JP4923777B2 - Electrochromic display device and display driving device - Google Patents

Description

  The present invention relates to an electrochromic display device and a display driving device.

  Various display devices (hereinafter referred to as electrochromic display devices) have been proposed that utilize a phenomenon in which a solute in an electrolytic solution is precipitated or dissolved by an oxidation-reduction reaction by injecting electric charge into the electrolytic solution. For example, in the case of an electrochromic display device using bismuth (Bi) as a main raw material, when a negative charge is injected into the electrolyte from a transparent electrode such as indium tin oxide (ITO), Bi ions in the electrolyte are reduced. It deposits on the transparent electrode, and the part develops a black color. Conversely, when a positive charge is injected from the transparent electrode into the electrolytic solution, Bi deposited on the transparent electrode is oxidized and dissolved in the electrolytic solution, and the portion is decolored.

  In this type of electrochromic display device, the amount of solute deposited depends on the amount of charge injected into the electrolyte, so the larger the display area, the greater the amount of solute deposited by injecting more charges. Must.

In order to inject charges according to the area of the display portion in this manner, conventionally, charges are injected by applying a rectangular wave voltage pulse, or applying a triangular wave or sawtooth wave voltage pulse. Yes. 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 for a certain period of time is applied to the display unit from a display drive device that performs display drive of the display unit, if the wiring resistance to the display unit can be ignored, the resistance value in the display unit during color development is 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

  By the way, when a large current is continuously passed through the electrolytic solution during the color development step in the electrochromic display device (when a large amount of negative charge is injected from the transparent electrode into the electrolytic solution), the terminal voltage of the electrochromic display device Becomes larger on the negative side. Therefore, in this case, crystals precipitated on the transparent electrode grow rapidly. For this reason, the crystal may not be completely dissolved in the electrolyte solution in the decoloring step. Thus, when the crystal cannot be completely dissolved in the electrolytic solution, the crystal remains on the transparent electrode as debris (black spots).

  In view of such circumstances, in the process of coloring in the electrochromic display device, for example, by applying a very small current to the electrolyte for a long time, the voltage of the electrolyte is in a low negative voltage state. A method of developing colors as described above is also conceivable. However, when a very small current is passed through the electrolyte in this way, the voltage of the electrochromic display device is set to the color development threshold voltage (the minimum voltage value that needs to be applied in order to cause the electrochromic display device to develop color). There is a problem that the color does not exceed and the color does not develop even when the current is passed.

  The present invention has been made in view of the above circumstances, and in an electrochromic display device, it is possible to appropriately perform a coloring operation, and crystals that deposit on the transparent electrode grow rapidly during the coloring process. It is an object of the present invention to provide an electrochromic display device that does not.

In order to achieve the above object, an electrochromic display device according to a first aspect of the present invention includes an electrolytic solution and an electrode for injecting electric charge into the electrolytic solution, and the electrode is formed by an oxidation-reduction reaction. A display means having at least one display section that develops color when electric charge is injected into the electrolyte solution via a plurality of current pulses connected to the electrodes of the display section and intermittently outputting a constant current At least one constant current applying means for injecting the electric charge into the electrolyte by applying the plurality of current pulses to the electrodes of the display section, and the display section connected to the constant current applying means comprising a voltage detection means for detecting the voltage value of the voltage generated in the electrode, wherein the pulse width of each current pulse in the constant current applying means, is set to a constant value, put on the constant current applying means The time interval for intermittently outputting each current pulse is the voltage value of the electrode of the display unit detected by the voltage detection unit from the time when the application of one current pulse to the electrode of the display unit is completed. There characterized Rukoto is set to a time to reach a predetermined reference value.

In order to achieve the above object, a display driving apparatus according to a second aspect of the present invention includes an electrolytic solution and an electrode for injecting electric charge into the electrolytic solution. A display driving device for performing display driving of a display means provided with at least one display portion that develops color when electric charge is injected into the electrolytic solution, and is connected to an electrode of the display portion and intermittently supplies a constant current. At least one constant current applying means for injecting the electric charge into the electrolytic solution by outputting a plurality of current pulses to be output to the electrode and applying the plurality of current pulses to the electrodes of the display unit; and the constant current applying means Voltage detecting means for detecting a voltage value generated at the electrode of the display unit connected to the display, and the time interval for intermittently outputting the current pulses in the constant current applying means is one current. Said table of pulses From the time when applied to the part of the electrode is completed, the voltage value of the display portion of the electrode detected by said voltage detecting means and said Rukoto is set to a time to reach a predetermined reference value.

According to the present invention, in an electrochromic display device that develops color by injecting electric charge into the electrolyte of the display unit, a constant current is intermittently applied to the electrode of the display unit as a current pulse several times during the color development step. By injecting electric charge into the electrolytic solution by applying, the crystal deposited on the electrode does not grow rapidly , and the time interval for applying the current pulse can be changed after the application of one current pulse. By setting the time until the voltage value of the electrode voltage reaches a predetermined reference value, the time required to supply the amount of charge necessary for color development is fixed when the time interval for applying the current pulse is constant. In comparison, an electrochromic display device that is relatively short can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing a configuration of an electrochromic display device to which the display driving device according to the first embodiment of the present invention is applied. FIG. 2 is a diagram illustrating an arrangement example of display segments of the display panel.

  The electrochromic display device 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 first embodiment, as shown in FIG. 1, the display panel 10 has a plurality of display segments, and a constant current is applied to each display segment from the constant current application 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. is doing.

  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 the electrolyte solution 10-13 is filled between the electrodes 10-11 and 10-12. 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. Further, not only metals but also organic substances such as viologen compounds can be used. 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 is for setting the value of the current applied to each display segment from the constant current application circuit 20, and the voltage applied to each display segment by the applied current exceeds the coloring threshold voltage, This is a memory for storing the value of the area of each display segment or the current value designation data necessary for causing appropriate color development corresponding to the area of each display segment corresponding to each display segment. 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 coloring pulse generator 20-1 is configured by a sequential logic circuit. As shown in FIG. 4, the coloring pulse generator 20-1 includes a pulse width register 20-11, a current value register 20-12, a DA converter 20-13, a down counter 20-14, and an analog switch 20-. 15.

  The pulse width register 20-11 receives, from the system interface 40, pulse width designation data for designating a pulse width of a coloring pulse (current pulse) described later, and holds the data.

  The current value register 20-12 receives current value designation data corresponding to each display segment from the segment profile memory 30, and holds the data. The DA converter 20-13 converts the current value designation data held in the current value register 20-12 into an analog voltage signal.

  The down counter 20-14 receives a START pulse from the system interface 40 at the time of color development, reads the value held in the pulse width register, and counts down this value every predetermined time, and sends an ON or OFF signal to the analog switch 20-15. Output to. That is, the down counter 20-14 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 20-15 is connected to the DA converter 20-13 and the negative power source -V, and is turned on when receiving an ON signal from the down counter 20-14, and the output of the DA converter 20-13 is supplied to the constant current driver 20. -3 and the voltage value -V is input to the constant current driver 20-3 when the OFF signal is received.

  With such a configuration, the analog switch 20-15 is turned on only while the down counter 20-14 is counting, so that the voltage value and pulse width designation data obtained by the DA converter 20-13 are designated as a result. A color-development pulse having a predetermined pulse width is input to the constant current driver 20-3. When the down counter 20-14 finishes counting, the analog switch 20-15 is turned OFF, and the voltage value -V is input to the constant current driver 20-3.

  FIG. 4 shows the configuration of the coloring pulse generator 20-1, but the decoloring pulse generator 20-2 can also be realized with a circuit configuration substantially similar to that of the coloring pulse generator 20-1. However, in the decoloring pulse generator 20-2, the power source connected to the analog switch is not a negative power source but a positive power source + V. Further, 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. The voltage at the output terminal of the constant current driver 20-3 is detected by the voltage detection circuit 20-4. The voltage detected by the voltage detection circuit 20-4 at the time of decoloring is a voltage generated according to the current flowing by the decoloring pulse and the load (resistance of the display segment, wiring resistance, etc.) connected to the output terminal. . A CPU (not shown) determines whether or not the voltage value detected by the voltage detection circuit 20-4 exceeds a predetermined reference value Vb. Further, for example, the voltage value detected from the output signal of the voltage detection circuit 20-4 is binarized depending on whether or not it exceeds a predetermined reference value Vb, and this binarized signal is illustrated via the system interface 40. It may be input to a CPU that does not. Here, the reference value Vb is set for each display segment.

  As shown in FIG. 5, since the positive direction constant current applying means constitutes a constant current driver, the amount of current applied to the display segment 10-1 regardless of the voltage change or the like in the display segment 10-1. 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 positive 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 timing chart showing an outline of changes in the current applied to the display segment from the constant current application circuit 20 and the voltage generated by this current at the time of coloring and erasing. FIG. 8 shows the first embodiment. 6 is a timing chart showing the timing of the current applied from the constant current application circuit 20 to the display segment when the electrochromic display device according to the embodiment is colored. Here, in FIG. 7, the upper side of the drawing is the positive direction, and the lower side of the drawing is the negative direction. It should be noted that the current and voltage changes shown in FIG. 7 are an outline. In the first embodiment, during color development, as shown in the timing chart shown in FIG. Apply intermittently multiple times in pulses. Here, the pulsed current applied to the display segment during color development is referred to as a color development pulse (current pulse). This coloring pulse is applied a plurality of times at regular intervals, for example.

As shown in FIGS. 7 and 8, the pulse width designated by the pulse width designation data and the negative constant current designated by the current value designation data stored in the segment profile memory 30 (from the display segment 10-1 to the constant current). When a plurality of coloring pulses having a current in the direction of the driver 20-3 are applied, negative charges corresponding to the applied current × pulse width × number of pulses are injected into the display segment, and coloring occurs. Here, as described above, the voltage value applied to the display segment by the color pulse current exceeds the color threshold voltage, and corresponds to the value of the display segment area or the area of the display segment. Therefore, since it has a value necessary for producing an appropriate color, it is possible to produce an appropriate color. In addition, the amount of charge necessary to properly color the display segment is about 30 mC / cm ² in the case of an electrolytic solution containing Ag or Bi as the main raw material. In the first embodiment, the amount of charge is applied to the display segment. By changing the number of color pulses to be generated, the amount of charge injected into the display segment is accurately controlled, and the display segment is colored not only in a completely colored state and a completely decolored state, but also in an intermediate state. You can also. Thereby, gray scale display is possible. 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, since the resistance value of the display segment increases and the voltage rises when erasing progresses to some extent, a reference value voltage Vb lower than the limit voltage is set. The voltage detection circuit 20-4 detects when the resistance value of the display segment changes and the voltage exceeds Vb (when t1 in FIG. 7 has elapsed).

  Then, since the display segment has not yet been completely erased at the time when t1 has elapsed, additional decoloration is performed only for a predetermined time t2 after t1.

  As described above, in the first embodiment, as shown in FIG. 8, the current applied to the electrochromic display device at the time of color development is applied as a plurality of pulses (color development pulses), and the current value necessary for color development. Is intermittently applied to each display segment of the electrochromic display device. As a result, the average value of the current applied at the time of color development can be made very small while appropriately performing the color development operation, so that a phenomenon in which crystals precipitated on the transparent electrode grow rapidly occurs. Can be prevented.

  Specifically, as shown in FIG. 8, a coloring pulse is applied for 10 ms, for example, and then waits for an interval of 90 ms, for example. In the first embodiment, the interval between the application of the coloring pulses is constant. In order to apply the coloring pulse for 10 ms in this way, the following series of operations are performed in the coloring pulse generator 20-1. First, the pulse width register 20-11 receives from the system interface 40 pulse width designation data for designating the pulse width (10 ms in this case) of the coloring pulse, and holds the data. The down counter 20-14 receives a START pulse from the system interface 40 at the time of color development, reads out the pulse width designation data held in the pulse width register 20-11, and counts down this value every predetermined time. , ON or OFF signal is output to the analog switch 20-15. Thereafter, the analog switch 20-15 is turned on when receiving the ON signal from the down counter 20-14, and the pulse width designated by the voltage value obtained by the DA converter 20-13 and the pulse width designation data. A coloring pulse having (here 10 ms) is input to the constant current driver 20-3. Such application of the coloring pulse is repeated at 90 ms intervals.

  Thereafter, the application of the coloring pulse is continued in the above-described application period until the total amount of charges injected into the electrochromic display device by the applied coloring pulse reaches the amount of charge necessary for the coloring of the electrochromic display device. As described above, by intermittently applying the color-development pulse to the electrochromic display device, the current applied at the time of color-development can be made to be a very small current.

  As described above, according to the first embodiment, the electrochromic display device in which the crystals deposited on the transparent electrode do not grow rapidly while appropriately performing the coloring operation during the coloring process. Can be provided.

  That is, according to the electrochromic display device according to the first embodiment, it is possible to solve the above-described problems that occur when a large current is passed during the color development step. Specifically, the terminal voltage of the electrochromic display device is increased to the negative side by intermittently applying the coloration pulse to the display segment of the electrochromic display device during the color development step. Thus, it is possible to prevent a phenomenon in which crystals that are deposited on the transparent electrode grow rapidly.

  Therefore, according to the electrochromic display device according to the first embodiment, it is possible to prevent a phenomenon in which the crystal cannot be completely dissolved in the electrolytic solution in the decoloring step, and the crystal is dissolved in the electrolytic solution. It is possible to prevent the crystals from remaining on the transparent electrode as scum (black crumbs) due to the fact that they cannot be exhausted.

  In the first embodiment, the waiting time from the application of the coloring current for 10 ms to the application of the coloring pulse again is 90 ms. However, the waiting time is not limited to 90 ms, and may be a time when the voltage of the electrochromic display device is sufficiently increased when the coloring pulse is not applied. The time for applying the coloring pulse is 10 ms for convenience of explanation, but it is needless to say that the time is not limited to 10 ms.

[Second Embodiment]
Hereinafter, an electrochromic display device according to a second embodiment of the present invention will be described with reference to the drawings.

  FIG. 9 is a timing chart showing a current applied from the constant current application circuit 20 to the display segment and a change in voltage generated by the current when the electrochromic display device according to the second embodiment is colored. In the figure, the upper side of the drawing is the positive direction and the lower side of the drawing is the negative direction.

  In the electrochromic display device according to the first embodiment, the color pulse application interval is fixed. However, in the electrochromic display device according to the second embodiment, the color pulse application interval is set to the electrochromic display device. The difference is that it can be varied according to the voltage value generated in the display segment.

That is, in the second embodiment, as shown in FIG. 9A, the voltage of the display segment during the period when the coloring pulse is not applied is detected and observed by the voltage detection circuit 20-4 (see FIG. 1). . Here, the voltage of the display segment detected by the voltage detection circuit 20-4 is a voltage based on the electromotive force generated in the display segment when the current due to the coloring pulse is applied. That is, in an electrochromic display device, it is known that when a negative direction current is applied to a display segment during color development, a negative electromotive force is generated in the display segment, and this negative electromotive force is about −25 mV. is there. A CPU (not shown) determines whether or not the voltage value detected by the voltage detection circuit 20-4 exceeds a predetermined reference value _VA . The reference value V _A is set to a value corresponding to the negative electromotive force of the display segment, and is set to about −30 mV, for example.

When the CPU (not shown) determines that the voltage value of the display segment detected by the voltage detection circuit 20-4 is equal to or higher than the reference value _VA after the application of the coloring current (FIG. 9B). (See FIG. 9 (a)). This operation is repeated until the total amount of charges injected into the display segment of the electrochromic display device by the applied coloring pulse reaches the amount of charge necessary for coloring the display segment. At this time, each time a color pulse is applied, the amount of charge injected into the display segment increases, and the value of the electromotive force generated in the display segment gradually increases in the negative direction. Since the time until the reference value _VA is reached is gradually increased, as shown in FIG. 9A, the color pulse application interval is gradually increased.

  As described above, according to the present embodiment, in addition to the same effects as the electrochromic display device according to the first embodiment, an electrochromic display device having the following effects can be provided. .

That is, in the electrochromic display device according to the first embodiment, the interval at which the color pulse is applied is constant, so that depending on the color pulse application interval, the voltage applied to the display segment by repeated application of the color pulse. Gradually increases in the negative direction and exceeds the limit voltage at which the display segment is not destroyed. According to the electrochromic display device according to the second embodiment, as shown in FIG. The voltage of the display segment after applying the coloring pulse is observed, and the coloring pulse is applied again after the voltage of the electrochromic display device exceeds the reference value _VA as shown in FIG. 9B. This prevents the voltage applied to the display segment from increasing in the negative direction, as shown in FIG. You can. Further, as shown in FIG. 9 (a), the interval at which the coloring pulse is applied is controlled so that the interval is initially short and the interval is gradually increased. Therefore, the interval at which the coloring pulse is applied as in the first embodiment. Compared with the case where it is constant, the time required to supply the charge amount necessary for color development can be made relatively short.

  Although the present invention has been described based on the 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. For example, although each of the above-described embodiments has been described with respect to a segment type display panel, the method of each of the above-described embodiments can be applied to a dot matrix type display panel. However, in the case of the dot matrix method, the area of each display unit is the same, so the segment profile memory 30 is not necessarily required. In this case, the reference value Vb may be a common value for each display segment.

  Furthermore, the embodiments described above include inventions at various stages, 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 a first 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 timing chart which shows the change of the electric current applied to a display segment from a constant current application circuit at the time of color development and erasing, and the voltage which generate | occur | produces with this electric current. 6 is a timing chart showing a change in current applied from the constant current application circuit to the display segment during color development of the electrochromic display device according to the first embodiment of the present invention. (A) is a timing chart which shows the change of the electric current applied to a display segment from a constant current application circuit at the time of color development of the electrochromic display device concerning a 2nd embodiment of the present invention. (B) is a timing chart showing a change in voltage generated by the current.

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 20-11 ... Pulse width register 20-12 ... Current value register 20-13 ... DA converter 20 -14 ... down counter 20-15 ... 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 (5)

An electrolyte and an electrode for injecting electric charge into the electrolyte, and at least one display portion that is colored by injecting electric charge into the electrolyte through the electrode by an oxidation-reduction reaction is disposed Display means,
A current pulse that is connected to the electrode of the display unit and outputs a constant current intermittently is output a plurality of times, and the plurality of current pulses are applied to the electrode of the display unit to inject the charge into the electrolyte solution. At least one constant current applying means;
Voltage detecting means for detecting a voltage value of a voltage generated at the electrode of the display unit connected to the constant current applying means;
Equipped with,
The pulse width of each current pulse in the constant current applying means is set to a constant value,
The time interval for intermittently outputting each of the current pulses in the constant current applying means is the display detected by the voltage detecting means from the point in time when the application of one current pulse to the electrodes of the display section is completed. electrochromic display device voltage parts of the electrode, wherein Rukoto is set to a time to reach a predetermined reference value. Claims wherein the current value of the current pulses applied to the electrodes of the display unit from the constant current applying means, and further comprising said Rukoto the current value setting means for setting a value proportional to the area of the electrodes of the display unit Item 2. The electrochromic display device according to Item 1. An electrolyte and an electrode for injecting electric charge into the electrolyte, and at least one display portion that is colored by injecting electric charge into the electrolyte through the electrode by an oxidation-reduction reaction is disposed A display driving device for performing display driving of the displayed display means,
A current pulse that is connected to the electrode of the display unit and outputs a constant current intermittently is output a plurality of times, and the plurality of current pulses are applied to the electrode of the display unit to inject the charge into the electrolyte solution. At least one constant current applying means;
Voltage detection means for detecting a voltage value generated at the electrode of the display unit connected to the constant current application means;
Comprising
The time interval for intermittently outputting each of the current pulses in the constant current applying means is the display detected by the voltage detecting means from the point in time when the application of one current pulse to the electrodes of the display section is completed. A display driving device characterized in that the time is set until the voltage value of the electrode of the part reaches a predetermined reference value . 4. The display driving device according to claim 3, wherein a pulse width of each of the current pulses in the constant current applying unit is set to a constant value . The current value setting means for setting the current value of the current pulse applied to the electrode of the display unit from the constant current applying unit to a value proportional to the area of the electrode of the display unit. 4. The display driving device according to 3 .

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