JP3991367B2 - Electrophoresis device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophoretic apparatus that performs display by applying a voltage between electrodes to move charged pigment particles in a medium sealed between the electrodes.
[0002]
[Prior art]
An electrophoretic display device 2 as shown in FIG. 6A has been developed. This electrophoretic display device has two substrates 4a and 4b, at least one of which is translucent. These substrates are made of glass substrates, for example. The substrates 4a and 4b are opposed to each other with a predetermined interval through the partition wall 6, and the substrates 4a and 4b and the partition wall 6 constitute a closed space. Flat transparent electrodes 8a and 8b are mounted on the opposing inner surfaces of these substrates 4a and 4b.
[0003]
In the sealed space between the two substrates 4a and 4b, the electrophoretic display dispersion 10 is sealed. The electrophoretic display dispersion liquid 10 includes, for example, a colored dispersion medium 10 a colored in black, and charged white pigment particles 10 b dispersed in the dispersion medium 10.
[0004]
When the electrophoretic display device 2 applies a positive voltage to the upper electrode and a negative voltage to the lower electrode between the electrodes 8a and 8b, for example, as shown in FIG. The negatively charged white pigment particles 10b dispersed in the medium are electrophoresed toward the anode by Coulomb force, and the white pigment particles 10b adhere to the upper anode electrode 8a. When the electrophoretic display device in such a state is observed from the position of the eye as shown in FIG. 6B, the portion where the white pigment particles adhere to form a layer is the transparent electrode 8a and the transparent glass substrate 4a. It will appear white through.
[0005]
On the other hand, when the polarity of the applied voltage is reversed, as shown in FIG. 6C, the white pigment particles adhere to the electrode on the opposite side to form a layer, and when observed from the position shown in the figure, the white pigment Since the particle layer is hidden behind the black dispersion medium, the electrophoretic display panel appears black.
[0006]
In the electrophoretic display device based on such a principle, it is necessary to keep applying the driving voltage while the colored pigment particles move. If the application time is short, the colored pigment particles cannot reach the electrode, resulting in a decrease in display contrast. For this reason, conventionally, the drive voltage is generally applied for several tens of milliseconds to several hundreds of milliseconds. The moving speed of the pigment particles, that is, the display changing speed is proportional to the driving voltage.
[0007]
Even when the application of the drive voltage is stopped, the white pigment particle layer attached to the electrode maintains its attached state due to the intermolecular attractive force. For this reason, once the white pigment particle layer has adhered to the electrode, it is not necessary to apply a voltage in particular except for periodically applying a voltage for maintaining the adhesion state. An electrophoretic display configured to periodically apply a driving voltage to maintain the attached state is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-213827.
[0008]
[Problems to be solved by the invention]
By the way, when the pigment particles are in contact with one of the electrodes, the particles are attracted to the electrode surface by intermolecular attractive force, and a high driving voltage is required to change the display state by separating the particles. If this driving voltage is too low, particles remain on the electrode surface, leading to a decrease in contrast or display quality. However, if the drive voltage is set too high, it is necessary to continue applying the drive voltage for several tens of milliseconds to several hundreds of milliseconds as described above, so that the deterioration of the dispersion is accelerated and the life of the display device is shortened. There is a problem of causing a decrease. Specific examples of the deterioration of the dispersion include generation of bubbles due to electrolysis of moisture in the dispersion.
[0009]
Therefore, conventionally, when emphasizing the display quality of the electrophoretic display device, the drive voltage is set to a high level of about 70 to 100 V, and when the durability is more important than the display quality, the drive voltage is set to a lower value. Was.
The present invention has been made in view of such a situation, and an object thereof is to provide an electrophoretic device that does not cause deterioration of a dispersion, has excellent durability, and has improved contrast and display quality.
[0010]
In order to solve the above problem, a first electrophoresis apparatus according to the present invention includes a first electrode, a second electrode, a dispersion liquid in which pigment particles are dispersed in a colored dispersion medium, and the first electrode. Driving voltage generating means for applying a driving voltage between the electrode and the second electrode to cause the pigment particles to electrophores, wherein the driving voltage generating means is configured such that the pigment particles are the same as those of the first electrode. A first driving voltage is applied to separate the first driving voltage, and a second driving voltage for completely moving from the first electrode side to the second electrode side after applying the first driving voltage. The driving voltage is applied, and the absolute value of the voltage value of the first driving voltage is larger than the absolute value of the voltage value of the second driving voltage, and the first driving voltage is The application time is shorter than the application time of the second drive voltage, and the voltage value of the second drive voltage is It is characterized in that the electrolysis of the dispersion is a level that does not occur.
The second electrophoresis apparatus of the present invention includes a first electrode, a second electrode, a dispersion liquid in which pigment particles are dispersed in a colored dispersion medium, and a first voltage that generates a first driving voltage. A generator, a second voltage generator for generating a second drive voltage, a first switch, and a second switch, the first electrode side to the second electrode side The first driving voltage is applied to the dispersion by turning on the first switch during the first period when the pigment particles are moved to the second period, and the second period after the first period. The second switch is turned on to apply the second drive voltage to the dispersion, the second switch is turned off to end the second period, and the pigment particles are moved to the second It is characterized by maintaining the state of being attached and unevenly distributed on the electrode side.
In the electrophoretic device, the first drive voltage is applied to separate the first drive voltage from the first electrode side, and the second drive voltage is applied from the first electrode side to the second electrode side. It is characterized by applying in order to move completely.
In the above electrophoretic device, it is preferable that the time for applying the first drive voltage is shorter than the time for applying the second drive voltage.
In the electrophoretic device, it is preferable that the voltage value of the second drive voltage is a level at which electrolysis of the dispersion does not occur.
In the electrophoretic device, it is preferable that the absolute value of the voltage value of the first drive voltage is larger than the absolute value of the voltage value of the second drive voltage.
[0011]
In the present invention, the absolute value of the high-level driving voltage is determined according to the type of the dispersion liquid and is not particularly limited, but is, for example, 70 to 100V. The application time of the high level driving voltage is preferably as short as possible from the viewpoint of preventing the deterioration of the dispersion, but if it is too short, the pigment particles cannot be separated from the electrode, so 1 to 20 milliseconds, preferably several milliseconds. Degree.
[0012]
The absolute value of the low-level driving voltage is determined according to the type of the dispersion liquid and is not particularly limited, but is, for example, 30 to 50V. When the driving voltage is 30 V or less, the electrophoresis phenomenon tends to be difficult to occur. When the driving voltage is 50 V or more, the durability is difficult, so the above range is preferable. The application time of the low-level driving voltage is preferably the time until the pigment particles complete the movement from one electrode to the other electrode, specifically, several tens of milliseconds to several hundreds of milliseconds. It is preferable.
[0013]
The present inventor has completed the present invention by paying attention to the fact that the maximum driving voltage is required when the pigment particles are slightly separated from the electrode surface, and the intermolecular force decreases dramatically after being slightly separated. I came to let you. That is, in the electrophoretic display device according to the present invention, the high level driving voltage is applied only for the time necessary to slightly separate the pigment particles, the remaining adhesion of the pigment particles is prevented, and then electrolysis does not occur. In addition, the low level driving voltage is continuously applied for the time during which the particles are completely moved.
[0014]
Therefore, according to the electrophoretic display device according to the present invention, the deterioration of the dispersion liquid is not caused by the driving voltage, the durability of the device is improved, and the adhesion residue of the pigment particles is eliminated, and the contrast and the display quality are improved. Can be improved. That is, according to the present invention, it is possible to simultaneously satisfy conflicting requests that could not be made in the past.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electrophoretic display device according to the present invention will be described in detail based on embodiments shown in the drawings.
First embodiment Fig. 1A is a schematic cross-sectional view of an electrophoretic display device according to an embodiment of the present invention, and Fig. 1B is a drive of the drive voltage generator shown in Fig. 1A. It is a figure which shows a voltage waveform.
[0016]
As shown in FIG. 1A, an electrophoretic display device 20 according to an embodiment of the present invention includes a first substrate 22 and a second substrate 24, and keeps the substrates 22 and 24 at a predetermined interval. A partition wall 30 is mounted around the substrates 22 and 24.
The first substrate 22 is made of a light transmissive plate such as transparent glass, for example. A first electrode 26 is formed on the surface of the first substrate 22 facing the second substrate 24. The first electrode 26 is made of, for example, an indium tin oxide (ITO) film. The first electrode 26 is formed over the entire display screen of the first substrate 22, and a mask having a certain light transmission pattern (display pattern) formed on the surface thereof is attached. Alternatively, the first electrode 26 may be attached to the surface of the first substrate 22 in a desired pattern according to the display pattern.
[0017]
The second substrate 24 is not necessarily transparent, but is made of, for example, a glass substrate. A second electrode 28 is formed on the surface of the second substrate 24 facing the first substrate. The second electrode 28 is not necessarily a transparent electrode, but is made of, for example, an ITO film.
[0018]
The partition wall 30 that holds the first substrate 22 and the second substrate 24 at a predetermined interval also has a function of sealing a sealed space formed between the substrates 22 and 24 and the partition wall 30, such as an epoxy resin. It is composed of a sealant. The thickness (interelectrode distance) of the partition wall 30 is usually about 20 μm to 1 mm.
[0019]
An electrophoretic display dispersion liquid 10 is accommodated in a sealed space formed between the two substrates 22 and 24 and the partition wall 30. The electrophoretic display dispersion liquid 10 includes a colored dispersion medium 10a and the dispersion liquid 10a. It includes charged pigment particles 10b dispersed in a dispersion medium. Although it does not specifically limit as the colored dispersion medium 10a, For example, it is a black dispersion medium, Specifically, a hexylbenzene + anthraquinone type dye etc. are illustrated. The pigment particles 10b are not particularly limited. For example, white pigment particles or other colored pigment particles are used. Specifically, the outer diameter is about 0.8 to 1.2 μm to which a surfactant is added. Examples thereof include zinc sulfide (ZnS) particles.
[0020]
In the present embodiment, a drive voltage generator 32 is connected between the first electrode 26 and the second electrode 28. For example, the drive voltage generator 32 generates a drive voltage having a drive voltage waveform shown in FIG. As shown in FIG. 1B, this drive voltage is composed of a high level drive voltage Vh for a relatively short time and a low level drive voltage Vl generated subsequently. In this embodiment, the voltage value of the high level drive voltage Vh is about 70 to 100 V, and the application time Th is about several milliseconds. In this embodiment, the voltage value of the low level drive voltage Vl is about 30 to 50 V, and the application time Tl is about several tens of milliseconds to several hundreds of milliseconds.
[0021]
In the electrophoretic display device 20 according to this embodiment, the high-level driving voltage Vh is applied for a time necessary to slightly separate the pigment particles 10b shown in FIG. 1 from the one second electrode 28, and the pigment particles 10b. Thereafter, the particles 10b are completely moved from the second electrode 28 to the first electrode 26 to such an extent that the electrophoretic display dispersion 10 is not electrolyzed. Continue applying for time. As a result, almost all of the pigment particles 10b are separated from the surface of the second electrode 28 and adhere to the first electrode 26 side, and the adhesion residue of the pigment particles 10b on the second electrode 28 can be prevented. Further, since the low level driving voltage Vl is low enough not to electrolyze the dispersion 10, the dispersion does not deteriorate. When the pigment particles 10b move to the first electrode 26 side, the display surface of the first substrate 22 is colored by the pigment particles 10b, and a predetermined display screen is displayed.
[0022]
In order to separate the pigment particles 10b from the other first electrode 26 and to direct the pigment particles 10b toward the second electrode 28, the drive voltage generator 32 has the same drive waveform as that shown in FIG. However, a different driving voltage may be applied between the electrodes 26 and 28. Then, in the same manner as described above, almost all of the pigment particles 10 b are separated from the first electrode 26 and adhere to the second electrode 28, and the first electrode 26 has no remaining adhesion of the pigment particles 10 b. As a result, on the display surface of the first substrate 22, the pigment particles 10b are hidden by the shadow of the dispersion medium 10a and become colored by the dispersion medium 10a, resulting in a display state different from the above.
[0023]
Therefore, according to the electrophoretic display device 20 according to the present embodiment, the drive voltage does not cause the dispersion 10 to be deteriorated, the durability of the device 20 is improved, and the pigment particles 10b are not attached. Contrast and display quality can be improved.
[0024]
Second Embodiment FIG. 2 is a plan view showing an example of a display screen of an electrophoretic display device according to another embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 4A is a block diagram showing an example of the drive voltage generating circuit shown in FIG. 3, FIG. 4B is a time chart showing the operation timing of the circuit shown in FIG. 4A, and FIG. 5 is shown in FIG. It is a time chart figure which shows the drive waveform for displaying 0 and 1 on the screen to show.
[0025]
As shown in FIGS. 2 and 3, the electrophoretic display device 20a according to the second embodiment of the present invention includes a first substrate 22a and a second substrate 24a, and keeps the substrates 22a and 24a at a predetermined interval. A partition wall 30a is mounted around the substrates 22a and 24a.
[0026]
The first substrate 22a is made of a light transmissive plate such as transparent glass, for example. A first electrode 26a is formed on the surface of the first substrate 22a facing the second substrate 24a. The first electrode 26a is made of, for example, an indium tin oxide (ITO) film. The first electrode 26a is formed over the entire display screen of the first substrate 22a, functions as a common electrode, and is grounded. On the surface of the first electrode 26a, a light shielding mask 40 having a light transmission pattern 42 (display pattern) for displaying numbers 0 to 9 is formed. The light transmission pattern 42 formed on the light shielding mask 40 is such that only this portion can transmit light. In order to display numbers 0 to 9, seven long holes are arranged in an 8-shape. The pattern has been changed.
[0027]
The second substrate 24a is not necessarily transparent, but is made of, for example, a glass substrate. In addition, second electrodes 28a to 28g are formed on the surface of the second substrate 24a facing the first substrate. The second electrodes 28a to 28g are not necessarily transparent electrodes, but are made of, for example, an ITO film. In the present embodiment, these second electrodes 28a to 28g function as segment electrodes, and are formed separately in a pattern that includes each pattern corresponding to the elongated hole-shaped light transmission pattern 42. is there.
[0028]
The partition wall 30a that holds the first substrate 22a and the second substrate 24a at a predetermined interval also has a function of sealing a sealed space formed between the substrates 22a and 24a and the partition wall 30a. Consists of sealant. The thickness (distance between electrodes) of the partition wall 30a is usually about 20 μm to 1 mm.
[0029]
An electrophoretic display dispersion liquid 10 is accommodated in a sealed space formed between the two substrates 22a and 24a and the partition wall 30a. The electrophoretic display dispersion liquid 10 includes a colored dispersion medium 10a and the dispersion liquid 10a. It includes charged pigment particles 10b dispersed in a dispersion medium. Although it does not specifically limit as the colored dispersion medium 10a, For example, it is a black dispersion medium, Specifically, a hexylbenzene + anthraquinone type dye etc. are illustrated. The pigment particles 10b are not particularly limited. For example, white pigment particles or other colored pigment particles are used. Specifically, the outer diameter is about 0.8 to 1.2 μm to which a surfactant is added. Examples thereof include zinc sulfide (ZnS) particles.
[0030]
In the present embodiment, a drive voltage is applied to each of the electrodes 28a to 28g serving as segment electrodes independently from the electrode selection circuit 44 shown in FIG. The electrode selection circuit 44 is connected to a positive drive voltage generation circuit 32a, a negative drive voltage generation circuit 32b, and a display data control unit 46. The display data control unit 46 is connected to an input means such as a keyboard or a numeric keypad. For example, display data is input from the display data control unit 46, controls the electrode selection circuit 44, and performs a desired display on the display screen of the display device 20a. It is like that.
[0031]
The positive drive voltage generation circuit 32a and the negative drive voltage generation circuit 32b are different only in whether the drive voltage is positive or negative, and the drive waveforms of the drive voltage output therefrom have the same absolute value. The waveform of the drive voltage shown in 1 (B) is output. The drive voltage is selectively applied by the electrode selection circuit 44 to any one of the second electrodes 28a to 28g that are segment electrodes.
[0032]
The positive drive voltage generation circuit 32a and the negative drive voltage generation circuit 32b have a circuit configuration shown in FIG. 4A, for example, and include a high voltage generation unit 48, a low voltage generation unit 50, a control unit 52, and switches 53 and 54. And have. The high voltage generator 48 generates a high level drive voltage Vh shown in FIG. The low voltage generator 50 generates a low level drive voltage Vl shown in FIG. These voltages are switched by switching the switches 53 and 54 by the control unit 52. That is, as shown in FIG. 4B, the switch 53 is first turned on, and after a short time Th, the switch 53 is turned off and the switch 54 is turned on. As a result, a relatively short high-level driving voltage Vh shown in FIG. 1B is obtained. Next, the voltage from the low voltage generator 50 is applied to the electrode selection circuit 44 until the switch 54 is turned off after the time Tl. As a result, the low level drive voltage Vl shown in FIG. 1B can be obtained following the drive voltage Vh.
[0033]
Next, using the electrophoretic display device 20a shown in FIGS. 2 to 4, a specific waveform of the drive voltage when, for example, 0 is displayed on the display screen of the first substrate 22a and then 1 is displayed will be described. .
As shown in FIG. 5A, in order to display 0 on the display screen, a positive drive voltage of the drive waveform shown in FIG. 1B is applied to the second electrodes 28a to 28f serving as segment electrodes, Only the second electrode 28g is applied with a negative drive voltage that is opposite in polarity to the drive voltage and has the same absolute value. As a result, the pigment particles 10b move from the second electrodes 28a to 28f to the first electrode 26a, which is the common electrode, without adhering only to the portion located in the pattern 42 corresponding to 0 shown in FIG. 0 is displayed by coloring 10b.
[0034]
Next, when the display of 0 is changed to the display of 1, as shown in FIG. 5B, the second electrodes 28a and 28b serving as the segment electrodes are positive in the drive waveform shown in FIG. The drive voltage is continuously applied, and the second electrodes 28c to 28f are switched from positive to negative drive voltages. Further, a negative drive voltage is applied again to the second electrode 28g. As a result, in the second electrodes 28c to 28f that are segment electrodes, the positive driving voltage is switched to the negative driving voltage, and the pigment particles 10b corresponding to the electrode portions are separated from the first electrode 26a, and the second electrode 28a. Move by electrophoresis. At that time, since the high-level driving voltage -Vh is first applied, the pigment particles 10b are separated from the first electrode 26a side without the pigment particles remaining attached. The low level driving voltage Vl applied thereafter is a low level that does not cause electrolysis in the dispersion liquid 10, and this voltage completely moves the particle 10b from the first electrode 26a side to the second electrode 28a side. Until it is applied.
[0035]
As a result, the pigment particles 10b remain only in the portions located in the pattern 42 (shaded portions in FIG. 2) corresponding to the second electrodes 28a and 28b, and the other particles move toward the second electrodes 28c to 28g, 1 is displayed by coloring the particle 10b.
In the electrophoretic display device 20b according to the present embodiment, the high level driving voltage -Vh is applied only for a time necessary for slightly separating the pigment particles 10b shown in FIG. 3 from the first electrode 26a, and the pigment particles 10b are applied. After that, the low level driving voltage −Vl is applied so that the electrophoretic display dispersion liquid 10 is not electrolyzed, and the particles 10b are completely transferred from the first electrode 26a to the second electrode 28a. Continue applying for the time to move. As a result, in the corresponding electrode, almost all of the pigment particles 10b are separated from the surface of the first electrode 26a and adhere to the second electrode 28a side, thereby preventing the pigment particles 10b from remaining on the first electrode 28a. Can do. Further, since the low level driving voltage Vl is low enough not to electrolyze the dispersion 10, the dispersion does not deteriorate.
[0036]
When other numbers are displayed on the display screen shown in FIG. 2, a desired second electrode is supplied from the positive drive voltage generation circuit 32a or the negative drive voltage generation circuit 32b shown in FIG. Any positive driving voltage or negative driving voltage shown in FIG. 1B may be applied to 28a to 28g.
[0037]
According to the electrophoretic display device 20a according to the present embodiment, the dispersion liquid 10 is not caused to deteriorate by the driving voltage, the durability of the device 20a is improved, and the adhesion residue of the pigment particles 10b is also eliminated. Display quality can be improved.
[0038]
The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.
For example, the image displayed on the display screen of the electrophoretic display device is not limited to the above-described embodiment. By changing the shape and arrangement of the light transmission pattern 42 of the mask 40 shown in FIGS. 2 and 3, and changing the shape, the number of arrangement, the arrangement pattern, and the like of the second electrodes 28a to 28g that are segment electrodes, An image can be displayed.
[0039]
In addition, the color and material of the pigment particles 10b and the dispersion medium 10a in the dispersion 10 can be variously modified.
[0040]
【The invention's effect】
As described above, according to the electrophoresis apparatus according to the present invention, the deterioration of the dispersion liquid is not caused by the driving voltage, the durability of the apparatus is improved, the adhesion of the pigment particles is eliminated, and the contrast is increased. And display quality can be improved. That is, according to the present invention, it is possible to simultaneously satisfy conflicting requests that could not be made in the past.
[Brief description of the drawings]
FIG. 1A is a schematic cross-sectional view of an electrophoretic display device according to an embodiment of the present invention, and FIG. 1B shows a drive voltage waveform of the drive voltage generator shown in FIG. FIG.
FIG. 2 is a plan view showing an example of a display screen of an electrophoretic display device according to another embodiment of the present invention.
3 is a cross-sectional view taken along line III-III shown in FIG.
4A is a block diagram illustrating an example of the drive voltage generation circuit illustrated in FIG. 3, and FIG. 4B is a time chart illustrating the operation timing of the circuit illustrated in FIG. 4A.
FIG. 5 is a time chart showing drive waveforms for displaying 0 and 1 on the screen shown in FIG. 2;
6A to 6C are schematic views showing the principle of an electrophoretic display device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Dispersion liquid 10a ... Dispersion medium 10b ... Pigment particle 20, 20a ... Electrophoretic display device 22, 22a ... 1st board | substrate 24, 24a ... 2nd board | substrate 26, 26a ... 1st electrode 28, 28a-28g ... 2nd electrode DESCRIPTION OF SYMBOLS 30 ... Partition 32 ... Drive voltage generator 32a ... Positive drive voltage generator 32b ... Negative drive voltage generator 40 ... Light-shielding mask 42 ... Light-transmitting pattern 44 ... Electrode selection circuit 46 ... Display data control part

Claims (8)

A first electrode;
A second electrode;
A dispersion in which pigment particles are dispersed in a colored dispersion medium;
Drive voltage generating means for applying a drive voltage between the first electrode and the second electrode to cause electrophoresis of the pigment particles;
The drive voltage generating means applies a first drive voltage to separate the pigment particles from the first electrode side;
After applying the first driving voltage, applying a second driving voltage for moving completely from the first electrode side to the second electrode side,
The absolute value of the voltage value of the first drive voltage is greater than the absolute value of the voltage value of the second drive voltage;
An electrophoresis apparatus characterized by the above. The electrophoresis apparatus according to claim 1,
The time for applying the first drive voltage is shorter than the time for applying the second drive voltage;
An electrophoresis apparatus characterized by the above. The electrophoresis apparatus according to claim 1 or 2,
The voltage value of the second driving voltage is a level at which electrolysis of the dispersion does not occur. A first electrode;
A second electrode;
A dispersion in which pigment particles are dispersed in a colored dispersion medium;
A first voltage generator for generating a first drive voltage;
A second voltage generator for generating a second drive voltage;
A first switch;
A second switch,
When the pigment particles are moved from the first electrode side to the second electrode side, the first drive voltage is applied to the dispersion by turning on the first switch during a first period. Applied,
Applying the second drive voltage to the dispersion by turning on the second switch in a second period after the first period;
Turning off the second switch to end the second period and maintaining the pigment particles attached and unevenly distributed on the second electrode side;
An electrophoresis apparatus characterized by the above. The electrophoresis apparatus according to claim 4,
Applying the first drive voltage to separate from the first electrode side;
Applying the second drive voltage to completely move from the first electrode side to the second electrode side;
An electrophoresis apparatus characterized by the above. The electrophoresis apparatus according to claim 4 or 5,
The time for applying the first drive voltage is shorter than the time for applying the second drive voltage;
An electrophoresis apparatus characterized by the above. The electrophoresis apparatus according to any one of claims 4 to 6,
The voltage value of the second drive voltage is a level at which electrolysis of the dispersion does not occur;
An electrophoresis apparatus characterized by the above. The electrophoresis apparatus according to any one of claims 4 to 7,
The absolute value of the voltage value of the first drive voltage is greater than the absolute value of the voltage value of the second drive voltage;
An electrophoresis apparatus characterized by the above.

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