JP2011008174A - Optical recording display, driving method thereof, and electronic apparatus - Google Patents

Abstract

An optical writable display device capable of easily performing a reset operation with a relatively simple structure is provided.
An optical writing display device according to the present invention includes a display unit in which a plurality of pixels are arranged. The display unit includes a pixel electrode formed for each pixel, and a first electrode in the pixel electrode. A diode connected via the terminals, a common electrode opposed to the plurality of pixel electrodes, a plurality of electro-optic material layers having a memory property disposed between the pixel electrodes and the common electrode, A signal line connected to the second terminal of the diode and connected to each other directly or via an electric circuit is formed.
[Selection] Figure 1

Description

  The present invention relates to an optical writing display device, a driving method thereof, and an electronic apparatus.

  2. Description of the Related Art Conventionally, an optical writing type display device using a modulation medium having a memory property (cholesteric liquid crystal or electrophoretic dispersion liquid) is known. For example, in Patent Document 1 below, as an optical writing display device, a connection electrode is provided between a variable resistance layer whose resistance value is changed by light irradiation and a display medium layer for performing image display via a partial pressure control layer. It is disclosed to form a multilayer electrode structure in which a drive electrode and a release electrode are laminated.

JP 2007-171260 A

  According to the optical writable display device described in Patent Document 1, it is possible to erase (reset) the entire image displayed in the display area without irradiating light. On the other hand, however, the structure is complicated because a multi-layered electrode is formed for each pixel.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an optical writing display device and a driving method thereof that can easily perform a reset operation with a relatively simple structure. One of them.

  The optical writing type display device of the present invention includes a display unit in which a plurality of pixels are arranged. The display unit includes a pixel electrode formed for each pixel, and a first terminal connected to the pixel electrode. Connected to each other, a common electrode facing the plurality of pixel electrodes, a plurality of electro-optical material layers having a memory property disposed between the plurality of pixel electrodes and the common electrode, and a second of the diodes And a signal line connected to each other directly or via an electric circuit.

  According to this configuration, since a diode is used as the pixel switching element, a simple structure can be achieved. Then, by inputting an image signal for bringing the electro-optic material layer into a predetermined display state to the signal lines connected to each other, the entire display unit can be easily and quickly shifted to the same display state. Therefore, according to the present invention, it is possible to provide an optical writing display device that can easily perform a reset operation with a relatively simple structure.

It is also preferable to have a plurality of the display portions.
With such a configuration, images can be displayed in various forms. For example, it is possible to realize an optical writable display device capable of displaying a desired image using at least one display unit and performing handwriting input using at least one display unit.

A plurality of pixels belonging to the first display unit are arranged in the first region, and the first region is arranged in the first region. It is also preferable that a plurality of the pixels belonging to the second display unit different from the display unit are arranged.
With such a configuration, an area where handwriting input or the like is possible is formed in the other part (second display part) while using a part of the display part (first display part) as an image display area. can do.

The first display unit and the second display unit, wherein the pixel belonging to the first display unit and the pixel belonging to the second display unit are extending directions of the signal lines It is also preferable that they are arranged alternately along the line.
With such a configuration, a display unit in which pixels belonging to the first display unit and pixels belonging to the second display unit are mixed is used. Therefore, for example, a desired image is formed by the pixels belonging to the first display unit. And an overwriting function by handwriting input or the like can be realized by pixels belonging to the second display portion.

A control unit that controls the display unit, wherein the control unit inputs a first potential to the signal line; and a second operation inputs a second potential to the signal line; The second potential is lower than the potential of the common electrode when the first potential is higher than the potential of the common electrode, and the first potential is higher than the potential of the common electrode. When the potential is low, it is also preferable that the potential is higher than the potential of the common electrode.
Specifically, the display image on the display unit is erased by the first operation, and the display unit is held in a writable state by the second operation.
According to this configuration, the reset operation of the display unit can be easily performed by the first operation. In the second operation, the polarity of the potential difference with respect to the common electrode is opposite to that in the first operation. It is possible to make the display portion writable only by inputting a second potential.

The controller preferably performs a third operation of inputting a third potential that is substantially the same potential as the common electrode to the signal line after the first or second operation. Specifically, the display unit is held in a rewrite prohibited state by the third operation.
According to this configuration, after an image is displayed on the display unit in the second operation, it is possible to prevent unintended writing due to incident external light or the like, and it is possible to stably maintain the display state of the image. .

It is also preferable that the diode is a bidirectional diode, and the first potential is a potential equal to or higher than a threshold voltage of the diode, while the second potential is a potential lower than the threshold voltage of the diode. .
According to this configuration, it is possible to configure a photo-writing display device that can be easily reset using a bidirectional diode having both positive and negative threshold voltages.

The driving method of the optical writing type display device of the present invention includes a display unit in which a plurality of pixels are arranged. The display unit includes a pixel electrode formed for each pixel, and a first electrode in the pixel electrode. A diode connected via a terminal; a common electrode opposed to the plurality of pixel electrodes; an electro-optic material layer having a memory property disposed between the plurality of pixel electrodes and the common electrode; and the diode And a signal line connected to each other directly or via an electric circuit, wherein the signal line has a first potential. An image erasing step of inputting the signal, and when the first potential is higher than the potential of the common electrode, the first potential is lower than the potential of the common electrode. If it is lower than the potential An image writing step of inputting a second potential serial is higher than the potential of the common electrode, characterized by having a.
According to this driving method, the reset operation of the display unit can be easily executed in the image erasing step. Further, in the image writing step, the display portion can be image-written with a simple operation of inputting a second potential whose polarity difference with the common electrode potential is opposite to the first potential to the signal line. It can be.

It is preferable to include an image holding step of inputting a third potential that is substantially the same potential as the common electrode to the signal line.
According to this driving method, after an image is displayed on the display unit, it is possible to prevent unintended writing due to incident external light or the like, and it is possible to stably maintain the display state of the image.

The first display unit and the second display unit, and in the image writing step, the second potential is input to the signal line belonging to the second display unit, It is also preferable to input a third potential that is substantially the same potential as the common electrode to the signal line belonging to the first display portion.
According to this driving method, when the first and second display units are provided, the second display unit can be in a writable state while the first display unit can be in a write-inhibited state. . Thereby, the area | region which hold | maintains the displayed image and the area | region which enables handwritten input etc. can be formed.

An electronic apparatus according to the present invention includes the above-described optical writing display device.
According to this configuration, it is possible to provide an electronic apparatus including a display unit including an optical writing type display device that is excellent in functionality and manufacturability.

1 is a circuit configuration diagram of an electrophoretic display device according to a first embodiment. FIG. The top view of an electrophoretic display device, sectional drawing, sectional drawing of a microcapsule. The top view and sectional drawing of the element substrate in the specific example of a pixel circuit and 1 pixel. Operation | movement explanatory drawing of an electrophoretic element. The flowchart which shows the drive method which concerns on 1st Embodiment. The timing chart which shows the drive method which concerns on 1st Embodiment. FIG. 3 is a diagram illustrating two pixels that are targets for explanation of the driving method according to the first embodiment. FIG. 3 is a diagram illustrating two pixels that are targets for explanation in the driving method according to the first embodiment. Explanatory drawing of the image writing apparatus in the drive method which concerns on 1st Embodiment. The top view and operation explanatory drawing of the electrophoretic display apparatus which concern on a 1st modification. The figure which shows the pixel structure of the electrophoretic display device which concerns on a 3rd modification. The circuit block diagram of the electrophoretic display device which concerns on 2nd Embodiment. The top view and operation | movement explanatory drawing of the electrophoretic display device of 2nd Embodiment. The flowchart which shows the drive method which concerns on 2nd Embodiment. The circuit block diagram of the electrophoretic display device which concerns on 3rd Embodiment. The top view and operation | movement explanatory drawing of the electrophoretic display device of 3rd Embodiment. FIG. 14 illustrates an example of an electronic device. FIG. 14 illustrates an example of an electronic device.

The optical writing display device of the present invention will be described below with reference to the drawings.
The scope of the present invention is not limited to the following embodiment, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, the actual structure may be different from the scale, number, or the like in each structure.

(First embodiment)
FIG. 1 is a circuit configuration diagram of an electrophoretic display device which is a first embodiment of the optical writing type display device of the present invention.
The electrophoretic display device 100 includes a display unit 5 in which a plurality of pixels 40 are arranged in a matrix. The display unit 5 has m signal lines 66 (Y1, Y2,..., Yi,..., Ym), and n pixels 40 are connected to each signal line 66. Accordingly, the pixels 40 are arranged in a matrix of m rows × n columns.

  In the periphery of the display unit 5, connection wiring 66 a for connecting ends of the plurality of signal lines 66 extending from the display unit 5 and connection terminals 6 and 7 are formed. The connection terminal 6 is connected to all the signal lines 66 of the display unit 5 through the connection wiring 66a. The connection terminal 7 is connected to a common electrode 37 formed as an electrode common to the plurality of pixels 40.

  Each pixel 40 of the display unit 5 is provided with a diode 41, a pixel electrode 35, an electrophoretic element 32 (electro-optical material layer), and a common electrode 37. The anode terminal of the diode 41 is connected to the signal line 66, and the cathode terminal is connected to the pixel electrode 35.

Next, FIG. 2A is a plan view of the electrophoretic display device 100, and FIG. 2B is a partial cross-sectional view of the electrophoretic display device 100 in the display unit 5.
As shown in FIG. 2A, the display unit 5 is formed in a region where the element substrate 30 and the counter substrate 31 overlap in plan view, and in a region on the element substrate 30 protruding outside the counter substrate 31, A connection wiring 66 a connected to the signal line 66 extending from the display unit 5 is formed. The connection wiring 66 a is connected to the connection terminal 6 formed at one corner of the element substrate 30. The connection terminal 7 formed at a position adjacent to the connection terminal 6 is connected via a connection wiring 67 formed on the element substrate 30 and an inter-substrate connection portion 9 that electrically connects the element substrate 30 and the counter substrate 31. The common electrode 37 is connected.

As shown in FIG. 2B, the electrophoretic display device 100 is an electric device in which a plurality of microcapsules 20 are arranged between an element substrate (first substrate) 30 and a counter substrate (second substrate) 31. The electrophoretic element 32 is sandwiched.
In the display unit 5, a circuit layer 34 in which a signal line 66, a diode 41, and the like are formed is provided on the electrophoretic element 32 side of the element substrate 30, and a plurality of pixel electrodes 35 are arrayed on the circuit layer 34. Has been.
The element substrate 30 is a substrate made of glass, plastic, or the like and is not required to be transparent because it is disposed on the side opposite to the image display surface. The pixel electrode 35 has a voltage applied to an electrophoretic element 32 formed by laminating nickel plating and gold plating on a Cu (copper) foil in this order, Al (aluminum), ITO (indium tin oxide), or the like. Is an electrode to which is applied.

Here, the detailed structure of the pixel 40 will be described with reference to FIG.
FIG. 3A is a diagram illustrating a specific example of the pixel circuit. 3B is a plan view of the element substrate 30 in one pixel 40, and FIG. 3C is a cross-sectional view at a position along the line AA ′ in FIG. 3B.
As shown in FIG. 3A, the diode 41 employs a configuration in which transistors are diode-connected (configuration in which a source terminal and a gate terminal are short-circuited). In the case of the illustrated configuration, a plurality of signal lines 68 extending in a direction crossing the signal line 66 are formed, and the source terminals of the transistors constituting the diode 41 are connected to these signal lines 68. The signal lines 66 and 68 are connected at a position where the signal line 66 and the signal line 68 intersect.

  As shown in FIG. 3B, the diode 41 includes a semiconductor layer 41a having a substantially rectangular shape in plan view, a source electrode 41c extending from the signal line 68, and a drain connecting the semiconductor layer 41a and the pixel electrode 35. An electrode 41d and a gate electrode 41e extending from the signal line 66 are included. In the present embodiment, the source electrode 41 c and the gate electrode 41 e constitute the anode terminal of the diode 41, and the drain electrode 41 d constitutes the cathode terminal of the diode 41.

3C, the gate electrode 41e (signal line 66) made of Al or an Al alloy is formed on the element substrate 30, and the gate electrode 41e is covered with silicon oxide or silicon. A gate insulating film 41b made of nitride is formed. A semiconductor layer 41a made of amorphous silicon or polysilicon is formed in a region facing the gate electrode 41e via the gate insulating film 41b. A source electrode 41c and a drain electrode 41d made of Al or an Al alloy are formed so as to partially run over the semiconductor layer 41a. An interlayer insulating film 34a made of silicon oxide or silicon nitride is formed to cover the source electrode 41c (signal line 68), the drain electrode 41d, the semiconductor layer 41a, and the gate insulating film 41b. A pixel electrode 35 is formed on the interlayer insulating film 34a. The pixel electrode 35 and the drain electrode 41d are connected through a contact hole 34b that passes through the interlayer insulating film 34a and reaches the drain electrode 41d.
As shown in FIG. 3B, the signal line 66 and the signal line 68 are connected via a contact hole 34e formed at a position where they intersect. As a result, the source electrode 41c and the gate electrode 41e are electrically connected.

In the present embodiment, the signal lines 66 and the signal lines 68 are arranged so as to intersect with each other, and are wired in a grid pattern so as to surround each pixel 40. However, such a configuration is not necessarily required. The signal line 66 may be omitted and the source electrode 41c and the gate electrode 41e may be connected to the signal line 68, or the signal line 68 may be omitted and the gate line 41e and the source electrode 41c may be connected to the signal line 66. Good.
In the present embodiment, the signal line 66 and the signal line 68 are connected via the contact hole 34e. However, the contact hole 34e is omitted, and a wiring for connecting the gate electrode 41e and the signal line 68 is formed. Also good.

  As shown in FIG. 3B, a storage capacitor may be added to the pixel 40 by forming a capacitor line 36 in a region overlapping the pixel electrode 35 in plan view. For example, the capacitor line 36 can be formed in the same layer as the signal line 66 as a wiring extending along the signal line 66. By changing the area of the capacitor line 36 that overlaps the pixel electrode 35 in plan view, the size of the storage capacitor can be adjusted.

Returning to FIG. 2B, a planar common electrode 37 facing the pixel electrodes 35 is formed on the counter substrate 31 on the electrophoretic element 32 side, and the electrophoretic element 32 is formed on the common electrode 37. Is provided.
The counter substrate 31 is a substrate made of glass, plastic, or the like, and is a transparent substrate because it is disposed on the image display side. The common electrode 37 is an electrode for applying a voltage to the electrophoretic element 32 together with the pixel electrode 35, and is formed of MgAg (magnesium silver), ITO (indium tin oxide), IZO (indium zinc oxide) or the like. It is a transparent electrode.
The electrophoretic element 32 and the pixel electrode 35 are bonded via the adhesive layer 33, so that the element substrate 30 and the counter substrate 31 are bonded.

  In general, the electrophoretic element 32 is formed in advance on the counter substrate 31 side, and is handled as an electrophoretic sheet including the adhesive layer 33. In the manufacturing process, the electrophoretic sheet is handled in a state where a protective release sheet is attached to the surface of the adhesive layer 33. And the display part 5 is formed by sticking the said electrophoretic sheet which peeled off the release sheet with respect to the element substrate 30 (The pixel electrode 35, various circuits, etc.) which were manufactured separately. For this reason, the adhesive layer 33 exists only on the pixel electrode 35 side.

  FIG. 2C is a schematic cross-sectional view of the microcapsule 20. The microcapsule 20 has a particle size of, for example, about 50 μm and encloses therein a dispersion medium 21, a plurality of white particles (electrophoretic particles) 27, and a plurality of black particles (electrophoretic particles) 26. It is a spherical body. As shown in FIG. 2B, the microcapsule 20 is sandwiched between the common electrode 37 and the pixel electrode 35, and one or a plurality of microcapsules 20 are arranged in one pixel 40. One microcapsule 20 may be arranged over a plurality of pixels 40.

The outer shell portion (wall film) of the microcapsule 20 is formed using a translucent polymer resin such as an acrylic resin such as polymethyl methacrylate or polyethyl methacrylate, a urea resin, or gum arabic.
The dispersion medium 21 is a liquid that disperses the white particles 27 and the black particles 26 in the microcapsules 20. Examples of the dispersion medium 21 include water, alcohol solvents (methanol, ethanol, isopropanol, butanol, octanol, methyl cellosolve, etc.), esters (ethyl acetate, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). ), Aliphatic hydrocarbons (pentane, hexane, octane, etc.), alicyclic hydrocarbons (cyclohexane, methylcyclohexane, etc.), aromatic hydrocarbons (benzene, toluene, benzenes having a long-chain alkyl group ( Xylene, hexylbenzene, hebutylbenzene, octylbenzene, nonylbenzene, decylbenzene, undecylbenzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene)), halogenated hydrocarbons (methylene chloride, chloroform, tetrachloride) Element, and 1,2-dichloroethane), can be exemplified a carboxylate, it may be other oils. These substances can be used alone or as a mixture, and a surfactant or the like may be further blended.

The white particles 27 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 positively charged. The black particles 26 are particles (polymer or colloid) made of a black pigment such as aniline black or carbon black, and are used, for example, by being negatively charged.
These pigments include electrolytes, surfactants, metal soaps, resins, rubbers, oils, varnishes, compound charge control agents, titanium-based coupling agents, aluminum-based coupling agents, silanes as necessary. A dispersant such as a system coupling agent, a lubricant, a stabilizer, and the like can be added.
Further, instead of the black particles 26 and the white particles 27, for example, pigments such as red, green, and blue may be used. According to such a configuration, red, green, blue, or the like can be displayed on the display unit 5.

FIG. 4 is an operation explanatory diagram of the electrophoretic element. 4A shows a case where the pixel 40 displays white, and FIG. 4B shows a case where the pixel 40 displays black.
In the case of white display shown in FIG. 4A, the common electrode 37 is held at a relatively low potential, and the pixel electrode 35 is held at a relatively high potential. As a result, the positively charged white particles 27 are attracted to the common electrode 37, while the negatively charged black particles 26 are attracted to the pixel electrode 35. As a result, when this pixel is viewed from the common electrode 37 side which is the display surface side, white (W) is recognized.
In the case of black display shown in FIG. 4B, the common electrode 37 is held at a relatively high potential and the pixel electrode 35 is held at a relatively low potential. As a result, the negatively charged black particles 26 are attracted to the common electrode 37, while the positively charged white particles 27 are attracted to the pixel electrode 35. As a result, when this pixel is viewed from the common electrode 37 side, black (B) is recognized.
FIG. 4 is an explanatory diagram of the operation when the black particles are negative and the white particles are positively charged. However, if necessary, the black particles may be positively charged and the white particles negatively charged. Good. In this case, when a potential is supplied in the same manner as described above, a display in which white display and black display are reversed can be obtained.

[Driving method]
Next, a driving method of the electrophoretic display device of this embodiment will be described with reference to FIGS.
FIG. 5 is a flowchart showing a series of operations when an image is displayed on the electrophoretic display device 100. FIG. 6 is a timing chart corresponding to FIG. 7 and 8 are explanatory diagrams showing potential states of two pixels in each step of the driving method of the present embodiment. FIG. 9 is a diagram showing an image writing apparatus used for carrying out the driving method of the present embodiment.

FIG. 5 shows a flow when the pixel 40A shown in FIGS. 7 and 8 is displayed in black and 40B is displayed in white. In FIG. 6, the potential Vs of the signal line 66 (signal line 68) input via the connection terminal 6, the potential Vcom of the common electrode 37 input via the connection terminal 7, and the pixel electrode belonging to the pixel 40A. A potential Va of 35A and a potential Vb of the pixel electrode 35B belonging to the pixel 40B are shown.
7 and 8, the subscripts “A” and “B” in each symbol are used to clearly distinguish the two pixels 40 (40A and 40B) that are the objects of the description and the constituent elements belonging to them. There is no other intention.

  An image writing device 200 shown in FIG. 9 includes a light source device 210, a controller 220 (control unit), and an image mask 230. The controller 220 is provided with a plurality of connection terminals 221 respectively connected to the connection terminals 6 and 7 provided in the electrophoretic display device 100, and is configured to be able to supply a predetermined potential to the connection terminals 6 and 7. ing. In addition, the controller 220 drives and controls the light source device 210, irradiates the image mask 230 with the light LT emitted from the light source device 210, and uses the light LT that has passed through the opening 230 a of the image mask 230. The display unit 5 is irradiated.

  The image mask 230 may be one in which an opening 230a corresponding to an image is formed on a light-shielding substrate, and is an apparatus capable of electrically controlling transmission / blocking of light, such as a liquid crystal device. Also good. Furthermore, the pattern of the light LT formed by the image mask 230 may be reduced or enlarged to irradiate the electrophoretic display device 100.

As shown in FIG. 5, the driving method of the present embodiment includes an image erasing step S101 (first operation), an image writing step S102 (second operation), and an image holding step S103.
First, in the display unit 5 before the image erasing step S101, as shown in FIG. 7A, the pixel 40A is displayed in black and the pixel 40B is displayed in white. Since the connection terminals 6 to 8 are not connected to connection terminals of external devices, the pixel electrodes 35A and 35B and the common electrode 37 are all in a high impedance state (Hi-Z) in which they are electrically disconnected.

  Next, when executing the image erasing step S101 and the image writing step S102, the electrophoretic display device 100 is set in the image writing device 200 as shown in FIG. Specifically, the display unit 5 of the electrophoretic display device 100 and the image mask 230 are arranged so as to face each other, and the connection terminals 6 and 7 of the element substrate 30 correspond to the connection terminals 221 of the image writing device 200. Are connected to each other.

In the image erasing step S101, a high-level potential VH (for example, 10V: first potential) is applied to the signal line 66 (potential Vs) from the controller 220 of the image writing apparatus 200 via the connection terminals 6 and 7. Entered. In addition, the ground potential GND (0 V) is input to the common electrode 37 (potential Vcom).
In the image erasing step S101, the light source device 210 is in an off state, and the light LT is not irradiated to the electrophoretic display device 100.

  Then, as shown in FIG. 7B, the high level potential VH of the signal line 66 is input to the pixel electrodes 35A and 35B via the diodes 41A and 41B. Then, the electrophoretic element 32 is driven by the potential difference between the pixel electrodes 35A and 35B having the high level potential VH and the common electrode 37 having the ground potential GND, and both the pixels 40A and 40B are displayed in white (FIG. 4 ( a)). In the electrophoretic display device 100 of the present embodiment, all the signal lines 66 of the display unit 5 are connected to each other via the connection wiring 66a and are also connected to the signal line 68. All the pixels 40 of 5 are displayed in white, and the entire surface of the display unit 5 is erased.

  In the image erasing step S101, it is sufficient that all the pixels 40 of the display unit 5 can be shifted to a single gradation, and a specific driving method can be changed within a range in which such an object can be achieved. For example, in the above description, the potential Vcom of the common electrode 37 is the ground potential GND (0 V), but may be a low level potential VL (for example, −10 V).

Next, in the image writing step S102, a low level potential VL (for example, −10 V: second potential) is input from the controller 220 to the signal line 66 (potential Vs) via the connection terminals 6 and 7, The ground potential GND (0 V) is input to the common electrode 37 (potential Vcom).
In the state shown in FIG. 7C, the signal line 66 is at the low level potential VL, which is lower than the pixel electrodes 35A and 35B to which the high level potential VH is input in the image erasing step S101. 41B is in an off state. Accordingly, the display state of the display unit 5 does not change at this time.

If the electrophoretic display device 100 is held in the voltage application state, the light source device 210 is turned on by the controller 220, and the light LT emitted from the light source device 210 is transmitted through the image mask 230 to the electrophoretic display device. 100 is irradiated. In the example shown in FIG. 8A, the pixel 40A is irradiated with the light LT emitted from the image writing device 200, while the pixel 40B is not irradiated with the light LT. Then, a leak current is generated only in the diode 41A of the pixel 40A irradiated with light, and a current flows from the pixel electrode 35A to which the high level potential VH is input toward the signal line 66 in the image erasing step S101.
As a result, the potential Va of the pixel electrode 35A is lowered as shown in FIG. 6, and a potential difference is generated between the pixel electrode 35A and the common electrode 37 held at the ground potential GND. The electrophoretic element 32 is driven by the potential difference, and the pixel 40A shifts to black display (see FIG. 4B).
In this way, only the pixels 40 irradiated with the light LT among the pixels 40 of the display unit 5 are selectively shifted to black display, and a predetermined image is written on the display unit 5.

In the present embodiment, the potential Vcom of the common electrode 37 is held at the ground potential GND in the image writing step S102, but may be held at a high level potential VH (for example, 10 V). Even in this case, when the potential Va of the pixel electrode 35A belonging to the pixel 40A irradiated with light becomes lower than the potential Vcom of the common electrode 37, the pixel 40A changes to black display.
Further, the second potential is selected so as to have a polarity opposite to the first potential with respect to the potential Vcom of the common electrode 37. Alternatively, the second potential is lower than the potential Vcom when the first potential is higher than the potential Vcom of the common electrode 37, and is higher than the potential Vcom when the first potential is lower than the potential Vcom. .

Next, when proceeding to the image holding step S103, as shown in FIGS. 8B and 6, the signal line 66 (potential Vs) and the common electrode 37 (potential Vcom) are connected from the controller 220 via the connection terminals 6 and 7. ) Is inputted with the ground potential GND.
Thus, by making the signal line 66 and the common electrode 37 have the same potential, it is possible to prevent erroneous writing when the pixel 40 of the display unit 5 is irradiated with light. That is, in the image holding step S103, even if light is emitted to the pixel 40 and light leakage occurs in the diode 41, the potential of the pixel electrode 35 belonging to the pixel 40 irradiated with light becomes the ground potential GND. No potential difference occurs between the common electrode 37 held at the potential GND and the display state of the electrophoretic element 32 does not change.
After the image holding step S103, the electrophoretic display device 100 is detached from the image writing device 200, and the connection terminals 6 and 7 are disconnected from the connection terminal 221. Thereby, the signal line 66 and the common electrode 37 are brought into a high impedance state, and the image displayed on the display unit 5 is held.

  In the image holding step S103, the signal line 66 and the common electrode 37 do not necessarily have the same potential. Specifically, the potentials Vs and Vcom may be set so that the potential difference between the potential Vs of the signal line 66 and the potential Vcom of the common electrode 37 is equal to or lower than the threshold voltage of the electrophoretic element 32. Here, there is a case where there is no clear threshold voltage, but it may be set to a voltage that does not substantially affect the optical characteristics. Within such a range, even if the pixel 40 is irradiated with light and the potential Vs of the signal line 68 is input to the pixel electrode 35, the potential difference between the pixel electrode 35 and the common electrode 37 is the same as that of the electrophoretic element 32. The display voltage of the pixel 40 does not change because the voltage is lower than the threshold voltage.

  As described above in detail, the electrophoretic display device 100 of the present embodiment can use the same electrode structure as that of the active matrix liquid crystal device, so that the structure can be simplified and the productivity can be improved. It is excellent and advantageous in terms of cost. In addition, the entire display unit 5 can be shifted to a single gradation only by inputting a predetermined potential to the diode 41 via the signal line 66, and a reset operation can be executed easily and quickly.

[First Modification]
In the electrophoretic display device 100 of the above-described embodiment, the image writing is performed using the image writing device 200 including the image mask 230. However, handwriting input using an optical pen is performed on the electrophoretic display device 100. Can also be done.

FIG. 10A is a plan view of an electrophoretic display device 100A having a configuration suitable for handwriting input, and FIG. 10B is a schematic diagram illustrating a handwriting input operation.
The electrophoretic display device 100A shown in FIG. 10A is common to the electrophoretic display device 100 according to the first embodiment in its basic configuration, while the controller 63 is connected to the connection terminals 6 and 7 on the element substrate 30. The difference is that the (control unit) is implemented.

  In the electrophoretic display device 100A, the controller 63 executes each of the image erasing step S101, the image writing step S102, and the image holding step S103 shown in FIG. That is, the controller 63 controls the display unit 5 by inputting a predetermined potential to the signal line 66 (connection wiring 66a) and the common electrode 37 via the connection terminals 6 and 7 in steps S101 to S103.

More specifically, the controller 63 starts an image display operation on the display unit 5 in response to a signal input from a host device (not shown). When the image display operation is started, first, an image erasing step S101 is executed, the entire surface of the display unit 5 is displayed in white, and the previously displayed image is erased.
Thereafter, when the image writing step S102 is entered, the controller 63 inputs the low level potential VL to the signal line 66 and also inputs the ground potential GND to the common electrode 37, so that the display unit 5 can be written with the light pen 250. To a different state. When the display unit 5 held in a writable state is scanned with the light pen 250 that emits the light LT from the tip, only the pixels 40 irradiated with the light selectively shift to black display, An image corresponding to the locus of the pen 250 is displayed on the display unit 5.

  Thereafter, after a lapse of a predetermined time from the start of the image writing step S102, or the signal input from the host device, the process proceeds to the image holding step S103. Then, the controller 63 holds the signal line 66 and the common electrode 37 at substantially the same potential (ground potential GND). As a result, unintentional writing is prevented from being caused by external light incident on the display unit 5 or erroneous input of the optical pen 250.

  In the first modified example, the potential input to the common electrode 37 in the image erasing step S101 may be the low level potential VL. Further, the high level potential VH may be inputted to the common electrode 37 in the image writing step S102. In the image holding step S103, the signal line 66 and the common electrode 37 may have different potentials in a range where the potential difference between them is equal to or lower than the threshold voltage of the electrophoretic element 32.

Further, in the electrophoretic display device 100A, a mechanism for determining whether the light pen 250 is in contact with or close to the electrophoretic display device 100A may be provided. For example, a touch panel may be provided on the outer surface side of the counter substrate 31, or a piezoelectric sensor or an optical sensor may be provided on the counter substrate 31 or the element substrate 30.
By providing such a mechanism, when the light pen 250 is not in contact with or approaching the electrophoretic display device 100A, the ground potential GND (0 V) is input to the signal line 66, and the light pen 250 has contacted or approached. The signal line 66 can be driven to input the low level potential VL only at times. With such a driving method, writing can be performed with the optical pen 250 when necessary, and malfunction (unintentional writing) due to incidence of external light or the like can be prevented.

  Further, the electrophoretic display device 100A has a configuration suitable for handwritten input by the optical pen 250, but image writing by the image writing device 200 shown in FIG. 9 is also possible. In this case, the electrophoretic display device 100 </ b> A in which the display unit 5 can write an image by the controller 63 is set in the image writing device 200, and the display unit 5 is irradiated with light LT via the image mask 230. The image corresponding to the image mask 230 can be written in the electrophoretic display device 100A.

  Furthermore, although the electrophoretic display device 100A has been described as a configuration suitable for handwriting input using the optical pen 250, handwriting input using the optical pen is also performed in the electrophoretic display device 100 according to the first embodiment. Is possible. In this case, an external controller is connected to the connection terminals 6 and 7 of the electrophoretic display device 100, and the predetermined potential in the image writing step S102 is input from the external controller.

[Second Modification]
In the above-described embodiment, the image is erased by displaying the entire display unit 5 in white in the image erasing step S101, and the image is displayed by displaying some pixels 40 of the display unit 5 in black in the image writing step S102. However, it is also possible to display a white image component on a black background.
However, in this case, it is necessary to connect the diode 41 shown in FIG. 1 in the reverse direction (reverse connection to the pixel electrode 35) and to change the potential input to the signal line 66 in each step. .

In FIG. 1, a driving method for displaying a white image component on a black background on the assumption that the diode 41 is connected in the reverse direction will be described below.
First, in the image erasing step S101, a low level potential VL (for example, −10 V) is input to the signal line 66 (potential Vs) from the controller 220 of the image writing device 200 via the connection terminals 6 and 7, and the common electrode 37 is used. The ground potential GND (0 V) is input to (potential Vcom).
As a result, the pixel electrode 35 has a relatively low potential and the common electrode 37 has a relatively high potential, and the entire display unit 5 is displayed in black (see FIG. 4B). Note that a high level potential VH (for example, 10 V) may be input to the common electrode 37.

Next, in the image writing step S102, a high level potential VH (for example, 10V) is input from the controller 220 to the signal line 66 (potential Vs) via the connection terminals 6 and 7, and the common electrode 37 (potential Vcom) is input. The ground potential GND (0 V) is input.
When the light LT is irradiated to the pixel 40 held in the above-described potential state, a leak current is generated in the diode 41 irradiated with the light, and the potential of the pixel electrode 35 is increased. Accordingly, when the pixel electrode 35 has a relatively high potential and the common electrode 37 has a relatively low potential, the pixel 40 irradiated with this light shifts to white display. As a result, the display unit 5 is in a state where a white image component (a region irradiated with light) is displayed on a black background. In the image writing step S102, the low level potential VL may be input to the common electrode 37.

[Third Modification]
A third modification is an electrophoretic display device that includes a pixel 40M shown in FIG. 11 instead of the pixel 40 shown in FIG.
FIG. 11A is a plan view showing a pixel structure in a third modification, and FIG. 11B is a cross-sectional view of the element substrate at a position along the line BB ′ in FIG. 11A. .
A pixel 40M illustrated in FIG. 11 includes a bidirectional diode 41M made of an MIM (Metal-Insulator-Metal) element and a pixel electrode 35 connected to the bidirectional diode 41M. In the case of this example, the signal line 66 is made of a metal material such as Ta or Nb, for example, and covers the signal line 66 and oxidizes the composition metal of the signal line 66 (tantalum oxide or niobium oxide film). ) Or the like is formed. A pixel electrode 35 is formed in a region partially overlapping with the signal line 66 in plan view.
A portion 66b of the signal line 66 that overlaps the pixel electrode 35 in plan view constitutes one electrode of the MIM element, and an interlayer insulating film 34a on the portion 66b constitutes an insulating film of the MIM element. The portion on the insulating film 34a constitutes the other electrode of the MIM element.

The bidirectional diode 41M has threshold voltages on both the positive voltage side and the negative voltage side, and almost no current flows within the range of the positive and negative threshold voltages, while the positive and negative threshold voltages are reduced. When it exceeds, it has the property that the amount of current increases rapidly. Even if the applied voltage is within the threshold voltage, the amount of current increases when light is irradiated.
Therefore, the following driving method is adopted in the electrophoretic display device of the third modified example including the pixel 40M having the bidirectional diode 41M.

  First, also in the driving method according to the third modification, the image erasing step S101 (first operation), the image writing step S102 (second operation), and the image holding step S103 shown in FIG. 5 are performed. The point that the driving method including is applied is common to the first embodiment.

  Next, in the image erasing step S101, a positive voltage (for example, 10V) equal to or higher than the threshold voltage is input to the signal line 66. In addition, the ground potential GND (0 V) is input to the common electrode 37. Then, a positive voltage is input to the signal line 66 through the bidirectional diode 41M, and the pixel electrode 35 has a voltage obtained by subtracting the threshold voltage from the positive voltage. As a result, the electrophoretic element 32 is driven by the potential difference between the relatively high potential pixel electrode 35 and the relatively low potential common electrode 37, and all the pixels 40 </ b> M are displayed in white. The displayed image is erased.

  Next, in the image writing step S <b> 102, a negative voltage (for example, −5 V) less than the threshold voltage is input to the signal line 66, and the ground potential GND (0 V) is input to the common electrode 37. At this time, since the voltage of the signal line 66 is less than the threshold voltage, the bidirectional diode 41M is in the off state, and the display state of the display unit 5 does not change.

If the pixel 40M is held in the above-described voltage application state, the predetermined pixel 40M of the display unit 5 is irradiated with light. Then, in the pixel 40M irradiated with light, the leakage current of the bidirectional diode 41M increases, and the potential of the pixel electrode 35 decreases. As a result, the pixel electrode 35 has a relatively low potential and the common electrode 37 held at the ground potential GND has a relatively high potential, so that the pixel 40M irradiated with light shifts to black display.
In this way, only the pixels 40 irradiated with the light LT among the pixels 40 </ b> M of the display unit 5 are selectively shifted to black display, and a predetermined image is written on the display unit 5.

  Next, when proceeding to the image holding step S <b> 103, the ground potential GND is input to the signal line 66 and the common electrode 37. Thus, by making the signal line 66 and the common electrode 37 have the same potential, it is possible to prevent erroneous writing when the pixel 40M of the display unit 5 is irradiated with light.

  As described above in detail, according to the electrophoretic display device according to the third modified example, since the diode having a further simplified structure is employed, the structure is excellent in productivity and advantageous in terms of cost. . In the case of the third modified example, since the pixel 40M includes the bidirectional diode 41M, the potential input to the signal line 66 is changed only at each step, and on the black background, contrary to the above description. A white image can be displayed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 12 is a circuit configuration diagram of the electrophoretic display device according to the second embodiment, and FIG. 13 is an operation explanatory diagram of the electrophoretic display device according to the second embodiment.
In each drawing referred to below, the same reference numerals are given to the same components as those in the first embodiment and the modifications thereof, and detailed description thereof will be omitted.

As shown in FIG. 12, the electrophoretic display device 300 of the present embodiment includes a first display unit 5A and a second display unit 5B.
In the first display portion 5 </ b> A, m <b> 1 signal lines 66 are formed, and n <b> 1 pixels 40 are connected to the respective signal lines 66. Accordingly, the pixels 40 are arranged in a matrix of m1 rows × n1 columns. All the signal lines 66 formed in the first display portion 5A are connected to the connection terminal 6 through the connection wiring 66a. A common electrode 37 is connected to the connection terminal 7 provided side by side with the connection terminal 6.

  On the other hand, m2 signal lines 366 are formed in the second display portion 5B, and n2 pixels 340 are connected to each signal line 366. Accordingly, the pixels 340 are arranged in a matrix of m2 rows × n2 columns. All the signal lines 366 formed in the second display portion 5B are connected to the connection terminal 306 through the connection wiring 366a. The pixel 340 has the same configuration as the pixel 40 of the first display unit 5A, and includes a diode 41, a pixel electrode 35, an electrophoretic element 32, and a common electrode 37.

In the electrophoretic display device 300 of this embodiment, the number m1 of signal lines 66 and the number n1 of pixels 40 connected to the signal lines 66, the number m2 of signal lines 366, and the number of pixels 340 connected to the signal lines 366 are shown. The number n2 can be set to any natural number. That is, the first display unit 5A and the second display unit 5B can be configured by an arbitrary number of pixels 40 and 340, respectively.
Further, the definition of the pixels 40 and 340 may be different between the first display unit 5A and the second display unit 5B. For example, the first display unit 5A has fineness (for example, about 300 to 600 ppi) suitable for displaying characters and images, and the second display unit 5B has fineness (for example, about 50 to 100 ppi) suitable for handwriting input. Also good.
Furthermore, the outer shape of the first display unit 5A and the second display unit 5B is not limited to a rectangular shape, but may be an arbitrary planar shape such as a triangular shape, a pentagonal or higher polygonal shape, a circular shape, or an elliptical shape. Can do.

FIG. 13A is a plan view illustrating a schematic configuration of the electrophoretic display device 300.
The electrophoretic display device 300 includes an element substrate 330 and a counter substrate 31, and the first display unit 5A and the second display unit 5B are disposed in a region where the element substrate 330 and the counter substrate 31 overlap in plan view. Is formed. A controller 363 (control unit) is mounted on a region of the element substrate 330 that protrudes from the counter substrate 31. The controller 363 is connected to the connection terminals 6 and 7 and the connection terminal 306 shown in FIG.

  The element substrate 330 has the same configuration as the element substrate 30 except that the element substrate 330 includes a first display unit 5A and a second display unit 5B corresponding to the display unit 5 of the element substrate 30 according to the first embodiment. The controller 363 is configured to be able to supply a predetermined potential to the connection terminals 6 and 7 and the connection terminal 306.

[Driving method]
Next, a driving method of the electrophoretic display device 300 of this embodiment will be described.
FIG. 14 is a flowchart illustrating an example of a driving method of the electrophoretic display device of the present embodiment.
As shown in FIG. 14, the driving method according to the present embodiment includes a first image erasing step S201, a first image writing step S202, a first image holding step S203, and a second image erasing step S204. And a second image writing step S205 and a second image holding step S206.

In the first image erasing step S201 to the first image holding step S203, character information TXT as shown in FIG. 13A is written on the first display unit 5A, for example.
First, in the first image holding step S201, a high level potential VH (white display for the electrophoretic element 32 to be displayed in white on all signal lines 66 of the first display section 5A from the controller 363 via the connection terminal 6. For example, 10V) is input. In addition, the ground potential GND (0 V) is input to the common electrode 37 via the connection terminal 7. Thereby, the entire surface of the first display portion 5A is displayed in white and is in an erased state.

  Next, in the first image writing step S202, the electrophoretic display device 300 is set in the image writing device 200 shown in FIG. At this time, the image mask 230 on which the pattern corresponding to the character information TXT shown in FIG. 13 is formed and the first display unit 5A of the electrophoretic display device 300 are aligned and arranged. However, since the electrophoretic display device 300 includes the controller 363, the connection terminal 221 of the image writing device 200 is not connected to the electrophoretic display device 300.

  Thereafter, a low level potential VL (for example, −10 V) is input to the signal line 66 from the controller 363 via the connection terminals 6 and 7, and a ground potential GND (0 V) is input to the common electrode 37 (potential Vcom). As a result, the first display section 5A is in a state in which an image can be written.

  When the first display unit 5A is held in the voltage application state, the light source device 210 of the image writing device 200 is operated, and the light LT is transmitted to the first display unit 5A via the image mask 230. Irradiate. Thereby, a leak current is generated in the diode 41 in the pixel 40 irradiated with the light LT, and the potential of the pixel electrode 35 is lowered. As a result, the pixels 40 irradiated with light are selectively shifted to black display, and an image corresponding to the image mask 230 is displayed on the first display unit 5A.

  Thereafter, when the process proceeds to the first image holding step S203, the ground potential GND is input from the controller 363 to the signal line 66 and the common electrode 37 via the connection terminals 6 and 7. Thereby, the change in the display state of the first display unit 5A thereafter is prevented, and the display image is held.

If the character information TXT is displayed on the first display unit 5A as described above, the mode shifts to the handwriting input mode using the optical pen. In the handwriting input mode, the second image erasing step S204 to the second image holding step S206 are repeatedly executed once or a plurality of times.
In the handwriting input mode (steps S204 to S206), the first display unit 5A holds the potential state of the image holding step S203 described above, and the display image of the first display unit 5A does not change.

  In the second image erasing step S204, a high level potential VH (for example, 10 V) for displaying the electrophoretic element 32 in white on all signal lines 366 of the second display section 5B from the controller 363 via the connection terminal 306. ) Is entered. In addition, the ground potential GND (0 V) is input to the common electrode 37 via the connection terminal 7. As a result, the entire surface of the second display portion 5B is displayed in white and is in an erased state.

Next, in the second image writing step S205, as shown in FIG. 13B, handwritten input with the optical pen 250 is performed on the second display unit 5B of the electrophoretic display device 300.
In the second image writing step S205, a low level potential VL (eg, −10 V) is input to the signal line 366 from the controller 363 via the connection terminal 306. In addition, the ground potential GND (0 V) is input to the common electrode 37 (potential Vcom) via the connection terminal 7. As a result, the second display section 5B is in a state in which an image can be written.

  Then, when the optical pen 250 is brought close to the second display unit 5B held in the voltage application state as shown in FIG. 13B, the pixel 340 irradiated with the light LT of the optical pen 250. In FIG. 5, a leak current is generated in the diode 41, and the potential of the pixel electrode 35 is lowered. As a result, the pixel 340 irradiated with light is selectively shifted to black display, and a black mark is written on the second display portion 5B.

  Thereafter, when the process proceeds to the second image holding step S206, the ground potential GND is input from the controller 363 to the signal line 366 via the connection terminal 306, and the ground potential GND is input to the common electrode 37 via the connection terminal 7. . Thereby, also in the 2nd display part 5B, the change of a display state is prevented and the written black mark is hold | maintained.

  As described above in detail, according to the electrophoretic display device 300 of the second embodiment, the first display unit 5A and the second display unit 5B can be operated independently of each other. That is, only the second display unit 5B can be in a state where image writing is possible while fixing the display state of the first display unit 5A. Thereby, for example, horizontally written character information is displayed on the first display unit 5A, and then a check symbol or the like is added to the beginning of the line (second display unit 5B) with the optical pen 250 or the like. It can be used suitably.

  In the electrophoretic display device 300 of the present embodiment, a mechanism for determining whether the optical pen 250 is in contact with or close to the electrophoretic display device 300 may be provided. Thereby, writing can be performed with the optical pen 250 when necessary, and malfunction (unintentional writing) due to incidence of external light or the like can be prevented.

  The second display unit 5B may be provided not only at the beginning (left side in the figure) of the character information TXT displayed on the first display unit 5A but also at the end of the line (right side in the figure). Furthermore, you may provide in the one side part (upper side part) of the column direction (direction orthogonal to a row direction) of the character information TXT in the 1st display part 5A, and the other side part (lower side part).

In the above embodiment, the case has been described in which the character information TXT is displayed only on the first display unit 5A and the display state is fixed at the time of handwriting input. However, the character information and image are also displayed on the second display unit 5B. Of course, you can make it happen.
When both the first display unit 5A and the second display unit 5B are used for image display, the first display is performed in the first image erasing step S201 to the first image holding step S203 shown in FIG. By simultaneously driving the unit 5A and the second display unit 5B, an image can be easily written.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS.
FIG. 15 is a circuit configuration diagram of the electrophoretic display device according to the third embodiment, and FIG. 16 is an operation explanatory diagram of the electrophoretic display device according to the third embodiment.
In each drawing referred to below, the same reference numerals are given to the same components as those in the first embodiment, the modified example, and the second embodiment, and the detailed description thereof will be omitted.

As shown in FIG. 15, the electrophoretic display device 400 of this embodiment includes a display unit 50 in which a plurality of pixels 40 and a plurality of pixels 340 are arranged.
The display unit 50 is provided with a plurality of signal lines 66 and a plurality of pixels 40 connected to each signal line 66. All the signal lines 66 are connected to the connection terminal 6 through the connection wiring 66a. In addition, a plurality of signal lines 366 and a plurality of pixels 340 connected to each signal line 366 are formed. All the signal lines 366 are connected to the connection terminal 306 through the connection wiring 366a.
Each of the pixels 40 and 340 includes a diode 41, a pixel electrode 35, an electrophoretic element 32, and a common electrode 37.

  In the case of this embodiment, in the display unit 50, the pixels 40 and 340 are mutually connected in the row direction (extending direction of the signal lines 66 and 366) and the column direction (extending direction of the connection wirings 66a and 366a). They are arranged alternately so as to be adjacent to each other. That is, the electrophoretic display device 400 of the present embodiment has a configuration in which the pixels 40 of the first display unit 5A according to the second embodiment and the pixels 340 of the second display unit 5B are mixedly arranged in a checkered pattern. I have.

FIG. 16A is a plan view showing a schematic configuration of the electrophoretic display device 400.
The electrophoretic display device 400 includes an element substrate 430 and a counter substrate 31, and the display unit 50 is formed in a region where the element substrate 430 and the counter substrate 31 overlap in plan view. A controller 363 (control unit) is mounted in a region of the element substrate 430 that protrudes beyond the counter substrate 31. The controller 363 is connected to the connection terminals 6 and 7 and the connection terminal 306 shown in FIG.

  The element substrate 430 has the same configuration as the element substrate 330 according to the second embodiment except for the arrangement of the pixels 40 and the pixels 340. The controller 363 is configured to be able to supply a predetermined potential to the connection terminals 6 and 7 and the connection terminal 306, and controls a plurality of pixels 40 belonging to the display unit 50 by potential input via the connection terminals 6 and 7. The plurality of pixels 340 can be controlled by potential input via the connection terminals 7 and 306.

[Driving method]
Next, a driving method of the electrophoretic display device 400 of the present embodiment will be described.
The flowchart shown in FIG. 14 can be applied to the driving method of the electrophoretic display device 400 of the present embodiment. That is, the first image erasing step S201, the first image writing step S202, the first image holding step S203, the second image erasing step S204, the second image writing step S205, A driving method including the second image holding step S206 can be applied.

In the first image erasing step S201 to the first image holding step S203 in the present embodiment, a desired image is written in the array of the pixels 40 of the display unit 50.
Specifically, in the first image holding step S201, a high-level potential VH (for example, for displaying the electrophoretic element 32 in white on all the signal lines 66 of the display unit 50 from the controller 363 via the connection terminal 6 is used. 10V) is input. In addition, the ground potential GND (0 V) is input to the common electrode 37 via the connection terminal 7. As a result, all the pixels 40 of the display unit 50 are displayed in white and are in an erased state.

  Next, in the first image writing step S202, the electrophoretic display device 400 is set in the image writing device 200 shown in FIG. At this time, the image mask 230 on which a pattern corresponding to the image to be displayed on the display unit 50 is formed and the display unit 50 of the electrophoretic display device 300 are aligned and arranged. However, since the electrophoretic display device 400 includes the controller 363, the connection terminal 221 of the image writing device 200 is not connected to the electrophoretic display device 400.

  Thereafter, a low level potential VL (for example, −10 V) is input to the signal line 66 from the controller 363 via the connection terminals 6 and 7, and a ground potential GND (0 V) is input to the common electrode 37 (potential Vcom). Thereby, the pixel 40 of the display unit 50 is in a state in which an image can be written.

  If the pixel 40 is maintained in the voltage application state, the light source device 210 of the image writing device 200 is operated to irradiate the display unit 50 with the light LT via the image mask 230. Thereby, a leak current is generated in the diode 41 in the pixel 40 irradiated with the light LT, and the potential of the pixel electrode 35 is lowered. As a result, the pixels 40 irradiated with light are selectively shifted to black display, and an image corresponding to the image mask 230 is displayed on the display unit 50.

  Thereafter, when the process proceeds to the first image holding step S203, the ground potential GND is input from the controller 363 to the signal line 66 and the common electrode 37 via the connection terminals 6 and 7. Thereby, the change of the display state of the pixel 40 after that is prevented, and the display image is held.

If the image comprised by the pixel 40 is displayed by the above, it will transfer to the handwriting input mode by an optical pen. In the handwriting input mode, the second image erasing step S204 to the second image holding step S206 are repeatedly executed once or a plurality of times.
In the handwriting input mode (steps S204 to S206), the pixel 40 holds the potential state of the image holding step S203 described above, and the already displayed image does not change.

  In the second image erasing step S204, a high level potential VH (for example, 10V) for displaying the electrophoretic element 32 in white is input to all the signal lines 366 of the display unit 50 from the controller 363 via the connection terminal 306. Is done. In addition, the ground potential GND (0 V) is input to the common electrode 37 via the connection terminal 7. As a result, all the pixels 340 of the display unit 50 are displayed in white and are in an erased state.

Next, in the second image writing step S205, as shown in FIG. 16B, handwriting input by the optical pen 250 is performed in the area composed of the pixels 340 in the display unit 50 of the electrophoretic display device 400. .
In the second image writing step S205, a low level potential VL (eg, −10 V) is input to the signal line 366 from the controller 363 via the connection terminal 306. In addition, the ground potential GND (0 V) is input to the common electrode 37 (potential Vcom) via the connection terminal 7. Thereby, the pixel 340 is in a state in which an image can be written.

  When the pixel 340 is scanned with the light pen 250 as shown in FIG. 16B on the display unit 50 in which the voltage application state is maintained, the diode 41 in the pixel 340 irradiated with the light LT of the light pen 250. A leak current is generated in the pixel electrode 35, and the potential of the pixel electrode 35 decreases. As a result, the pixel 340 irradiated with light is selectively shifted to black display, and the image can be overwritten as shown in the figure.

  Thereafter, when the process proceeds to the second image holding step S206, the ground potential GND is input from the controller 363 to the signal line 366 via the connection terminal 306, and the ground potential GND is input to the common electrode 37 via the connection terminal 7. . As a result, the display state of the image composed of the pixels 340 is also prevented from being changed, and the entered image is retained.

  As described above in detail, according to the electrophoretic display device 400 of the third embodiment, the pixels 40 and the pixels 340 are mixedly arranged in a checkered pattern. Can be displayed and handwritten input using the pixels 340 can be performed. Thereby, for example, character information or the like is displayed by the pixel 40, and it can be suitably used for an application in which a check symbol, a line segment, or the like is added with the optical pen 250 or the like.

  In the electrophoretic display device 400 of this embodiment, a mechanism for determining whether the optical pen 250 is in contact with or close to the electrophoretic display device 400 may be provided. Thereby, writing can be performed with the optical pen 250 when necessary, and malfunction (unintentional writing) due to incidence of external light or the like can be prevented.

  In the above embodiment, an image is displayed using only the pixel 40, and an image by handwriting input is displayed by the pixel 340. However, character information and an image may be displayed by both the pixel 40 and the pixel 340. Good. In this case, an image can be easily written by simultaneously driving the pixel 40 and the pixel 340 in the first image erasing step S201 to the first image holding step S203 shown in FIG. In this case, the process may move to the second image writing step S205 without executing the second image erasing step S204. In this way, in the second image writing step S205, among the pixels 340, the pixels 340 that are not used for image display in the first image erasing step S201 to the first image holding step S203 (that is, black Handwritten input can be performed on the pixel 340) that is not displayed. That is, the image written by handwriting in the second image writing step S205 is overwritten on the image written in the pixel 40 and the pixel 340 through the first image erasing step S201 to the first image holding step S203. Can do.

  Further, in the electrophoretic display device 400 of the present embodiment, the display unit 50 can be configured by an arbitrary number of pixels 40 and 340, respectively. Further, in the present embodiment, the pixels 40 and the pixels 340 are arranged in a one-to-one correspondence, but the number ratio may be different. For example, a configuration in which a number of pixels 340 about ½ to 1/10 of the number of pixels 40 is mixed in an area where a large number of pixels 40 are arranged. Further, the dimensions of the pixel 40 and the pixel 340 may be different. For example, the pixel 40 is formed to have a dimension suitable for displaying characters and images (for example, about 300 to 600 ppi), and the pixel 340 has a dimension suitable for handwriting input (for example, about 50 to 100 ppi). It may be formed.

The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.
For example, in each of the above embodiments, the light LT is irradiated from the outer surface side of the counter substrate 31, but the light LT may be irradiated from the outer surface side of the element substrate 30 or the element substrate 330. In some cases, the light LT may be irradiated from both the outer surface side of the counter substrate 31 and the outer surface side of the element substrate 30 (330).

The configuration of the diode 41 is not particularly limited, and may be a PIN diode using amorphous silicon or polysilicon in addition to a configuration in which transistors using amorphous silicon or polysilicon are diode-connected. Further, a transistor in which an organic semiconductor layer is used may be diode-connected.
If the structure uses amorphous silicon or polysilicon, the sensitivity to the light LT is good, and the energy for optical writing can be reduced. In addition, it is easy to enlarge the screen. On the other hand, a transistor using an organic semiconductor layer can be formed at a low temperature and can be formed on a transparent member that is more flexible than glass.

Furthermore, the configuration of the pixels 40 and 340 is not particularly limited, and various configurations can be employed. For example, the pixels 40 and 340 may be provided with a storage capacitor connected in parallel to the electrophoretic element 32.
Further, although cases have been described with the above embodiments where the signal lines 66 and the signal lines 366 are connected to each other via the connection wirings 66a and 366a, the present invention is not limited to such a configuration. For example, the signal lines 66 (366) may be connected to each other via another electric circuit. In other words, a configuration may be adopted in which a drive circuit is provided that is connected to the signal line 66 (366) and has a function of collectively selecting all the signal lines 66 (366).

  In each of the above embodiments, the electrophoretic display device including the electrophoretic element 32 as the electro-optical material layer has been described as an example. However, the electro-optical material layer is not limited to the electrophoretic element and has a memory property. If so, a known electro-optic material layer can be applied. For example, an electro-optical material layer composed of cholesteric liquid crystal, PDLC, electrochromic material, twisting ball, toner, or the like can be used.

(Electronics)
Next, a case where the electrophoretic display devices 100, 100A, 300, and 400 of the above embodiments are applied to an electronic device will be described.
FIG. 17 is a perspective view illustrating a configuration of the electronic paper 1100. The electronic paper 1100 includes the electrophoretic display device 100 (100A, 300, 400) of the above-described embodiment in a display area 1101. The electronic paper 1100 is flexible and includes a main body 1102 made of a rewritable sheet having the same texture and flexibility as conventional paper.

  FIG. 18 is a perspective view showing the configuration of the electronic notebook 1200. An electronic notebook 1200 is obtained by bundling a plurality of the electronic papers 1100 and sandwiching them between covers 1201. The cover 1201 includes display data input means (not shown) for inputting display data sent from an external device, for example. Thereby, according to the display data, the display content can be changed or updated while the electronic paper is bundled.

According to the electronic paper 1100 and the electronic notebook 1200 described above, since the electrophoretic display device according to the present invention is employed, the optical writing type display unit configured to be easily reset by a simple structure is provided. Electronic equipment.
In addition, said electronic device illustrates the electronic device which concerns on this invention, Comprising: The technical scope of this invention is not limited. For example, the electrophoretic display device (optical writing display device) according to the present invention can also be suitably used for a display portion of an electronic device such as a mobile phone or a portable audio device.

  100, 100A, 300, 400 Electrophoretic display device (optical writing display device), 5, 50 display unit, 5A first display unit, 5B second display unit, 6, 7, 306 connection terminal, 9 between substrates Connection part, 30, 330, 430 Element substrate, 31 Counter substrate, 32 Electrophoretic element (electro-optic material layer), 33 Adhesive layer, 35 pixel electrode, 37 Common electrode, 40, 40A, 40B, 40M, 340 pixel, 41, 41A, 41B, 41M Diode, 63, 363 Controller (control unit), 66, 68, 366 Signal line, 66a, 366a, 67 Connection wiring, LT light

Claims (13)

A display unit in which a plurality of pixels are arranged;
In the display section,
A pixel electrode formed for each pixel, and a diode connected to the pixel electrode via a first terminal;
A common electrode facing the plurality of pixel electrodes;
An electro-optic material layer having memory properties disposed between the plurality of pixel electrodes and the common electrode;
A signal line connected to the second terminal of the diode and connected to each other directly or via an electric circuit;
An optical writable display device characterized in that is formed.   The optical writing display device according to claim 1, comprising a plurality of the display units. A first region and a second region partitioned in a plane;
The plurality of pixels belonging to the first display unit are arranged in the first region, while the plurality of pixels belonging to the second display unit different from the first display unit are arranged in the second region. 3. The optical writing display device according to claim 2, wherein pixels are arranged. The first display unit and the second display unit,
The pixel belonging to the first display portion and the pixel belonging to the second display portion are alternately arranged along the extending direction of the signal line. The optical writing type display device described. A control unit for controlling the display unit;
The control unit inputs a first potential to the signal line;
A second operation of inputting a second potential to the signal line;
Run
The second potential is lower than the potential of the common electrode when the first potential is higher than the potential of the common electrode, and when the first potential is lower than the potential of the common electrode. The optical writing display device according to claim 1, wherein the potential is higher than the potential of the common electrode.   The light according to claim 5, wherein the control unit erases a display image of the display unit by the first operation and holds the display unit in a writable state by the second operation. Writable display device.   The control unit performs a third operation of inputting a third potential that is substantially the same potential as the common electrode to the signal line after the first or second operation. 5. The optical writing display device according to 5 or 6.   The optical writing display device according to claim 7, wherein the control unit holds the display unit in a rewrite-inhibited state by the third operation. The diode is a bidirectional diode;
9. The device according to claim 1, wherein the first potential is a potential equal to or higher than a threshold voltage of the diode, and the second potential is a potential lower than the threshold voltage of the diode. The optical writing type display device according to claim 1. A display unit in which a plurality of pixels are arranged; a pixel electrode formed for each pixel in the display unit; a diode connected to the pixel electrode through a first terminal; A common electrode facing the pixel electrode, an electro-optic material layer having a memory property disposed between the plurality of pixel electrodes and the common electrode, and a second terminal of the diode and connected directly to each other Or a signal line connected via an electric circuit, and a method for driving an optical writing type display device comprising:
An image erasing step of inputting a first potential to the signal line;
When the first potential is higher than the potential of the common electrode, the signal line has a potential lower than the potential of the common electrode, and when the first potential is lower than the potential of the common electrode, And an image writing step of inputting a second potential which is higher than the potential of the electrode.   The method of driving an optical writing display device according to claim 10, further comprising an image holding step of inputting a third potential that is substantially the same potential as the common electrode to the signal line. The first display unit and the second display unit;
In the image writing step,
While inputting the second potential to the signal line belonging to the second display unit,
12. The optical writing display device according to claim 10, wherein a third potential that is substantially the same potential as that of the common electrode is input to the signal line belonging to the first display portion. Method.   An electronic apparatus comprising the optical writing display device according to claim 1.

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