JP2015141315A - Drive circuit, display device, and driving method of display device - Google Patents

Drive circuit, display device, and driving method of display device Download PDF

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JP2015141315A
JP2015141315A JP2014014117A JP2014014117A JP2015141315A JP 2015141315 A JP2015141315 A JP 2015141315A JP 2014014117 A JP2014014117 A JP 2014014117A JP 2014014117 A JP2014014117 A JP 2014014117A JP 2015141315 A JP2015141315 A JP 2015141315A
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row group
pixel row
driving
pixel
tft
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善道 高野
Yoshimichi Takano
善道 高野
啓二 石井
Keiji Ishii
啓二 石井
佐藤 弘人
Hiroto Sato
弘人 佐藤
武順 薄井
Takemasa Usui
武順 薄井
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日本放送協会
Nippon Hoso Kyokai <Nhk>
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Abstract

Provided are a driving circuit, a display device, and a driving method of the display device that enable continuous display in an organic EL display.
A drive circuit simultaneously corrects a threshold voltage of a driving TFT in a first pixel row group that is continuous in a column direction among a plurality of pixel rows, and corrects a threshold voltage of the driving TFT in the first pixel row group. Later, the signal potentials of the first pixel row group are sequentially sampled. When the first standby period elapses from the end of the sampling of the first pixel row group, the driving TFTs of the first pixel row group are sequentially turned on, and the first When the sampling for the pixel row group is completed, the threshold voltage of the driving TFT in the second pixel row group that is continuous with the first pixel row group is simultaneously corrected, and after the threshold voltage of the driving TFT in the second pixel row group is corrected. The signal potentials of the respective rows of the second pixel row group are sequentially sampled, and when the second standby period elapses from the end of the sampling for the second pixel row group, the second pixel row is continuous with the first pixel row group. The group of driving TFTs is turned on sequentially. To.
[Selection] Figure 3

Description

  The present invention relates to a drive circuit for driving an organic EL (Electro Luminescence) display in an active matrix.

  Conventionally, there is a display device including a pixel array unit and a driving unit that drives the pixel array unit. The pixel array section includes a row-shaped scanning line, a column-shaped signal line, a matrix-shaped pixel arranged at a portion where both intersect, and a power supply line arranged corresponding to each row of each pixel. The driving unit includes a main scanner (write scanner) that scans pixels line by line, a power supply scanner that supplies a power supply voltage to each power supply line in accordance with the line sequential scan, and a signal line in accordance with the line sequential scan. Includes a horizontal selector that supplies a signal potential and a reference potential (see, for example, Patent Document 1).

  In addition, there is a display device in which a threshold voltage correction operation is repeatedly performed in a plurality of horizontal periods preceding signal potential sampling to hold a voltage corresponding to the threshold voltage of a driving transistor in a holding capacitor. In this display device, writing of a voltage corresponding to the threshold voltage is repeatedly performed in a plurality of times to ensure a sufficient writing time (see, for example, Patent Document 2).

In addition, there is a display device that prevents potential leakage by binarizing a reference potential of a video signal to make a sampling transistor out of pass when performing a threshold voltage correction operation (see, for example, Patent Document 3).
In addition, there is a display device in which a plurality of horizontal lines are set as one unit and threshold correction operations are simultaneously performed in each pixel circuit in the same unit (for example, see Patent Document 4).

JP 2007-310311 A JP 2008-033193 JP 2009-163146 A JP 2010-002498 A

  With the technique of Patent Document 1, it is possible to correct characteristic variations such as threshold voltage and mobility of a driving transistor with a relatively simple pixel circuit configuration. Further, the techniques of Patent Documents 2 and 3 are used for the purpose of sufficiently securing a voltage writing time corresponding to the threshold voltage in order to perform sufficient correction.

  However, in the techniques described in Patent Documents 2 and 3, since the signal potential sampling and the threshold voltage correction operation must be performed within the scanning time of one line of the screen, it is difficult to shorten the scanning time of one line. . In order to increase the number of lines on the screen as the resolution of the organic EL display increases, it is necessary to shorten the scanning time for each line. However, in the driving methods of Patent Documents 2 and 3, the scanning time is shortened. It was difficult to do.

  In this regard, in the technique described in Patent Document 4, since the threshold value correcting operation is simultaneously performed in each pixel circuit in one unit including a plurality of horizontal lines, the scanning time is shortened. There is a possibility that the display becomes discontinuous at the boundary.

  Accordingly, it is an object of the present invention to provide a driving circuit, a display device, and a driving method of the display device that can realize continuous display in an organic EL display.

  In the driving circuit according to the embodiment of the present invention, a source is connected to an anode of an organic EL element, a drain is connected to a power supply line, a driving TFT for driving the organic EL element, and one of the drain or source is a data line Each pixel includes a selection TFT whose drain or source is connected to the gate of the driving TFT and a storage capacitor connected between the source and gate of the driving TFT. And simultaneously correcting the threshold voltage of the driving TFT of the first pixel row group in the column direction of the pixel rows, and after correcting the threshold voltage of the driving TFT of the first pixel row group, The signal potentials of each row of one pixel row group are sequentially sampled, and when a first standby period elapses from the end of the sampling for the first pixel row group, the driving TFT of the first pixel row group When the sampling for the first pixel row group is completed, the threshold voltages of the driving TFTs in the second pixel row group that are continuous to the first pixel row group are corrected simultaneously, and the second pixel row After correcting the threshold voltage of the driving TFT of the group, sampling of the signal potential of each row of the second pixel row group is sequentially performed, and from the end of the sampling for the second pixel row group, the first waiting period and When a different second standby period elapses, the driving TFTs in the second pixel row group are sequentially turned on so as to be continuous with the driving TFTs in the first pixel row group.

  It is possible to provide a driving circuit, a display device, and a display device driving method that enable continuous display in an organic EL display.

1 is a diagram showing a display device 100 according to Embodiment 1. FIG. 2 is a diagram illustrating an internal configuration of each pixel 111 of the organic EL display panel 110 according to Embodiment 1 and a connection relationship between a horizontal selector 120, a light scanner 130, and a power supply scanner 140. FIG. 3 is a timing chart illustrating a method for driving the display device 100 according to the first embodiment. 3 is a timing chart illustrating a method for driving the display device 100 according to the first embodiment. It is a timing chart which shows the drive method for a comparison. It is a timing chart which shows the drive method for a comparison. 6 is a timing chart showing a method for driving display device 100 according to a modification of the first embodiment. 10 is a diagram showing a method for driving a display device according to Embodiment 2. FIG.

  Embodiments to which the driving circuit, display device, and driving method of the display device of the present invention are applied will be described below.

<Embodiment 1>
FIG. 1 is a diagram illustrating a display device 100 according to the first embodiment.

  The display device 100 includes an organic EL display panel 110, a horizontal selector 120, a light scanner 130, and a power scanner 140.

  The organic EL display panel 110 includes a plurality of pixels (PXLC) 111 arranged in a matrix. For convenience of explanation, FIG. 1 includes six pixels 111, but actually includes, for example, 640 × 480 pixels when the organic EL display panel 110 is VGA standard.

  The horizontal selector 120 (HSEL) is a circuit that performs selection in the horizontal direction, and is connected to each pixel 111 via n data lines 121. As described above, when the organic EL display panel 110 is VGA standard, n is 640.

  The write scanner 130 (WSCN) is a circuit for selecting a plurality of pixel rows arranged in a matrix, and is connected to each pixel 111 via m selection lines 131. As described above, when the organic EL display panel 110 is VGA standard, m is 480.

  The power supply scanner 140 (DSCN) is a circuit that supplies power to each pixel 111 for causing the organic EL elements included in each pixel 111 to emit light. The power supply scanner 140 (DSCN) is connected to each pixel 111 via m power supply lines 141. Yes. The number of power supply lines 141 is equal to the number of selection lines 131.

  Next, the internal configuration of each pixel 111 and the connection relationship between the horizontal selector 120, the write scanner 130, and the power supply scanner 140 will be described with reference to FIG.

  FIG. 2 is a diagram illustrating an internal configuration of each pixel 111 of the organic EL display panel 110 according to the first embodiment and a connection relationship between the horizontal selector 120, the light scanner 130, and the power supply scanner 140.

  In the pixel 111 of the organic EL display panel 110 (see FIG. 1), a selection TFT 151, a driving TFT 152, a capacitor 153, and an organic EL element 154 are disposed. The selection TFT 151 and the driving TFT 152 are n-channel TFTs (Thin Film Transistors). The selection TFT 151, the driving TFT 152, and the capacitor 153, the horizontal selector 120, the write scanner 130, and the power supply scanner 140 (see FIG. 1) constitute the driving circuit of the first embodiment.

  The selection TFT 151 has a drain connected to the data line 121, a source connected to the gate of the driving TFT 152, a gate connected to the selection line 131, and is driven by the write scanner 130. The selection TFT 151 performs row selection of a plurality of pixels 111 (see FIG. 1) arranged in a matrix. Note that the connection between the drain and the source of the selection TFT 151 may be reversed.

  The driving TFT 152 has a source connected to the anode of the organic EL element 154, a drain connected to the power supply line 141, and a gate connected to the source of the selection TFT 151. The driving TFT 152 is provided to drive the organic EL element 154.

  The capacitor 153 is connected between the gate and source of the driving TFT 152 and is provided to hold the threshold voltage Vth of the driving TFT 152. When the threshold voltages of the driving TFTs 152 included in the plurality of pixels 111 arranged in a matrix form vary, the threshold voltages Vth of the driving TFTs 152 are held in the corresponding capacitors 153, whereby the thresholds of the driving TFTs 152 are stored. Compensation of the voltage Vth is performed. The capacitor 153 is an example of a storage capacitor.

  The organic EL element 154 has an anode connected to the source of the driving TFT 152 and a cathode grounded.

  Next, a driving method for driving the organic EL display panel 110 of the display device 100 according to the first embodiment will be described with reference to FIGS. 3 and 4.

  3 and 4 are timing charts showing a driving method of the display device 100 according to the first embodiment.

  In FIG. 3, the horizontal axis represents the time axis, and the drive contents for each frame are shown. The vertical axis indicates the row direction of the pixel 111 (see FIG. 1). The row direction of the pixels 111 is the vertical direction in the organic EL display panel 110 shown in FIG. The selection of rows is performed sequentially from the upper side to the lower side. In FIG. 3, n pixel rows from the first row to the n-th row are divided into a pixel row group 1 from the first row to the n / 2 row, and (n / 2) +1 row to n. A driving method for driving the pixel row group 2 up to the first row will be described. The pixel row group 1 and the pixel row group 2 are examples of a first pixel row group and a second pixel row group, respectively.

  As shown in FIG. 3, in the first frame, the thresholds of all the driving TFTs 152 included in the pixel row group 1 from the first row to the n / 2th row from the time T0 to the time T1 (period shown by hatching). Voltage correction is performed simultaneously. A period in which the threshold voltage of the driving TFT 152 is corrected simultaneously is referred to as a correction period. During the correction period from time T0 to time T1, the threshold voltages of all the driving TFTs 152 included in the pixel row group 1 from the first row to the n / 2th row are simultaneously corrected.

  Further, when the correction period for the pixel row group 1 ends at time T1, sampling of the signal potential is sequentially performed row by row from time T1 according to the system clock of the display device 100. Sampling of the signal potential is performed one row at a time of the system clock, and is performed from the start of sampling of the first row at time T1 until the end of sampling of the n / 2th row at time T3. In FIG. 3, the sampling of the signal potential for the pixel row group 1 from the first row to the n / 2th row is indicated by a thick diagonal solid line. Here, the period indicated by the width of the oblique thick solid line is referred to as a sampling period.

  Further, at time T2 when the sampling period has elapsed from time T1 and when the standby period has elapsed, the organic EL elements 154 included in the pixels 111 in the first row emit light. The light emission of the organic EL element 154 is performed for a predetermined period indicated by a horizontal line in FIG. 3, and the light emission of the organic EL element 154 included in the pixel 111 in the first row elapses for a predetermined period indicated by the horizontal line from time T2. Done until the time. Thereafter, light is emitted one row at each system clock period, and the organic EL elements 154 included in the pixels 111 in the n / 2-th row are emitted at time T5. Light emission of the organic EL elements 154 included in the pixels 111 in the n / 2th row is performed from time T5 until a predetermined period indicated by a horizontal line elapses. The waiting period for each row has a length equal to the correction period for the pixel row group 1. This standby period is an example of a first standby time.

  In FIG. 3, the standby period for each row from the first row to the n / 2th row is shown as a slanted white strip period, and the organic EL elements 154 in each row from the first row to the n / 2th row emit light. The light emission period is shown as a horizontal line period.

  When the sampling of the n / 2th row is completed at the time T3, the pixel row group 2 from the (n / 2) + 1th row to the nth row is included in the pixel row group 2 from the time T3 to the time T4. The threshold voltages of all the driving TFTs 152 are corrected simultaneously. During the correction period from time T3 to time T4, the threshold voltages of all the driving TFTs 152 included in the pixel row group 2 from the (n / 2) + 1-th row to the n-th row are simultaneously corrected. Note that the correction period for the pixel row group 2 is equal to the correction period for the pixel row group 1.

  When the correction period for the pixel row group 2 ends at time T4, sampling of the signal potential is sequentially performed row by row from time T4 according to the system clock of the display device 100. The sampling of the signal potential is performed one row at every cycle of the system clock, and sampling of the (n / 2) + 1th row is started at time T4 until sampling of the nth row is completed at time T6. Done.

  Further, at the time when one cycle of the system clock has elapsed from time T5, the organic EL element 154 included in the pixel 111 in the (n / 2) +1 row is emitted, and thereafter, every cycle of the system clock. Light is emitted row by row, and the organic EL element 154 included in the pixel 111 in the nth row emits light at time T6. Here, no waiting period is provided for the pixel row group 2. That is, the waiting period is zero.

  Then, the operation of the second frame is started from time T6, and the same operation as that performed from time T0 to time T6 is repeated. The driving for the first frame from time T0 to time T6 is performed in the same manner for each frame after the second frame.

  Here, potentials of the data line 121, the selection line 131, and the power supply line 141 in the correction period, the sampling period, the standby period, and the light emission period will be described with reference to FIG. Times T0, T1, and T2 shown in FIG. 4 correspond to times T0, T1, and T2 shown in FIG.

  In FIG. 4, as an example, the data line 121 (1), the selection lines 131 (1), 131 (2), 131 (n / 2 + 1), 131 (n / 2 + 2), and the power supply lines 141 (1), 141 are shown. Each potential of (2), 141 (n / 2 + 1), 141 (n / 2 + 2) is shown.

  The data line 121 (1) is a data line located on the leftmost side among the plurality (m) of data lines 121 shown in FIG. That is, the data line 121 (1) is a data line with m = 1.

  The selection line 131 (1) and the power supply line 141 (1) are the selection line located on the uppermost (first row) of the plurality (n) of selection lines 131 and the power supply lines 141 shown in FIG. Power line. That is, the selection line 131 (1) and the power supply line 141 (1) are selection lines and power supply lines where n is 1.

  The selection line 131 (2) and the power supply line 141 (2) are a selection line and a power supply line located in the second row, and n is a selection line and a power supply line with 2.

  The selection line 131 (n / 2 + 1) and the power supply line 141 (n / 2 + 1) are a selection line and a power supply line located in the (n / 2 + 1) th row. In other words, the selection line 131 (n / 2 + 1) and the power supply line 141 (n / 2 + 1) are the uppermost of the plural (n / 2) selection lines 131 and power supply lines 141 included in the pixel row group 2. A selection line and a power supply line.

  Similarly, the selection line 131 (n / 2 + 2) and the power supply line 141 (n / 2 + 2) are a selection line and a power supply line located in the (n / 2 + 2) row.

  As shown in FIG. 4, at time T0, the potential of the data line 121 (1) is at the L (Low) level. The L level of the data line 121 (1) is set to a predetermined potential that is slightly higher than the threshold voltage Vth of the driving TFT 152.

  At time T0, the potentials of the selection lines 131 (1) and 131 (2) rise from the L level to the H (High) level. When the potentials of the selection lines 131 (1) and 131 (2) become H level, the selection TFTs 151 included in the first and second pixel rows are turned on, and the L level of the data line 121 (1) is turned on. The driving TFT 152 is turned on by the potential.

  The operation as described above at the time T0 is the same for all the selection lines 131 included in the pixel row group 1. At the time T0, the selection TFT 151 included in the pixel row group 1 is turned on, so that The TFT 152 is turned on.

  At time T0, the potentials of the selection lines 131 (n / 2 + 1) and 131 (n / 2 + 2) included in the pixel row group 2 are held at the L level. This is the same for all the selection lines 131 included in the pixel row group 2.

  When the power supply lines 141 (1) and 141 (2) rise to H level at a time T01 when a certain time has elapsed from the time T0, a current flows between the drain and source of the driving TFT 152 in the pixel row group 1, and the capacitor 153 is charged.

  When the potentials of the selection lines 131 (1) and 131 (2) return to the L level at time T1, the selection TFT 151 is turned off, and the driving TFT 152 in the pixel row group 1 has a gate-source voltage. It turns off when the voltage drops to the threshold voltage Vth. Thereby, the correction of the threshold voltage of the driving TFT 152 of the pixel row group 1 is completed.

  Next, the signal potential of the data line 121 (1) changes according to the video signal every one cycle of the system clock from time T11 when a certain time has elapsed from time T1.

  When the selection line 131 (1) becomes H level at time T11, the selection TFT 151 in the first row is turned on, and the video signal is sampled in the capacitor 153 in the first row.

  Next, at time T12 when the time corresponding to one cycle of the system clock has elapsed from time T11, the signal potential of the data line 121 (1) changes, and the selection line 131 (2) becomes H level. The selection TFT 151 is turned on, and the video signal is sampled on the capacitor 153 in the second row.

  Thereafter, the video signals are sequentially sampled in the capacitors 153 from the third row to the n / 2th row for each cycle of the system clock. This corresponds to the sampling period indicated by the thick solid line in FIG.

  Further, regarding the power supply line 141 (1), the potential is held at the L level during the standby period (1) from the time T12 when the sampling ends to the time T2. Further, regarding the power supply line 141 (2), the potential is held at the L level during the standby period (2) from the time T13 when the sampling ends. Hereinafter, similarly, a standby period is provided from the third row to the n / 2th row at a timing shifted by one cycle of the system clock, and the potential of the power supply line 141 is held at the L level. This corresponds to the diagonal white belt-shaped waiting period in FIG.

  For the power supply line 141 (1), the potential of the power supply line 141 (1) becomes H level from time T2 when the standby period (1) ends, and light emission is performed over a predetermined period in FIG. Hereinafter, similarly, light emission is performed from the second row to the n / 2th row at a timing shifted by one cycle of the system clock. Light emission in each row is performed over the same period (predetermined period). This corresponds to the light emission period indicated by a horizontal line after time T2 in FIG.

  Further, a correction period for the pixel row group 2 is performed from time T3 to time T4, and thereafter, driving in the sampling period and the light emission period is similarly performed according to the drive pattern excluding the standby period from the pixel row group 1. Is done.

  As described above, in the display device 100 according to the first embodiment, n pixel rows from the first row to the n-th row are defined as the pixel row group 1 from the first row to the n / 2-th row, and (n / 2). The standby period provided between the signal potential sampling and the light emission for each row of the pixel row group 1 is divided into the pixel row group 2 from the + 1st row to the nth row, and is equal to the correction period for the pixel row group 1 That's it.

  Therefore, the organic EL elements 154 included in the pixels 111 in the first row are lit at time T2 when the standby period has elapsed from time T1, and thereafter, light is emitted one row at each system clock period. At T5, the organic EL element 154 included in the pixels 111 in the n / 2-th row emits light.

  Then, at the time when one cycle of the system clock has elapsed from time T5, the organic EL elements 154 included in the pixels 111 in the (n / 2) +1 row are emitted, and thereafter, one row for each cycle of the system clock. Light is emitted each time, and the organic EL element 154 included in the pixel 111 in the n-th row emits light at time T6.

  Therefore, the threshold voltages of all the driving TFTs 152 included in the pixel row group 1 and the pixel row group 2 can be simultaneously corrected, and the organic EL elements 154 in the n pixel rows from the first row to the nth row. Can be continuously emitted for each cycle of the system clock.

  Therefore, it is possible to provide the display device 100 that enables continuous display. In particular, at the boundary between the pixel row group 1 and the pixel row group 2, as with the light emission of each row in each of the pixel row group 1 and the pixel row group 2, it is continuously performed with a time difference corresponding to one cycle of the system clock. Since it can emit light, it is possible to suppress the appearance of discontinuous borders on the top and bottom of moving images and the appearance of discontinuous borders on the top and bottom of the still image due to the movement of the line of sight. A beautiful display can be realized. Such a driving method is particularly effective when displaying a moving image or a video with a large contrast difference.

  In addition, according to the first embodiment, it is possible to provide a drive circuit and a display device drive method that enable continuous display on an organic EL display.

  Further, since scanning (selection) of each row only samples the signal potential, the scanning time of each row can be shortened to the time required for sampling the signal potential.

  Further, by using the driving method as described above, it is possible to cope with the increase in the number of rows as the resolution of the organic EL display panel 110 increases.

  Further, the threshold voltage is corrected together at a timing different from the sampling of the signal potential of each row, so that a sufficient time can be secured and the voltage equivalent to the threshold voltage can be written reliably. .

  In the above description, an n-channel TFT is used as the selection TFT 151 and the driving TFT 152. However, when a p-channel TFT is used, a standby period may be similarly provided.

  Here, a driving method for comparison will be described with reference to FIGS. The organic EL element needs a certain light emission time rate in order to obtain a certain light emission luminance, and this time rate is assumed to be about 40%. However, the threshold voltage cannot be corrected simultaneously with the sampling of the signal potential and the light emission operation. For this reason, if the standby period is not provided, the following driving method is used.

  5 and 6 are timing charts showing a driving method for comparison.

  FIGS. 5 and 6 show a comparison driving method for driving the display device 100 having the configuration of FIGS. 1 and 2. The comparison driving method removes the standby period from the pixel row group 1, and Similarly to the pixel row group 2, the row group 1 is a driving method in which the light emission period is continuously provided after the sampling period.

  In FIG. 5, as in FIG. 3, the correction period is indicated by diagonal lines, the sampling period is indicated by thick diagonal solid lines, and the light emission period is indicated by horizontal lines. In FIG. 5, since no waiting period is provided for the pixel row group 1, there is a time lag between the light emission period of the pixel row group 1 and the light emission period of the pixel row group 2.

  Further, as shown in FIG. 6, after the potential of the power supply line 141 (1) becomes H level during the correction period for the pixel row group 1, there is no standby period, so that the light emission period (1) is unchanged. It is held at the H level until the end.

  Similarly, since the standby period does not exist after the potential of the power supply line 141 (2) becomes H level during the correction period for the pixel row group 1, it remains at H level until the end of the light emission period (2). Is retained. The end of the light emission period (2) is a time later than the end of the light emission period (1) by one cycle of the system clock.

  As described above, when the standby period is not provided, as shown in FIG. 5, there is a time lag between the light emission period of the pixel row group 1 and the light emission period of the pixel row group 2. When an image with a large contrast difference is displayed, discontinuous points occur in the image, and the image quality may deteriorate.

  On the other hand, the display device 100 according to the first embodiment can emit light continuously even at the boundary between the pixel row group 1 and the pixel row group 2, so that when displaying a moving image or a video with a large contrast difference. In addition, a beautiful and beautiful display can be realized.

  Although the pixel rows are divided into the pixel row group 1 and the pixel row group 2 in the above, for example, the write scanner 130 and / or the power scanner 140 is configured by an IC divided into two equal parts in the row direction. If so, the pixel rows may be divided for each IC.

  Note that, as described above, the period from the end of the correction period to the start of the sampling period is different for each row. In the case where there is a possibility that the display may be affected due to such a difference in period, the driving method shown in FIG. 4 may be modified as the driving method shown in FIG.

  FIG. 7 is a timing chart showing a method for driving display device 100 according to a modification of the first embodiment. The timing chart shown in FIG. 7 shows the timing of selection lines 131 (1), 131 (2),..., 131 (n / 2 + 1), 131 (n / 2 + 2). Partly different from the chart.

  In FIG. 7, for the pixel row group 1, after the potentials of the selection lines 131 (1), 131 (2),... Are raised to H level at time T0, the correction period ends more constant than time T1. At time T02 just before the time, the potentials of the selection lines 131 (1), 131 (2),... Are dropped to a predetermined negative potential Vn. The rest is the same as the driving method shown in FIG.

  As described above, by reducing the potential of the selection lines 131 (1), 131 (2),... To a negative potential at the end of the correction period, generation of a leakage current due to variations in the selection TFT 151 is suppressed. Can do.

  Therefore, when there is a possibility that the display may be affected due to a difference in period from the end of the correction period in each row to before the sampling period is started, the driving method shown in FIG. 7 may be used.

<Embodiment 2>
FIG. 8 is a diagram illustrating a method of driving the display device according to the second embodiment. In the driving method of the display device according to the second embodiment, n pixel rows from the first row to the n-th row are represented by a pixel row group 1 from the first row to the n / 4 row, (n / 4) +1. Pixel row group 2 from row to n / 2 row, pixel row group 3 from row (n / 2) +1 to 3n / 4, and row (3n / 4) +1 to row n In this method, the pixel row group 4 is divided into four equal parts. The pixel row group 1, the pixel row group 2, the pixel row group 3, and the pixel row group 4 are examples of the first pixel row group, the second pixel row group, the third pixel row group, and the fourth pixel row group, respectively. It is.

  Note that the configurations of the display device and the pixel are the same as those of the display device 100 (see FIG. 1) and the pixel 111 (see FIG. 2) of Embodiment 1, and thus redundant description is omitted.

  In FIG. 8, as in FIG. 3, the correction period is indicated by diagonal lines, the sampling period is indicated by diagonal thick solid lines, the standby period is indicated by diagonal white strips, and the light emission period is indicated by horizontal lines.

  As in the driving method of the first embodiment, in each pixel row group, the threshold voltage of the driving TFT 152 is corrected simultaneously. Note that the correction periods for the pixel row group 1, the pixel row group 2, the pixel row group 3, and the pixel row group 4 are all equal.

  Similarly to the driving method of the first embodiment, in each pixel row group, the sampling period is continuously shifted in a mode shifted by one cycle of the system clock as shown by the oblique solid line. To be done.

  Further, a waiting period is provided for the pixel row group 1, the pixel row group 2, and the pixel row group 3, and no waiting period is provided for the pixel row group 4. The driving for the pixel row group 4 is the same as the driving for the pixel row group 2 in the first embodiment.

  In the first embodiment, the standby period for the pixel row group 3 is equal to the correction period. The standby period for the pixel row group 2 is twice as long as the correction period. The standby period for the pixel row group 1 is three times the correction period. It can be understood that the waiting period for the pixel row group 4 is zero.

  With respect to the pixel row group 1, the pixel row group 2, and the pixel row group 3, the light emission of the pixel row group 1, the pixel row group 2, the pixel row group 3, and the pixel row group 4 is set if the standby period is set as described above. The period can be continuous.

  Therefore, according to the display device driving method of the second embodiment, it is possible to provide a display device driving method that enables continuous display. In addition, it is possible to prevent discontinuous borders from being seen up and down in moving images, and discontinuous borders from being seen up and down due to movement of the line of sight in still images, thereby realizing a beautiful and beautiful display. be able to. Such a driving method is particularly effective when displaying a moving image or a video with a large contrast difference.

  Further, it is effective to prevent the threshold voltage correction period and the light emission period from overlapping when the light emission time rate of the organic EL element is relatively long, for example, exceeding 50%.

  In addition, by using such a display device driving method, it is possible to provide a driving circuit and a display device that enable continuous display on an organic EL display.

  In the above description, a mode in which the pixel row is divided into four equal parts has been described. However, a standby period may be provided so that the pixel row is divided into an arbitrary number and the light emission period is continuous.

  The driving circuit, the display device, and the driving method of the display device according to the exemplary embodiments of the present invention have been described above. However, the present invention is not limited to the specifically disclosed embodiments, and may be patented. Various modifications and changes can be made without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 100 Display apparatus 110 Organic EL display panel 120 Horizontal selector 121 Data line 130 Write scanner 131 Selection line 140 Power supply scanner 141 Power supply line 151 Selection TFT
152 Driving TFT
153 Capacitor 154 Organic EL element

Claims (6)

  1. A source TFT connected to the anode of the organic EL element, a drain connected to the power line, and a driving TFT for driving the organic EL element;
    A selection TFT in which one of the drain and the source is connected to the data line and the other of the drain and the source is connected to the gate of the driving TFT;
    A storage capacitor connected between the source and gate of the driving TFT for each pixel,
    Correcting simultaneously the threshold voltage of the driving TFT of the first pixel row group that is continuous in the column direction among the plurality of pixel rows;
    After correcting the threshold voltage of the driving TFT of the first pixel row group, sampling of the signal potential of each row of the first pixel row group is sequentially performed,
    When the first standby period has elapsed since the end of the sampling for the first pixel row group, the driving TFTs of the first pixel row group are sequentially turned on,
    When the sampling for the first pixel row group is completed, the threshold voltages of the driving TFTs of the second pixel row group that are continuous with the first pixel row group are simultaneously corrected,
    After correcting the threshold voltage of the driving TFT of the second pixel row group, the signal potentials of each row of the second pixel row group are sequentially sampled,
    When a second standby period that is different from the first standby period has elapsed since the end of the sampling for the second pixel row group, the second pixel is continuous with the driving TFT of the first pixel row group. A driving circuit for sequentially turning on the driving TFTs in a row group.
  2.   The drive circuit according to claim 1, wherein a difference between the first standby period and the second standby time is equal to a time required for correcting the threshold voltage.
  3.   3. The drive circuit according to claim 1, wherein the second waiting time is zero when the second pixel row group is a pixel row group existing at the end in the column direction of the plurality of pixel rows. .
  4.   4. The drive circuit according to claim 1, wherein the first pixel row group and the second pixel row group correspond to a first IC and a second IC that drive the selection TFT. 5.
  5. A drive circuit according to any one of claims 1 to 4,
    A display device comprising: the organic EL element driven by the drive circuit.
  6. An organic EL element;
    A source TFT connected to the anode of the organic EL element, a drain connected to a power supply line, and a driving TFT for driving the organic EL element;
    A selection TFT in which one of the drain and the source is connected to the data line and the other of the drain and the source is connected to the gate of the driving TFT;
    A driving method of a display device including, for each pixel, a storage capacitor connected between a source and a gate of the driving TFT,
    Correcting simultaneously the threshold voltage of the driving TFT of the first pixel row group that is continuous in the column direction among the plurality of pixel rows;
    After correcting the threshold voltage of the driving TFT of the first pixel row group, sampling of the signal potential of each row of the first pixel row group is sequentially performed,
    When the first standby period has elapsed since the end of the sampling for the first pixel row group, the driving TFTs of the first pixel row group are sequentially turned on,
    When the sampling for the first pixel row group is completed, the threshold voltages of the driving TFTs of the second pixel row group that are continuous with the first pixel row group are simultaneously corrected,
    After correcting the threshold voltage of the driving TFT of the second pixel row group, the signal potentials of each row of the second pixel row group are sequentially sampled,
    When a second standby period that is different from the first standby period has elapsed since the end of the sampling for the second pixel row group, the second pixel is continuous with the driving TFT of the first pixel row group. A driving method of a display device, wherein the driving TFTs in a row group are sequentially turned on.
JP2014014117A 2014-01-29 2014-01-29 Drive circuit, display device, and driving method of display device Pending JP2015141315A (en)

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