WO2009142033A1 - 表示装置、画素回路およびその駆動方法 - Google Patents
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- WO2009142033A1 WO2009142033A1 PCT/JP2009/052477 JP2009052477W WO2009142033A1 WO 2009142033 A1 WO2009142033 A1 WO 2009142033A1 JP 2009052477 W JP2009052477 W JP 2009052477W WO 2009142033 A1 WO2009142033 A1 WO 2009142033A1
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3233—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
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- G09G2300/0421—Structural details of the set of electrodes
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- G09G2300/0861—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
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- G09G2310/0254—Control of polarity reversal in general, other than for liquid crystal displays
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- G09G2320/0626—Adjustment of display parameters for control of overall brightness
Definitions
- the present invention relates to a display device, and more particularly to a current-driven display device such as an organic EL display or FED, a pixel circuit of the display device, and a driving method of the pixel circuit.
- a current-driven display device such as an organic EL display or FED
- a pixel circuit of the display device and a driving method of the pixel circuit.
- the organic EL element included in the organic EL display emits light with higher luminance as the applied voltage is higher and the flowing current is larger.
- the relationship between the luminance and voltage of the organic EL element easily varies under the influence of driving time and ambient temperature. For this reason, when a voltage control type driving method is applied to the organic EL display, it becomes very difficult to suppress variations in luminance of the organic EL element.
- the luminance of the organic EL element is substantially proportional to the current, and this proportional relationship is not easily influenced by external factors such as the ambient temperature. Therefore, it is preferable to apply a current control type driving method to the organic EL display.
- the pixel circuit and the drive circuit of the display device are configured using TFTs (Thin Film Transistors) made of amorphous silicon, low-temperature polycrystalline silicon, CG (Continuous Grain) silicon, or the like.
- TFTs Thin Film Transistors
- CG Continuous Grain
- a method for compensating for variations in TFT characteristics includes a current programming method in which the amount of current flowing in the driving TFT is controlled by a current signal, and a voltage programming method in which the amount of current is controlled by a voltage signal. It is roughly divided into If the current programming method is used, variations in threshold voltage and mobility can be compensated, and if the voltage programming method is used, only variations in threshold voltage can be compensated.
- the influence of parasitic capacitance is set during setting of a current signal.
- the influence of parasitic capacitance and the like is slight, and the circuit design is relatively easy.
- the influence of the mobility variation on the current amount is smaller than the influence of the threshold voltage variation on the current amount, and the mobility variation can be suppressed to some extent in the TFT manufacturing process. Therefore, even with a display device to which the voltage program method is applied, sufficient display quality can be obtained.
- FIG. 8 is a circuit diagram of a pixel circuit described in Non-Patent Document 4.
- a pixel circuit 900 shown in FIG. 8 includes a driving TFT 910, switching TFTs 911 to 913, a capacitor 921, and an organic EL element 930. All of the TFTs included in the pixel circuit 900 are n-channel type.
- a switching TFT 913, a driving TFT 910, and an organic EL element 930 are provided in series between a power supply wiring Vp having a potential VDD and a cathode CTD of the organic EL element 930.
- a switching TFT 911 is provided between the source terminal of the driving TFT 910 and the data line Sj
- a switching TFT 912 is provided between the gate terminal and the drain terminal of the driving TFT 910
- the gate terminal of the driving TFT 910 A capacitor 921 is provided between the power supply wiring Vp.
- the gate terminals of the switching TFTs 911 and 912 are both connected to the control wiring SLT, and the gate terminal of the switching TFT 913 is connected to the control wiring TNO.
- FIG. 9 is a timing chart of the pixel circuit 900.
- the potential of the control wiring SLT changes to a high level.
- the switching TFTs 911 and 912 are turned on, and the data potential Vda is applied from the data line Sj to the source terminal of the driving TFT 910 via the switching TFT 911.
- the potential of the cathode CTD of the organic EL element 930 also changes to a high level. Therefore, a reverse bias voltage is applied between the anode and the cathode of the organic EL element 930, and the organic EL element 930 enters a non-light emitting state.
- the switching TFTs 912 and 913 are both conductive from time t1 to time t2, the gate potential of the driving TFT 910 becomes equal to the potential VDD of the power supply wiring Vp.
- the potential of the control wiring TNO changes to a low level.
- the switching TFT 913 becomes non-conductive, and a current flows from the gate terminal of the driving TFT 910 (and the drain terminal short-circuited thereto) to the data line Sj via the driving TFT 910 and the switching TFT 911,
- the gate potential of the driving TFT 910 gradually decreases.
- the driving TFT 910 is turned off.
- the potential difference between the electrodes of the capacitor 921 becomes ⁇ Vp ⁇ (Vda + Vth) ⁇ . Thereafter, this potential difference is held in the capacitor 921.
- the potential of the control wiring TNO changes to a high level, and the potential of the control wiring SLT changes to a low level. For this reason, the switching TFTs 911 and 912 are turned off, and the switching TFT 913 is turned on. Since the capacitor 921 holds the potential difference ⁇ Vp ⁇ (Vda + Vth) ⁇ , the gate potential of the driving TFT 910 remains (Vda + Vth) after time t3. At time t3, the potential of the cathode CTD of the organic EL element 930 changes to a low level.
- a current corresponding to the potential Vda (equal to the data potential) obtained by subtracting the threshold voltage Vth of the driving TFT 910 from the gate potential (Vda + Vth) of the driving TFT 910 flows from the driving TFT 910 to the organic EL element 930,
- the EL element 930 emits light with luminance corresponding to the current.
- the current flowing from the driving TFT 910 to the organic EL element 930 after time t3 is determined by the data potential Vda and is not affected by the threshold voltage Vth of the driving TFT 910. Therefore, according to the display device including the pixel circuit 900, even when the threshold voltage Vth of the driving TFT 910 varies, a current corresponding to the data potential Vda and the threshold voltage Vth is supplied to the organic EL element 930, and the organic EL element The 930 can emit light with a desired luminance. “4.0-in. TFT-OLED Displays and a Novel Digital Driving Method”, SID'00 Digest, pp.
- the organic EL element is used in a period (period from time t1 to t3) in which the gate-source voltage of the driving TFT 910 matches the threshold voltage Vth of the driving TFT 910. It is necessary to set the potential of the cathode 930 of 930 to a high level.
- a general active matrix display device includes only one cathode common to all display elements. Therefore, even when the pixel circuit 900 is used, a display device (hereinafter referred to as a first display device) provided with only one cathode common to all the organic EL elements 930 can be considered.
- the first display device when the data potential Vda is written to a certain pixel circuit 900, a reverse bias voltage is applied to all the organic EL elements 930 in the display device.
- the element 930 does not emit light during this period. For this reason, the first display device has a problem that a sufficient light emission duty ratio cannot be obtained and display quality is lowered.
- a display device in which the cathode CTD of the organic EL element 930 is provided for each row of pixel circuits (a display device in which the same number of cathode CTDs as the control wiring SLT is provided; hereinafter referred to as a second display device) Can think.
- a display device in which the same number of cathode CTDs as the control wiring SLT is provided hereinafter referred to as a second display device
- the second display device has a problem that one extra process for producing the organic EL element 930 is added and the manufacturing cost is increased.
- the cathode CTD of the organic EL element 930 is patterned, there is a problem that the aperture ratio is lowered and the screen becomes dark.
- an object of the present invention is to provide a display device with high display quality and low cost, which has a high light emission duty ratio and does not require patterning of one electrode of an electro-optic element.
- a first aspect of the present invention is a current-driven display device, A plurality of pixel circuits arranged corresponding to the intersections of the plurality of scanning lines and the plurality of data lines; A scanning signal output circuit for selecting a pixel circuit to be written using the scanning line; A display signal output circuit for applying a potential corresponding to display data to the data line;
- the pixel circuit includes: A driving element that is provided on a path connecting the first wiring and the second wiring and has a control terminal, a first terminal, and a second terminal, and controls a current flowing through the path; An electro-optic element that is connected to the first terminal of the driving element and is provided in series with the driving element on the path, and emits light with luminance according to a current flowing through the path; A first switching element provided between a first terminal of the driving element and the data line; A second switching element provided between a control terminal and a second terminal of the drive element; A third switching element provided between the second terminal of the driving element and the first wiring; A capacitor provided between a control terminal of
- the pixel circuit further includes a fourth switching element provided between a control terminal of the driving element and a fourth wiring.
- control terminal of the fourth switching element is connected to the fourth wiring.
- the fourth wiring is provided with a potential at which the driving element becomes conductive.
- the first and second switching elements are controlled to be in a conductive state, and the third switching element is controlled to be in a non-conductive state.
- the scanning signal output circuit has a function of adjusting a change timing of a potential of the third wiring.
- the scanning signal output circuit has a function of adjusting a change timing of a potential applied to a control terminal of the third switching element.
- the electro-optical element is composed of an organic EL element.
- a pixel circuit disposed in a current-driven display device in a plurality corresponding to each intersection of a plurality of scanning lines and a plurality of data lines,
- a driving element that is provided on a path connecting the first wiring and the second wiring and has a control terminal, a first terminal, and a second terminal, and controls a current flowing through the path;
- An electro-optic element that is connected to the first terminal of the driving element and is provided in series with the driving element on the path, and emits light with luminance according to a current flowing through the path;
- a first switching element provided between a first terminal of the driving element and the data line;
- a second switching element provided between a control terminal and a second terminal of the drive element;
- a third switching element provided between the second terminal of the driving element and the first wiring;
- a capacitor provided between a control terminal of the drive element and a third wiring;
- a fourth switching element provided between the control terminal of the driving element and a fourth wiring is further provided.
- An eleventh aspect of the present invention is the tenth aspect of the present invention,
- the control terminal of the fourth switching element is connected to the fourth wiring.
- a twelfth aspect of the present invention is a pixel circuit driving method in which a plurality of pixel circuits are arranged in a current-driven display device corresponding to the intersections of a plurality of scanning lines and a plurality of data lines.
- a driving element provided on a path connecting the first wiring and the second wiring, the pixel circuit having a control terminal, a first terminal, and a second terminal, and controlling a current flowing through the path;
- An electro-optic element connected in series to the drive element on the path connected to the first terminal of the drive element and emitting light with a luminance according to a current flowing through the path; and a first of the drive element
- a first switching element provided between the terminal and the data line; a second switching element provided between the control terminal and the second terminal of the driving element; and a second switching element of the driving element.
- a third switching element provided between the terminal and the first wiring, and a capacitor provided between the control terminal of the driving element and the third wiring,
- the first and second switching elements are controlled to be in a conductive state
- the third switching element is controlled to be in a non-conductive state
- the data line changes according to display data
- the electro-optical element is changed. Applying a potential at which the applied voltage is equal to or lower than the light emission threshold voltage; Changing the potential of the third wiring in two stages; Controlling the first and second switching elements to a non-conducting state and the third switching element to a conducting state.
- a thirteenth aspect of the present invention is the twelfth aspect of the present invention,
- the pixel circuit further includes a fourth switching element provided between a control terminal of the driving element and a fourth wiring
- a potential at which the driving element becomes conductive is applied to the fourth wiring, and the first and second switching elements are in a conductive state and the third switching element is in a non-conductive state.
- the method further includes the step of controlling the fourth switching element to a conductive state.
- the electro-optic element since the data line is given a potential at which the voltage applied to the electro-optic element is equal to or lower than the light emission threshold voltage, the electro-optic element is simply written to the pixel circuit. Does not emit light, and the electro-optic element emits light after the potential of the third wiring changes. Further, if the second switching element is controlled to be in a conductive state and the third switching element is controlled to be in a non-conductive state, a threshold voltage can be applied between the control terminal of the driving element and the first terminal, In addition, by changing the potential of the third wiring, the electro-optical element can emit light with a desired luminance regardless of the threshold voltage of the driving element.
- the electro-optic element when the potential corresponding to the display data is written in the pixel circuit while compensating for the variation in the threshold voltage of the driving element, the electro-optic element is brought into a non-light emitting state while the potential of the second wiring is fixed. be able to. For this reason, the electro-optical elements of other pixel circuits continue to emit light while writing to a certain pixel circuit, so the electro-optical elements of other pixel circuits emit light while writing to a certain pixel circuit. The light emission duty ratio becomes higher and the display quality becomes higher than when it disappears. In addition, since it is not necessary to divide and control the potential of the second wiring, it is not necessary to pattern the electrode on the second wiring side of the electro-optic element, and the cost of the display device is reduced accordingly.
- the scanning signal output circuit that changes the potential of the third wiring in two stages can be easily configured. Therefore, it is possible to obtain a display device with high display quality and low cost, which has a high light emission duty ratio and does not require patterning of one electrode of the electro-optic element.
- the potential of the first wiring is applied to the control terminal of the drive element by applying a suitable potential to the fourth wiring and controlling the fourth switching element to the conductive state.
- a threshold voltage can be applied between the control terminal of the drive element and the first terminal without applying the voltage. Thereby, the power consumption of the display device can be reduced.
- the control terminal of the fourth switching element by connecting the control terminal of the fourth switching element to the same wiring as the other terminals, one wiring is reduced, and the aperture ratio and yield of the display device are increased. Can do.
- the electro-optical element by controlling the second switching element to the conductive state and the third switching element to the non-conductive state, between the control terminal of the drive element and the first terminal A threshold voltage can be applied. After that, by applying a potential at which the driving element becomes conductive to the third wiring, the electro-optical element can emit light with desired luminance regardless of the threshold voltage of the driving element.
- the moving image which is a defect of the display device which performs the hold type display by adjusting the light emission duty ratio by adjusting the change timing of the potential of the third wiring in the scanning signal output circuit. Blur can be eliminated.
- a display device that performs hold-type display by adjusting a light emission duty ratio by adjusting a change timing of a potential applied to a control terminal of a third switching element in a scanning signal output circuit. It is possible to eliminate the motion blur that is a drawback of the above.
- a high display quality and low cost organic EL display having a high light emission duty ratio and requiring no patterning of the cathode of the organic EL element can be configured.
- the pixel circuit included in the display device according to the first to third aspects of the present invention is configured, and using this, the light emission duty ratio is high, and the electro-optics A display device with high display quality and low cost which does not require patterning of one electrode of the element can be obtained.
- the light emission duty ratio is increased.
- the display quality can be increased.
- a potential at which the drive element becomes conductive is applied to the fourth wiring, and the fourth switching element is controlled to be in the conductive state, whereby the potential of the first wiring is set to the drive element.
- the threshold voltage can be applied between the control terminal of the drive element and the first terminal in a short time without being applied to the control terminal. As a result, the power consumption of the display device can be reduced and a display device with high resolution can be configured.
- FIG. 1 is a circuit diagram of a pixel circuit included in a display device according to a first embodiment of the present invention.
- 3 is a timing chart of the pixel circuit shown in FIG. It is a circuit diagram of an inverter.
- the display device includes a pixel circuit including an electro-optical element, a driving element, a capacitor, and a plurality of switching elements.
- the switching element can be composed of a low-temperature polysilicon TFT, a CG silicon TFT, an amorphous silicon TFT, or the like. Since the structure and manufacturing process of these TFTs are known, the description thereof is omitted here.
- An organic EL element is used as the electro-optical element. Since the configuration of the organic EL element is also known, its description is omitted here.
- FIG. 1 is a block diagram showing a configuration of a display device according to the first and second embodiments of the present invention.
- a display device 10 shown in FIG. 1 includes a plurality of pixel circuits Aij (i is an integer of 1 to n, j is an integer of 1 to m), a display control circuit 11, a gate driver circuit 12, and a source driver circuit 13. It has.
- the display device 10 is provided with a plurality of scanning lines Gi arranged in parallel to each other and a plurality of data lines Sj arranged in parallel to each other so as to be orthogonal to the scanning lines Gi.
- the pixel circuits Aij are arranged in a matrix corresponding to the intersections of the scanning lines Gi and the data lines Sj.
- a plurality of control wirings (Ri, Ui, Wi, etc .; not shown) are arranged in parallel to the scanning lines Gi.
- the power supply wiring Vp and the common cathode Vcom are arranged in the arrangement region of the pixel circuit Aij, and the power supply wiring Vref may be arranged in some embodiments.
- the scanning line Gi and the control wiring are connected to the gate driver circuit 12, and the data line Sj is connected to the source driver circuit 13.
- the display control circuit 11 outputs a timing signal OE, a start pulse YI, and a clock YCK to the gate driver circuit 12, and outputs a start pulse SP, a clock CLK, display data DA, and a latch pulse LP to the source driver circuit 13. To do.
- the gate driver circuit 12 includes a shift register circuit, a logical operation circuit, and a buffer (all not shown).
- the shift register circuit sequentially transfers the start pulse YI in synchronization with the clock YCK.
- the logical operation circuit performs a logical operation between the pulse output from each stage of the shift register circuit and the timing signal OE.
- the output of the logical operation circuit is given to the corresponding scanning line Gi and control wiring via the buffer.
- the gate driver circuit 12 functions as a scanning signal output circuit that selects a pixel circuit to be written using the scanning line Gi.
- the source driver circuit 13 includes an m-bit shift register 21, a register 22, a latch circuit 23, and m D / A converters 24.
- the shift register 21 includes m 1-bit registers connected in cascade. The shift register 21 sequentially transfers the start pulse SP in synchronization with the clock CLK, and outputs a timing pulse DLP from each stage register. Display data DA is supplied to the register 22 in accordance with the output timing of the timing pulse DLP.
- the register 22 stores display data DA according to the timing pulse DLP. When the display data DA for one row is stored in the register 22, the display control circuit 11 outputs a latch pulse LP to the latch circuit 23. When the latch circuit 23 receives the latch pulse LP, the latch circuit 23 holds the display data stored in the register 22.
- One D / A converter 24 is provided for each data line Sj.
- the D / A converter 24 converts the display data held in the latch circuit 23 into an analog signal voltage, and supplies it to the corresponding data line Sj.
- the source driver circuit 13 functions as a display signal output circuit that applies a potential corresponding to display data to the data line Sj.
- the source driver circuit 13 performs line-sequential scanning for simultaneously supplying a potential corresponding to display data for one row to a pixel circuit connected to one scanning line. Instead, dot sequential scanning may be performed in which a potential corresponding to display data is sequentially supplied to each pixel circuit. Since the configuration of the source driver circuit that performs dot sequential scanning is known, the description thereof is omitted here.
- the driving TFT, the switching TFT, and the organic EL element included in the pixel circuit Aij function as a driving element, a switching element, and an electro-optical element, respectively.
- the power supply wiring Vp corresponds to the first wiring
- the common cathode Vcom corresponds to the second wiring.
- FIG. 2 is a circuit diagram of a pixel circuit included in the display device according to the first embodiment of the present invention.
- the pixel circuit 100 shown in FIG. 2 includes a driving TFT 110, switching TFTs 111 to 113, a capacitor 121, and an organic EL element 130. All of the TFTs included in the pixel circuit 100 are n-channel type.
- the pixel circuit 100 is connected to the power supply wiring Vp, the common cathode Vcom, the scanning line Gi, the control wiring Ri, Ui, and the data line Sj.
- constant potentials VDD and VSS are applied to the power supply wiring Vp and the common cathode Vcom, respectively.
- the common cathode Vcom is a cathode common to all the organic EL elements 130 in the display device.
- the terminals of the driving TFT 110 described as G, S, and D in FIG. 2 are called a gate terminal, a source terminal, and a drain terminal, respectively.
- the lower one of the two current input / output terminals is called a source terminal, and the higher applied voltage is called a drain terminal.
- the lower one of the two current input / output terminals is referred to as a drain terminal, and the higher applied voltage is referred to as a source terminal.
- the terminal name is changed according to the magnitude relation of the voltage, the explanation becomes complicated, so the magnitude relation of the voltage is reversed, and even when the two current input / output terminals should be called with the opposite names,
- the terminals are referred to by the names shown for convenience.
- the n-channel type is used for all TFTs, but the p-channel type may be used for the switching TFTs.
- the low level potential corresponds to the conductive state and the high level potential corresponds to the nonconductive state.
- the conductive potential and the nonconductive state potential are opposite to those in the case where the n-channel type is used for the switching TFT. Become.
- the above points are the same in the second embodiment.
- a switching TFT 113 In the pixel circuit 100, a switching TFT 113, a driving TFT 110, and an organic EL element 130 are provided in series on the path connecting the power supply wiring Vp and the common cathode Vcom in this order from the power supply wiring Vp side.
- a switching TFT 111 is provided between the source terminal of the driving TFT 110 and the data line Sj
- a switching TFT 112 is provided between the gate terminal and the drain terminal of the driving TFT 110
- the gate terminal of the driving TFT 110 A capacitor 121 is provided between the control wiring Ui.
- the gate terminals of the switching TFTs 111 and 112 are both connected to the scanning line Gi, and the gate terminal of the switching TFT 113 is connected to the control wiring Ri.
- the operation of the pixel circuit 100 is controlled by a gate driver circuit 12 and a source driver circuit 13 that operate based on a signal supplied from the display control circuit 11.
- FIG. 3 is a timing chart of the pixel circuit 100.
- FIG. 3 shows changes in potentials of the scanning line Gi, the control wirings Ri and Ui, and the data line Sj.
- the reason why the organic EL element 130 is controlled to be in a non-light emitting state during the period when the voltage of the scanning line Gi is at a high level is that when the organic EL element 130 emits light during this period, a black display is performed. This is because the brightness increases by that amount and the contrast of the screen decreases.
- the potential of the scanning line Gi is controlled to a low level
- the potential of the control wiring Ri is controlled to a high level
- the potential of the control wiring Ui is controlled to a relatively high potential V1. Therefore, the switching TFTs 111 and 112 are in a non-conductive state, and the switching TFT 113 is in a conductive state.
- the driving TFT 110 is in a conductive state, a current flows from the power supply wiring Vp to the organic EL element 130 via the switching TFT 113 and the driving TFT 110, and the organic EL element 130 emits light with a predetermined luminance.
- the potential of the scanning line Gi changes to a high level, and a new data potential Vda is applied to the data line Sj.
- the switching TFTs 111 and 112 become conductive, and the data potential Vda is applied from the data line Sj to the source terminal of the driving TFT 110 via the switching TFT 111.
- the data potential Vda applied at this time is determined so that the organic EL element 130 is in a non-light emitting state.
- the data potential Vda is determined such that the difference from the potential VSS is equal to or less than the emission threshold voltage Vth_oled. .
- Vth_oled ⁇ Vda ⁇ VSS (1)
- the gate and drain of the driving TFT 110 are short-circuited, and the potential VDD is applied to the gate terminal and the drain terminal of the driving TFT 110 from the power supply wiring Vp. Therefore, the gate-source voltage Vgs of the driving TFT 110 is expressed by the following equation (2).
- Vgs VDD ⁇ Vda (2)
- the potential of the control wiring Ui changes to a relatively low potential V2.
- the potential of the control wiring Ri changes to a low level.
- the switching TFT 113 becomes non-conductive, current flows from the gate terminal of the driving TFT 110 (and the drain terminal short-circuited thereto) to the source terminal, and the gate potential of the driving TFT 110 gradually decreases.
- the gate-source voltage of the driving TFT 110 becomes equal to the threshold voltage Vth of the driving TFT 110 (that is, when the gate potential becomes (Vda + Vth))
- the driving TFT 110 becomes non-conductive and is driven. Thereafter, the gate potential of the TFT 110 does not decrease.
- the driving TFT 110 is in a state in which the threshold voltage Vth is applied between the gate and the source regardless of the threshold voltage Vth.
- the potential difference between the electrodes of the capacitor 121 is (Vda + Vth ⁇ V2). Thereafter, this potential difference is held in the capacitor 121.
- the potential of the scanning line Gi changes to a low level. For this reason, the switching TFTs 111 and 112 become non-conductive.
- the potential of the control wiring Ui changes from V2 to V1. Since the control wiring Ui and the gate terminal of the driving TFT 110 are connected via the capacitor 121, when the potential of the control wiring Ui changes, the gate potential of the driving TFT 110 changes by the same amount (V1-V2). For this reason, the gate potential Vg of the driving TFT 110 is expressed by the following equation (3).
- Vg Vda + Vth + V1-V2 (3)
- the potential of the control wiring Ri changes to a high level. For this reason, the switching TFT 113 becomes conductive, and the potential VDD is applied to the drain terminal of the driving TFT 110 from the power supply wiring Vp. Further, since the potential difference (Vda + Vth ⁇ V2) is held in the capacitor 121, the gate potential of the driving TFT 110 remains (Vda + Vth + V1 ⁇ V2) after time t6. Therefore, a current corresponding to a voltage (Vda + V1-V2) obtained by subtracting the threshold voltage Vth of the driving TFT 110 from the gate potential (Vda + Vth + V1-V2) of the driving TFT 110 flows from the power supply wiring Vp to the common cathode Vcom.
- the element 130 emits light with a luminance corresponding to the current.
- the EL element 130 can emit light with desired luminance.
- the gate driver circuit 12 changes the potential of the control wiring Ui in two steps (V1 and V2).
- the inverter circuit shown in FIG. 4 is provided as a buffer circuit at the final stage of the gate driver circuit 12.
- the inverter circuit shown in FIG. 4 changes the potential of the control wiring Ui in two steps according to the input signal IN.
- the display device includes a gate driver circuit 12 that changes the potential of the control wiring Ui in two stages. Such a gate driver circuit can be easily configured.
- the display device includes the plurality of pixel circuits 100, the gate driver circuit 12, and the source driver circuit 13.
- the pixel circuit 100 includes the driving TFT 110, the switching TFTs 111 to 113, and the capacitor 121. And an organic EL element 130.
- the source driver circuit 13 gives a potential at which the voltage applied to the organic EL element 130 is equal to or lower than the light emission threshold voltage Vth_oled to the data line Sj, and the gate driver circuit 12 sets the potential of the control wiring Ui in two stages (V1). And V2).
- the data line Sj is given a potential at which the voltage applied to the organic EL element 130 is equal to or lower than the light emission threshold voltage Vth_oled. Therefore, the organic EL element 130 emits light only by writing the potential of the data line Sj to the pixel circuit 100. Instead, the organic EL element 130 emits light after the potential of the control wiring Ui changes to V1. Further, the threshold voltage Vth can be applied between the gate and the source of the driving TFT 110 by controlling the switching TFT 112 to be conductive and the switching TFT 113 to be non-conductive.
- the driving TFT 110 can emit light with a desired luminance regardless of the threshold voltage Vth of the driving TFT 110 by applying a potential at which the driving TFT 110 becomes conductive to the control wiring Ui.
- the organic EL element 130 is brought into a non-light emitting state while the potential of the common cathode Vcom is fixed. be able to.
- the organic EL elements 130 of the other pixel circuits 100 continue to emit light while writing to a certain pixel circuit 100. Therefore, while writing to a certain pixel circuit, the organic EL elements of other pixel circuits As compared with a display device that stops emitting light, the light emission duty ratio becomes higher and the display quality becomes higher. Further, since it is not necessary to divide and control the potential of the common cathode Vcom, it is not necessary to pattern the cathode of the organic EL element 130, and the cost of the display device is accordingly reduced. Further, the gate driver circuit 12 that changes the potential of the control wiring Ui in two steps can be easily configured. Therefore, it is possible to obtain a display device (organic EL display) with high display quality and low cost, which has a high light emission duty ratio and does not require patterning of the cathode of the organic EL element 130.
- the display device can be manufactured easily and with high performance.
- all the switching elements in the driving TFT 110 and the pixel circuit 100 with n-channel transistors, all the transistors can be manufactured by the same process using the same mask, and the cost of the display device can be reduced.
- the same channel type transistor can be arranged closer to different channel type transistors, more transistors can be arranged in the same area.
- the gate terminals of the switching TFTs 111 and 112 are connected to the same wiring (scanning line Gi), but the gate terminals of the switching TFTs 111 and 112 are connected to different control wirings,
- the potential of the control wiring may be changed at substantially the same timing (first modification).
- the current that flows to the source terminal of the driving TFT 110 from time t1 to time t4 is the resistance component of the organic EL element 130 and the resistance when the switching TFT 111 is conductive. Depending on the component, it flows to the organic EL element 130 and the switching TFT 111. In general, the lifetime of the organic EL element becomes shorter as a larger amount of current flows. Therefore, in order to prevent a current from flowing through the organic EL element 130, the data potential Vda may be set to be equal to or lower than the potential VSS of the common cathode Vcom (second modification). This is expressed by the following equation (5). Vda ⁇ VSS (5)
- the anode and the cathode of the organic EL element 130 are either at the same potential, or a reverse bias voltage is applied to the organic EL element 130. Therefore, current can be prevented from flowing through the organic EL element 130 from time t1 to time t4 (while the switching TFT 111 is in a conductive state), and the life of the organic EL element 130 can be extended.
- the potential of the control line Ui is lowered (changed from V1 to V2) after the potential of the scanning line Gi is changed to high level, but the potential of the scanning line Gi is changed to high level. Prior to the change, the potential of the control wiring Ui may be lowered (third modification). According to this method, even when the number of scanning lines Gi is large and the time during which the potential of the scanning line Gi is at a high level is short, variations in the threshold voltage Vth of the driving TFT 110 can be compensated. However, when this method is used, a forward bias voltage is applied to the organic EL element 130, the organic EL element 130 emits light unnecessarily, and the contrast of the screen may be lowered. Therefore, as shown in FIG. 3, it is more preferable to lower the potential of the control wiring Ui after changing the potential of the scanning line Gi to the high level.
- the gate driver circuit 12 may be provided with a function of adjusting the timing (time t5 in FIG. 3) for increasing the potential of the control wiring Ui (fourth modification).
- the timing time t5 in FIG. 3
- the length of the light emission period of the organic EL element 130 can be adjusted, and the light emission duty ratio of the organic EL element 130 can be adjusted. Therefore, it is possible to eliminate moving image blur, which is a drawback of a display device that performs hold-type display, such as an organic EL display.
- the gate driver circuit 12 may be provided with a function of adjusting the timing (time t6 in FIG. 3) at which the potential of the control wiring Ri is set to the high level (fifth modification).
- the timing time t6 in FIG. 3
- the length of the light emission period of the organic EL element 130 can be adjusted, and the light emission duty ratio of the organic EL element 130 can be adjusted. Therefore, the same effect as the display device according to the fourth modification can be obtained.
- FIG. 5 is a circuit diagram of a pixel circuit included in a display device according to the second embodiment of the present invention.
- a pixel circuit 200 shown in FIG. 5 includes a driving TFT 110, switching TFTs 111 to 113, 214, a capacitor 121, and an organic EL element 130. All of the TFTs included in the pixel circuit 200 are n-channel type.
- the same elements as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.
- the pixel circuit 200 adds a power supply wiring Vref and a control wiring Wi to the pixel circuit 100 according to the first embodiment, and a switching TFT 214 is provided between the power supply wiring Vref and the gate terminal of the driving TFT 110. A change is made to connect the gate terminal of the switching TFT 214 to the control wiring Wi. A constant initial potential Vini is applied to the power supply wiring Vref.
- FIG. 6 is a timing chart of the pixel circuit 200.
- FIG. 6 shows changes in potentials of the scanning line Gi, the control wirings Ri, Ui, Wi, and the data line Sj.
- the potential of the control wiring Wi Prior to time t4, the potential of the control wiring Wi is controlled to a low level. For this reason, the switching TFT 214 is in a non-conductive state, and the pixel circuit 200 operates in the same manner as the pixel circuit 100.
- the threshold voltage Vth needs to be applied between the gate and the source of the driving TFT 110 from time t3 to time t4. However, in the pixel circuit 200, this is not necessary.
- the potential of the control wiring Wi changes to a high level.
- the switching TFT 214 becomes conductive, and the initial potential Vini is applied from the power supply wiring Vref to the gate terminal and the drain terminal of the driving TFT 110 via the switching TFT 214.
- the initial potential Vini is determined so that the driving TFT 110 becomes conductive.
- the initial potential Vini is determined so that the difference from the source potential Vda of the driving TFT 110 is equal to or higher than the threshold voltage Vth of the driving TFT 110 in all the pixel circuits 200. This is expressed by the following equation (6).
- the potential of the control wiring Wi changes to a low level. For this reason, the switching TFT 214 becomes non-conductive, current flows from the gate terminal of the driving TFT 110 (and the drain terminal short-circuited thereto) to the source terminal, and the gate potential of the driving TFT 110 gradually decreases.
- the driving TFT 110 becomes equal to the threshold voltage Vth of the driving TFT 110
- the driving TFT 110 becomes non-conductive, and the gate potential of the driving TFT 110 does not decrease thereafter.
- the driving TFT 110 is in a state in which the threshold voltage Vth is applied between the gate and the source regardless of the threshold voltage Vth.
- the potential difference between the electrodes of the capacitor 121 is (Vda + Vth ⁇ V2). Thereafter, this potential difference is held in the capacitor 121.
- the pixel circuit 200 operates in the same manner as after the time t4 of the pixel circuit 100.
- the pixel circuit 200 includes the switching TFT 214 between the gate terminal of the driving TFT 110 and the power supply wiring Vref, and the power supply wiring Vref is given a potential at which the driving TFT 110 becomes conductive. Therefore, by controlling the switching TFT 214 to be in a conductive state, the threshold voltage Vth between the gate and source of the driving TFT 110 can be applied without applying the potential VDD of the power supply wiring Vp to the gate terminal of the driving TFT 110. it can. Therefore, the display device according to the present embodiment can reduce power consumption.
- the time until the threshold voltage Vth is applied between the gate and the source of the driving TFT 110 is shortened, and a display device with high resolution is configured. It becomes possible.
- the display device according to the second embodiment may also be configured as the first to fifth modifications, as in the first embodiment.
- the display device of the present invention may include a pixel circuit shown in FIG.
- the pixel circuit 250 illustrated in FIG. 7 is obtained by changing the pixel circuit 200 so that one end of the switching TFT 214 is connected to the control wiring Wi and the power supply wiring Vref is deleted. In this manner, by connecting the gate terminal of the switching TFT 214 to the same wiring as the other terminals, one wiring can be reduced, and the aperture ratio and the yield of the display device can be increased.
- the pixel circuit includes an organic EL element as an electro-optical element.
- the pixel circuit is an electro-optical element other than an organic EL element such as a semiconductor LED (Light Emitting Diode) or a light emitting unit of an FED.
- the current drive type electro-optical element may be included.
- the pixel circuit is a MOS transistor (herein referred to as a MOS transistor including a silicon gate MOS structure) formed on an insulating substrate such as a glass substrate as a driving element for the electro-optical element. TFT was included.
- the pixel circuit is not limited to this, and the pixel circuit has an arbitrary control voltage (threshold voltage) that changes the output current according to the control voltage applied to the current control terminal as the driving element of the electro-optical element and the output current becomes zero
- a voltage-controlled element may be included.
- a general insulated gate field effect transistor including, for example, a MOS transistor formed on a semiconductor substrate can be used as the drive element of the electro-optic element.
- an insulated gate field effect transistor as the driving element, it is possible to prevent a current flowing through the driving element from flowing into the electro-optical element when compensating for variations in the threshold voltage of the driving element. Accordingly, unnecessary light emission of the electro-optical element can be prevented, the contrast of the screen can be increased, and deterioration of the electro-optical element can be suppressed.
- the pixel circuit includes a TFT as a switching element.
- the pixel circuit includes a general insulated gate field effect transistor including a MOS transistor formed on a semiconductor substrate as the switching element. May be included.
- the display device of the present invention has a high light emission duty ratio, does not require patterning of one electrode of the electro-optic element, and has an effect of high display quality and low cost. Therefore, a current drive type such as an organic EL display or FED is provided. It can utilize for the various display apparatus provided with this display element.
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Abstract
Description
"4.0-in. TFT-OLED Displays and a Novel Digital Driving Method"、SID'00 Digest、pp. 924-927、半導体エネルギー研究所 "Continuous Grain Silicon Technology and Its Applications for Active Matrix Display"、AM-LCD 2000、pp. 25-28、半導体エネルギー研究所 "Polymer Light-Emitting Diodes for Use in Flat Panel Display"、AM-LCD' 01、pp. 211-214、半導体エネルギー研究所 "A new a-Si:H Thin-Film Transistor Pixel Circuit for Active-Matrix Organic Light-Emitting Diodes" 、Electron Device Letters、IEEE、Volume 24、Issue 9、pp. 583-585、Korea Advanced Institute of Science and Technology
複数の走査線と複数のデータ線の各交差点に対応して配置された複数の画素回路と、
前記走査線を用いて、書き込み対象の画素回路を選択する走査信号出力回路と、
前記データ線に対して、表示データに応じた電位を与える表示信号出力回路とを備え、
前記画素回路は、
第1の配線と第2の配線とを結ぶ経路上に設けられ、制御端子、第1の端子および第2の端子を有し、前記経路を流れる電流を制御する駆動素子と、
前記駆動素子の第1の端子に接続して前記経路上に前記駆動素子と直列に設けられ、前記経路を流れる電流に応じた輝度で発光する電気光学素子と、
前記駆動素子の第1の端子と前記データ線との間に設けられた第1のスイッチング素子と、
前記駆動素子の制御端子と第2の端子との間に設けられた第2のスイッチング素子と、
前記駆動素子の第2の端子と前記第1の配線との間に設けられた第3のスイッチング素子と、
前記駆動素子の制御端子と第3の配線との間に設けられたコンデンサとを含み、
前記表示信号出力回路は、前記データ線に対して、前記電気光学素子への印加電圧が発光閾値電圧以下となる電位を与え、
前記走査信号出力回路は、前記第3の配線の電位を2段階に変化させることを特徴とする。
前記画素回路は、前記駆動素子の制御端子と第4の配線との間に設けられた第4のスイッチング素子をさらに含む。
前記第4のスイッチング素子の制御端子は、前記第4の配線に接続されていることを特徴とする。
前記第4の配線には、前記駆動素子が導通状態となる電位が与えられることを特徴とする。
前記画素回路に対する書き込み時には、前記第1および第2のスイッチング素子は導通状態に、前記第3のスイッチング素子は非導通状態に制御されることを特徴とする。
前記走査信号出力回路は、前記第3の配線の電位の変化タイミングを調整する機能を有することを特徴とする。
前記走査信号出力回路は、前記第3のスイッチング素子の制御端子に与える電位の変化タイミングを調整する機能を有することを特徴とする。
前記電気光学素子は有機EL素子で構成されていることを特徴とする。
第1の配線と第2の配線とを結ぶ経路上に設けられ、制御端子、第1の端子および第2の端子を有し、前記経路を流れる電流を制御する駆動素子と、
前記駆動素子の第1の端子に接続して前記経路上に前記駆動素子と直列に設けられ、前記経路を流れる電流に応じた輝度で発光する電気光学素子と、
前記駆動素子の第1の端子と前記データ線との間に設けられた第1のスイッチング素子と、
前記駆動素子の制御端子と第2の端子との間に設けられた第2のスイッチング素子と、
前記駆動素子の第2の端子と前記第1の配線との間に設けられた第3のスイッチング素子と、
前記駆動素子の制御端子と第3の配線との間に設けられたコンデンサとを備える。
前記駆動素子の制御端子と第4の配線との間に設けられた第4のスイッチング素子をさらに備える。
前記第4のスイッチング素子の制御端子は、前記第4の配線に接続されていることを特徴とする。
前記画素回路が、第1の配線と第2の配線とを結ぶ経路上に設けられ、制御端子、第1の端子および第2の端子を有し、前記経路を流れる電流を制御する駆動素子と、前記駆動素子の第1の端子に接続して前記経路上に前記駆動素子と直列に設けられ、前記経路を流れる電流に応じた輝度で発光する電気光学素子と、前記駆動素子の第1の端子と前記データ線との間に設けられた第1のスイッチング素子と、前記駆動素子の制御端子と第2の端子との間に設けられた第2のスイッチング素子と、前記駆動素子の第2の端子と前記第1の配線との間に設けられた第3のスイッチング素子と、前記駆動素子の制御端子と第3の配線との間に設けられたコンデンサとを含む場合に、
前記第1および第2のスイッチング素子を導通状態に、前記第3のスイッチング素子を非導通状態に制御し、前記データ線に対して、表示データに応じて変化し、かつ、前記電気光学素子への印加電圧が発光閾値電圧以下となる電位を与えるステップと、
前記第3の配線の電位を2段階に変化させるステップと、
前記第1および第2のスイッチング素子を非導通状態に、前記第3のスイッチング素子を導通状態に制御するステップとを備える。
前記画素回路が、前記駆動素子の制御端子と第4の配線との間に設けられた第4のスイッチング素子をさらに含む場合に、
前記第4の配線に前記駆動素子が導通状態となる電位を与えておき、前記第1および第2のスイッチング素子が導通状態で、前記第3のスイッチング素子が非導通状態である間に、前記第4のスイッチング素子を導通状態に制御するステップをさらに備える。
11…表示制御回路
12…ゲートドライバ回路
13…ソースドライバ回路
21…シフトレジスタ
22…レジスタ
23…ラッチ回路
24…D/A変換器
100、200、250…画素回路
110…駆動用TFT
111、112、113、214…スイッチ用TFT
121…コンデンサ
130…有機EL素子
Gi…走査線
Ri、Ui、Wi…制御配線
Sj…データ線
Vp、Vref…電源配線
Vcom…共通陰極
図2は、本発明の第1の実施形態に係る表示装置に含まれる画素回路の回路図である。図2に示す画素回路100は、駆動用TFT110、スイッチ用TFT111~113、コンデンサ121、および、有機EL素子130を備えている。画素回路100に含まれるTFTは、いずれもnチャネル型である。
Vth_oled≧Vda-VSS …(1)
Vgs=VDD-Vda …(2)
Vg=Vda+Vth+V1-V2 …(3)
Vda=Vda’-(V1-V2) …(4)
Vda≦VSS …(5)
図5は、本発明の第2の実施形態に係る表示装置に含まれる画素回路の回路図である。図5に示す画素回路200は、駆動用TFT110、スイッチ用TFT111~113、214、コンデンサ121、および、有機EL素子130を備えている。画素回路200に含まれるTFTは、いずれもnチャネル型である。本実施形態の構成要素のうち、第1の実施形態と同一の要素については、同一の参照符号を付して説明を省略する。
Vth≦Vini-(Vdaの最大値) …(6)
Claims (13)
- 電流駆動型の表示装置であって、
複数の走査線と複数のデータ線の各交差点に対応して配置された複数の画素回路と、
前記走査線を用いて、書き込み対象の画素回路を選択する走査信号出力回路と、
前記データ線に対して、表示データに応じた電位を与える表示信号出力回路とを備え、
前記画素回路は、
第1の配線と第2の配線とを結ぶ経路上に設けられ、制御端子、第1の端子および第2の端子を有し、前記経路を流れる電流を制御する駆動素子と、
前記駆動素子の第1の端子に接続して前記経路上に前記駆動素子と直列に設けられ、前記経路を流れる電流に応じた輝度で発光する電気光学素子と、
前記駆動素子の第1の端子と前記データ線との間に設けられた第1のスイッチング素子と、
前記駆動素子の制御端子と第2の端子との間に設けられた第2のスイッチング素子と、
前記駆動素子の第2の端子と前記第1の配線との間に設けられた第3のスイッチング素子と、
前記駆動素子の制御端子と第3の配線との間に設けられたコンデンサとを含み、
前記表示信号出力回路は、前記データ線に対して、前記電気光学素子への印加電圧が発光閾値電圧以下となる電位を与え、
前記走査信号出力回路は、前記第3の配線の電位を2段階に変化させることを特徴とする、表示装置。 - 前記画素回路は、前記駆動素子の制御端子と第4の配線との間に設けられた第4のスイッチング素子をさらに含む、請求項1に記載の表示装置。
- 前記第4のスイッチング素子の制御端子は、前記第4の配線に接続されていることを特徴とする、請求項2に記載の表示装置。
- 前記第4の配線には、前記駆動素子が導通状態となる電位が与えられることを特徴とする、請求項2に記載の表示装置。
- 前記画素回路に対する書き込み時には、前記第1および第2のスイッチング素子は導通状態に、前記第3のスイッチング素子は非導通状態に制御されることを特徴とする、請求項1に記載の表示装置。
- 前記走査信号出力回路は、前記第3の配線の電位の変化タイミングを調整する機能を有することを特徴とする、請求項1に記載の表示装置。
- 前記走査信号出力回路は、前記第3のスイッチング素子の制御端子に与える電位の変化タイミングを調整する機能を有することを特徴とする、請求項1に記載の表示装置。
- 前記電気光学素子は有機EL素子で構成されていることを特徴とする、請求項1に記載の表示装置。
- 電流駆動型の表示装置に複数の走査線と複数のデータ線の各交差点に対応して複数個配置される画素回路であって、
第1の配線と第2の配線とを結ぶ経路上に設けられ、制御端子、第1の端子および第2の端子を有し、前記経路を流れる電流を制御する駆動素子と、
前記駆動素子の第1の端子に接続して前記経路上に前記駆動素子と直列に設けられ、前記経路を流れる電流に応じた輝度で発光する電気光学素子と、
前記駆動素子の第1の端子と前記データ線との間に設けられた第1のスイッチング素子と、
前記駆動素子の制御端子と第2の端子との間に設けられた第2のスイッチング素子と、
前記駆動素子の第2の端子と前記第1の配線との間に設けられた第3のスイッチング素子と、
前記駆動素子の制御端子と第3の配線との間に設けられたコンデンサとを備えた、画素回路。 - 前記駆動素子の制御端子と第4の配線との間に設けられた第4のスイッチング素子をさらに備えた、請求項9に記載の画素回路。
- 前記第4のスイッチング素子の制御端子は、前記第4の配線に接続されていることを特徴とする、請求項10に記載の画素回路。
- 電流駆動型の表示装置に複数の走査線と複数のデータ線の各交差点に対応して複数個配置される画素回路の駆動方法であって、
前記画素回路が、第1の配線と第2の配線とを結ぶ経路上に設けられ、制御端子、第1の端子および第2の端子を有し、前記経路を流れる電流を制御する駆動素子と、前記駆動素子の第1の端子に接続して前記経路上に前記駆動素子と直列に設けられ、前記経路を流れる電流に応じた輝度で発光する電気光学素子と、前記駆動素子の第1の端子と前記データ線との間に設けられた第1のスイッチング素子と、前記駆動素子の制御端子と第2の端子との間に設けられた第2のスイッチング素子と、前記駆動素子の第2の端子と前記第1の配線との間に設けられた第3のスイッチング素子と、前記駆動素子の制御端子と第3の配線との間に設けられたコンデンサとを含む場合に、
前記第1および第2のスイッチング素子を導通状態に、前記第3のスイッチング素子を非導通状態に制御し、前記データ線に対して、表示データに応じて変化し、かつ、前記電気光学素子への印加電圧が発光閾値電圧以下となる電位を与えるステップと、
前記第3の配線の電位を2段階に変化させるステップと、
前記第1および第2のスイッチング素子を非導通状態に、前記第3のスイッチング素子を導通状態に制御するステップとを備えた、画素回路の駆動方法。 - 前記画素回路が、前記駆動素子の制御端子と第4の配線との間に設けられた第4のスイッチング素子をさらに含む場合に、
前記第4の配線に前記駆動素子が導通状態となる電位を与えておき、前記第1および第2のスイッチング素子が導通状態で、前記第3のスイッチング素子が非導通状態である間に、前記第4のスイッチング素子を導通状態に制御するステップをさらに備えた、請求項12に記載の画素回路の駆動方法。
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US12/937,890 US8648776B2 (en) | 2008-05-20 | 2009-02-16 | Display device, pixel circuit, and method for driving same |
JP2010512952A JP5121926B2 (ja) | 2008-05-20 | 2009-02-16 | 表示装置、画素回路およびその駆動方法 |
CN2009801134212A CN102007527B (zh) | 2008-05-20 | 2009-02-16 | 显示装置、像素电路及其驱动方法 |
BRPI0912837A BRPI0912837A2 (pt) | 2008-05-20 | 2009-02-16 | dispositivo de display, circuito de pixel, e método para acionar o mesmo |
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