JP2011095644A - Light emitting device and method of driving the same, and electronic apparatus - Google Patents

Abstract

The luminance of a light emitting device is improved.
A light emitting device includes a scanning line, a signal line, a unit circuit, and a first switching element connected between the data side driving circuit and the signal line. . The unit circuit includes a capacitive element C1 having the light emitting element 8, and the first electrode E1 and the second electrode E2 connected to the signal line 6. In the first period Pw, the first switching element SSW is turned on, and the data potential VD is supplied from the data side driving circuit 500 to the second electrode E2 and the signal line 6. Then, in the second period Ps, the potential of the first electrode E1 is shifted.
[Selection] Figure 2

Description

  The present invention relates to a light emitting device using a light emitting element, a driving method thereof, and an electronic apparatus.

In recent years, various light emitting devices using light emitting elements such as organic light emitting diode (hereinafter referred to as “OLED”) elements called organic EL (Electro Luminescence) elements and light emitting polymer elements have been proposed.
This light emitting device includes various drive circuits for supplying a predetermined current or voltage to the OLED element or the like. Such a drive circuit may include, for example, a capacitive element connected in parallel to the OLED element.
In this case, a data potential may be supplied to the anode of the OLED element and one electrode of the capacitor, and a reference potential may be supplied to the cathode of the OLED element and the other electrode of the capacitor. In this case, the organic EL element can be stably driven by supplying the OLED element with a current caused by the electric charge corresponding to the data potential stored in the capacitor element.
As such a light emitting device, for example, a device disclosed in Patent Document 1 is known.

JP 2000-122608 A

  However, in the configuration of Patent Document 1, it is necessary to sufficiently secure the light emission time of the OLED element in order to set the light emission amount (time integration value of light emission luminance) of the OLED element to a sufficient value. Therefore, it is necessary to set the capacitance of the capacitive element to a very large value.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A plurality of scanning lines, a plurality of signal lines, a plurality of unit circuits provided corresponding to intersections of the plurality of scanning lines and the plurality of signal lines, and the plurality of signal lines A first switching element connected between the first signal line and the data side driving circuit, wherein each of the plurality of unit circuits includes a light emitting element, a first electrode, and a second electrode. A capacitive element, a second switching element connected between the first signal line and the light emitting element, and a third connected between the first signal line and the second electrode. A light emitting device driving method comprising: turning on a predetermined third switching element among the third switching elements belonging to the plurality of unit circuits in a first period; The first switching element is turned on; A data potential is supplied from the data side driving circuit to the first signal line, and the first switching element and the second switching element are turned off in the second period after the first period. A light emitting device that shifts the potential of the first electrode of the capacitor element and connects the signal line to the light emitting element via the second switching element in a third period after the second period. Driving method.

  According to this, the load when the data side driving circuit supplies the data potential to the signal line can be reduced. Therefore, power consumption can be reduced when the light-emitting element emits light with the same luminance. In other words, the luminance of the light emitting element can be increased when the same data potential is supplied.

Application Example 2 A driving method of a light emitting device according to the application example, wherein the light emitting element includes an anode and a cathode, and the anode is connected to the second switching element. A method for driving a light emitting device, wherein a transition is made from a state in which a first potential is supplied to the first electrode of the capacitor to a state in which a second potential higher than the first potential is supplied in a period.
According to this, a potential difference between the cathode and the second electrode can be secured, and the luminance of the light emitting element can be increased.

[Application Example 3] A driving method of a light emitting device according to Application Example 1, wherein the light emitting element includes an anode and a cathode, and the cathode is connected to the second switching element. A method for driving a light emitting device, wherein a transition is made from a state in which a first potential is supplied to the first electrode of the capacitor element to a state in which a second potential lower than the first potential is supplied in two periods.
According to this, a potential difference between the anode and the second electrode can be secured, and the luminance of the light emitting element can be increased.

Application Example 4 In the driving method of the light emitting device according to the application example, the second potential is supplied to the first electrode of the capacitive element in a fourth period after the third period. A method for driving a light emitting device, wherein the first potential is changed to a supplied state, and the second switching element is turned on before and after the transition.
According to this, a reverse bias can be applied to the light emitting element in the fourth period.

  Application Example 5 A plurality of scanning lines, a plurality of signal lines, a plurality of unit circuits provided corresponding to intersections of the plurality of scanning lines and the plurality of signal lines, and the plurality of scanning lines A scanning side driving circuit connected to the plurality of signal lines; and a data side circuit connected to the plurality of signal lines, wherein the data side circuit includes the data side driving circuit, the data side driving circuit, and the plurality of signal lines. A first switching element connected to the first signal line, and each of the plurality of unit circuits includes a light emitting element, a first electrode, and a second electrode. A second switching element connected between the first signal line and the light emitting element, and a third switching element connected between the first signal line and the second electrode. , And each of the plurality of scanning lines controls the third switching element. A first control line for supplying a first control signal, a second control line for supplying a second control signal for controlling the second switching element, and a third control signal connected to the first electrode. A light-emitting device, wherein the scanning-side control circuit generates the third control signal as a signal in association with the second control signal.

  According to this, the 1st electrode of a capacitive element can be controlled using the 3rd control signal which is a signal linked with the 2nd control signal. Therefore, the potential control of the first electrode of the capacitive element can be performed in synchronization with the charge / discharge operation of the capacitive element by the third switching element. Therefore, the light emitting device can be easily controlled.

Application Example 6 In the light emitting device according to the application example, the scanning-side control circuit generates the third control signal so as to have a number of pulses corresponding to a pulse width of the second control signal. , Light emitting device.
According to this, the number of potential shift operations of the first electrode of the capacitive element can be controlled according to the second control signal pulse width.

Application Example 7 In the light emitting device according to the application example described above, the scanning-side control circuit includes a shift transfer circuit, and the second control signal and the third control signal are based on an output of the shift transfer circuit. A light emitting device that is produced or controlled.
According to this, since the second control signal and the third control signal can be generated from the output of one shift transfer circuit, the circuit can be simplified or downsized.

Application Example 8 Electronic equipment including the light emitting device described in the application example.
Light emitting devices are used in various electronic devices. A typical example of an electronic device is a device that uses a light-emitting device as a display device. Examples of the electronic apparatus according to this application example include a personal computer and a mobile phone. However, the use of the light-emitting device according to this application example is not limited to image display. For example, the light emitting device of this application example can also be used as an exposure device (optical head) for forming a latent image on an image carrier such as a photosensitive drum by irradiation of light.

  According to this, since the electronic device of this application example includes the various light emitting devices described above, it is possible to increase the brightness of the entire image or reduce the power consumption.

1 is a block diagram illustrating a light emitting device according to a first embodiment of the present invention. FIG. 2 is a circuit diagram illustrating details of a unit circuit, a scanning side driving circuit, and a data side driving circuit constituting the light emitting device of FIG. 1. 3 is a timing chart for explaining the operation of the light emitting device of FIGS. 1 and 2. It is a circuit diagram which shows the detail of a scanning side drive circuit. It is a circuit diagram which shows the detail of the scanning side drive circuit concerning a modification. It is a circuit diagram of the unit circuit concerning a modification. It is a perspective view which shows the electronic device to which the light-emitting device which concerns on 1st Embodiment of this invention is applied. It is a perspective view which shows the other electronic device to which the light-emitting device which concerns on 1st Embodiment of this invention is applied. It is a perspective view which shows the further another electronic device to which the light-emitting device which concerns on 1st Embodiment of this invention is applied.

<First Embodiment>
Hereinafter, a first embodiment according to the present invention will be described with reference to FIGS. 1, 2, 3, and 4. In FIG. 3, Va [j] is the potential of the signal line 6 in the j-th column (see FIG. 1). In addition to FIGS. 1, 2, 3, and 4 referred to here, in each drawing referred to below, the ratio of dimensions of each part may be appropriately different from the actual one. .

  In FIG. 1, a light emitting device 10 is a device employed in various electronic devices as a means for displaying an image, and includes a pixel array unit 100 in which a plurality of unit circuits P1 are arranged in a plane, a scanning side drive circuit. 200, a data side circuit 300, and a processing circuit 400. In FIG. 1, the scanning side driving circuit 200 and the data side circuit 300 are illustrated as separate circuits, but a configuration in which a part or all of these circuits are a single circuit is also employed. .

  As shown in FIG. 1, the pixel array unit 100 is provided with m scanning lines 3 extending in the X direction and n signal lines 6 extending in the Y direction orthogonal to the X direction ( m and n are natural numbers). Each unit circuit P <b> 1 is disposed at a position corresponding to the intersection of the scanning line 3 and the signal line 6. Therefore, these unit circuits P1 are arranged in a matrix of m rows × n columns.

  Of the above configuration, each of the m scanning lines 3 includes a set of three wires as shown in FIGS. 1 and 2. Here, the set of three wires is a first control line 3W, a second control line 3C, and a third control line 3B, as shown in FIGS. That is, if there are m scanning lines 3, the total number of first control lines 3W, second control lines 3C, and third control lines 3B is 3m. Each of these control lines (3W, 3C, 3B) is connected to each of the unit circuits P1 located in each row (more specific connection modes will be described later with reference to FIG. 2).

The processing circuit 400 supplies a signal for controlling the driving circuit such as a start pulse and a clock signal and image data to the scanning side driving circuit 200 and the data side circuit 300 to control both driving circuits.
As shown in FIG. 2, the scanning side drive circuit 200 shown in FIG. 1 includes first control signals GW [1] to GW [m], second control signals GC [1] to GC [m], and third control signals. GB [1] to GB [m] are generated. The scanning side drive circuit 200 shown in FIG. 1 is provided with a plurality of circuits corresponding to the scanning lines 3 as shown in FIG.

  A circuit corresponding to the scanning line 3 of the i-th row (i is an integer satisfying 1 ≦ i ≦ m) of the scanning side driving circuit 200 is shown in FIGS. As shown in FIG. 2, the circuit corresponding to the i-th scanning line 3 includes a first shift transfer circuit 210, a first output circuit 220, a second shift transfer circuit 230, a second output circuit 240, and a third output circuit. 250.

  The scanning side drive circuit 200 generates first control signals GW [1] to GW [m] that are sequentially activated, and outputs them to each of the first control lines 3W described above. Of the first control signal GW [i] supplied to the first control line 3W included in the scanning line 3 in the i-th row (i is an integer satisfying 1 ≦ i ≦ m), the first control signal GW [i]. The transition to the active state means selection of n unit circuits P1 belonging to the i-th row. The first shift transfer circuit 210 is a part of a unit circuit constituting a shift register that sequentially transfers start pulses and outputs control pulses. The first output circuit 220 receives the output of the first shift transfer circuit 210 and outputs the first control signal GW [i] shown in FIG. For example, the output of the first shift transfer circuit 210 is a signal having a pulse width corresponding to the unit period “1H” in FIG. 3, and the first output circuit 220 determines the pulse width of the output of the first shift transfer circuit 210. The first control signal GW [i] shown in FIG. 3 may be narrowed and output to the first control line 3W. The first output circuit 220 may boost the output of the first shift transfer circuit 210 and output the boosted output to the first control line 3W.

  As shown in FIG. 3, the scanning side drive circuit 200 generates second control signals GC [1] to GC [m] that are appropriately activated, and outputs them to each of the second control lines 3C described above. Of the second control signal GC [i] supplied to the second control line 3C included in the i-th scanning line 3, the transition of the second control signal GC [i] to the active state is the i-th row. This means permission to charge a later-described capacitive element C1 included in the n unit circuits P1 to which it belongs. Similar to the first shift transfer circuit 210, the second shift transfer circuit 230 is a part of a unit circuit constituting a shift register that sequentially transfers start pulses and outputs control pulses. The second output circuit 240 receives the output of the second shift transfer circuit 230 and outputs the second control signal GC [i]. In FIG. 3, the second control signal GC [i] has a pulse width corresponding to two unit periods “1H”. The second output circuit 240 may boost the output of the second shift transfer circuit 230 and output it to the second control line 3C.

The scanning side drive circuit 200 generates third control signals GB [1] to GB [m] that are appropriately activated and outputs the third control signals GB [m] to each of the third control lines 3B. Of the third control signal GB [i] supplied to the third control line 3B included in the i-th scanning line 3, the potential of the third control signal GB [i] is n pieces of the number belonging to the i-th row. It is supplied to one electrode of a later-described capacitor C1 included in the unit circuit P1.
The third output circuit 250 receives the second control signal GC [i] and outputs the third control signal GB [i] shown in FIG. For example, the third output circuit 250 may include a control circuit 260 and a selector 270, as shown in FIG.

The control circuit 260 may hold the second control signal GC [i]. According to this, it is possible to control the selector 270 according to the second control signal GC [i] and output the third control signal GB [i]. Further, if the second control signal GC [i] does not transition, the selector 270 maintains the state, so that power consumption can be reduced.
The control circuit 260 is a latch circuit, and the latch circuit may include an inverter and a clocked inverter in which the output of the inverter is connected to the input and the input of the inverter is connected to the output.
The control circuit 260 outputs a signal that becomes active every time the second control signal GC [i] transitions from inactive to active, and is non-switched every time the second control signal GC [i] transitions from active to inactive. An active signal may be output, and the state may be maintained as it is if there is no transition in the second control signal GC [i].

  When the second control signal GC [i] transitions, the control circuit 260 operates. Since the number of operations can be reduced, power consumption of the control circuit 260 and the selector 270 can be reduced. Further, the third control signal GB [i] may be a signal obtained by narrowing the pulse width of the second control signal GC [i] as shown in FIG. Further, as shown in FIG. 3, the third control signal GB [i] may have a number of pulses corresponding to the pulse width of the second control signal GC [i].

For example, in FIG. 3, since the second control signal GC [i] has a pulse width corresponding to two unit periods “1H”, the number of pulses of the third control signal GB [i] is 2. is there. In FIG. 3, the third control signal GB [i] has an active period with a pulse width equal to or greater than a time width obtained by adding a potential shift period Ps and a driving period Pd, which will be described later. The signal does not overlap Pw.
2 and 4, the second control signal GC [i] is input to the control circuit 260. However, the output of the second shift transfer circuit 230 may be input to the control circuit 260. The selector 270 selects either the high potential VH or the low potential VL according to the output from the control circuit 260 and supplies it to the third control line 3B.

  As described above, two signals are generated using one output from the second shift transfer circuit 230. Here, the two signals are the second control signal GC [i] and the third control signal GB [i]. The third control signal GB [i] is a signal associated with the second control signal GC [i].

  Here, each of the first shift transfer circuit 210 and the second shift transfer circuit 230 has a shift register, but the second shift transfer circuit 230 may be omitted. In this case, the output of the first shift transfer circuit 210 may be input to a predetermined logic circuit, and the second control signal GC [i] shown in FIG. 3 may be generated by the predetermined logic circuit. . However, if the second shift transfer circuit 230 is provided separately from the first shift transfer circuit 210, the second control signal GC [i] and the third control signal GB [i] are independent of the first control signal GW [i]. Can be generated, increasing the degree of freedom of control. In particular, the second control signal GC [i] and the third control signal GB [i] control a capacitive element C1, which will be described later, and greatly affect the light emission luminance, and therefore, separate from the first shift transfer circuit 210. A second shift transfer circuit 230 is preferably provided.

  A data side circuit 300 illustrated in FIGS. 1 and 2 includes a data side driving circuit 500, sampling switches SSW [1] to SSW [n], and the like. Based on the image data supplied from the processing circuit 400, the data side circuit 300 corresponds to the grayscale data of each of the n unit circuits P1 corresponding to the first control lines 3W selected by the scanning side drive circuit 200. The data potentials VD [1] to VD [n] are generated by the data side driving circuit 500 and supplied to the sampling switches SSW [1] to SSW [n] of each column. Further, the data side driving circuit 500 generates the fourth control signals GS [1] to GS [n] and supplies them to the corresponding sampling switches SSW [1] to SSW [n].

  When the fourth control signals GS [1] to GS [n] transition to the active state, the sampling switches SSW [1] to SSW [n] are turned on and output to the signal lines 6. When the fourth control signals GS [1] to GS [n] transition to the inactive state, the sampling switches SSW [1] to SSW [n] are turned off, and the signal lines 6 and the data side driving circuit 500 are not conductive. It becomes.

  Here, the fourth control signals GS [1] to GS [n] supplied to the sampling switches SSW [1] to SSW [n] in each column may transition to the active state at the same timing. 4 The control signals GS [1], GS [2],... GS [n] may be shifted to the active state in this order. If the transition is made to the active state at the same timing, the period during which the data potentials VD [1] to VD [n] are output to each signal line 6 can be ensured as compared with the case where the transition is made sequentially to the active state. Hereinafter, the data potential VD output to the signal line 6 in the j-th column (j is an integer satisfying 1 ≦ j ≦ n) may be referred to as VD [j].

Details of each unit circuit P1 will be described with reference to FIG.
As shown in FIG. 2, each unit circuit P1 includes a light emitting element 8, a capacitive element C1, a first transistor Tr1, and a second transistor Tr2.

  The light emitting element 8 is an OLED (Organic Light Emitting Diode) element in which a light emitting layer of an organic EL material is interposed between an anode and a cathode. As shown in FIG. 2, the light emitting element 8 is disposed between the second transistor Tr2 and a constant potential line (ground line) to which a constant potential is supplied. Here, the anode is provided for each unit circuit P1 and is an individual electrode controlled for each unit circuit P1, and the cathode is a common electrode provided in common for the unit circuit P1. The cathode is connected to a constant potential line to which a constant potential is supplied. The constant potential line (ground line) may be configured only by the common electrode (cathode) itself provided in common to the plurality of unit circuits P1 in the pixel array unit 100, or connected to the common electrode (cathode). Wiring may be provided. The anode may be a common electrode and the cathode may be an individual electrode.

  The capacitor C1 holds the data potential VD [j] supplied from the signal line 6. As shown in FIG. 2, the capacitive element C1 includes a first electrode E1 connected to the third control line 3B and a second electrode E2 connected to the first transistor Tr1. The potential of the second electrode E2 of the capacitive element C1 is controlled by the third control signal GB [i].

  The first transistor Tr1 is a switching element that conducts the second electrode E2 of the capacitive element C1 and the signal line 6 by conducting when the second control line 3C is selected. As shown in FIG. 2, one of the source and the drain of the first transistor Tr1 is connected to the second electrode E2 of the capacitor C1, and the other of the source and the drain is connected to the signal line 6.

  The gate of the first transistor Tr1 is connected to the second control line 3C. Thus, when the second control signal GC [i] transitions to the active state, the first transistor Tr1 belonging to the i-th row is turned on, and the second electrode E2 and the signal line 6 are electrically connected, while the second When the control signal GC [i] transitions to the inactive state, the first transistor Tr1 belonging to the i-th row is turned off, and the second electrode E2 and the signal line 6 are brought out of conduction.

  The second transistor Tr2 is a switching element that conducts the signal line 6 and the light emitting element 8 by conducting when the first control line 3W is selected. As shown in FIG. 2, one of the source and the drain of the second transistor Tr <b> 2 is connected to the anode of the light emitting element 8, and the other of the source and the drain is connected to the signal line 6.

  The gate of the second transistor Tr2 is connected to the first control line 3W. Thus, when the first control signal GW [i] transitions to the active state, the second transistor Tr2 belonging to the i-th row is turned on, and the signal line 6 and the light emitting element 8 are brought into conduction, while the first control signal When the signal GW [i] transitions to the inactive state, the second transistor Tr2 is turned off, and the signal line 6 and the light emitting element 8 are brought out of conduction.

Next, an example of operation | movement thru | or an effect | action of the light-emitting device 10 which concerns on 1st Embodiment is demonstrated, referring FIG. 3 in addition to FIG.1 and FIG.2 already referred.
The light emitting device 10 is basically based on the following three periods [i] [ii] [iii].

[I] Writing period Pw
In this writing period Pw, a writing operation is performed. In this writing operation, the data potential VD [j] corresponding to the light emission gradation of the light emitting element 8 included in each unit circuit P1 corresponding to a certain scanning line 3 is applied to the unit circuit P1 belonging to the column including the light emitting element 8. The operation of holding the capacitor element C1 and the signal line 6 is performed.

  First, the data side driving circuit 500 shifts the fourth control signals GS [1] to GS [n] to the active state, and turns on the corresponding sampling switches SSW [1] to SSW [n]. Thereby, the data side drive circuit 500 is connected to each signal line 6 through the sampling switches SSW [1] to SSW [n]. Then, the data potentials VD [1] to VD [n] corresponding to the gradation data of the n unit circuits P1 corresponding to the selected first control line 3W are output to the corresponding signal lines 6. The In the leftmost writing period Pw in FIG. 3, the data potential VD [j] corresponds to the light emitting element 8 in each unit circuit P1 located in the first row (in FIG. 3, “GW [1]”). (See wording “corresponding” to “corresponding to GW [4]”).

Further, if the second control signal GC [i] is in an active state in the writing period Pw, the second electrode E2 of the capacitive element C1 of the unit circuit P1 in this i row is connected to the signal line 6, and the capacitive element Data potentials VD [1] to VD [n] are held in C1.
For example, the data potential VD [3] (see FIG. 1) for the light emitting element 8 corresponding to the scanning line 3 in the second row and located in the third column is each of the data potential VD [3] (see FIG. 1). It is held by a plurality of capacitive elements C1 in the unit circuit P1.

  In FIG. 3, the data potentials VD [1] to VD [n] in the first row are held in the capacitor elements C1 in the first row and the m-th row (not shown), and the data potential VD [ 1] to VD [n] are held in the capacitor elements C1 in the first and second rows, and the data potentials VD [1] to VD [n] in the third row are the capacitances in the second and third rows. It is held by the element C1. Here, when any light emitting element 8 emits light, two capacitor elements C1 are used in order to cause one light emitting element 8 to emit light. In this way, the number of capacitive elements C1 used is the same, and the capacitive element C1 is selected so that the positional relationship between these capacitive elements C1 and the light emitting element 8 used for the light emitting operation is substantially the same, and the data potential VD is held. Further, the two capacitive elements C1 are used to cause one light emitting element 8 to emit light. However, in order to adjust the luminance of the light emitting elements 8, the second control signal GC of the unit circuits P1 located in the same column is used. The number of capacitive elements C1 belonging to the unit circuit P1 that is activated by [1] to GC [m] may be set. If the number of capacitive elements C1 connected to the signal line 6 is large, the luminance is high, and if it is small, the luminance is low.

Furthermore, the first control signal GW [i] is in an inactive state, and the second transistor Tr2 is in an off state. Therefore, the capacitive element C1 and the signal line 6 are not connected to the light emitting element 8 and do not emit light.
In the write operation, the third control line 3B and the second electrode E2 of the capacitive element C1 are connected to the low potential line L1 via the selector 270. Therefore, the data potentials VD [1] to VD [n] are held with respect to the first potential VL when writing to the capacitor C1. In the write operation, the data potentials VD [1] to VD [n] can be charged with reference to the potential VL lower than that in the potential shift operation and the light emission operation described later. Electric power can be reduced. In practice, there is a parasitic capacitance between the signal line 6 and, for example, an electrode that becomes a common electrode of the light-emitting element 8. Therefore, it is necessary to take this parasitic capacitance into account. Can be ignored when is relatively smaller than the capacitance value of the capacitive element C1.

[Ii] Potential shift period Ps
Subsequently, a potential shift operation is performed in the potential shift period Ps after the writing period Pw. In the potential shift period Ps, an operation is performed in which the third control line 3B and the first electrode E1 of the capacitive element C1 are changed from being connected to the low potential line L1 to being connected to the high potential line L2. Therefore, the third control line 3B and the first electrode E1 of the capacitive element C1 transition from the first potential VL to the second potential VH. As a result, the potential of the second electrode E2 and the signal line 6 of the capacitive element C1 is shifted using capacitive coupling between the capacitance of the capacitive element C1 and the capacitance associated with the second electrode E2 of the capacitive element C1 or the signal line 6. To do.

  The second electrode E2 of the capacitive element C1 connected to the signal line 6 in the writing period Pw maintains the state of being connected to the signal line 6 even in the potential shift period Ps. That is, the first transistor Tr1 that is set to the on state in the write operation maintains the on state in the potential shift operation.

  From this state, the data side drive circuit 500 changes the fourth control signals GS [1] to GS [n] from the active state so that the sampling switches SSW [1] to SSW [n] are turned off from the on state. Transition to inactive state. The first control signal GW [j] is in an inactive state, and the second transistor Tr2 is in an off state. As a result, the second electrode E2 and the signal line 6 of the capacitive element C1 are not connected to the data side driving circuit 500 and the light emitting element 8, and the first electrode E1 and the signal line 6 of the capacitive element C1 are electrically connected. Floating.

Thereafter, the selector 270 is controlled by the control circuit 260, and the third control line 3B and the second electrode E2 of the capacitive element C1 are connected to the low potential line L1 via the selector 270, and then the high potential line L2. Transition to connected state.
As a result, the third control line 3B and the first electrode E1 of the capacitive element C1 transition from the first potential VL to the second potential VH. The potentials of the second electrode E2 and the signal line 6 of the capacitive element C1 are shifted using capacitive coupling between the capacitance of the capacitive element C1 and the capacitance associated with the second electrode E2 of the capacitive element C1 or the signal line 6. .

Here, the capacitance value of the parasitic capacitance associated with the second electrode E2 and the signal line 6 of the capacitive element C1 is negligibly small compared to the capacitance value of the capacitive element C1, and the second potential VH and the first potential VL are small. Is ΔV, the potential of the second electrode E2 and the signal line 6 of the capacitor C1 is shifted by ΔV from the data potentials VD [1] to VD [n] held in the writing operation.
Even if the capacitance value of the parasitic capacitance associated with the second electrode E2 and the signal line 6 of the capacitive element C1 is a certain level, charges are distributed according to the capacitance value of the parasitic capacitance and the capacitance value of the capacitive element C1. , The potential shifts. Here, the potential held in the capacitor C1 and the signal line 6 after the potential shift operation depends on not only ΔV but also the data potentials VD [1] to VD [n] held by the write operation. The luminance of the light emitting element 8 can be set according to the gradation data.

Since the third control signal GB [i] is a signal associated with the second control signal GC [i], the second control signal GC [supplied to the second control line 3C in the writing period Pw. When i] becomes active, the potential of only the third control line 3B included in the scanning line 3 is shifted, and the potentials of the other third control lines 3B are not shifted. Therefore, power consumption can be reduced as compared with the case where the potentials of all the third control lines 3B are shifted.
Here, since the electrode connected to the second transistor Tr2, in other words, the individual electrode is the anode, the second potential is changed from the first potential VL in the potential shift period Ps so as to increase the potential difference with the cathode that is the common electrode. Transitioned to VH. If the electrode connected to the second transistor Tr2, in other words, the individual electrode is a cathode, it is preferable to transition from the second potential VH to the first potential VL in the potential shift period Ps.

[Iii] Driving period Pd
Subsequently, the light emission operation is performed in the driving period Pd after the potential shift period Ps. This light emitting operation is an operation of causing the light emitting element 8 to emit light based on the potential held in the capacitor element C1 and the signal line 6 in the writing operation and the potential shift operation. In this operation, the unit circuit P1 including the light emitting element 8 supplies the first control signal GW [i] that is active to the first control line 3W included in the corresponding scanning line 3, and thereby the unit circuit P1 includes the unit circuit P1. It includes that the second transistor Tr2 in the circuit P1 becomes conductive. As a result, the light emitting element 8 is supplied with a current corresponding to the electric charge accumulated in the capacitive element C1 and the signal line 6, and emits light.

  Here, the second electrode E2 of the capacitor C1 connected to the signal line 6 in the writing operation and the potential shift operation maintains the state of being connected to the signal line 6 even in the light emission operation. That is, the first transistor Tr1 set to the on state in the writing operation and the potential shift operation maintains the on state. In the light emitting operation, the potentials of the third control line 3B and the first electrode E1 of the capacitive element C1 maintain the potential in the potential shift operation.

  Here, when the potential difference between the potential held in the capacitor element C1 and the signal line 6 and the potential of the common electrode exceeds the threshold value of the light emitting element 8, the light emitting element 8 emits light. Therefore, the higher the potential difference, the brighter the light emitting element 8 emits light. And when a potential difference is high, the electric charge charged in the meantime increases, and the light emitting element 8 light-emits brightly.

  In the first embodiment, since not only the data potentials VD [1] to VD [n] written by the write operation but also the potential shifted by the potential shift operation is used, the data potential VD [1 ] To VD [n] alone, the potential difference can be increased. Compared to the case where the same data potentials VD [1] to VD [n] are used, the light-emitting element 8 is common. A potential difference with respect to the potential of the electrode can be ensured, and light can be emitted brightly.

  Then, in order to end the light emitting operation of the light emitting element 8, the first control signal GW [i] which is inactive is supplied to the first control line 3W, thereby non-conducting the second transistor Tr2 in the unit circuit P1. Put it in a state. Here, in order to cause the light emitting element 8 to emit light brightly, the first control signal that is inactive after the potential difference falls below the threshold value of the light emitting element 8 due to the flow of electric charge to the light emitting element 8 and the light emission is completed. It is preferable to supply GW [i] to the first control line 3W.

  Thereafter, the state where the third control line 3B and the first electrode E1 of the capacitive element C1 are connected to the high potential line L2 is changed to a state where the third control line 3B and the first electrode E1 of the capacitive element C1 are connected to the low potential line L1 until the next row write operation is performed. Transition. Therefore, the second signal line 6B and the first electrode E1 of the capacitor C1 transition from the second potential VH to the first potential VL.

  The above operation example is merely an example. In the first embodiment, the manner in which the second control line 3C is selected according to the first control line 3W being selected line-sequentially can be appropriately set. The same applies to the third control line 3B.

  In the first embodiment, the potential difference between the signal line 6 and the common electrode is equal to or less than the threshold value of the light emitting element 8 in the driving period Pw at at least one data potential among the data potentials VD [j]. In the drive period Pd, it is preferable that the threshold value of the light emitting element 8 is set. According to this, the amplitude of the data potential VD [j] to be written in the writing period Pw can be made smaller than the reference potential.

  Therefore, power consumption in the writing period Pw can be reduced. In the case of the data potential VDk showing the highest luminance among the data potential VD [j], the potential difference between the signal line 6 and the common electrode is the threshold of the light emitting element 8 from the writing period Pw to the driving period Pd. It may be set to exceed the value. Of the data potential VD [j], the data potential VD1 indicating the lowest luminance may be lower than the ground potential. In addition, the data potential VD1 indicating the lowest luminance among the data potential VD [j] may be lower than the potential of the common electrode.

  Although the first embodiment according to the present invention has been described above, the light emitting device according to the first embodiment is not limited to the above-described form, and various modifications can be made.

(Modification 1)
After the second transistor Tr2 in the unit circuit P1 is made non-conductive in the driving period Pd of the first embodiment, the third control line 3B and the first electrode E1 of the capacitive element C1 are connected to the high potential line L2. The state is changed to a state connected to the low potential line L1. However, the present invention is not limited to this, and after the third control line 3B and the first electrode E1 of the capacitive element C1 are transitioned from the state connected to the high potential line L2 to the state connected to the low potential line L1, the unit circuit P1 The second transistor Tr2 may be turned off.

  At this time, as in the operation of the potential shift period Ps, the potentials of the second electrode E2 and the signal line 6 of the capacitive element C1 are associated with the capacitance of the capacitive element C1 and the second electrode E2 or the signal line 6 of the capacitive element C1. Shift using capacitive coupling by the capacity to be performed. At this time, a reverse bias may be applied to the light emitting element 8. Here, the potential of the second electrode E2 and the signal line 6 of the capacitive element C1 is set to be lower than the potential of the common electrode. Thereby, the characteristic deterioration of the light emitting element 8 when light is emitted by applying a forward bias to the light emitting element 8 can be recovered.

(Modification 2)
Instead of the circuit arrangement of FIG. 4 of the first embodiment, the circuit arrangement of FIG. 5 may be adopted. The difference from the first embodiment is that the first shift transfer circuit 210, the first output circuit 220, the second shift transfer circuit 230, and the second output circuit 240 are arranged on one side with respect to the pixel array unit 100, and The three-output circuit 250 is arranged on the opposite side across these circuits and the pixel array unit 100. That is, the scanning side driving circuit 200 is arranged on both sides of the pixel array unit 100. Here, the first shift transfer circuit 210 and the first output circuit 220 are arranged on one side of the pixel array unit 100, and the second shift transfer circuit 230, the second output circuit 240, and the third output circuit 250 are connected to the pixel. You may arrange | position to the other side of the array part 100. FIG.

(Modification 3)
In the first embodiment, the unit circuit P1 of FIG. 2 is used. However, the unit circuit P2 of FIG. 6 may be used instead of the unit circuit P1.
As shown in FIG. 6, each unit circuit P2 includes a light emitting element 8, a capacitive element C12, a first transistor Tr12, and a second transistor Tr22.

  The capacitive element C12 is means for holding the data potential VD [j] supplied from the signal line 6. As shown in FIG. 6, the capacitive element C12 includes a first electrode E1 connected to the third control line 3B and a second electrode E2 connected to the first transistor Tr12.

  The first transistor Tr12 is a switching element that conducts when the second control line 3C is selected, thereby conducting the second electrode E2 of the capacitive element C12 and the signal line 6. As shown in FIG. 6, one of the source and the drain of the first transistor Tr12 is connected to the second electrode E2 of the capacitor C12, and the other of the source and the drain is connected to the signal line 6.

  The gate of the first transistor Tr12 is connected to the second control line 3C. Accordingly, when the second control signal GC [i] transitions to the active state, the first transistor Tr12 belonging to the i-th row is turned on, and the second electrode E2 and the signal line 6 are electrically connected, while the second When the control signal GC [i] transitions to the inactive state, the first transistor Tr12 belonging to the i-th row is turned off, and the second electrode E2 and the signal line 6 are turned off.

  The second transistor Tr22 is a switching element that conducts when the first control line 3W is selected, thereby conducting the second electrode E2 of the capacitive element C12 and the light emitting element 8. As described above, since one of the source and the drain of the first transistor Tr12 is connected to the second electrode E2 of the capacitor C12, the second transistor Tr22 emits light from one of the source and the drain of the first transistor Tr12. It can also be considered as a switching element that conducts the element 8. As shown in FIG. 6, one of the source and the drain of the second transistor Tr22 is connected to the anode of the light emitting element 8, and the other of the source and the drain is connected to the second electrode E2 of the capacitive element C12.

  The gate of the second transistor Tr22 is connected to the first control line 3W. Accordingly, when the first control signal GW [i] transitions to the active state, the second transistor Tr22 belonging to the i-th row is turned on, and the second electrode E2 of the capacitive element C12 and the light-emitting element 8 are brought into conduction. On the other hand, when the first control signal GW [i] transitions to the inactive state, the second transistor Tr22 is turned off, and the second electrode E2 of the capacitive element C12 and the light emitting element 8 are brought out of conduction.

  2 and 6, all of the first transistor Tr1 and the second transistor Tr2, and the first transistor Tr12 and the second transistor Tr22 may be N-channel type, or all may be P-channel type. However, they may be composed of different channel type transistors.

<Application example>
Next, an electronic apparatus to which the light emitting device 10 according to the first embodiment is applied will be described.

  FIG. 7 is a perspective view showing a configuration of a mobile personal computer using the light emitting device 10 according to the first embodiment as an image display device. The personal computer 2000 includes a light emitting device 10 as a display device and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002.

  FIG. 8 shows a mobile phone to which the light emitting device 10 according to the first embodiment is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and the light emitting device 10 as a display device. By operating the scroll button 3002, the screen displayed on the light emitting device 10 is scrolled.

  FIG. 9 shows an information portable terminal (PDA: Personal Digital Assistant) to which the light emitting device 10 according to the first embodiment is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and the light emitting device 10 as a display device. When the power switch 4002 is operated, various types of information such as an address book and a schedule book are displayed on the light emitting device 10.

  Electronic devices to which the light emitting device 10 according to the first embodiment is applied include those shown in FIGS. 7 to 9, digital still cameras, televisions, video cameras, car navigation devices, pagers, electronic notebooks, and electronic papers. , Calculators, word processors, workstations, video phones, POS terminals, video players, devices with touch panels, and the like.

  DESCRIPTION OF SYMBOLS 10 ... Light-emitting device, P1, P2 ... Unit circuit, 8 ... Light-emitting element, C1 ... Capacitor element, E1 ... 1st electrode, E2 ... 2nd electrode, Tr1, Tr12 ... 1st transistor, Tr2, Tr22 ... 2nd transistor, DESCRIPTION OF SYMBOLS 100 ... Pixel array part, 200 ... Scanning side drive circuit, 210 ... 1st shift transfer circuit, 220 ... 1st output circuit, 230 ... 2nd shift transfer circuit, 240 ... 2nd output circuit, 250 ... 3rd output circuit, 260 ... Control circuit, 270 ... Selector, VL ... First potential, L1 ... Low potential line, VH ... Second potential, L2 ... High potential line, 300 ... Data side drive circuit, SSW [1] to SSW [n] ... Sampling switch, GS [1] to GW [n] ... fourth control signal, VD [1] to VD [n] ... data potential, 400 ... processing circuit, 3 ... scanning line, 3W ... first control line, 3C ... 2nd control line, 3B ... 3rd Control line, GW [1] to GW [m] ... first control signal, GC [1] to GC [m] ... second control signal, GB [1] to GB [m] ... third control signal, 6 ... Signal line, Pw: writing period, Ps: potential shift period, Pd: driving period.

Claims (8)

A plurality of scanning lines, a plurality of signal lines, a plurality of unit circuits provided corresponding to intersections of the plurality of scanning lines and the plurality of signal lines, and a first signal among the plurality of signal lines A first switching element connected between the line and the data side driving circuit,
Each of the plurality of unit circuits is
A light emitting element;
A capacitive element having a first electrode and a second electrode;
A second switching element connected between the first signal line and the light emitting element;
A third switching element connected between the first signal line and the second electrode;
A method of driving a light emitting device having
In a first period, a predetermined third switching element among the third switching elements belonging to the plurality of unit circuits is turned on, the first switching element is turned on, and the data side driving circuit Supplying a data potential to the first signal line;
In the second period after the first period, after the first switching element and the second switching element are turned off, the potential of the first electrode of the capacitor element is shifted,
A driving method of a light-emitting device, wherein the signal line is connected to the light-emitting element through the second switching element in a third period after the second period. The light emitting element has an anode and a cathode,
The anode is connected to the second switching element;
The transition from the state in which the first potential is supplied to the first electrode of the capacitive element to the state in which the second potential higher than the first potential is supplied in the second period. Driving method of light emitting device. The light emitting element has an anode and a cathode,
The cathode is connected to the second switching element;
The transition from the state in which the first potential is supplied to the first electrode of the capacitive element to the state in which the second potential lower than the first potential is supplied in the second period. Driving method of light emitting device. In a fourth period after the third period, a transition is made from a state in which the second potential is supplied to the first electrode of the capacitive element to a state in which the first potential is supplied,
The driving method of the light-emitting device according to claim 2, wherein the second switching element is turned on before and after the transition. A plurality of scanning lines, a plurality of signal lines, a plurality of unit circuits provided corresponding to intersections of the plurality of scanning lines and the plurality of signal lines, and a scanning side connected to the plurality of scanning lines A drive circuit, and a data side circuit connected to the plurality of signal lines,
The data side circuit is:
A data side drive circuit;
A first switching element connected between the data side driving circuit and a first signal line among the plurality of signal lines;
Each of the plurality of unit circuits is
A light emitting element;
A capacitive element having a first electrode and a second electrode;
A second switching element connected between the first signal line and the light emitting element;
A third switching element connected between the first signal line and the second electrode;
Have
Each of the plurality of scanning lines supplies a first control line for supplying a first control signal for controlling the third switching element, and a second control for supplying a second control signal for controlling the second switching element. A third control line connected to the first electrode and supplying a third control signal;
With
The scanning-side control circuit is a light-emitting device that generates the third control signal as a signal in association with the second control signal.   The light-emitting device according to claim 5, wherein the scanning-side control circuit generates the third control signal so as to have a number of pulses corresponding to a pulse width of the second control signal. The scanning side control circuit includes a shift transfer circuit,
The light emitting device according to claim 5, wherein the second control signal and the third control signal are generated or controlled based on an output of a shift transfer circuit.   An electronic apparatus comprising the light emitting device according to claim 5.

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