JP2019032559A - Display drive device, display device, and display drive method - Google Patents

Abstract

To provide a display drive device capable of preventing degradation of display quality due to stray capacitance of a signal line provided to a liquid crystal panel, a display device, and a display drive method.SOLUTION: A liquid crystal panel comprises: a common electrode; a plurality of pixel electrodes; a plurality of switching elements each connected to the respective pixel electrodes; and a plurality of signal lines connected to the plurality of switching elements, which are disposed being opposed to each other. The display drive device is configured to periodically generate blanking periods for turning OFF all of the plurality of switching elements. The display drive device includes a voltage application part configured to apply a predetermined voltage the electric potential difference of which with the common electrode is greater than zero to the signal lines within a partial time in the blanking period.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a display driving device and a display driving method for driving a liquid crystal panel. The present invention also relates to a display device including the display driving device.

  2. Description of the Related Art Conventionally, a display device including a liquid crystal panel and a display driving device that drives the display of the liquid crystal panel is known. In general, a liquid crystal panel includes a substrate having a common electrode, a plurality of pixel electrodes, a plurality of switching elements connected to the pixel electrodes, and a substrate having a plurality of signal lines connected to the plurality of switching elements. Liquid crystal material is enclosed in

  In order to display an image on the display surface of the liquid crystal panel, the display driving device controls on / off of a switching element provided in the liquid crystal panel, application of a voltage to a signal line, and the like. Specifically, the display driving device sequentially turns on one or a plurality of switching elements and supplies a voltage corresponding to an image to be displayed via a signal line connected to the on-state switching element to the on-state switching element. Apply to. In addition, after applying a voltage related to an image to each switching element, the display driving device turns off all the switching elements for a predetermined time and applies a predetermined voltage to a signal line connected to the switching element. The predetermined time is a time representing a so-called blanking period. For example, a display driving device used in the display device described in Patent Document 1 applies a voltage representing a black gradation to a signal line during a blanking period. The display driving device as described above applies voltage to the display surface of the liquid crystal panel by applying the voltage so that the time for applying the voltage related to the image to each switching element and the time for representing the blanking period are alternately repeated. Display still images or moving images.

JP 2008-268887 A

  In general, each signal line provided in the liquid crystal panel has a stray capacitance between the surrounding common electrode, pixel electrode, and other signal lines. The stray capacitance is in a state where it can be charged due to discharge or the like during the blanking period. Therefore, when a relatively high voltage is applied to each signal line after the blanking period, a relatively large current flows through each signal line due to an increase in charge stored in each stray capacitance, and a voltage is applied to each signal line. There is a possibility that the output voltage of the power supply for applying may temporarily decrease. When the output voltage of the power supply decreases, a voltage lower than the voltage to be applied next is applied to each signal line, so that an image of a gradation to be displayed cannot be displayed, and the display quality is deteriorated. There is a fear.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a display drive device, a display device, and a display drive that suppress deterioration in display quality caused by stray capacitance of a signal line provided in a liquid crystal panel. It is to provide a method.

  A display drive device according to the present invention includes a common electrode, a plurality of pixel electrodes, a plurality of switching elements connected to each pixel electrode, and a plurality of signal lines connected to the plurality of switching elements. In a display drive device in which a blanking period for periodically turning off all the switching elements of the liquid crystal panel is provided, a potential difference with the common electrode is zero within a part of the blanking period. A voltage applying unit that applies a predetermined voltage higher than the signal line to the signal line, and the voltage applying unit includes a part of the time and a series of periods including a display period excluding the blanking period. A voltage is repeatedly applied to each of the plurality of signal lines.

In the display driving device according to the present invention, the voltage application unit applies a voltage to each of the plurality of signal lines in the part of the time and in a display period excluding the blanking period thereafter. The voltage is applied so that the continuity of the above is maintained.
The display driving device according to the present invention is characterized in that no voltage is applied to the signal line during the remaining time in the blanking period.
Further, in the display driving device according to the present invention, the voltage application unit applies a voltage to each of the plurality of signal lines in the part of the time and in a display period excluding the blanking period thereafter. A voltage is applied so that the continuity of the period is maintained.
In the display driving device according to the present invention, the charge stored in the stray capacitance in the signal line is discharged due to the fact that no voltage is applied to the signal line in the remaining time in the blanking period. It is characterized by becoming a state.
Furthermore, the display driving device according to the present invention is characterized in that the end point of the part of time is within a predetermined time interval before the end of the blanking period.

  In the display driving apparatus according to the present invention, the voltage application unit applies the predetermined voltage to each of the plurality of signal lines only once within the partial time period.

  The display driving apparatus according to the present invention is characterized in that the voltage application section repeatedly applies the predetermined voltage to each of the plurality of signal lines over the part of time.

  The display driving apparatus according to the present invention is characterized in that the voltage application unit does not apply a voltage to the signal line during the remaining time in the blanking period.

  A display device according to the present invention includes the above-described display driving device, a common electrode, a plurality of pixel electrodes, a plurality of switching elements connected to each pixel electrode, and a plurality of signal lines connected to the plurality of switching elements. The display driving device applies a voltage to a signal line of the liquid crystal panel.

  In the display device according to the present invention, the liquid crystal panel is configured to perform black display when no potential difference is generated between the common electrode and the pixel electrode, and the voltage application unit is configured to perform the partial time period. The voltage representing the gray level on the white side of the halftone is applied to the signal line as the predetermined voltage.

  In the display device according to the present invention, the voltage application unit applies a voltage representing white gradation as the predetermined voltage to the signal line within the part of the time. To do.

  In the display device according to the present invention, the display driving device applies a voltage corresponding to display of an image to be displayed on the liquid crystal panel to the signal line during the blanking period. The voltage application unit is configured to apply the voltage initially applied to the signal line to the signal line as the predetermined voltage after the blanking period ends.

  A display driving method according to the present invention includes a common electrode, a plurality of pixel electrodes, a plurality of switching elements connected to each pixel electrode, and a plurality of signal lines connected to the plurality of switching elements. In a display driving method in which a blanking period for periodically turning off all the switching elements of the liquid crystal panel is provided, a potential difference from the common electrode is zero within a part of the blanking period. Is applied to each of the plurality of signal lines repeatedly within a series of periods including the part of the time and the display period excluding the blanking period. It is characterized by doing.

  According to the present invention, it is possible to suppress deterioration in display quality due to stray capacitance of signal lines provided in a liquid crystal panel.

1 is a block diagram illustrating a configuration of a display device in Embodiment 1. FIG. It is a schematic diagram which shows the structure of a liquid crystal panel. It is a figure which shows the equivalent circuit of each pixel. It is explanatory drawing explaining the timing which a display drive device applies a voltage to a source line. 6 is a block diagram illustrating a configuration of a display device according to Embodiment 2. FIG. It is explanatory drawing explaining the timing which a display drive device applies a voltage to a source line. FIG. 10 is an explanatory diagram illustrating timing when a display driving device according to a third embodiment applies a voltage to a source line. FIG. 10 is an explanatory diagram illustrating timing when a display driving device according to a fourth embodiment applies a voltage to a source line.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.

(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration of a display device according to Embodiment 1, and FIG. 2 is a schematic diagram illustrating a configuration of a liquid crystal panel. The display device 100 according to the first embodiment includes a liquid crystal panel 1, a display drive device 2, and a drive power supply unit 3. The display device 100 displays an image such as a still image or a moving image on the display surface of the liquid crystal panel 1 when the display driving device 2 drives the liquid crystal panel 1 with power supplied from the drive power supply unit 3.

  The liquid crystal panel 1 includes an array substrate 11 on which elements such as a TFT (Thin Film Transistor) 111 and a pixel electrode 112 are formed. In addition, the liquid crystal panel 1 includes a CF substrate 12 that is disposed so as to face the array substrate 11 and on which a color filter (CF), a common electrode 121, and the like are formed. The array substrate 11 and the CF substrate 12 are formed using, for example, glass as a base. Here, the pixel electrode 112 is formed on the array substrate 11 for each pixel, while the common electrode 121 is formed on the CF substrate 12 as one electrode common to the pixel electrodes 112. A gap is formed between the array substrate 11 and the CF substrate 12, and a liquid crystal layer is formed by sealing a liquid crystal substance in the gap.

  The display driving device 2 includes a control unit 21, a timing controller 22, a source driver 23, and a gate driver 24, and the drive of the liquid crystal panel 1 is controlled by the control unit 21 controlling each unit. The control unit 21 generates display data to be displayed on the liquid crystal panel 1 based on an image signal input from the outside, and outputs the display data to the timing controller 22. The image signal is input to the display device 100 through an input terminal (not shown) such as HDMI (High Definition Multimedia Interface: registered trademark), composite, or D terminal.

  Here, when the image signal input from the outside through the input terminal is a signal other than RGB such as a YCrCb signal, the display device 100 performs a process of converting the signal into an RGB signal in advance and unifying the signal format, You may make it input into the control part 21. FIG. Further, the display device 100 may perform image adjustment processing such as saturation and sharpness on an image signal input from the outside through the input terminal in advance, and then input the image signal to the control unit 21.

  The timing controller 22 outputs a control signal for controlling the driving of the source driver 23 and the gate driver 24 to each of the source driver 23 and the gate driver 24 based on the display data input from the control unit 21. The control unit 21 causes the timing controller 22 to output a control signal so that one frame image is displayed at a predetermined frame rate. The predetermined frame rate is, for example, 60 Hz.

The source driver 23 is connected to the source line 113. Based on the control signal input from the timing controller 22, the source driver 23 applies a voltage representing the gradation of the image to be displayed to the corresponding source line 113. The number of gradations in the source driver 23 is, for example, 256, and the number is not limited. In the first embodiment, the source driver 23 is configured to apply a voltage to all the connected source lines 113 at a time according to a line sequential method. The source driver 23 corresponds to the voltage application unit of the present invention. The source driver 23 may be configured to sequentially apply a voltage to each source line 113 in accordance with a dot sequential method. Further, the source driver 23 may be constituted by a plurality of ICs (Integrated Circuits) or may be constituted by one IC. Needless to say, the source driver 23 may be configured to apply a voltage representing a gray scale according to various inversion driving methods.

  The gate driver 24 is connected to the gate line 114. The gate driver 24 applies a voltage for controlling on / off of the TFT 111 to the gate line 114 based on the control signal input from the timing controller 22. At this time, the gate driver 24 may apply the voltage in line order according to the progressive method, or may apply the voltage according to the interlace method. The gate driver 24 may be composed of a plurality of ICs or a single IC.

  The drive power supply unit 3 includes a source power supply circuit 31 and a gate power supply circuit 32, and supplies power necessary for the operation of the display device 100 to each unit based on a command from the control unit 21. The source power supply circuit 31 is connected to the source driver 23 via, for example, a power supply line, and is a circuit for supplying power for the source driver 23 to apply a voltage related to the gradation of the image to the source line 113. The gate power supply circuit 32 is a circuit that is connected to the gate driver 24 via, for example, a power supply line, and supplies power for the gate driver 24 to apply a voltage related to on / off of the TFT 111 to the gate line 114.

  The display driving device 2 may be configured to apply a voltage to the common electrode 121 with power supplied from the driving power supply unit 3. At this time, the voltage applied to the common voltage may be periodically changed according to a so-called common inversion driving method.

  Next, the configuration of the liquid crystal panel 1 will be described in detail with reference to FIG. As shown in FIG. 2, the TFTs 111 and the pixel electrodes 112 formed on the array substrate 11 are arranged in a matrix (for example, 1024 in the row direction and 768 in the column direction). Each pixel electrode 112 is connected to the drain terminal of the TFT 111.

  The gate terminal of the TFT 111 is connected to the gate line 114, and the source terminal of the TFT 111 is connected to the source line 113. Each of the gate lines 114 is connected to a voltage output unit in the gate driver 24, and each of the source lines 113 is connected to a voltage output unit in the source driver 23.

  The TFT 111 is controlled to be turned on / off by sequentially applying a voltage from the gate driver 24 to the gate line 114. During the on period, the TFT 111 applies a voltage input from the source driver 23 to each source line 113 to the pixel electrode 112. The voltage until then is maintained during the off period. Then, the light transmittance determined by the optical characteristics (TV characteristics) of the liquid crystal substance is controlled by the voltage applied to the pixel electrode 112 via the TFT 111 and the voltage applied to the common electrode 121, and the image Is displayed. The liquid crystal panel 1 in Embodiment 1 is configured to have a light transmittance of zero when the potential difference between the pixel electrode 112 and the common electrode 121 is zero. That is, the liquid crystal panel 1 is a so-called normally black liquid crystal panel configured to perform black display when no potential difference is generated between the array substrate 11 and the CF substrate 12. Note that the TFT 111 corresponds to a switching element, and the source line 113 corresponds to a signal line.

FIG. 3 is a diagram illustrating an equivalent circuit of each pixel. The liquid crystal element in each pixel can be expressed as a liquid crystal capacitor 115 connected to the TFT 111. As described above, the gate terminal of the TFT 111 is connected to the gate line 114, and the source terminal of the TFT 111 is connected to the source line 113. When a voltage exceeding the voltage of the source line 113 is applied to the gate line 114, the TFT 111 is turned on, the voltage of the source line 113 is applied to the pixel electrode 112 via the TFT 111, and charges are stored in the liquid crystal capacitor 115. In the first embodiment, the storage capacitor 116 connected in parallel to the liquid crystal capacitor 115 is provided, and when the voltage is applied to the pixel electrode 112, the storage capacitor 116 is also charged. Then, while no voltage is applied from the outside, the voltage value of the liquid crystal element is maintained by the potential held by the storage capacitor 116.

  In the display device 100 configured as described above, the display driving device 2 displays a frame image on the liquid crystal panel 1 at a predetermined frame rate based on the input image signal. That is, if the input image signal represents a still image, one frame image is displayed on the liquid crystal panel 1 for each frame, and if the image signal represents a moving image, a different frame image for each frame. Is displayed on the liquid crystal panel 1. Further, the display driving device 2 provides a blanking period between the frames. The blanking period is a period in which all TFTs 111 provided in the liquid crystal panel 1 are in an off state. That is, the display device 100 is configured to periodically provide a blanking period. In the first embodiment, the display driving device 2 applies a voltage to the source line 113 during a part of the blanking period. Hereinafter, a voltage application mode in the display driving device 2 will be described.

  FIG. 4 is an explanatory diagram for explaining the timing at which the display driving device 2 applies a voltage to the source line 113. FIG. 4A shows the timing of applying a voltage to each source line 113 connected to the source driver 23, and “Yes” on the vertical axis indicates that a voltage is applied to each source line 113. “None” indicates that no voltage is applied to each source line 113. FIG. 4B schematically shows the transition of the current flowing from the source power supply circuit 31 to the source driver 23, and the vertical axis indicates the current value. FIG. 4C schematically shows the transition of the output voltage of the source power supply circuit 31, and the vertical axis indicates the voltage value. The horizontal axes of FIGS. 4A, 4B, and 4C indicate time. In FIG. 4, a period of one frame is referred to as a frame period, and a period other than the blanking period in the frame period is referred to as a display period.

  During the display period, the display driving device 2 sequentially applies a voltage for turning on the TFT 111 to the connected gate line 114, and the gradation at the corresponding position of the frame image is applied to the TFT 111 connected to the applied gate line 114. Is sequentially applied to each source line 113. Therefore, in the “present” period of the display period in FIG. 4A, each source line is applied in order to apply a voltage representing the gradation of the corresponding position of the frame image to each TFT 111 connected to one gate line 114. 113 indicates that the voltage is applied. Further, the display driving device 2 during the blanking period applies a voltage representing white gradation to each source line 113 only once during a part of the blanking period T1. The end point of time T1 is within a predetermined time interval before the end of the blanking period. The predetermined time interval is, for example, several microseconds, and the remaining time of the blanking period is the time over substantially the entire blanking period. That is, the time T1 in the first embodiment is a minimum time during which a voltage can be applied to each source line 113 only once.

  The current value shown during the display period shown in FIG. 4B is the pixel electrode 112 and common electrode of each TFT 111 connected to one gate line 114 each time the display driving device 2 applies a voltage to each source line 113. A total of current values flowing between 121 is shown. Further, the current value shown during the blanking period shown in FIG. 4B is the sum of the current values flowing through the source lines 113 when a voltage representing white gradation is applied to the source lines 113. It is shown. At this time, a current flows through each source line 113 due to the charge being stored in the stray capacitance existing in each source line 113.

  Here, in the liquid crystal panel 1, stray capacitances exist between the source line 113 and the gate line 114 between the other source line 113, the gate line 114, the pixel electrode 112, the common electrode 121, and the like. During the display period, the source driver 23 repeatedly applies a voltage corresponding to the image display to each source line 113. Therefore, the charge is stored in the stray capacitance, and the current value that flows due to the stray capacitance is negligible with respect to the current value that flows between the pixel electrode 112 and the common electrode 121 for each source line 113. Few. On the other hand, during the blanking period, the charge stored in the stray capacitance is discharged due to the voltage not being applied to each source line 113 during the remaining time, and the stray capacitance newly stores the charge. It is possible to do. For this reason, when a relatively high voltage is applied to each source line 113, a relatively large current flows through each signal line due to an increase in the charge stored in the stray capacitance. Sometimes drops.

  The display driving device 2 according to the first embodiment applies the voltage representing white gradation, that is, the maximum voltage to each source line 113 during the blanking period before the display period arrives. The voltage can be reliably reduced. Even when the output voltage is lowered during the blanking period, the TFTs 111 are all in an off state, and thus display quality is not affected. Further, by reducing the output voltage in advance during the blanking period, as shown in FIG. 4C, the reduced voltage due to the response characteristics of the source power supply circuit 31 until the next display period starts. Can be raised.

On the other hand, when no voltage is applied during the blanking period and a voltage representing white gradation is applied at the beginning of the next display period, the output voltage decreases after the display period starts. When a relatively low voltage such as a voltage representing a black gradation is applied to each source line 113 during the blanking period, a voltage representing a white gradation is applied at the beginning of the next display period. Similarly, the output voltage drops after the display period starts. Therefore, the display device 100 according to the first embodiment can improve the display quality after the blanking period ends.
The end point of time T1 is within a predetermined time interval before the end of the blanking period, and substantially coincides with the end. Therefore, the display driving device 2 can apply a voltage corresponding to the display of the image to be displayed after the blanking period, without the stray capacitance in the source line 113 being discharged. For this reason, it is possible to more reliably suppress the deterioration in display quality after the blanking period due to the decrease in the output voltage of the source power supply circuit 31.
As described above, the display device 100 according to the first embodiment can suppress deterioration in display quality due to the stray capacitance of the source line 113. Note that the end point of T1 may be configured to coincide with the end of the blanking period.

  In the display device 100 according to the first embodiment, the display driving device 2 only applies the white voltage to the source line 113 only once within the time T1 during the blanking period. Therefore, over the blanking period, the display device 100 can reduce power consumption as compared to a display device that applies a voltage that represents a gray level such as black and has a potential difference with the common electrode 121 of zero. In the first embodiment, it has been described that the voltage applied during the blanking period represents a gray level of white, but any voltage that can decrease the output voltage of the source power supply circuit 31 may be used. For example, the display driving device 2 may apply a voltage representing a gray level on the white side of the halftone to each source line 113.

  Furthermore, as described above, the source line 113 of the liquid crystal panel 1 is applied to the liquid crystal panel 1 by applying a voltage whose potential difference with the common electrode 121 is greater than zero within a part of the blanking period T1. It is possible to suppress the deterioration of display quality due to. Note that the voltage whose potential difference is greater than zero may be a voltage that can reduce the output voltage of the source power supply circuit 31, and is, for example, a voltage that represents a gray level on the white side of the halftone.

(Embodiment 2)
In the display device 100 according to the first embodiment, the example in which the display driving device 2 applies a voltage representing white gradation to each source line 113 during the blanking period has been described. In the second embodiment, an example in which a voltage representing a gradation other than white is applied will be described. Since the other configurations and operations other than the configurations and operations described below are the same as those in the first embodiment, the same reference numerals are given to the same parts, and a detailed description of the same configurations and the descriptions thereof are given. Description of the function and effect is omitted.

  FIG. 5 is a block diagram illustrating a configuration of the display device 100 according to the second embodiment. In the second embodiment, the display driving device 2 includes a frame memory 25. The control unit 21 stores display data of an image to be displayed in units of frames in the frame memory 25 based on the input image signal. When displaying a frame image in each frame period, the control unit 21 reads the corresponding display data from the frame memory 25 and outputs it to the timing controller 22.

  FIG. 6 is an explanatory diagram for explaining the timing at which the display driving apparatus 2 applies a voltage to the source line 113. In the second embodiment, the display driving device 2 applies a voltage representing the same gray level as the beginning of the next display period to each source line 113 only once within the time T1. Specifically, the control unit 21 is connected to one gate line 114 to which a voltage for turning on the TFT 111 is first applied from display data to be displayed in the next display period from the frame memory 25. Data to be displayed at the corresponding position of the TFT 111 is read out. That is, the control unit 21 reads data of an image portion that is displayed first after the display period starts. Next, the control unit 21 outputs the read data to the timing controller 22. Thereafter, the source driver 23 applies a voltage representing the data to each source line 113 in accordance with a control signal from the timing controller 22.

  As described above, by applying a voltage applied to each source line 113 at the beginning of the display period after the blanking period, it is not necessary to separately set a voltage to be applied to the signal line during the blanking period. A decrease in display quality of the liquid crystal panel 1 can be suppressed.

(Embodiment 3)
In the display device 100 according to the first and second embodiments, the example in which the display driving device 2 applies a voltage to each source line 113 only once during the blanking period has been described. In the third embodiment, an example will be described in which the display driving device 2 applies a voltage to each source line 113 a plurality of times during the blanking period. Since the other configurations and operations other than the configurations and operations described below are the same as those in the first embodiment, the same reference numerals are given to the same parts, and the detailed description of the same configurations and the operations thereof are the same. Description of the effect is omitted.

  FIG. 7 is an explanatory diagram illustrating the timing at which the display driving device 2 according to the third embodiment applies a voltage to the source line 113. In the third embodiment, the display driving device 2 repeatedly applies a voltage representing white gradation to each source line 113 for a part of the time T2 during the blanking period. The end point of time T2 is within a predetermined time interval before the end of the blanking period. The remaining time of the blanking period is the time over substantially the entire blanking period. That is, the time T2 in the third embodiment is a minimum time during which a voltage can be applied to each source line 113 a plurality of times. For example, when the frame rate is 60 Hz, the number of times is about 4 to 6 times.

  As described above, the voltage representing the white gradation is repeatedly applied to each source line 113 over time T2, thereby reliably preventing the discharge of the charge accumulated in the stray capacitance of each source line 113. be able to. For this reason, in the display period after the blanking period, it is possible to more reliably suppress the deterioration in display quality caused by the decrease in the output voltage of the source power supply circuit 31.

(Embodiment 4)
In the display device 100 according to the third embodiment, the example in which the display driving device 2 applies a voltage representing white gradation to each source line 113 a plurality of times during the blanking period has been described. In the fourth embodiment, an example in which the voltage applied by the display driving device 2 represents a gradation other than white will be described. Since the other configurations and operations except the configurations and operations described below are the same as those in the above-described second and third embodiments, the same parts are denoted by the same reference numerals, and detailed description of the same configurations is given. Description of the function and effect thereof is omitted.

  FIG. 8 is an explanatory diagram illustrating the timing at which the display driving device 2 according to the fourth embodiment applies a voltage to the source line 113. In the fourth embodiment, the display driving device 2 repeatedly applies a voltage representing the same gray level as the beginning of the next display period to each source line 113 over time T2. As described above, the voltage representing the same gradation is repeatedly applied to each source line 113 over a part of the time T2 in the blanking period, thereby discharging the charge stored in the stray capacitance of each source line 113. Etc. can be reliably prevented. For this reason, in the display period after the blanking period, it is possible to more reliably suppress the deterioration in display quality caused by the decrease in the output voltage of the source power supply circuit 31. Further, the display device 100 can suppress power consumption during the blanking period as compared with a case where a voltage representing white gradation is repeatedly applied to each source line 113.

(Embodiment 5)
In the display devices 100 of the first to fourth embodiments, it has been described that the display driving device 2 does not apply a voltage to each source line 113 during the remaining time during the blanking period. It is good also as a structure to apply. At this time, if the applied voltage is a voltage lower than a voltage applied during a part of the time T1 or T2 during the blanking period, for example, a voltage representing black gradation, the charge stored in the stray capacitance Since there is little quantity, the same effect as Embodiments 1-4 can be acquired. Note that the number of times the voltage is applied in the remaining period may be one time or a plurality of times.

(Embodiment 6)
In the first to fifth embodiments, the example in which the display driving device 2 applies a voltage to each source line 113 during the blanking period when the liquid crystal panel 1 is a normally black type has been described. Normally white type may be used. At this time, the voltage applied in a part of the blanking period is a voltage representing a gradation obtained by inverting the gradation in the first to fifth embodiments, such as a gradation representing black. The effect similar to ~ 5 can be acquired.

(Embodiment 7)
In the display devices 100 of the first to sixth embodiments, the end point of a part of the time T1 or T2 in the blanking period is within a predetermined time interval before the end of the blanking period, and substantially coincides with the end. explained. In the display device 100, the end point of the time T1 or T2 may not substantially coincide with the end of the blanking period. For example, the start point and end point of the time T1 or T2 may be in the first half of the blanking period, the start point and end point may be in the first half and the second half of the blanking period, and the start point and end point are in the blanking period. It may be in the second half of.

  In addition, the display apparatus 100 demonstrated in Embodiment 1-7 is applicable by various uses. For example, a similar configuration can be applied to a display device that displays an image related to television broadcasting received by a tuner or the like. For example, the present invention can be applied to an operation screen of each electronic device.

  The display driving device (2) according to the present invention includes a common electrode (121), a plurality of pixel electrodes (112), a plurality of switching elements (111) connected to each pixel electrode (112), and the plurality of switching elements. A blanking period for periodically turning off all the switching elements (111) of the liquid crystal panel (1) formed by opposing the plurality of signal lines (113) connected to the elements (111) is provided. In the display driving device (2), a voltage for applying a predetermined voltage having a potential difference greater than zero with respect to the common electrode (121) to the signal line (113) within a part of the blanking period. An application unit (23) is provided.

  In the present invention, the display driving device (2) periodically provides a blanking period for turning off all the switching elements (111) provided in the liquid crystal panel (1). The voltage application unit (23) of the display driving device (2) applies a predetermined voltage with a potential difference greater than zero to the signal line (113) within a part of the blanking period with respect to the common electrode (121). To do. For example, when a voltage having a relatively large potential difference with the common electrode (121) is applied to the signal line (113) during the blanking period, the amount of charge stored in the stray capacitance of the signal line (113) is increased. A large current flows. Therefore, the display driving device (2) can reduce the output voltage of the power source (31) for applying a voltage to the signal line (113) during the blanking period. Even if the output voltage of the power source (31) decreases during the blanking period, there is no problem in display quality because the switching element (111) is off. In addition, when a voltage corresponding to an image to be displayed is applied after the blanking period, the charge is stored in the stray capacitance of the signal line (113) during the part of time, so the power source (31) The output voltage can be prevented from decreasing. Accordingly, it is possible to suppress a reduction in display quality due to the stray capacitance of the signal line (113) provided in the liquid crystal panel (1).

  The display driving apparatus (2) according to the present invention is characterized in that the end point of the partial time is within a predetermined time interval before the end of the blanking period.

  In the present invention, the end point of a part of time is within a predetermined time interval before the end of the blanking period. For example, when the predetermined time interval is short, the display driving device (2) can apply a voltage according to the display of the image to be displayed after the blanking period without causing the stray capacitance in the signal line to be discharged. it can. For this reason, it is possible to more reliably suppress the deterioration in display quality caused by the decrease in the output voltage of the power supply (31) having the voltage to be applied to the signal line (113).

  In the display driving device (2) according to the present invention, the voltage application unit (23) applies the predetermined voltage to each of the plurality of signal lines (113) only once within the partial time period. It is characterized by that.

  In the present invention, the voltage application unit (23) has a predetermined potential difference between the plurality of signal lines (113) and the common electrode (121) greater than zero within a part of the blanking period. Apply voltage only once. Therefore, the voltage applied to the signal line (113) can be minimized for the purpose of storing charges in the stray capacitance of each signal line (113). Therefore, it is possible to reduce power consumption during the blanking period while suppressing a decrease in display quality.

  In the display driving device (2) according to the present invention, the voltage application unit (23) repeatedly applies the predetermined voltage to each of the plurality of signal lines (113) for the part of time. It is characterized by that.

  In the present invention, the voltage application unit (23) repeatedly applies a predetermined voltage to each of the plurality of signal lines (113) over a part of the blanking period. Accordingly, the discharge of the charge stored in the stray capacitance of each signal line (113) can be reliably prevented, and the display resulting from the decrease in the output voltage of the voltage to be applied to the signal line (113). Degradation of quality can be more reliably suppressed.

  In the display driving device (2) according to the present invention, the voltage application unit (23) does not apply a voltage to the signal line (113) during the remaining time in the blanking period. And

  In the present invention, the voltage application unit (23) does not apply a voltage to the signal line (113) during the remaining period in the blanking period. Therefore, it is possible to further reduce power consumption during the blanking period while suppressing deterioration in display quality.

  A display device (100) according to the present invention includes a display drive device (2), a common electrode (121), a plurality of pixel electrodes (112), and a plurality of switching elements connected to each pixel electrode (112). (111) and a liquid crystal panel (1) formed by opposingly arranging a plurality of signal lines (113) connected to the plurality of switching elements (111), and the display driving device (2) includes: A voltage is applied to the signal line (113) of the liquid crystal panel (1).

  In the present invention, the display device (100) includes the display drive device (2) described above and the liquid crystal panel (1). The liquid crystal panel (1) includes a common electrode (121), a plurality of pixel electrodes (112), a plurality of switching elements (111) connected to the pixel electrodes (112), and the plurality of switching elements (111). A plurality of connected signal lines (113) are arranged to face each other. The display driving device (2) applies a voltage to the signal line (113) of the liquid crystal panel (1). Therefore, the display device (100) can suppress a decrease in display quality due to the stray capacitance of the signal line (113) provided in the liquid crystal panel (1).

  The display device (100) according to the present invention is configured such that the liquid crystal panel (1) performs black display when no potential difference is generated between the common electrode (121) and the pixel electrode (112). The voltage application unit (23) applies a voltage representing a gray level on the white side of the halftone as the predetermined voltage to the signal line within the part of the time. And

  In the present invention, the liquid crystal panel (1) is a so-called normally black system that performs black display when no potential difference is generated between the common electrode (121) and the pixel electrode (112). The voltage application unit (23) applies a voltage representing a gray level on the white side of the halftone to the signal line (113) as the predetermined voltage. In the normally black liquid crystal panel (1), the voltage to be applied to the signal line (113) increases as the gradation level to be displayed increases. Accordingly, the voltage application unit (23) can apply the voltage representing the gray level on the white side of the halftone to the signal line (113) during the blanking period, thereby reducing the output voltage of the power source (31). it can. Accordingly, it is possible to suppress a decrease in display quality.

  In the display device (100) according to the present invention, the voltage application unit (23) applies a voltage representing white gradation as the predetermined voltage to the signal line (113) within the part of the time. It is made to do so.

  In the present invention, the voltage application unit (23) applies a voltage representing white gradation to the signal line (113) as the predetermined voltage. In the normally black liquid crystal panel (1), the voltage representing the white gradation is the maximum voltage, so that the output voltage of the power supply can be reliably lowered during the blanking period. Therefore, it is possible to reliably suppress the display quality from deteriorating.

  In the display device (100) according to the present invention, the display driving device (2) applies a voltage corresponding to display of an image to be displayed on the liquid crystal panel (1) during the blanking period to the signal line. (113), and the voltage application unit (23) uses the voltage initially applied to the signal line (113) as the predetermined voltage after the blanking period ends as the predetermined voltage. ) Is applied.

  In the present invention, the display driving device (2) applies a voltage corresponding to display of an image to be displayed on the liquid crystal panel (1) to the signal line (113) at the end of the blanking period. The voltage applying unit applies the voltage first applied to the signal line (113) to the signal line (113) in the blanking period after the blanking period ends. Therefore, the display driving device (2) does not separately set a voltage to be applied to the signal line during the blanking period, and displays due to the stray capacitance of the signal line (113) provided in the liquid crystal panel (1). Degradation can be suppressed.

  The display driving method according to the present invention includes a common electrode (121), a plurality of pixel electrodes (112), a plurality of switching elements (111) connected to each pixel electrode (112), and the plurality of switching elements (111). A blanking period for periodically turning off all the switching elements (111) of the liquid crystal panel (1) formed by opposing a plurality of signal lines (113) connected to the display is provided. In the driving method, a predetermined voltage having a potential difference greater than zero with respect to the common electrode (121) is applied to the signal line (113) within a part of the blanking period.

  In the present invention, a blanking period for periodically turning off all the switching elements (111) provided in the liquid crystal panel (1) is provided. In addition, a predetermined voltage whose potential difference from the common electrode (121) is larger than zero is applied to the signal line (113) provided in the liquid crystal panel (1) within a part of the blanking period. For example, when a voltage having a relatively large potential difference with the common electrode (121) is applied to the signal line (113) during the blanking period, the amount of charge stored in the stray capacitance of the signal line (113) is increased. A large current flows. Therefore, the display driving device (2) can reduce the output voltage of the power source (31) for applying a voltage to the signal line (113) during the blanking period. Even if the output voltage of the power source (31) decreases during the blanking period, there is no problem in display quality because the switching element (111) is off. In addition, when a voltage corresponding to an image to be displayed is applied after the blanking period, the charge is stored in the stray capacitance of the signal line (113) during the part of time, so the power source (31) The output voltage can be prevented from decreasing. Accordingly, it is possible to suppress a reduction in display quality due to the stray capacitance of the signal line (113) provided in the liquid crystal panel (1).

  Furthermore, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of claims for patent, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims for patent.

DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Display drive device 3 Drive power supply part 11 Array board | substrate 12 CF board | substrate 21 Control part 22 Timing controller 23 Source driver (voltage application part)
24 Gate Driver 25 Frame Memory 31 Source Power Supply Circuit 32 Gate Power Supply Circuit 100 Display Device 111 TFT (Switching Element)
112 pixel electrode 113 source line (signal line)
114 Gate line 121 Common electrode

Claims (12)

All of the switching elements of the liquid crystal panel in which a common electrode, a plurality of pixel electrodes, a plurality of switching elements connected to each pixel electrode, and a plurality of signal lines connected to the plurality of switching elements are arranged to face each other. In a display drive device that is configured to periodically provide a blanking period for turning off,
A voltage application unit that applies a predetermined voltage having a potential difference with respect to the common electrode greater than zero within a part of the blanking period to the signal line;
The voltage applying unit repeatedly applies a voltage to each of the plurality of signal lines within a series of periods including the part of time and a display period excluding the blanking period. Drive device. The voltage application unit maintains the continuity of the period in which the voltage is applied to each of the plurality of signal lines within the part of the time and the display period excluding the blanking period thereafter. The display driving device according to claim 1 , wherein a voltage is applied. The display drive device according to claim 1, wherein the voltage application unit is configured not to apply a voltage to the signal line during the remaining time in the blanking period. 2. The charge stored in the stray capacitance in the signal line is discharged due to no voltage being applied to the signal line in the remaining time in the blanking period. 4. The display driving device according to any one of items 1 to 3. The end point of the part of time is within a predetermined time interval before the end of the blanking period or coincides with the end of the blanking period. The display drive device described in 1. The said voltage application part applies the said predetermined voltage to each of these signal lines only once within the said one part time, The Claim 1 characterized by the above-mentioned. Display drive device. The voltage application unit is configured to repeatedly apply the predetermined voltage to each of the plurality of signal lines over the part of the time. The display drive device described in 1. A display driving device according to any one of claims 1 to 7,
A common electrode, a plurality of pixel electrodes, a plurality of switching elements connected to each pixel electrode, and a liquid crystal panel formed by opposingly arranging a plurality of signal lines connected to the plurality of switching elements,
The display drive device is configured to apply a voltage to a signal line of the liquid crystal panel. The liquid crystal panel is configured to perform black display when no potential difference is generated between the common electrode and the pixel electrode,
The voltage application unit is configured to apply, to the signal line, a voltage representing a gray level on the white side of a halftone as the predetermined voltage within the part of the time. 9. The display device according to 8. 10. The display according to claim 9, wherein the voltage application unit applies a voltage representing white gradation as the predetermined voltage to the signal line within the part of the time. apparatus. The display driving device is configured to apply a voltage according to display of an image to be displayed on the liquid crystal panel to the signal line during the blanking period.
The display according to claim 8, wherein the voltage application unit is configured to apply the voltage first applied to the signal line to the signal line as the predetermined voltage after the blanking period ends. apparatus. All of the switching elements of the liquid crystal panel in which a common electrode, a plurality of pixel electrodes, a plurality of switching elements connected to each pixel electrode, and a plurality of signal lines connected to the plurality of switching elements are arranged to face each other. In a display driving method in which blanking periods for turning off are periodically provided,
A predetermined voltage having a potential difference with the common electrode larger than zero is applied to the signal line within a part of the blanking period,
A display driving method, wherein a voltage is repeatedly applied to each of the plurality of signal lines within a series of periods including the partial time and a display period excluding the blanking period.

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