrodes.
[0043]
Then, when the composite waveform 322 of the selection waveform 313 and the information waveform 321 is applied, a black erasing voltage is applied at a portion 325 of the composite waveform 322, and the pixel becomes black. A white writing voltage is applied to make the pixel white.
[0044]
The electric field intensity waveform between the information waveform 321 and the first non-selective scanning waveform 314 is 323, and the electric field intensity waveform between the information waveform 321 and the second non-selective scanning waveform 315 is 324.
[0045]
Then, with respect to the threshold electric field intensity at which the state of the pixel transitions from white to black or from black to white, the electric field intensity waveform 322 exceeds the threshold value and 324 indicates a value that does not exceed the threshold value. Rewriting occurs in the waveform 322 and rewriting occurs in the waveforms 323 and 324 by setting physical design conditions such as the distance between the electrodes and the material of the electrophoretic particles, or setting the voltage value of a signal to be applied. Can not be.
[0046]
Next, FIG. 4B is a diagram illustrating a voltage waveform and an electric field generated by a voltage difference when an OFF voltage is applied to the information electrode.
[0047]
Reference numeral 331 denotes an information waveform of all pixels black, and reference numeral 332 denotes a composite waveform of the information waveform 331 of all pixels black and the scanning signal waveform 313. When such a composite waveform 332 is applied, a black erasing voltage is applied to a portion indicated by 335 of the composite waveform 332, and the pixel becomes black. At 336, since the absolute value of the electric field strength is lower than the threshold value, there is no change from the previous state.
[0048]
The electric field intensity waveform between the information waveform 331 and the first non-selection scanning waveform 314 becomes 333, and the electric field intensity waveform between the information waveform 331 and the second non-selection scanning waveform 315 becomes 334. These also do not affect the operation by setting the threshold value and the voltage in the same manner as in FIG.
[0049]
As described above, only the electric field intensity waveform portions 325, 326, and 335 shown in FIGS. 4A and 4B are related to the operation. This means that only the selection pulse 313 is involved in the operation. The selection pulse 313 is generated when the selection waveform 311 is simultaneously applied to one of the drive lines A1 to A4 and B1 to B8 of the A and B scan electrode drivers 16 and 17 at the same time. . In this way, it can be understood that all the pixels can be freely controlled to be white or black by the three-dimensional matrix driving including the drive lines A1 to A4 and B1 to B8 of the A and B scan electrode drivers 16 and 17 and the information lines.
[0050]
Next, FIG. 5 is a diagram illustrating the order of waveforms applied from the A and B scan electrode drivers 16 and 17 to each drive line.
[0051]
In the figure, reference numeral 341 denotes a signal of the first pin of the COMA line, 342 denotes a signal of the second pin of the COMA line, 343 denotes a signal of the first pin of the COMB line, and 344 denotes a signal of the second pin of the COMB line. The signal 345 is the first line selection timing from the frame synchronization, and 346 is the second line selection timing from the frame synchronization.
[0052]
Here, the A1 waveform 341 is a waveform in which the selected waveform 311 is repeated eight times, then the non-selected waveform 312 is repeated 24 times, and one set includes 32 waveforms. In FIG. 5, the waveform after the twelfth waveform is omitted.
[0053]
The A2 waveform 342 is a waveform in which the non-selected waveform 312 is repeated eight times, then the selected waveform 311 is repeated eight times, and then the non-selected waveform 312 is repeated sixteen times. As described above, the A line issues the selection signal only eight times, which is the number of B lines.
[0054]
The B1 waveform 343 is a waveform in which the selected waveform 311 is output once, and then the non-selected waveform 312 is repeated seven times, and one set of eight waveforms.
[0055]
The B2 waveform 344 is a waveform in which a non-selected waveform 312 is output once, a selected waveform 311 is output once, and then the non-selected waveform 312 is repeated six times, and one set of eight waveforms is provided. In this way, the B line outputs a selection signal only once every eight times, which is the number of B lines.
[0056]
At the first timing 345, only COMA1 and COMB1 have the selected waveform, and only the first composite electrode connected to them has the selected potential.
[0057]
At the second timing 346, only COMA1 and COMB2 have the selected waveform, and only the second composite electrode connected to them has the selected potential.
[0058]
In this way, the 1st to 32nd lines become the selection potential in accordance with the timings 1 to 32.
[0059]
For example, if the number of drive lines of the A scan electrode driver 16 is 50, the number of drive lines of the B scan electrode driver 17 is 40, and the number of drive lines of the information electrode driver is 2000, the electrophoretic panel of 4 million pixels is used. 19 can be driven.
[0060]
Then, two scan electrode drivers 16 and 17 are connected to one scan electrode composed of two sub-scan electrodes arranged in close contact with each other in this manner, and a selection waveform 311 is output from both scan electrode drivers 16 and 17. By applying the selection pulse 313 to the scanning electrode only when the scanning line is applied, it is not necessary to provide a drive line in proportion to a half power with respect to the resolution of the electrophoretic panel 19, and the number of drive lines is small. The electrophoretic panel 19 can be driven by the scanning electrode drivers 16 and 17 having the following.
[0061]
In the above description, the scan electrode drivers 16 and 17 are provided separately, but may be configured in one IC package. Further, by performing a two-dimensional or higher-dimensional matrix connection, it is possible to further reduce the number of drive lines of the scan electrode driver. For example, if the number of scan electrodes is 2000, it is possible to use three scan electrode drivers and configure the number of drive lines of each scan electrode driver to be 20 + 10 + 10, that is, 40 lines.
[0062]
In the above description, the case where the same selection waveform of the same voltage is applied to the drive lines of the scan electrode drivers 16 and 17 has been described. However, selection waveforms of different voltages may be applied.
[0063]
As described above, the electrophoretic display device of the present invention in which a scanning electrode is formed as a composite electrode by two sub-scanning electrodes has been described using a comb electrode pair as shown in FIG. 6 as an example of a particularly preferable electrode arrangement. The preferred electrode arrangement in the embodiment of the invention is not limited to this, but may be any electrode configuration that can apply a voltage between two sub-scanning electrodes.
[0064]
FIG. 13 shows a schematic plan view and a cross-sectional view of the pair of comb electrodes of FIG. Such an electrode may be formed, for example, by forming the electrode 21 and the electrode 22 on the substrate (holding member) 201 by a photolithography method.
[0065]
In FIG. 14, the planar arrangement of the electrodes is the same as that of FIG. 13, but the insulating layer 202 is thinly arranged on the outermost surface of the substrate so as to cover the electrodes. This is preferable in order to prevent the occurrence of an electrochemical reaction or the like between the electrode 21 or the electrode 22 and the insulating liquid, thereby preventing the insulating liquid from deteriorating.
[0066]
In FIG. 15, the planar arrangement of the electrodes is the same as that of FIG. 13, but the electrodes 21 and the electrodes 22 are formed in multiple layers. For such an electrode, for example, after forming one electrode 22 on a substrate 201 by a photolithography method, the insulating layer 202 may be formed thin, and the other electrode 22 may be formed thereon by a photolithography method. By arranging the insulating layer between the electrodes, it is difficult for a leak to occur even when the distance between the electrodes is to be reduced.
[0067]
Further, an insulating layer (not shown) may be formed thin on this.
[0068]
FIG. 16 shows a case where one of the electrodes 21 is formed as a plane electrode and the plane arrangement of the electrodes is slightly different from that of FIG. 13, and corresponds to a scanning electrode configuration as shown in FIG. 7 described later. Such an electrode may be formed, for example, by forming one electrode 21 as a surface electrode on a substrate 201 by a photolithography method, forming an insulating layer 202 thinly, and further forming one electrode 22 thereon by a photolithography method. Since there is an insulating layer between the electrodes, leakage between the electrodes is unlikely to occur, and the fineness of the one electrode 21 is not so required, so that manufacture is easy. Further, an insulating layer (not shown) may be formed thin on this.
[0069]
The above-described various electrodes 21 and 22 can be made of a transparent conductive material such as ITO (indium tin oxide), or a metal or alloy such as Al, Pt, Au, or Ti. These electrodes 21 and 22 are preferably formed by an evaporation method, a sputtering method, a photolithography method, a plating method, or the like.
[0070]
For example, if a fine particle having a diameter of about 1 to 5 μm is used for the migrating particles, and the two sub-scanning electrodes 21 and 22 are formed with a thickness of about 0.1 to 0.5 μm, the two comb-shaped electrodes are The entire width of the composite electrode formed by meshing is 2 to 10 μm, the length of the comb portion is about 70 to 95% of the entire width of the composite electrode, and the width of the comb of the comb-shaped electrode 21 is 0.5 to 95%. A thickness of about 3 μm is one of the preferable embodiments from the viewpoint of controllability of the formed electric field and high definition of the electrophoretic display device.
[0071]
Also, if a relatively large electrophoretic particle having a diameter of about 5 to 30 μm is used, the width of the entire composite electrode formed by engaging two comb-shaped electrodes is 10 to 60 μm, and the length of the comb portion is the same as that of the composite electrode. It is preferable to set the width of the comb of the comb-shaped electrode 21 to about 2 to 15 μm from the viewpoint of controllability of the formed electric field, high definition of the electrophoretic display device, and the like. It is mentioned as another example of the form.
[0072]
The substrate 201 used as the holder and the opposite substrate (not shown) are made of a hard material such as glass or quartz, polyethylene terephthalate (PET), polyether sulfone (PES), polyimide (PI), polycarbonate (PC), or the like. A flexible material can be used.
[0073]
Further, as a material of the insulating layer 202, a material that is thin and hard to form a pinhole is preferable, and for example, polyimide, PET, or the like having high transparency can be used.
[0074]
When actually manufacturing a display panel using the above-described electrode configuration, it is preferable that the migrating particles and the insulating liquid are separated for each pixel so that interference due to particle movement between adjacent pixels does not occur, For that purpose, it is preferable to have a microcapsule or partition structure.
[0075]
Insulating liquid as a dispersion medium containing migrating particles includes a known azo dye in a colorless transparent liquid such as an aliphatic hydrocarbon, a halogenated hydrocarbon, an alcohol solvent, silicone oil, toluene, xylene, and high-purity petroleum. , Anthraquinone dye, triphenylmethane dye, metal dye and the like are preferably used alone or in combination, and colored ones can be used appropriately.
[0076]
As the migrating particles, for example, white particles can be used by dispersing them in the insulating liquid colored as described above. For example, in addition to inorganic pigments such as titanium oxide, zinc oxide and zinc sulfide, fine powders such as glass or resin, and composites thereof are preferably used. In addition, if necessary, the surface of the particles can be treated with various surfactants, dispersants, organic and inorganic compounds, metal compounds, and the like to perform desired charging and dispersion stabilization.
[0077]
If the diameter of the migrating particles is as small as about 1 μm to 5 μm, high-definition display is facilitated. However, in the present invention, the distance between the first sub-scanning electrode and the second sub-scanning electrode is significantly smaller. Fine particles are not preferred. The distance between the pair of sub-scanning electrodes is preferably about 10 μm or less if the particle diameter is about 5 μm, for example.
[0078]
When relatively large electrophoretic particles of about 5 to 30 μm are used, the distance between the pair of sub-scanning electrodes is desirably about 50 μm or less.
[0079]
FIG. 17 and FIG. 18 are schematic diagrams for explaining the display state of the present invention.
[0080]
FIG. 17 is a schematic diagram showing a black display, and FIG. 18 is a schematic diagram showing a white display.
[0081]
17 and 18, 21, 22, 201, and 202 are the same as those in FIG. 13, 271 is an upper transparent substrate, 272 is an information transparent electrode, 273 is a microcapsule filled with an insulating liquid, and 274 is white electrophoresis. Particles.
[0082]
At the time of black erasure described above, white electrophoretic particles accumulate on the lower side as shown in a schematic diagram 17 and black display is performed.
[0083]
At the time of white writing, as shown in FIG. 18, white electrophoretic particles accumulate on the upper side, and when viewed from the upper side, they become white and display white.
[0084]
As described above, it is preferable that one or two or more capsules are arranged in one pixel having the plurality of comb-tooth portions 21 and 22, and a large number of electrophoretic particles are contained in the capsules.
[0085]
Here, the description has been given of the combination of the black liquid and the white particles, but the present invention can be similarly implemented with the combination of the white liquid and the black particles.
[0086]
In addition, if RGB color particles are used instead of the white particles, color display can be similarly performed. Alternatively, color display can be similarly performed by using a liquid of YMC color instead of the black liquid.
[0087]
Note that the transition of the state of the pixel in the present invention means that the migration of the migrating particles between the electrodes as described above causes a white display to be changed to a black display or a black display to be changed to a white display in the case of a monochrome display device. In the case of a color display device, the display color state changes.
[0088]
Next, some specific embodiments of the present invention will be described.
[0089]
(Embodiment 1)
Embodiment 1 of the present invention will be described.
[0090]
FIG. 7 showing this embodiment is a diagram showing a detailed shape of an embodiment of a composite electrode constituting the present invention, and is a diagram in a case where two sub-scanning electrodes are vertically overlapped. (A) is a plan view. (B) is a side view.
[0091]
In the present embodiment, the electrodes connected to each drive line of the A scan electrode driver 16 are comb-shaped, and the electrodes connected to each drive line of the B scan electrode driver 17 are square planar electrodes. Thus, they are formed in two separate layers to form a multilayer structure.
[0092]
Even in the case where the comb electrode pattern portions having such a relationship are provided, the signal waveforms output from the A and B scanning electrode drivers 16 and 17 to the matrix wiring portion are as shown in FIG.
[0093]
For this reason, the insulating layer 51 between 21 and 22 needs to be made sufficiently thin.
[0094]
Further, it is necessary to make the width of the comb of the upper comb-shaped electrode 21 sufficiently small.
[0095]
For example, when the two sub-scanning electrodes 21 and 22 are formed with a thickness of about 0.1 to 0.5 μm, the thickness of the insulating layer 51 is about 0.2 to 3 μm, and the width of the square electrode (this is approximately The width of the comb portion is about 70 to 100% of the width of the rectangular electrode (the width of the entire composite electrode), and the width of the comb of the comb-shaped electrode 21 is 0 to 1000 μm. The thickness is preferably about 0.5 to 3 μm. Here, the insulator used for the insulating layer is desirably one having a high withstand voltage and a low dielectric constant even if it is thin because a favorable electric field distribution can be obtained.
[0096]
In such a two-layer structure, since the lower sub-scanning electrode is far from the electrophoretic particles, a voltage higher than that of the upper sub-scanning electrode is applied.
[0097]
If the structure of the upper layer in FIG. 7 is the comb-shaped electrode pair in FIG. 6, it can be easily inferred that a composite electrode having a three-electrode structure can be formed. Furthermore, if the lower layer is also a comb-shaped electrode pair, it has a four-electrode structure.
[0098]
Thus, the number of electrodes in the composite electrode structure can be increased to an arbitrary number to some extent.
[0099]
Further, by insulating the upper and lower portions, not only a comb shape but also an arbitrary shape such as a shape in which many points are mixed can be obtained.
[0100]
(Embodiment 2)
Next, a second embodiment of the present invention will be described.
[0101]
FIG. 8 showing the present embodiment is a diagram showing a detailed shape of one embodiment of a composite electrode constituting the present invention, and is a diagram showing another case where two sub-scanning electrodes are vertically overlapped. (A) is a plan view. (B) is a side view.
[0102]
Also in the present embodiment, as in the first embodiment, a comb-shaped electrode connected to each drive line of the A scan electrode driver 16 and a square electrode connected to each drive line of the B scan electrode driver 17 are: It has a two-layer structure.
[0103]
However, the present embodiment is characterized in that the shape of the comb teeth of the electrode 21 extends in the long direction of the electrode.
[0104]
In this configuration, the visible area at the center of the panel can be constituted only by the comb teeth. As a result, as shown in FIG. 7, there is no deviation of the electric field between the shaft portion and the tooth portion of the comb, and a uniform electric field can be formed.
[0105]
When the comb-shaped electrode is formed in a shape in which the comb teeth extend in the longitudinal direction as in the present embodiment, for example, when the two sub-scanning electrodes 21 and 22 are formed with a thickness of about 0.1 to 0.5 μm In addition, the thickness of the insulating layer 51 is about 0.2 to 3 μm, the width of the square electrode (which approximately corresponds to the entire width of the composite electrode) is about 30 to 1000 μm, and the width of the comb of the comb-shaped electrode 21 is 0.5 to The thickness is preferably about 3 μm.
[0106]
As described above, the essential point of the composite electrode in the present invention is to mix two or more potentials, and the shape and three-dimensional structure of the composite electrode itself are arbitrary as long as the potentials are mixed.
[0107]
Here, in order to further contribute to the understanding of the contents of the present invention, a difference between the conventional technique and the technique of the present invention is shown using a truth table summarizing the state of operation, and the scanning electrode having the composite electrode structure of the present invention is shown. Make clear what works.
[0108]
FIG. 12 shows a state of operation in a conventional example in a truth table.
[0109]
In FIG. 12, the scanning line is represented by COM, the information line is represented by SEG, COM = 0 is not selected, COM = 1 is selected, SEG = 0 is erasing only, and SEG = 1 is writing after erasing. Shall be supplied. Y indicates that the total potential of COM and SEG exceeds the threshold, and N indicates that the total potential does not exceed the threshold.
[0110]
When COM is the non-selection potential, the threshold value is not exceeded regardless of the value of SEG. When COM is at the selected potential, when the SEG is erased, the threshold is exceeded only for erase. When the SEG is write after erase, the threshold is exceeded for both the erased portion and the written portion.
[0111]
FIG. 9 summarizes the operation status in the first and second embodiments in a truth table.
[0112]
In FIG. 9, the scanning line is represented by COMA and COMB, and the information line is represented by SEG. In COMA and COMB, 0 represents non-selection, 1 represents selection, SEG = 0 represents erasing only, and SEG = 1 represents writing after erasing. , And a potential corresponding to each of them is supplied. Y indicates that the total potential of COM and SEG exceeds the threshold, and N indicates that the total potential does not exceed the threshold.
[0113]
When either COMA or COMB is the non-selection potential, the threshold value is not exceeded regardless of the value of SEG. Only when both COMA and COMB are at the selected potential, when the SEG is erased, only the erase threshold is exceeded, and when the SEG is write after erase, the threshold is exceeded for both erased and written parts.
[0114]
(Embodiment 3)
Next, a case where a composite electrode is formed between a scanning electrode and an information electrode will be described as a third embodiment.
[0115]
FIG. 10 is a schematic block diagram of the electrophoretic display device according to the third embodiment.
[0116]
In the figure, 11 to 13 are the same as in FIG. 1, 81 is a scan electrode selector, 82 is a scan electrode driver, 83 is an information side scan electrode driver C for driving an information side scan line, and is generated by the clock generator 14. After the clock signal is sent to the scan electrode selector 81, the scan electrode driver 82 and the information side scan electrode driver C83 selected by the scan electrode selector 81 are driven, and the scan electrodes are driven by the scan electrode driver 82. . The information side scan electrode driver C83 will be described below.
[0117]
In the figure, reference numeral 84 denotes a matrix wiring section (matrix connection section) for connecting an information electrode driver and an information-side scanning electrode driver C83 in a matrix to an information electrode composed of one composite electrode by matrix wiring.
[0118]
The outputs from the information electrode driver 13 and the information-side scanning electrode driver C83 are supplied as one output from the matrix wiring section 84 to the information electrodes composed of the composite electrodes (not shown) of the electrophoretic panel 85.
[0119]
The electrode of the present embodiment may be formed by forming the information electrode and one sub-scanning electrode in the same structure as the composite electrode (scanning electrode composed of two sub-scanning electrodes) described in the first and second embodiments. The setting of the voltage applied to the electrodes and the scanning electrodes can be easily performed according to the concept of the present invention described in the above embodiment.
[0120]
FIG. 11 summarizes the operation status in the truth table in the third embodiment.
[0121]
In FIG. 11, the scanning line is represented by COM, the information line is represented by SEG, and the information side scanning line is represented by COMC. In COM and COMC, 0 represents non-selection, 1 represents selection, SEG = 0 represents erasing only, and SEG = 1 supplies a potential corresponding to each of writing after erasing. Y indicates that the total potential of COM and SEG exceeds the threshold, and N indicates that the total potential does not exceed the threshold.
[0122]
As shown in FIG. 11, when either COM or COMC is the non-selection potential, the threshold value is not exceeded regardless of the value of SEG. Only when both COM and COMC are at the selected potential, the threshold exceeds only the erasure when the SEG is erased, and exceeds the threshold in both the erased portion and the written portion when the SEG is write after erase.
[0123]
(Embodiment 3)
In the present embodiment, the information electrodes are composed of composite electrodes, and the matrix electrodes are driven by the composite electrodes and the scanning electrodes.
[0124]
Specifically, a plurality of pixels including electrophoretic particles movably held by a holding member are provided, and a drive selection voltage is selectively applied through a scanning electrode and an information electrode electrically connected to the pixels. Thus, in the electrophoretic display device that determines the state of each pixel,
A scan drive circuit for supplying a scan signal to the scan electrode,
An information drive circuit for supplying an information signal to the information electrode;
With
The information electrode is a composite electrode composed of first and second sub-information electrodes to which signals are independently applied,
The information drive circuit includes a first information drive circuit and a second information drive circuit connected to the first and second sub information electrodes, respectively.
The drive selection voltage is applied to the pixel by supplying a selection signal to three electrodes of the composite electrode electrically connected thereto, that is, the first and second sub-information electrodes and the scanning electrode. The state of the pixel is changed by being applied.
[0125]
That is, in the configuration of FIG. 10, scan electrode driver C is configured not as scan electrode selector 81 but as a sub information electrode driver that works in cooperation with information electrode driver 13 based on the information electrode from data converter 12. Just fine. The truth table of the operation is the same as that in FIG. 11, and the operation may be performed so as to satisfy this truth table.
[0126]
In addition, it is clear that the first embodiment and the fourth embodiment are combined to form a composite electrode on both the lower substrate and the upper substrate, and that an embodiment in which a four-dimensional matrix drive is performed can be configured. Illustration is omitted.
[0127]
【The invention's effect】
As described above, as in the present invention, at least one of the plurality of scanning electrodes and the information electrode and at least two drive circuits are connected in a matrix, and all of the drive circuits connected to each of the electrodes are provided in a predetermined manner. Since the number of output channels of the drive circuit is reduced by providing a configuration in which the state of the pixel undergoes a predetermined change only when a signal is applied, the total number of pixels of the electrophoretic panel is reduced to a half power. There is no need to provide an output channel for the drive circuit in proportion to Thus, the electrophoretic panel can be driven with a small number of drive IC chips. By such a drastic reduction in the number of drive circuits, mounting of the drive IC chip becomes easy, and at the same time drastic cost reduction becomes possible.
[0128]
In addition, since a plurality of electrode portions in which sub-electrodes are discretely arranged are provided for one pixel, selective application of a drive selection voltage using a three-dimensional matrix can be performed satisfactorily. Further, by insulating the plurality of scan electrodes, power consumption can be reduced as compared with the case where the electrodes are not insulated as in JP-A-2000-56219.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of an embodiment of an electrophoretic display device according to the present invention.
FIG. 2 is a connection diagram illustrating a connection state between a composite electrode and a matrix wiring unit according to the present invention.
FIG. 3 is a diagram illustrating signal waveforms applied to each scanning electrode from two scanning driving circuits in the electrophoretic display device of the present invention.
FIG. 4 is a diagram showing a voltage applied to an information electrode and an electric field strength between the scanning electrode and the information electrode caused by the voltage applied to the information electrode in the electrophoretic display device of the present invention. (A) is a diagram when an ON voltage is applied to the information electrode. (B) is a diagram when an OFF voltage is applied to the information electrode.
FIG. 5 is a timing chart showing signal waveforms applied to each scanning electrode from two scanning driving circuits in the electrophoretic display device of the present invention.
FIG. 6 is a plan view showing a detailed shape of one embodiment of a composite electrode constituting the present invention.
FIG. 7 is a diagram showing a detailed shape of one embodiment of a composite electrode constituting the present invention, and is a diagram when two sub-scanning electrodes are vertically overlapped. (A) is a plan view. (B) is a side view.
FIG. 8 is a view showing a detailed shape of one embodiment of a composite electrode constituting the present invention, and is a view showing another case where two sub-scanning electrodes are vertically overlapped. (A) is a plan view. (B) is a side view.
FIG. 9 is a truth table summarizing the operation states in the first to third embodiments of the present invention.
FIG. 10 is a schematic block diagram of Embodiment 4 of the present invention.
FIG. 11 is a table summarizing operation states according to the fourth embodiment of the present invention.
FIG. 12 is a truth table summarizing the operation status in the conventional example.
13 is a schematic plan view and a cross-sectional view of a pair of comb electrodes of FIG. 6;
FIG. 14 is a schematic cross-sectional view of an embodiment in which the planar arrangement of the electrodes is the same as that of FIG.
FIG. 15 is a schematic cross-sectional view of a form in which two sub-scanning electrodes are formed in a multi-layered form, although the planar arrangement of the electrodes is the same as that of FIG.
FIG. 16 is a schematic cross-sectional view of an embodiment in which the planar arrangement of the electrodes is slightly different from that of FIG.
FIG. 17 is a schematic diagram illustrating a pixel configuration for black display.
FIG. 18 is a schematic diagram illustrating a pixel configuration for white display.
[Explanation of symbols]
11 Data input section
12 Data modulator
13 Information electrode driver
14 Clock generator
15 Scanning electrode selector
16 Scanning electrode driver A
17 Scanning electrode driver B
18 Matrix wiring section
19 Electrophoresis panel
21 1st sub-scanning electrode
22 Second sub-scanning electrode
23 scan electrode group
121 COMA1
122 COMB1
311 Selection signal
312 Non-selection signal
322 composite waveform (drive selection voltage)

Claims (3)

A large number of pixels including electrophoretic particles movably held by a holding body are arranged in a two-dimensional matrix, and an electrophoretic display device that determines a state of each pixel by selectively applying a drive selection voltage to the pixels. At
An electrophoretic display device, wherein three electrodes are electrically connected to the pixel, and a driving circuit that drives the three electrodes in a three-dimensional matrix is provided. Each of the pixels includes a plurality of pixels including electrophoretic particles movably held by a holding member, and selectively applying a drive selection voltage through a scanning electrode and an information electrode electrically connected to the pixels. In an electrophoretic display device for determining a state,
A scan drive circuit for supplying a scan signal to the scan electrode,
An information drive circuit for supplying an information signal to the information electrode;
With
The scanning electrode or the information electrode is a composite electrode composed of first and second sub-electrodes to which signals are independently applied,
The scan drive circuit or the information drive circuit has a first sub-electrode drive circuit and a second sub-electrode drive circuit connected to the first and second sub-electrodes, respectively.
The pixel is driven by a selection signal being supplied to three electrodes, the first and second sub-electrodes of the composite electrode and the information electrode or the scanning electrode, which are electrically connected thereto. An electrophoretic display device in which a selection voltage is applied and the state of the pixel changes. 3. The electrophoretic display device according to claim 1, wherein, of the three electrodes, two electrodes forming a composite electrode each have a plurality of portions discretely provided for one pixel. 4.

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