The following disclosure relates to display devices and methods for driving the same, more specifically to a display device, such as an organic EL display device, which includes electro-optical elements driven by current, and also to a method for driving the same.
Organic EL (electroluminescent) display devices have been drawing attention as display devices characterized by, for example, being thin and achieving high image quality and low power consumption, and such organic EL display devices are now actively being developed. One known method for driving such an organic EL display device is a method called SSD (source shared driving; hereinafter, an “SSD method”). Accordingly, an organic EL display device employing an SSD method will be described below.
A data line driver 30 generates R, G, and B data signals in accordance with data and a control signal SC1 provided by a display control circuit 20, and, for each horizontal period, supplies the data signals for one horizontal line respectively to the data lines Dr1 to Drm, Dg1 to Dgm, and Db1 to Dbm. A scanning line driver 50 generates scanning signals in accordance with a control signal SC2 provided by the display control circuit 20, and supplies the generated signals sequentially to the scanning lines S1 to Sn. As a result, pixels connected to the scanning lines provided with the scanning signals are sequentially selected.
Similarly, during a second-row scanning period, the data lines Dr1 and Dg1 are respectively supplied with data signals R2 and G2. Moreover, simultaneously with the data line Db1 being supplied with a data signal B2, the scanning line S2 is provided with a low-level scanning signal Scan2. As a result, the data signals R2, G2, and B2 are simultaneously written to pixels r2, g2, and b2. Note that among the periods that represent the statuses of the scanning lines S1 to S5 in
Similarly, during the second-row scanning period, the selection transistor Mb is rendered in ON state, and simultaneously with the data signal B2 being supplied to the data line Db2, the scanning signal Scan2 being provided to the scanning line S2 is set to low level. As a result, the data signals R2, G2, and B2 being respectively held in the data capacitors Cdr1, Cdg1, and Cdb1 are simultaneously written to the pixels r2, g2, and b2 in the second row. Thereafter, the writing of data signals will be similarly repeated until data signals Rn, Gn, and Bn are respectively written to pixels rn, gn, and bn in the n'th row.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-79580
In the drive method shown in
Accordingly, the higher the definition of the image that is to be displayed becomes, the more difficult it becomes to ensure sufficient writing time. If sufficient writing time cannot be ensured, there arise such problems as a decrease in display image resolution and noticeably uneven luminance due to threshold voltage variations among drive transistors included in pixel circuits which serve as pixels.
Furthermore, in the drive method shown in
Therefore, it is desired to provide a display device employing an SSD method and capable of suppressing the occurrence of uneven luminance and providing high image quality display, and also desired to provide a method for driving the same.
A first aspect of the present invention is directed to a method for driving an active-matrix display device for displaying a color image based on a plurality of colors by supplying pixel circuits with a plurality of data signals in a time division manner, the data signals respectively corresponding to the colors, the display device including:
a plurality of data lines to be supplied with data signals;
a plurality of scanning lines to be sequentially supplied with scanning signals for selecting the pixel circuits;
a plurality of pixel circuits provided corresponding to the data lines and the scanning lines, each pixel circuit corresponding to any one of the colors;
a scanning line driver circuit configured to sequentially select the scanning lines;
a plurality of select/output circuits configured to sequentially supply the data signals to the data lines, each data signal corresponding to any one of the colors; and
a data line driver circuit configured to supply the data signals respectively to the select/output circuits, wherein,
each of the pixel circuits corresponding to the colors includes:
an electro-optical element;
a drive transistor configured to control a current flowing through the electro-optical element and having a control terminal and a first conductive terminal electrically connected to each other when the scanning line is being selected; and
a capacitive storage element configured to hold a potential applied at a node connecting the control terminal and the first conductive terminal of the drive transistor,
the select/output circuit supplies the data lines with respectively corresponding data signals representing at least one of the colors, and
the scanning line driver circuit sequentially drives the scanning lines and thereby supplies data signals to the nodes provided in the pixel circuits corresponding to the colors represented by the data signals, with the result that potentials applied at the nodes are held in the capacitive storage elements, the data signals including the data signals representing the at least one of the colors and data signals previously supplied to the data lines and representing a color not represented by the data signals representing the at least one of the colors.
An eleventh aspect of the present invention is directed to a method for driving a display device providing color display based on a plurality of colors by supplying data signals to pixel circuits in a time division manner, each data signal corresponding to any one of the colors,
the display device includes a plurality of data lines to be supplied with data signals, a plurality of scanning lines, a plurality of pixel circuits provided corresponding to the data lines and the scanning lines, each pixel circuit corresponding to any one of the colors, and a plurality of select/output circuits configured to sequentially supply the data signals to the data lines, each data signal corresponding to any one of the colors,
each of the pixel circuits corresponding to the colors includes an electro-optical element, a drive transistor configured to control a current flowing through the electro-optical element and having a control terminal and a first conductive terminal electrically connected to each other when a corresponding scanning line is being selected, and a capacitive storage element configured to hold a potential applied at a node connecting the control terminal and the first conductive terminal of the drive transistor, and
the method including the steps of:
In the first aspect, in the display device employing an SSD method, data signals representing at least one of the colors and data signals previously supplied to the data lines and representing a color not represented by the data signals representing the at least one of the colors are outputted by the select/output circuit and supplied to nodes provided in pixel circuits corresponding to the respective colors. Accordingly, it is possible to ensure sufficient writing time for writing both the data signals that correspond to the at least one of the colors and the data signals that correspond to the other color(s) to respectively corresponding pixel circuits during the same scanning period, thereby eliminating the risk of the data signals not being written correctly due to the shortage of writing time. Thus, it is possible to suppress the occurrence of uneven luminance due to threshold voltage variations and write data signals correctly to all pixels, whereby the display device can display a high-definition image.
The eleventh aspect renders it possible to achieve effects similar to those achieved by the first aspect.
Hereinafter, first through fourth embodiments will be described with reference to the accompanying drawings. Note that all transistors in each embodiment will be described as being of P-channel type, but the present invention is not limited to this, and the transistors may be of N-channel type. Moreover, the transistors in each embodiment are, for example, thin-film transistors, but the present invention is not limited to this.
<1.1 Configuration of the Organic EL Display Device>
The display portion 10 is provided with (m×2) data lines (where m is an integer of 2 or more). More specifically, there are disposed data lines Dr1 to Dr(2m/3), data lines Dg1 to Dg(2m/3), and data lines Db1 to Db(2m/3), and further, there are n scanning lines S1 to Sn, disposed perpendicular to these data lines. Moreover, the display portion 10 has pixel circuits provided at respective intersections of the data lines and the scanning lines. More specifically, there are provided (2/3×m×n) pixel circuits 11r, corresponding to the intersections of the m data lines Dr1 to Drm and the n scanning lines S1 to Sn, also provided (2/3×m×n) pixel circuits 11g corresponding to the intersections of the m data lines Dg1 to Dgm and the n scanning lines S1 to Sn, and further provided (2/3×m×n) pixel circuits 11b corresponding to the intersections of the m data lines Db1 to Dbm and the n scanning lines S1 to Sn. Accordingly, the display portion 10 is provided with a total of (2×m×n) pixel forming portions.
The display portion 10 has n emission lines E1 to En serving as control lines disposed parallel to the n scanning lines S1 to Sn. The data lines Dr1 to Dr(2m/3), Dg1 to Dg(2m/3), and Db1 to Db(2m/3) are connected to the demultiplexing portion 40. The n scanning lines S1 to Sn are connected to the scanning line driver 50. The n emission lines E1 to En are connected to the emission line driver 60.
Furthermore, the display portion 10 has power lines (not shown) disposed in common to the pixel circuits 11. More specifically, disposed is the power line that supplies a high-level potential ELVDD for driving organic EL elements (also referred to as “electro-optical elements”) to be described later (the power line will be referred to below as the “high-level power line” and denoted by the same symbol ELVDD as the high-level power source potential), and also disposed is the power line that supplies a low-level potential ELVSS for driving the organic EL elements (the power line will be referred to below as the “low-level power line” and denoted by the same symbol ELVSS as the low-level power source potential). Moreover, there is disposed an initialization line for supplying an initialization potential Vini for an initialization operation to be described later (the initialization line will be denoted by the same symbol Vvini as the initialization potential). These potentials are supplied by a power circuit (not shown). In the present embodiment, the high-level power line ELVDD realizes a first power line, and the low-level power line ELVSS realizes a second power line.
The (2m/3) data lines Dr1 to Dr(2m/3) are respectively connected to (2m/3) data capacitors Cdr1 to Cdr(2m/3). The (2m/3) data lines Dg1 to Dg(2m/3) are respectively connected to (2m/3) data capacitors Cdg1 to Cdg(2m/3). The (2m/3) data lines Db1 to Db(2m/3) are respectively connected to (2m/3) data capacitors Cdb1 to Cdb(2m/3). Note that each data capacitor is, for example, grounded at one terminal (the terminal that is not connected to the data line), but the present invention is not limited to this. Moreover, the data capacitors Cdgi to Cdg1 may include capacitors and parasitic capacitance created by data lines and pixels, or may simply be parasitic capacitance created by data lines and pixels. Note that R, G, and B data capacitors will also be collectively referred to as capacitive storage elements, which include parasitic capacitance.
The display control circuit 20 outputs various control signals to the data line driver 30, the demultiplexing portion 40, the scanning line driver 50, and the emission line driver 60. More specifically, the display control circuit 20 outputs a data start pulse DSP, a data clock DCK, display data DA, and a latch pulse LP to the data line driver 30. The display data DA includes R, G, and B data. The display control circuit 20 also outputs data control signals SSDr, SSDg, and SSDb to the demultiplexing portion 40. The display control circuit 20 also outputs a scanning start pulse SSP and a scanning clock SCK to the scanning line driver 50. The display control circuit 20 further outputs an emission start pulse ESP and an emission clock ECK to the emission line driver 60.
The data line driver 30 includes unillustrated elements, such as an m-bit shift register, a sampling circuit, a latch circuit, and m D/A converters. The shift register has m bistable circuits cascaded together, and transfers the data start pulse DSP supplied to the first stage, in synchronization with the data clock DCK, with the result that a sampling pulse is outputted from each stage. Concurrently with the outputting of the sampling pulse, the sampling circuit is supplied with the display data DA. The sampling circuit memorizes the display data DA in accordance with the sampling pulse. Once the sampling circuit memorizes the display data DA for one row, the display control circuit 20 outputs the latch pulse LP to the latch circuit. Upon reception of the latch pulse LP, the latch circuit holds the display data DA being memorized in the sampling circuit.
The D/A converters are provided corresponding to m data output lines di to dm respectively connected to m output terminals (not shown) of the data driver 30, in order to supply the data output lines d1 to dm with data signals, which are analog signal voltages converted by the D/A converters from the display data DA being held in the latch circuit. Since the display device according to the present embodiment performs color display in the three primary colors, R, G, and B, and employs an SSD method, the R, G, and B data signals are outputted to the data output lines in a time division manner.
The demultiplexing portion 40 includes demultiplexers 411 to 41m. For example, the demultiplexer 411 has input terminals, each being connected to one data output line d1. The demultiplexer 411 has two output terminals respectively connected to the data lines Dr1 and Dg1. The demultiplexer 411 supplies sequentially provided R and G data signals respectively to the data lines Dr1 and Dg1 from the two output terminals. Similarly, the demultiplexer 412 supplies sequentially provided B and R data signals respectively to the data lines Db1 and Dr2 from two output terminals. Note that the operation of the demultiplexers 411 and 412 will be described in detail later.
The scanning line driver 50 drives the n scanning lines S1 to Sm. More specifically, the scanning line driver 50 includes unillustrated elements, such as a shift register and a buffer. The shift register sequentially transfers the scanning start pulse SSP in synchronization with the scanning clock SCK. Scanning signals, which are outputs from stages in the shift register, are supplied to corresponding scanning lines Sj (where j=an integer from 1 to n) via the buffer. By an active scanning signal (in the present embodiment, a low-level signal), (2m/3) pixel circuits 11 connected to the scanning line Sj are collectively selected.
The emission line driver 60 drives the n emission lines E1 to En. More specifically, the emission line driver 60 includes unillustrated elements, such as a shift register and a buffer. The shift register sequentially transfers the emission start pulse ESP in synchronization with the emission clock ECK. Emission signals, which are outputs from the stages in the shift register, are supplied to corresponding emission lines Ej (where j=an integer from 1 to n) via the buffer.
As shown in
<1.2 Connection Relationship Between the Pixel Circuit and the Data Signal Lines>
As shown in
Accordingly, when the data control line ASW1 is provided with a low-level data control signal SSD1, the selection transistors Mr1, Mb1, and Mg2 are rendered in ON state, with the result that the data output line d1 and the data line Dr1 are connected via the selection transistor Mr1, the data output line d2 and the data line Db1 are connected via the selection transistor Mb1, and the data output line d3 and the data line Dg2 are connected via the selection transistor Mg2. Similarly, when the data control line ASW2 is provided with a low-level data control signal SSD2, the data output line d1 and the data line Dg1 are connected via the selection transistor Mg1, the data output line d2 and the data line Dr2 are connected via the selection transistor Mr2, and the data output line d3 and the data line Db2 are connected via the selection transistor Mb2.
For convenience of description, the number of pixel circuits 11r, 11g, or 11b in each set connected to the R, G, and B data lines has been described as five. However, in actuality, the number of pixel circuits 11r, 11g, or 11b in each set connected to the data lines is n, as shown in
<1.3 Configuration of the Pixel Circuit>
Next, the configuration of the pixel circuit 11 will be described.
The pixel circuit 11r includes one organic EL element OLED, six transistors M1 to M6, and one storage capacitor Cst (also called as a “capacitive storage element”). More specifically, the pixel circuit 11r includes an organic EL element OLED, a drive transistor M1, a writing transistor M2, a compensation transistor M3, an initialization transistor M4, a power supply transistor M5, an emission control transistor M6, and a storage capacitor Cst serving as a capacitive element. The drive transistor M1 has a gate terminal, a first conductive terminal, and a second conductive terminal. As for the drive transistor M1, the first and second conductive terminals respectively serve as source and drain terminals, or vice versa, depending on carrier flow. The pixel circuit 11g includes the same elements as those of the pixel circuit 11r. Note that the first conductive terminal of the drive transistor M1 is a conductive terminal connected to the high-level power line ELVDD via the power supply transistor M5, and the second conductive terminal is a conductive terminal connected to the organic EL element OLED via the emission control transistor M6.
The pixel circuit 11r is connected to a scanning line Sj (also referred to as a “current scanning line”), a scanning line Sj-1 immediately preceding the current scanning line Sj (also referred to as a “previous scanning line”), an emission line Ej, the data line Dr1, the high-level power line ELVDD, the low-level power line ELVSS, and the initialization line Vini. Note that, as described above, the data line Dr1 is connected to the data capacitor Cdr1, and the data line Dg1 is connected to the data capacitor Cdg1.
In the pixel circuit 11r, the writing transistor M2 has a gate terminal connected to the current scanning line Sj, and a source terminal connected to the data line Dr1. In the pixel circuit 11r, when the current scanning line Sj is selected, the writing transistor M2 supplies the first conductive terminal of the drive transistor M1 with an R data signal being held in the data capacitor Cdr1, and in the pixel circuit 11g, when the current scanning line Sj is selected, the writing transistor M2 supplies the first conductive terminal of the drive transistor M1 with a G data signal being held in the data capacitor Cdg1.
The drive transistor M1 is connected at the first conductive terminal to the drain terminal of the writing transistor M2 and at the gate terminal to a node N. The node N is a node to which a drain terminal of the compensation transistor M3 and a first terminal of the storage capacitor Cst are connected; a potential at the node N is provided to the gate terminal of the drive transistor M1 as a gate voltage. The drive transistor M1 supplies the organic EL element OLED with a drive current in accordance with the gate voltage.
The compensation transistor M3 is provided between the gate terminal and the second conductive terminal of the drive transistor Ml. The compensation transistor M3 has a gate terminal connected to the current scanning line Sj. When the current scanning line Sj is selected, the compensation transistor M3 connects (or diode-connects) the gate terminal and the second conductive terminal of the drive transistor M1. When the drive transistor M1 is diode-connected, the potential at the node N is set to a gate-to-source voltage Vgs lower than the voltage of the data signal by a threshold voltage, and the voltage Vgs is applied to the gate terminal of the drive transistor M1.
The initialization transistor M4 is connected between the gate terminal of the drive transistor M1 and the initialization line Vini, and has a gate terminal connected to the previous scanning line Sj-1. The initialization transistor M4 initializes a gate voltage Vg being provided to the gate terminal of the drive transistor M1, upon selection of the previous scanning line Sj-1.
The power supply transistor M5 is provided between the high-level power line ELVDD and the first conductive terminal of the drive transistor, and has a gate terminal connected to the emission line Ej. The power supply transistor M5 supplies a high-level potential ELVDD to the drain terminal of the drive transistor M1 upon selection of the emission line Ej.
The emission control transistor M6 is provided between the second conductive terminal of the drive transistor M1 and the organic EL element OLED, and has a gate terminal connected to the emission line Ej. The emission control transistor M6 transmits a drive current to the organic EL element OLED upon selection of the emission line Ej.
The storage capacitor Cst has the first terminal connected to the gate terminal of the drive transistor M1, and a second terminal connected to the high-level power line ELVDD. The storage capacitor Cst holds the gate voltage Vg being applied to the gate terminal of the drive transistor M1 when the compensation transistor M3 and the initialization transistor M4 of the pixel circuit 11r are in OFF state.
The organic EL element OLED has an anode (a terminal of the organic EL element OLED) connected to the second conductive terminal of the drive transistor M1 via the emission control transistor M6 and a cathode (the other terminal of the organic EL element OLED) connected to the low-level power line ELVSS. The organic EL element OLED emits light with a luminance in accordance with a drive current. Although not shown in any figures, the configuration of the pixel circuit 11b included in the present embodiment is basically the same as the configuration of the pixel circuits 11r and 11g, and therefore, any description thereof will be omitted. Note that the configuration of the pixel circuits 11b included in the other demultiplexers 412 to 41m is the same as that of the pixel circuits 11r and 11g, and the configuration of the demultiplexers 412 to 41m is the same as that of the demultiplexer 411. Accordingly, any descriptions thereof will be omitted.
<1.4 Drive Method>
A drive method in which data signals are written to the pixel circuits 11r, 11g, and 11b of the display device will be described with respect to the case where, of the three demultiplexers 411 to 413 shown in
Initially, the data output line d1 is provided with a data signal G11 in the data signal D1 during a blanking period which starts after data signals are written to the pixels in the n′th row for the previous frame and ends before data signals are written to the pixels in the first row for the current frame. Moreover, the data control line ASW2 is provided with a low-level data control signal SSD2. Accordingly, the selection transistor Mg1 of the demultiplexer 411 is rendered in ON state, with the result that the data signal G11 is supplied from the data output line d1 to the data line Dg1 and held in the data capacitor Cdg1. Similarly, the selection transistor Mr2 of the demultiplexer 412 is rendered in ON state, with the result that a data signal R21 is supplied from the data output line d2 to the data line Dr2 and held in the data capacitor Cdr1.
Next, during a first-row scanning period, the data output line d1 is provided with a data signal R11 in the data signal D1, and the data output line d2 is provided with a data signal B11 in the data signal D2. Moreover, the data control line ASW1 is provided with a low-level data control signal SSD1. Accordingly, the selection transistor Mr1 of the demultiplexer 411 is rendered in ON state, with the result that the data signal R11 is supplied from the data output line d1 to the data line Dr1 and held in the data capacitor Cdr1. Similarly, the selection transistor Mb1 of the demultiplexer 412 is rendered in ON state, with the result that the data signal B11 is supplied from the data output line d2 to the data line Db1 and held in the data capacitor Cdb1.
Simultaneously, the scanning line S1 is selected, upon which the data signal R11 supplied to the data line Dr1 is provided from the data line Dr1 to the pixel r11, with the result that the node N is provided with a gate-to-source voltage, which is lower than the voltage of the data signal
R11 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel r11, and the gate-to-source voltage is held in the storage capacitor Cst. The data signal B11 supplied to the data line Db1 is provided from the data line Db1 to the pixel b11, with the result that the node N is provided with a gate-to-source voltage, which is lower than the voltage of the data signal B11 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel b11, and the gate-to-source voltage is held in the storage capacitor Cst. The data signal G11 supplied to the data line Dg1 during the blanking period and being held in the data capacitor Cdg1is provided from the data line Dg1 to the pixel g11, with the result that the node N is provided with a gate-to-source voltage, which is lower than the voltage of the data signal G11 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel gui, and the gate-to-source voltage is held in the storage capacitor Cst. In this manner, the data signals R11 and B11 to be respectively written to the pixels ru and b11 are the signals supplied to the data lines Dr1 and Db1 during the first-row scanning period. However, the signal that is used as the data signal G11 to be written to the pixel g11 is the signal supplied to the data line Dg1 during the immediately preceding blanking period and being held in the data capacitor Cdg1.
Next, during a second-row scanning period, the data output line d1 is provided with a data signal G12 in the data signal D1, and the data output line d2 is provided with a data signal R22 in the data signal D2. Moreover, the data control line ASW2 is provided with a low-level data control signal SSD2. Accordingly, the selection transistor Mg1 of the demultiplexer 411 is rendered in ON state, with the result that the data signal G12 is supplied from the data output line d1 to the data line Dg1 and held in the data capacitor Cdg1. Similarly, the selection transistor Mr2 of the demultiplexer 412 is rendered in ON state, with the result that the data signal R22 is supplied from the data output line d2 to the data line Dr2 and held in the data capacitor Cdr2.
Simultaneously, the scanning line S2 is selected, upon which the data signal G12 supplied to the data line Dg1 is provided from the data line Dg1 to the pixel g12, with the result that the node N is provided with a gate-to-source voltage, which is lower than the voltage of the data signal G12 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel g12, and the gate-to-source voltage is held in the storage capacitor Cst. The data signal R11 supplied to the data line Dr1 during the first-row scanning period and being held in the data capacitor Cdr1 is provided from the data line Dr1 to the pixel r12, with the result that the node N is provided with a gate-to-source voltage, which is lower than the voltage of the data signal R11 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel r12, and the gate-to-source voltage is held in the storage capacitor Cst. The data signal B11 supplied to the data line Db1 during the first-row scanning period and being held in the data capacitor Cdb1 is provided from the data line Db1 to the pixel b12, with the result that the node N is provided with a gate-to-source voltage, which is lower than the voltage of the data signal B11 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel b12, and the gate-to-source voltage is held in the storage capacitor Cst. In this manner, the data signal G12 to be written to the pixel g12 is the signal supplied to the data line Dg1 during the second-row scanning period. However, the signals that are used as the data signals R11 and B11 to be respectively written to the pixels r12 and b12 are the signals supplied to the data line Dr1 during the first-row scanning period.
Next, during a third-row scanning period, the data output line d1 is provided with a data signal R12 in the data signal D1, and the data output line d2 is provided with a data signal B12 in the data signal D2. Moreover, the data control line ASW1 is provided with a low-level data control signal SSD1. Accordingly, the selection transistor Mr1 of the demultiplexer 411 is rendered in ON state, with the result that the data signal R12 is supplied from the data output line d1 to the data line Dr1 and held in the data capacitor Cdr1. Similarly, the selection transistor Mb1 of the demultiplexer 412 is rendered in ON state, with the result that the data signal B12 is supplied from the data output line d2 to the data line Db1 and held in the data capacitor Cdb1. The data signal G12 supplied to the data line Dg1 and being held in the data capacitor Cdg1 is provided from the data line Dg1 to the node N via the drive transistor M1 in the pixel g13 and held in the storage capacitor Cst.
Simultaneously, the scanning line S3 is selected, upon which the data signal R12 supplied to the data line Dr1 is provided from the data line Dr1 to the pixel r13, with the result that the node N is provided with a gate-to-source voltage, which is lower than the voltage of the data signal R12 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel r12, and the gate-to-source voltage is held in the storage capacitor Cst. The data signal B12 supplied to the data line Db1 is provided from the data line Db1 to the pixel b13, with the result that the node N is provided with a gate-to-source voltage, which is lower than the voltage of the data signal B12 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel b13, and the gate-to-source voltage is held in the storage capacitor Cst. The data signal G12 supplied to the data line Dg1 during the second-row scanning period and being held in the data capacitor Cdg1 is provided from the data line Dg1 to the pixel g13, with the result that the node N is provided with a gate-to-source voltage lower than the voltage of the data signal G12 by a threshold voltage, via the diode connection of the drive transistor M1 and the compensation transistor M3 in the pixel g13, and the gate-to-source voltage is held in the storage capacitor Cst. In this case, the data signals R12 and B12 to be supplied are the signals respectively supplied to the data lines Dr1 and Db1 during the third-row scanning period. However, the signal that is used as the data signal G12 is the signal supplied to the data line Dg1 during the second-row scanning period. Note that the operations of writing the data signals to the pixels that have been described in detail above will be collectively referred to below by the phrase such as “writing data signals to pixels”.
Thereafter, similarly, during a fourth-row scanning period, the data signal R12 supplied to the data line Dr1 is written to the pixel r14, a data signal G13 supplied to the data line Dg1 is written to the pixel g14, and the data signal B12 supplied to the data line Db1 is written to the pixel b14. During a fifth-row scanning period, a data signal R13 supplied to the data line Dr1 is written to the pixel r15, the data signal G13 supplied to the data line Dg1 is written to the pixel g15, and a data signal B13 supplied to the data line Db1 is written to the pixel b15.
<1.5 Effects>
In the present embodiment, one or two of the data signals to be written to the R, G, and B pixels during one scanning period are a data signal or data signals that has or have been written to the data line(s) during the previous scanning period and held in the data capacitor(s), and such data signals are utilized and written simultaneously to corresponding pixels. Accordingly, it is possible to ensure sufficient writing time for writing R, G, and B data signals respectively to the R, G, and B pixels during the scanning period, thereby eliminating the risk of the data signals not being written correctly due to the shortage of writing time. Thus, even for a display device with a number of pixels, data signals can be written correctly to all pixels, whereby the display device can display a high-definition image.
The display portion 10 is provided with (3×m) data lines (where m is an integer of 2 or more).
Specifically, there are disposed m data lines Dr1, to Drm, m data lines Dg1 to Dgm, and m data lines Db1 to Dbm. Further, there are n scanning lines S1 to Sn disposed perpendicularly to these data lines. Moreover, there are pixel circuits disposed at respective intersections of the data lines and the scanning lines. More specifically, there are provided (m×n) pixel circuits 11r corresponding to the intersections of the m data lines Dr1 to Drm and the n scanning lines S1 to Sn, (m×n) pixel circuits 11g corresponding to the intersections of the m data lines Dg1 to Dgm and the n scanning lines S1 to Sn, and (m×n) pixel circuits 11b corresponding to the intersections of the m data lines Db1 to Dbm and the n scanning lines S1 to Sn.
Furthermore, the display portion 10 has n emission lines E1 to En serving as control lines disposed parallel to the n scanning lines S1 to Sn. The data lines are connected to the demultiplexers such that each demultiplexer is connected to a total of three data lines, i.e., one from each of the groups Dr1 to Drm, Dg1 to Dgm, and Db1 to Dbm. The n scanning lines S1 to Sn are connected to the scanning line driver 50. The n emission lines E1 to En are connected to the emission line driver 60.
The display device according to the present embodiment performs color display in the three primary colors, R, G, and B, and employs an SSD method, and therefore, the data line driver 30 supplies R, G, and B data signals to data output lines d1 to dm in a time division manner, as in the display device shown in
The demultiplexing portion 40 includes m demultiplexers 421 to 42m. The demultiplexers have input terminals, each being connected to any one of the m data output lines d1 to dm. Each demultiplexer has three output terminals, each being connected to three data lines. For example, the three output terminals of the demultiplexer 421 are respectively connected to the data lines Dr1, Dg1, and Db1. The operation of the demultiplexer 421 is controlled by data control signals SSDr, SSDg, and SSDb. The demultiplexer 421 is sequentially supplied with R, G, and B data signals, and supplies the R, G, and B data signals respectively to the data lines Dr1, Dg1, and Db1 from the three output terminals. Similarly, the demultiplexers 422 to 42m are controlled by data control signals SSDr, SSDg, and SSDb, sequentially supplied with R, G, and B data signals, and supply the R, G, and B data signals respectively to the data lines Dr2 to Drm, the data lines Dg2 to Dgm, and the data lines Db2 to Dbm from three respective output terminals.
It should be noted that the scanning line driver 50 and the emission line driver 60 are the same as those described in the first embodiment, and therefore, any descriptions thereof will be omitted.
As shown in
It should be noted that for the sake of convenience, the number of each of the R, G, and B pixels respectively connected to the R, G, and B data lines has been described as five. However, in actuality, n R pixels, n G pixels, and n B pixels are connected to the respective lines, as shown in
Next, the configuration of the pixel circuit 11 will be described.
<2.1 Drive Method>
A drive method in which data signals are written to the pixel circuits 11 of the display device will be described with respect to the case where R, G, and B data signals are respectively written to the pixels r1 to r5, g1 to g5, and b1 to b5 respectively connected to the data lines Dr1, Dg1, and Db1 extending from the demultiplexer 421 shown in
The data output line d1 connected to the demultiplexer 421 is provided with a data signal D1 consisting of R, G, and B data signals. Initially, during a first half of a blanking period, the data control line ASWg is provided with a low-level data control signal SSDg. As a result, the selection transistor Mg of the demultiplexer 421 is rendered in ON state, with the result that the data line Dg1 is supplied with a data signal G1 from the data output line d1. Next, during a second half of the blanking period, the data control line ASWb is provided with a low-level data control signal SSDb. As a result, the selection transistor Mb is rendered in ON state, with the result that the data line Db1 is supplied with a data signal B1 from the data output line d1.
Next, during a first-row scanning period, a data control signal SSDr is set to low level, with the result that the data line Dr1 is supplied with a data signal R1 from the data output line d1. Moreover, at the start of the first-row scanning period, the scanning line S1 is selected. Accordingly, the data signal R1 supplied to the data line Dr1 is written to the pixel r1, the data signal G1 supplied to the data line Dg1 is written to the pixel g1, and the data signal B1 supplied to the data line Db1 is written to the pixel b1. In this case, the data signal R1 is the signal supplied to the data line Dr1 during the first-row scanning period. However, the signals that are used as the data signals G1 and B1 are the signals respectively supplied to the data lines Dg1 and Db1 during the immediately preceding blanking period.
Next, during a second-row scanning period, the data control signal SSDg is set to low level, with the result that the data line Dg1 is supplied with a data signal G2 from the data output line d1. Moreover, at the start of the second-row scanning period, the scanning line S2 is selected. Accordingly, the data signal R1 supplied to the data line Dr1 is written to the pixel r2, the data signal G2 supplied to the data line Dg1 is written to the pixel g2, and the data signal B1 supplied to the data line Db1 is written to the pixel b2. In this case, the data signal G2 is the signal supplied to the data line Dg1 during the second-row scanning period. However, the signal that is used as the data signal R1 is the signal supplied to the data line Dr1 during the first-row scanning period, and the signal that is used as the data signal B1 is the signal supplied to the data line Db1 during the blanking period.
Next, during a third-row scanning period, the data control signal SSDb is set to low level, with the result that the data line Db1 is supplied with a data signal B2 from the data output line d1. Moreover, at the start of the third-row scanning period, the scanning line S3 is selected. Accordingly, the data signal B2 supplied to the data line Db1 is written to the pixel b3, the data signal G2 supplied to the data line Dg1 is written to the pixel g3, and the data signal B2 supplied to the data line Db1 is written to the pixel b3. In this case, the data signal B2 is the signal supplied to the data line Db1 during the third-row scanning period. However, the signal that is used as the data signal R1 is the signal supplied to the data line Dr1 during the first-row scanning period, and the signal that is used as the data signal B2 is the signal supplied to the data line Db1 during the second-row scanning period.
Thereafter, similarly, during a fourth-row scanning period, the data signal R2 supplied to the data line Dr1 is written to the pixel r4, the data signal G2 supplied to the data line Dg1 is written to the pixel g4, and the data signal B2 supplied to the data line Db1 is written to the pixel b4. During a fifth-row scanning period, the data signal R2 supplied to the data line Dr1 is written to the pixel r5, a data signal G3 supplied to the data line Dg1 is written to the pixel gg, and the data signal B2 supplied to the data line Db1 is written to the pixel b5. During a sixth-row scanning period, the data signal R2 supplied to the data line Dr1 is written to the pixel r6, the data signal G3 supplied to the data line Dg1 is written to the pixel b6, and a data signal B3 supplied to the data line Db1 is written to the pixel b6.
Thereafter, similarly, for each of the R, G, and B pixels, the same data signal is written to three consecutive pixels. Note that in
<2.3 Effects>
In the present embodiment, the data signal that is supplied from the data output line d1 during one scanning period is any one of the R, G, and B data signals, and the remaining two data signals are not supplied. Accordingly, the data signals that are not supplied during that one scanning period are supplied during a preceding scanning period and held in data capacitors, and the data signals that are being held are utilized and simultaneously written to respectively corresponding pixels. In this case, using the two data signals supplied during the preceding scanning period eliminates the need for time to supply the two data signals during the one scanning period and therefore saves time correspondingly. Accordingly, it is possible to ensure sufficient time for writing the R, G, and B data signals respectively to the R, G, and B pixels during the one scanning period, thereby eliminating the risk of the data signals not being written correctly due to the shortage of writing time. Thus, even in the case of a display device with a number of pixels, data signals can be written correctly to all pixels, and therefore, the display device can display a high-definition image.
A display device according to a third embodiment will be described. The configuration of the display device according to the present embodiment, the connection relationship between the demultiplexer 421 and the pixels r1 to r5, g1 to g5, and b1 to b5, and the configuration of the pixel circuits 11r to 11b are the same as in the second embodiment, and therefore, any figures and descriptions thereof will be omitted.
In the method in the second embodiment, each demultiplexer selects one of the three selection transistors for each scanning period and writes a data signal supplied to the data output line d1 to a data line via the selected selection transistor, and signals supplied during a preceding scanning period and being held in data capacitors are utilized as two other data signals. However, in a drive method in the present embodiment, two of the three selection transistors are sequentially rendered in ON state for each scanning period, two data signals supplied via the two selection transistors in ON state are written to two respectively corresponding data lines, and a data signal supplied during a preceding scanning period and being held in a data capacitor is utilized as the remaining one data signal. Accordingly, the drive method in the present embodiment will be described in detail below.
<3.1 Drive Method>
As shown in
During a first half of a first-row scanning period, the data output line d1 is provided with a data signal R1. Moreover, the data control line ASWr is provided with a low-level data control signal SSDr. As a result, the selection transistor Mr is rendered in ON state, with the result that the data signal R1 is supplied from the data output line d1 to the data line Dr1. During a second half, the data output line d1 is provided with a data signal G1. Moreover, the data control line ASWg is provided with a low-level data control signal SSDg. Accordingly, the selection transistor Mg is rendered in ON state, with the result that the data signal G1 is supplied from the data output line d1 to the data line Dg1.
When the scanning line S1 is selected at the start of the second half, the data signal R1 supplied to the data line Dr1 is written to the pixel r1, the data signal B1 supplied to the data line Db1 is written to the pixel g1, and the data signal B1 supplied to the data line Db1 is written to the pixel b1. In this case, the data signals R1 and G1 to be respectively written to the pixels r1 and b1 are the signals respectively supplied to the data lines Dr1 and Dg1 during the first-row scanning period. However, the signal that is used as the data signal B1 to be written to the pixel b1 is the signal supplied to the data line Db1 during the immediately preceding blanking period.
During a first half of a second-row scanning period, the data output line d1 is provided with a data signal B2. Moreover, the data control line ASWb is provided with a low-level data control signal SSDb. Accordingly, the selection transistor Mb is rendered in ON state, with the result that the data signal B2 is supplied from the data output line d1 to the data line Db1. During a second half, the data output line d1 is provided with a data signal R2. Moreover, the data control line ASWr is provided with a low-level data control signal SSDr. Accordingly, the selection transistor Mr is rendered in ON state, with the result that the data signal R2 is supplied from the data output line d1 to the data line Dr1.
When the scanning line S2 is selected at the start of the second half, the data signal R2 supplied to the data line Dr1 is written to the pixel r2, the data signal B2 supplied to the data line Db1 is written to the pixel b2, and the data signal G1 supplied to the data line Dg1 is written to the pixel g2. In this case, the data signals R2 and B2 to be respectively written to the pixels r2 and b2 are the signals respectively supplied to the data lines Dr1 and Dg1 during the second-row scanning period. However, the signal that is used as the data signal G1 to be written to the pixel g2 is the signal supplied to the data line Dg1 during the first-row scanning period.
During a first half of a third-row scanning period, the data output line d1 is provided with a data signal G2. Moreover, the data control line ASWg is provided with a low-level data control signal SSDg. Accordingly, the selection transistor Mg is rendered in ON state, with the result that the data signal G2 is supplied from the data output line d1 to the data line Dg1. During a second half, the data output line d1 is provided with a data signal B3. Moreover, the data control line ASWb is provided with a low-level data control signal SSDb. Accordingly, the selection transistor Mb is rendered in ON state, with the result that the data signal B2 is supplied from the data output line d1 to the data line Db1.
When the scanning line S3 is selected at the start of the second half, the data signal G2 supplied to the data line Dg1 is written to the pixel g3, the data signal B3 supplied to the data line Db1 is written to the pixel b3, and the data signal R2 supplied to the data line Dr1 is written to the pixel r3. In this case, the data signals G2 and B3 to be respectively written to the pixels g3 and b3 are the signals supplied to the data lines Dg1 and Db1 during the third-row scanning period. However, the signal that is used as the data signal R2 to be written to the pixel r3 is the signal supplied to the data line Dr1 during the second-row scanning period.
Thereafter, similarly, during a fourth-row scanning period, data signals R3, G3, and B3 are respectively written to the pixels r4, g4, and b4. During a fifth-row scanning period, a data signal R4 is written to the pixel r5, the data signal G3 is written to the pixel g5, and a data signal B4 is written to the pixel b5. During a sixth-row scanning period, the data signal R4 is written to the pixel r6, a data signal G4 is written to the pixel g6, and a data signal B5 is written to the pixel b6.
<3.2 Effects>
In the present embodiment, the data signals to be supplied from the data output line d1 during one scanning period are any two of the R, G, and B data signals, and the remaining one data signal is not supplied. Accordingly, the data signal that is not supplied during that one scanning period is supplied during a preceding scanning period and held in a data capacitor, and such data signals that are being held are utilized and simultaneously written to corresponding pixels. In this case, the need for time to supply the remaining one data signal during the one scanning period is eliminated, and therefore, time can be saved correspondingly. Accordingly, it is possible to ensure sufficient time for writing the R, G, and B data signals respectively to the R, G, and B pixels during the one scanning period, thereby eliminating the risk of the data signals not being written correctly due to the shortage of writing time. Thus, even in the case of a display device with a number of pixels, data signals can be written correctly to all pixels, and therefore, the display device can display a high-definition image.
A display device according to a fourth embodiment will be described. The configuration of the display device according to the present embodiment and the configuration of the pixel circuits 11r to 11b are the same as in the second and third embodiments, and therefore, any figures and descriptions thereof will be omitted. However, the configuration of the demultiplexer differs from those in the second and third embodiments. Therefore, the configuration of the demultiplexer will be described below along with a drive method.
However, since no selection transistor Mg is provided, the data line Dg1 is directly connected to a terminal of the data line driver 30 from which a data signal G1 is outputted. Accordingly, whenever the data output line d1 is provided with a G data signal, the G data signal is written to the data line Dg1, and moreover, it is preferred that the data signals G1 that are written to the pixels g1 to g5 connected to the scanning lines provided with low-level scanning signals vary every scanning period, but the same data signal G1 may be consecutively written to pixels whose scanning periods differ from each other.
<4.1 Drive Method>
A drive method in which data signals are written to the pixel circuits 11 of the display device will be described with respect to the case where R, G, and B data signals are respectively written to the pixels r1 to r5, g1 to g5, and b1 to b5 respectively connected to the data lines Dr1, Dg1, and Db1 extending from the demultiplexer 431 shown in
The data output line d1 connected to the demultiplexer 431 is provided with a data signal D1 consisting of R, G, and B data signals. Initially, during a blanking period, the data control line ASWb is provided with a low-level data control signal SSDb. Accordingly, the selection transistor Mb of the demultiplexer 431 is rendered in ON state, with the result that the data line Db1 is supplied with a data signal B1 from the data output line d1.
Next, during a first half of a first-row scanning period, a data control signal SSDr is set to low level, with the result that the data line Dr1 is supplied with a data signal R1 from the data output line d1. During a second half, the data line Dg1 is supplied with a data signal G1 from the data output line d1. Moreover, at the start of the second half, the scanning line S1 is selected. Accordingly, the data signal R1 supplied to the data line Dr1 is written to the pixel r1, the data signal G1 supplied to the data line Dg1 is written to the pixel g1, and the data signal B1 supplied to the data line Db1 is written to the pixel b1. In this case, the data signals R1 and G1 are the signals supplied to the data lines Dr1 and Dg1 during the first-row scanning period. However, the signal that is used as the data signal B1 is the signal supplied to the data line Db1 during the immediately preceding blanking period.
Next, during a first half of a second-row scanning period, the data control signal SSDb is set to low level, with the result that the data line Db1 is supplied with a data signal B2 from the data output line d1. During a second half, the data line Dg1 is supplied with a data signal G2 from the data output line d1. Moreover, at the start of the second half, the scanning line S2 is selected. Accordingly, the data signal B2 supplied to the data line Db1 is written to the pixel b2, the data signal G2 supplied to the data line Dg1 is written to the pixel g2, and the data signal R1 supplied to the data line Dr1 is written to the pixel r2. In this case, the data signals B2 and G2 are the signals respectively supplied to the data lines Db1 and Dg1 during the second-row scanning period. However, the signal that is used as the data signal R1 is the signal supplied to the data line Dr1 during the first-row scanning period.
Next, during a first half of a third-row scanning period, the data control signal SSDr is set to low level, with the result that the data line Dr1 is supplied with a data signal R2 from the data output line d1. During a second half, the data line Dg1 is supplied with a data signal G3 from the data output line d1. Moreover, at the start of the second half, the scanning line S3 is selected. Accordingly, the data signal R2 supplied to the data line Dr1 is written to the pixel r3, the data signal G3 supplied to the data line Dg1 is written to the pixel g3, and the data signal B2 supplied to the data line Db1 is written to the pixel b3. In this case, the data signals R2 and G3 are the signals respectively supplied to the data lines Db1 and Dg1 during the third-row scanning period. However, the signal that is used as the data signal B2 is the signal supplied to the data line Db1 during the second-row scanning period.
Thereafter, similarly, during a fourth-row scanning period, a data signal R2 supplied to the data line Dr1 is written to the pixel r4, a data signal G4 supplied to the data line Dg1 is written to the pixel g4, and the data signal B3supplied to the data line Db1 is written to the pixel b4. During a fifth-row scanning period, a data signal R3 supplied to the data line Dr1 is written to the pixel r5, a data signal G5 supplied to the data line Dg1 is written to the pixel g5, and the data signal B3 supplied to the data line Db1 is written to the pixel b5.
<4.2 Effects>
In the present embodiment, of the data signals that are supplied from the data output line d1 during each scanning period, the R and B data signals are alternatingly outputted to the respective data lines Dr1 and Db1 every scanning period, as in the other embodiments. On the other hand, the G data signal is outputted to the data line Dg1 during each scanning period. The G data signal is a signal which significantly affects image definition, and therefore, by the data line driver 30 outputting the G data signal during each scanning period, as in the embodiment, it is rendered possible to display a high-definition color image. Moreover, by changing the G data signal for each scanning period, a higher-definition color image can be displayed. Other effects are the same as those described in the other embodiments, and therefore, any descriptions thereof will be omitted.
<5. Other>
The display of the present embodiment is not limited to display panels with organic EL elements OLED, and any display panels with electro-optical elements may be employed so long as the luminance and/or the transmittance of the electro-optical elements are controlled by current. Examples of displays with such current-controlled electro-optical elements include EL displays, such as organic EL displays with organic light-emitting diodes (OLEDs) and inorganic EL displays with inorganic light-emitting diodes, and QLED displays with quantum-dot light-emitting diodes.
<6. Appendix>
Appendix 1 is directed to an active-matrix display device for displaying a color image based on a plurality of colors by supplying pixel circuits with a plurality of data signals in a time division manner, the data signals respectively corresponding to the colors, the display device including a plurality of data lines to be supplied with data signals, a plurality of scanning lines to be sequentially supplied with scanning signals for selecting the pixel circuits, a plurality of pixel circuits provided corresponding to the data lines and the scanning lines, each pixel circuit corresponding to any one of the colors, a scanning line driver circuit configured to sequentially select the scanning lines, a plurality of select/output circuits configured to sequentially supply the data signals to the data lines, each data signal corresponding to any one of the colors, and a data line driver circuit configured to supply the data signals respectively to the select/output circuits, each of the pixel circuits corresponding to the colors includes an electro-optical element, a drive transistor configured to control a current flowing through the electro-optical element and having a control terminal and a first conductive terminal electrically connected to each other when the scanning line is being selected, and a capacitive storage element configured to hold a potential applied at a node connecting the control terminal and the first conductive terminal of the drive transistor, wherein the select/output circuit supplies the data lines with respectively corresponding data signals representing at least one of the colors, and the scanning line driver circuit sequentially drives the scanning lines and thereby supplies data signals to the nodes provided in the pixel circuits corresponding to the colors represented by the data signals, with the result that potentials applied at the nodes are held in the capacitive storage elements, the data signals including the data signals representing the at least one of the colors and data signals previously supplied to the data lines and representing a color not represented by the data signals representing the at least one of the colors.
In Appendix 2 directed to a display device based on the display device of Appendix 1, a data signal that is used as a data signal to be provided to the pixel circuit, but not by the select/output circuit, during at least a first horizontal period within each frame period may be a data signal supplied to the data line by the select/output circuit and held in the capacitive element connected to the data line during a blanking period in a transition to the frame period from an immediately preceding frame period.
In the display device of Appendix 2, the data signal not provided by the select/output circuit during the horizontal period is supplied to the data line by the select/output circuit and held in the capacitive element connected to the data line during the blanking period in the transition to the frame period from the immediately preceding frame period. Accordingly, when data signals are written to pixel circuits, data signals held in capacitive elements during the blanking period can be used, and therefore, during the first horizontal period within each frame period, the time for supplying the data signals to the data lines can be reduced correspondingly. Thus, it is possible to ensure sufficient time for writing data signals to corresponding pixel circuits, thereby eliminating the risk of the data signals not being written correctly due to the shortage of writing time.
In Appendix 3 directed to a display device based on the display device of Appendix 1, the select/output circuit may include two selection transistors configured to sequentially select data signals corresponding to two colors and supply the data signals respectively to two corresponding data lines, and the two selection transistors may output data signals selected from the data signals corresponding to the two colors to the corresponding data lines, in accordance with data control signals respectively provided through two data control lines connected to control terminals of the selection transistors.
In the display device of Appendix 3, the select/output circuit includes the two selection transistors respectively connected to two data lines, and the two selection transistors output data signals selected from data signals corresponding to two colors to corresponding data lines, in accordance with data control signals respectively provided through two data control lines. Accordingly, it is possible to ensure sufficient writing time for writing a data signal that corresponds to a color to a pixel circuit corresponding to that color and also a data signal that corresponds to another color to a pixel circuit corresponding to that color, thereby eliminating the risk of the data signals not being written correctly due to the shortage of writing time.
In Appendix 4 directed to a display device based on the display device of Appendix 1, the select/output circuit may include three selection transistors configured to sequentially select data signals corresponding to three colors and supply the data signals respectively to three corresponding data lines, and the three selection transistors may select one or two data signals from the data signals corresponding to the three colors and output the one or two data signals to the corresponding data lines, in accordance with data control signals respectively provided through three data control lines connected to control terminals of the selection transistors.
In the display device of Appendix 4, the select/output circuit includes three selection transistors which are respectively connected to three data lines, and the three selection transistors output any one data signal for each horizontal period. Accordingly, it is possible to ensure sufficient writing time for writing a data signal that corresponds to a color to a pixel circuit corresponding to that color and also a data signal that corresponds to another color to a pixel circuit corresponding to that color, thereby eliminating the risk of the data signals not being written correctly due to the shortage of writing time.
In Appendix 5 directed to a display device based on the display device of Appendix 1, the data signals for the colors may include a green data signal, and the green data signal may be written for each horizontal period to the capacitive storage element of the pixel circuit to which the green data signal should be written.
In the display device of Appendix 5, since the G data signal is a signal which significantly affects image definition, by the data line driver 30 outputting the G data signal during each scanning period, it is rendered possible to display a high-definition color image.
In Appendix 6 directed to a display device based on the display device of Appendix 5, the green data signal may be a data signal for displaying a different image for each horizontal period.
In the display device of Appendix 6, the green data signal is a data signal for displaying a different image for each horizontal period, whereby it is rendered possible to display a higher-definition color image.
In Appendix 7 directed to a display device based on the display device of Appendix 1, which may further include first and second power lines for supplying a power source potential in common to the pixel circuits, the electro-optical element may be provided between the first and second power lines, the drive transistor may be provided in series to the electro-optical element between the first and second power lines, and each of the pixel circuits corresponding to the colors may further include a writing transistor provided between a second conductive terminal of the drive transistor and the data line and having a control terminal connected to the scanning line, and a compensation transistor provided between the control terminal and the first conductive terminal of the drive transistor and having a control terminal connected to the scanning line.
The display device of Appendix 7 achieves effects similar to those achieved by the display device of Appendix 1 where the writing transistor writes a data voltage to the pixel circuit, and the compensation transistor is used to compensate for changes of a threshold voltage of the drive transistor.
Appendix 8 is directed to a display device based on the display device of Appendix 7, which may further include a plurality of control lines provided along the scanning lines, and a control line driver circuit configured to cause the electro-optical element in the pixel circuit connected to the scanning line to emit light upon completion of a selection period during which the scanning line is being selected.
The display device of Appendix 8 renders it possible to control the duration of light emission by the electro-optical element.
In Appendix 9 directed to a display device based on the display device of Appendix 8, the pixel circuit may further include a power supply transistor provided between the first conductive terminal of the drive transistor and the first power line and having a control terminal connected to the control line, and an emission control transistor provided between the second conductive terminal of the drive transistor and a terminal of the electro-optical element and having a control terminal connected to the control line, and upon completion of the selection period for the scanning line, the control line driver circuit may supply the control line with a potential by which each of the power supply transistor and the emission control transistor of the pixel circuit is rendered conductive.
The display device of Appendix 9 achieves effects similar to those achieved by the display device of Appendix 8, by using the power supply transistor and the emission control transistor.
In Appendix 10 directed to a display device based on the display device of Appendix 7, each of a plurality of pixel circuits arranged in a direction in which the scanning line extends may further include an initialization transistor provided between an initialization line for supplying an initialization potential and the control terminal of the drive transistor or a terminal of the capacitive storage element, the initialization transistor having a control terminal connected to a scanning line immediately preceding the scanning line for the pixel circuits.
In the display device of Appendix 10, the initialization transistor initializes the potential at the control terminal of the drive transistor. Thus, it is possible to reliably write the data voltage to the pixel circuit in accordance with the data signal.
10 display portion
11 pixel circuit
20 display control circuit
30 data line driver (data line driver circuit)
40 demultiplexing portion
41
1 to 41m, 421 to 42m demultiplexer (select/output circuit)
50 scanning line driver (scanning line driver circuit)
60 emission line driver (control line driver circuit)
di (i is an integer from 1 to m) output line
Dri, Dgi, Dbi (i=an integer from 1 to m) data line
Sj (j =an integer from 1 to n) scanning line
Ej (j =an integer from 1 to n) emission line (control line)
M1 to M6, Mr, Mg, Mb transistor
Cst storage capacitor (capacitive storage element)
Cdri, Cdgi, Cdbi (i is an integer from 1 to m) data capacitor (capacitive element)
ELVDD high-level power line (first power line)
ELVSS low-level power line (second power line)
Vini initialization line
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2017/012560 | 3/28/2017 | WO | 00 |