JP4036045B2 - Display device and driving method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal deposition type display device that performs display by metal deposition / dissolution and a driving method thereof, and more particularly to a display device suitable for so-called electronic paper and a driving method thereof.
[0002]
[Prior art]
In recent years, with the spread of networks, documents that have been distributed in the form of printed materials have been distributed in the form of so-called electronic documents. Furthermore, books and magazines are often provided in the form of so-called electronic publishing. In order to view such information, reading from a CRT (cathode ray tube) or liquid crystal display of a computer has been widely performed.
[0003]
However, it has been pointed out that a light-emitting display such as the CRT is extremely fatigued for ergonomic reasons and cannot withstand long-time reading. In addition, even a light-receiving display such as a liquid crystal display is not suitable for reading because of the flicker specific to fluorescent tubes used for backlights. In addition, there is a problem that the reading place is limited to the place where the computer is installed.
[0004]
In recent years, a reflective liquid crystal display that does not use a backlight has been put into practical use. However, the reflectance when no liquid crystal is displayed (white display) is 30 to 40%, which is the reflectance of printed matter on paper (OA paper). And the reflectance of 75% for paperback books and 52% for newspapers). In addition, fatigue is likely to occur due to glare caused by the reflector, and this is also not able to withstand long-time reading.
[0005]
In order to solve these problems, what is called a paper-like display or electronic paper is being developed. Specifically, an electrophoretic display that moves colored particles between electrodes by electrophoresis, a two-color ball display that colors dichroic particles by rotating them in an electric field, electrochemical oxidation / reduction Electrochromic display that develops color based on the action, metal deposition type electrochemical display device (Electrodeposition) that displays by utilizing the color change caused by the deposition and dissolution of metal by electrochemical oxidation and reduction. Display). Each of these displays is a non-luminous display that does not emit light by itself, has a memory effect that remains displayed even when the power is turned off, and is expected as a display for displaying characters.
[0006]
[Problems to be solved by the invention]
By the way, for example, a metal deposition type (electrodeposition type) electrochemical display device that performs display by precipitation / dissolution of the metal is an electronic display element having the same quality as that printed on paper, and this is displayed by hand. If it can be applied to a device, its use is expected to greatly expand. If a handwritten display device can be realized with the metal deposition type display device, paper culture can be digitized, which not only adds convenience, but also contributes as an effective tool in business or education. That would be easily guessed.
[0007]
However, since the metal deposition type electrochemical display device requires a certain amount of time for the deposition and dissolution of the metal, there remains a big problem that the display speed cannot follow the handwritten speed. For example, in a liquid crystal panel or the like, position information from a touch panel or a tablet is once stored in a memory, and a screen is scanned based on the information from the memory to display input information. In the liquid crystal panel, since the response speed is fast, there is no problem even with the above-described method. In a metal deposition type display device, if this method is applied as it is, the display cannot catch up and handwritten information is displayed with a delay, and the advantage of handwriting input is greatly impaired.
[0008]
The present invention has been proposed in view of such conventional situations. That is, the present invention aims at realizing a handwritten display device at a practical level in a display device called so-called electronic paper, and provides a display device driving method that enables display capable of following the handwriting speed. With the goal.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a display device of the present invention detects a coordinate position on a screen in a display device in which pixels are selectively colored by energization and the coloring state is maintained even after the energization is interrupted. It has position information detection means, and direct drawing is performed based on the position information from the position information detection means. After the direct drawing, additional writing is performed by applying a uniform voltage across the entire surface. It is characterized by that. The display device driving method of the present invention is a display device driving method in which pixels are selectively colored by energization and the coloring state is maintained even after the energization is cut off. Draw directly based on After the direct drawing, additional writing is performed by applying a uniform voltage across the entire surface. It is characterized by this.
[0010]
Since a liquid crystal panel or the like does not have a memory property for display, in order to display a handwritten input screen, the position information drawn by the pen is once taken into the image memory, the screen information of the display device is rewritten, and then based on this. And rewrite the entire screen by XY scanning. In this method, the entire screen is rewritten for each point drawn by the pen, and when applied as it is to a metal deposition type display device having a slow response speed, it is difficult to draw the screen following the pen.
[0011]
Therefore, in the present invention, for example, a voltage is applied directly to the X and Y electrode terminals of the display device from the position information (X, Y) at each time point when the handwriting pen is generated. Thereby, writing corresponding to the position of the pen is performed in a short time. Due to its characteristics, the metal deposition type display device has a memory effect to hold an image, and an already written image remains as it is even after voltage application is stopped. Thus, the position information can be directly written.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a display device to which the present invention is applied and a driving method thereof will be described in detail with reference to the drawings.
[0013]
The display device of this example is a metal deposition type electrochemical display device (so-called electrodeposition type display device) in which display is performed by deposition and dissolution of metal using the electrodeposition characteristics. For example, a simple matrix driving method is used. It is driven by. In the case of the simple matrix driving method, the driving electrode is the first electrode group X. ₁ , X ₂ ... and second electrode group Y orthogonal to this ₁ , Y ₂ These are arranged in a lattice pattern so as to cross each other. FIG. 1 and FIG. 2 show the specific structure, and a striped transparent column electrode 2 corresponding to the first electrode group is formed on the transparent substrate 1. Further, a base substrate 3 on which a stripe-like counter electrode (row electrode) 4 corresponding to the second electrode group is formed is disposed so as to face this, and these are superposed via a polymer electrolyte layer 5. A predetermined number of the transparent column electrodes 2 and row electrodes 4 are formed according to the number of pixels, and the intersection of these is a pixel.
[0014]
In the display device of this example, a striped transparent column electrode 2 corresponding to the first electrode group is formed on the transparent substrate 1. Further, a base substrate 3 on which a stripe-like counter electrode (row electrode) 4 corresponding to the second electrode group is formed is disposed so as to face this, and these are superposed via a polymer electrolyte layer 5. A predetermined number of the transparent column electrodes 2 and row electrodes 4 are formed according to the number of pixels, and the intersection of these is a pixel. Then, by selectively applying a voltage between the transparent column electrode 2 and the row electrode 4, the metal 6 is deposited, and the pixels are colored.
[0015]
In the above configuration, the transparent substrate 1 can be a transparent glass substrate such as a quartz glass plate or a white plate glass plate, but is not limited thereto, an ester such as polyethylene naphthalate or polyethylene terephthalate, polyamide, Polycarbonate such as polycarbonate, cellulose ester such as cellulose acetate, fluoropolymer such as polyvinylidene fluoride and tetrafluoroethylene-hexafluoropropylene copolymer, polyether such as polyoxymethylene, polyacetal, polystyrene, polyethylene, polypropylene, methylpentene polymer And polyimides such as polyimide-amide and polyetherimide can be mentioned as examples. When these synthetic resins are used as a support, a rigid substrate that does not easily bend can be used, but a flexible film-like substrate can also be used.
[0016]
For the transparent column electrode 2, for example, In ₂ O _Three And SnO ₂ A mixture of so-called ITO film and SnO ₂ Or In ₂ O _Three It is preferable to use a film coated with. These ITO films and SnO ₂ Or In ₂ O _Three The film coated with Sn may be doped with Sn or Sb, and MgO, ZnO, or the like may be used.
[0017]
On the other hand, as the polymer for the matrix (matrix) used for the polymer electrolyte layer 5, the skeleton unit is-(C-C-O), respectively. _n -,-(C-C-N) _n -,-(C-C-S) _n -Polyethylene oxide, polyethyleneimine, and polyethylene sulfide represented by-. These may be branched as a main chain structure. Polymethyl methacrylate, polyvinylidene fluoride, polyvinylidene chloride, polycarbonate and the like are also preferable.
[0018]
When forming the polymer electrolyte layer 5, it is preferable to add a required plasticizer to the matrix polymer. As the preferred plasticizer, when the matrix polymer is hydrophilic, water, ethyl alcohol, isopropyl alcohol and a mixture thereof are preferable. When the matrix polymer is hydrophobic, propylene carbonate, dimethyl carbonate, ethylene carbonate, γ-butyrolactone is preferable. Acetonitrile, sulfolane, dimethoxyethane, ethyl alcohol, isopropyl alcohol, dimethylformamide, dimethylsulfoxide, dimethylacetamide, n-methylpyrrolidone, and mixtures thereof are preferred.
[0019]
The polymer electrolyte layer 5 is formed by dissolving an electrolyte in the matrix polymer. As the electrolyte, in addition to a metal salt that functions as a coloring material for display, a quaternary ammonium halide (F, Cl, Br, I), alkali metal halides (LiCl, LiBr, LiI, NaCl, NaBr, NaI, etc.), alkali metal cyanide, alkali metal thiocyanate, etc., and at least one kind selected from these A solution containing a supporting electrolyte is dissolved as an electrolyte. Here, examples of the metal ions constituting the metal salt that functions as a coloring material for display include bismuth, copper, silver, lithium, iron, chromium, nickel, cadmium, etc., and these can be used alone or in combination. Use. As the metal salt, any salt of these metals may be used. Examples of silver salts include silver nitrate, silver borofluoride, silver halide, silver perchlorate, silver cyanide, and silver thiocyanide. Can do.
[0020]
The polymer electrolyte layer 5 may be added with a coloring material in order to improve contrast. When the color due to metal deposition is black, the background color is preferably white, and a white material with high concealment is preferably introduced as the colorant. As such a material, coloring white particles can be used, and as the coloring white particles, titanium dioxide, calcium carbonate, silica, magnesium oxide, aluminum oxide and the like can be used.
[0021]
In this case, the mixing ratio of the white pigment is preferably about 1 to 20% by weight, more preferably about 1 to 10% by weight, and further preferably about 5 to 10% by weight in the case of using inorganic particles. This ratio is restricted because white pigments such as titanium oxide are not soluble in the polymer but only disperse, and as the mixing ratio increases, the white pigment aggregates, resulting in an optical density. This is because it becomes uneven. Moreover, since the white pigment has no ionic conductivity, an increase in the mixing ratio causes a decrease in the conductivity of the polymer electrolyte. Considering both, the upper limit of the mixing ratio is about 20% by weight.
[0022]
When inorganic particles are mixed in the polymer electrolyte layer 5 as a colorant as described above, the thickness of the polymer electrolyte layer 5 is preferably 10 to 200 μm, more preferably 10 to 100 μm, and still more preferably 10 to 10 μm. 50 μm. The thinner the polymer electrolyte layer 5 is, the smaller the resistance between the electrodes, so that the time required for color development and decoloration is shortened and the power consumption is reduced. However, when the thickness of the polymer electrolyte layer 5 is less than 10 μm, the mechanical strength is lowered, and problems such as pinholes and cracks occur. Moreover, when the thickness of the polymer electrolyte layer 5 is too thin, the amount of the inorganic particles mixed in may be reduced as a result, and whiteness (optical density) may not be sufficient.
[0023]
In addition, when using a pigment | dye as a coloring material mixed in the polymer electrolyte layer 5, as a ratio which mixes a coloring material, 10 weight% or less may be sufficient. This is because the coloring efficiency of the dye is much higher than that of the inorganic particles. Therefore, sufficient contrast can be obtained even with a small amount as long as the dye is electrochemically stable. As such a pigment, for example, an oil-soluble dye is preferable.
[0024]
The base substrate 3 provided on the back side is not necessarily transparent, and a substrate, a film, or the like that can reliably hold the row electrode 4 can be used. For example, it is possible to use a glass substrate such as a quartz glass plate and a white glass plate, a ceramic substrate, a paper substrate, and a wood substrate. Of course, the present invention is not limited to this, and a synthetic resin substrate or the like can also be used. Synthetic resin substrates include esters such as polyethylene naphthalate and polyethylene terephthalate, cellulose esters such as polyamide, polycarbonate, and cellulose acetate, fluoropolymers such as polyvinylidene fluoride and polytetrafluoroethylene-cohexafluoropropylene, and polyoxymethylene. Examples include polyether, polyacetal, polystyrene, polyethylene, polypropylene, polyolefins such as methylpentene polymer, and polyimides such as polyimide-amide and polyetherimide. When these synthetic resins are used as the base substrate, a rigid substrate that does not bend easily can be used, but a flexible film-like substrate can also be used.
[0025]
For the row electrode 4, a conductive material such as a metal material can be used. However, if the potential difference between the metal constituting the row electrode 4 and the metal deposited on the transparent column electrode 2 is large, charges are accumulated on the electrode in the colored state, and the movement of the charge occurs to color unintended pixels. There is a risk of it. In particular, when the potential difference exceeds the deposition overvoltage (threshold for simple matrix driving) when the metal is deposited, there is a possibility that the coloring occurs. Therefore, it is desirable to select a metal for the row electrode 4 such that the potential difference with the metal deposited as the coloring material is less than the deposition overvoltage (threshold). Ideally, the metal material of the row electrode 4 is in a state (metal state) before ionization of metal ions used in the color forming material. That is, for example, when silver precipitation / dissolution is used, silver is used for the row electrode 4, and the same metal as the metal deposited / dissolved is used for the row electrode 4. As a result, the potential difference does not occur when metal is deposited on the transparent column electrode 2.
[0026]
Hereinafter, a specific example of manufacturing the metal deposition type display device of the simple matrix driving method will be described.
First, a first electrode (display electrode) that is a striped electrode is formed. Here, a striped transparent electrode and an insulating film are formed on a polycarbonate substrate of 10 cm × 10 cm and a thickness of 0.2 mm according to the following procedure. Formed. The striped transparent electrodes had a stripe width of 150 μm and a pitch of 170 μm, and the size of the openings (portions not covered by the insulating film) was 140 μm square.
[0027]
First, an ITO film having a film thickness of 500 nm and a sheet resistance value of 12Ω / □ was formed on the polycarbonate substrate by sputtering. Next, a photoresist was applied on the ITO film, and the photoresist was formed in a desired stripe shape by a lithography method. Next, the polycarbonate substrate was eroded in an ITO etching solution, and the ITO film in a portion not covered with the photoresist was removed. Thereafter, the remaining photoresist was removed with an organic solvent such as acetone.
[0028]
Next, the TEOS (ethyl silicate: Si (OC ₂ H ₅ ) ₄ : Tetra-Ethoxyortho-Silicate) and O ₂ By the plasma CVD method using ₂ Was deposited to 200 nm. This SiO ₂ Photoresist is coated on the film, the photoresist is formed into a desired shape by lithography, and this substrate is eroded by a mixed solution of ammonium fluoride, hydrofluoric acid, etc. SiO ₂ The membrane was removed. Thereafter, the remaining photoresist was removed with an organic solvent such as acetone.
[0029]
The counter electrode as the second electrode was produced by the following procedure. Copper electrodes were formed in stripes on a base substrate made of polycarbonate, PET (polyethylene terephthalate), or an epoxy resin such as a glass epoxy resin used for a circuit board. The method for forming the striped copper electrode is as follows. First, copper was formed on the entire surface of the base substrate by sputtering or the like. Subsequently, a photoresist was coated on the copper electrode on the entire surface, covered with a stripe-shaped metal mask or a mask for blocking ultraviolet rays, and irradiated with ultraviolet rays. The portions of the photoresist and electrodes masked by the lithography method were removed by wet etching or dry etching so that the striped electrodes were insulated. Next, an electric field was applied to the formed stripe electrode, which was immersed in a solution in which silver or a desired metal was dissolved, and silver was deposited on the electrode by an electroplating method to produce a counter electrode.
[0030]
In the counter electrode, the thickness of copper is about 15 μm, the thickness of silver is also about 15 μm, and the total thickness is about 30 μm. Although there is an electroless method in which silver or metal is deposited without applying electrolysis, the electrolytic plating method is preferable because the deposited metal becomes thicker.
[0031]
In the base substrate, it is desirable to make the interval between pixels to be displayed as narrow as possible. Further, in the base substrate, the gap between the pixels is covered with a solid electrolyte, but it is preferable to use a white substrate as much as possible, assuming that the solid electrolyte can be seen through.
[0032]
Next, the production of the display electrode and the preparation and application of the solid polymer electrolyte include 1 part by weight of polyvinylidene fluoride having a molecular weight of about 350,000, 10 parts by weight of dimethyl sulfoxide, 1.7 parts by weight of silver iodide, sodium iodide. 1 part by weight was mixed and heated to 120 ° C. to prepare a uniform solution. Next, 0.2 part by weight of titanium dioxide having an average particle size of 0.5 μm was added thereto, and the mixture was uniformly dispersed with a homogenizer. After this was applied on the glass substrate with a doctor blade to a thickness of 20 μm, a common electrode as a second electrode described next was immediately bonded, and this was dried under reduced pressure at 110 ° C. and 0.1 MPa for 1 hour. A gelled solid polymer electrolyte was formed between the two electrodes. Next, the end face of the bonding was sealed with an adhesive.
[0033]
The produced display device was driven and the display characteristics were evaluated. When driving, a desired set of stripe-like electrodes is selected by a known method, and at the time of color development, an electric quantity of 2 μC per pixel is supplied to the display electrode for 0.1 second, causing a reduction reaction on the display electrode side and decoloring. Occasional oxidation with the same amount of electricity switched between colored [black] and colorless [white] displays. The reflectance when colorless [white] was 85%, and the optical density (OD) of the display portion when colored [black] was about 1.4 (reflectance 4%). Pixels that were not selected did not develop or lose color.
[0034]
The above is an example of the configuration of a simple matrix drive type metal deposition type display device, but if the active matrix method is used in which each pixel is driven by a circuit composed of one or more thin film transistors, screen rewriting is performed at a higher speed. Can be realized. FIG. 3 illustrates a configuration example of an active matrix display device.
[0035]
The active matrix display device also has a structure in which the electrolyte layer 13 made of a polymer electrolyte or the like is sandwiched between the transparent substrate 11 and the base substrate 12, as in the simple matrix display device. The constituent materials of the base substrate 12 and the electrolyte layer 13 are the same as those of the simple matrix display device. The electrode structure is very different from a simple matrix display device. First, a transparent electrode 14 is formed on the transparent substrate 11. The transparent electrode 14 is not formed in a stripe shape, but is formed on the entire surface of the transparent substrate 11 and serves as a common electrode. On the other hand, on the base substrate 12, dot-like pixel electrodes 15 corresponding to each pixel are arranged in a matrix, and a thin film transistor for driving is connected to each pixel electrode 15.
[0036]
FIG. 4 shows a circuit configuration of the active matrix display device. As described above, in the active matrix display device, the pixels 24 each including the thin film transistor 21, the pixel electrode 22, and the common electrode 23 are arranged in a matrix. Further, data line driving circuits 25a and 25b and a gate line driving circuit 26 for selectively driving each pixel 24 are provided. The data line drive circuits 25a and 25b and the gate line drive circuit 26 select a predetermined data line 28 or gate line 29 in accordance with a control signal from the signal control unit 27, and turn on / off each pixel 24. Switch.
[0037]
Next, a basic driving method of the display device will be described. For example, when a triangular wave voltage as shown in FIG. 5 is applied between the column electrode and the row electrode in a simple matrix type display device using the electrodeposition characteristic, a current-voltage transient response characteristic as shown in FIG. 6 is shown. FIG. 6 is an example of characteristics when the row electrode is an Ag electrode and silver ions and iodine ions are dissolved in the polymer electrolyte.
[0038]
Referring to FIG. 6, when a voltage is applied from zero to a minus side between the column electrode and the row electrode, silver does not precipitate for a while, and the threshold voltage V _th The silver starts to be deposited on the column electrode. In FIG. 6, the threshold voltage V _th It can be seen that the current accompanying the deposition starts flowing beyond As described above, each pixel has a strong characteristic mainly as a capacitor before deposition (white), and has a characteristic that the resistance value decreases as it deposits (black).
[0039]
Silver deposition is caused by the write voltage V corresponding to the peak of the triangular wave voltage. _w Once threshold voltage V _th If the voltage exceeds the threshold voltage V, it continues even if the voltage gradually decreases. _th It continues even if it falls below. The deposition of silver ends when the applied voltage is the holding voltage V _ke It is when it falls to. That is, once the threshold voltage V _th If a nucleus (seed) is formed beyond the threshold voltage V _th Silver deposition also occurs at the following voltages.
[0040]
On the other hand, when a reverse polarity (plus) voltage is applied between the column electrode and the row electrode, the dissolution of silver begins, and the erase voltage V _ith The silver deposited at the time of reaching disappears. When a voltage higher than this is applied, iodine is liberated and adheres to the electrode, resulting in a yellow coloration.
[0041]
Considering driving of a display device that exhibits current-voltage transient response characteristics as described above, the simplest is to apply a voltage exceeding the threshold voltage during address driving to deposit silver and write a pixel. . Hereinafter, for the sake of simplification of explanation, a basic driving method of a metal deposition type display device will be described by taking a monochrome display by 3 × 3 pixels shown in FIG. 7 as an example.
[0042]
FIG. 8 shows the threshold voltage V by adding a negative voltage. _th An example of a drive voltage waveform that displays using a deposition threshold voltage in a metal deposition type display device in which silver deposits on the column electrode when it becomes larger and silver dissolves when a positive voltage is applied. It is. In FIG. 8, each column electrode C ₁ , C ₂ , C ₃ Column voltage applied to each row electrode R ₁ , R ₂ , R ₃ And a low voltage applied to the pixel (C ₁ , R ₁ ), (C ₁ , R ₂ ), (C ₂ , R ₂ ) Applied voltage is shown.
[0043]
When displaying, each column electrode C ₁ , C ₂ , C ₃ Has a threshold voltage V _th Smaller signal write voltage pulse V _sig Each row electrode R ₁ , R ₂ , R ₃ Has a threshold voltage V _th Smaller selection voltage pulse V _sel And select from the top. At this time, the threshold voltage V is applied only to the pixels on which silver is deposited. _th Larger voltage (write voltage V _w ) (= V _sig -V _sel ), Silver is deposited on the transparent column electrode, and writing is performed.
[0044]
For example, pixel (C ₁ , R ₁ ), (C ₂ , R ₂ ), Column electrode C ₁ , C ₂ Signal write voltage pulse V _sig And row electrode R ₁ , R ₂ Selection voltage pulse V _sel As a result, the write voltage V _w Is added, and silver is deposited (written). On the other hand, the pixel (C ₁ , R ₂ ), Column electrode C ₁ Signal write voltage pulse V _sig And row electrode R ₂ Selection voltage pulse V _sel And the threshold voltage V _th Signal write voltage pulse below V _sig Or select voltage pulse V _sel Only one of them is added. Therefore, silver deposition does not occur and writing to the pixel is not performed.
[0045]
After writing, the display can be memorized by opening or shorting both the column electrode and the row electrode. The row electrode R ₁ , R ₂ , R ₃ The voltage for erasing at a predetermined timing -V _e And add a positive voltage V to each pixel. _e By adding, silver dissolves and is erased. The erasing voltage V _e Is the erase voltage V in FIG. _ith Set to the same or slightly lower value. Erasing voltage V _e Is the erase voltage V _ith If it exceeds, there is a risk of coloring.
[0046]
The display device is expected to be used for paper applications, that is, for reading books and documents, because a sufficient display can be obtained by reflection without having a light source. In addition, the function of paper is to write by hand. This is also an important function of paper as a tool to demonstrate human creativity. In order to realize handwriting input with a display device, for example, a touch panel is usually placed on the front side of the display device and written with a touch pen, and the positional information is sent to the display device as image information to display an image.
[0047]
However, since the display speed of the metal deposition type display device is slower than a CRT or a liquid crystal display device (for example, about 100 milliseconds), the output time corresponding to each pixel from the touch panel is short when writing quickly. (For example, about 10 milliseconds), and it is difficult to drive each pixel sufficiently. Specifically, for example, there is a tendency that it cannot be completely reversed from white display to black display.
[0048]
For example, consider a configuration in which a simple matrix drive type metal deposition type display device is combined with a tablet as position information detecting means. The tablet and the display device may be displayed in the same place as a result of overlapping writing, or may be electrically connected in different places. FIG. 9 shows a configuration example in which the method employed in a liquid crystal display device or the like is applied to a metal deposition type display device as it is. In this case, the position information 33 drawn by the pen 32 obtained from the tablet 31 enters the image memory (VRAM) 35 storing the screen information of the display device 34 and rewrites the data. Based on the rewritten image information, in this case, the entire screen is rewritten by XY scanning by the drive circuit 36 of a simple matrix.
[0049]
However, with this method, the entire screen is rewritten for each point drawn by the pen 32, and it becomes difficult for a display device with a slow display speed to follow the pen 32 and draw the screen. The metal deposition type display device has a low display speed, and as described above, the display time of one pixel is about 100 milliseconds. For example, in a display device in which the display time of one pixel is 100 milliseconds, a simple matrix having 100 lines requires 100 milliseconds × 100 = 10 seconds to rewrite the entire screen.
[0050]
Therefore, in the present invention, as shown in FIGS. 10 and 11, the voltage is directly applied to the X and Y electrode terminals 37 and 38 of the display device 34 from the position information (X, Y) 33 at each time point when the pen 32 is generated. Is applied, writing corresponding to the position of the pen 32 is performed in a short time. This utilizes the fact that a metal deposition type display device has a memory effect to hold an image, and an already written image remains even after energization (voltage application) is cut off. In the method of the present invention (method of performing direct drawing based on position information from the position information detecting means), for example, in a display device in which the display time of one pixel is 100 milliseconds, the pixel display of one pen position is performed. It can be done in 100 milliseconds.
[0051]
However, in a display device with high resolution, since the pixels are small, the handwriting time per pixel is usually quite fast, for example, 1 to 10 milliseconds, and there is a possibility that the display cannot catch up with the above method. is there. In such a case, display driving synchronized with handwriting is performed at a high speed capable of handling 1 to 10 milliseconds. At the same time, information on points written up to that point is stored in the image memory. Thereafter, after handwriting with the pen is finished, additional writing is performed based on information in the screen memory to obtain a predetermined contrast.
[0052]
The display by the above method is shown in FIGS. Also in this example, as in the previous example, first, as shown in FIGS. 12 and 13, the X, Y of the display device 34 is directly obtained from the position information (X, Y) 33 at each time point when the pen 32 is generated. By applying a voltage to the electrode terminals 37 and 38, writing corresponding to the position of the pen 32 is performed. However, at this time, it is not necessary to complete the writing. For example, a voltage exceeding a threshold voltage at which the crystal starts to precipitate may be applied for a short time to form a crystal serving as a nucleus. As a result, display driving can be performed at a much higher speed than when writing of each pixel is completed.
[0053]
In addition, if the writing following the handwriting as described above is only the formation of the crystal serving as the nucleus, the display density of the handwritten part is insufficient, but the display following the handwriting speed even if it is subtracted is Is useful. Moreover, the lack of density can be compensated by additional writing. That is, as shown in FIG. 12 and FIG. 13, simultaneously with the writing corresponding to the position of the pen 32, the position information 33 at each time point generated by the pen 32 is accumulated in the image memory (VRAM) 35. After the handwriting input is completed, as shown in FIG. 14, the entire screen is XY-scanned by the drive circuit 39 based on the accumulated full-screen information, and additional writing is performed.
[0054]
In a metal deposition type display device, each pixel written at high speed becomes conductive due to the hysteresis effect, so that the additional writing is uniform over the entire counter electrode of the screen, regardless of the normal matrix scan drive. It is also possible to increase the density of only the pixels handwritten in advance by applying a voltage (for example, 0.5 V below the threshold). Since current does not flow in pixels other than the handwritten pixels, there is no change, and by using such a phenomenon, additional writing that is extremely simple and fast can be performed. In this case, the image memory need not be used.
[0055]
The image by handwriting input can also be displayed superimposed on the external screen information. A display circuit in this case is shown in FIG. Also in this case, writing corresponding to the position of the pen 32 is performed by applying a voltage directly to the X and Y electrode terminals 37 and 38 of the display device 34 from the position information 33 at each time point when the pen 32 is generated. Is the same as the above examples. At this time, the entire screen is XY-scanned by the drive circuit 39 based on the external screen information 40, and external image information is displayed simultaneously. It is also possible to store the sum of the image information based on the position information 33 and the external screen information 40 in the image memory 35 as full screen information, and display it collectively by full screen XY scanning.
[0056]
The display device to which the present invention is applied and the driving method thereof have been described above. Needless to say, the present invention is not limited to these examples. For example, each of the above examples is an example of a metal deposition type electrochemical display device (electrodeposition display), but the pixels are selectively colored by energization, and the colored state is maintained even after the energization is cut off. Any display device can be applied, for example, an electrochromic display device or the like. The above handwritten display concept can be easily applied not only to the simple matrix driving method but also to the active matrix display method.
[0057]
【The invention's effect】
As is clear from the above description, according to the present invention, it is possible to electronically realize an operation of writing on paper by hand. At this time, the problem that the display speed is slow relative to the handwriting speed can be solved, and it is possible to achieve both speeding up of the handwriting display and improvement in contrast. Therefore, it is possible to realize a product having a new user interface such as an electronic notebook.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating an example of a simple matrix metal deposition type display device.
FIG. 2 is a schematic exploded perspective view showing an example of a simple matrix metal deposition type display device.
FIG. 3 is a schematic exploded perspective view showing an example of an active matrix metal deposition type display device.
FIG. 4 is a circuit diagram showing an example of a circuit configuration of an active matrix metal deposition type display device.
FIG. 5 is a waveform diagram showing a triangular wave voltage applied for examining a current-voltage transient response characteristic;
FIG. 6 is a characteristic diagram showing current-voltage transient response characteristics.
FIG. 7 is a schematic diagram of a 3 × 3 pixel panel.
FIG. 8 is a waveform diagram showing a driving voltage waveform in a basic driving method of a metal deposition type display device.
FIG. 9 is a schematic diagram illustrating an example of a handwriting display method.
FIG. 10 is a schematic diagram showing an example of a handwriting display method to which the present invention is applied.
FIG. 11 is a schematic diagram illustrating an example of a display circuit that directly drives a display panel based on position information.
FIG. 12 is a schematic diagram showing another example of a handwriting display method to which the present invention is applied.
FIG. 13 is a schematic diagram showing a state in which a display panel is directly driven based on position information.
FIG. 14 is a schematic diagram showing a state of additional writing.
FIG. 15 is a schematic diagram illustrating an example of a display circuit when handwritten display is performed over an existing image display.
[Explanation of symbols]
1,11 transparent substrate, 2 column electrode, 3,12 base substrate, 4 row electrode, 5 polymer electrolyte, 6 metal, 13 electrolyte layer, 14 transparent electrode, 15 pixel electrode, 31 tablet, 32 pen, 33 position information, 34 display device, 35 image memory,

Claims (16)

In the display device in which the pixels are selectively colored by energization and the coloring state is maintained even after the energization is interrupted,
It has position information detection means for detecting the coordinate position on the screen, and direct drawing is performed based on the position information from the position information detection means ,
A display device , wherein after the direct drawing, additional writing is performed by applying a uniform voltage across the entire surface . The display device according to claim 1, wherein a voltage is applied to an electrode of a pixel corresponding to the position information in synchronization with detection of the position information.   2. A storage unit for storing full screen information from the position information detection unit, and after the direct drawing, additional writing is performed based on the full screen information stored in the storage unit. The display device described.   2. The display device according to claim 1, wherein direct drawing is performed based on the position information from the position information detecting means, superimposed on the image display based on the external image information. 5. The display device according to claim 4, further comprising switching means for switching between image display based on the external image information and direct drawing based on position information from the position information detection means. 5. The display device according to claim 4, further comprising storage means for storing the sum of the full screen information from the position information detection means and the external image information.   The display device according to claim 1, wherein coloring is performed by metal deposition.   2. The display device according to claim 1, wherein the display device is driven by a simple matrix system or an active matrix system.   The display device according to claim 1, wherein the position information detecting means is a touch panel or a tablet. In the driving method of the display device in which the pixels are selectively colored by energization and the colored state is maintained even after the energization is interrupted,
Draw directly based on the position information from the position information detection means ,
A method for driving a display device, wherein after the direct drawing, additional writing is performed by applying a uniform voltage across the entire surface . 11. The method for driving a display device according to claim 10 , wherein a voltage is applied to an electrode of a pixel corresponding to the position information in synchronization with the detection of the position information. 11. The method of driving a display device according to claim 10, wherein the full screen information from the position information detecting means is saved, and after the direct drawing, additional writing is performed based on the saved full screen information. 11. The method of driving a display device according to claim 10 , wherein an image based on the position information from the position information detecting means is directly drawn on the image display based on the external image information. 14. The method of driving a display device according to claim 13 , wherein the sum of the full screen information from the position information detecting means and the external image information is stored and displayed together. 11. The method for driving a display device according to claim 10 , wherein the pixel is colored by depositing metal by energization. 11. The display device driving method according to claim 10 , wherein driving is performed by a simple matrix system or an active matrix system.

Images