JP4894318B2 - Display driving device and display device including the same - Google Patents

Description

  The present invention relates to a display driving device and a display device including the same.

  A display device (hereinafter referred to as an electrochromic display device) that utilizes a phenomenon in which metal ions in an electrolytic solution are precipitated or dissolved by an oxidation-reduction reaction by injecting electric charge into the electrolytic solution in which metal ions are dissolved. Various proposals have been made.

In order to inject charges into the display unit of this type of display device, conventionally, charges are injected by applying a voltage pulse of a rectangular wave or a voltage pulse of a triangular wave or a sawtooth wave. . For example, in Patent Document 1, coloring and decoloring are performed by applying a rectangular wave voltage pulse to the display unit. Here, when a rectangular wave pulse of a certain time is applied to the display device from a display drive device that performs display drive of the display portion, if the wiring resistance to the display portion can be ignored, the resistance value in the display portion at the time of color development becomes the display area. It is known to be inversely proportional. It is also known that the resistance value is inversely proportional to the display area in the same manner as in the color development until the color erase is completed even at the time of color erase. Therefore, if a constant voltage is applied for a certain period of time, it is possible to inject an amount of charge that is substantially proportional to the display area.
JP 2000-142223 A

  Here, in the case of erasing in the display portion of the electrochromic display device, the resistance value changes (increases) when a certain degree of erasing progresses, unlike the case of coloring, and the current flows when a constant voltage is applied. It is known to decrease. Since the amount of charge required for color erasing is the same as that for color development, in order to compensate for the decrease in the amount of charge due to the decrease in current, should the voltage for color erasure be set higher than that for color development? Alternatively, it is necessary to lengthen the voltage application time. At this time, since the voltage drop occurs due to the wiring resistance between the display unit and the display driving device, the contact resistance between the circuits, etc., the flowing current changes greatly. Need to be adjusted. However, generally, the values of wiring resistance, contact resistance between circuits, and the like vary greatly, and it is not easy to make these values constant.

  The present invention has been made in view of the above circumstances, and in a display device having a display unit having a characteristic in which a resistance value is changed by application of a current, the display unit capable of accurately driving the display unit, and the display device An object of the present invention is to provide a display driving device used in such a display device.

In order to achieve the above object, the display driving apparatus according to the first aspect of the present invention is a display driving apparatus that drives a display unit whose display state is controlled by application of current and whose resistance value changes by application of the current. A resistance detecting means for detecting a change in the resistance value of the display section, a constant current applying means for applying a constant current to the display section when controlling a display state of the display section, and the constant current applying means. Control means for controlling the application of the constant current to the display unit based on a change in the resistance value detected by the resistance detection means, the resistance detection means, the change in the resistance value, Voltage detecting means for detecting a change in voltage value of the voltage generated in the display unit by application of the constant current by the constant current applying means, and the control means is configured such that the voltage value is equal to a preset reference value. The group When the value is exceeded, control is performed to decrease the current value of the constant current applied to the display unit so that the voltage value is less than the reference value, and the voltage value is the constant current. When the constant current is applied to the display unit while performing control to decrease the current value of the constant current, the voltage value no longer increases due to the application of the constant current. in characterized Rukoto to terminate the application of the constant current to the display unit.

In order to achieve the above object, a display device according to the second aspect of the present invention includes a display unit having a display unit in which a display state is controlled by applying a current and a resistance value is changed by applying the current. A resistance detection unit that detects a change in the resistance value of the display unit; a constant current application unit that applies a constant current to the display unit when controlling the display state of the display unit; and Control means for controlling the application of the constant current from the constant current application means to be applied to the display unit based on a change in the resistance value detected by the resistance detection means, the resistance detection means, Voltage detecting means for detecting a change in the resistance value as a change in a voltage value of a voltage generated in the display means by application of the constant current by the constant current applying means; Set reference value When the voltage becomes equal or exceeds the reference value, the current value of the constant current applied to the display unit is decreased so that the voltage value becomes lower than the reference value. When the value rises due to the application of the constant current, the application of the constant current to the display unit is continued while performing control to decrease the current value of the constant current, and the voltage value rises due to the application of the constant current characterized Rukoto to terminate the application of a constant current to the display unit at the time when no longer occurred.
In order to achieve the above object, a display driving apparatus according to a third aspect of the present invention is a display driving apparatus that drives a display unit whose display state is controlled by application of current and whose resistance value is changed by application of current. A resistance detecting means for detecting a change in the resistance value of the display section, a constant current applying means for applying a constant current to the display section when controlling a display state of the display section, and the constant current applying means. Control means for controlling the application of the constant current to the display unit based on a change in resistance value detected by the resistance detection means, and the resistance detection means detects the change in resistance value. Voltage detecting means for detecting a change in voltage value of the voltage generated in the display unit by application of the constant current by the constant current applying means, and the control means sets the voltage value to a preset reference value. Equals or the When the reference value is exceeded, control is performed to reduce the current value of the constant current applied to the display unit so that the voltage value becomes lower than the reference value. When the current is increased by application of current, the constant current is applied to the display unit while controlling to decrease the current value of the constant current, and the display unit of the constant current is decreased to a lower level. When the voltage value when the constant current is applied continuously falls below the reference value for a predetermined period, the application of the constant current to the display unit is terminated. It is characterized by.
In order to achieve the above object, a display device according to a fourth aspect of the present invention includes a display unit having a display unit in which a display state is controlled by applying a current and a resistance value is changed by applying the current; A resistance detection unit that detects a change in the resistance value of the display unit, a constant current application unit that applies a constant current to the display unit when controlling the display state of the display unit, and a voltage that is applied when the color is erased Control means for controlling the application of the constant current from the constant current application means to the display unit based on a change in resistance value detected by the resistance detection means, and the resistance detection means Voltage detection means for detecting a change in resistance value as a change in voltage value of the voltage generated in the display means by application of the constant current by the constant current application means, and the control means is detected by the voltage detection means The voltage value to be When the current value rises and the voltage value exceeds a preset reference value, the current value of the constant current applied to the display means is reduced to such an extent that the voltage value becomes lower than the reference value. While continuing the application of the constant current to the display unit, when the voltage value when the constant current is applied continuously falls below the reference value for a predetermined period, the display unit to the display unit The application of the constant current is terminated.

  According to the present invention, a constant current is applied to a display unit having a characteristic in which a resistance value is changed by application of a current, and the display unit is driven based on a change in the resistance value of the display unit according to the applied constant current. By controlling the application of the constant current, the display unit can be appropriately driven.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of a display device to which a display driving device according to an embodiment of the present invention is applied. FIG. 2 is a diagram illustrating an arrangement example of display segments of the display panel. Here, in the following description, a case where the display device is an electrochromic display device will be described. However, the method of the present embodiment is not limited to the electrochromic display device, and coloring and decoloring driving can be performed by applying a current. The present invention can be applied to all display devices that have such characteristics that the resistance value of the display portion is changed by application of current.

  The electrochromic display device 1 shown in FIG. 1 includes a display panel 10, a constant current application circuit 20, a segment profile memory 30, and a system interface 40. In the electrochromic display device according to the present embodiment, as shown in FIG. 1, the display panel 10 has a plurality of display segments, and is driven by applying a constant current to each display segment from a constant current applying circuit 20. In particular, the current value of the current applied to each display segment is set to a current value proportional to the area of each display segment based on the value stored in the segment profile memory 30. Yes.

  The display panel 10 as a display means is a segment type display panel, and a plurality of display segments as a display unit are arranged, for example, as shown in FIG. Here, the example of FIG. 2 is an arrangement example of display segments when the display panel 10 is used as a display panel for displaying a display pattern such as alphabets and numbers, and includes seven display segments (display segments 10). -1 to 10-7) are arranged in an 8-character form. Note that the shape, number, and arrangement of the display segments are not limited to those shown in FIG. 2, and can be appropriately changed according to the specifications required for the display panel.

FIG. 3 is a cross-sectional view taken along the line AA for explaining the configuration of the display segment of FIG. Here, the cross-sectional view of FIG. 2 is a cross-sectional view of the display segment 10-1, but the configuration of the other display segments is basically the same as that described in FIG.
As shown in FIG. 3, in the display segment, two electrodes 10-11 and 10-12 are arranged in parallel, and an electrolytic solution 10 in which metal is dissolved between the electrodes 10-11 and 10-12. −13 is satisfied, and these are sealed with a sealing material 10-14. Furthermore, the glass substrate 10-15 for protecting a display segment is affixed on the back surface of the electrode 10-11. Here, the electrode 10-11 is a transparent electrode having transparency, and for example, an indium tin oxide (ITO) electrode is used. The electrode 10-12 may be a transparent electrode or an opaque electrode. For example, a copper (Cu) electrode is used as the electrode 10-12. Furthermore, the electrolytic solution 10-13 is an electrolytic solution in which, for example, Bi and Cu are dissolved. In addition, the material shown here is an example and can be changed suitably. For example, the metal to be dissolved in the electrolytic solution is not limited to Bi, but may be silver (Ag) or the like. Various solutions such as odorous acid, hydrochloric acid, and iodic acid can be used for dissolving Bi and Cu. Furthermore, as the electrolytic solution 10-13 between the electrode 10-11 and the electrode 10-12, a wet cake sheet holding the electrolytic solution may be used.

  When a negative charge is injected into the display segment configured as shown in FIG. 3, Bi ions in the electrolytic solution are reduced and deposited on the electrode 10-11. As a result, the display segment is colored black. Conversely, when a positive charge is injected into the display segment, Bi deposited on the electrode 10-11 is oxidized and dissolved in the electrolytic solution. As a result, the display segment that has been colored black is erased.

  The constant current application circuit 20 is provided corresponding to each of the plurality of display segments constituting the display panel 10 by the number of display segments. By applying a constant current to each display segment, the display segments are colored or erased. The charge for injecting is injected. Here, as shown in FIG. 1, the constant current application circuit 20 includes a coloring pulse generator 20-1, an erasing pulse generator 20-2, a constant current driver 20-3, and a voltage detection circuit 20-4. It is composed of Each circuit of the constant current application circuit 20 and its operation will be described in detail later.

  The segment profile memory 30 stores the value of the area of each display segment, or the current value designation data necessary for appropriate color development corresponding to the area of each display segment, corresponding to each display segment. It is a memory for. In the following description, it is assumed that the current value designation data corresponding to the area of each display segment is stored in the segment profile memory 30, but the value of the area of each display segment is stored, for example, the coloring pulse generator 20 -1 and the decoloring pulse generator 20-2 may have a function of converting into corresponding current value designation data. Then, the segment profile memory 30 receives the address signal from the system interface 40, and converts the current value designation data stored in the address into the coloring pulse generator in the constant current application circuit 20 connected to the corresponding display segment. 20-1 and the decoloring pulse generator 20-2. The segment profile memory 30 is preferably a nonvolatile memory such as an EPROM or a flash ROM. By configuring the segment profile memory 30 with a non-volatile memory, it is possible to retain the stored contents even when the circuit power is turned off.

  Upon receiving an instruction to display or hide the display panel 10 from a CPU (not shown), the system interface 40 develops or erases the display segment corresponding to the instruction. For this purpose, the system interface 40 outputs the pulse width designation data to the coloring pulse generator 20-1 and the decoloring pulse generator 20-2 in the corresponding constant current application circuit 20, and also displays the display segment for coloring or decoloring. The address signal corresponding to the address where the current value designation data corresponding to is stored is output to the segment profile memory 30.

Next, the constant current application circuit 20 will be described in more detail.
FIG. 4 is an example of a circuit block diagram in the case where the decoloring pulse generator 20-2 is configured by a sequential logic circuit. As shown in FIG. 4, the decoloring pulse generator 20-2 includes a pulse width register 20-21, a current value register 20-22, a DA converter 20-23, a down counter 20-24, and an analog switch 20. -25.

The pulse width register 20-21 receives pulse width designation data for designating the pulse width of the decoloring pulse from the system interface 40 and holds the data.
The current value register 20-22 receives current value designation data corresponding to each display segment from the segment profile memory 30, and holds the data. The DA converter 20-23 converts the current value designation data held in the current value register 20-22 into an analog voltage signal.

  The down counter 20-24 receives a START pulse from the system interface 40 at the time of decoloring, reads the value held in the pulse width register, and counts down this value at regular time intervals, and sends an ON or OFF signal to the analog switch 20- To 25. That is, the down counter 20-24 outputs an ON signal when the count value is not 0, and outputs an OFF signal when the count value becomes 0. The analog switch 20-25 is connected to the DA converter 20-23 and the positive power source + V, and is turned on when receiving an ON signal from the down counter 20-24, and the output of the DA converter 20-23 is constant current driver 20-. 3 and when the OFF signal is received, the voltage value + V is input to the constant current driver 20-3.

  With such a configuration, the analog switch 20-25 is turned on only while the down counter 20-24 is counting, so that the voltage value and pulse width designation data obtained by the DA converter 20-23 are designated as a result. A decoloring pulse having a predetermined pulse width is input to the constant current driver 20-3. When the down counter 20-24 finishes counting, the analog switch 20-25 is turned OFF, and the voltage value + V is input to the constant current driver 20-3.

  Although FIG. 4 shows the configuration of the decoloring pulse generator 20-2, the coloring pulse generator 20-1 can also be realized with a circuit configuration substantially similar to that of the decoloring pulse generator 20-2. However, in the coloring pulse generator 20-1, the power source connected to the analog switch is not a positive power source but a negative power source -V. In the coloring pulse generator 20-1, by changing the pulse width, the display segment can be colored not only in the complete coloring state and the complete erasing state but also in the intermediate state. As a result, gray scale display is possible.

  Note that the functions of the coloring pulse generator 20-1 and the decoloring pulse generator 20-2 may be realized by arithmetic processing such as a microcomputer.

  FIG. 5 is a diagram illustrating an example of a circuit constituting the constant current driver 20-3 and the voltage detection circuit 20-4. FIG. 6 is a diagram showing the wiring resistance between the constant current application circuit and the display segment. The constant current driver 20-3 includes a negative direction constant current applying unit including an operational amplifier 20-31, a MOS transistor 20-32, and a resistor 20-33, an operational amplifier 20-34, and a MOS transistor 20-35. And a positive direction constant current applying means comprising resistors 20-36. Further, the voltage detection circuit 20-4 is constituted by, for example, an AD converter.

  In FIG. 5, the output (coloring pulse or -V) from the coloring pulse generator 20-1 is input to the non-inverting input terminal of the operational amplifier 20-31. The output terminal of the operational amplifier 20-31 is connected to the gate of the MOS transistor 20-32. The source of the MOS transistor 20-32 is connected to the inverting input terminal of the operational amplifier 20-31 and one end of the resistor 20-33. ing. Furthermore, the other end of the resistor 20-33 is connected to a negative power source -V. Further, the output (erasing pulse or + V) from the decoloring pulse generator 20-2 is input to the non-inverting input terminal of the operational amplifier 20-34. The output terminal of the operational amplifier 20-34 is connected to the gate of the MOS transistor 20-35, and the source of the MOS transistor 20-35 is connected to the inverting input terminal of the operational amplifier 20-34 and one end of the resistor 20-36. ing. Further, the other end of the resistor 20-36 is connected to a positive power supply + V.

  The drains of the MOS transistors 20-32 and 20-35 are commonly connected to the output terminal of the constant current driver 20-3. The output terminal of the constant current driver 20-3 is connected to the display segment 10-1 as shown in FIG. 6 and also to the voltage detection circuit 20-4. The resistance indicated by reference numeral 10-16 in FIG. 6 is resistance due to wiring resistance, contact resistance, or the like between the constant current driver 20-3 and the display segment 10-1.

  Hereinafter, the operation of the constant current driver 20-3 will be described. Note that the negative direction constant current applying means and the positive direction constant current applying means are the same in the basic operation except that the polarity of the input voltage and the direction of the output current are opposite. Only the operation of the constant current applying means will be described.

  In the configuration shown in FIG. 5, when the display segment is decolored, the decoloring pulse from the decoloring pulse generator 20-2 is input to the non-inverting input terminal of the operational amplifier 20-31. By the input of the decoloring pulse, the output of the operational amplifier 20-34 is applied to the gate of the MOS transistor 20-35, and the MOS transistor 20-35 is turned on. Thereby, the current corresponding to the voltage value of the decoloring pulse is directed from the output terminal of the constant current driver 20-3 toward the positive power supply + V (that is, from the display segment 10-1 toward the constant current driver 20-3). ) Flowing. A voltage generated according to this current and a load (such as a display segment resistance or wiring resistance) connected to the constant current driver 20-3 is detected by the voltage detection circuit 20-4. As will be described later, a CPU (not shown) determines whether or not the detected voltage value exceeds a predetermined reference value (reference value voltage) Vt. Here, for example, the output signal of the voltage detection circuit 20-4 is binarized depending on whether or not the detected voltage value exceeds a predetermined reference value voltage Vt, and this binarized signal is converted into the system interface 40. May be input to a CPU (not shown) via

  Here, as shown in FIG. 5, since the positive direction constant current applying means constitutes a constant current driver, the positive direction constant current applying means is applied to the display segment 10-1 regardless of the voltage change in the display segment 10-1. The amount of current is constant. In this way, positive charges are injected into the display segment 10-1.

  When + V is input from the decoloring pulse generator 20-2, the output of the operational amplifier 20-31 becomes 0. Accordingly, the MOS transistor 20-35 is turned off, and the constant current driver. The current output from 20-3 becomes zero.

  When a coloring pulse is input from the coloring pulse generator 20-1 to the negative direction constant current applying means, the output terminal of the constant current driver 20-3 is directed to the negative power source -V (that is, the constant current). Current flows from the driver 20-3 toward the display segment 10-1.

  FIG. 7 is a diagram showing a current applied from the constant current application circuit 20 to the display segment at the time of decoloring, a voltage generated by the current application, and a change in resistance due to the current application. In FIG. 7, the upper side of the drawing is the positive direction, and the lower side of the drawing is the negative direction.

When a negative constant current (current in the direction from the display segment 10-1 to the constant current driver 20-3) pulse designated by the pulse width designated by the pulse width designation data and the current value designation data is applied, A negative charge corresponding to applied current × application time is injected into the display segment, and color development occurs. Here, the amount of electric charge necessary for properly coloring the display segment is about 30 mC / cm ² in the case of an electrolytic solution mainly composed of Ag or Bi, but in this embodiment, it is applied to the display segment. By making the application time of the current to be variable, the amount of charge injected into the display segment can be accurately controlled. Further, when a pulse having a pulse width specified by the pulse width specifying data and a positive constant current specified by the current value specifying data (current in the direction from the constant current driver 20-3 to the display segment 10-1) is applied. Then, a positive charge corresponding to the applied current × application time is injected into the display segment, and decoloring occurs.

  Here, the amount of current that flows during color development or color erasing is such that the voltage generated in the display segment 10-1 by this current is higher than the voltage required to color or color the display segment, and the display segment It should be lower than the limit voltage that is the limit voltage that does not break down. In particular, at the time of erasing, as shown in FIG. 7, the resistance value of the display segment starts to increase when the erasing progresses to some extent. Therefore, when the color is erased, a change in the resistance value is detected, and when an increase in the resistance value is detected, the current applied to the display segment is reduced to suppress an increase in voltage generated in the display segment. To do. Here, in this embodiment, the voltage detection circuit 20-4 detects a change in the resistance value of the display segment as a voltage change.

  That is, a reference value voltage Vt lower than the limit voltage is set in advance, and the voltage detected by the voltage detection circuit 20-4 is equal to or exceeds the reference value voltage Vt (FIG. 7). At time A). Here, the reference value voltage Vt is preferably set for each display segment.

  Here, since the display segment has not yet reached complete erasing at the time A, additional erasing is performed for the period B after the time A. However, since the resistance value of the display segment continuously increases during the additional decoloring, the voltage detected by the voltage detection circuit 20-4 does not exceed the reference value voltage Vt in FIG. As shown, erasing is performed while the applied current is decreased for a while. Thus, the voltage applied to the display segment during the additional decoloring is controlled so as not to exceed the reference value voltage Vt.

  As shown at time C in FIG. 7, the increase in the resistance value of the display segment at the time of erasing has a characteristic that the increase in the resistance value stops when the erasing operation is completed. Therefore, in this embodiment, the period B during which additional erasing is performed is a period from when the resistance value starts to increase until the increase stops. That is, the voltage value detected by the voltage detection circuit 20-4 is equal to or exceeds the reference value voltage Vt, and the reference value voltage Vt is not exceeded even if the applied current is not decreased from the time when the decrease of the applied current is started. Period (time C in FIG. 7). By performing additional erasing only during this period, the balance between color development and erasing can be maintained, resulting in excessive erasing in the erasing drive after natural erasing, or color residue due to lack of erasing. Can be prevented more reliably.

  Here, in the embodiment described above, the change in the resistance value of the display segment is detected as a change in the voltage value and the applied current is controlled. However, the resistance value may be detected and the applied current may be controlled. good.

  Further, in the above-described embodiment, the voltage detection by the voltage detection circuit 20-4 may be to always detect the voltage value during decoloring, and the voltage is detected at certain time intervals (for example, every 1 ms). A value may be detected. In the latter case, the voltage detection circuit 20-4 determines whether the value of the voltage detected at the next detection exceeds the reference value voltage Vt after reducing the current at the time of additional decoloring. If so, the current is reduced. If the detected voltage value does not exceed the reference value voltage Vt, it is determined that the resistance value has stopped increasing, and the decoloring is terminated at that point.

  In addition, the time interval for detecting the voltage value may be a fixed time during the decoloring period.For example, the voltage value may be changed during the period when the resistance value changes gradually after the decoloring starts. The detection interval may be set to be relatively long, and the voltage value detection interval may be shortened in a period in which the change in the resistance value after the detected voltage value exceeds the reference value voltage Vt becomes steep. . In this way, it is easy to find the end point of erasing, so the time until the end of erasing can be shortened.

  In addition, there may be a case where the voltage value detected by the voltage detection circuit 20-4 does not exceed the reference value voltage value Vt even though it is not originally the end point of decoloring due to circuit noise or the like. Even if the reference value voltage value Vt is not exceeded, it is more preferable that the color erasure is not terminated immediately at that time but the color erasure is terminated when the state is continued for a predetermined period.

  Furthermore, although the above-described embodiment describes a segment type display panel, the method of the above-described embodiment can also be applied to a dot matrix type display panel. However, in the case of the dot matrix method, since the areas of the individual display portions are equal, the segment profile memory 30 is not necessarily required, and the reference value Vt need not be set for each display segment.

  According to the present embodiment described above, the display unit is not destroyed due to a voltage increase due to a change in the resistance value of the display unit, and is over-erased even in the erasing drive after natural erasing. Can be suppressed. In addition, additional erasing after erasing can prevent color remaining due to lack of erasing.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are naturally possible within the scope of the gist of the present invention.

  Further, the above-described embodiments include various stages of the invention, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be extracted as an invention.

1 is a block diagram illustrating a configuration of an electrochromic display device to which a display driving device according to an embodiment of the present invention is applied. It is a figure which shows the example of arrangement | positioning of a display segment. It is sectional drawing for demonstrating the structure of a display segment. It is an example of a circuit block diagram when the decoloring pulse generator is configured by a sequential logic circuit. It is a figure which shows an example of the circuit which comprises a constant current driver and a voltage detection circuit. It is a figure shown about wiring resistance between a constant current application circuit and a display segment. It is a figure which shows the change of the resistance by the electric current applied to a display segment from the constant current application circuit at the time of decoloring, the voltage generated by an electric current application, and an electric current application.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Display panel 10-1 to 10-7 ... Display segment 10-11, 10-12 ... Electrode 10-13 ... Electrolytic solution 10-14 ... Sealing material 10-15 ... Glass substrate 20 ... Constant current application circuit 20- DESCRIPTION OF SYMBOLS 1 ... Color development pulse generator 20-2 ... Decoloration pulse generator 20-3 ... Constant current driver 20-4 ... Voltage detection circuit 20-21 ... Pulse width register 20-22 ... Current value register 20-23 ... DA converter 20 -24 ... down counter 20-25 ... analog switches 20-31 and 20-34 ... operational amplifiers 20-32 and 20-35 ... MOS transistors 20-33 and 20-36 ... resistors 30 ... segment profile memory 40 ... system interface

Claims (12)

In a display driving device that drives a display unit in which a display state is controlled by application of a current and a resistance value changes by application of the current.
Resistance detection means for detecting a change in the resistance value of the display unit;
A constant current applying means for applying a constant current to the display unit when controlling the display state of the display unit;
Control means for controlling the application of the constant current from the constant current application means to the display unit based on a change in resistance value detected by the resistance detection means;
Equipped with,
The resistance detection means includes a voltage detection means for detecting a change in the resistance value as a change in a voltage value of a voltage generated in the display unit by application of the constant current by the constant current application means,
The control means decreases the current value of the constant current applied to the display unit when the voltage value becomes equal to or exceeds a preset reference value, and the voltage value is When the voltage value rises due to the application of the constant current, the control is performed to reduce the current value of the constant current to the display unit while performing the control to decrease the current value of the constant current. continuing the application, wherein the display driving apparatus according to claim Rukoto to terminate the application of a constant current to the display unit at the time the increase of the voltage value due to the application of the constant current no longer occurs. The display driving apparatus according to claim 1 , wherein the voltage detection unit detects the voltage value at predetermined time intervals. The voltage detecting means reduces the value of the time interval in the period in which the change amount of the voltage value is large with respect to the value of the time interval in the period in which the change amount of the voltage value due to the application of the constant current is small. The display driving device according to claim 2 , wherein The control means terminates the application of the constant current to the display unit when the voltage value due to the application of the constant current continuously falls below the reference value for a predetermined period. The display driving device according to claim 1 . The display unit includes an electrolytic solution in which a metal is dissolved, and an electrode for injecting electric charge into the electrolytic solution,
The constant current applying means applies the constant current to the electrode of the display unit and injects electric charge into the electrolytic solution through the electrode, thereby precipitating the metal in the electrolytic solution to cause color development, and the electrolytic solution The display driving device according to claim 1, wherein the deposited metal is dissolved and decolored by injecting a charge having a polarity opposite to that of the charge. A display unit having a display unit in which a display state is controlled by application of a current and a resistance value is changed by application of the current;
Resistance detection means for detecting a change in the resistance value of the display unit;
A constant current applying means for applying a constant current to the display unit when controlling the display state of the display unit;
Control means for controlling the application of the constant current from the constant current application means applied during the decoloring to the display unit based on a change in resistance value detected by the resistance detection means;
Equipped with,
The resistance detection means includes a voltage detection means for detecting a change in the resistance value as a change in a voltage value of a voltage generated in the display means by application of the constant current by the constant current application means,
The control means decreases the current value of the constant current applied to the display unit when the voltage value becomes equal to or exceeds a preset reference value, and the voltage value is When the voltage value rises due to the application of the constant current, the control is performed to reduce the current value of the constant current to the display unit while performing the control to decrease the current value of the constant current. continuing the application, said display device comprising Rukoto to terminate the application of a constant current to the display unit at the time the increase of the voltage value due to the application of the constant current no longer occurs. The display device according to claim 6 , wherein the voltage detection unit detects the voltage value at predetermined time intervals. The voltage detecting means reduces the value of the time interval in the period in which the change amount of the voltage value is large with respect to the value of the time interval in the period in which the change amount of the voltage value due to the application of the constant current is small. The display device according to claim 7 , wherein the display device is characterized. The control means terminates the application of the constant current to the display unit when the voltage value due to the application of the constant current continuously falls below the reference value for a predetermined period. The display device according to claim 6 . The display unit includes an electrolytic solution in which a metal is dissolved, and an electrode for injecting electric charge into the electrolytic solution,
The display device applies the constant current to the electrode of the display unit from the constant current applying unit, and charges are injected into the electrolytic solution through the electrode to deposit a metal in the electrolytic solution. 7. The electrochromic display device according to claim 6 , wherein the electrochromic display device develops a color and dissolves the deposited metal by injecting a charge having a polarity opposite to the charge into the electrolyte solution. Display device. In a display driving device that drives a display unit in which a display state is controlled by application of a current and a resistance value changes by application of the current.
Resistance detection means for detecting a change in the resistance value of the display unit;
A constant current applying means for applying a constant current to the display unit when controlling the display state of the display unit;
Control means for controlling the application of the constant current from the constant current application means to the display unit based on a change in resistance value detected by the resistance detection means;
Comprising
The resistance detection means includes a voltage detection means for detecting a change in the resistance value as a change in a voltage value of a voltage generated in the display unit by application of the constant current by the constant current application means,
The control means decreases the current value of the constant current applied to the display unit when the voltage value becomes equal to or exceeds a preset reference value, and the voltage value is When the voltage value rises due to the application of the constant current, the control is performed to reduce the current value of the constant current to the display unit while performing the control to decrease the current value of the constant current. Continue application, continue application of the constant current to the display unit while decreasing to a lower level, and the voltage value when the constant current is applied continues for a predetermined period of time to the reference value The display driving device is characterized in that the application of the constant current to the display unit is terminated when the value is lower than. A display unit having a display unit in which a display state is controlled by application of a current and a resistance value is changed by application of the current;
Resistance detection means for detecting a change in the resistance value of the display unit;
A constant current applying means for applying a constant current to the display unit when controlling the display state of the display unit;
Control means for controlling the application of the constant current from the constant current application means applied during the decoloring to the display unit based on a change in resistance value detected by the resistance detection means;
Comprising
The resistance detection means includes a voltage detection means for detecting a change in the resistance value as a change in a voltage value of a voltage generated in the display means by application of the constant current by the constant current application means,
The control means increases the voltage value detected by the voltage detection means by the application of the constant current, and the constant current applied to the display means when the voltage value exceeds a preset reference value. While continuing to apply the constant current to the display unit while decreasing the current value to the extent that the voltage value is lower than the reference value, the voltage value when the constant current is applied is for a predetermined period, The display device characterized in that, when the reference value is continuously decreased, application of the constant current to the display unit is terminated.

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