JP2009229831A - Electrophoretic display device and its driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophoretic display device and its driving method for maintaining satisfactory quality of display irrespective of infiltration of water. <P>SOLUTION: The electrophoretic display device includes a first substrate 2 provided with a plurality of pixel electrodes, a second substrate 3 arranged by opposing to the first substrate 2, an electrophoretic material layer 4 sealed in a space between the first substrate 2 and the second substrate 3, and a sealing material 5 for sealing the first substrate 2 and the second substrate 3 in peripheral fringe parts. The electrophoretic display device further includes: a plurality of humidity sensors 6 for main measurement for detecting water content in the space; a humidity sensor 7 for auxiliary measurement; and a control means for obtaining distribution of water content in the space from the information about water content detected by these humidity sensors 6, 7 and controlling driving voltage to be applied on the electrophoretic material layer 4 in accordance with a position in a display region based on the distribution of water content. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophoretic display device and a method for driving the same, and more particularly to a configuration of an electrophoretic display device that can maintain display quality even when a certain amount of moisture enters the inside.

  In recent years, electrophoretic displays have attracted attention as electronic paper displays, and now occupy most electronic paper displays on the market. As shown in FIG. 7, the electrophoretic display encloses a dispersion medium 101, positively charged black particles 102, and negatively charged white particles 103 in a microcapsule 100, and a transparent common electrode 104. An image is displayed by attracting one of the particles to the common electrode 104 side (viewing side) due to a potential difference between the pixel electrode 105 and the pixel electrode 105. In the electrophoretic display, the state of the particles is maintained even if the potential difference between the electrodes is eliminated after the particles are moved, so that the electrophoretic display is used as an electronic paper display having memory properties.

As described above, in an electrophoretic display, a large number of microcapsules are sandwiched between a pair of substrates each having a pixel electrode and a common electrode formed thereon. For example, when the sealing between the pair of substrates is not sufficient and moisture enters the microcapsule, display deterioration such as a contrast decrease occurs from the peripheral portion of the display area 107 of the electrophoretic display body 106 as shown in FIG. It has been found that the area in which the contrast has decreased (denoted by reference numeral 108) reduces the display quality. Therefore, an electrophoretic display device in which a pair of substrates is formed of a transparent composite film of a transparent resin film layer and a transparent inorganic thin film layer has been proposed (see Patent Document 1). According to this Patent Document 1, it is described that the use of the transparent composite film can suppress moisture permeability and organic solvent permeability to be low, so that reliability is improved.
JP 2003-202603 A

  When using a film with low moisture permeability as in Patent Document 1, it is necessary to completely seal the ends of the bonded films. However, no matter how much the low moisture-permeable film is used, if the sealing part deteriorates over time or if the sealing performance is exceeded, such as when it is accidentally dropped in water, Intrusion of moisture into the electrophoretic material is unavoidable, and there is still a problem that display quality is deteriorated.

  The present invention has been made in order to solve the above-described problems, and an object thereof is to provide an electrophoretic display device capable of maintaining display quality even when moisture enters and a driving method thereof. .

  In order to achieve the above object, an electrophoretic display device according to the present invention includes a first substrate provided with a plurality of pixel electrodes, a second substrate disposed opposite to the first substrate, and the first substrate. An electrophoretic display device comprising: an electrophoretic material layer sealed in a space between the second substrate; and a sealing material that seals the first substrate and the second substrate at a peripheral edge. A plurality of humidity sensors for detecting the amount of moisture in the space, and a moisture amount distribution in the space from the moisture amount information detected by the plurality of humidity sensors, and based on the moisture amount distribution, Control means for controlling a driving voltage applied to the electrophoretic material layer according to the position.

  In order to maintain the display quality of the electrophoretic display device, the inventors of the present application are not based on the idea of preventing the ingress of moisture by structurally contriving the device, but if there is a limit to preventing the ingress of moisture. For example, the present inventors have conceived that display quality can be maintained by accurately detecting that water has entered and adjusting the behavior of the electrophoretic material layer due to the ingress of water with a driving voltage, and have reached the present invention. In particular, in the configuration of the present invention, the moisture amount is not detected at only one point in the space between the first substrate and the second substrate, but the moisture amount distribution in the space is obtained from moisture amount information obtained from a plurality of humidity sensors. The driving voltage applied to the electrophoretic material layer is controlled according to the position in the display region based on the moisture content distribution. As a result, the drive voltage at various locations in the display area can be appropriately controlled according to the state and degree of moisture permeation at that time, so that the display quality of the entire display area can be sufficiently maintained.

In the electrophoretic display device of the present invention, the plurality of humidity sensors may be arranged at intervals in a direction along the outer circumferences of the first substrate and the second substrate.
According to this configuration, for example, when moisture enters due to deterioration of the sealing portion that seals two substrates at the outer peripheral portion, the moisture intrusion is performed by the plurality of humidity sensors arranged along the outer periphery. It can be detected reliably. Therefore, the drive voltage can be adjusted with higher accuracy at an earlier stage.

In the electrophoretic display device according to the aspect of the invention, the plurality of humidity sensors may include a plurality of first humidity sensors disposed on peripheral portions of the first substrate and the second substrate, and the first humidity sensor than the first humidity sensor. It can be set as the structure which has a some 2nd humidity sensor arrange | positioned near the center part of the board | substrate and the said 2nd board | substrate.
According to this configuration, after detecting the amount of moisture intrusion by the plurality of first humidity sensors arranged near the peripheral edge as the first stage, the plurality of second humidity sensors arranged near the center as the second stage. It is possible to detect information such as the progress and spread of moisture intrusion. In this way, it is possible to know a more accurate and fine moisture distribution, and to appropriately control the drive voltage.

In the electrophoretic display device of the present invention, the plurality of first humidity sensors may be provided inside the sealing material.
As described above, there are many cases where water enters from the sealing material as the water intrusion route. However, it is possible to detect water intrusion earliest by providing a plurality of first humidity sensors inside the sealing material. it can. In addition, since the first humidity sensor can be fixed together with a sealing material that seals between the two substrates, it is not necessary to prepare a fixing structure for fixing the first humidity sensor separately, and the structure is simple. .

In the electrophoretic display device of the present invention, the plurality of second humidity sensors may be provided on a surface of the first substrate opposite to the viewing side.
Since the plurality of second humidity sensors need to be installed closer to the center of the substrate, there is a sufficient possibility that they are located inside the display area. Still, if a plurality of second humidity sensors are provided on the surface of the first substrate on the side opposite to the viewing side, the visual recognition of the display is not hindered, and a device structure suitable for the present invention is provided. it can.

In the electrophoretic display device according to the aspect of the invention, the control unit may control the driving voltage in the divided area according to the moisture distribution for each divided area obtained by dividing the display area.
For example, it is ideal if the drive voltage can be controlled for each pixel arranged in a matrix that forms the display area, but this is not practical. On the other hand, according to the above configuration, the driving voltage in the divided area may be controlled according to the moisture amount distribution for each divided area obtained by dividing the display area. Therefore, a finite number of humidity sensors are used. If a certain amount of moisture distribution is grasped, the drive voltage can be adjusted enough to maintain the display quality.

In the electrophoretic display device according to the aspect of the invention, in the divided area where the humidity sensor is not arranged, the control unit interpolates moisture amount information in a neighboring divided area where the humidity sensor is arranged to obtain a moisture amount. It can be set as the structure which estimates and calculates | requires the said moisture content distribution.
According to this configuration, since the amount of moisture can be estimated even in a divided area where no humidity sensor is arranged, it is possible to detect a fine moisture amount distribution without increasing the number of humidity sensors.

In the electrophoretic display device according to the aspect of the invention, the control unit obtains the moisture amount distribution using moisture amount information before and after a predetermined time detected by at least one humidity sensor among the plurality of humidity sensors. be able to.
According to this configuration, since the trend of moisture content can be estimated from moisture content information before and after a predetermined time in an arbitrary humidity sensor, it is possible to detect a fine moisture content distribution without increasing the number of humidity sensors. it can.

In the electrophoretic display device according to the aspect of the invention, the control unit includes a storage unit that stores a lookup table in which a moisture amount in the space is associated with an optimum driving voltage corresponding to the moisture amount. The drive voltage can be determined based on a table.
According to this configuration, the drive voltage can be determined without performing complicated calculations, so that the configuration of the control means can be simplified.

In the electrophoretic display device according to the aspect of the invention, the control unit issues a warning signal when a moisture amount detected by at least one humidity sensor among the plurality of humidity sensors exceeds a maximum moisture amount that can be voltage controlled. It can be.
According to this configuration, it is possible to warn the user that the amount of moisture that has entered exceeds the range in which voltage control is possible, and for example, it is possible to take measures such as repairing the user at an early stage.

An electrophoretic display device driving method according to the present invention includes: a first substrate provided with a plurality of pixel electrodes; a second substrate disposed opposite to the first substrate; and the first substrate and the second substrate. An electrophoretic display device comprising: an electrophoretic material layer enclosed in a space between; and a sealing material that seals the first substrate and the second substrate at a peripheral edge portion. Obtaining a moisture content distribution in the space from a plurality of moisture content information at each point, and controlling a driving voltage applied to the electrophoretic material layer according to a position in a display region based on the moisture content distribution. It is characterized by.
According to this configuration, the drive voltage at various places in the display area can be appropriately controlled in accordance with the state and degree of moisture penetration, so that display quality can be sufficiently maintained.

Hereinafter, an electrophoretic display device according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a plan view of the electrophoretic display device of this embodiment. FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. FIG. 3 is a block diagram showing a configuration of a control unit of the electrophoretic display device. FIG. 4 is a flowchart for explaining the operation of the control unit. FIG. 5 is a diagram showing an example of a moisture content distribution when moisture enters the electrophoretic display device.
In the following drawings, the scale of each member may be appropriately changed in order to make the components easy to see.

  As shown in FIG. 2, the electrophoretic display body 1 of the present embodiment is enclosed in a space between the first substrate 2 and the second substrate 3 that are arranged to face each other and between the first substrate 2 and the second substrate 3. Electrophoretic material layer 4, sealing material 5 that seals the first substrate 2 and the second substrate 3 at the periphery, a main measurement humidity sensor 6 (first humidity sensor), and an auxiliary measurement humidity sensor 7. (Second humidity sensor) and a housing 8. A plurality of pixel electrodes (not shown) are formed on the surface of the first substrate 2 on the electrophoretic material layer 4 side, and a common electrode (not shown) is formed on the surface of the second substrate 3 on the electrophoretic material layer 4 side. Has been. The electrophoretic material layer 4 is formed by planarly arranging a plurality of microcapsules 9 enclosing electrophoretic particles therein. The electrophoretic display 1 of the present embodiment has a configuration in which an image formed by the electrophoretic material layer 4 is viewed from the second substrate 3 side.

  The first substrate 2 is, for example, a plate having a rectangular shape in a plan view made of glass, plastic, or the like, and is not necessarily transparent because it is disposed on the side opposite to the viewing side. A plurality of pixel electrodes for applying a voltage to the electrophoretic material layer 4 are formed in a matrix on the surface of the first substrate 2 on the side of the electrophoretic material layer 4. Data lines, scanning lines, and the like are formed. The pixel electrode is formed of a material obtained by performing nickel plating and gold plating on a Cu (copper) foil in this order, or a material such as Al (aluminum) or ITO (indium tin oxide).

  The second substrate 3 is a plate having a rectangular shape in a plan view made of, for example, plastic, and is disposed on the viewing side. Therefore, it is necessary to use a transparent substrate. A common electrode is formed on the surface of the first substrate 3 on the electrophoretic material layer 4 side, and a voltage is applied to the electrophoretic material layer 4 in cooperation with the pixel electrode on the first substrate 2. The common electrode is a transparent electrode formed from a material such as MgAg (magnesium silver), ITO, or IZO (indium zinc oxide). In the present embodiment, a low moisture-permeable sheet is used as the second substrate 3, and moisture permeation from the surface of the second substrate 3 is suppressed.

  The electrophoretic material layer 4 is obtained by integrating a plurality of microcapsules 9 into a sheet shape with an adhesive. Each microcapsule 9 has a particle diameter of about 30 to 50 μm, for example, and is a spherical body in which a dispersion medium 10, a plurality of white particles 11, and a plurality of black particles 12 are enclosed inside the capsule. The electrophoretic material layer 4 is sandwiched between the pixel electrode and the common electrode, and one or a plurality of microcapsules 9 are disposed in one pixel.

  The outer shell portion (wall film) of the microcapsule 9 is formed using a translucent polymer resin such as acrylic resin such as polymethyl methacrylate and polyethyl methacrylate, urea resin, and gum arabic. The dispersion medium 10 is a liquid that disperses the white particles 11 and the black particles 12 in the microcapsules 9. As the dispersion medium 10, for example, water, alcohol solvents (methanol, ethanol, isopropanol, butanol, octanol, methyl cellosolve, etc.), esters, ketones, and the like can be used. These substances can be used alone or as a mixture, and a surfactant or the like may be further added.

  The white particles 11 are particles (polymer or colloid) made of a white pigment such as titanium dioxide, zinc white, and antimony trioxide, and are used, for example, by being negatively charged. The black particles 12 are particles (polymer or colloid) made of a black pigment such as aniline black or carbon black, and are used by being charged positively, for example. If necessary, these pigments can be appropriately added with a charge control agent composed of an electrolyte, a surfactant and the like, a dispersant, a lubricant, a stabilizer and the like. Further, for example, pigments such as red, green, and blue may be used instead of black particles and white particles. In this case, red, green, blue, etc. can be displayed.

  The sealing material 5 is made of, for example, a resin material such as a UV curable resin or a thermosetting resin, and is provided in a rectangular ring shape along each side of the first substrate 2 and the second substrate 3. The sealing material 5 serves to seal the space in which the electrophoretic material layer 4 is disposed while the first substrate 2 and the second substrate 3 are bonded together at the periphery. Further, as will be described later, a main measurement humidity sensor 6 and an auxiliary measurement humidity sensor 7 are embedded in the sealing material 5.

  As shown in FIG. 1, there are a plurality of main measurement humidity sensors 6 along each side of the first substrate 2 and the second substrate 3 (total 12 in this embodiment, five in the long side direction, short sides). 3 in the direction) are arranged at predetermined intervals. As shown in FIG. 2, the main measurement humidity sensor 6 is disposed on the surface of the first substrate 2 on the side of the electrophoretic material layer 4 and embedded in the sealing material 5. Further, as shown in FIG. 1, a plurality of auxiliary measurement humidity sensors 7 are provided along each side of the substrate at a position closer to the center of the substrate than the position of the main measurement humidity sensor 6 (in the display region 13). (In this embodiment, a total of 10 pieces, 4 pieces in the long side direction, and 3 pieces in the short side direction) are arranged at predetermined intervals. As shown in FIG. 2, the auxiliary measurement humidity sensor 7 is disposed on the surface opposite to the electrophoretic material layer 4 side of the second substrate 3 (surface opposite to the viewing side). Embedded in a sealing material 5 extending so as to go around to the surface opposite to the electrophoretic material layer 4 side. These main measurement humidity sensor 6 and auxiliary measurement humidity sensor 7 measure the humidity of the space between the first substrate 2 and the second substrate 3 (that is, the amount of water in the space).

  The electrophoretic display device of this embodiment controls the drive voltage applied to the electrophoretic material layer 4 according to the moisture content distribution in the space detected by the main measurement humidity sensor 6 and the auxiliary measurement humidity sensor 7. A control unit 15 (control means) is provided. As shown in FIG. 3, the control unit 15 includes an AD converter 16, a PLD (Programmable Logic Device) 17, a RAM 18, and a control circuit 19. Further, the control circuit 19 includes a display body drive control circuit 20, a CPU 21, a ROM 22, and a RAM 23. In addition, there are a display power supply circuit 24, a display drive circuit 25, an image rewriting button 26, and the like as a configuration related to driving of the electrophoretic display 1.

  The moisture amount data detected by the main measurement humidity sensor 6 and the auxiliary measurement humidity sensor 7 is analog-digital converted by the AD converter 16 and sent to the PLD 17. The PLD 17 is a LUT (Look Up) that shows the relationship between the moisture amount and the drive voltage based on the function of judging the moisture amount for each divided region from the moisture amounts obtained from the humidity sensors 6 and 7, and the obtained moisture amount. The drive voltage is determined with reference to the table (for example, stored in the ROM 22). The determined drive voltage is stored in the RAM 18. The “divided area” referred to here is one area obtained by dividing the entire display area 13, and the division method can be appropriately determined.

  For example, when the display area 13 shown in FIG. 1 is finely divided, if the long side direction of the display area 13 is finely divided into five equal parts or more, the main measurement humidity sensor 6 is included in the divided area. A divided area and a divided area not including the main measurement humidity sensor 6 can be formed. The amount of water in the divided area including the main measurement humidity sensor 6 can be represented by the amount of water detected by the main measurement humidity sensor 6. On the other hand, the water content in the divided areas not including the main measurement humidity sensor 6 can be calculated by interpolation from the water contents in the adjacent divided areas where the humidity sensors 6 and 7 are arranged.

  In this way, when the moisture content in all the divided regions is detected, the moisture content distribution in the entire display region can be determined. An example of the water content distribution when water enters the space is shown in FIG. This example is an example in the case where moisture has entered substantially uniformly from all directions due to deterioration of the sealing portion 5 or the like. In order from the periphery of the display region 13 toward the center, the region containing a lot of moisture (region A), the region containing a lot of moisture (region B), the region containing a little moisture (region C), and normal This is an area (area D). In this case, the amount of voltage correction with respect to the drive voltage in the normal region (region D) increases in order as region C <region B <region A.

Next, the flow until the PLD 17 determines the drive voltage based on the moisture amount detected by each of the humidity sensors 6 and 7 will be described with reference to FIG.
First, among the plural (12 in the present embodiment) main measurement humidity sensors 6, the amount of water detected by any one main measurement humidity sensor 6 is acquired (step S1 in FIG. 4). .

Here, the threshold values HTH1, HTH2, HTH3, and HTH4 of the moisture amount are set as follows.
When water content A1 <HTH1 <water content A2 <HTH2 <water content A3 <HTH3 <water content A4 <HTH4 <water content A5,
Moisture amount A1: An area where the amount of moisture is excessive and there is a problem in display quality without controlling the drive voltage.
Moisture amount A2: A region where the amount of moisture is large and can operate normally, but it is desirable to control the drive voltage.
Moisture amount A3: a region where it can operate normally,
Moisture amount A4: A region where the amount of moisture is small and it can operate normally, but it is desirable to have drive voltage control.
Water content A5: An area where the water content is too small and there is a problem in display quality without control of the drive voltage.

Then, the measured value Hi is compared with the threshold values HTH1 and HTH4 (step S2 in FIG. 4). When the measured value Hi is within the range of the threshold values HTH1 and HTH4, the measured value Hi is compared with the threshold values HTH2 and HTH3 (step S3 in FIG. 4).
If the measured value Hi is within the threshold values HTH2 and HTH3, it is determined that there is no abnormality (step S4 in FIG. 4).
In that case, a normal drive parameter (voltage) is set (step S5 in FIG. 4), and the electrophoretic display 1 is driven based on the drive parameter (step S6 in FIG. 4).

Returning to step S2, if the measured value Hi is outside the range of the threshold values HTH1 and HTH4, the surrounding humidity sensors 6 and 7 including the auxiliary measurement humidity sensor 7 are compared with the similar threshold values HTH1 and HTH4 (FIG. 4). Step S7).
For the surrounding humidity sensors 6 and 7, if the measured value Hi is outside the range of the threshold values HTH1 and HTH4, it is determined that a large amount of moisture has entered (step S8 in FIG. 4).

  At this time, it is determined whether or not the water content is sufficient to maintain the display quality by controlling the drive voltage (step S9 in FIG. 4). If the display quality is exceeded, the user needs repair. This is recommended (step S10 in FIG. 4). Whether or not the amount of water is sufficient to maintain display quality by controlling the driving voltage is determined by comparison with a threshold value stored in advance. Further, the recommendation to the user may be configured to notify the user, for example, by display when the PLD 17 issues a warning signal, or may be configured to notify by voice or the like. As a result, the user can take measures such as repairing at an early stage.

Returning to step S9, if the water content is sufficient to maintain the display quality, the electrophoretic display body is obtained from the water content information of the plurality of humidity sensors 6 and 7 (the water content itself, the elapsed time since the moisture intrusion was detected). The amount of water in each divided area in 1 is calculated (step S11 in FIG. 4). Thereby, the water content distribution in the display body is obtained.
Next, the drive voltage of each divided region is determined with reference to the LUT in which the moisture amount and the drive voltage are associated (step S12 in FIG. 4).

Returning to step S7, if the measured value Hi is within the threshold values HTH1 and HTH4 for the surrounding humidity sensors 6 and 7, it is determined that only the previous humidity sensor has failed, and the measured value is ignored ( Step S13 in FIG.
In that case, the process returns to step S5, and normal drive parameters (voltage) are set.

Returning to step S3, when the measured value Hi is within the threshold values HTH1 and HTH4 but outside the threshold values HTH2 and HTH3, the same threshold value is applied to the surrounding humidity sensors 6 and 7 including the auxiliary measurement humidity sensor 7. Comparison with HTH2 and HTH3 is performed (step S14 in FIG. 4).
As for the surrounding humidity sensors 6 and 7, if the measured value Hi is outside the range of the threshold values HTH2 and HTH3, it is determined that moisture has entered gently (step S15 in FIG. 4), The process proceeds to the step of calculating the amount of moisture (step S11) and the step of determining the drive voltage of each divided region (step S12).

Returning to step S14, when the measured value Hi is within the range of the threshold values HTH2 and HTH3 for the surrounding humidity sensors 6 and 7, the measured value Hi is constant for the previous humidity sensor in a state outside the range of the threshold values HTH2 and HTH3. It is checked whether or not time has passed (step S16 in FIG. 4).
If the measured value Hi is out of the threshold values HTH2 and HTH3 and a certain period of time has elapsed, it is determined that moisture has partially entered gently (step S17 in FIG. 4), and The process proceeds to the step of calculating the amount of moisture (step S11) and the step of determining the drive voltage of each divided region (step S12).

Returning to step S16, if the measured value Hi is out of the range of the threshold values HTH2 and HTH3 and the predetermined time has not elapsed, it is determined that the amount of the infiltrated water is very small.
In that case, the process returns to step S5, and normal drive parameters (voltage) are set.

  According to the electrophoretic display device of this embodiment, the moisture content distribution in the display body space is obtained from the moisture content information obtained from the plurality of humidity sensors 6 for main measurement and the humidity sensor 7 for auxiliary measurement, and the moisture content distribution is obtained. Based on this, the drive voltage applied to the electrophoretic material layer is controlled according to the position in the display region 13. Thereby, since the drive voltage of each place in the display area 13 can be appropriately controlled according to the state and degree of moisture permeation at that time, the display quality of the entire display area 13 can be sufficiently maintained. Further, since the main measurement humidity sensor 6 and the auxiliary measurement humidity sensor 7 are arranged in a double manner, it is possible to detect information such as the progress and spread of moisture intrusion. In this way, it is possible to know a more accurate and fine moisture distribution, and to appropriately control the drive voltage. Furthermore, a failure of the humidity sensor can be detected.

  Further, since the humidity sensor 6 for main measurement and the humidity sensor 7 for auxiliary measurement are embedded in the sealing material 5, it is possible to detect moisture intrusion very quickly and to fix the humidity sensors 6 and 7 separately. There is no need to prepare a fixed structure, and the structure is simple. Furthermore, since the auxiliary measurement humidity sensor 7 is provided on the surface of the first substrate 2 opposite to the viewing side, it does not hinder the visual recognition of the display, and the device structure is suitable for the present invention. Can do.

  In addition, since the driving voltage is controlled for each divided region, if a certain amount of moisture distribution is grasped by using a finite number of humidity sensors 6 and 7, the driving voltage can be sufficiently adjusted to maintain display quality. Is possible. At this time, in the divided areas where the humidity sensors 6 and 7 are not disposed, the moisture amount is estimated by interpolation from the moisture amount information in the neighboring divided areas where the humidity sensors 6 and 7 are disposed, and the moisture amount distribution is obtained. Therefore, it is possible to detect a fine water content distribution without increasing the number of humidity sensors. In addition, by obtaining the amount of moisture using the moisture amount information before and after the predetermined time detected by one humidity sensor 6, 7, a fine moisture content distribution can be obtained without increasing the number of humidity sensors. Can be detected.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the number and arrangement of humidity sensors are not limited to the above-described embodiment, and can be changed as appropriate, and other parts of the electrophoretic display device can be changed as appropriate.

It is a top view of the electrophoretic display device of one embodiment of the present invention. It is sectional drawing which follows the A-A 'line of FIG. It is a block diagram which shows the structure of the control part of the same electrophoretic display device. It is a flowchart for demonstrating operation | movement of the control part. It is a figure which shows an example of the moisture content distribution at the time of a water | moisture content permeating into the apparatus. It is a figure which shows a mode that the water | moisture content infiltrated in the conventional apparatus. It is a figure for demonstrating the display principle of a general electrophoretic display device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrophoretic display body, 2 ... 1st board | substrate, 3 ... 2nd board | substrate, 4 ... Electrophoretic material layer, 5 ... Sealing material, 6 ... Main measurement humidity sensor (1st humidity sensor), 7 ... Auxiliary measurement Humidity sensor (second humidity sensor), 13 ... display area, 15 ... control unit (control means).

Claims (11)

A first substrate provided with a plurality of pixel electrodes; a second substrate disposed opposite to the first substrate; an electrophoretic material layer sealed in a space between the first substrate and the second substrate; An electrophoretic display device comprising: a sealing material that seals the first substrate and the second substrate at a peripheral portion;
A plurality of humidity sensors for detecting the amount of moisture in the space;
The moisture content distribution in the space is obtained from the moisture content information detected by the plurality of humidity sensors, and the drive voltage applied to the electrophoretic material layer is controlled according to the position in the display region based on the moisture content distribution. And an electrophoretic display device.   The electrophoretic display device according to claim 1, wherein the plurality of humidity sensors are arranged at intervals in a direction along an outer periphery of the first substrate and the second substrate.   The plurality of humidity sensors include a plurality of first humidity sensors arranged at peripheral portions of the first substrate and the second substrate, and a central portion of the first substrate and the second substrate than the first humidity sensor. The electrophoretic display device according to claim 1, further comprising a plurality of second humidity sensors arranged close to each other.   The electrophoretic display device according to claim 3, wherein the plurality of first humidity sensors are provided inside the sealing material.   5. The electrophoretic display device according to claim 3, wherein the plurality of second humidity sensors are provided on a surface opposite to the viewing side of the first substrate.   The said control means controls the drive voltage in the said division area according to the said moisture content distribution for every division area which divided | segmented the display area. The electrophoretic display device described.   In the divided area where the humidity sensor is not arranged, the control means estimates the moisture amount by interpolating from the moisture amount information in the neighboring divided area where the humidity sensor is arranged, and obtains the moisture amount distribution. The electrophoretic display device according to claim 6.   The said control means calculates | requires the said moisture content distribution using the moisture content information before and behind predetermined time which the at least 1 humidity sensor detected among these several humidity sensors. The electrophoretic display device according to claim 1.   The control unit includes a storage unit that stores a lookup table in which a moisture amount in the space and an optimum driving voltage corresponding to the moisture amount are associated, and determines the driving voltage based on the lookup table. The electrophoretic display device according to claim 1, wherein the electrophoretic display device is an electrophoretic display device.   10. The control unit generates a warning signal when a moisture amount detected by at least one humidity sensor among the plurality of humidity sensors exceeds a maximum moisture amount that can be voltage controlled. The electrophoretic display device according to any one of the above. A first substrate provided with a plurality of pixel electrodes; a second substrate disposed opposite to the first substrate; an electrophoretic material layer sealed in a space between the first substrate and the second substrate; A method for driving an electrophoretic display device comprising: a sealing material that seals the first substrate and the second substrate at a peripheral edge portion;
A driving voltage applied to the electrophoretic material layer according to a position in a display area based on the moisture content distribution, by obtaining a moisture content distribution in the space from a plurality of moisture content information at each point in the space. A method for driving an electrophoretic display device, characterized in that control is performed.

Images