JP2007256733A - Electro-optical device, driving method thereof, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve effectiveness of a measurement result by allowing measurement after completion of an electro-optical device. <P>SOLUTION: In a first mode, a measurement signal F supplied from an input/output terminal T2 is supplied to a gate of a driving transistor NH1 through a data line 14(G), and a measurement signal F supplied from an input/output terminal T4 is supplied to a source of the driving transistor NH1 through a data line 14(B) adjacent to the data line 14(G). Meanwhile, a source voltage h of the driving transistor NH1 is outputted as a measurement object signal through a potential line 17(G). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an electro-optical device including an electro-optical element such as an OLED (Organic Light Emitting Diode) element, a method of driving this type of electro-optical device, and an electronic apparatus including the electro-optical device.

The electro-optical device includes a plurality of pixels arranged on a substrate corresponding to each intersection of a plurality of scanning lines and a plurality of data lines, and the pixel level is determined according to a data signal supplied to each data line. Key is controlled. Various circuits are conceivable for the pixel, but one having an OLED element as an electro-optical element and a transistor for supplying a driving current to the OLED element is known. In such a pixel, the luminance of each pixel becomes non-uniform due to variations in transistor characteristics (for example, threshold voltage) and OLED element characteristics.
In order to solve this problem, Patent Document 1 discloses in advance the measurement of the electrical characteristics of the transistors constituting the pixel, and the correction data according to the measurement results and the deterioration prediction data for predicting the deterioration of the OLED element before shipping the product. A technique of storing and correcting using correction data and deterioration prediction data is disclosed.
JP 2004-145257 A (paragraph number 0024)

However, in the technique disclosed in Patent Document 1, since correction data is stored before the product is shipped, it can be corrected even if the electrical characteristics of the transistor change after the product has passed to the end user. could not. In addition, since the deterioration of the OLED element is only a prediction, accurate correction is difficult.
In addition, in order to measure the characteristics of a transistor or an OLED element, it is necessary to provide a measurement wiring separately from the wiring used for display.
The present invention has been made in view of such circumstances, and an object of the present invention is to improve the effectiveness of measurement results by enabling measurement after completion of the electro-optical device.

In order to solve this problem, an electro-optical device according to the present invention includes a plurality of data lines each having a pixel connected thereto, and a plurality of data lines corresponding to each of the plurality of data lines. An input / output terminal, a signal generation unit (for example, the data line driving circuit 24 of the embodiment) that generates a data signal corresponding to the gradation specified for each pixel for each data line, and the data signal before the driving mode. Supplying to the corresponding data line via the entry output terminal, via the data line corresponding to the pixel to be measured in the measurement mode and the input / output terminal corresponding to the data line adjacent to the data line, Input / output of measurement signals for measuring characteristics of pixel components (for example, drive transistor NH1 and OLED element 11 of the embodiment) and signals under measurement indicating measurement results of the components. Output section for performing (e.g., the transistor Tr embodiment)
And the pixel captures the data signal supplied via the corresponding data line in the drive mode, and the measurement signal via the corresponding data line and the data line adjacent to the data line in the measurement mode. And a selection section (for example, the transistors N2 to N4, NT1, and NT2 in the embodiment) that output the signal under measurement.

According to the present invention, the measurement signal and the signal under measurement are transmitted using the data line of the adjacent pixel in addition to the data line corresponding to the pixel to be measured. That is, since the adjacent data lines are also used for measurement, it is not necessary to provide special wiring for measurement, or the number of measurement wirings can be reduced. Further, since the measurement signal and the signal under measurement are input / output via the input / output terminal for inputting the data signal in the drive mode, it is not necessary to newly provide an input / output terminal. In addition, since the measurement of the constituent elements can be performed using the driving input / output terminal, the measurement can be performed after the electro-optical device is completed.

In the electro-optical device described above, a plurality of potential lines paired with each of the plurality of data lines, a reference potential line to which a reference potential is supplied, and the plurality of data lines and the plurality of input lines in the driving mode. And connecting the reference potential line and the plurality of potential lines, and selectively selecting the plurality of data lines, the plurality of potential lines, and the plurality of input / output terminals in the measurement mode. A signal switching unit connected to the input / output unit, and the input / output unit uses the signal switching unit to connect a data line and a potential line corresponding to a pixel to be measured in the measurement mode,
The measurement signal and the signal under measurement are preferably input / output via the data line adjacent to the data line and the input / output terminal connected to the potential line adjacent to the potential line.
According to the present invention, a measurement signal and a signal under measurement can be transmitted using a pair of a data line and a potential line and a pair of a data line and a potential line adjacent thereto, so that the number of signals to be transmitted is increased. Therefore, it becomes possible to obtain the characteristics of the constituent elements in detail.

More specifically, in the measurement mode, the characteristics of the constituent elements are measured every N (N is a natural number of 2 or more) pixels, the measurement target pixels are shifted, and the measurement is repeated N times. The entry output unit preferably changes the input / output terminal for inputting / outputting the measurement signal and the signal under measurement in accordance with the change of the pixel to be measured. Since the number of input / output terminals is limited,
If the number of measurement signals and signals to be measured is large, it may be possible to increase the number of input / output terminals for measurement. However, according to the present invention, characteristics are measured in N times, so the number of input / output terminals is increased. The characteristics of the component can be measured without any problems. Of course, the characteristics of a plurality of pixels may be measured by one measurement out of N measurements. For example, when a pixel corresponds to a plurality of display colors, the measurement may be performed for each display color. In this case, measurement is simultaneously performed for pixels having the same display color. Therefore, the measurement time can be shortened as compared with the case where measurement is performed for each pixel.

Here, the pixel includes a transistor that outputs a driving current according to the data signal, and an electro-optical element that emits light with a luminance according to the driving current, and a component to be measured is the transistor. Preferably, the measurement signal gives a gate potential of the transistor, and the signal under measurement is at least one of a source potential and a drain potential of the transistor. In this case, the electrical characteristics of the driving transistor can be measured.

The pixel includes a transistor that outputs a driving current according to the data signal, and an electro-optical element that emits light with a luminance according to the driving current, and a component to be measured is the electro-optical element. The measurement signal may be a voltage applied to the electro-optic element, and the signal under measurement may be a current flowing through the electro-optic element. In this case, the characteristics of the electro-optical element can be measured.

In the electro-optical device described above, a storage unit that stores correction data generated so that the luminance between the pixels approaches uniformly based on the signal under measurement obtained in the measurement mode, and the read out from the storage unit A correction unit that corrects gradation data indicating the gradation of the pixel using correction data to generate corrected gradation data, and the signal generation unit includes the data based on the corrected gradation data. Preferably, a signal is generated. According to the present invention, since the gradation data is corrected based on the correction data generated based on the measurement result, it is possible to reduce the luminance variation between the pixels.

Here, the correction data indicates a first coefficient corresponding to a threshold voltage of the transistor and a second coefficient corresponding to a current amplification factor of the transistor, and the correction unit includes the first coefficient. Preferably, the gradation data is added to the gradation data, and the gradation data is multiplied based on the second coefficient to generate the corrected gradation data. According to the present invention, correction is performed by addition and multiplication. Of course, the addition process includes not only the case of adding a positive value but also the case of adding a negative value. In this sense, the addition process substantially functions as a subtraction process.

The electro-optical device described above designates the drive mode and the measurement mode, assigns the drive mode to a part of a vertical scanning period, and assigns the measurement mode to the remaining period of the vertical scanning period. It is preferable to provide a control unit. According to the present invention, since the state of the constituent elements of the pixel is measured and corrected during the period in which the image is displayed, the image can be displayed with accurate luminance. Although the pixel temperature differs immediately after the power is turned on and after a lapse of a certain time, according to the present invention, correction can be performed following a short-term temperature change, and further, long-term It is also possible to perform a correction following the change.

Next, an electronic apparatus according to the present invention includes the above-described electro-optical device, and includes, for example, a display device such as a light emitting device and a liquid crystal device, a personal computer, a mobile phone, a digital still camera, and a video camera. To do. In addition, for example, it can be used as a line head in an optical writing type image forming apparatus (for example, a printer).

Next, the driving method of the electro-optical device according to the invention includes a plurality of pixels connected to each of the plurality of data lines and a plurality of input / output terminals provided corresponding to each of the plurality of data lines. A method of driving an electro-optical device provided, wherein in a driving mode, a data signal corresponding to a specified gradation for each pixel is generated for each data line, and the data signal is handled via the input / output terminal. The data signal supplied to the data line, the data signal supplied via the data line is taken into each pixel, and in the measurement mode, the data line corresponding to the pixel to be measured and the data line adjacent to the data line The measurement signal for measuring the characteristics of the component of the pixel and the signal under measurement indicating the measurement result of the component are input / output via the input / output terminal corresponding to Via a data line adjacent to the data line and the corresponding data lines to respond and outputs the signal to be measured with capturing the measurement signal.

According to the present invention, the measurement signal and the signal under measurement are transmitted using the data line of the adjacent pixel in addition to the data line corresponding to the pixel to be measured. That is, since the adjacent data lines are also used for measurement, it is not necessary to provide special wiring for measurement, or the number of measurement wirings can be reduced. Further, since the measurement signal and the signal under measurement are input / output via the input / output terminal for inputting the data signal in the drive mode, it is not necessary to newly provide an input / output terminal. In addition, since the measurement of the constituent elements can be performed using the driving input / output terminal, the measurement can be performed after the electro-optical device is completed.

In the electro-optical device driving method described above, the electro-optical device includes a plurality of potential lines paired with each of the plurality of data lines, and a reference potential line to which a reference potential is supplied. Connecting the plurality of data lines and the plurality of input / output terminals, connecting the reference potential line and the plurality of potential lines, and in the measurement mode, the plurality of data lines and the plurality of potential lines. And the plurality of input / output terminals are selectively connected, and are connected to a data line and a potential line corresponding to a pixel to be measured, and a data line adjacent to the data line and a potential line adjacent to the potential line. Preferably, the measurement signal and the signal under measurement are input / output via the input / output terminal. According to the present invention, a measurement signal and a signal under measurement can be transmitted using a pair of a data line and a potential line and a pair of a data line and a potential line adjacent thereto, so that the number of signals to be transmitted is increased. Therefore, it becomes possible to obtain the characteristics of the constituent elements in detail.

Here, the correction data generated so that the luminance between the pixels approaches uniformly based on the signal under measurement obtained in the measurement mode is stored, and the gradation of the pixel is adjusted using the stored correction data. It is preferable that corrected gradation data is generated to generate corrected gradation data, and the data signal is generated based on the corrected gradation data. According to the present invention, since the characteristics of the constituent elements are measured and correction is performed based on the measurement results, the difference in luminance between pixels can be reduced.

In the above-described invention, the electro-optical element is an element whose optical characteristics change depending on electric energy, and includes, for example, a liquid crystal element in addition to a light-emitting element such as an organic light-emitting diode or an inorganic light-emitting diode.

<A: Embodiment>
FIG. 1 is a block diagram showing a configuration of an electro-optical device 1 according to an embodiment of the present invention. The electro-optical device 1 operates in a drive mode for displaying an image and a measurement mode for measuring the electrical characteristics of the drive transistor NH1 and the OLED element 11 (see FIG. 2) as components of the pixel circuit P. As shown in FIG. 1, the electro-optical device 1 includes an electro-optical panel 10 and a scanning line driving circuit 22.
A data line driving circuit 24, a voltage generating circuit 27, a control circuit 29, a correction circuit 30, and a memory 40.

In the pixel region A of the electro-optical panel 10, m (m is a natural number) extending in the X direction (row direction).
A scanning line 12 is formed. Although omitted in FIG. 1, 5 is parallel to the scanning line 12.
A control line of books is formed. In the pixel region A, n data lines 14 extending in the Y direction (column direction) orthogonal to the X direction and potential lines 17 paired with the data lines 14 are formed (
n is a natural number). A pixel circuit P is arranged corresponding to each intersection of the scanning line 12 and the data line 14. Therefore, these pixel circuits P are arranged in a matrix in the X direction and the Y direction in the pixel region A. Each pixel circuit P is an OLE which is a current driven self-luminous element.
D element 11 is included. Note that “R”, “G”, and “B” shown in the drawing represent display colors of the pixel circuits P. In this case, the emission color of the OLED element 11 may correspond to “R”, “G”, and “B”, or the emission color of the OLED element 11 may be white and the display color may be obtained by a color filter.

Further, n input / output terminals T <b> 1 to Tn corresponding to the n data lines 14 are provided at the end of the electro-optical panel 10. Further, a switching circuit 25 is formed between the plurality of input / output terminals T1 to Tn, the plurality of data lines 14, and the plurality of potential lines 17. Switching circuit 25
Includes reference potential lines Lr, Lb, and Lg for supplying an R reference potential REF-R, a G reference potential REF-G, and a B reference potential REF-B. In the drive mode, the switching circuit 25 connects the plurality of data lines 14 and the plurality of input / output terminals T1 to Tn, and the reference potential lines Lr, Lb,
Lg and the plurality of potential lines 14 are connected, and the plurality of data lines 14 and the plurality of potential lines 17 and the plurality of input / output terminals T1 to Tn are selectively connected in the measurement mode.

The scanning line driving circuit 22 and the data line driving circuit 24 are IC chips, and the electro-optical panel 1
It is mounted outside 0 (for example, on a wiring board mounted on the electro-optical panel 10). Note that the scanning line driving circuit 22 and the data line driving circuit 24 are formed by COG (Chip On Glass) technology.
At least one of the above may be mounted on the electro-optical panel 10. The scanning line driving circuit 22 sequentially selects each of the m scanning lines 12 and supplies a selection signal to each selection line. More specifically, the scanning line driving circuit 22 sends scanning signals EW-1, EW-2,..., EW-m that sequentially become active levels (H levels) to the scanning lines 12 for each horizontal scanning period. Output.
When the scanning signal EW-i (i is an integer satisfying 1 ≦ i ≦ m) becomes an active level, it means that the i-th row has been selected. Details of the selection signal will be described later.

On the other hand, the data line driving circuit 24 supplies the data signal D to each pixel circuit P connected to the scanning line 12 selected by the scanning line driving circuit 22 in the driving mode. Data signal Dj
(J is an integer satisfying 1 ≦ j ≦ n) is a voltage signal designating the luminance (gradation) of the pixel circuit P in the j-th column. In addition, the data line driving circuit 24 supplies the measurement signal F to the pixel circuit P in the measurement mode and obtains the signal under measurement M indicating the measurement result from the pixel circuit P. Note that the scanning line driving circuit 22 can be formed not only by an IC chip but also partially or entirely in a glass substrate.

The voltage generation circuit 27 generates the following voltages used in the electro-optical device 1. First, the power supply voltages VE-R, VE-G, and VE-B are voltages supplied to the R, G, and B color pixel circuits P, respectively, and are control signals supplied from the control circuit 29. To control whether or not to output. Although it is always output in the drive mode, in the measurement mode, the pixel circuit P to be measured is controlled for each color as described later, and only the corresponding power supply voltage is output. next,
The voltage generation circuit 27 includes an R reference potential REF-R, a G reference potential REF-G, and a B reference potential R.
EF-B is output. R reference potential REF-R, G reference potential REF-G, and B reference potential R
EF-B is a voltage that defines the source potential of the driving transistor.

The control circuit 29 supplies control signals to the scanning line driving circuit 22, the data line driving circuit 24, the switching circuit 25, and the voltage generation circuit 27 to control these circuits. The control circuit 29
Switch between drive mode and measurement mode. For example, the measurement mode may be assigned to part or all of the vertical blanking period. In this case, it is preferable to allocate at least one horizontal scanning period to the measurement mode from the viewpoint of securing the measurement time. By assigning the measurement mode in this way, it becomes possible to perform correction following the state of the drive transistor and OLED element that change from moment to moment, and display quality can be improved. Note that the measurement mode may be assigned to a period other than the vertical blanking period. In short, it is only necessary to perform characteristic measurement during a period that does not affect the display. For example, the control circuit 29 may specify the drive mode and the measurement mode, assign the drive mode to a part of the vertical scanning period, and assign the measurement mode to the remaining period of the vertical scanning period.

In the measurement mode, the correction circuit 30 supplies the measurement signal F to the data line driving circuit 24 and acquires the signal under measurement M from the data line driving circuit 24. Then, the correction circuit 30 generates correction data Dh based on the acquired signal under measurement M, and stores the generated correction data Dh in the memory 40. On the other hand, in the drive mode, the correction circuit 30 reads the correction data Dh from the memory 40 and supplies the corrected gradation data dh obtained by correcting the gradation data d based on the correction data Dh to the data line driving circuit 24. To do. For example, the correction data Dh includes first data H1 corresponding to the threshold voltage of the driving transistor and second data H2 corresponding to the current amplification factor of the driving transistor. The correction circuit 30 is composed of a linear driver, and generates corrected gradation data dh by executing a linear operation according to the following equation.
Dh = (H1, H2)
dh = H1 + H2 * Dh

The first data H1 and the second data H2 are obtained by measuring the current-voltage characteristics of the driving transistor, and are set so that the luminance between the pixels approaches uniform. The memory 40 in this example is volatile, but may be non-volatile. In addition, measurement of drive current and emission luminance is performed at the time of product shipment or immediately after power-on, and correction data obtained there and correction data obtained in real time are combined to correct gradation data d. Also good.

Next, the configuration of the pixel circuit P will be described with reference to FIG. In the drawing, only the pixel circuit P corresponding to the R color belonging to the i-th row is shown, but the other pixel circuits P have the same configuration. The pixel circuit P in the present embodiment is a voltage driving type (so-called voltage programming method) circuit in which the luminance (gradation) of the OLED element 11 is controlled in accordance with the voltage value of the data signal D. A so-called current programming method may be employed.

As shown in FIG. 2, the pixel circuit P includes an OLED element 11, a capacitive element CH1, a p-channel transistor P1, n-channel transistors N1 to N4, NT1 and NT2,
In addition, a drive transistor NH1 is provided. The drive current that flows into the OLED element 11 is determined by the gate-source voltage of the drive transistor NH1. A capacitive element CH1 is provided between the gate and source of the driving transistor NH1. The capacitive element CH1 is a means for holding the voltage written during the writing period in the drive mode. The first control line L1
Control signal XEP-i via the second control line L2, control signal ETB-i via the third control line L3, control signal ETG-i via the third control line L4, control signal via the fourth control line L4 ETR-i is supplied with the control signal EN-i from the scanning line driving circuit 22 via the fifth control line L5.

A power supply voltage VEL-R is supplied to the source of the transistor P1, a control signal XEP-i is supplied to its gate, and its drain is connected to the drain of the driving transistor NH1. When the control signal XEP-i becomes low level (active), the transistor P1 is turned on, and the power supply voltage VEL-R is supplied to the drive transistor NH1.

A transistor N2 is provided between the gate of the driving transistor NH1 and the data line. A scanning signal EW-i is supplied to the gate of the transistor N2 through the scanning line 12. When the scanning signal EW-i becomes high level, the data signal Dj supplied via the data line 14 is applied to one terminal of the capacitive element CH1. Transistors N3 and N4 are provided between the source of the driving transistor NH1 and the potential line 17. A power supply voltage VEL-R is supplied to the gate of the transistor N4. Since the power supply voltage VEL-R is always high in the drive mode, the transistor N4 is always on in the drive mode. On the other hand, the scanning signal EW-i is supplied to the gate of the transistor N3. Accordingly, when the i-th scanning line 12 is selected, the transistor N3 is turned on, and the R reference potential REF-R is supplied to the other terminal of the capacitive element CH1. Thereafter, the scanning signal EW−
Even if i changes to a low level, a voltage corresponding to the gradation to be displayed is held between the terminals of the capacitive element CH1.

Between the source of the driving transistor NH1 and the anode of the OLED element 11, the transistor N
1 is provided, and a control signal EN-i is supplied to its gate. Control signal EN-i
Becomes a high level during the light emission period of the drive mode, and the drive current is OLED element 11 during the period.
To be supplied.

Further, a transistor NT1 is provided between the source of the driving transistor NH1 and the data line 14 of the pixel circuit adjacent to the pixel circuit P, and the anode of the OLED element 11 and the pixel circuit adjacent to the pixel circuit P are provided. Between the potential line 17, a transistor NT2 is provided. The gates of the transistors NT1 and NT2 are connected to the fourth control line L4. G
In the color pixel circuit P, those gates are connected to the third control line L3, and in the B color pixel circuit P, those gates are connected to the second control line L2.

FIG. 3 is a timing chart for explaining the operation of the pixel circuit P in the drive mode, FIG. 4 shows the state of the pixel circuit P in the writing period, and FIG. 5 shows the state of the pixel circuit P in the light emission period. . As shown in FIG. 3, the scanning signals EW-1, EW-2,... Sequentially become high level every horizontal scanning period 1H. A period during which each scanning signal EW is at a high level is a writing period Twrt. In the writing period Twrt, the control signal XEP-1 becomes high level so that the transistor P1 is turned off, the scanning signal EW-1 becomes high level, so that the transistors N2 and N3 are turned on, and the control signal EN-1 is low level. Therefore, transistor N1
Is off, and the control signal ETR-1 is at low level, so transistors NT1 and NT2
Is turned off. As a result, the data signal D1 is supplied to the gate of the drive transistor NH1, while the R reference potential REF-R is supplied to the source of the drive transistor NH1, and the potential difference is held by the capacitive element CH1.

Further, in the light emission period Tel, the control signal XEP-1 is at a low level, so that the transistor P1 is turned on, and the scanning signal EW-1 is at a low level, so that the transistors N2 and N2
3 is off, and the control signal EN-1 is at high level, so the transistor N1 is on,
Since the control signal ETR-1 is at a low level, the transistors NT1 and NT2 are turned off. As a result, the gate and source of the driving transistor NH1 are separated from the data line 14 and the potential line 17. At this time, the power supply voltage VEL-R is applied to the drain of the drive transistor NH1 via the transistor P1, and the drive current Iel is applied to the O1 via the transistor N1.
It flows into the LED element 11. The magnitude of the drive current Iel is determined according to the gate-source voltage of the drive transistor NH1, the data signal D1 is generated based on the corrected gradation data dh, and the R reference potential REF-R is fixed. . Therefore, the drive current Iel is in accordance with the gradation to be displayed. As a result, the OLED element 11 can emit light with a desired luminance.

FIG. 6 shows the details of the switching circuit 25 and the configuration of its peripheral circuits. The switching circuit 25 includes a switch group SWR for R color, a switch group SWG for G color, and a switch group SWB for B color.
Each switch group includes five switches Sr1 to Sr5, Sg1 to Sg5, and Sg1 to Sg5. These switches are turned on when the control signal supplied to the control terminal is at a high level, and turned off when the control signal is at a low level. Further, the switching circuit 25 has an R reference potential REF−.
A reference potential line Lr to which R is supplied, a reference potential line Lb to which a B reference potential REF-B is supplied, and a reference potential line Lg to which a G reference potential REF-G is supplied. L
g and Lb are connected to switches Sr3, Sg3, and Sb3, respectively.

In the drive mode described above, the control signals VG-R, VG-G, and VG-B, and VRE-R, VRE-G, and VRE-G are at a high level, and the other control signals are at a low level. Therefore, the switches Sr1, Sg1, and Sb1, and Sr3, Sg3,
And Sb3 are turned on, and the other switches are turned off. That is, the switching circuit 25
Functions as means for connecting the plurality of data lines 14 and the plurality of input / output terminals T1 to Tn and connecting the reference potential lines Lr, Lg, and Lb and the plurality of potential lines 17 in the drive mode. .

FIG. 7 shows a truth table of various control signals in the measurement mode. In this example, the measurement mode is
A first mode for measuring the characteristics of the drive transistor NH1 and a second mode for measuring the characteristics of the OLED element 11 are included. Further, in the first mode and the second mode, the pixel circuit P to be measured is specified as follows. First, measurements are taken on a line by line basis. In this example, measurement is performed in the order of the first row, the second row,. Second, in the measurement for each row, not all the pixel circuits P belonging to the row are measured at the same time, but the R pixel circuit P, the G pixel circuit P,
Measurement is performed in the order of the B-color pixel circuit P. In other words, measurement is performed every three pixel circuits P, and the measurement is repeated three times by shifting the pixel circuit to be measured. In this example, the measurement is performed three times, but more generally, measurement is performed every N (N is a natural number of 2 or more) pixel circuits P, and the pixel circuit P to be measured is shifted. The measurement may be repeated N times.

FIG. 8 shows an operation when the pixel circuit P to be measured in the first mode is G color. Since the control signal XEP-i is at the low level, the control signal ETG-i is at the high level, and the scanning signal EW-i is at the high level as shown by the thick frame in FIG. 7, the transistor P1 is shown in FIG.
, N2, and N3 are turned on, and the transistor N1 is turned off. Further, since the power supply voltage VEL-G is turned on (high level) and VEL-R and VEL-B are turned off (low level), the transistor N4 of the G color pixel circuit P is turned on, while the R color and The transistor N4 of the B-color pixel circuit P is turned off. In addition, since the control signal ETG-i becomes high level, the transistors NT1 and NT2 of the G-color pixel circuit P are turned on.
On the other hand, since the control signals ETR-i and ETB-i are at a low level, the transistors NT1 and NT2 of the R and B pixel circuits P are turned off.

Next, the control signals VG-G, VM-G, and VFIM-G supplied to the switching circuit 25 are at a high level, and the other control signals are at a low level. Accordingly, as shown in FIG. 8, the switches Sg1 and Sg4 of the switch group SWG are turned on, and the switch Sb5 of the switch group SWB is turned on.
At this time, the gate voltage VGIN becomes the measurement signal F as input / output terminal T2 → switch Sg.
It is applied through the path of the gate of the data line 14 (G) corresponding to the 1 → G color pixel circuit → the transistor N2 → the driving transistor NH1. The source voltage VSIN is applied as the measurement signal F through the source path of the input / output terminal T4 → the switch Sb5 → the data line 14 (B) corresponding to the B color pixel circuit → the transistor NT1 → the drive transistor NH1. Further, the source voltage VS of the drive transistor NH1 is the signal under measurement M, and the potential line 17 (corresponding to the source of the drive transistor NH1, the transistor N4, the transistor N3, and the G pixel circuit)
G) The switch Sg4 is taken out along the path of the input / output terminal T3.

FIG. 10A shows a simplified circuit for measuring characteristics of the driving transistor NH1. As shown in this figure, the measurement signal F (VGIN, VSIN) is supplied through the input / output terminals T2 and T4, and the signal under measurement M (VS) is output through the input / output terminal T3. Input / output terminal T4
An ammeter is provided in this path, and current is measured. Thereby, the voltage-current characteristic of the driving transistor NH1 is measured.

In the drive mode, the G color data signal is sent from the input / output terminal T2 shown in FIG.
In addition to outputting toward 4 (G), the G reference potential REF-G was output toward the potential line 17 (G). On the other hand, in the first mode, when measuring the characteristics of the driving transistor NH1 of the G pixel circuit, in addition to the data line 14 (G) and the potential line 17 (G), the data line 14 (
The measurement signal F and the signal under measurement M were input and output using the data line 14 (B) adjacent to G). By combining the measurement wiring and the driving wiring, the number of wirings can be reduced.
In addition, by performing measurement for each display color, signals can be input and output using input / output terminals (for example, T3 and T4) for other display colors during measurement of a certain display color (for example, G color). it can. As a result, there is no need to provide a measurement input / output terminal separately from the drive. Furthermore, since the pixel circuits having the same display color are measured in parallel, the measurement time can be shortened.

FIG. 9 shows an operation when the pixel circuit P to be measured in the second mode is G color. Since the control signal EN-i is at a high level as shown by a thick frame in FIG. 7, the transistor N1 is turned on and the transistors P1, N2, and N3 are turned off as shown in FIG.
Further, the power supply voltage VEL-G is on (high level), and VEL-R and VEL-B are off (
Low level), the transistor N4 of the G pixel circuit P is turned on,
The transistor N4 of the R and B pixel circuits P is turned off. In addition, control signal E
Since TG-i becomes high level, the transistors NT1 and NT2 of the G-color pixel circuit P are turned on. On the other hand, since the control signals ETR-i and ETB-i are at a low level, R
The transistors NT1 and NT2 of the color and B color pixel circuits P are turned off.

Next, the control signals VMOL-G and VFIM-G supplied to the switching circuit 25 are at a high level, and the other control signals are at a low level. Therefore, as shown in FIG.
The switches Sb2 and Sb5 of the WB are turned on.
At this time, the applied voltage VF becomes the measurement signal F as input / output terminal T4 → switch Sb5 → B.
Data line 14 (B) corresponding to the color pixel circuit → transistor NT1 → transistor N1 →
It is applied through the anode path of the OLED element 11. Further, the voltage VM of the anode of the OLED element 11
Is taken out as a signal under measurement M through the path of the anode of the OLED element 11 → the transistor NT2 → the potential line 17 (B) corresponding to the B color pixel circuit → the switch Sb2 → the input / output terminal T3.

FIG. 10B shows a simplified circuit for measuring characteristics of the OLED element 11. As shown in this figure, the measurement signal F (VF) is supplied through the input / output terminal T4, and the signal under measurement M (VM) is output through the input / output terminal T3. In addition, an ammeter is provided in the path of the input / output terminal T4, and current is measured. Thereby, the voltage-current characteristic of the OLED element 11 is measured.

In the second mode, when the characteristics of the OLED element 11 of the G color pixel circuit are measured, the measurement signal F and the signal under measurement M are input and output using the data line 14 (B) and the potential line 17 (B). The number of wirings can be reduced by using both the measurement wiring and the driving wiring. 2
The measurement signal F and the signal under measurement M were input / output using the input / output terminals T3 and T4. As a result, there is no need to provide a measurement input / output terminal separately from the drive. Furthermore, since the pixel circuits having the same display color are measured in parallel, the measurement time can be shortened.
As described above, in the present embodiment, by using the data line 14 and the potential line 17 of the adjacent pixel circuit, the measurement signal (F) and the signal under measurement (M) are added without adding the input / output terminals T1 to Tn. Was transmitted. Therefore, it is not necessary to connect the measuring device to the measurement input / output terminal to execute signal transmission / reception, and the characteristic measurement can be performed using the input / output terminals T1 to Tn used in the drive mode. Therefore, even after the electro-optical device 1 is completed, it is possible to measure the characteristics of the driving transistor NH1 and the OLED element 11 and perform correction so that the luminance is uniform based on the measurement result.

<B: Modification>
Various modifications are made to the embodiment. Specific modifications are as follows. In addition, the structure which combined each following aspect suitably is also employ | adopted.

(1) In the second mode of the embodiment, the control signals ETR, ETG, and ETB are used to measure the characteristics of the OLED element 11 for each RGB color, and the transistors NT1 and NT2 are controlled. The number of input / output terminals required for input / output of the measurement signal M is “2”. For this reason, odd-numbered columns and even-numbered columns may be measured alternately. In this case, a control signal ET1 for selecting an odd-numbered column and a control signal ET2 for selecting an even-numbered column may be used. Specifically, as shown in FIG. 11, the control line La for supplying the control signal ET1 and the control signal ET2
It suffices if a control line Lb for supplying is provided. In this case, the number of control lines can be reduced, and the configuration of the control circuit 29 can be simplified.

(2) Further, the transistors NT1 and NT2 are turned on / off by the power supply voltages VEL-R, VE.
You may control by LG and VEL-B. For example, the pixel circuit P shown in FIG. 12 can be employed. In this case, the power supply voltage VEL is applied to the gates of the transistors NT1 and NT2.
-R is supplied, the transistor N depends on whether the power supply voltage VEL-R is valid or not.
T1 and NT2 can be controlled on / off.

(3) In the first mode of the embodiment, the source voltage VS of the drive transistor NH1 is output as the signal to be measured M. However, in addition to this, the drain voltage may be measured. For example, the pixel circuit P shown in FIG. 13 can be employed. In this case, a measurement wiring 18 is formed along the potential line 17, and a P-channel transistor P2 is provided between the wiring 18 and the drain of the driving transistor NH1. A control signal XETP-1 is supplied to the gate of the transistor P2 via the control line L6. By setting the control signal XETP-1 to the low level, the drain voltage of the drive transistor NH1 can be taken out as the signal to be measured M through the wiring 18. FIG. 14 is a schematic diagram illustrating a simplified pixel circuit P in the first mode. In this example, since there are four measurement signals F and signals under measurement M, four input / output terminals are used.
Here, for the row to be measured, the control signals XEP and XETP are set to low level,
The control signal EW is set to the high level to turn on the transistors P1, P2, and N2 to N4. For the other non-selected rows, the transistor P2 needs to be turned off, but the other transistors Also, the logic level of the control signal may be inverted to turn off the transistors P1 and N2 to N4. In this case, when a leak current flows through the wiring 18 in the transistor P2 in the non-selected row, the drive transistor NH to be measured
The measurement accuracy of the drain voltage of 1 is lowered. If the leakage current when the gate of the transistor P2 in the non-selected row is at a high level (off state) tends to increase as the drain-source voltage increases, the leakage current is reduced by decreasing the drain-source voltage. It is possible. One of the source and the drain of the transistor P2 is connected to the transistor P1 in the pixel, and the other is connected to the measured line 18. When the measured line 18 has a voltage close to a high level, the drain current of the transistor P2 may be set to a high level to reduce the leakage current in order to reduce the source-drain voltage of the transistor P2.
In this case, the control signal XEP supplied to the non-selected row is set to the low level so that the transistor P1
Can be turned on. However, when giving priority to the measurement accuracy of the gate-source voltage of the drive transistor NH1, it is preferable to set the control signal XEP to high level in order to reduce the leakage current of the drive transistor NH1 in the non-selected row. The logic level of the control signal XEP in the non-selected row may be appropriately determined according to the measurement accuracy requirement. In order to reduce the leakage current of each transistor, it is also effective to configure each transistor with a series transistor having a common gate, that is, a so-called dual gate transistor.
In short, not only the transistor P2, but also the transistors P2, NT1, NT2, N3, and N4 in the non-selected rows connected to the measurement line and the line to be measured not only turn the gate off, but also the source-drain By reducing the voltage between them, the leakage current can be reduced, and as a result, the measurement accuracy can be increased. Therefore, it is preferable to timely control other control signals of non-selected rows. That is, the control method for the non-selected rows may be changed depending on which measurement value is to be improved. Note that since one of the transistors N2 is connected only to the gate of the transistor NH1, no leakage depending on the voltage between the source and the drain occurs.

(4) In the embodiment, the characteristics of the drive transistor NH1 and the OLED element 11 are individually measured, but these may be measured simultaneously. FIG. 15 shows a simplified schematic diagram of the pixel circuit P in the simultaneous measurement. In this case, the transistor N1 is turned on and the driving transistor NH1 is turned on.
A driving current is supplied to the OLED element 11 from the above. Simultaneous measurement can reduce the measurement time. Note that simultaneous measurement and individual measurement may be mixed.

(5) Although the reference potential lines Lr, Lb, and Lg are provided in the switching circuit 25 in the embodiment, these are provided in the data line driving circuit 24 and input / output terminals corresponding to the data line 14 and the potential line 17 are provided. Also good. For example, as shown in FIG. 16, the data signal D and the R reference potential REF-R may be output from the input / output terminals Ta and Tb. The data line 14 and the potential line 17 are formed adjacent to each other.
Since the gate-source voltage of the drive transistor NH1 is determined by the difference between the potential of the data line 14 and the potential of the potential line 17, even if in-phase noise is superimposed on these, the noise component can be canceled as the difference. Therefore, the electro-optical device 1 that is resistant to noise can be provided.

(6) In each embodiment, an active matrix type electro-optical device including a transistor for driving the OLED element 11 is illustrated, but a passive matrix type electro-optical device in which the pixel circuit P does not have these switching elements. The present invention also applies to an apparatus.

(7) In each embodiment, the electro-optical device 1 using the OLED element 11 which is a current-driven self-luminous element is illustrated, but other current-driven electro-optical elements and voltage-driven electro-optical elements are used. The present invention is also applied to the electro-optical device used. For example, liquid crystal display devices, inorganic E
Display device using L element, field emission display (FED: Field Emission Display)
), Surface-conduction electron emission display (SED)
Display, ballistic electron emission display (BSD: Ballistic electron Surface emi)
The present invention is also applied to various electro-optical devices such as a display device using a light-emitting diode, a writing device of an optical writing printer or an electronic copying machine.

<C: Application example>
Next, an electronic apparatus to which the electro-optical device according to the invention is applied will be described. FIG. 17 is a perspective view illustrating a configuration of a mobile personal computer that employs the electro-optical device 1 according to the embodiment as a display device. The personal computer 2000 includes the electro-optical device 1 as a display device and a main body 2010. The main body 2010 includes a power switch 200.
1 and a keyboard 2002 are provided. Since the electro-optical device 1 uses the OLED element 11, it is possible to display an easy-to-see screen with a wide viewing angle.

FIG. 18 shows a configuration of a mobile phone to which the electro-optical device 1 according to the embodiment is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and the electro-optical device 1 as a display device. By operating the scroll button 3002, the screen displayed on the electro-optical device 1 is scrolled.

FIG. 19 shows a portable information terminal (PDA: Personal) to which the electro-optical device 1 according to the embodiment is applied.
Digital Assistants). The information portable terminal 4000 includes a plurality of operation buttons 40.
01, a power switch 4002, and the electro-optical device 1 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 electro-optical device 1.

Electronic devices to which the electro-optical device according to the present invention is applied include those shown in FIGS. 17 to 19, digital still cameras, televisions, video cameras, car navigation devices, pagers, electronic notebooks, electronic papers, Examples include calculators, word processors, workstations, videophones, POS terminals, printers, scanners, copiers, video players, devices equipped with touch panels, and the like.

1 is a block diagram illustrating a configuration of an electro-optical device according to an embodiment of the invention. FIG. It is a circuit diagram which shows the structure of a pixel circuit. 6 is a timing chart illustrating an operation of the electro-optical device in a driving mode. It is explanatory drawing which shows the state of the pixel circuit in the writing period. It is explanatory drawing which shows the state of the pixel circuit in the light emission period. It is a circuit diagram which shows the structure of a switching circuit and its peripheral circuit. It is a truth table of various control signals in the measurement mode. It is explanatory drawing which shows operation | movement when the pixel circuit used as the measuring object in 1st mode is G color. It is explanatory drawing which shows operation | movement when the pixel circuit used as the measuring object in 2nd mode is G color. It is explanatory drawing which simplifies and shows the pixel circuit in a measurement mode. It is a circuit diagram which shows the example of the pixel circuit which concerns on a modification. It is a circuit diagram which shows the example of the pixel circuit which concerns on a modification. It is a circuit diagram which shows the example of the pixel circuit which concerns on a modification. It is explanatory drawing which simplifies and shows the pixel circuit of the modification in 1st mode. It is explanatory drawing which simplifies and shows the pixel circuit of the modification in measurement mode. It is a block diagram for demonstrating the input-output terminal which concerns on a modification. It is a perspective view which shows the structure of the personal computer to which this invention is applied. It is a perspective view which shows the structure of the mobile telephone to which this invention is applied. It is a perspective view which shows the structure of the portable information terminal to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electro-optical apparatus, 11 ... OLED element, 14 ... Data line, 17 ... Potential line, 24 ... Data line drive circuit, 25 ... Switching circuit, P ... Pixel circuit, D ... Data signal, F ... Measurement signal, M ... Signal to be measured, Lr, Lg, Lb ... reference potential line, T1 to Tn ... input / output terminals, NH1 ... drive transistor, d ... gradation data, Dh ... correction data, dh ... corrected gradation data.

Claims (12)

An electro-optical device in which a pixel is connected to each of a plurality of data lines,
A plurality of input / output terminals provided corresponding to each of the plurality of data lines;
A signal generation unit that generates a data signal corresponding to the gradation specified for each pixel for each data line;
In the drive mode, the data signal is supplied to the corresponding data line via the input / output terminal, and in the measurement mode, the data line corresponding to the pixel to be measured and the data line adjacent to the data line are An input / output unit that inputs and outputs a measurement signal for measuring the characteristics of the constituent element of the pixel and a signal under measurement indicating the measurement result of the constituent element, via the entry output terminal;
The pixel captures the data signal supplied via the corresponding data line in the drive mode, and captures the measurement signal via the corresponding data line and the data line adjacent to the data line in the measurement mode. Together with a selection unit that outputs the signal under measurement,
An electro-optical device comprising the electro-optical device. A plurality of potential lines paired with each of the plurality of data lines;
A reference potential line to which a reference potential is supplied;
In the drive mode, the plurality of data lines and the plurality of input / output terminals are connected, and the reference potential line and the plurality of potential lines are connected. In the measurement mode, the plurality of data lines and the plurality of data lines are connected. A signal switching unit for selectively connecting a plurality of potential lines and the plurality of input / output terminals;
The input / output unit includes, by the signal switching unit, a data line and a potential line corresponding to a pixel to be measured in the measurement mode, a data line adjacent to the data line, and a potential line adjacent to the potential line. The measurement signal and the signal under measurement are input / output via the connected input / output terminal.
The electro-optical device according to claim 1. In the measurement mode, the characteristics of the constituent elements are measured every N pixels (N is a natural number of 2 or more), the measurement target pixels are shifted, and the measurement is repeated N times.
The input / output unit changes the input / output terminal for inputting / outputting the measurement signal and the signal under measurement in accordance with a change of a pixel to be measured.
The electro-optical device according to claim 1 or 2. The pixel is
A transistor that outputs a drive current according to the data signal;
An electro-optic element that emits light with a luminance according to the drive current,
The component to be measured is the transistor, the measurement signal gives a gate potential of the transistor, and the signal under measurement is at least one of a source potential and a drain potential of the transistor.
The electro-optical device according to claim 2. The pixel is
A transistor that outputs a drive current according to the data signal;
An electro-optic element that emits light with a luminance according to the drive current,
The component to be measured is the electro-optical element, the measurement signal is a voltage applied to the electro-optical element, and the signal under measurement is a current flowing through the electro-optical element.
The electro-optical device according to claim 2. A storage unit for storing correction data generated so that the luminance between the pixels approaches uniformly based on the signal under measurement obtained in the measurement mode;
A correction unit that generates corrected gradation data by correcting gradation data indicating the gradation of the pixel using the correction data read from the storage unit;
The signal generation unit generates the data signal based on the corrected gradation data;
The electro-optical device according to claim 1, wherein the electro-optical device is any one of the above. The correction data indicates a first coefficient corresponding to the threshold voltage of the transistor and a second coefficient corresponding to the current amplification factor of the transistor;
The correction unit adds the gradation data based on the first coefficient and multiplies the gradation data based on the second coefficient to generate the corrected gradation data. ,
The electro-optical device according to claim 6. A controller that designates the drive mode and the measurement mode, assigns the drive mode to a part of a vertical scanning period, and assigns the measurement mode to the remaining part of the vertical scanning period; The electro-optical device according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 1. An electro-optical device driving method comprising a plurality of pixels connected to each of a plurality of data lines and a plurality of input / output terminals provided corresponding to each of the plurality of data lines,
In drive mode,
A data signal corresponding to the gradation specified for each pixel is generated for each data line,
Supplying the data signal to the corresponding data line via the input / output terminal;
The data signal supplied via the data line is taken into each pixel,
In measurement mode,
The measurement signal for measuring the characteristics of the component of the pixel and the component of the component via the input / output terminal corresponding to the data line adjacent to the pixel to be measured and the data line adjacent to the data line. Input and output the signal under measurement indicating the measurement result,
Capturing the measurement signal through the data line corresponding to the pixel to be measured and the data line adjacent to the data line and outputting the signal under measurement;
A driving method for an electro-optical device. The electro-optical device includes a plurality of potential lines paired with each of the plurality of data lines, and a reference potential line to which a reference potential is supplied,
In the driving mode,
Connecting the plurality of data lines and the plurality of input / output terminals, and connecting the reference potential line and the plurality of potential lines;
In the measurement mode,
Selectively connecting the plurality of data lines and the plurality of potential lines and the plurality of input / output terminals;
The data signal and potential line corresponding to the pixel to be measured, the data line adjacent to the data line, and the input / output terminal connected to the potential line adjacent to the potential line, the measurement signal and the Input / output the signal under measurement,
The method of driving an electro-optical device according to claim 10. Storing correction data generated so that the luminance between the pixels approaches uniformly based on the signal under measurement obtained in the measurement mode;
Using the stored correction data, the gradation data indicating the gradation of the pixel is corrected to generate corrected gradation data,
Generating the data signal based on the corrected gradation data;
12. The method for driving an electro-optical device according to claim 10 or 11, wherein:

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