Drive unit, electronic timepiece, drive method, and program

Abstract

To provide a drive unit, an electronic timepiece, a drive method, and a program capable of appropriately displaying an image.SOLUTION: A drive unit comprises a control section 20 for controlling a liquid crystal display section 11, and the control section is configured so as to be capable of executing polarity inversion processing for inverting the polarity of voltage applied to a liquid crystal 14a in the liquid crystal display section at a fixed period, writing processing for displaying an image on the liquid crystal display section according to a writing request of an image, and determination processing for determining whether writing processing is first writing processing after inversion of polarity before the writing processing, and delays execution of writing processing until a preset writing prohibition period passes when determining that writing processing is first writing processing after inversion of polarity in determination processing, and executes writing processing without waiting for lapse of a writing prohibition period when determining that writing processing is not first writing processing after inversion of polarity in determination processing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drive unit, an electronic timepiece, a drive method, and a program. [Background technology]

[0002] To prevent deterioration of the liquid crystal, a liquid crystal display device displays images while performing a polarity inversion process in which the polarity of the voltage applied to the liquid crystal is inverted at regular intervals. In a liquid crystal display device, if the polarity inversion of the voltage in the polarity inversion process overlaps with the image writing process, the image may not be displayed properly. For this reason, liquid crystal display devices are designed to prohibit the writing process for a certain period of time after the polarity inversion of the voltage applied to the liquid crystal.

[0003] Patent Document 1 discloses a technology relating to an electronic watch equipped with a CPU that reverses the polarity of the voltage applied to the display unit at a time equal to or shorter than a reference reversal time at the reversal timing of a fixed polarity reversal cycle, and outputs image data to a display drive circuit at an image update timing that is synchronized with the polarity reversal cycle and has the same period as a reference cycle that is an integer multiple of the polarity reversal cycle, and that is later than the reference cycle by a reference adjustment time that is shorter than the reference cycle and longer than the reference reversal time.With this configuration, the electronic watch in Patent Document 1 is said to be able to smoothly update the image data displayed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6866817 Summary of the Invention [Problem to be solved by the invention]

[0005] There is room for further improvement in electronic watches in terms of displaying images properly. For example, if the timing of the writing process is set so that it does not coincide with the timing of the voltage polarity reversal, as in the electronic watch of Patent Document 1, the real-time nature of the displayed image may be impaired. Furthermore, in a method like the electronic watch of Patent Document 1, in which the image transmission period is determined relative to the polarity reversal cycle and the timing is carefully measured and controlled, a counter that operates at a high clock frequency to measure the transmission timing is required, and this counter must be constantly running in synchronization with the polarity reversal. As a result, such electronic watches may consume a lot of power.

[0006] An object of the present invention is to provide a drive device, an electronic timepiece, a drive method, and a program that can reduce power consumption and display images appropriately. [Means for solving the problem]

[0007] The driving device of the present invention includes a control unit for controlling a liquid crystal display unit, and the control unit is configured to be able to execute a polarity reversal process for reversing the polarity of a voltage applied to the liquid crystal of the liquid crystal display unit at a constant cycle, a write process for displaying an image on the liquid crystal display unit in response to a request to write the image, and a judgment process for judging, before the write process, whether the write process is the first write process after the polarity reversal.If the judgment process determines that the write process is the first write process after the polarity reversal, the execution of the write process is delayed until a predetermined write prohibition period has elapsed, and if the judgment process determines that the write process is not the first write process after the polarity reversal, the control unit executes the write process without waiting for the write prohibition period to elapse.

[0008] The electronic watch of the present invention comprises a timing unit that measures the current time, a liquid crystal display unit that displays an image representing the current time measured by the timing unit, and a control unit that controls the liquid crystal display unit, wherein the control unit is configured to be able to execute a polarity inversion process that inverts the polarity of the voltage applied to the liquid crystal of the liquid crystal display unit at a regular interval, a write process that displays an image on the liquid crystal display unit in response to an image write request, and a judgment process that determines before the write process whether the write process is the first write process after the polarity inversion, and if the judgment process determines that the write process is the first write process after the polarity inversion, the execution of the write process is delayed until a predetermined write prohibition period has elapsed, and if the judgment process determines that the write process is not the first write process after the polarity inversion, the write process is executed without waiting for the write prohibition period to elapse.

[0009] The driving method of the present invention comprises a polarity inversion step of inverting the polarity of a voltage applied to the liquid crystal of a liquid crystal display unit at a constant cycle; a writing step of displaying an image on the liquid crystal display unit in response to a request to write the image; and a determination step of determining, before the writing step, whether the writing step is the first writing step after the polarity inversion, wherein, if it is determined in the determination step that the writing step is the first writing step after the polarity inversion, execution of the writing step is delayed until a predetermined write inhibition period has elapsed, and if it is determined in the determination step that the writing step is not the first writing step after the polarity inversion, the writing step is executed without waiting for the write inhibition period to elapse.

[0010] The program of the present invention causes a computer to execute a polarity reversal process that reverses the polarity of a voltage applied to the liquid crystal of a liquid crystal display unit at a regular interval; a write process that displays an image on the liquid crystal display unit in response to a write request for the image; and a determination process that determines, before the write process, whether the write process is the first write process after the polarity reversal. If the determination process determines that the write process is the first write process after the polarity reversal, the program delays execution of the write process until a preset write prohibition period has elapsed, and if the determination process determines that the write process is not the first write process after the polarity reversal, the program executes the write process without waiting for the write prohibition period to elapse and without delay. [Effects of the Invention]

[0011] The drive device, electronic timepiece, drive method, and program according to the present invention have the effect of being able to properly display images. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of an electronic timepiece according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of a liquid crystal display device in an electronic timepiece according to an embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of a liquid crystal display device in an electronic timepiece according to an embodiment. [Figure 4] FIG. 4 is a timing chart showing an example of the timing of the writing process of the drive device according to the embodiment. [Figure 5] FIG. 5 is a flowchart illustrating an example of a driving method according to the embodiment. [Figure 6] FIG. 6 is a flowchart illustrating an example of a driving method according to the embodiment. [Figure 7] FIG. 7 is a flowchart illustrating an example of a driving method according to the embodiment. [Figure 8] FIG. 8 is a timing chart showing the operation timing of the driving device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Below, a driving device, an electronic timepiece, a driving method, and a program according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that would be easily conceivable to a person skilled in the art or that are substantially the same.

[0014] [Embodiment] An embodiment will be described with reference to Fig. 1 to Fig. 8. The embodiment relates to a drive device, an electronic timepiece, a drive method, and a program. Fig. 1 is a diagram showing an example of the configuration of an electronic timepiece according to an embodiment, Fig. 2 is a diagram showing an example of the configuration of a liquid crystal display device in an electronic timepiece according to an embodiment, Fig. 3 is a diagram showing an example of the configuration of a liquid crystal display device in an electronic timepiece according to an embodiment, Fig. 4 is a timing chart showing an example of the timing of a write process of a drive device according to an embodiment, Fig. 5 is a flowchart showing an example of a drive method according to an embodiment, Fig. 6 is a flowchart showing an example of a drive method according to an embodiment, Fig. 7 is a flowchart showing an example of a drive method according to an embodiment, and Fig. 8 is a timing chart showing the operation timing of a drive device according to an embodiment.

[0015] The electronic timepiece 100 according to the embodiment is a wristwatch worn on the user's wrist. The drive device according to the embodiment is a device that drives and controls the liquid crystal display unit 11 of the liquid crystal display device 10 in the electronic timepiece 100. As shown in FIG. 1 , the electronic timepiece 100 according to the embodiment includes the liquid crystal display device 10, a control unit 20, and a timing unit 30.

[0016] As shown in Fig. 2, the liquid crystal display device 10 includes a liquid crystal display unit 11 and a display drive circuit 101. The liquid crystal display unit 11 includes a plurality of pixels 11a. In the liquid crystal display unit 11, the plurality of pixels 11a are arranged vertically and horizontally in a matrix. As shown in Fig. 3, the liquid crystal display unit 11 of this embodiment is an MIP (memory-in-pixel) liquid crystal in which each of the plurality of pixels 11a arranged in a matrix includes a memory element 12 that stores display data for that pixel 11a.

[0017] The display drive circuit 101 is a component that outputs drive signals for driving the liquid crystal display unit 11 to the liquid crystal display unit 11 based on control signals from the control unit 20, and causes the liquid crystal display unit 11 to display the time and various functions. The display drive circuit 101 is configured to include a data driver 101a, a gate driver 101b, and a VCOM driver 101c.

[0018] The data driver 101a is a component that outputs a data signal of display data to the data bus line 15a based on a control signal from the control unit 20. The gate driver 101b is a component that outputs a scanning signal to the gate bus line 15b based on a control signal from the control unit 20. The VCOM (common electrode voltage) driver 101c is a component that outputs a voltage (common electrode voltage: VCOM) to be applied to the common electrode of the pixel 11a (described later) based on a control signal from the control unit 20.

[0019] In this embodiment, each pixel 11a of the liquid crystal display unit 11 includes a memory element 12, a display voltage supply driver 13, and a display element 14. In each pixel 11a, the memory element 12 is a component that stores a data signal output from a data driver 101a of the display drive circuit 101 as display data, and the display voltage supply driver 13 is a component that applies a voltage corresponding to the display data stored in the memory element 12 to the liquid crystal 14a of the display element 14. Here, the display element 14 includes the liquid crystal 14a, a pixel electrode 14b, and a common electrode 14c.

[0020] The liquid crystal 14a is connected to a pixel electrode 14b and a common electrode 14c. The pixel electrode 14b is connected to a display voltage supply driver 13, and the common electrode 14c is connected to a VCOM driver 101c. In each pixel 11a, the crystal orientation of the liquid crystal 14a is controlled by the potential difference between the pixel electrode 14b and the common electrode 14c, thereby displaying an image.

[0021] The control unit 20 constitutes a driving device according to the embodiment, and controls the liquid crystal display unit 11 of the liquid crystal display device 10. As shown in FIG. 1, the control unit 20 includes a CPU (Central Processing Unit) 21, a storage unit 22, and a timer circuit 23.

[0022] The CPU 21 is a processor that performs various calculation processes and controls the overall operation of the electronic timepiece 100. The storage unit 22 is, for example, a rewritable semiconductor memory such as RAM (Random Access Memory). The storage unit 22 stores conditions and information necessary for various processes in the control unit 20, various programs and applications executed by the control unit 20, control data, etc. The timer circuit 23 is a component that, in the determination process described below, times the time (write inhibit period) for delaying the write process performed by the control unit 20 on the liquid crystal display unit 11 of the liquid crystal display device 10 if this is the first write process after the polarity of the voltage is reversed.

[0023] In the electronic watch 100 according to the embodiment, the control unit 20 is configured to be able to execute a polarity inversion process that inverts the polarity of the voltage applied to the liquid crystal 14a of the liquid crystal display unit 11 at a fixed period (polarity inversion period), a write process that displays an image on the liquid crystal display unit 11 in response to an image write request, and a judgment process that judges before the write process whether the write process is the first write process after the polarity inversion.

[0024] The polarity inversion process is a process in which the control unit 20 controls the VCOM driver 101c to invert the polarity of the voltage applied to the liquid crystal 14a included in the pixel 11a of the liquid crystal display unit 11. In the polarity inversion process of the embodiment, the time ratio between the period when the applied voltage is positive and the period when the applied voltage is negative is set to 50% (duty ratio 50%) in order to suppress deterioration of the liquid crystal 14a. For example, as shown in FIG. 4, in the polarity inversion process of the embodiment, the polarity of the voltage applied to the liquid crystal 14a is inverted every second. That is, in the polarity inversion process of the embodiment, the period (polarity inversion period) for inverting the polarity of the voltage applied to the liquid crystal 14a is set to a period of one second.

[0025] The write process is a process of displaying an image on the liquid crystal display unit 11 in response to a write request for the image. The image write request is made, for example, from the clock unit 30 to the control unit 20. In this case, the clock unit 30 makes a write request for an image representing the current time to the control unit 20, and the control unit 20 executes the write process in response to the write request, whereby the image representing the current time is displayed on the liquid crystal display unit 11.

[0026] In this embodiment, the timing of the write process within one polarity reversal cycle is not fixed. This is because, depending on the information displayed on the electronic watch, partial rewriting is often sufficient, eliminating the need for a full rewrite of the LCD screen. Furthermore, write requests are not frequent, making it more efficient to perform the write process when a write request occurs. While a write request may overlap with a polarity reversal or a write-prohibited period associated with the polarity reversal, this only occurs with the first write request after the polarity reversal. For initial write requests that occur during the polarity reversal or write-prohibited period associated with the polarity reversal, the control unit 20 processes the request so that it does not overlap with the polarity reversal or write-prohibited period associated with the polarity reversal. For other write requests, the control unit 20 immediately begins the write process. In other words, when a write request occurs, the electronic watch 100 according to this embodiment determines whether the request is the first write request after the polarity reversal. If it is the first write request, the control unit 20 performs the write process with a delay. If it is not, the control unit 20 continues the write process.

[0027] The determination process is a process for determining, before a write process within one polarity reversal period, whether the write process is the first write process after polarity reversal. If the control unit 20 determines in the determination process that the write process is the first write process after polarity reversal, it delays the execution of the write process until a preset write prohibition period has elapsed. Furthermore, if the control unit 20 determines in the determination process that the timing of the write process is not the first write process after polarity reversal, it executes the write process without waiting for the write prohibition period to elapse. This configuration makes it possible to prevent the write process from overlapping with the polarity reversal timing of the voltage applied to the liquid crystal 14a or the write prohibition period associated with polarity reversal, thereby suppressing, for example, image writing errors on the liquid crystal display unit 11.

[0028] The write inhibition period is set to start when the first write request is made after the polarity of the voltage applied to the liquid crystal 14a is reversed and to end before the next polarity reversal. The write inhibition period is set to be sufficiently shorter than one polarity reversal period of the voltage applied to the liquid crystal 14a. For example, the length of the write inhibition period is set to be equal to the write inhibition time after polarity reversal defined in the specifications of the liquid crystal display device 10.

[0029] For example, as shown in FIG. 4, among the timings T1 to T4 of the write process in response to a write request, the timings T1 and T4 of the write process correspond to the first write process after the polarity reversal of the voltage applied to the liquid crystal 14a (the polarity reversal of VCOM). In this case, the control unit 20 executes the write process at the timings T1 and T4 with a delay of the write inhibit period TS. Among the timings T1 to T4 of the write process, the timings T2 and T3 of the write process do not correspond to the first write process after the polarity reversal of the voltage applied to the liquid crystal 14a (the polarity reversal of VCOM). Therefore, the control unit 20 executes the write process at the timings T2 and T3 without waiting for the write inhibit period TS to elapse. In this embodiment, the control unit 20 executes the write process at the timings T2 and T3 without delay.

[0030] Here, it is possible that the timing for polarity reversal of the voltage in the polarity reversal process may occur during the writing process. When the writing process coincides with the timing for polarity reversal of the voltage applied to the liquid crystal 14a in the polarity reversal process, the control unit 20 of the embodiment executes the writing process without reversing the polarity of the voltage applied to the liquid crystal 14a at that timing. With this configuration, even if the timing for polarity reversal of the voltage applied to the liquid crystal 14a occurs during the writing process, it is possible to prevent the writing process and the polarity reversal of the voltage applied to the liquid crystal 14a from overlapping. Therefore, it is possible to prevent image writing errors from occurring in the liquid crystal display unit 11.

[0031] 1, the control unit 20 of this embodiment conceptually includes a VCOM counter 22a and a holding counter 22b. The VCOM counter 22a counts the number of polarity reversals of the voltage applied to the liquid crystal 14a each time the polarity of the voltage is reversed during the polarity reversal process. The holding counter 22b stores the count value of the VCOM counter 22a during the write process (i.e., the number of polarity reversals of the voltage counted by the VCOM counter 22a at that time).

[0032] In the embodiment, the control unit 20 compares the number of voltage polarity reversals counted by the VCOM counter 22a with the count value stored in the hold counter 22b in a determination process to determine whether the write process is the first write process after the polarity reversal. For example, if the number of voltage polarity reversals counted by the VCOM counter 22a differs from the count value stored in the hold counter 22b in a determination process before the write process, the control unit 20 determines that the write process is the first write process after the voltage polarity reversal. On the other hand, if the number of voltage polarity reversals counted by the VCOM counter 22a equals the count value stored in the hold counter 22b in a determination process before the write process, the control unit 20 determines that the write process is not the first write process after the voltage polarity reversal. This configuration allows the control unit 20 to determine whether the write process is the first write process after the polarity reversal of the voltage applied to the liquid crystal 14a.

[0033] In the initial state, the value of VCOM counter 22a and the value of hold counter 22b are the same. However, because VCOM counter 22a counts up with voltage polarity reversal, the values ​​of VCOM counter 22a and hold counter 22b become different after the voltage polarity reversal. When a write request is issued, control unit 20 performs a determination process to determine whether the values ​​of VCOM counter 22a and hold counter 22b are the same. If the values ​​of VCOM counter 22a and hold counter 22b are different, the control unit 20 determines that the write request is the first write request after the voltage polarity reversal. Then, control unit 20 executes the write process after suspending the write process for a period corresponding to the write inhibition period. When this write process is completed, hold counter 22b stores the value of VCOM counter 22a, so the values ​​of hold counter 22b and VCOM counter 22a become the same. When a write request occurs thereafter, control unit 20 executes a process of determining whether the value of VCOM counter 22a and the value of hold counter 22b are the same, and because the values ​​of hold counter 22b and VCOM counter 22a are the same, it determines that the write request is not an initial write request and immediately proceeds to write processing. When the write processing in response to this non-initial write request is completed, hold counter 22b may store the value of VCOM counter 22a, or the value of hold counter 22b may be left unchanged.

[0034] Because the timing of the write process within one polarity reversal cycle is not fixed, the first write request after a polarity reversal may or may not overlap with the write inhibition period associated with the polarity reversal. In either case, the write process is executed after waiting for the write inhibition period. However, write processes after the first write request after the next polarity reversal are executed immediately, so the timer that measures the write inhibition period does not operate. In other words, the electronic watch 100 of this embodiment only needs to operate the timer that measures the write inhibition period once after the polarity reversal process is executed, thereby reducing power consumption.

[0035] The clock unit 30 is a component that keeps track of the current time (internal time of the clock). The clock unit 30 outputs information related to the kept current time to the CPU 21, and the CPU 21 causes the liquid crystal display unit 11 to display an image representing the current time kept by the clock unit 30. The clock unit 30 is composed of, for example, an oscillator, an oscillation circuit, a frequency divider circuit, and a clock circuit. The clock unit 30 generates a clock signal according to the oscillation frequency of the oscillator using the oscillation circuit, and divides the clock signal using the frequency divider circuit to a signal with a frequency used by the CPU 21 and outputs it to the clock circuit. The clock circuit keeps track of the current time by counting the number of times the signal input from the frequency divider circuit is received.

[0036] Next, a driving method according to the embodiment will be described with reference to FIG.

[0037] 5, in the driving method according to the embodiment, when a request (step S1) is made to the control unit 20 to write an image to the liquid crystal display unit 11, a determination process is executed (determination step S2). In Fig. 5, by determining whether the number of times the polarity of the voltage counted by the VCOM counter 22a (the value of the VCOM counter 22a) matches the count value stored in the hold counter 22b (the value of the hold counter 22b), it is determined whether the write process to be executed after the determination process is the first write process after the polarity of the voltage applied to the liquid crystal 14a is reversed.

[0038] If the value of VCOM counter 22a and the value of the hold counter do not match in determination step S2, control unit 20 activates timer circuit 23 (determination step S2a). Timer circuit 23 measures the time until the write inhibition period expires. Then, timer circuit 23 determines whether the write inhibition period has expired (determination step S2b). Timer circuit 23 repeats the determination of determination step S2b until the write inhibition period expires, and if it determines that the write inhibition period has expired, causes control unit 20 to start the write process (write step S3). Then, when writing of the image to liquid crystal display unit 11 in the write process is completed (write step S4), the value of hold counter 22b is updated to the value of VCOM counter 22a at that time (write step S5). The determination step and write step in the driving method according to the embodiment are executed as described above.

[0039] Here, the write inhibition period is measured by a write inhibition counter that operates on a relatively high-frequency clock so that it can measure the write inhibition time after polarity reversal for the liquid crystal display device 10. Therefore, the power consumed by the operation of the write inhibition counter significantly affects the operating time of the clock. In the driving method according to the embodiment, the write inhibition counter is operated only during the first write process after the voltage polarity reversal, and is not operated unless the write process is the first after the voltage polarity reversal. Furthermore, if there is no write request, the write inhibition counter is not operated, so power is not wasted and the impact on the operating time of the clock can be reduced.

[0040] Next, with reference to FIG. 6, the operation of the driving method according to the embodiment will be described using an example in which write requests occur consecutively.

[0041] In the example of the driving method according to the embodiment shown in FIG. 5, when a write process is executed in response to the first write request generated after the voltage polarity is reversed, hold counter 22b records the value of VCOM counter 22a only after the first write process is completed. Therefore, if a new write request occurs before hold counter 22b is updated, hold counter 22b and VCOM counter 22a have different values, which may result in the timer circuit 23 being started redundantly and a write inhibition period being initiated. In contrast, the driving method shown in FIG. 6 can prevent the timer circuit 23 from being started redundantly and a write inhibition period being initiated in the above-described case.

[0042] When a write request at timing T1 (see FIG. 4) occurs, the write request at timing T1 is recorded in the processing stack (queue structure). The value of the hold counter is then compared with the value of the VCOM counter. If they do not match, it is determined that this is the first write process since the voltage polarity was reversed, and the timer circuit 23 is activated to start a write inhibit period. If a new write request (a write request at timing T2) occurs during this write inhibit period, the control unit 20 determines whether the first write process since the polarity was reversed has already occurred based on whether the timer circuit 23, which measures the write inhibit period when a write request occurs, is activated or whether display data for displaying an image by executing the write process is being transferred to the liquid crystal display unit 11.

[0043] This determination is made when hold counter 22b is updated at the time when the write process in response to the write request at timing T1 is completed, so when a write request at timing T2 occurs consecutively to the write request at timing T1, the value of VCOM counter 22a and the value of hold counter 22b do not match. Therefore, in the driving method shown in Fig. 6, in order to determine whether the write process in response to the write request at timing T1 has already occurred, it is determined whether the timer circuit 23 has been started by the write process in response to the write request at timing T1, or whether the timer circuit 23 has finished counting, has transitioned to the write process, and is currently transferring display data, thereby determining whether the first write request after polarity inversion exists.

[0044] Because there is the first write request after the polarity inversion (the write request at timing T1), the write request at timing T2 is recorded in the processing stack (queue structure) as the next process to be performed after the write request at timing T1, and the processing of the write request at timing T2 is put on hold. Even if the next write request (the write request at timing T3) occurs after the write request at timing T2, it is processed in the same way as the write request at timing T2, and the write request at timing T3 is recorded in the processing stack (queue structure) as the next process to be performed after the write request at timing T2, and the processing of the write request at timing T3 is put on hold.

[0045] The control unit 20 transfers display data to the liquid crystal display unit 11 based on the write request at time T1. Upon completing the write process, the control unit 20 executes the write request at time T2, which follows the write request at time T1 and is stored in the queue stack. Subsequently, the control unit 20 sequentially executes the write requests stored in the queue stack. When the write process is completed, the control unit 20 deletes the executed write request from the queue stack. If the timer circuit 23 has not yet started for the first write process after the polarity reversal or if the control unit 20 is not currently transferring display data, the control unit 20 determines that the first write request after the polarity reversal does not exist. The control unit 20 then turns on the voltage polarity reversal prohibition signal to prohibit the voltage polarity reversal, and proceeds to the write process flow shown in FIG. 5. Specifically, the control unit 20 determines whether the count value of the VCOM counter 22a and the count value of the holding counter 22b match. If they do not match, the control unit 20 activates the timer circuit 23 to measure the time remaining until the write prohibition period expires. Upon expiration of the write prohibition period, the control unit 20 starts the write process. Furthermore, if the count value of the VCOM counter 22a and the count value of the holding counter 22b match, the control unit 20 transfers display data based on the write request to the liquid crystal display unit 11 and executes the write process.

[0046] The voltage polarity inversion prohibition signal that has been turned on continues as long as there is a write request recorded in the processing stack. Then, when all write processes based on the write requests in the processing stack are completed and the processing stack becomes empty, the voltage polarity inversion prohibition signal changes from on to off. When the voltage polarity inversion prohibition signal turns off, the control unit 20 performs voltage polarity inversion in response to the timing for voltage polarity inversion. Here, the control unit 20 may perform voltage polarity inversion as soon as the voltage polarity inversion prohibition signal turns off, without waiting for the timing for polarity inversion. This allows voltage polarity inversion to be performed as soon as possible when polarity inversion is not being performed, thereby preventing burn-in problems.

[0047] Furthermore, when the voltage polarity inversion prohibition signal is turned on, the control unit 20 may count the number of times that polarity inversion has not been performed consecutively due to the polarity inversion prohibition signal, and if the number of times reaches a preset threshold, the voltage polarity may be inverted at the time the voltage polarity inversion prohibition signal transitions from on to off, without waiting for the timing of polarity inversion to arrive. This allows the voltage polarity to be inverted as soon as possible, before burn-in of the liquid crystal occurs due to polarity inversion not being performed for a while, thereby preventing the problem of burn-in.

[0048] After all write processes based on write requests recorded in the processing stack are completed and the voltage polarity inversion prohibition signal is turned off, if a new write request occurs before the timing for the next voltage polarity inversion arrives, the voltage polarity inversion prohibition signal is turned on again and the count values ​​of the VCOM counter 22a and the hold counter 22b are compared. Because voltage polarity inversion has not been performed, the count values ​​of the VCOM counter 22a and the hold counter 22b match, and the write process is immediately executed and the display data is transferred to the LCD. Once the display data transfer is complete, the processing stack detects whether the next write request is waiting, and if a waiting write request exists, the display data based on that request is transferred to the LCD. Once the display data transfer is complete and no next write request is waiting in the processing stack, the voltage polarity inversion prohibition signal is turned off, allowing voltage polarity inversion.

[0049] The control unit 20 counts the number of consecutive times that polarity reversal is not performed due to the polarity reversal prohibition signal. If the count reaches a preset threshold, the control unit 20 puts the write request recorded in the queue stack on hold when the ongoing write process ends and turns off the voltage polarity reversal prohibition signal. After the voltage polarity reversal is performed, the control unit 20 resumes the write process based on the queued write request in the queued stack. In this case, the VCOM counter 22a is incremented because the voltage polarity reversal is performed. Since the comparison values ​​of the VCOM counter 22a and the holding counter 22b do not match, the timer circuit 23 starts based on the queued write request and starts a write prohibition period. When the write prohibition period expires, the control unit 20 starts the write process to the liquid crystal display. Therefore, the driving method according to the embodiment puts the write request in the queued stack on hold and prioritizes voltage polarity reversal. Even if the write process is resumed after the voltage polarity reversal, the write process can be performed without overlapping with the write prohibition period associated with the voltage polarity reversal without any additional processing.

[0050] Fig. 6 is a diagram showing a processing flow when write requests are generated successively. As shown in Fig. 6, in the driving method according to the embodiment, when the control unit 20 receives a write request (step S10), it determines whether the timer circuit 23 is running or display data is being transferred at that time (step S11). If the timer circuit 23 is running or display data is being transferred in step S11, the control unit 20 puts the processing of the write request on hold and repeats the determination until the write processing being processed is completed (step S12).

[0051] On the other hand, if the timer circuit 23 is not running and the display data is not being transferred in the write step in step S11, the control unit 20 inhibits polarity inversion of the voltage applied to the liquid crystal 14a (polarity inversion inhibit step S13). The control unit 20 then compares the value of the VCOM counter 22a with the value of the hold counter (determination step S14). If the value of the VCOM counter 22a and the value of the hold counter are different from each other (i.e., if the value of the VCOM counter 22a and the value of the hold counter do not match), the control unit 20 activates the timer circuit 23 (determination step S15). The activated timer circuit 23 is set with a time until the write inhibit period expires, and the control unit 20 starts transferring image data (transferring display data to the memory element 12) when the write inhibit period expires (determination step S18). Through this control, the control unit 20 delays the write process in response to the write request until the write inhibit period has elapsed. On the other hand, if the value of the VCOM counter 22a and the value of the holding counter are the same in judgment step S14, the control unit 20 starts the write process (transfer of display data to the memory element 12) in response to the write request without waiting for the write prohibition period to elapse (judgment step S17).

[0052] In the driving method according to the embodiment shown in FIG. 6, the write process is executed in response to the first write request that occurs after the polarity of the voltage is reversed, thereby preventing the timer circuit 23 from being started redundantly and the write inhibition period from being started when new write requests occur consecutively.

[0053] Furthermore, in the driving method according to the embodiment, even if the writing process overlaps with the timing of polarity reversal of the voltage applied to the liquid crystal 14a, by skipping the polarity reversal of the voltage applied to the liquid crystal 14a as described above, it is possible to prevent the writing process from overlapping with the timing of polarity reversal of the voltage applied to the liquid crystal 14a, and it is possible to suppress, for example, image writing errors in the liquid crystal display unit 11.

[0054] Next, an example of the polarity reversal step in the driving method according to the embodiment will be described with reference to FIG.

[0055] As shown in FIG. 7, in the polarity reversal step of the embodiment, when the timing for reversing the polarity of the voltage applied to the liquid crystal 14a (VCOM polarity reversal timing) arrives (polarity reversal step S21), the control unit 20 determines whether or not the polarity reversal of the voltage applied to the liquid crystal 14a is prohibited (polarity reversal step S22). If it is determined in polarity reversal step S21 that the polarity reversal is not prohibited, the control unit 20 performs the polarity reversal of the voltage applied to the liquid crystal 14a (VCOM polarity reversal) (polarity reversal step S23). Thereafter, the control unit 20 increments the value of the VCOM counter 22a by one. On the other hand, if it is determined in polarity reversal step S21 that the polarity reversal is prohibited, the control unit 20 does not perform the polarity reversal of the voltage applied to the liquid crystal 14a (VCOM polarity reversal) (polarity reversal step S25). The polarity reversal step in the driving method according to the embodiment is performed as described above.

[0056] Next, with reference to FIG. 8, the operation timing of the driving method according to the embodiment will be described.

[0057] In FIG. 8, "VCOM" indicates the period of VCOM polarity inversion, "VCOM counter" indicates the value (count value) of the VCOM counter 22a, "write process" indicates the timing at which the write process is executed, and "hold counter" indicates the value (count value) of the hold counter 22b.

[0058] The VCOM counter 22a shown in FIG. 8 is an increment counter whose count value increases from 0 to 5 each time the VCOM polarity is inverted. The count value of the hold counter 22b is updated by storing the count value of the VCOM counter 22a at the time of the write operation. With this configuration, the count values ​​of the VCOM counter 22a and the hold counter 22b do not match at the time of the first write request after the VCOM polarity is inverted. However, at the time of the second or subsequent write request after the VCOM polarity is inverted, the count values ​​of the VCOM counter 22a and the hold counter 22b match. With this configuration, the control unit 20 can determine whether the write operation performed in response to the write request is the first write operation after the VCOM polarity is inverted by comparing the count values ​​of the VCOM counter 22a and the hold counter 22b in the determination process.

[0059] The driving method according to the above-described embodiment can be realized, for example, by executing a prepared program on a computer such as the CPU 21. This program causes the computer to execute the above-described polarity reversal process, writing process, and determination process.

[0060] As described above, the driving device of the embodiment includes a control unit 20 that controls the liquid crystal display unit 11, and the control unit 20 is configured to be able to execute a polarity inversion process that inverts the polarity of the voltage applied to the liquid crystal 14a of the liquid crystal display unit 11 at regular intervals, a write process that displays an image on the liquid crystal display unit 11 in response to an image write request, and a judgment process that judges before the write process whether the write process is the first write process after the polarity inversion.If the judgment process judges that the write process is the first write process after the polarity inversion, the execution of the write process is delayed until a preset write prohibition period has elapsed, and if the judgment process judges that the write process is not the first write process after the polarity inversion, the write process is executed without waiting for the write prohibition period to elapse.

[0061] The drive device according to the embodiment delays the first write process after the voltage polarity is reversed until the write prohibition period has elapsed, and executes write processes other than the first write process after the voltage polarity is reversed without waiting for the write prohibition period to elapse. This improves the real-timeness of image display on the liquid crystal display unit 11 while preventing write processes from overlapping with the write prohibition period. Therefore, the drive device according to the embodiment can properly display images. Furthermore, in the drive device according to the embodiment, the determination process needs to be executed only at the timing of the write process, thereby suppressing an increase in power consumption.

[0062] Furthermore, in the driving device according to the embodiment, when the timing of voltage polarity reversal in the polarity reversal process overlaps with the write process, the control unit 20 executes the write process without reversing the voltage polarity at that timing.

[0063] In the driving device of the embodiment, when the timing of the write process and the voltage polarity reversal in the polarity reversal process overlap, the write process is performed without reversing the voltage polarity at that timing, thereby improving the real-time nature of the image displayed on the liquid crystal display unit 11.

[0064] Furthermore, in the driving device according to the embodiment, the control unit 20 includes a VCOM counter 22a that counts the number of voltage polarity reversals each time the voltage polarity is reversal in the polarity reversal process, and a holding counter 22b that stores the count value of the VCOM counter 22a during the write process. When a write request is received, the control unit 20 executes a determination process, and in the determination process, it compares the number of voltage polarity reversals counted by the VCOM counter 22a with the count value stored in the holding counter 22b to determine whether the write process is the first write process after the polarity reversal.

[0065] In the determination process, the driving device of the embodiment can determine whether the write process is the first write process after the polarity reversal by comparing the number of times the voltage polarity reversal counted by the VCOM counter 22a with the count value stored in the holding counter 22b, and can control the execution timing of the write process according to the determination result, thereby allowing the image to be displayed properly on the liquid crystal display unit 11.

[0066] In addition, in the drive device according to the embodiment, the write inhibit period is set to start when the first write request is made after the polarity is reversed and to end before the next polarity reversal.

[0067] The driving device according to the embodiment can suppress image writing errors by providing a write inhibit period when the first write request is made after polarity reversal. With this configuration, the driving device according to the embodiment can properly display images on the liquid crystal display unit 11.

[0068] Furthermore, in the driving device according to the embodiment, the control unit 20 counts the number of times that the write process is executed without reversing the voltage polarity at the timing when the timing of the voltage polarity reversal in the polarity reversal process overlaps with the write process, and when the count reaches a predetermined number, puts the write request on hold and allows the voltage polarity reversal, and when the voltage polarity reversal is performed, prohibits the voltage polarity reversal and resumes the write process associated with the write request.

[0069] By performing the polarity inversion of the voltage as described above, the driving device according to the embodiment can suppress burn-in of the liquid crystal, which occurs when polarity inversion is not performed for a while.

[0070] Furthermore, in the driving device according to the embodiment, the control unit 20 determines whether the first write process after polarity reversal has already occurred based on whether the timer circuit 23, which measures the write prohibition period when a write request is made, is activated or based on whether display data for displaying an image by executing the write process when a write request is made is transferred to the liquid crystal display unit 11.

[0071] Even when write requests are generated consecutively, the driving device of the embodiment can determine whether the timer circuit 23 is running or not or whether display data is being transferred or not, thereby making it possible to know whether the first write request after the voltage polarity is reversed has already been processed or not, thereby preventing the timer circuit 23 from being started redundantly and setting a write prohibition period.

[0072] As described above, the electronic watch 100 according to the embodiment comprises a timing unit 30 that measures the current time, a liquid crystal display unit 11 that displays an image representing the current time measured by the timing unit 30, and a control unit 20 that controls the liquid crystal display unit 11. The control unit 20 is configured to be able to execute a polarity inversion process that inverts the polarity of the voltage applied to the liquid crystal 14a of the liquid crystal display unit 11 at regular intervals, a write process that displays an image on the liquid crystal display unit 11 in response to an image write request, and a judgment process that determines before the write process whether the write process is the first write process after polarity inversion. If the judgment process determines that the write process is the first write process after polarity inversion, the execution of the write process is delayed until a preset write prohibition period has elapsed, and if the judgment process determines that the write process is not the first write process after polarity inversion, the write process is executed without waiting for the write prohibition period to elapse.

[0073] The electronic timepiece 100 according to the embodiment delays the first write process after a voltage polarity reversal until the write prohibition period has elapsed, and executes write processes other than the first write process after a voltage polarity reversal without waiting for the write prohibition period to elapse, thereby improving the real-timeness of images displayed on the liquid crystal display unit 11 while preventing write processes from overlapping with the write prohibition period. Therefore, the electronic timepiece 100 according to the embodiment can properly display images. Furthermore, in the electronic timepiece 100 according to the embodiment, the determination process only needs to be executed at the timing of the write process, thereby suppressing increases in power consumption.

[0074] As described above, the driving method according to the embodiment includes a polarity inversion step of inverting the polarity of the voltage applied to the liquid crystal 14a of the liquid crystal display unit 11 at regular intervals, a writing step of displaying an image on the liquid crystal display unit 11 in response to a request to write an image, and a determination step of determining, before the writing step, whether the writing step is the first writing step after the polarity inversion. If it is determined in the determination step that the writing step is the first writing step after the polarity inversion, the execution of the writing step is delayed until a preset write prohibition period has elapsed. If it is determined in the determination step that the writing step is not the first writing step after the polarity inversion, the writing step is executed without waiting for the write prohibition period to elapse.

[0075] In the driving method according to the embodiment, the first writing step after the polarity of the voltage is reversed is delayed until the write inhibit period has elapsed, and writing steps other than the first writing step after the polarity of the voltage is reversed are executed without waiting for the write inhibit period to elapse. This improves the real-timeness of the image displayed on the liquid crystal display unit 11 while preventing the writing steps from overlapping with the write inhibit period. Therefore, the driving method according to the embodiment can display the image properly. Furthermore, in the driving method according to the embodiment, the determination step needs to be executed only at the timing of the writing step, thereby suppressing an increase in power consumption.

[0076] As described above, the program of the embodiment causes a computer to execute a polarity inversion process that inverts the polarity of the voltage applied to the liquid crystal 14a of the liquid crystal display unit 11 at regular intervals, a write process that displays an image on the liquid crystal display unit 11 in response to an image write request, and a determination process that determines before the write process whether the write process is the first write process after the polarity inversion.If the determination process determines that the write process is the first write process after the polarity inversion, the execution of the write process is delayed until a preset write prohibition period has elapsed, and if the determination process determines that the write process is not the first write process after the polarity inversion, the write process is executed without waiting for the write prohibition period to elapse and without any delay.

[0077] In the program according to the embodiment, the first write process after a voltage polarity reversal is delayed until the write prohibition period has elapsed, and write processes other than the first write process after a voltage polarity reversal are executed without waiting for the write prohibition period to elapse. This improves the real-timeness of images displayed on the liquid crystal display unit 11 while preventing write processes from overlapping with the write prohibition period. Therefore, the electronic timepiece 100 according to the embodiment can properly display images. Furthermore, in the program according to the embodiment, the determination process only needs to be executed at the timing of the write process, thereby suppressing increases in power consumption.

[0078] The contents disclosed in the above embodiments can be implemented in appropriate combinations. [Explanation of symbols]

[0079] 10:LCD display device 11: liquid crystal display unit, 11a: pixel, 12: memory element 13: display voltage supply driver, 14: display element, 14a: liquid crystal 14b: pixel electrode, 14c: common electrode, 15a: data bus line 15b: Gate bus line 20: Control unit 30: Timing section 100: Electronic clock, 101: Display drive circuit, 101a: Data driver 101b: Gate driver, 101c: VCOM driver

Claims

1. a control unit for controlling the liquid crystal display unit; the control unit is configured to be able to execute a polarity inversion process for inverting the polarity of a voltage applied to the liquid crystal of the liquid crystal display unit at a fixed cycle; a writing process for displaying an image on the liquid crystal display unit in response to a request to write the image; and a determination process for determining, before the writing process, whether the writing process is the first writing process after the polarity inversion; if it is determined in the determination process that the writing process is the first writing process after the polarity inversion, the control unit delays execution of the writing process until a preset write prohibition period has elapsed; and if it is determined in the determination process that the writing process is not the first writing process after the polarity inversion, the control unit executes the writing process without waiting for the write prohibition period to elapse. A drive device characterized by:

2. When a timing of voltage polarity reversal in the polarity reversal process overlaps with the writing process, the control unit executes the writing process without reversing the voltage polarity at the timing. The drive device according to claim 1 .

3. The control unit includes a VCOM counter that counts the number of voltage polarity reversals each time the voltage polarity is reversed in the polarity reversal process, and a holding counter that stores the count value of the VCOM counter during the write process, and executes the determination process when the write request is made, and in the determination process, determines whether the write process is the first write process after the polarity reversal by comparing the number of voltage polarity reversals counted by the VCOM counter with the count value stored in the holding counter.

3. The drive device according to claim 1 or 2.

4. the write inhibit period is set to start when the first write request is made after the polarity reversal and to end before the next polarity reversal.

3. The drive device according to claim 1 or 2.

5. the control unit counts the number of times the write process has been executed without reversing the polarity of the voltage at a timing when the timing of the polarity reversal of the voltage in the polarity reversal process overlaps with the write process, and when the count reaches a predetermined number, puts the write request on hold and permits the polarity reversal of the voltage, and when the polarity reversal of the voltage is performed, prohibits the polarity reversal of the voltage and resumes the write process associated with the write request. The drive device according to claim 2 .

6. The control unit When the write request is made, determining whether the first writing process after the polarity reversal has already occurred based on whether a timer circuit for measuring the write inhibit period has been activated or based on whether display data for displaying the image by the execution of the writing process has been transferred to the liquid crystal display unit; The drive device according to claim 3 .

7. a timekeeping unit that keeps track of the current time; a liquid crystal display unit that displays an image representing the current time measured by the clock unit; a control unit that controls the liquid crystal display unit; Equipped with the control unit is configured to be able to execute a polarity reversal process for reversing the polarity of a voltage applied to the liquid crystal of the liquid crystal display unit at a fixed cycle; a writing process for displaying an image on the liquid crystal display unit in response to an image writing request; and a determination process for determining, before the writing process, whether the writing process is the first writing process after the polarity reversal; if it is determined in the determination process that the writing process is the first writing process after the polarity reversal, the control unit delays execution of the writing process until a preset write prohibition period has elapsed; and if it is determined in the determination process that the writing process is not the first writing process after the polarity reversal, the control unit executes the writing process without waiting for the write prohibition period to elapse. An electronic watch characterized by:

8. a polarity inversion step of inverting the polarity of a voltage applied to the liquid crystal of the liquid crystal display unit at a constant cycle; a writing step of displaying the image on the liquid crystal display unit in response to a request to write the image; a determination step, prior to the writing step, of determining whether the writing step is the first writing step after the polarity reversal; Equipped with When it is determined in the determination step that the writing step is the first writing step after the polarity reversal, the execution of the writing step is delayed until a preset write inhibit period has elapsed, and when it is determined in the determination step that the writing step is not the first writing step after the polarity reversal, the writing step is executed without waiting for the write inhibit period to elapse. A driving method characterized by the above.

9. a polarity inversion process for inverting the polarity of the voltage applied to the liquid crystal of the liquid crystal display unit at a fixed cycle; a write process for displaying the image on the liquid crystal display unit in response to a write request for the image; a determination process for determining, before the writing process, whether the writing process is the first writing process after the polarity reversal; on the computer, When it is determined in the determination process that the writing process is the first writing process after the polarity reversal, the execution of the writing process is delayed until a preset write prohibition period has elapsed, and when it is determined in the determination process that the writing process is not the first writing process after the polarity reversal, the writing process is executed without waiting for the write prohibition period to elapse and without any delay. A program characterized by:

Images