JPS641755B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a timepiece having an electrochromic (hereinafter abbreviated as EC) display section, which is provided with a structure for erasing the memory contents of the EC display section when the battery is removed. Regarding drive circuits.

In recent years, methods have been developed that use EC display materials, which have advantages such as a wide viewing angle and good coloring properties, in the display section of electronic watches. However, EC display materials have the characteristic that once a voltage is applied and the display develops a color, it has a memory effect for a certain period of time even when the voltage is turned off, so the display does not disappear, and a reverse voltage must be applied to erase the color. Because of this feature, even if the user removes the battery, the current time will remain displayed on the EC display due to its memory function, and when the battery is inserted again, the clock circuit inside the IC will continue to display the current time. The measured time does not necessarily match the displayed time depending on the memory contents of the EC display section. If the time is displayed in this state, there is a risk that an imbalance will occur in the charges accumulated in each segment of the EC display section, and the display will not be written or erased correctly, making it impossible to display the time correctly thereafter. It was hot. This has been a major problem with the implementation of using EC display materials in the display section of watches. In contrast, conventionally, as described in Japanese Patent Application Laid-Open No. 52-73688, it has been proposed to detect the insertion of a battery and at this time supply a signal to the display section to once erase the display. However, even with this technology, the above problem has not been solved satisfactorily. In other words, if you leave the display for a long time without erasing the display after removing the battery, the segments that are displayed may
Depending on the type of EC substance, chemical changes may occur and the eraser cannot be completely erased even if a subsequent eraser pulse is supplied, or the charge may gradually discharge from the displaying segment by the time the battery is inserted. If you supply a new erasing pulse here,
Depending on the type of EC material, erasing charges may remain, making it impossible to display a sufficient display even when a writing pulse is supplied next time. Furthermore, in the conventional device, there was the inconvenience of having to operate an external operating member each time to erase the display when replacing the battery.

Therefore, in order to solve this conventional problem, the present invention erases the memory contents of the EC display section when the battery is removed from the watch to clear the display, and when the battery is reinserted, the time can be displayed normally. This is how it was done.

A detailed explanation will be given below based on the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. The oscillator 2 generates a time reference signal, and the frequency divider 4 is a circuit that divides the signal from the oscillator 2 to a required frequency. The clock circuit 6 is a circuit that receives the output signal from the frequency divider 4 and measures time. The time signal clocked by the clock circuit 6 is converted by the decoder 8 into a signal for displaying segments on the EC display section 10, and is input to the drive circuit 12.

In this embodiment, a signal that outputs a pulse every 10 seconds is sent from the clock circuit 6 to the AND gates 14 and 16.
input to one of the inputs of and gates 14, 16
The output line 19 of the main power detection circuit 18 is connected to the other input. Main power detection circuit 18
detects the voltage of the power supply battery 20 for operating the clock, and when the voltage reaches 0, the output line 19
This circuit outputs an L level signal to the output line 19, and outputs an H level signal to the output line 19 when the voltage exceeds a certain value. And main power detection circuit 1
The output line 19 of 8 is also connected to a one-shot circuit 24 via an inverter 22. When the one-shot circuit 24 receives an H level signal, it outputs one pulse having the same pulse width as the pulse input from the clock circuit 6 to the AND gate 14.
This is a circuit that outputs to.

On the other hand, the output of the AND gate 16 is connected to a write signal circuit 28. The write signal circuit 28 receives the signal from the AND gate 16 and writes the drive circuit 1
2 is a circuit that causes the EC display section 10 to develop color. Its configuration, for example, as shown in Japanese Patent Laid-Open No. 53-130996, changes in the input signal are delayed by the erasing pulse width, and the delayed signal is It consists of a one-shot circuit that generates a pulse signal in response to changes.
Further, the output of the AND gate 14 is inputted to one of the inputs of the OR gate 26. The output of the one-shot circuit 24 is input to the other input of the OR gate 26. The output of the OR gate 26 is connected to an erase signal circuit 30, and the erase signal circuit 30
The EC display section 10 receives a signal from the OR gate 26.
The drive circuit 12 sends an erasing pulse to erase the color of the
As shown in the above-mentioned Japanese Patent Laid-Open No. 53-130996, this circuit is composed of a one-shot circuit that generates a pulse signal in response to a change in an input signal. The drive circuit 12 is a circuit that amplifies the write pulse from the write signal circuit 28 and the erase pulse from the erase signal circuit 30 in response to the output signal from the decoder to a signal that causes the EC display section 10 to erase and write. It is.

On the other hand, the power supply battery 20 is connected to the auxiliary power supply 32 and the output line 3.
3 to each circuit. Auxiliary power supply 3
2 is the power supply battery 2 when the power supply battery 20 is removed.
This circuit supplies voltage to each circuit via the output line 33 instead of 0.

The operation of this circuit will be explained below.

Normally, pulses every 10 seconds from the clock circuit 6 are inputted to the write signal circuit 28 via the AND gate 16, and are also inputted to the erase signal circuit 30 via the AND gate 14 and the OR gate 26. The write signal circuit 28 outputs a write pulse, and the erase signal circuit 30 outputs an erase pulse. The writing pulse and erasing pulse are input to the EC display section 10 via the drive circuit 12, and time is written and erased on the EC display section 10 every 10 seconds.

When the power supply battery 20 is taken out from the storage section, the voltage becomes 0V, and power is supplied to each circuit from the auxiliary power supply 32 via the output line 33. When the main power supply detection circuit 18 detects that the power supply battery 20 has become 0V, it outputs an L level signal to the AND gates 14 and 16. As a result, the AND gates 14 and 16 are closed, and the pulses every 0 seconds from the clock circuit 6 are transmitted to the write signal circuit 28 and the erase signal circuit 3.
No longer enter 0. At the same time, inverter 2
2, the H level signal is sent to the one shot circuit 2.
4 to the erase signal circuit 30 via the OR gate 26
One pulse is input to . As a result, the erasing signal circuit 30 inputs one erasing pulse to the EC display section 10 via the drive circuit 12, erases the memory contents of the EC display section 10, and clears the display.

When the power battery 20 enters the storage section again, the main power detection circuit 18 detects the voltage of the power battery 20 and outputs an H level signal to the AND gates 14 and 16. As a result, the AND gates 14 and 16 are opened, and pulses every 10 seconds from the timer circuit 6 are input to the write signal circuit 28 and the erase signal circuit 30. Then, the time counted by the clock circuit 6 is again written and erased on the EC display section 10 every 10 seconds.

In this way, each time you take out the power battery 32, the EC
Since all the memory contents of the display section 10 are erased, the EC display section 10 will display the normal time when the power battery 32 is inserted thereafter.

FIG. 2 shows the main power detection circuit 18 in FIG.
This is an example of an auxiliary power source 32.

The main power supply detection circuit 18 includes a high resistance 40 connected in parallel to the power supply battery 20 and inverters 42 and 44 connected in parallel to the resistance 40.
The threshold voltages of the inverters 42 and 44 are set below the operating voltage of the watch.
The output line 19 of is connected to a one-shot circuit 24 via AND gates 14 and 16 or an inverter 22. The auxiliary power supply 32 is composed of an electrolytic capacitor 46 with a small voltage drop connected in parallel to the power supply battery 20 and a diode 48 inserted between the electrolytic capacitor 46 and the power supply battery 20. The electrolytic capacitor 46 is connected to each circuit via the output line 33.

With the above configuration, when the power source battery 20 is connected, the electrolytic capacitor 46 is charged from the power source battery 20 via the diode 48 . Also, while the power battery 20 is connected, the voltage of the power battery 20 is applied to the high resistance 40, so the inverter 4
The signal on output line 19 of No. 4 becomes H level. As a result, an H level signal is applied to one of the inputs of AND gates 14 and 16. When the power supply battery 20 is removed, each circuit continues to operate for a certain period of time due to the charge stored in the electrolytic capacitor 46. On the other hand, when the power supply battery 20 is removed, the voltage applied to the high resistance 40 becomes 0, and the signal on the output line 19 of the inverter 44 becomes L level. Then, the AND gates 14 and 16 are closed, and an H level signal is input to the one shot circuit 24 via the inverter 22.

In this way, if an electrolytic capacitor 46 as shown in FIG. 2 is used as an auxiliary power source, there is no need to replace the auxiliary power source, and the configuration becomes simple.

In this embodiment, an electrolytic capacitor is used as an auxiliary power source, but it is also more effective to use a photovoltaic cell, a rechargeable battery, or the like. In addition, by using relatively large-capacity photovoltaic cells and secondary batteries as auxiliary power sources, the clock circuit is operated between the time the power source battery is removed and the time it is reinserted, so that there is no need to adjust the time when the battery is inserted. This is also possible.

As described above, according to the present invention, the erasing pulse is supplied to the time display section immediately when the power supply battery is removed, so that it can be left for a long period of time after the battery is removed, as in the conventional case. The memory effect of EC substances does not continue for a long time, and during this time
The EC substance may undergo a chemical change and may no longer be completely erased when the erasing pulse is supplied, or the erase charge may remain due to spontaneous discharge of the write charge, causing the display to become faint when writing next time. It disappears. Therefore, it is possible to provide an EC display clock that can continue to display the normal time even if the battery is replaced as in the past. Furthermore, since the present invention detects the battery removal operation using voltage detection and generates the erasing pulse, there is no need for an external operation to generate the erasing pulse when replacing the battery, making it easier to use. get well.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention;
FIG. 2 is a diagram showing an embodiment of the main power supply detection circuit and auxiliary power supply in FIG. 1. 10... EC display unit, 14, 16... AND gate, 18... Main power supply detection circuit, 20... Power supply battery, 24... One shot circuit, 26... OR gate, 32... Auxiliary power supply.

Claims (1)

[Claims] 1. A time signal forming circuit that measures a reference signal to form a time signal; and an electrochromic display section, which displays a time corresponding to the time signal according to an erasing pulse and a writing pulse. and a one-shot circuit that outputs a pulse signal in response to a constant periodic signal output from the time signal forming circuit, and an erasing signal that supplies the pulse signal to the time display section as an erasing pulse. a one-shot circuit that delays a constant periodic signal output from the time signal forming circuit by at least the erasing pulse width and outputs a pulse signal in response to the delayed signal, and outputs a pulse signal in response to the delayed signal; A main power supply detection circuit that outputs a detection signal when the drive voltage from the battery drops below a predetermined value in a timepiece that includes a write signal circuit that supplies pulses to the time display section and a battery that supplies drive voltage. a pulse blocking circuit that blocks the output of the constant periodic signal in response to the output of the detection signal; and a pulse blocking circuit that outputs a trigger signal in response to the output of the detection signal, and erases the signal from the erasure signal circuit to the time display section. a display erasing circuit that supplies pulses for the display erasing, and supplying a drive voltage to at least the time signal forming circuit, the time display section, the erasing signal circuit, the main power detection circuit, the pulse blocking circuit, and the display erasing circuit due to the decrease in the drive voltage; A drive circuit for an electrochromic display section, characterized in that it is provided with an auxiliary power source. 2. An electrochromic display unit as set forth in claim 1, wherein the auxiliary power source is comprised of a condenser capable of charging the output from the battery and a diode for preventing backflow to the battery. drive circuit.