JP4784050B2 - Electronic circuit, control method therefor, electro-optical device, and electronic apparatus - Google Patents

Description

  The present invention relates to an electro-optical device that drives a current-driven element such as an organic light-emitting diode element, a driving method thereof, and an electronic apparatus.

In recent years, organic light emitting diodes (Organic Light Emitting), called organic electroluminescent elements and light emitting polymer elements, are the next generation of light emitting devices that can replace liquid crystal elements.
Diodes (hereinafter referred to as “OLED elements” where appropriate) are drawing attention. Since this OLED element is a self-luminous type, it has less viewing angle dependence, and since it does not require a backlight or reflected light, it is suitable for low power consumption and thinning. It has characteristics.
Here, the OLED element is a current-type driven element that does not have voltage holdability like a liquid crystal element and cannot maintain a light emitting state when current is interrupted. Therefore, when an OLED element is driven by an active matrix method, a voltage corresponding to the gradation of the pixel is written to the gate of the driving transistor in the writing period (selection period), and the voltage is held by a gate capacitance or the like. In general, the drive transistor keeps a current corresponding to the gate voltage flowing through the OLED element.

For example, Non-Patent Document 1 discloses a general pixel circuit. This pixel circuit includes a driving transistor, a switching transistor, and a capacitor. When the switching transistor is turned on in the writing period, a voltage corresponding to the gradation to be displayed is written into the capacitor. In the light emission period, when the switching transistor is turned off and the driving transistor is turned on, the driving transistor functions as a constant current source, and a current flows through the OLED element.
“2001 FPD Technology Encyclopedia”, Electronic Journal, P.749 (Figure 2)

  However, in such a pixel circuit, there is a problem that the display quality is deteriorated because the brightness of the OLED element differs for each pixel due to variations in characteristics such as threshold voltage of the driving transistor. Since there is a certain limit in reducing the variation of the driving transistors, it has been difficult to make the entire screen uniform by the conventional method.

  SUMMARY An advantage of some aspects of the invention is that it provides an electronic circuit capable of uniform luminance, a control method thereof, an electro-optical device, and an electronic apparatus. is there.

In order to solve the above-described problems, an electronic circuit according to the present invention includes an input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, and the first power supply. An electro-optical element connected to the terminal and emitting light of a light amount corresponding to the amount of charge supplied, and a first charge holding means provided between the second power supply terminal and the first connection point to hold the charge And a second charge holding means for holding charges, provided between the first connection point and the second connection point, and provided between the input terminal and the second connection point, based on a selection signal. Input switching means for controlling the on-state and off-state, and a first switch that is provided between the first connection point and the electro-optic element and that controls the on-state and off-state based on a first control signal. Switching means.

  According to the present invention, the initialization voltage is supplied from the input terminal, the initial charge is held in the second charge holding means, and then the gradation voltage is supplied from the input terminal and the first charge holding means and the second charge holding are held. Charges can be transferred between the means. In this case, the amount of charge held in the first charge holding means after charge transfer depends on the ratio of the capacitance value of the first charge holding means and the capacitance value of the second charge holding means, and is an absolute value of the first charge holding means. Which is independent of the capacity value. For this reason, when a plurality of electronic circuits are integrated, it is possible to increase a margin for variations in luminance.

Further, in this electronic circuit, an on state and an off state are provided based on a second control signal provided between a third power supply terminal to which a third voltage is supplied and the third power supply terminal and the second connection point. It is preferable to include a second switching means for controlling the. In this case, if the initialization voltage is given as the third voltage, the gray scale voltage may be simply given as the voltage supplied to the input terminal, so that the voltage obtained by time-division multiplexing the initialization voltage and the gray scale voltage is supplied to the input terminal. There is no need to do it. For this reason, the function of the external circuit can be simplified.
Furthermore, the electronic circuit described above is provided between a fourth power supply terminal to which a fourth voltage is supplied, the fourth power supply terminal, and the first connection point, and is turned on and off based on a third control signal. And a third switching means whose state is controlled. In this case, since the fourth voltage can be supplied to the first connection point, the first control signal for controlling the first switching means can be simplified.
In addition, the electronic circuit described above preferably includes a discharging unit that discharges the electric charge accumulated in the electro-optical element. In this case, since the charge accumulated in the electro-optical element at the previous light emission can be discharged, the luminance can be accurately displayed.

Next, an electronic circuit control method according to the present invention includes an input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, and the first power supply terminal. An electro-optical element that emits light having a light amount corresponding to the amount of electric charge to be supplied; a first charge holding unit that is provided between the second power supply terminal and the first connection point; A second charge holding means provided between the first connection point and the second connection point for holding charges; an input switching means provided between the input terminal and the second connection point; A method of controlling an electronic circuit comprising a first switching means provided between a first connection point and the electro-optic element, wherein a third voltage is supplied to the input terminal during an initialization period, The input switching means and the first switching means are on. In the writing period, the gradation voltage corresponding to the gradation to be displayed is supplied to the input terminal so that the input switching means is turned on and the first switching means is turned off. And controlling so that the input switching means is turned off and the first switching means is turned on during the light emission period.

  According to the present invention, the third voltage (corresponding to the initialization voltage in the embodiment) supplied from the input terminal in the initialization period is supplied to one terminal of the second charge holding means, and the other terminal has the first voltage. A voltage obtained by adding the threshold voltage of the electro-optic element to one voltage is applied, and charges corresponding to the difference voltage are held. In the writing period, charges move between the first charge holding unit and the second charge holding unit. As a result, the amount of charge held in the first charge holding means after charge transfer depends on the capacitance value of the first charge holding means and the capacitance value of the second charge holding means, and from the capacitance value of the first charge holding means. It becomes independent. In the light emission period, the charge held in the first charge holding unit is supplied to the electro-optical element, and the electro-optical element emits light with a luminance corresponding to the amount of the charge. Since the amount of charge is determined according to the ratio of the capacitance value of the first charge holding means and the capacitance value of the second charge holding means, it is not necessary to match the capacitance value of the first charge holding means with an absolute reference. Accordingly, when displaying an image using a plurality of electronic circuits, the luminance of the plurality of electro-optical elements can be easily made uniform.

  According to another control method of the electronic circuit of the present invention, an input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, and a third voltage are supplied. Between the second power supply terminal and the first connection point, the third power supply terminal connected to the first power supply terminal, and the electro-optic element that emits light of a light amount corresponding to the supplied charge amount. A first charge holding means for holding charges; a second charge holding means for holding charges provided between the first connection point and the second connection point; and the input terminal and the second connection. An input switching means provided between the first connection point and the electro-optic element, and between the third power supply terminal and the second connection point. And a second switching means provided in the electronic control circuit. In the conversion period, the first switching means and the second switching means are controlled to be turned on, and in the writing period, a gradation voltage corresponding to a gradation to be displayed is supplied to the input terminal, The input switching means is turned on, and the first switching means and the second switching means are controlled to be turned off. During the light emission period, the first switching means is turned on, and the input switching means and the first switching means are turned on. Control is performed so that the two switching means is turned off.

  According to the present invention, the third voltage supplied to one terminal of the second charge holding means in the initialization period is supplied from the third power supply terminal instead of the input terminal. As a result, the voltage supplied from the input terminal can be set to only the gradation voltage, so that it is not necessary to supply the gradation voltage and the third voltage by time division multiplexing. As a result, it is possible to control the luminance of the electro-optic element by a simple method.

  According to another control method of the electronic circuit of the present invention, an input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, and a third voltage are supplied. A third power supply terminal, a fourth power supply terminal to which a fourth voltage is supplied, an electro-optical element connected to the first power supply terminal and emitting light of a light amount corresponding to the supplied charge amount, A first charge holding means provided between the second power supply terminal and the first connection point for holding charge; and a second charge holding means provided between the first connection point and the second connection point for holding charge. Charge holding means; input switching means provided between the input terminal and the second connection point; first switching means provided between the first connection point and the electro-optic element; A second switching means provided between a third power supply terminal and the second connection point; 4 is a control method of an electronic circuit comprising a third power supply terminal and a third switching means provided between the first connection point, wherein the first switching means is turned off during the initialization period, 2 switching means and the third switching means are controlled to be turned on, and a gradation voltage corresponding to a gradation to be displayed is supplied to the input terminal in the writing period, and the input switching means is turned on. And the first switching means, the second switching means, and the third switching means are controlled to be turned off, and the first switching means is turned on during the light emission period, and the input switching means, Control is performed so that the second switching means and the third switching means are turned off.

  According to the present invention, the fourth voltage can be supplied to the other terminal (first connection point) of the second charge holding unit by turning on the third switching unit during the initialization period. Since the voltage at the other terminal does not depend on the threshold voltage of the electro-optical element, the amount of charge held in the first charge holding unit is not affected by the threshold voltage of the electro-optical element. Accordingly, it is possible to display the luminance accurately without being affected by variations in the electro-optical element.

  Here, in the case where the electronic circuit includes a discharging unit that discharges the electric charge accumulated in the electro-optical element, the electro-optical element is partially or entirely in a period other than the period in which the first switching unit is turned on. It is preferable to control the discharge means so as to discharge the electric charge accumulated in the battery. In this case, it is possible to forcibly discharge the charge supplied to the electro-optical element in the previous light emission period, and thus it is possible to display accurate luminance.

Next, an electro-optical device according to the present invention includes a plurality of pixel circuits and a driving unit that drives each of the plurality of pixel circuits, and each of the plurality of pixel circuits includes an input terminal, a first voltage, and the like. A first power supply terminal to which is supplied, a second power supply terminal to which a second voltage is supplied, an electro-optical element connected to the first power supply terminal and emitting light of a light amount corresponding to the supplied charge amount , Provided between the second power supply terminal and the first connection point, and provided between the first connection point and the second connection point, the first charge holding means for holding the charge, and holds the charge. A second charge holding unit; an input switching unit which is provided between the input terminal and the second connection point and whose on state and off state are controlled based on a selection signal; the first connection point and the electric point Provided between the optical element and on-state and off-state based on the first control signal And a first switching means for controlling the input switching means, wherein the driving means supplies a third voltage to the input terminal during an initialization period and outputs the selection signal for turning on the input switching means. The first control signal for turning on the first switching means is supplied to the first switching means, and a gradation voltage corresponding to the gradation to be displayed is supplied to the input terminal during the writing period. And supplying the selection signal for turning on the input switching means to the input switching means, supplying the first control signal for turning off the first switching means to the first switching means, and emitting light. Supplying the selection signal for turning off the input switching means to the input switching means in a period; It said first control signal to the switching means to the ON state and supplying to said first switching means.

  According to the present invention, the charge held in the second charge holding means in the initialization period is moved between the first charge holding means and the second charge holding means in the writing period. For this reason, the amount of charge held in the first charge holding means after charge transfer is determined by the relative relationship between the capacitance value of the first charge holding means and the capacitance value of the second charge holding means. Therefore, in order to make the luminance of the entire screen uniform, it is not necessary to match the capacitance value of the first charge holding means with the absolute reference, and the ratio between the capacitance value of the first charge holding means and the capacitance value of the second charge holding means. May be manufactured so that is constant. As a result, a large margin for variations in the manufacturing process can be obtained.

  In addition, another electro-optical device according to the present invention includes a plurality of pixel circuits and a driving unit that drives each of the plurality of pixel circuits, and each of the plurality of pixel circuits includes an input terminal, a first terminal, A first power supply terminal to which a voltage is supplied, a second power supply terminal to which a second voltage is supplied, a third power supply terminal to which a third voltage is supplied, and a charge supplied to the first power supply terminal An electro-optical element that emits light of an amount corresponding to the amount; a first charge holding unit that is provided between the second power supply terminal and the first connection point; and holds charge; the first connection point and the first connection point; A second charge holding means provided between two connection points and holding a charge; and provided between the input terminal and the second connection point, and an on state and an off state are controlled based on a selection signal. Input switching means, and provided between the first connection point and the electro-optic element. A first switching means for controlling an on-state and an off-state based on a first control signal; and provided between the third power supply terminal and the second connection point; and an on-state based on a second control signal Second switching means for controlling the OFF state, and the driving means controls the first switching means and the second switching means to be in the ON state in the initialization period, and in the writing period, A gradation voltage corresponding to a gradation to be displayed is supplied to the input terminal, the input switching means is turned on, and the first switching means and the second switching means are controlled to be turned off, and light emission During the period, the first switching means is turned on, and the input switching means and the second switching means are turned off. To, characterized in that.

  According to the present invention, since the third voltage can be supplied to the second connection point via the second switching means, the driving means needs to supply different voltages to the input terminal in the initialization period and the writing period. There is no. Therefore, the driving unit only needs to output the gradation voltage without switching the third voltage and the gradation voltage, and the configuration can be simplified.

  In addition, another electro-optical device according to the present invention includes a plurality of pixel circuits and a driving unit that drives each of the plurality of pixel circuits, and each of the plurality of pixel circuits includes an input terminal, a first terminal, A first power supply terminal to which a voltage is supplied; a second power supply terminal to which a second voltage is supplied; a third power supply terminal to which a third voltage is supplied; a fourth power supply terminal to which a fourth voltage is supplied; An electro-optical element that is connected to the first power supply terminal and emits light of a light amount corresponding to the supplied charge amount, and is provided between the second power supply terminal and the first connection point, and holds a charge. 1 charge holding means, provided between the first connection point and the second connection point, provided between the second charge holding means for holding charge, the input terminal and the second connection point, Input switching means for controlling an on state and an off state based on a selection signal; and the first connection Provided between the first power supply terminal and the second connection point. The first switching means is provided between the first power supply terminal and the second connection point. Provided between the second switching means whose on-state and off-state are controlled based on the second control signal, the fourth power supply terminal and the first connection point, and is turned on based on the third control signal. And a third switching means for controlling the state and the off-state, and the driving means supplies the first switching signal to the first switching means for turning off the first switching means during the initialization period. The second control signal for turning on the second switching means is supplied to the second switching means, and the third control signal for turning on the third switching means is supplied to the third switching signal. Is supplied to the switching means, and in the writing period, a gradation voltage corresponding to the gradation to be displayed is supplied to the input terminal, and the selection signal for turning on the input switching means is supplied to the input switching means. Supplying the first control signal for turning off the first switching means to the first switching means, and supplying the second control signal for turning off the second switching means to the second switching means. Supplying the third control signal for turning off the third switching means to the third switching means, and turning on the first control signal for turning on the first switching means during the light emission period. And the selection signal for turning off the input switching means is supplied to the input switching means. The second control signal for turning off the second switching means is supplied to the second switching means, and the third control signal for turning off the third switching means is supplied to the third switching means. It is characterized by that.

  According to the present invention, since the fourth voltage is supplied to the first connection point via the third switching means during the initialization period, the voltage applied to the second charge holding means is the threshold voltage of the electro-optic element. Can be irrelevant. Therefore, even if the threshold voltage of each electro-optical element varies, the luminance of the entire screen can be kept uniform.

  In the electro-optical device described above, it is preferable that the driving unit supplies the second control signal to the third switching unit instead of the third control signal. In this case, since the second control signal (first initialization signal in the embodiment) also serves as the third control signal (second initialization signal in the embodiment), the configuration of the driving means can be simplified and individual signals can be obtained. The wiring structure can be simplified as compared with the case where the wiring is routed.

  In the electro-optical device described above, each of the plurality of pixel circuits includes a discharging unit that discharges electric charges accumulated in the electro-optical element, and the driving unit turns on the first switching unit. It is preferable to control the discharging means so as to discharge the charge accumulated in the electro-optic element in part or all of the period other than the period. In this case, since the electric charge accumulated in the electro-optical element is forcibly discharged during the previous light emission period, the luminance can be accurately displayed.

  Further, in the above-described electro-optical device, each of the plurality of pixel circuits includes a discharge switching unit that is connected in parallel with the electro-optical element and that controls an on state and an off state based on a discharge control signal. The driving means preferably supplies the selection signal as the discharge control signal to the discharge switching means. In this case, since the discharge control signal can be used also as the selection signal, the configuration of the driving means can be simplified, and in addition, the wiring structure can be simplified.

  The electro-optical device described above preferably supplies the first voltage to the second power supply terminal. Furthermore, the electro-optical device described above may supply either the first voltage or the second voltage to the third power supply terminal. In addition, the above-described electro-optical device may supply either the first voltage, the second voltage, or the third voltage to the fourth power supply terminal.

  Next, an electronic apparatus according to the present invention includes the above-described electro-optical device, and includes, for example, a personal computer, a mobile phone, a portable information terminal, a monitor, a digital still camera, a viewfinder, and the like.

<1. First Embodiment>
FIG. 1 is a block diagram showing a schematic configuration of an electro-optical device 1 according to the first embodiment of the present invention. The electro-optical device 1 includes a pixel region A, a scanning line driving circuit 100, a data line driving circuit 200, a control circuit 300, and a power supply circuit 500. Among these, in the pixel region A, m scanning lines 101 and m light emission control lines 102 are formed in parallel with the X direction. In addition, n data lines 110 are formed in parallel with the Y direction orthogonal to the X direction. A pixel circuit 400 </ b> A is provided corresponding to each intersection of the scanning line 101 and the data line 110. Pixel circuit 400A includes an OLED element.

The scanning line driving circuit 100 generates scanning signals (selection signals) Y1, Y2, Y3,..., Ym for sequentially selecting a plurality of scanning lines 101 and emits light control signals Vg-1, Vg-2, Vg-. 3, ... Vg-m is generated. The scanning signals Y1 to Ym and the light emission control signals Vg-1 to Vg-m are generated by sequentially transferring the Y transfer start pulse DY in synchronization with the Y clock signal YCLK. The light emission control signals Vg-1, Vg-2, Vg-3,..., Vg-m are supplied to the pixel circuits 400A via the light emission control lines 102, respectively.
The data line driving circuit 200 positions the data signals X1 to Xn generated based on the output gradation data Dout in a row selected by the scanning line driving circuit 100 via the data lines 110 in the 1st to nth columns. This is supplied to each of the pixel circuits 400A in 1 to n columns. The data signals X1 to Xn in the first embodiment are gradation voltages corresponding to the current (that is, the gradation of the pixel) to be passed through the OLED element of the pixel circuit 400A.
For convenience of explanation, a data signal supplied to the data line 110 in the j-th column (j is an integer satisfying 1 ≦ j ≦ n and used for generalizing the column) is denoted as Xj. . A scanning signal supplied to the scanning line 101 in the i-th row (i is an integer satisfying 1 ≦ i ≦ m) is denoted as Yi.

The control circuit 300 generates various control signals such as a Y clock signal YCLK, an X clock signal XCLK, an X transfer start pulse DX, and a Y transfer start pulse DY, and sends them to the scanning line drive circuit 100 and the data line drive circuit 200. Output. In addition, the control circuit 300 performs signal processing such as DA conversion and gamma correction on the externally supplied digital gradation data Din to generate output gradation data Dout.
The power supply circuit 500 supplies the low potential side voltage VL (first voltage) and the charge holding reference voltage VC (second voltage) to each pixel circuit 400A. It is preferable that VL ≦ VC.

  Next, the pixel circuit 400A will be described. FIG. 2 shows a circuit diagram of the pixel circuit 400A located in i row and j column. The pixel circuit 400A includes two TFTs 401 and 402, a first capacitor element 410, and an OLED element 420. In the manufacturing process of the TFTs 401 and 402, a polysilicon layer is formed on the glass substrate using laser annealing shot. In the OLED element 420, a light emitting layer is sandwiched between an anode and a cathode. The OLED element 420 emits light with a luminance corresponding to the forward current. An organic EL (Electronic Luminescence) material corresponding to the emission color is used for the light emitting layer. In the manufacturing process of the light emitting layer, for example, an organic EL material is ejected as droplets from an inkjet head and dried.

  The source electrode of the TFT 401 is connected to the data line 110. On the other hand, the drain electrode is connected to the first connection point Z1. The drain electrode of the TFT 402 is connected to the first connection point Z 1, and its source electrode is connected to the anode of the OLED element 420. The gate electrode of the TFT 401 is connected to the scanning line 101, and a scanning signal Yi is supplied. On the other hand, the gate electrode of the TFT 402 is connected to the light emission control line 102 and supplied with the light emission control signal Vg-i. The TFTs 401 and 402 function as switching means for performing an on / off operation. In the present invention, the TFT 401 corresponds to input switching means and the TFT 402 corresponds to first switching means.

  A connection point between the source electrode of the TFT 401 and the data line 110 functions as an input terminal for taking in the data signal Xj into the pixel circuit 400A. The cathode of the OLED element 420 is connected to a first power supply line (not shown), and the low potential side voltage VL is supplied through the first power supply line. The connection point between the cathode and the first power supply line functions as a first power supply terminal that takes in the low potential side voltage VL. Furthermore, one terminal of the first capacitive element 410 is connected to a second power supply line (not shown), and the other terminal is connected to the first connection point Z1. The charge holding reference voltage VC is supplied to the first capacitor element 410 via the second power supply line. A connection point between the first capacitive element 410 and the second power supply line functions as a second power supply terminal that takes in the charge retention reference voltage VC.

FIG. 3 shows an example of a timing chart of the pixel circuit 400A. 4 and 5 show an equivalent circuit of the pixel circuit 400A. Operation of the pixel circuit 400A of the present embodiment is broadly divided into the light-emitting period _{T EL} and writing time _{T WRT.}
The scanning signal Y1 is a pulse having a width substantially corresponding to one horizontal scanning period (1H) from the first timing of one vertical scanning period (1V), and is supplied to the first scanning line 101. Thereafter, the pulses are sequentially shifted, and the scanning signals Y2, Y3,..., Ym are supplied to the scanning lines 101 in the 2, 3,. When the scanning signal Yi in the i-th row becomes H level, the scanning line 101 is selected.

In the pixel circuit 400A in the i-th row and j-th column, when the scanning signal Yi becomes H level, the TFT 401 is turned on, and the data signal Xj is supplied to the first capacitor element 410. In the following description, the gradation voltage of the data signal Xj is Vdata, and the capacitance value of the first capacitor element 410 is C1. In the writing period _TWRT , as shown in FIG. 4, the TFT 401 is turned on and the TFT 402 is turned off, and a voltage (Vdata−VC) is applied to the first capacitor element 410. Therefore, the retained charge amount Q1 stored in the first capacitor element 410 is given by the following equation (1).
Q1 = (Vdata−VC) × C1 (1)

Next, the light-emitting period _{T EL,} as shown in FIG. 5, TFT 401 is turned off, it TFT402 is turned on, charge Q held in the first capacitor element 410 flows through the OLED element 420. The light quantity of the OLED element 420 is determined by the product of the current Ioled flowing through the OLED element 420 and time t. Therefore, the luminance of the OLED element 420 is proportional to the retained charge amount Q1.

  According to this driving method, the charge supplied to the OLED element 420 per unit time (in this example, one vertical scanning period) is written to the first capacitor element 410, and the written charge is supplied to the OLED element 420. . Since the luminance of the OLED element 420 depends on the charge amount Q1, it is determined only by the voltage Vdata, the low potential side voltage VL, the charge holding reference voltage VC, and the capacitance value C1. That is, since the TFT 401 and the TFT 402 merely function as switching means, even if their electrical characteristics vary, the luminance of the OLED element 420 is not affected. Therefore, it is possible to display the entire screen with uniform brightness. In FIG. 2, the TFT 402 is an N-type TFT, but this may be a P-type TFT, and the gate control of the TFT 402 may be performed by the scanning signal Yi. In this case, the light emission control signal Vg-i is not necessary, and the configuration can be simplified. Further, the low potential side voltage VL may be used instead of the charge holding reference voltage VC. In that case, since it is not necessary to supply a special power source as a VC, the configuration can be simplified.

<2. Second Embodiment>
The electro-optical device 10 of the second embodiment is configured in the same manner as in the first embodiment, except that a pixel circuit 400B is used instead of the pixel circuit 400A.
FIG. 6 shows a circuit diagram of the pixel circuit 400B located in i row and j column. In the pixel circuit 400 </ b> B, a TFT 403 is provided in parallel with the OLED element 420. The drain electrode of the TFT 403 is connected to the anode of the OLED element 420, and the source electrode is connected to the cathode of the OLED element 420. Further, the gate electrode of the TFT 403 is connected to the discharge control line 103, and a discharge control signal Vdis-i is supplied from the scanning line driving circuit 100 via the discharge control line 103. The TFT 403 functions as a discharge unit that discharges the charge accumulated in the OLED element 420.

  FIG. 7 shows an example of a timing chart of the pixel circuit 400B. 8 to 10 show equivalent circuits of the pixel circuit 400B. First, in the period from time t1 to time t2, since the scanning signal Yi is at the H level and the light emission control signal Vg-i and the discharge control signal Vdis-i are at the L level, the TFT 401 is turned on, and the TFTs 402 and 403 are turned on. Turns off. As a result, the voltage Vdata is supplied to the first capacitor element 410 as shown in FIG.

Next, in the discharge period Tdis from time t2 to time t3, the discharge control signal Vdis-i becomes H level, so that the TFT 403 is turned on. As a result, as shown in FIG. 9, the anode and cathode of the OLED element 420 are short-circuited, and the charge accumulated in the OLED element 420 is discharged. At this time, since the TFT 402 is in an off state, charge is written to the first capacitor element 410 at the same time. Further, in the period from time t3 to time t4, charge is written in the same manner as from time t1 to time t2. In the light emission period TEL, as shown in FIG. 10, the _TFTs 401 and 403 are turned off, and the TFT 402 is turned on to supply charges to the OLED element 420.

According to this embodiment, since the discharging charges accumulated in the OLED device 420, the state of the OLED element 420 in the previous emission period T _EL, can be such that the display luminance in this emission period T _EL is not affected. As a result, it is possible to display accurate luminance, and display quality can be improved.
Note that the scanning signal Yi may be used instead of the discharge control signal Vdis-i. In this case, since it is not necessary to individually generate the discharge control signal Vdis-i, the configuration of the scan driving circuit 100 can be simplified, and the wiring structure can be simplified by omitting the discharge control line 103.

<3. Third Embodiment>
The electro-optical device 10 of the third embodiment is configured in the same manner as in the first embodiment, except that a pixel circuit 400C is used instead of the pixel circuit 400A.
FIG. 11 shows a circuit diagram of a pixel circuit 400C located in i row and j column. The pixel circuit 400C includes a second capacitor element 411 between the TFT 401 and the first connection point Z1. In the following description, a connection point between the TFT 401 and the second capacitor element 411 is referred to as a second connection point Z2.
FIG. 12 shows an example of a timing chart of the pixel circuit 400C. 13 to 15 show equivalent circuits of the pixel circuit 400C. Operation of the pixel circuit 400C of the present embodiment is broadly divided initialization period _{T init,} the writing time _{T WRT} and the light-emitting period _{T EL.}

In the present embodiment, the data line driving circuit 200, initializing voltage Vinit next in the initialization period _{T init,} and generates a data signal Xj as a gradation voltage Vdata in the writing period _{T WRT.} In the initialization period _Tinit , since the scanning signal Yi and the light emission control signal Vg-i are at the H level, the TFTs 401 and 402 are turned on. As a result, as shown in FIG. 13, the voltage at the second connection point Z2 becomes the initialization voltage Vinit. Here, if the threshold voltage of the OLED element 420 is Vtoled, the voltage at the first connection point Z1 is VL + Vtoled. Therefore, the voltage applied to the second capacitor element 411 is Vinit− (VL + Vtoled).

Next, in the writing period _TWRT , the light emission control signal Vg-i is at the L level, so that the TFT 402 is turned off. Further, the gradation voltage Vdata is supplied as the data signal Xj.
As a result, charges move between the first capacitor element 410 and the second capacitor element 411 as shown in FIG. If the retained charge amount of the first capacitor element 410 in this state is Q2, and the capacitance value of the second capacitor element 411 is C2, the retained charge amount Q2 is given by the following equation (2).
Q2 = [(Vdata−Vinit) {C2 / (C1 + C2)} + VL + Vtoled−VC] × C1 (2)

In the light emission period _TEL , since the scanning signal Yi is at the L level and the light emission control signal Vg-i is at the H level, the TFT 401 is turned off and the TFT 402 is turned on. As a result, charges are supplied from the first capacitor element 410 to the OLED element 420 as shown in FIG. At this time, the retained charge amount Q2 is supplied to the OLED element 420.

  The luminance of the OLED element 420 is proportional to the retained charge amount Q2, but the retained charge amount Q2 is given by the ratio between the capacitance value C1 and the capacitance value C2 from the equation (2). This is important in that the entire screen is displayed uniformly. That is, in the first embodiment, since the retained charge amount Q1 depends on the capacitance value C1, it is necessary to match the capacitance value C1 of the first capacitance element 410 with the absolute reference in the entire screen in order to obtain a uniform display. there were. On the other hand, in this embodiment, it is sufficient to keep the relative relationship between the capacitance value C1 and the capacitance value C2 constant, so that it is possible to greatly increase the margin for variations in the manufacturing process.

<4. Fourth Embodiment>
The electro-optical device 10 of the fourth embodiment is configured in the same manner as in the third embodiment except that a pixel circuit 400D is used instead of the pixel circuit 400C.
FIG. 16 shows a circuit diagram of a pixel circuit 400D located in i row and j column. In the pixel circuit 400 </ b> D, a TFT 403 is provided in parallel with the OLED element 420. The drain electrode of the TFT 403 is connected to the anode of the OLED element 420, and the source electrode is connected to the cathode of the OLED element 420. Further, the gate electrode of the TFT 403 is connected to the discharge control line 103, and a discharge control signal Vdis-i is supplied from the scanning line driving circuit 100 via the discharge control line 103. The TFT 403 functions as a discharge unit that discharges the charge accumulated in the OLED element 420.

FIG. 17 shows an example of a timing chart of the pixel circuit 400D. 18 to 20 show equivalent circuits of the pixel circuit 400D. First, in the initialization period _{T init,} the scanning signal Yi and the emission control signal Vg-i is H level, the discharge control signal Vdis-i is because it is L level, TFT 401 and TFT402 is turned on, TFT 403 is turned off It becomes. As a result, the voltage Vinit− (VL + Vtoled) is applied to the second capacitor element 411 as shown in FIG.

Next, in the writing period T _WRT, while the emission control signal Vg-i becomes the L level, the discharge control signal Vdis-i since the H level, the first capacitive element 410 and the second capacitive element 411 The electric charge moves between them, and the TFT 403 is turned on. As a result, as shown in FIG. 19, the anode and cathode of the OLED element 420 are short-circuited, and the charge accumulated in the OLED element 420 is discharged. At this time, since the TFT 402 is in an off state, the movement of charges is performed only between the first capacitor element 410 and the second capacitor element 411. In the light emission period TEL, as shown in FIG. 20, the _TFTs 401 and 403 are turned off, while the TFT 402 is turned on, and the above-described charge Q2 is supplied to the OLED element 420.
Q2 = [(Vdata−Vinit) {C2 / (C1 + C2)} + VL + Vtoled−VC] × C1 (2)

According to this embodiment, since the discharging charges accumulated in the OLED device 420, the state of the OLED element 420 in the previous emission period T _EL, can be such that the display luminance in this emission period T _EL is not affected. As a result, it is possible to display accurate luminance, and display quality can be improved.

  Note that the scanning signal Yi may be used instead of the discharge control signal Vdis-i. In this case, since it is not necessary to generate the discharge control signal Vdis-i by the scanning line driving circuit 100, the configuration of the scanning line driving circuit 100 can be simplified, and the discharge control line 103 is omitted. Therefore, the wiring structure can be simplified.

Incidentally, when the initialization period _{T init} and the discharge period Tdis exclusively provided is the applied voltage of the second capacitive element 411 as shown in FIG. 18 becomes Vinit- (VL + Vtoled). However, the use of the scanning signal Yi in place of the discharge control signal Vdis-i, so that the initialization period T _init and the discharge period Tdis overlap. In this case, the pixel circuit 400D can be represented by an equivalent circuit shown in FIG. Since the voltage of the first connection point Z1 in the setup period _{T init} As apparent from the figure at the low-potential-side voltage VL, the voltage applied to the second capacitive element 411 becomes (Vinit-VL). That is, by overlapping the initialization period T _init and the discharge period Tdis, it is possible to remove the term of the threshold voltage Vtoled. As a result, if the retained charge amount retained in the first capacitor element 410 after the charge transfer in the writing period _TWRT is Q3, the retained charge amount Q3 is given by the following equation (3).
Q3 = [(Vdata−Vinit) {C2 / (C1 + C2)} + VL−VC] × C1 (3)
Although the luminance of the OLED element 420 is proportional to the held charge amount Q3, as is clear from the equation (3), it does not depend on the threshold voltage Vtoled. Accordingly, even if the threshold voltage Vtoled of the OLED element 420 varies over the entire screen, uniform luminance can be displayed.

<5. Fifth Embodiment>
The electro-optical device 10 of the fifth embodiment is configured in the same manner as in the third embodiment except that a pixel circuit 400E is used instead of the pixel circuit 400C.
FIG. 22 shows a circuit diagram of the pixel circuit 400E located in i row and j column. The pixel circuit 400E includes a TFT 404. The drain electrode of the TFT 404 is connected to the second connection point Z2, and its source electrode is connected to a third power supply line (not shown). An initialization voltage Vinit (third voltage) is supplied through the third power supply line. The connection point between the TFT 404 and the third power supply line functions as a third power supply terminal that takes in the initialization voltage Vinit. The gate electrode of the TFT 404 is connected to the first initialization control line 104, and the initialization signal Gini 1 -i is supplied from the scanning line driving circuit 100 through the first initialization control line 104. Initialization signal GINI1-i is a signal which becomes active (H level) in the initialization period T _init.

FIG. 23 shows an example of a timing chart of the pixel circuit 400E. 24 to 26 show equivalent circuits of the pixel circuit 400E. Operation of the pixel circuit 400E according to the present embodiment, the initialization period _{T init,} is divided into a writing period _{T WRT} and the light-emitting period _{T EL,} this point is the same as the third embodiment. In the initialization period _{T init,} the emission control signal Vg-i and the initialization signal GINI1-i becomes the H level, TFT 402 and TFT404 is turned on. As a result, as shown in FIG. 24, the voltage at the second connection point Z2 becomes the initialization voltage Vinit, while the voltage at the first connection point Z1 becomes VL + Vtoled. Accordingly, the voltage applied to the second capacitive element 411 is Vinit− (VL + Vtoled) as in the third embodiment.

Next, in the writing period _{T WRT,} the emission control signal Vg-i and the initialization signal GINI1-i becomes the L level, TFT 402 and TFT404 are turned off. Further, the gradation voltage Vdata is supplied from the data line driving circuit 200 as the data signal Xj. As a result, charges move between the first capacitor element 410 and the second capacitor element 411 as shown in FIG. The retained charge amount of the first capacitor element 410 in this state is Q2 given by the equation (2) described in the third embodiment. Then, the light-emitting period _{T EL,} the scanning signal Yi and the initialization signal GINI1-i is L level, the emission control signal Vg-i becomes the H level, TFT 401 and TFT404 is turned off, TFT 402 is turned on. As a result, charges are supplied from the first capacitor element 410 to the OLED element 420 as shown in FIG. At this time, since the retained charge amount Q2 is supplied to the OLED element 420, the OLED element 420 emits light with a luminance corresponding to the retained charge amount Q2.

  In this embodiment, since the initialization voltage Vinit is supplied via the TFT 404, it is not necessary to supply the initialization voltage Vinit from the data line driving circuit 200. In the third embodiment, since the initialization voltage Vinit and the gradation voltage Vdata are time-division multiplexed on the data signal Xj, the data line driving circuit 200 needs to have a function of switching these voltages. On the other hand, in the present embodiment, the configuration of the data line driving circuit 200 can be simplified.

Note that the light emission control signal Vg-i may be used instead of the initialization signal Gini1-i. In this case, the scanning signal Yi may be used instead of the discharge control signal Vdis-i. In this case, since it is not necessary to individually generate the initialization signal Gini1-i, the configuration of the scan driving circuit 100 can be simplified, and the wiring structure can be simplified by omitting the first initialization control line 104.
Further, a period in which the initialization signal Gini1-i and the light emission control signal Vg-i are at the H level may be set before the horizontal scanning period (1H) in which the pixel circuit 400E is selected. Thereby, the time of the writing period _TWRT can be increased. Further, the low potential side voltage VL or the charge holding reference voltage VC may be used instead of the initialization voltage Vinit. In that case, it is not necessary to supply a special power source as Vinit, so that the configuration can be simplified.

<6. Sixth Embodiment>
The electro-optical device 10 of the sixth embodiment is configured in the same manner as in the fifth embodiment except that a pixel circuit 400F is used instead of the pixel circuit 400E.
FIG. 27 shows a circuit diagram of a pixel circuit 400F located in i row and j column. In the pixel circuit 400F, a TFT 403 is provided in parallel with the OLED element 420.
FIG. 28 shows an example of a timing chart of the pixel circuit 400F. 29 to 31 show an equivalent circuit of the pixel circuit 400F. First, in the initialization period _{T init,} since the emission control signal Vg-i and the initialization signal GINI1-i becomes the H level, the scanning signal Yi and the discharge control signal Vdis-i becomes the L level, TFT 402 and TFT404 ON The TFT 401 and the TFT 403 are turned off. As a result, as shown in FIG. 29, the voltage Vinit− (VL + Vtoled) is applied to the second capacitor element 411.

Next, in the writing period T _WRT, while the emission control signal Vg-i and the initialization signal GINI1-i becomes the L level, since the scanning signal Yi and the discharge control signal Vdis-i becomes the H level, the first The charge moves between the capacitor 410 and the second capacitor 411, and the TFT 403 is turned on. As a result, as shown in FIG. 30, the anode and cathode of the OLED element 420 are short-circuited, and the charge accumulated in the OLED element 420 is discharged. Then, in the light emitting period _{T EL,} TFT401,403 as shown in FIG. 31, and 404 while the OFF state, TFT 402 is turned on, electric charges Q2 described above to the OLED element 420 is supplied.
According to this embodiment, as in the second and fourth embodiments, since the discharging charges accumulated in the OLED device 420, the state of the OLED element 420 in the previous emission period T _EL, the current emission time period T The display brightness in _EL can be prevented from being affected. As a result, it is possible to display accurate luminance, and display quality can be improved.

  Note that the scanning signal Yi may be used instead of the discharge control signal Vdis-i. In this case, since it is not necessary to generate the discharge control signal Vdis-i by the scanning line driving circuit 100, the configuration of the scanning line driving circuit 100 can be simplified, and the discharge control line 103 is omitted. Therefore, the wiring structure can be simplified.

The initial period T _init and the discharge period Tdis may be set so as to overlap. In this case, the pixel circuit 400F can be represented by an equivalent circuit shown in FIG. Since the voltage of the first connection point Z1 in the setup period _{T init} As apparent from the figure at the low-potential-side voltage VL, the voltage applied to the second capacitive element 411 becomes (Vinit-VL). That is, by overlapping the initialization period T _init and the discharge period Tdis, it is possible to remove the term of the threshold voltage Vtoled. As a result, if the retained charge amount retained in the first capacitor element 410 after the charge transfer in the writing period _TWRT is Q3, the retained charge amount Q3 is given by the following equation (3).
Q3 = [(Vdata−Vinit) {C2 / (C1 + C2)} + VL−VC] × C1 (3)
Although the luminance of the OLED element 420 is proportional to the held charge amount Q3, as is clear from the equation (3), it does not depend on the threshold voltage Vtoled. Accordingly, even if the threshold voltage Vtoled of the OLED element 420 varies over the entire screen, uniform luminance can be displayed.

<7. Seventh Embodiment>
The electro-optical device 10 according to the seventh embodiment is configured in the same manner as in the fifth embodiment except that a pixel circuit 400G is used instead of the pixel circuit 400E.
FIG. 33 shows a circuit diagram of a pixel circuit 400G located in i row and j column. The pixel circuit 400G includes a TFT 405. The source electrode of the TFT 405 is connected to the first connection point Z1, and its drain electrode is connected to a fourth power supply line (not shown). The second low potential side voltage VR (fourth voltage) is supplied through the fourth power supply line. A connection point between the TFT 405 and the fourth power supply line functions as a fourth power supply terminal that takes in the second low potential side voltage VR. The gate electrode of the TFT 405 is connected to the second initialization control line 105, and the second initialization signal Gini2-i is supplied from the scanning line driving circuit 100 through the second initialization control line 105. Second initialization signal GINI2-i is a signal which becomes active (H level) in the initialization period T _init. In the following description, the low potential side voltage VL supplied via the first power supply terminal is referred to as the first low potential side voltage VL in order to distinguish it from the second low potential side voltage VR. Further, the initialization signal Gini1-i supplied to the TFT 404 is referred to as a first initialization signal Gini1-i to distinguish it from the second initialization signal Gini2-i.

FIG. 34 shows an example of a timing chart of the pixel circuit 400G. 35 to 37 show equivalent circuits of the pixel circuit 400G. Operation of the pixel circuit 400G of the present embodiment, the initialization period _{T init,} is divided into a writing period _{T WRT} and the light-emitting period _{T EL,} this point is the same as the fifth embodiment. In the initialization period _{T init,} since the first initialization signal GINI1-i and the second initialization signal GINI2-i becomes the H level, TFT 404 and TFT405 turns on. On the other hand, since the scanning signal Yi and the light emission control signal Vg-i are at the L level, the TFT 401 and the TFT 402 are turned off. As a result, as shown in FIG. 35, the voltage at the second connection point Z2 becomes the initialization voltage Vinit, while the voltage at the first connection point Z1 becomes VR. Accordingly, the voltage applied to the second capacitor element 411 is Vinit−VR.

Then, in the writing period _{T WRT,} the emission control signal Vg-i, since the first initialization signal GINI1-i and the second initialization signal GINI2-i becomes the L level, TFT 402, TFT 404 and TFT405 and the OFF state Become. At this time, the scanning signal Yi becomes H level, the TFT 401 is turned on, and the gradation voltage Vdata is supplied from the data line driving circuit 200 as the data signal Xj. As a result, charges move between the first capacitor element 410 and the second capacitor element 411 as shown in FIG. If the retained charge amount retained in the first capacitive element 410 after the charge movement in the writing period _TWRT is Q4, the retained charge amount Q4 is given by the following equation (4).
Q4 = [(Vdata−Vinit) {C2 / (C1 + C2)} + VR−VC] × C1 (4)

Then, the light-emitting period _{T EL,} the scanning signal Yi, the first initialization signal GINI1-i and the second initialization signal GINI2-i is L level, the emission control signal Vg-i becomes the H level, TFT 401, TFT 404, and The TFT 405 is turned off and the TFT 402 is turned on. As a result, charges are supplied from the first capacitor element 410 to the OLED element 420 as shown in FIG. At this time, since the retained charge amount Q4 is supplied to the OLED element 420, the OLED element 420 emits light with a luminance corresponding to the retained charge amount Q4. The retained charge amount Q4 does not include the term of the threshold voltage Vtoled of the OLED element 420 as shown in Expression (4). Accordingly, even if the threshold voltage Vtoled of the OLED element 420 varies over the entire screen, uniform luminance can be displayed.

In the fifth embodiment, since it is necessary to TFT402 the on state in the initialization period _{T init,} the emission control signal Vg-i had become in the initialization period _{T init} and writing time _{T WRT} to H level. For this reason, the scanning line driving circuit 100 has to generate the light emission control signal Vg-i so as to be active at two timings, and the configuration is complicated. In contrast, in the present embodiment, since the adding TFT 405, the emission control signal Vg-i becomes active only in the writing period T _WRT. Therefore, according to the present embodiment, the scanning line driving circuit 100 can be easily configured.

In the above-described embodiment, the first initialization signal Gini1-i and the second initialization signal Gini2-i are individually supplied, but the first initialization signal Gini1 is used instead of the second initialization signal Gini2-i. -i may be supplied. In this case, the configuration of the scanning line driving circuit 100 can be further simplified. Further, since the second initialization control line 105 can be omitted, the wiring structure can be simplified.
Further, the TFT 405 may be provided between the first connection point Z1 and the cathode of the OLED element 420. In this case, since it is not necessary to supply the second low potential side voltage VR, the fourth power supply line can be omitted.
In addition, by setting the initialization period T _init to the first initialization signal GINI1-i and the second initialization signal GINI2-i becomes the H level before the horizontal scanning period in which the pixel circuit 400G is selected (1H) May be. As a result, it is possible to ensure a long writing period _TWRT . Further, the low potential side voltage VL or the charge holding reference voltage VC may be used instead of the second low potential side voltage VR. In that case, since it is not necessary to supply a special power supply as VR, the configuration can be simplified.

<8. Eighth Embodiment>
The electro-optical device 10 according to the eighth embodiment is configured in the same manner as in the seventh embodiment except that a pixel circuit 400H is used instead of the pixel circuit 400G.
FIG. 38 shows a circuit diagram of the pixel circuit 400H located in i row and j column. In the pixel circuit 400H, a TFT 403 is provided in parallel with the OLED element 420. The drain electrode of the TFT 403 is connected to the anode of the OLED element 420, and the source electrode is connected to the cathode of the OLED element 420. Further, the gate electrode of the TFT 403 is connected to the discharge control line 103, and a discharge control signal Vdis-i is supplied from the scanning line driving circuit 100 via the discharge control line 103. The TFT 403 functions as a discharge unit that discharges the charge accumulated in the OLED element 420.

FIG. 39 shows an example of a timing chart of the pixel circuit 400H. 40 to 42 show equivalent circuits of the pixel circuit 400H. First, in the initialization period T _init, while the first initialization signal GINI1-i and the second initialization signal GINI2-i as in the seventh embodiment becomes H level, the scanning signal Yi, the emission control signal Vg- i and the discharge control signal Vdis-i become L level. As a result, as shown in FIG. 40, the TFT 404 and the TFT 405 are turned on, and the TFTs 401 to 403 are turned off. A voltage (Vinit−VR) is applied to the second capacitor element 411.

Next, in the writing period T _WRT, the emission control signal Vg-i, while the first initialization signal GINI1-i and the second initialization signal GINI2-i becomes the L level, the scanning signal Yi and the discharge control signal Vdis -i becomes H level. As a result, as shown in FIG. 41, charges move between the first capacitor element 410 and the second capacitor element 411, and the TFT 403 is turned on. At this time, the anode and cathode of the OLED element 420 are short-circuited, and the charge accumulated in the OLED element 420 is discharged. Then, in the light emitting period _{T EL,} TFT 401 as shown in FIG. 42, and 403 to 405 is one which in the off state, TFT 402 is turned on, electric charge Q4 as described above to the OLED element 420 is supplied.

According to this embodiment, as in the second, fourth and sixth embodiments, since the discharging charges accumulated in the OLED device 420, the state of the OLED element 420 in the previous emission period _{T EL,} the current The display luminance in the light emission period _TEL can be prevented from being affected. As a result, it is possible to display accurate luminance, and display quality can be improved. In addition, since the charge accumulated in the OLED element 420 is discharged at the same time during the period in which the charge is transferred between the first capacitor element 410 and the second capacitor element 411, a separate operation period is provided. In comparison, sufficient time can be allocated to the initialization period _Tinit .

  Note that the scanning signal Yi may be used instead of the discharge control signal Vdis-i. In this case, since it is not necessary to generate the discharge control signal Vdis-i by the scanning line driving circuit 100, the configuration of the scanning line driving circuit 100 can be simplified, and the discharge control line 103 is omitted. Therefore, the wiring structure can be simplified.

  In each of the above-described embodiments, the OLED element 420 uses a light emitting organic material such as a low molecule, a polymer, or a dendrimer. The OLED element 420 is an example of a current driven element. Instead, an inorganic EL element, a field emission (FE) element, a surface conduction emission (SE) element, a ballistic electron emission (BS) element, an LED Other self-luminous elements such as electrophoretic elements and electrochromic elements may also be used. The present invention can also be applied to electro-optical devices such as write heads used in optical writing type printers and electronic copying machines, as in the above embodiments.

<9. Electronic equipment>
Next, an electronic apparatus to which the electro-optical device 10 according to the first to eighth embodiments described above is applied will be described. FIG. 43 shows a configuration of a mobile personal computer to which the electro-optical device 10 is applied. The personal computer 2000 includes an electro-optical device 10 as a display unit and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002. Since the electro-optical device 10 uses the OLED element 420, it is possible to display an easy-to-see screen with a wide viewing angle.
FIG. 44 shows a configuration of a mobile phone to which the electro-optical device 10 is applied. A cellular phone 3000, a plurality of operation buttons 3001, scroll buttons 3002, and the electro-optical device 10 as a display unit are provided. By operating the scroll button 3002, the screen displayed on the electro-optical device 10 is scrolled.
FIG. 45 shows the configuration of a personal digital assistant (PDA) to which the electro-optical device 10 is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and the electro-optical device 10 as a display unit. When the power switch 4002 is operated, various types of information such as an address book and a schedule book are displayed on the electro-optical device 10.
In addition, as an electronic device to which the electro-optical device 10 is applied, in addition to those shown in FIGS. 43 to 45, a digital still camera, a liquid crystal television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, Examples include electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, and devices equipped with touch panels. The electro-optical device 10 described above can be applied as a display unit of these various electronic devices. In addition, it is not limited to a display unit of an electronic device that directly displays an image or a character, but is applied as a light source of a printing device that is used to indirectly form an image or a character by irradiating light to the photosensitive member. Also good.

1 is a block diagram illustrating a configuration of an electro-optical device according to a first embodiment of the invention. FIG. It is a figure which shows the pixel circuit 400A of the same apparatus. It is a timing chart which shows operation | movement of the apparatus. It is an operation explanatory view of the pixel circuit 400A. It is an operation explanatory view of the pixel circuit 400A. It is a figure which shows the pixel circuit 400B used for the electro-optical apparatus which concerns on 2nd Embodiment of this invention. It is a timing chart which shows operation | movement of the apparatus. It is an operation explanatory view of the pixel circuit 400B. It is an operation explanatory view of the pixel circuit 400B. It is an operation explanatory view of the pixel circuit 400B. It is a figure which shows the pixel circuit 400C used for the electro-optical apparatus which concerns on 3rd Embodiment of this invention. It is a timing chart which shows operation | movement of the apparatus. It is an operation explanatory view of the pixel circuit 400C. It is an operation explanatory view of the pixel circuit 400C. It is an operation explanatory view of the pixel circuit 400C. It is a figure which shows pixel circuit 400D used for the electro-optical apparatus which concerns on 4th Embodiment of this invention. It is a timing chart which shows operation | movement of the apparatus. It is an operation explanatory view of the pixel circuit 400D. It is an operation explanatory view of the pixel circuit 400D. It is an operation explanatory view of the pixel circuit 400D. It is an operation explanatory view of the pixel circuit 400D. It is a figure which shows the pixel circuit 400E used for the electro-optical apparatus which concerns on 5th Embodiment of this invention. It is a timing chart which shows operation | movement of the apparatus. FIG. 46 is an explanatory diagram of the operation of the pixel circuit 400E. FIG. 46 is an explanatory diagram of the operation of the pixel circuit 400E. FIG. 46 is an explanatory diagram of the operation of the pixel circuit 400E. It is a figure which shows the pixel circuit 400F used for the electro-optical apparatus which concerns on 6th Embodiment of this invention. It is a timing chart which shows operation | movement of the apparatus. It is an operation explanatory diagram of the pixel circuit 400F. It is an operation explanatory diagram of the pixel circuit 400F. It is an operation explanatory diagram of the pixel circuit 400F. It is an operation explanatory diagram of the pixel circuit 400F. It is a figure which shows the pixel circuit 400G used for the electro-optical apparatus which concerns on 7th Embodiment of this invention. It is a timing chart which shows operation | movement of the apparatus. It is an operation explanatory view of the pixel circuit 400G. It is an operation explanatory view of the pixel circuit 400G. It is an operation explanatory view of the pixel circuit 400G. It is a figure which shows the pixel circuit 400H used for the electro-optical apparatus which concerns on 8th Embodiment of this invention. It is a timing chart which shows operation | movement of the apparatus. It is an operation explanatory diagram of the pixel circuit 400H. It is an operation explanatory diagram of the pixel circuit 400H. It is an operation explanatory diagram of the pixel circuit 400H. It is a figure which shows the personal computer using the same electro-optical apparatus. It is a figure which shows the mobile telephone using the same electro-optical apparatus. It is a figure which shows the portable information terminal using the same electro-optical apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electro-optical apparatus, 100 ... Scanning line drive circuit (drive means), 200 ... Data line drive circuit (drive means), 400A-400H ... Pixel circuit, 401 ... TFT (input switching means), 402 ... TFT (1st Switching means), 403 ... TFT (discharge means), 404 ... TFT (second switching means), 405 ... TFT (third switching means), 410 ... First capacitor element (first charge holding means), 411 ... Second Capacitance element (second charge holding means) 420... OLED element (electro-optic element), Vdata... Gradation voltage, Vinit... Initialization voltage (third voltage), VC... Charge holding reference voltage (second voltage), VR ... second low potential side voltage (fourth voltage), Yi ... scanning signal (selection signal), Vg-i ... light emission control signal (first control signal), Gini1-i ... first initialization signal (second control signal) ), Gini2-i ... Second initialization signal (third control signal), Vdis-i ... discharge control signal, Z1 ... first connecting point, Z2 ... second connecting _{point, T init ...} initialization period, _{T WRT ...} write _{period, T EL} ... light emission period.

Claims (18)

An input terminal;
A first power supply terminal to which a first voltage is supplied;
A second power supply terminal to which a second voltage is supplied;
An electro-optic element that is connected to the first power supply terminal and emits light of a light amount corresponding to the amount of charge supplied;
First charge holding means provided between the second power supply terminal and the first connection point for holding charge;
Second charge holding means provided between the first connection point and the second connection point for holding charge;
An input switching means provided between the input terminal and the second connection point, wherein an on state and an off state are controlled based on a selection signal;
A first switching means provided between the first connection point and the electro-optic element, wherein an on state and an off state are controlled based on a first control signal;
With electronic circuit. A third power supply terminal to which a third voltage is supplied;
A second switching means provided between the third power supply terminal and the second connection point, wherein an on state and an off state are controlled based on a second control signal;
The electronic circuit according to claim 1, further comprising: A fourth power supply terminal to which a fourth voltage is supplied;
A third switching means provided between the fourth power supply terminal and the first connection point, wherein an on state and an off state are controlled based on a third control signal;
The electronic circuit according to claim 2, further comprising:   4. The electronic circuit according to claim 1, further comprising a discharge unit that discharges the electric charge accumulated in the electro-optical element. 5. An input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, and a light having a light amount corresponding to the amount of electric charge supplied to the first power supply terminal. Between the first connection point and the first connection point provided between the second power supply terminal and the first connection point and holding the charge. A second charge holding means for holding charge; an input switching means provided between the input terminal and the second connection point; and provided between the first connection point and the electro-optic element. A control method of an electronic circuit comprising the first switching means,
In an initialization period, a third voltage is supplied to the input terminal, and the input switching means and the first switching means are controlled to be in an on state,
In the writing period, a gradation voltage corresponding to a gradation to be displayed is supplied to the input terminal, and the input switching unit is turned on and the first switching unit is turned off.
In the light emission period, the input switching means is controlled to be in an off state, and the first switching means is controlled to be in an on state.
A method for controlling an electronic circuit. An input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, a third power supply terminal to which a third voltage is supplied, and the first power supply terminal are connected. An electro-optical element that emits light of a light amount corresponding to the amount of charge supplied; a first charge holding unit that is provided between the second power supply terminal and the first connection point; A second charge holding means provided between the first connection point and the second connection point for holding charge; an input switching means provided between the input terminal and the second connection point; An electronic circuit comprising: a first switching means provided between one connection point and the electro-optic element; and a second switching means provided between the third power supply terminal and the second connection point. A control method,
In the initialization period, control is performed so that the first switching means and the second switching means are turned on,
In the writing period, a gradation voltage corresponding to the gradation to be displayed is supplied to the input terminal, the input switching means is turned on, and the first switching means and the second switching means are turned off. Control to
In the light emission period, control is performed so that the first switching means is turned on and the input switching means and the second switching means are turned off.
A method for controlling an electronic circuit. An input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, a third power supply terminal to which a third voltage is supplied, and a fourth voltage are supplied. Provided between a fourth power supply terminal, an electro-optical element connected to the first power supply terminal and emitting light of a light amount corresponding to the supplied charge amount, and the second power supply terminal and the first connection point. First charge holding means for holding charge; second charge holding means for holding charge provided between the first connection point and the second connection point; the input terminal and the second connection point; Input switching means provided between the first connection point and the electro-optic element, and provided between the third power supply terminal and the second connection point. Second switching means provided between the fourth power supply terminal and the first connection point. A control method of an electronic circuit and a third switching means,
In the initialization period, control is performed so that the first switching means is turned off, and the second switching means and the third switching means are turned on,
In the writing period, a gradation voltage corresponding to the gradation to be displayed is supplied to the input terminal, the input switching means is turned on, and the first switching means, the second switching means, and the third switching Control the means to turn off,
In the light emission period, the first switching unit is turned on, and the input switching unit, the second switching unit, and the third switching unit are controlled to be turned off.
A method for controlling an electronic circuit.   The electronic circuit includes discharge means for discharging the charge accumulated in the electro-optic element, and the charge accumulated in the electro-optic element during part or all of the period other than the period in which the first switching means is turned on. 8. The method of controlling an electronic circuit according to claim 5, wherein the discharging means is controlled so as to discharge the electric circuit. A plurality of pixel circuits;
Driving means for driving each of the plurality of pixel circuits,
Each of the plurality of pixel circuits is
An input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, and a light having a light amount corresponding to the amount of electric charge supplied to the first power supply terminal. Between the first connection point and the first connection point provided between the second power supply terminal and the first connection point and holding the charge. A second charge holding means for holding charge, an input switching means provided between the input terminal and the second connection point, the on-state and the off-state being controlled based on a selection signal; A first switching means provided between a first connection point and the electro-optic element, wherein an on state and an off state are controlled based on a first control signal;
The driving means includes
In the initialization period, the first voltage is supplied to the input terminal, the selection signal for turning on the input switching means is supplied to the input switching means, and the first switching means is turned on. Supplying a control signal to the first switching means;
In a writing period, a gradation voltage corresponding to a gradation to be displayed is supplied to the input terminal, the selection signal for turning on the input switching means is supplied to the input switching means, and the first switching means Supplying the first control signal to turn off the first switching signal to the first switching means;
Supplying the selection signal for turning off the input switching means to the input switching means and supplying the first control signal for turning on the first switching means to the first switching means during a light emission period; An electro-optical device. A plurality of pixel circuits;
Driving means for driving each of the plurality of pixel circuits,
Each of the plurality of pixel circuits is
An input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, a third power supply terminal to which a third voltage is supplied, and the first power supply terminal are connected. An electro-optical element that emits light of a light amount corresponding to the amount of charge supplied; a first charge holding unit that is provided between the second power supply terminal and the first connection point; Provided between the first connection point and the second connection point, the second charge holding means for holding electric charge, and provided between the input terminal and the second connection point, and turned on based on the selection signal And an input switching means for controlling the off-state, and a first switching means provided between the first connection point and the electro-optic element, the on-state and the off-state being controlled based on a first control signal; , Provided between the third power supply terminal and the second connection point, and a second control And a second switching means on and off states are controlled based on the item,
The driving means includes
In the initialization period, control is performed so that the first switching means and the second switching means are turned on,
In the writing period, a gradation voltage corresponding to the gradation to be displayed is supplied to the input terminal, the input switching means is turned on, and the first switching means and the second switching means are turned off. Control to
In the light emission period, control is performed so that the first switching means is turned on and the input switching means and the second switching means are turned off.
An electro-optical device. A plurality of pixel circuits;
Driving means for driving each of the plurality of pixel circuits,
Each of the plurality of pixel circuits is
An input terminal, a first power supply terminal to which a first voltage is supplied, a second power supply terminal to which a second voltage is supplied, a third power supply terminal to which a third voltage is supplied, and a fourth voltage are supplied. Provided between a fourth power supply terminal, an electro-optical element connected to the first power supply terminal and emitting light of a light amount corresponding to the supplied charge amount, and the second power supply terminal and the first connection point. First charge holding means for holding charge; second charge holding means for holding charge provided between the first connection point and the second connection point; the input terminal and the second connection point; Provided between the first switching point and the electro-optic element, and is turned on based on the first control signal. A first switching means for controlling a state and an off state, the third power supply terminal, and the Provided between the second connection point, the second switching means for controlling the on state and the off state based on the second control signal, and provided between the fourth power supply terminal and the first connection point, A third switching means for controlling an on state and an off state based on a third control signal;
The driving means includes
In the initialization period, the first control signal for turning off the first switching means is supplied to the first switching means, and the second control signal for turning on the second switching means is supplied to the second switching means. Supply to the third switching means, the third control signal to turn on the third switching means,
In a writing period, a gradation voltage corresponding to a gradation to be displayed is supplied to the input terminal, the selection signal for turning on the input switching means is supplied to the input switching means, and the first switching means The first control signal for turning off the second switching means is supplied to the first switching means, the second control signal for turning off the second switching means is supplied to the second switching means, and the third switching means Supplying the third control signal to the third switching means to turn off the power supply,
Supplying the first control signal for turning on the first switching means to the first switching means and supplying the selection signal for turning off the input switching means to the input switching means during the light emission period; said second control signal to said second switching means in the oFF state is supplied to the second switching means, for supplying said third control signal to said third switching means in the oFF state to the third switching means,
An electro-optical device.   The electro-optical device according to claim 11, wherein the driving unit supplies the second control signal to the third switching unit instead of the third control signal. Each of the plurality of pixel circuits includes a discharge unit that discharges the electric charge accumulated in the electro-optical element,
The driving means controls the discharging means so as to discharge the charge accumulated in the electro-optic element in part or all of the period other than the period in which the first switching means is turned on;
The electro-optical device according to claim 9, wherein the electro-optical device is any one of the above. Each of the plurality of pixel circuits includes discharge switching means that is connected in parallel with the electro-optical element and that is controlled to be turned on and off based on a discharge control signal.
The driving means supplies the selection signal as the discharge control signal to the switching means for discharge.
The electro-optical device according to claim 10 , wherein the electro-optical device is any one of the above. Supplying the first voltage to the second power supply terminal;
The electro-optical device according to claim 9, wherein the electro-optical device is any one of claims 9 to 14. Supplying either the first voltage or the second voltage to the third power supply terminal;
The electro-optical device according to claim 10, wherein the electro-optical device is any one of the above. Supplying either the first voltage, the second voltage, or the third voltage to the fourth power supply terminal;
The electro-optical device according to claim 11 or 12,   An electronic apparatus comprising the electro-optical device according to claim 9.

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