Control device, control method, and display apparatus

Abstract

To suppress visual recognition of flicker due to fluctuation of a refresh rate.SOLUTION: A control device (11) that controls driving of a display panel (10) includes a period acquisition unit (22) that acquires a first drive period in which driving is performed with a positive polarity and a second drive period in which driving is performed with a negative polarity, and a polarity instruction unit (23) and a polarity determination unit (21) that control driving such that a polarity corresponding to a shorter drive period of the first drive period and the second drive period is longer than a polarity corresponding to a longer drive period.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device and a control method for controlling the driving of a display panel, and a display device. [Background technology]

[0002] Recently, display devices equipped with a variable refresh rate synchronization function that can dynamically change the refresh rate to track a variable frame rate video source have been used primarily for gaming. However, when the refresh rate changes, the gamma characteristics may change, potentially causing a change in the overall brightness of the screen. Therefore, fluctuations in the refresh rate can cause the brightness to fluctuate, which may be perceived as flicker.

[0003] In response to this, Patent Document 1 discloses a liquid crystal display device that changes the relationship between the drive voltage of the liquid crystal panel and the gradation of the display data according to the refresh rate so that the gamma value is maintained even when the refresh rate changes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-330292 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors of the present invention have found a cause of flicker caused by variations in refresh rate other than the gamma characteristic, and have devised the following solution.

[0006] An object of one aspect of the present invention is to suppress the visibility of flicker caused by fluctuations in refresh rate. [Means for solving the problem]

[0007] In order to solve the above problem, a control device according to one embodiment of the present invention is a control device that controls the driving of a display panel, and includes an acquisition unit that acquires a first driving period for driving with positive polarity and a second driving period for driving with negative polarity, and a control unit that controls the driving so that the polarity corresponding to the shorter driving period of the first driving period or the second driving period is longer than the polarity corresponding to the longer driving period.

[0008] A control method according to another aspect of the present invention is a control method for controlling the driving of a display panel, and includes an acquisition step of acquiring a first drive period for driving with positive polarity and a second drive period for driving with negative polarity, and a control step of controlling the drive so that the drive period of the polarity corresponding to the shorter drive period of the first drive period or the second drive period is longer than the drive period of the polarity corresponding to the longer drive period. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to suppress the visibility of flicker caused by fluctuations in the refresh rate. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a schematic configuration of a display device according to an embodiment of the present invention. [Figure 2] 10 is a flowchart showing the flow of a polarity determination process in a control device of the display device. [Figure 3] 10 is a timing chart showing an example of time-varying changes in various signals generated by the control device and the visibility of flicker on the display panel of the display device. [Figure 4] FIG. 10 is a block diagram showing a schematic configuration of a display device according to another embodiment of the present invention. [Figure 5] 10 is a flowchart showing the flow of a polarity determination process in a control device of the display device. [Figure 6]10 is a flowchart showing the flow of a polarity determination process in a control device of a display device according to yet another embodiment of the present invention. [Figure 7] FIG. 10 is a block diagram showing a schematic configuration of a display device according to yet another embodiment of the present invention. [Figure 8] 10 is a flowchart showing the flow of a polarity determination process in a control device of the display device. [Figure 9] 10 is a timing chart showing an example of time-varying changes in various signals generated by the control device and the visibility of flicker on the display panel of the display device. [Figure 10] 10 is a flowchart showing the flow of a polarity determination process in a control device of a display device according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail. For the sake of convenience, components having the same functions as those in the embodiments will be denoted by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0012] [Embodiment 1] An embodiment of the present invention will be described with reference to FIGS.

[0013] Fig. 1 is a block diagram showing a schematic configuration of a display device according to this embodiment. As shown in Fig. 1, the display device 1 includes a display panel 10 and a control device 11. The display device 1 according to this embodiment supports a variable refresh rate (VRR).

[0014] (display panel) The display panel 10 has a screen and is configured, for example, by an oxide semiconductor liquid crystal display panel as an active matrix liquid crystal display panel. An oxide semiconductor liquid crystal display panel is a liquid crystal display panel that employs oxide semiconductor TFTs (Thin Film Transistors) as some or all of the switching elements provided corresponding to at least one of a plurality of two-dimensionally arranged pixels. An oxide semiconductor TFT is a TFT that uses an oxide semiconductor in the semiconductor layer. An example of an oxide semiconductor is an oxide semiconductor (InGaZnO-based oxide semiconductor) that uses oxides of In, Ga, and Zn.

[0015] Oxide semiconductor TFTs have a large current flow in the on state and a small leakage current in the off state. Therefore, by using oxide semiconductor TFTs as switching elements, it is possible to improve the pixel aperture ratio and reduce the refresh rate of the screen display to about 1 Hz. Reducing the refresh rate also results in power savings. Note that improving the pixel aperture ratio has the effect of brightening the display, or, when the display brightness is to be the same as that of a CG silicon liquid crystal display panel, it results in power savings by reducing the amount of light from the backlight. Note that the present invention is not limited to display devices using oxide semiconductor TFTs, but can also be applied to display devices with a changeable refresh rate.

[0016] The display panel 10 is driven using various polarity inversion methods, which invert the polarity of the pixels of the display panel 10 every frame. Hereinafter, the polarity when a positive voltage with respect to the common electrode is applied to a pixel electrode will be referred to as positive polarity, and the polarity when a negative voltage with respect to the common electrode is applied to a pixel electrode will be referred to as negative polarity.

[0017] (Cause of flicker) Here, the cause of flicker due to variations in refresh rate will be described with reference to part of FIG.

[0018] 3 is a timing chart showing an example of the time change of various signals generated by the control device 11 and the visibility of flicker on the display panel 10. In FIG. 3, a timing chart of the visibility of flicker and the applied voltage (drive voltage) is shown in order from top to bottom.

[0019] As shown in FIG. 3, the applied voltage is an H-side voltage corresponding to positive polarity in the first frame from the start, inverted to an L-side voltage corresponding to negative polarity in the next second frame, inverted to an H-side voltage in the next third frame, and so on for each frame thereafter.

[0020] In the example of Figure 3, the refresh rate of the H-side voltage is lower than the refresh rate of the L-side voltage. That is, the frame period of the H-side voltage is longer than the frame period of the L-side voltage. Therefore, the difference between the total period of the H-side voltage and the total period of the L-side voltage, i.e., the polarity bias, of the applied voltage increases over time. At this time, the visibility of flicker starts from 0 and increases over time. That is, it can be understood that flicker is caused by polarity bias.

[0021] (control device) The control device 11 controls the driving of the display panel 10, and is, for example, a so-called COG (Chip on Glass) driver mounted on the glass substrate of the display panel 10. The control device 11 acquires display data from an external device (for example, a broadcast receiver, a game console, etc.), and drives the display panel 10 so that a display based on the display data is performed on the screen of the display panel 10. The display data includes image data, a synchronization signal, a refresh rate, etc.

[0022] As shown in FIG. 1, the control device 11 includes a TG 20 (timing generator), a polarity determination unit 21, a period acquisition unit 22 (acquisition unit), a polarity instruction unit 23 (control unit), and a DAC 24 (Digital-to-Analog Converter).

[0023] Based on the synchronization signal and refresh rate in the display data, the TG 20 generates a timing signal for driving the display panel 10. The TG 20 outputs the generated timing signal to the polarity determination unit .

[0024] The polarity determination unit 21 determines the polarity for driving the display panel 10 for each frame based on a timing signal from the TG 20. The polarity determination unit 21 outputs a signal to the DAC 24 according to the determined polarity.

[0025] In this embodiment, the polarity determination unit 21 includes a first counter 30 that measures a period during which the determined polarity is positive as a first period, and a second counter 31 that measures a period during which the determined polarity is negative as a second period. The first period corresponds to a first drive period during which the display panel 10 is driven with positive polarity. The second period corresponds to a second drive period during which the display panel 10 is driven with negative polarity. The polarity determination unit 21 sends the first and second periods measured by the first counter 30 and the second counter 31 to the period acquisition unit 22 for a predetermined period (e.g., 10 seconds).

[0026] In this embodiment, when the correction signal from the polarity instruction unit 23 is at H (high) level (e.g., 3.3 V), the polarity determination unit 21 determines the polarity to be the polarity corresponding to the shorter of the first and second periods. On the other hand, when the correction signal is at L (low) level (e.g., 0.0 V), the polarity determination unit 21 determines the polarity so that the polarity is reversed every frame.

[0027] The period acquisition unit 22 acquires the first period and the second period in the predetermined period from the polarity determination unit 21. The period acquisition unit 22 sends the acquired first period and second period to the polarity indication unit .

[0028] The polarity instruction unit 23 instructs the polarity determination unit 21 to correct the bias in polarity determined by the polarity determination unit 21. Specifically, the polarity instruction unit 23 calculates the difference between the first period and the second period from the period acquisition unit 22, and generates a correction signal that is at an H level only during the period of the difference. The polarity instruction unit 23 outputs the generated correction signal to the polarity determination unit 21.

[0029] The DAC 24 applies a voltage corresponding to the image data in the display data to each pixel of the display panel 10 in accordance with the timing signal. In addition, the DAC 24 applies a voltage on the H (high) side relative to the common electrode voltage Vcom in the case of positive polarity, and applies a voltage on the L (low) side relative to the common electrode voltage Vcom in the case of negative polarity. Hereinafter, the above voltage may be referred to as the "applied voltage."

[0030] According to the above configuration, when a polarity imbalance occurs, i.e., when there is a difference between the first period and the second period, the polarity determination unit 21 maintains the polarity corresponding to the shorter of the first period and the second period. As a result, the polarity corresponding to the shorter period is longer than the polarity corresponding to the longer period. Therefore, the polarity imbalance is reduced, and the visibility of flicker can be reduced.

[0031] Furthermore, the polarity determination unit 21 maintains the polarity corresponding to the shorter period for the period of the difference, thereby eliminating the polarity imbalance and the possibility of flicker being visible.

[0032] 2 is a flowchart showing the flow of the polarity determination process (control method) in the control device 11 configured as described above. As shown in Fig. 2, first, the polarity determination unit 21 inverts the polarity for each frame, measures a first period in which the polarity is positive with a first counter 30, and measures a second period in which the polarity is negative with a second counter 31 (S10, acquisition step).

[0033] Next, the polarity determination unit 21 repeats step S10 until a predetermined period has elapsed (S11). When the predetermined period has elapsed, the polarity indication unit 23 calculates the difference between the first period and the second period (S12). If the difference is zero (YES in S13), the process returns to step S10 (S13). At this time, the first counter 30 and the second counter 31 may be reset.

[0034] If the difference is not zero (NO in S13), the polarity determination unit 21 maintains the polarity corresponding to the shorter of the first period and the second period (S14, control step). Next, the process waits until the difference period has elapsed (S15), and then returns to step S10 to repeat the above operation. At this time, the first counter 30 and the second counter 31 may be reset.

[0035] The details of Fig. 3 will be explained. Fig. 3 shows, from top to bottom, a timing chart of the visibility of the flicker, the applied voltage (drive voltage), the polarity signal, and the correction signal. The polarity signal is a signal indicating the polarity determined by the polarity determination unit 21.

[0036] As shown in Fig. 3, first, from the start time T0 until a predetermined period, the correction signal is at L level. Therefore, the polarity signal is at H level (e.g., 3.3 V) indicating positive polarity in the first frame from the start, inverts to L level (e.g., 0.0 V) indicating negative polarity in the second frame, inverts to H level in the third frame, and repeats this for each frame thereafter. Based on this polarity signal, the applied voltage is an H-side voltage corresponding to positive polarity in the first frame, inverts to an L-side voltage corresponding to negative polarity in the second frame, inverts to an H-side voltage corresponding to negative polarity in the third frame, and repeats this for each frame thereafter.

[0037] In the example of Figure 3, the refresh rate of the H-side voltage is lower than the refresh rate of the L-side voltage. That is, the frame period of the H-side voltage is longer than the frame period of the L-side voltage. Therefore, the difference between the total period of the H-side voltage and the total period of the L-side voltage increases over time. This causes the visibility of flicker to start from 0 and increase over time.

[0038] Next, at time T1, a predetermined period of time has elapsed since the start time T0, the correction signal is inverted to H level. Therefore, the polarity signal becomes L level, which indicates the polarity corresponding to the shorter of the first period and the second period, i.e., negative polarity. The period during which the correction signal is H level is the difference between the first period and the second period of the predetermined period.

[0039] Based on this polarity signal, the applied voltage becomes the L-side voltage from time T1 to time T2, when the difference has elapsed. As a result, the difference between the total period of the H-side voltage and the total period of the L-side voltage of the applied voltage decreases over time and becomes zero at time T2. Therefore, the visibility of flicker decreases over time and becomes zero at time T2.

[0040] Note that timing chart G100, indicated by the dashed-dotted line in FIG. 3, shows the case where the correction signal remains at the L level even after time T1, i.e., the polarity imbalance is not corrected. In this case, the visibility of flicker continues to increase, and eventually flicker becomes visible. Also, timing chart G110, indicated by the dashed-dotted line in FIG. 3, shows the case where the variable refresh rate is changed to a fixed refresh rate after time T1. In this case, the visibility of flicker decreases gradually, but it takes time for the visibility to reach zero.

[0041] At time T2, the correction signal is inverted to L level. Therefore, the polarity signal is inverted and repeated every frame, and the drive voltage is inverted and repeated every frame. In the example of FIG. 3, after time T2 has passed, the refresh rate of the drive voltage at H level is the same as the refresh rate of the drive voltage at L level. Therefore, even after a predetermined period has passed since time T2, the correction signal is maintained at L level.

[0042] (Additional notes) The TG 20 may determine the polarity for driving the display panel 10 for each frame. In this case, the polarity determination unit 21 corrects the polarity determined by the TG 20 based on a correction signal from the polarity instruction unit 23, and outputs a signal corresponding to the corrected polarity to the DAC 24.

[0043] [Embodiment 2] Another embodiment of the present invention will now be described with reference to FIGS.

[0044] Fig. 4 is a block diagram showing a schematic configuration of a display device of this embodiment. The display device shown in Fig. 4 differs from the display device shown in Fig. 1 in that a polarity determination unit 21a is provided instead of the polarity determination unit 21 and a period acquisition unit 22a is provided instead of the period acquisition unit 22, but the other configurations are the same.

[0045] 1, the polarity determination unit 21a does not include the second counter 31. Therefore, the polarity determination unit 21a sends a first period measured by the first counter 30 during a predetermined period (e.g., 10 seconds) to the period acquisition unit 22a.

[0046] 1, the period acquiring unit 22a newly includes a period calculating unit 32. The period calculating unit 32 uses the predetermined period and the first period from the polarity determining unit 21a to calculate a second period in which the polarity determined by the polarity determining unit 21a is negative, according to the following equation (1). This allows the period acquiring unit 22a to acquire the first period and the second period. Second period = predetermined period - first period (1).

[0047] The first counter 30 may be omitted and replaced with the second counter 31. In this way, the polarity determination unit 21a only needs to measure one of the first period and the second period using a counter, and the other period only needs to be calculated by the period acquisition unit 22a.

[0048] Fig. 5 is a flowchart showing the flow of polarity determination processing in the control device 11 configured as described above. The determination processing shown in Fig. 5 differs from the determination processing shown in Fig. 2 in that step S20 is provided instead of step S10 and step S21 is provided instead of step S12, but the remaining processing is the same.

[0049] In step S20, the polarity determination unit 21 inverts the polarity for each frame and measures a first period during which the polarity is positive using the first counter 30. In addition, in step S21, the period acquisition unit 22a calculates a second period during which the polarity is negative using a predetermined period and the first period, and the polarity indication unit 23 calculates the difference between the first period and the second period.

[0050] [Embodiment 3] Yet another embodiment of the present invention will be described with reference to Fig. 6. The display device of this embodiment has a configuration in which a polarity indicating section 23a is provided instead of the polarity indicating section 23 in the display device shown in Fig. 1.

[0051] The polarity indication unit 23a calculates the difference between the first period and the second period from the period acquisition unit 22, and when the difference is equal to or greater than a threshold value (e.g., 5 seconds), generates a correction signal that is at H level only for the period of the difference. The polarity indication unit 23 outputs the generated correction signal to the polarity determination unit 21.

[0052] As a result, when the visibility of flicker becomes equal to or greater than the flicker threshold corresponding to the threshold value of the difference, the polarity determination unit 21 maintains the polarity corresponding to the shorter of the first period and the second period. As a result, as described above, the visibility of flicker can be reduced and maintained below the flicker threshold. Furthermore, the polarity determination unit 21 maintains the polarity corresponding to the shorter period for the period of the difference. As a result, the polarity imbalance is eliminated, and the visibility of flicker is eliminated.

[0053] 6 is a flowchart showing the flow of polarity determination processing in the control device 11 configured as described above. As shown in FIG. 6, first, the polarity determination unit 21 inverts the polarity for each frame, measures a first period during which the polarity is positive using a first counter 30, and measures a second period during which the polarity is negative using a second counter 31 (S30). Next, the polarity indication unit 23a calculates the difference between the first period and the second period (S31). Next, the polarity indication unit 23a repeats steps S30 and S31 until the difference becomes equal to or greater than a threshold value.

[0054] If the difference is equal to or greater than the threshold, the polarity determination unit 21 maintains the polarity corresponding to the shorter of the first and second periods (S32). Next, the process waits until the difference period has elapsed (S33), and then returns to step S30 to repeat the above operation. At this time, the first counter 30 and the second counter 31 may be reset.

[0055] [Embodiment 4] Still another embodiment of the present invention will be described with reference to FIGS.

[0056] Fig. 7 is a block diagram showing a schematic configuration of a display device of this embodiment. The display device shown in Fig. 7 differs from the display device shown in Fig. 1 in that a polarity determination unit 40 is provided instead of the polarity determination unit 21, the period acquisition unit 22 is omitted, and a polarity indication unit 41 is provided instead of the polarity indication unit 23, but the other configurations are the same.

[0057] The polarity instruction unit 41 generates a correction signal that goes low for a predetermined period, goes high for the next predetermined period, and repeats this process. The polarity instruction unit 41 outputs the generated correction signal to the polarity determination unit 21.

[0058] 1, polarity determination unit 40 is different from polarity determination unit 21 shown in Fig. 1 in that when the correction signal from polarity instruction unit 23 is at H level, polarity determination unit 40 determines the polarity so that the ratio (drive ratio) of the polarity corresponding to the shorter of the first and second periods is higher than the polarity corresponding to the longer period, but is otherwise similar. For example, when the second period is shorter than the first period, polarity determination unit 40 determines the polarity so that the ratio of the number of positive polarity frames to the number of negative polarity frames is 1:2.

[0059] As a result, the polarity corresponding to the shorter period is longer than the polarity corresponding to the longer period, thereby reducing the polarity imbalance and reducing the possibility of flicker being visible.

[0060] 8 is a flowchart showing the flow of the polarity determination process in the control device 11 configured as described above. As shown in FIG. 8, first, steps S10 and S11 shown in FIG.

[0061] If the predetermined period has elapsed in step S11, the polarity determination unit 21 determines whether the first period and the second period are equal (S40). If the first period and the second period are equal (YES in S40), correction of polarity imbalance is not necessary, and the process returns to step S10. At this time, the first counter 30 and the second counter 31 may be reset.

[0062] If the first period and the second period are different (NO in S40), the polarity determination unit 21 determines the polarity so that the proportion of the polarity corresponding to the shorter of the first period and the second period is greater than the proportion of the polarity corresponding to the longer period (S41). Next, step S41 is repeated until the predetermined period has elapsed (S42). Thereafter, the process returns to step S10 and the above operation is repeated.

[0063] Fig. 9 is a timing chart showing an example of time variations of various signals generated by the control device 11 of this embodiment. Fig. 9 shows, from top to bottom, timing charts of the applied voltage, the polarity signal, and the correction signal.

[0064] As shown in Figure 9, the correction signal is at L level from the start time T0 until a predetermined period has elapsed. Therefore, the polarity signal is at H level indicating positive polarity in the first frame from the start, inverts to L level indicating negative polarity in the second frame, and inverts to H level in the third frame, and this is repeated for each frame thereafter. Based on this polarity signal, the applied voltage is at H level corresponding to positive polarity in the first frame, inverts to L level corresponding to negative polarity in the second frame, and inverts to H level in the third frame, and this is repeated for each frame thereafter.

[0065] Next, at time T1, when the predetermined period has elapsed from start time T0, the correction signal is inverted to H level. Therefore, the polarity signal has a higher proportion of polarities corresponding to the shorter of the first and second periods than the polarities corresponding to the longer of the first and second periods. In the example of FIG. 9, the polarity signal has a ratio of H level frames indicating positive polarity to L level frames indicating negative polarity = 1:2. Also, the H level polarity signal indicated by the dashed line in FIG. 9 becomes an L level polarity signal.

[0066] Next, at time T2, when the predetermined period has elapsed since time T1, the correction signal is inverted to L level. Therefore, the polarity signal is inverted and repeated every frame, and the applied voltage is inverted and repeated every frame. Note that the predetermined period from time T0 to time T1 may be different from the predetermined period from time T1 to time T2.

[0067] [Embodiment 5] Yet another embodiment of the present invention will be described with reference to Fig. 10. The display device of this embodiment has a configuration in which a polarity determination section 40a is provided instead of the polarity determination section 40 in the display device shown in Fig. 7.

[0068] The polarity determination unit 40a differs from the polarity determination unit 40 in that when the correction signal from the polarity indication unit 41 is at H level, the polarity determination unit 40a determines the polarity so that the polarity corresponding to the shorter of the first and second periods becomes the longer period, and the polarity corresponding to the longer period becomes the shorter period; otherwise, the configuration is similar.

[0069] As a result, the polarity corresponding to the shorter period is longer than the polarity corresponding to the longer period. Therefore, the polarity bias is reduced, and the visibility of flicker can be reduced. In particular, when the refresh rate does not change significantly, the polarity bias is reliably reduced, and the visibility of flicker can be reliably reduced.

[0070] Fig. 10 is a flowchart showing the flow of polarity determination processing in the control device 11 configured as described above. The determination processing shown in Fig. 10 differs from the determination processing shown in Fig. 8 in that step S50 is executed instead of step S41, but the other processing is the same.

[0071] In step S50, the polarity determination unit 21 determines the polarity so that the polarity corresponding to the shorter of the first and second periods becomes the longer period, and the polarity corresponding to the longer period becomes the shorter period.

[0072] [Software implementation example] The functions of the control device 11 (hereinafter referred to as the "device") can be realized by a program for causing a computer to function as the device, and a program for causing a computer to function as each control block of the device (particularly the polarity determination units 21, 21a, 40, 40a and the polarity indication units 23, 23a, 41).

[0073] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing the functions described in each of the above embodiments.

[0074] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0075] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit on which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention.

[0076] 〔summary〕 The control device 11 according to aspect 1 of the present invention is a control device 11 that controls the driving of the display panel 10, and includes an acquisition unit (period acquisition unit 22, 22a) that acquires a first driving period for driving with positive polarity and a second driving period for driving with negative polarity, and a control unit (polarity determination unit 21, 21a, 40, 40a and polarity indication unit 23, 23a, 41) that controls the driving so that the polarity corresponding to the shorter driving period of the first driving period or the second driving period is longer than the polarity corresponding to the longer driving period.

[0077] According to the above configuration, when a polarity imbalance occurs, i.e., when there is a difference between the first period and the second period, the control unit maintains the polarity corresponding to the shorter of the first period and the second period. As a result, the polarity corresponding to the shorter period is longer than the polarity corresponding to the longer period. Therefore, the polarity imbalance is reduced, and the visibility of flicker can be reduced.

[0078] The control device 11 according to aspect 2 of the present invention may further include, in the above aspect 1, two counters (first counter 30 and second counter 31) that measure the first driving period and the second driving period, respectively, and the acquisition unit may acquire the first driving period and the second driving period from the two counters, respectively.

[0079] The control device 11 according to aspect 3 of the present invention, in the above aspect 1, further includes a counter (first counter 30 or second counter 31) that measures one of the first driving period and the second driving period, and the acquisition unit may acquire one of the first driving period and the second driving period for a predetermined period from the counter, and calculate the other of the first driving period and the second driving period using the acquired driving period and the predetermined period.

[0080] In the control device 11 according to aspect 4 of the present invention, in the above aspects 1 to 3, the control unit may control the display panel 10 to drive the display panel 10 with a polarity corresponding to the shorter drive period for a period equal to the difference between the first drive period and the second drive period. In this case, the polarity imbalance is eliminated, and the possibility of visible flicker is eliminated.

[0081] In the control device 11 according to aspect 5 of the present invention, in any of aspects 1 to 3 above, the control unit may, in response to determining that the difference between the first drive period and the second drive period is equal to or greater than a threshold, control the display panel 10 to drive the display panel 10 with a polarity corresponding to the shorter drive period for the difference period. In this case, the polarity imbalance is eliminated, and the possibility of visible flicker is eliminated.

[0082] In the control device 11 according to a sixth aspect of the present invention, in any of the first to fifth aspects, the control unit may control the driving so that the polarity corresponding to the shorter driving period has a higher driving ratio than the polarity corresponding to the longer driving period. In this case, the polarity corresponding to the shorter period is longer than the polarity corresponding to the longer period. Therefore, the polarity bias is reduced, and the visibility of flicker can be reduced.

[0083] A control device 11 according to aspect 7 of the present invention may be configured such that, in aspects 1 to 5 above, the control unit drives the display panel 10 for the longer driving period with a polarity corresponding to the shorter driving period, while controlling the display panel 10 for the shorter driving period with a polarity corresponding to the longer driving period.

[0084] In this case, the polarity corresponding to the shorter period is longer than the polarity corresponding to the longer period. Therefore, the polarity bias is reduced, and the visibility of flicker can be reduced. In particular, when the refresh rate does not change significantly, the polarity bias is reliably reduced, and the visibility of flicker can be reliably reduced.

[0085] A display device 1 according to an eighth aspect of the present invention includes a display panel 10 and a control device 11 according to any one of the first to seventh aspects described above, which controls the driving of the display panel 10.

[0086] According to the above configuration, the same effects as those of the first aspect can be achieved.

[0087] A display device 1 according to a ninth aspect of the present invention may be configured such that, in the eighth aspect, the display panel 10 is a liquid crystal display panel.

[0088] A control method according to aspect 10 of the present invention is a control method for controlling the driving of a display panel 10, and includes an acquisition step for acquiring a first driving period for driving with positive polarity and a second driving period for driving with negative polarity, and a control step for controlling the driving so that the polarity corresponding to the shorter driving period of the first driving period or the second driving period is longer than the polarity corresponding to the longer driving period.

[0089] According to the above method, the same effects as those of the first aspect can be achieved.

[0090] The control device according to each aspect of the present invention may be realized by a computer. In this case, the control program of the control device that realizes the control device by the computer by making the computer operate as each part (software element) of the control device, and the computer-readable recording medium on which the control program is recorded, also fall within the scope of the present invention.

[0091] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. [Explanation of symbols]

[0092] 1 Display device 10 Display panel 11 Control Devices 20TG 21, 21a, 40, 40a Polarity determination unit (control unit) 22, 22a Period acquisition section (acquisition section) 23, 23a, 41 Polarity indicator (control unit) 24 DAC 30 First Counter 31 Second Counter 32 Period Calculation Section

Claims

1. A control device that controls the driving of a display panel, an acquisition unit that acquires a first drive period in which the pixel is driven with a positive polarity and a second drive period in which the pixel is driven with a negative polarity; a control unit that controls driving so that the polarity corresponding to the shorter drive period of the first drive period or the second drive period is longer than the polarity corresponding to the longer drive period.

2. further comprising two counters for measuring the first driving period and the second driving period, The control device according to claim 1 , wherein the acquisition unit acquires the first driving period and the second driving period from the two counters, respectively.

3. a counter that measures one of the first driving period and the second driving period; The control device according to claim 1, wherein the acquisition unit acquires one of the first driving period and the second driving period within a predetermined period from the counter, and calculates the other of the first driving period and the second driving period using the acquired driving period and the predetermined period.

4. The control device according to claim 1 , wherein the control unit controls the display panel to be driven with a polarity corresponding to the shorter drive period for a period equal to the difference between the first drive period and the second drive period.

5. 2. The control device according to claim 1, wherein the control unit controls the display panel to drive the display panel for a period of the difference with a polarity corresponding to the shorter drive period in response to determining that the difference between the first drive period and the second drive period is equal to or greater than a threshold value.

6. The control device according to claim 1 , wherein the control unit controls the driving so that the polarity corresponding to the shorter driving period has a higher driving ratio than the polarity corresponding to the longer driving period.

7. The control device according to claim 1, wherein the control unit controls the display panel to drive the display panel for the longer drive period with a polarity corresponding to the shorter drive period, while controlling the display panel to drive the display panel for the shorter drive period with a polarity corresponding to the longer drive period.

8. A display panel; A display device comprising: a control device according to claim 1 that controls driving of the display panel.

9. The display device according to claim 8 , wherein the display panel is a liquid crystal display panel.

10. A control method for controlling driving of a display panel, comprising: an acquiring step of acquiring a first driving period in which the pixel is driven with a positive polarity and a second driving period in which the pixel is driven with a negative polarity; and a control step of controlling driving so that the polarity corresponding to a shorter drive period of the first drive period or the second drive period is longer than the polarity corresponding to a longer drive period.

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