JP2009053382A - Image display apparatus and driving method thereof - Google Patents

Abstract

An image display apparatus capable of correcting a luminance unevenness caused by non-uniform characteristics of a driving active element by measuring a driving current of a light emitting element selected during image display and a driving method thereof.
A correction value calculating unit 153 is provided for each data line in a first scanning line of a scanning line group after a selection signal corresponding to a reference value writing period is output in the last scanning line of the scanning line group. In the period until the selection signal corresponding to the data writing period is output, the current value stored in the current memory 140 of the corresponding current line 23-1 to 23-m and the first scanning line of a certain scanning line group The corresponding current in the period from when the selection signal corresponding to the data writing period is output until the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the scanning line group A difference between the line and the current value stored in the current memory is calculated, and a correction value is calculated based on the calculated difference.
[Selection] Figure 1

Description

  The present invention relates to an image display apparatus and a driving method thereof, and more particularly to an image display apparatus using a current-driven light emitting element and a driving method thereof.

  As an image display device using a current-driven light emitting element, an image display device (organic EL display) using an organic EL element (OLED: Organic Light Emitting Diode) is known. Since this organic EL display has the advantages of good viewing angle characteristics and low power consumption, it has attracted attention as a next-generation FPD (Flat Pan Display) candidate.

  In an organic EL display, usually, organic EL elements constituting pixels are arranged in a matrix. An organic EL element is provided at the intersection of a plurality of row electrodes (scanning lines) and a plurality of column electrodes (data lines), and a voltage corresponding to a data signal is applied between the selected row electrodes and the plurality of column electrodes. A device for driving an organic EL element is called a passive matrix type organic EL display. In addition, a thin film transistor (TFT) is provided at the intersection of a plurality of scanning lines and a plurality of data lines, a gate of a driving transistor is connected to the TFT, and the TET is turned on through the selected scanning line to thereby turn on the data line. A data signal is input to the gate of a driving transistor and an organic EL element is driven by the driving transistor is called an active matrix organic EL display.

  Unlike a passive matrix type organic EL display in which an organic EL element connected to each row electrode (scanning line) emits light only during a period in which each row electrode (scanning line) is selected, the active matrix type organic EL display performs the next scanning (selection). Since the organic EL element can emit light as much as possible, the brightness of the display is not reduced even if the duty ratio is increased. Accordingly, since it can be driven at a low voltage, it is possible to reduce power consumption. However, in the active matrix organic EL display, due to variations in characteristics of the driving transistor, even if the same data signal is given, the current value flowing through the organic EL element is different in each pixel, resulting in uneven luminance. was there.

  In a conventional organic EL display, as a compensation method for luminance unevenness due to variation and deterioration of characteristics of driving transistors (hereinafter collectively referred to as non-uniform characteristics), compensation by a complicated pixel circuit, feedback compensation by a representative pixel, A typical example is feedback compensation based on the sum of currents flowing through all pixels.

  However, complicated pixel circuits reduce the yield. Further, the feedback by the representative pixel or the feedback by the sum of the currents flowing through all the pixels cannot compensate for the nonuniformity of the characteristics of the driving transistor for each pixel.

  For the above reasons, several methods have been proposed for detecting non-uniform characteristics of driving transistors for each pixel with a simple pixel circuit.

For example, in the electro-optical device disclosed in Patent Document 1, a step of applying a scanning voltage to one scanning line, supplying a predetermined data voltage to each data line, and measuring a current value flowing through the electroluminescent element; Applying a scanning voltage to the same scanning line again and supplying each data line with a data signal for setting the electroluminescent element to 0 gradation is performed on each scanning line, and based on the obtained current measurement value. By correcting the data voltage, uniform gradation display can be realized.
JP 2002-278513 A

  By the way, in the active matrix type organic EL display, when an image is displayed, the driving current of the organic EL element flows even in a pixel that is not selected. Therefore, the organic EL display is performed in units of all pixels connected to one data line. When the drive current of the element is measured, the drive current of the organic EL element of the selected pixel cannot be measured unless some countermeasure is taken. The electro-optical device disclosed in Patent Document 1 is also configured to measure the drive current of the electroluminescent element (organic EL element) in units of all pixels connected to one data line. Arise. Therefore, in the electro-optical device disclosed in Patent Document 1, the driving current of the electroluminescent element is allowed to flow only in the selected pixel. In other words, the driving current of the electroluminescent element is allowed to flow in the selected pixel. In the configuration in which the drive current of the electroluminescent element is measured in every pixel unit connected to one data line so that the drive current of the electroluminescent element does not flow in the non-selected pixel, The drive current of the electroluminescent element is appropriately measured.

  However, in the electro-optical device disclosed in Patent Document 1, since it is necessary to prevent the drive current of the electroluminescent element from flowing in unselected pixels, current measurement for data voltage correction is performed. Has a problem that image display cannot be performed.

  The present invention has been made to solve such a problem, and has a simple pixel circuit, and measures the drive current of a light emitting element selected during image display to measure the drive active element. An object of the present invention is to provide an image display apparatus capable of correcting luminance unevenness caused by non-uniform characteristics and a driving method thereof.

  In order to solve the conventional problem, an image display device according to the present invention corresponds to a pixel matrix in which a plurality of pixels are arranged on a matrix and one of rows and columns (hereinafter, one line) of the pixel matrix. A plurality of scanning lines, a plurality of data lines provided corresponding to the other of the rows and columns of the pixel matrix (hereinafter referred to as the other line), and a drive provided to the pixels through which a driving current flows. A current path, a light emitting element provided on the drive current path and emitting light at a luminance corresponding to the drive current, and a drive active provided on the drive current path and controlling the drive current according to the value of the data signal And a transmission path of the data signal to the drive active element in response to the input and stop of the selection signal from the scan line, provided to each pixel and the scan line corresponding to each pixel. Less than, Data signal transmission path), a scanning line driving circuit for sequentially outputting the selection signal to the plurality of scanning lines over a data writing period, and the plurality of scanning line driving circuits. A data line driving circuit for outputting the corresponding data signal to each of the plurality of data lines in accordance with the sequential output of the selection signal to the scanning line, and the other line of the pixel matrix, A plurality of current lines through which a drive current flowing into a drive current path of all pixels belonging to each other line or a drive current flowing out of a drive current path of all pixels belonging to each other line flows, and each of the current lines A current measuring element for measuring the current of the current, a current memory for storing a current value of each streamline measured by the current measuring element, and a current memory stored in the current memory Correction value calculation means for calculating a correction value of the value of the data signal using a flow value; a correction value memory for storing the correction value calculated by the correction value calculation means; and an image signal input from the outside. Writing means for converting the data signals corresponding to the plurality of scanning lines using the correction values stored in the correction value memory and outputting the data signals to the data line driving circuit, the scanning line driving circuit comprising: Further, the writing unit is configured to sequentially output the selection signal over a reference value writing period before the data writing period for each scanning line group including one or more adjacent scanning lines. Is configured to generate the data signal having a reference value and a value corresponding to the luminance of a pixel of the input image signal, and output the data signal to the data line driving circuit. The drive circuit includes the reference value corresponding to each of the plurality of data lines in accordance with the output of the selection signal over the reference value writing period and the data writing period to the plurality of scanning lines by the scanning line driving circuit. And a data signal having a value corresponding to the luminance of the pixel of the image signal, and the correction value calculating means is configured to output the reference value for each data line in the last scanning line of the scanning line group. The current memory of the corresponding current line in the period from when the selection signal corresponding to the value writing period is output until the selection signal corresponding to the data writing period is output in the first scanning line of the certain scanning line group And a selection signal corresponding to the data writing period is output in the first scanning line of the certain scanning line group. The current stored in the current memory of the corresponding current line in the period until the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the certain scanning line group. A difference from the value is calculated, and the correction value is calculated based on the calculated difference.

  With such a configuration, the scanning line driving circuit sequentially outputs a selection signal to a plurality of scanning lines over a data writing period, and the scanning signal driving circuit sequentially selects the selection signals to the plurality of scanning lines. The data line driving circuit outputs the corresponding data signal to each of the plurality of data lines in accordance with the output, whereby an image corresponding to the image signal is displayed on the image matrix. On the other hand, the scanning line driving circuit further outputs a selection signal sequentially over the reference value writing period before the data writing period for each scanning line group including one or more scanning lines, and the data line driving circuit The pixel of the reference value and the image signal respectively corresponding to the plurality of data lines according to the output of the selection signal over the reference value writing period and the data writing period to the plurality of scanning lines by the scanning line driving circuit. By outputting a data signal having a value corresponding to the luminance of the pixel, a driving current corresponding to the reference value flows in a period from the start of the reference value writing period to the start of the data writing period in each row of pixels, and the data writing period After starting, a drive current corresponding to a value corresponding to the luminance of the pixel of the image signal flows. In addition, the correction value calculating means outputs, for each data line, the last scanning line of the certain scanning line group after the selection signal corresponding to the reference value writing period is output in the last scanning line of the certain scanning line group. The current value stored in the current memory of the corresponding current line in the period until the selection signal corresponding to the data writing period is output, and in the data writing period in the first scanning line of the certain scanning line group The corresponding current line in the period from when the corresponding selection signal is output until the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the certain scanning line group. By calculating the difference from the current value stored in the current memory, at least the pixel of the image signal for each pixel in the row group corresponding to the scanning line group. Difference between the driving current corresponding to the reference value and the driving current corresponding to a value corresponding to the time is calculated. Then, for example, by distributing this difference using a value corresponding to the luminance of the pixel of the image signal in the pixel of the row corresponding to each scanning line constituting the scanning line group, each scanning constituting the scanning line group is performed. The difference between the drive current corresponding to the value corresponding to the luminance of the pixel of the image signal in the pixel in the row corresponding to the line and the drive current corresponding to the reference value can be calculated. This difference reflects the characteristics of the pixel drive active element. Then, the correction value calculation means calculates the correction value based on this difference, and the writing means converts the input image signal into a data signal using this correction value, resulting in non-uniform characteristics of the drive active element. Brightness unevenness can be corrected. Moreover, the pixel circuit is simple because it is not different from the conventional one. That is, with such a configuration, the pixel has a simple pixel circuit, and the driving current of the selected light emitting element is measured during the image display, resulting in uneven luminance due to non-uniform characteristics of the driving active element. Can be corrected.

  One scanning line may be included in the scanning line group.

  Two scanning lines may be included in the scanning line group.

  The correction value calculating means outputs, for each data line, the first scanning line of the certain scanning line group after the selection signal corresponding to the reference value writing period is output in the last scanning line of the certain scanning line group. The current value stored in the current memory of the corresponding current line in the period until the selection signal corresponding to the data writing period is output, and the data writing period in the last scanning line of the certain scanning line group The corresponding current line in the period from when the selection signal to be output to when the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the certain scanning line group. The difference between the current value stored in the current memory and the luminance of the pixel of the image signal in the pixel of the row corresponding to each scanning line constituting the scanning line group is calculated. By distributing the difference using the corresponding value, the driving current corresponding to the value corresponding to the luminance of the pixel of the image signal in the pixel of the row corresponding to each scanning line constituting the scanning line group and the reference You may be comprised so that the difference with the drive current corresponding to a value may be calculated.

  With such a configuration, the difference between the driving current corresponding to the value corresponding to the luminance of the pixel of the image signal for each pixel in the row group corresponding to the scanning line group and the driving current corresponding to the reference value is calculated. However, by distributing this, a drive current corresponding to a value corresponding to a luminance of a pixel of the image signal in a pixel in a row corresponding to each scan line constituting the scan line group and a drive corresponding to the reference value It is possible to accurately calculate the difference from the current.

  The scanning line driving circuit may be configured to output the selection signal so that the reference value writing period is located in a vertical blanking period of a vertical synchronization signal.

  The scanning line driving circuit may be configured to output the selection signal over the reference value writing period so as to be delayed by one or more frame periods in order for each scanning line group.

  The image display device includes one current measuring element and a switch circuit that selectively connects the plurality of current lines to the current measuring element sequentially, and the current memory includes a current measured by the current measuring element. A value may be stored in association with each current line.

  The image display device driving method of the present invention is provided corresponding to a pixel matrix in which a plurality of pixels are arranged on a matrix and one of the rows and columns (hereinafter, one line) of the pixel matrix. A plurality of scanning lines, a plurality of data lines provided corresponding to the other of the rows and columns of the pixel matrix (hereinafter referred to as the other line), a driving current path provided in the pixel and through which a driving current flows, A light-emitting element that is provided on the drive current path and emits light at a luminance corresponding to the drive current; a drive active element that is provided on the drive current path and controls the drive current according to a value of a data signal; A transmission path (hereinafter referred to as data signal transmission) of the data signal to the driving active element is provided in a pixel connected to the scanning line corresponding to each pixel, and in response to input and stop of a selection signal from the scanning line Sutra ) Are opened and shut off, a scanning line driving circuit for sequentially outputting the selection signal to the plurality of scanning lines over a data writing period, and the scanning line driving circuit to the plurality of scanning lines. A data line driving circuit for outputting a corresponding data signal to each of the plurality of data lines in accordance with the sequential output of the selection signal, provided corresponding to the other line of the pixel matrix, A plurality of current lines through which a drive current flowing into a drive current path of all pixels belonging to or a drive current flowing out of a drive current path of all pixels belonging to the other line flows, and the currents of the current lines are measured. A current measuring element for storing the current value of each streamline measured by the current measuring element, and a current value stored in the current memory A correction value calculating means for calculating a correction value for the value of the data signal, a correction value memory for storing the correction value calculated by the correction value calculating means, and an image signal input from the outside are stored in the correction value memory. And a writing unit that converts the data signal corresponding to the plurality of scanning lines using the correction value and outputs the data signal to the data line driving circuit. The line driving circuit further outputs the selection signal sequentially over a reference value writing period before the data writing period for each scanning line group composed of one or more adjacent scanning lines, and the writing means The data signal having a reference value and a value corresponding to the luminance of the pixel of the input image signal is generated and output to the data line driving circuit, and the data line driving circuit According to the output of the selection signal over the reference value writing period and the data writing period to the plurality of scanning lines by the moving circuit, the reference value and the pixel of the image signal corresponding to the plurality of data lines, respectively. A data signal having a value corresponding to the luminance is output, and the correction value calculating means outputs a selection signal corresponding to the reference value writing period in the last scanning line of the scanning line group for each data line. Current value stored in the current memory of the corresponding current line in a period until the selection signal corresponding to the data writing period is output in the first scanning line of the certain scanning line group, and the certain scanning line After the selection signal corresponding to the data writing period is output on the first scan line of the group, the first scan line group of the next scan line group after the selection signal is output. Calculating a difference between the current value stored in the current memory of the corresponding current line in a period until the selection signal corresponding to the reference value writing period is output in the line, and based on the calculated difference A correction value is calculated.

  With such a configuration, as described above, the pixel circuit has a simple pixel circuit, and the drive current of the selected light emitting element is measured during image display, resulting in non-uniform characteristics of the drive active element. Brightness unevenness can be corrected.

  The correction value calculating means outputs, for each data line, the first scanning line of the certain scanning line group after the selection signal corresponding to the reference value writing period is output in the last scanning line of the certain scanning line group. The current value stored in the current memory of the corresponding current line in the period until the selection signal corresponding to the data writing period is output, and the data writing period in the last scanning line of the certain scanning line group The corresponding current line in the period from when the selection signal to be output to when the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the certain scanning line group. The difference between the current value stored in the current memory and the luminance of the pixel of the image signal in the pixel of the row corresponding to each scanning line constituting the scanning line group is calculated. By distributing the difference using the corresponding value, the driving current corresponding to the value corresponding to the luminance of the pixel of the image signal in the pixel of the row corresponding to each scanning line constituting the scanning line group and the reference A difference from the drive current corresponding to the value may be calculated.

  With such a configuration, as described above, the driving current corresponding to the value corresponding to the luminance of the pixel of the image signal in the pixel of the row corresponding to each scanning line constituting the scanning line group and the reference value are set. It is possible to accurately calculate the difference from the corresponding drive current.

  The scanning line driving circuit may output the selection signal so that the reference value writing period is located in a vertical blanking period of a vertical synchronization signal.

  The scanning line driving circuit may output the selection signal over the reference value writing period so as to be delayed by one or more frame periods in order for each scanning line group.

  One current measuring element and a switch circuit for sequentially and selectively connecting the plurality of current lines to the current measuring element, and the current memory stores a current value measured by the current measuring element in each current line. And may be stored in correspondence.

  The present invention is configured as described above, and in the image display apparatus and the driving method thereof, has a simple pixel circuit, and measures the drive current of the light emitting element selected during the image display to drive the display active. There is an effect that it is possible to correct luminance unevenness caused by non-uniformity of element characteristics.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals throughout all the drawings, and redundant description thereof is omitted.

(Embodiment 1)
FIG. 1 is a block diagram showing an electrical configuration of an image display apparatus according to Embodiment 1 of the present invention. FIG. 2 is a circuit diagram showing a configuration of a pixel circuit of the image display apparatus of FIG. FIG. 3 is a circuit diagram showing the configuration of the current measuring element of the image display apparatus of FIG.

  As shown in FIG. 1, the image display device 170 is configured by an organic EL display in the present embodiment. The image display device 170 includes a pixel matrix 10 that is a display screen, a scanning line driving circuit 100, a data line driving circuit 110, a current supply power source 120, a current extraction power source 130, and current measuring elements 24-1 to 24-. m and a controller 30 as main components.

  Here, the pixel matrix 10 is composed of pixels P11 to Pnm arranged in a matrix of n rows and m columns. The pixels P11 to Pnm of n rows and m columns are composed of n scanning lines 20-1 to 20-n and m data lines 21-1 to 21-m, which are orthogonal to each other when viewed from the normal direction of the display screen. And a matrix area on the display screen. The n scanning lines 20-1 to 20-n are formed so as to extend along the row of the pixel matrix 10 at equal intervals, and the base ends thereof are connected to the scanning line driving circuit 100, and the tip ends thereof. It is open. The m data lines 21-1 to 21-m are formed so as to extend along the columns of the pixel matrix 10 at equal intervals, and the base ends thereof are connected to the data line driving circuit 110, and the tip ends thereof. It is open.

  The current supply power source 120 is configured by a voltage source that applies a predetermined potential, and a common current supply line 22-0 is connected to an output terminal thereof. Then, m current supply lines (current lines) 22-1 to 22-m extending along the columns of the pixel matrix 10 are connected to the common current supply line.

  The current extraction power source 130 is configured by a voltage source that applies a predetermined potential (here, a potential lower than the potential applied by the current supply power source), and a common current extraction line 23-0 is connected to an output terminal thereof. . The m current lead lines (current lines) 23-1 to 23 -m extending along the columns of the pixel matrix 10 are connected to the common current lead line. The current lead wires 23-1 to 23-m are connected to the common current lead wire 23-0 through current measuring elements 24-1 to 24-m described later.

  Next, the configuration of the pixel will be described. As shown in FIG. 2, a pixel circuit 300 for operating the light emitting element 323 is formed in each of the pixels P11 to Pnm. The pixel circuit 300 has a drive current path 324. The drive current path 324 is formed to connect the current supply lines 23-1 to 23-m and the current lead lines 24-1 to 24-m. On the drive current path 324, a current drive type light emitting element 323 and a driving transistor 321 as a drive active element are provided. Here, the light emitting element 323 is composed of an organic EL element. Of course, other current-driven light emitting elements may be used. Here, the driving transistor 321 is composed of a P-channel TFT. The source of the driving transistor 321 is connected to the current supply lines 23-1 to 23 -m, and the drain of the driving transistor 321 is connected to the anode of the light emitting element 323. The cathode of the light emitting element 323 is connected to the current lead lines 24-1 to 24-m. A capacitor 322 is connected between the source and gate of the driving transistor 321. The gate of the driving transistor 321 is connected to the data lines 21-1 to 21-m via the switching transistor 320. Here, the switching transistor 320 is formed of a P-channel TFT. The drain (or source) of the switching transistor 320 is connected to the data line, and the source (or drain) of the switching transistor 320 is connected to the gate of the driving transistor 321. The gate of the switching transistor 320 is connected to the scanning lines 20-1 to 20-n. As a result, when a selection signal (LOW level portion in the scanning signal in FIG. 4) is output to the scanning lines 20-1 to 20-n, the switching transistor 320 is turned on and the data lines 21-1 to 21-m are turned on. A data signal is input to the gate of the driving transistor 321. Here, the data signal is a voltage signal, and a voltage corresponding to the value of the data signal is applied to the gate of the driving transistor 321 and held in the capacitor 322. As a result, the driving transistor 321 passes a driving current corresponding to the value of the data signal through the driving current path 324, and the light emitting element 323 emits light with a luminance corresponding to the driving current. Further, since the voltage corresponding to the value of the data signal is held in the capacitor 322, the light emitting element 323 is not changed until the next data signal is input to the gate of the driving transistor 321 even after the switching transistor 320 is turned off. The light continues to be emitted at a luminance corresponding to the value of the data signal. As described above, as the driving method of the light emitting element 323, the voltage driving method is adopted here, but a current program method may be adopted. The pixel circuit 300 is not limited to the configuration in FIG. 2 and may be any circuit that is suitable for the driving method of the light emitting element 323.

  As shown in FIG. 1, current measuring elements 24-1 to 24-m for measuring respective currents are provided at the downstream ends of the m current lead lines 23-1 to 23-m, respectively. As shown in FIG. 3, the current measuring elements 24-1 to 24-m include, for example, a resistor R provided at the downstream end of the current leaders 23-1 to 23-m, and a voltage across the resistor R. And an A / D converter 41 that converts an analog detection signal output from the voltage sensor 40 into a digital detection signal. The voltage value detected by the voltage sensor 40 is converted into a current by a correction value calculation unit 153 of the controller 30 described later. In the present embodiment, the current measuring elements 24-1 to 24-m are provided in the current lead lines 23-1 to 23-m as described above, but the current supply lines 22-1 to 22-m are provided. It may be provided at the upstream end portion.

  As shown in FIG. 1, current values (voltage values in the configuration example of FIG. 3) measured by the current measuring elements 24-1 to 24-m are temporarily stored in the current memory 140. The current memory 140 is provided with a storage area for each of the current measurement elements 24-1 to 24-m, and current values measured by the current measurement elements 24-1 to 24-m are stored in the respective storage areas. The This current value is stored so as to be sequentially updated.

  The controller 30 includes a calculation unit 150, a control unit 151, and a correction value memory 160. The calculation unit 150 includes a writing unit 152 and a correction value calculation unit 153. The controller 30 is composed of, for example, a microcomputer, and the CPU executes a predetermined program stored in its internal memory, whereby the function of the writing unit 152, the function of the correction value calculating unit 153, and the control unit 151 are controlled. Function is realized. The correction value memory 160 is for storing a correction value, which will be described later, and is composed of, for example, an internal memory of a microcomputer.

  An image signal is input to the writing unit 152. The writing unit 152 converts the input image signal into a data signal. This data signal is a signal obtained by converting the luminance (gradation) of a pixel in the image signal into a digital signal corresponding to the gate voltage of the driving transistor 321 that causes the light emitting element 323 to emit light with the luminance. The writing unit 152 processes the data signal so that a display of a reference value (here, a black value (luminance 0)) is inserted in each pixel. The processing for inserting the reference value display may be performed by the data line driving circuit 110. The correction value calculation unit 153 uses the current measurement values of the current measurement elements 24-1 to 24-m input from the current memory 140 to cause the data signal value (the light emitting element 323 to emit light with the luminance of the pixel in the image signal). The correction value (digital value corresponding to the gate voltage of the driving transistor 321) is calculated and stored in the correction value memory 160 in correspondence with the pixel in the image signal.

When the writing unit 152 converts the luminance of the pixel in the image signal into a digital signal corresponding to the gate voltage of the driving transistor 321, the writing unit 152 performs data using the correction value corresponding to the pixel stored in the correction value memory 160. Correct the signal value. This correction will be described in detail later. The writing unit 152 outputs the data signal thus generated to the data line driving circuit 110. The writing unit 152 stores the value of the generated data signal in a predetermined memory (not shown) so as to be sequentially updated. The value of the stored data signal is used for calculation of a correction value by the correction value calculation unit 153 as will be described later.
The data line driving circuit 110 divides the input data signal into signals corresponding to the data lines 21-1 to 21-m and converts them into voltage signals for driving the driving transistor 321. Then, the data signal thus converted is output to the data lines 21-1 to 21-m. Data signals output to the data lines 21-1 to 21-m will be described in detail later.

  The control unit 151 controls the entire operation of the image display device 170. For example, the control unit 151 controls the scanning line driving circuit 100 and the data line driving circuit 110 to match the selection signal output of the scanning line driving circuit 100. The data line driving circuit 110 is made to output a data signal.

  The correction value memory 160 may be constituted by a single memory together with the current memory 140.

  Next, a configuration for correcting the non-uniformity of the characteristics of the driving transistor 321 that characterizes the present invention will be described with reference to FIGS.

  FIG. 4 is a timing chart showing the acquisition timing of the current value used for correcting the data signal.

  In FIG. 4, the horizontal axis represents time t. In the vertical direction of FIG. 4, in order from the top, the waveform diagram of the scanning signal of the first row, the waveform diagram of the scanning signal of the second row, the waveform diagram of the scanning signal of the third row, the waveform diagram of the data signal, the first row The waveform diagram which shows the light emission state of the pixel of this, the waveform diagram which shows the light emission state of the pixel of the 2nd row, and the waveform diagram which shows the light emission state of the pixel of the 3rd row are shown. In the waveform diagram of the scanning signal in the first row, the waveform diagram of the scanning signal in the second row, and the waveform diagram of the scanning signal in the third row, the vertical axis represents the signal level. Hereinafter, “a scanning signal of a scanning line in a certain row” is abbreviated as “a scanning signal of a certain row”.

  As shown in the upper part of FIG. 4, the scanning line driving circuit 100 outputs the following scanning signal to the scanning line 20-1 in the first row. For example, in one frame period, the scan signal includes a normal data writing period D2 from time t3 to time t4, a reference value writing period D1 from time t1 to time t2 slightly before the data writing period D2, and Becomes LOW level, and becomes HIGH level in other periods. When this scanning signal becomes the LOW level, all the switching transistors 320 whose gates are connected to the scanning line 20-1 are turned on. Thereby, all the pixels P11 to P1m in the first row are selected. When this scanning signal becomes a HIGH level, all the switching transistors 320 whose gates are connected to the scanning line 20-1 are turned off. Thereby, all the pixels P11 to P1m in the first row are not selected. That is, the portion of the scanning signal that is at the LOW level constitutes a selection signal, and the portion of the scanning signal that is at the HIGH level constitutes a non-selection signal.

  Then, the scanning line driving circuit 100 applies the reference value writing period D1 (period extending from time t5 to time t6) to the scanning line 20-2 of the second row, which is the next row, similarly to the scanning signal of the first row. And a data writing period D2 (a period from time t7 to time t8), and the start time t5 of the reference value writing period D1 is a predetermined time T0 from the start time t1 of the reference value writing period D1 of the first row scanning signal. A scanning signal delayed by (time from time t1 to time t5) is output. The predetermined time T0 is a time slightly longer than the total time of the reference value writing period D1 and the data writing period D2. The scanning line driving circuit 100 has a reference value writing period D1 and a data writing period D2 as well as these scanning signals for the scanning lines of the subsequent rows, and the start time of the reference value writing period D1 is the immediately preceding row. A scanning signal delayed by a predetermined time T0 from the start of the reference value writing period D1 of the scanning signal is output. That is, the scanning line driving circuit 100 has the reference value writing period D1 and the data writing period D2 for the first to n-th scanning lines in one frame period, and the start time of the reference value writing period D1. Outputs a scanning signal delayed by a predetermined time T0 from the start time of the reference value writing period D1 of the scanning signal of the immediately preceding row. Thereby, in one frame period, one scanning line is sequentially selected with a delay of a predetermined time T0. Therefore, in the pixel matrix 10, only one row of pixels is always selected, and only one pixel is selected in one column.

  On the other hand, as shown in the middle part of FIG. 4, the data line driving circuit 110 becomes the reference value (here black value (luminance 0)) RF1 in the reference value writing period D1 for the pixels in the first row, and the data writing In the period D2, a data signal having a value DT1 corresponding to the luminance of the pixel of the image signal is output. Needless to say, this data signal differs depending on the column. Thereafter, the data line driving circuit 110 outputs a data signal that becomes the reference value RF2 in the reference value writing period D1 and becomes the value DT2 corresponding to the luminance of the pixel of the image signal in the data writing period D2 for the pixels in the second row. To do. Hereinafter, similarly, the data line driving circuit 110 sequentially becomes the reference value in the reference value writing period D1 with respect to the pixels in the selected row as time passes, and the pixel of the image signal in the data writing period D2 A data signal having a value corresponding to the luminance is output.

  Accordingly, only one row of pixels is sequentially selected in one frame period. In the pixels in the selected row, first, a reference value data signal is input to the driving transistor 321 and held in the capacitor 322 in the reference value writing period D1 (hereinafter, this may be referred to as a value being written). ). Accordingly, the driving transistor 321 passes a driving current (here, 0) corresponding to the reference value through the driving current path 324, whereby the light emitting element 323 emits light with a luminance corresponding to the reference value (here, emission is stopped). ). Thereafter, when the reference value writing period D1 ends, the input of the reference value data signal to the driving transistor 321 is stopped, and the voltage corresponding to the reference value of the data signal (the voltage corresponding to the black value) is the capacitor. Since it is held at 322, the light emitting element 323 continues to emit light with a luminance corresponding to the reference value (here, light emission is continuously stopped).

  Next, a data signal having a value corresponding to the luminance of the pixel of the image signal is input to the driving transistor 321 and held in the capacitor 322 in the data writing period D2. As a result, the driving transistor 321 passes a driving current corresponding to the luminance of the pixel of the image signal through the driving current path 324, whereby the light emitting element 323 emits light with the luminance of the pixel of the image signal. Thereafter, when the data writing period D2 ends, the input of the data signal having a value corresponding to the luminance of the pixel of the image signal to the driving transistor 321 is stopped, but this data signal corresponds to the luminance of the pixel of the image signal. Since the voltage corresponding to the value is held in the capacitor 322, the light emitting element 323 continues to emit light with the luminance of the pixel of the image signal.

  That is, in the pixel of the selected row, in one frame period, a driving current corresponding to the reference value flows until the data writing period D2 starts after the reference value writing period D1 starts (here, the driving current does not flow). In the remaining period, a driving current corresponding to the luminance of the pixel of the image signal flows. That is, the remaining period is a so-called light emission period. This row selection is performed sequentially for all the rows, and the reference time writing period D1 starts between the reference value writing period D1 and the data writing period between the scanning signals of two adjacent rows. It is shifted by a predetermined time T0 that is slightly longer than the total time with D2. Therefore, in the entire pixel matrix 10, in the period from the start of the reference value writing period D1 to the end of the data writing period D2 in the pixels of the selected row, the pixels of the image signal in all the remaining rows of pixels. A drive current corresponding to the luminance flows. Therefore, the total value of the drive currents flowing through all the pixels belonging to one column is selected during the period from the start of the reference value writing period D1 to the end of the data writing period D2 in the scanning signal of the selected pixel. The difference between the driving current corresponding to the luminance of the pixel of the image signal and the driving current corresponding to the reference value in the pixel changes. Since the difference in drive current depends on the characteristics of the driving transistor 321 (more precisely, the gate voltage-drain current characteristic (Vgs-Id characteristic)), the difference in the drive current is detected by detecting the difference in the drive current. Data for compensating the characteristics of the driving transistor 321 can be obtained. Moreover, since all the pixels of the pixel matrix 10 are selected at the time of image display, data for compensating the characteristics of the driving transistor 321 can be individually obtained for all the pixels.

  Therefore, in the present embodiment, the correction value calculation unit 153 writes the reference value in the scanning signal of a certain row among the current values measured by the current measuring elements 24-1 to 24-m and stored in the current memory 140. The current value at the time between the end time of the period D1 and the start time of the data writing period D2, the end time of the data writing period D2 in the scanning signal of the certain row, and the reference value writing period D1 in the scanning signal of the next row A current value at a time between the start time and the current time is acquired, and the former is subtracted from the latter to calculate a difference in drive current in the selected pixel. In the following, the current value (measured by the current measuring elements 24-1 to 24-m and the current memory 140 when the drive current corresponding to the reference value flows in the pixel for which the difference of the drive current is calculated flows. Current value) is referred to as first current value acquisition timing, and the time when the current value is acquired when the drive current corresponding to the luminance of the pixel of the image signal flows is the second current value. This is called acquisition timing. Here, TS1 is the first current value acquisition timing, and TS2 is the second current value acquisition timing.

  For example, the correction value calculation unit 153 obtains the first current value between the end time t2 of the reference value writing period D1 and the start time t3 of the data writing period D2 in the scanning signal of the first row for the pixels of the first row. The second current value acquisition timing TS2 between the current value at the timing TS1 and the end time t4 of the data writing period D2 in the first row scanning signal and the start time t5 of the reference value writing period D1 in the second row scanning signal. Current value at. In this case, at the first current value acquisition timing TS1, the current measured by the current measuring element 24-1 is the sum of the currents flowing through the light emitting elements 323 of all the pixels P11 to Pn1 connected to the current lead line 23-1. The breakdown of the current flows through the light emitting element 323 of the pixel P11 in the first row (the driving current corresponding to the reference value (here, the driving current corresponding to black, that is, the leakage current of the driving transistor 321)), and this The current flows through the light emitting elements 323 of the pixels other than (the drive current corresponding to the luminance of the pixels of the image signal). At the second current value acquisition timing TS2, the current measured by the current measuring element 24-1 is the current that flows through the light emitting elements 323 of all the pixels P11 to Pn1 connected to the current lead line 23-1. Of the driving current corresponding to the luminance of the current.

  Here, between the first current value acquisition timing TS1 and the second current value acquisition timing TS2, the value of the drive current flowing through the light emitting element 323 is changed only in the pixels of the first row, and the other rows. The value of the drive current that flows through the light emitting element 323 of the pixel of this pixel has not changed.

  Taking the current measuring element 24-1 as an example, only the driving current flowing through the light emitting elements 323 of the pixels 11 in the first row changes, and the driving current flowing through the light emitting elements 323 of the other pixels does not change. Therefore, the current value measured at the first current value acquisition timing TS1 by the current measurement element 24-1 is I (TS1), the current value measured at the second current value acquisition timing TS2 is I (TS2), and the first current is measured. The value of the drive current flowing through the light emitting element 323 of the pixel P11 at the value acquisition timing TS1 is I_P11 (reference), and the value of the drive current flowing through the light emitting element 323 of the pixel P11 at the second current value acquisition timing TS2 is I_P11 (IMAGE). Then, the following formula is established.

I (TS2)-I (TS1) = I_P11 (IMAGE)-I_P11 (reference) (1)
Therefore, by measuring in advance the drive current that flows when the reference value (here, the black value) is written, the value of the data signal (here, the voltage value) corresponding to the luminance of the pixel of the image signal is obtained. The value I_P11 (IMAGE) of the drive current when supplied from the data line 21-1 is known. That is, in the driving transistor 321, the drain current when a certain gate voltage is applied can be known. Here, the measurement of the drive current that flows when the reference value is written may be performed before shipment of the image display device 170, and when the image display is finished and the power is turned off after shipment of the image display device 170. It may be automatically performed. The driving current corresponding to the reference value sequentially selects one row, and the driving current corresponding to the reference value is supplied to the light emitting element in the pixel of the selected row, but the light emitting element is supplied to the light emitting element in the pixel that is not selected. The driving current is not supplied (a black value data signal is written in advance).

  The reference value does not have to be a black value (luminance 0), and may be an arbitrary luminance (gradation). However, if the reference value is high luminance (bright gradation), flickering such that a bright screen shines between image displays occurs, so low luminance (dark gradation) is preferable.

  The correction value calculation unit 153 performs the driving of all the pixels P11 to P1m in the first row by performing the calculation of the equation (1) for the current values measured by the current measuring elements 24-1 to 24-m. The drain current value of the transistor 321 with respect to the written gate voltage (data signal value) is calculated. The written gate voltage (data signal value) is read from the predetermined memory and used.

  Similarly, the correction value calculation unit 153 acquires the current values at the first current value acquisition timing TS3 and the second current value acquisition timing TS4, so that the driving transistors 321 of all the pixels P21 to P2m in the second row are obtained. Then, the drain current value with respect to the written gate voltage (data signal value) is calculated.

  Similarly, the correction value calculation unit 153 acquires the current values at the first current value acquisition timing TS5 and the second current value acquisition timing TS6, thereby driving the driving transistors of all the pixels P31 to P3m in the third row. A drain current value corresponding to the written gate voltage (data signal value) 321 is calculated.

  Further, the correction value calculation unit 153 acquires the current values measured by the current measurement elements 24-1 to 24-m for various data signals over a plurality of frames, and the equation (1) By performing the calculation, the gate voltage-drain current characteristics of the driving transistor 321 are obtained in each of the pixels P11 to Pnm.

  Then, the correction value calculation unit 153 represents the gate voltage-drain current characteristic of the driving transistor 321 in an appropriate format and stores it in the memory 160.

  Next, a data signal correction method will be described.

  In this embodiment, the value of the data signal is corrected by correcting the gate voltage-drain current characteristics of the driving transistor 321 used when converting the luminance of the pixel of the input image signal into the data signal.

  FIG. 5 is a graph showing a characteristic of a change in drain current (hereinafter referred to as gate voltage-drain current characteristic) with respect to a change in voltage (hereinafter referred to as gate voltage) between the source and gate of the driving transistor. In FIG. 5, the horizontal axis represents gate voltage (Vgs), and the vertical axis represents drain current (Id).

  When the drain current calculated as described above and the gate voltage written at this time are plotted on the gate voltage-drain current plane for the driving transistor 321 of each pixel P11 to Pnm, the gate voltage-drain current characteristic of the driving transistor 321 is plotted. Is obtained. Here, the written gate voltage is a gate voltage corresponding to the luminance of the pixel of the input image signal (a gate formed by converting the luminance using the gate voltage-drain current characteristics of the driving transistor of each pixel. Voltage).

  In the present embodiment, this gate voltage-drain current characteristic is represented by the following approximate expression (2).

Id = (W / 2L) μCox (Vgs−Vt) ^ 2 (2)
Here, W is the gate width, L is the gate length, μ is the carrier mobility, Cox is the gate capacitance, and Vt is the threshold voltage. The correction value calculation unit 153 stores the equation (2) in the predetermined memory described above.

  Then, the correction value calculation unit 153 obtains the previous measurement data (the drain current Id1 and the written gate voltage Vgs1) and the current measurement data (the drain current Id2 and the written gate voltage Vgs2) in the same pixel ( Substituting into the equation (2), μ and Vt are obtained, and these are stored in the correction value memory 160 as the correction values of the data signal values in association with the corresponding pixels. Each time a new drain current Id and a written gate voltage Vgs are obtained, μ and Vt are calculated, and μ and Vt stored in the memory 160 are updated to the newly calculated μ and Vt.

  Next, the operation of the image display apparatus configured as described above will be briefly described.

  The writing unit 152 converts the input image signal into a data signal. At this time, μ and Vt of each pixel are read from the correction value memory 160, and μ, Vt, and a drain current Id that causes the light emitting element 323 to emit light with the luminance of the pixel of the input image signal are (2 ) To obtain Vgs. This Vgs is used as the value of the data signal of the pixel. Here, the drain current Id that causes the light emitting element 323 to emit light with the luminance of the pixel of the input image signal is obtained from a predetermined driving current-light emission luminance characteristic of the light emitting element 323. The writing unit 152 stores a predetermined low drive current-light emission luminance characteristic of the light emitting element 323 in the predetermined memory.

  As described above, in this embodiment, the value of the data signal is changed by correcting the gate voltage-drain current characteristics of the driving transistor 321 used when converting the luminance of the pixel of the input image signal into the data signal. It is corrected. Further, the correction of the gate voltage-drain current characteristic of the driving transistor 321 is performed sequentially and continuously.

  The writing unit 152 outputs the corrected data signal to the data line driving circuit 110. The data line driving circuit 110 divides the input data signal into signals corresponding to the data lines 21-1 to 21-m and converts them into voltage signals for driving the driving transistors 321. Output to 1 to 21-m. In accordance with this, the scanning line driving circuit 100 outputs scanning signals to the scanning lines 20-1 to 20-n so as to sequentially select the scanning lines 20-1 to 20-n. As a result, an image corresponding to the image signal is displayed on the pixel matrix 10. At this time, the non-uniformity (variation or deterioration) of the characteristics of the driving transistor 321 of each pixel P11 to Pnm is compensated, and a uniform driving current flows to the light emitting element 323 of each pixel P11 to Pnm. As a result, image display without unevenness is performed. In each of the pixels P11 to Pnm, the reference value is written, and using this, the correction value calculation unit 153 and the writing unit 152 sequentially correct the data signal. Thereby, image display without unevenness can be continuously performed.

  Next, a modified example will be described.

[Modification 1]
This modification is a modification of the switch transistor 320 and the driving transistor 321 of the pixels P11 to Pnm.

  FIG. 6 is a circuit diagram showing a configuration of this modification. As shown in FIG. 6, the switch transistor 330 and the driving transistor 331 are composed of N-channel TFTs. Even with such a configuration, the same effect as the configuration of FIG. 2 can be obtained.

  Note that the switch transistor and the driving transistor may be composed of TFTs having different channel types. When considering the manufacturing process, it is more effective from the viewpoint of manufacturing cost, tact time, yield, etc. to configure only one of the P channel type and N channel type.

[Modification 2]
This modification is a modification of the correction value of the data signal value. In the present modification, the pixels are configured as in Modification 1. The TFT constituting the N-channel type driving transistor 321 is made of amorphous silicon. In such a TFT, μ hardly changes with time, and Vt changes with time. Therefore, in this modification, μ is calculated from the gate voltage-drain current characteristics measured in the initial stage, and this is set as a fixed value. Then, Vt is calculated by substituting the drain current Id obtained as described above and the written gate voltage Vgs into (2), and this calculated Vt is used as a correction value for the value of the data signal. It is stored in the correction value memory 160 in association with the pixel to be corrected. Each time a new drain current Id and a written gate voltage Vgs are obtained, Vt is calculated, and Vt stored in the memory 160 is updated to this newly calculated Vt. According to such a configuration, the calculation of the correction value can be simplified.

[Modification 3]
This modification is a modification of the method for correcting the value of the data signal. In the above-described embodiment, the gate voltage-drain current characteristic itself of the driving transistor used when the image signal is converted into the data signal is corrected. However, in this modification, the gate voltage of the standard (standard) driving transistor− The data signal (gate voltage) converted by the drain current characteristic is corrected. Specifically, the writing unit 152 converts the luminance of the pixel of the input image signal into a data signal using a gate voltage-drain current characteristic of a specified (standard) driving transistor. On the other hand, the correction value calculation unit 153 cancels the deviation of the actual drain current of each pixel calculated by the correction value calculation unit 153 with respect to the drain current that should originally flow in each pixel (the drain current of the specified driving transistor). A correction value of the gate voltage of the driving transistor is calculated, and a lookup table in which the correction value is associated with the luminance of each pixel of the input image signal is created and stored in the correction value memory 160. When the image signal is input, the writing unit 152 converts the image signal into a data signal using the gate voltage-drain current characteristic of the prescribed driving transistor. Then, the correction value of the gate voltage corresponding to the luminance of each pixel of the input image signal is read from the lookup table of the correction value memory 160, and the value of the data signal (the gate voltage value of the driving transistor) is read with these correction values. to correct.

  Even with such a configuration, the same effect as described above can be obtained.

(Embodiment 2)
FIG. 7 is a timing chart showing the acquisition timing of the current value used for correction of the data signal in the image display device according to Embodiment 2 of the present invention.

  As shown in FIG. 7, the present embodiment is different from the first embodiment in the acquisition timing of the current value measured by the current measuring element by the correction value calculation unit 153. The other points are the same as in the first embodiment. In the present embodiment, the first current value acquisition timing TS1 for acquiring the current value measured by the current measuring elements 24-1 to 24-m when the drive current corresponding to the reference value flows in the selected pixel. , TS3, TS5... Are positioned (existing) in the reference value writing period D1, and measured by the current measuring elements 24-1 to 24-m when the drive current corresponding to the luminance of the pixel of the image signal flows. Second current value acquisition timings TS2, TS4, TS6... For acquiring the current value to be acquired are located within the data writing period D2. Even in such a configuration, the same effect as the configuration of FIG. 4 can be obtained.

  That is, the correction current value acquisition timing may be during the reference value writing period D1 and the data writing period D2 as long as the driving current in the selected pixel has settled to a constant value.

(Embodiment 3)
FIG. 8 is a timing chart showing the acquisition timing of the current value used for correcting the data signal in the image display apparatus according to Embodiment 3 of the present invention.

  In this embodiment, the scanning line driving circuit 100 has a reference value writing period D1 and a data writing period D2 for the first to n-th scanning lines in one frame period, and the reference value writing period. A scanning signal in which the start time of D1 is delayed by a predetermined time T0 from the start time of the reference value writing period D1 of the scanning signal of the immediately preceding row is output. The predetermined time TO is a time slightly longer than the total time of the reference value writing period D1 and the data writing period D2. These points are the same as in the embodiment. However, in this embodiment, the data writing period D2 of the scanning signal of the row is between the reference value writing period D1 of the scanning signal of the next row and the reference value writing period D1 of the scanning signal of the next row. positioned.

  Hereinafter, in order to facilitate understanding, the first to third lines will be described as examples.

  The data writing period D2 (time t7 to time t8) of the scanning signal of the first row is the next row, the reference value writing period D1 (time t5 to time t6) of the scanning signal of the second row, and the next row. And the reference value writing period D1 (time t9 to time t10) of the scanning signal of the third row.

  Thereby, as shown in the upper part of FIG. 8, when the reference value writing period D1 of the scanning signal of the first row starts, the reference value RF1 is written to the pixels of the first row, as shown in the middle part of FIG. As shown in the lower part of FIG. 8, the light emitting elements of the pixels in the first row emit light at a luminance corresponding to the reference value RF1, and continue this light emission. That is, the driving current corresponding to the reference value RF1 flows through the pixels in the first row, and this continues. After that, when a predetermined time T0 has elapsed from the start (time t1) of the reference value writing period D1 of the first row scanning signal, as shown in the upper part of FIG. Start (time t5), the reference value RF2 is written to the pixels in the second row as shown in the middle part of FIG. 8, and the light emitting elements of the pixels in the second row as shown in the lower part of FIG. Light is emitted at a luminance corresponding to, and this light emission is continued. That is, the driving current corresponding to the reference value RF2 flows through the pixels in the second row, and this continues. Thereafter, when the reference value writing period D1 of the scanning signal of the second row ends (time t6), after a short time, as shown in the upper part of FIG. Start (time t7). Then, as shown in the middle part of FIG. 8, the value DT1 corresponding to the luminance of the pixel of the image signal is written to the pixels of the first row, and as shown in the lower part of FIG. Light is emitted at a luminance corresponding to the luminance of the pixel of the image signal. That is, a driving current corresponding to the luminance of the pixel of the image signal flows through the pixels in the first row. Thereafter, when a predetermined time T0 has elapsed from the start of the reference value writing period D1 of the second row scanning signal (time t5), the reference value writing period D1 of the third row scanning signal is set as shown in the upper part of FIG. Start (time t9), the reference value RF3 is written into the pixels in the third row as shown in the middle part of FIG. 8, and the light-emitting elements of the pixels in the third row appear as the reference value RF3 as shown in the lower part of FIG. Light is emitted at a luminance corresponding to, and this light emission is continued. That is, the driving current corresponding to the reference value RF3 flows through the pixels in the third row, and this continues. Thereafter, the same operation as described above is repeated until the data write period D2 of the nth row ends.

  Thereby, in the pixel matrix 10, the period from the start of the reference value writing period D1 of the second row scanning signal to the start of the data writing period D2 of the first row scanning signal (period from time t5 to time t7). The driving current corresponding to the reference value flows in the pixels in these two rows, and the driving current corresponding to the luminance of the pixel of the image signal flows in the pixels in the other rows. Then, when the data writing period D2 of the scanning signal of the first row starts (time t7), the driving current corresponding to the reference value flows in the pixels of the second row, and the pixels of the image signal pass to the pixels of the other rows. A drive current corresponding to the luminance of the current flows. Then, when the reference value writing period D1 of the scanning signal of the third row starts (time t9), the driving current corresponding to the reference value flows in the pixels of the two rows of the second row and the third row. A driving current corresponding to the luminance of the pixel of the image signal flows through the pixels in the row. Accordingly, in the pixel matrix 10, the period from the start of the reference value writing period D1 of the second row scanning signal to the start of the reference value writing period D1 of the third row scanning signal (period from time t5 to time t9). ), Only in the pixels in the first row, the value of the drive current flowing through them changes from a value corresponding to the reference value to a value corresponding to the luminance of the pixel of the image signal.

  That is, when this is generalized, in the pixel matrix 10, the reference value writing period D1 of the scanning signal of the next row after the start of the scanning signal reference value writing period D1 of the next row of the certain row is started. In the period until the start of the image, the value of the drive current flowing through only the pixels in the certain row changes from the value corresponding to the reference value to the value corresponding to the luminance of the pixel of the image signal.

  Therefore, in the present embodiment, the first current value acquisition timings TS1, TS3, TS5... And the second current value acquisition timings TS2, TS4, TS6. In the period from the start of the reference value writing period D1 to the start of the reference value writing period D1 of the scanning signal of the row two rows after the certain row, the start time of the data writing period D2 of the scanning signal of the certain row is set. It is set to be positioned so as to sandwich it. Thereby, it is possible to appropriately detect the difference between the drive current corresponding to the luminance of the pixel of the image signal in the pixel of the certain row and the drive current corresponding to the reference value. In the present embodiment, for example, the first current value acquisition timing TS1 is a period (time) from the end of the reference value writing period D1 of the scanning signal of the second row to the start of the data writing period D2 of the scanning signal of the first row. The second current value acquisition timing TS2 is set from the end of the data writing period D2 of the scanning signal of the first row to the start of the reference value writing period D1 of the scanning signal of the third row. The period is set (period from time t8 to time t9).

  As illustrated above, in the present invention, the time difference between the reference value writing period D1 and the data writing period D2 can be arbitrarily set by appropriately selecting the first current value acquisition timing and the second current value acquisition timing. it can.

(Embodiment 4)
FIG. 9 is a timing chart showing the acquisition timing of the current value used for correcting the data signal in the image display apparatus according to Embodiment 4 of the present invention. In the following description, a plurality of adjacent rows is referred to as a row group, and this row group corresponds to a scanning line group including scanning lines of a plurality of adjacent rows. Therefore, in the following, in order to simplify the description, the concept of the row group is used instead of the concept of the scanning line group.

  In the present embodiment, as shown in the upper part of FIG. 9, the scanning line driving circuit 100 performs the reference value writing period D1 and the data writing period D2 with respect to the scanning lines of the first to nth rows in one frame period. For each of a plurality of adjacent (herein, two) rows (hereinafter referred to as row groups), the start time of the reference value writing period D1 of the scanning signal group corresponding to this row group corresponds to the immediately preceding row group. A scanning signal delayed by a predetermined time T2 from the start time of the reference value writing period D1 of the scanning signal group is output. The predetermined time T2 is a time slightly longer than the total time of the reference value writing period D1 and the data writing period D2 of the scanning signals of all the rows (in this case, two rows) constituting one row group. In the scanning signal group corresponding to one row group, the start time of the reference value writing period D1 is delayed by a predetermined time T1 slightly longer than the reference value writing period D1 in the order of the rows.

  Hereinafter, in order to facilitate understanding, the first to fourth lines will be described as an example.

  Here, the adjacent first row and the second row constitute the row group, and the adjacent third row and the fourth row constitute the next row group. Then, a scanning signal in which the start time t9 of the reference value writing period D1 of the scanning signal group corresponding to the next row group is delayed by a predetermined time T2 from the start time t1 of the reference value writing period D1 of the row group is output. The predetermined time T2 is slightly longer than the total time of the reference value writing period D1 and the data writing period D2 of the scanning line signals of the first and second rows constituting one row group (time from time t1 to time t9). It is. Taking the row group as an example of one row group, in the row group, the start time t3 of the reference value writing period D1 of the scanning signal of the second row is the same as the reference value writing period D1 of the first row. There is a delay of a predetermined time T1 slightly longer than the reference value writing period D1 from the start time t1. The same applies to the scanning signal groups in the third row and the fourth row constituting the next row group.

  Looking at this in time series, first, the scanning signal of the first row that is the first row of the row group is the reference value writing period D1, and then the scanning signal of the second row that is the last row of the row group. Becomes the reference value writing period D1, then the scanning signal of the first row which is the first row of the row group becomes the data writing period D2, and then the scanning signal of the second row which is the last row of the row group is The data writing period D2 is entered. Next, the scanning signal of the third row, which is the first row of the next row group, is the reference value writing period D1, and then the scanning signal of the fourth row, which is the last row of the next row group, is the reference value writing period D1. Next, the scanning signal of the third row, which is the first row of the next row group, becomes the data writing period D2, and then, the scanning signal of the fourth row, which is the last row of the next row group, becomes the data writing period D2. It becomes. Thereafter, the same operation is repeated up to the n-th row in one frame period.

  On the other hand, the data line driving circuit 110 outputs data signals as shown in the middle stage of FIG. 9 in accordance with the timings of these scanning line signals. This data signal first becomes the reference value RF1 in the reference value writing period D1 of the scanning signal of the first row, which is the first row of the row group, and then scans the second row, which is the last row of the row group. It becomes the reference value RF2 in the reference value writing period D1 of the signal, and then becomes the value DT1 corresponding to the luminance of the pixel of the image signal in the data writing period D2 of the scanning signal of the first row, which is the first row of the row group. The value DT2 corresponding to the luminance of the pixel of the image signal is obtained during the data writing period D2 of the scanning signal of the second row, which is the last row of the row group. Next, the reference value RF3 is set in the reference value writing period D1 of the scanning signal of the third row, which is the first row of the next row group, and then the reference of the scanning signal of the fourth row, which is the last row of the next row group. It becomes the reference value RF4 in the value writing period D1, then becomes the value DT3 corresponding to the luminance of the pixel of the image signal in the data writing period D2 of the scanning signal of the third row which is the first row of the next row group, and then The value becomes DT4 corresponding to the luminance of the pixel of the image signal during the data writing period D2 of the scanning signal of the fourth row, which is the last row of the row group. Thereafter, the same operation is repeated up to the n-th row in one frame period. The reference values RF1 to RFN are all the same value (here, the black value (luminance 0)).

  As a result, as shown in the upper part of FIG. 9, when the reference value writing period D1 of the scanning signal of the first row starts (time t1), the reference value RF1 is changed to the first row as shown in the middle part of FIG. As shown in the lower part of FIG. 9, the light emitting elements of the pixels in the first row emit light with luminance corresponding to the reference value RF1, and continue this light emission. That is, the driving current corresponding to the reference value RF1 flows through the pixels in the first row, and this continues. Thereafter, when the reference value writing period D1 of the scanning signal of the second row starts (time t3), the reference value RF2 is written to the pixels of the second row as shown in the middle row of FIG. As shown, the light emitting elements of the pixels in the second row emit light with a luminance corresponding to the reference value RF2, and continue this light emission. That is, the driving current corresponding to the reference value RF2 flows through the pixels in the first row, and this continues. Thereafter, as shown in the upper part of FIG. 9, when the data writing period D2 of the scanning signal of the first row starts (time t5), as shown in the middle part of FIG. 9, a value corresponding to the luminance of the pixel of the image signal. DT1 is written into the pixels of the first row, and as shown in the lower part of FIG. 9, the light emitting elements of the pixels of the first row emit light with a luminance corresponding to the value DT1 corresponding to the luminance of the pixel of the image signal. Continue. That is, the driving current corresponding to the value DT1 corresponding to the luminance of the pixel of the image signal flows through the pixels in the first row, and this continues. Thereafter, as shown in the upper part of FIG. 9, when the data writing period D2 of the scanning signal of the second row starts (time t7), a value corresponding to the luminance of the pixel of the image signal as shown in the middle part of FIG. DT2 is written into the pixels of the second row, and as shown in the lower part of FIG. 9, the light emitting elements of the pixels of the second row emit light with a luminance corresponding to the value DT2 corresponding to the luminance of the pixel of the image signal. Continue. That is, the driving current corresponding to the value DT2 corresponding to the luminance of the pixel of the image signal flows through the pixels in the second row, and this continues.

  After that, as shown in the upper part of FIG. 9, when the reference value writing period D1 of the scanning signal of the third row starts (time t9), the reference value RF3 becomes the pixel of the third row as shown in the middle part of FIG. As shown in the lower part of FIG. 9, the light emitting elements of the pixels in the third row emit light at a luminance corresponding to the reference value RF3, and continue this light emission. That is, the driving current corresponding to the reference value RF3 flows through the pixels in the third row, and this continues. Thereafter, when the reference value writing period D1 of the scanning signal of the fourth row starts (time t11), the reference value RF4 is written to the pixels of the fourth row as shown in the middle row of FIG. As shown, the light emitting elements of the pixels in the fourth row emit light with a luminance corresponding to the reference value RF4 and continue this light emission. That is, the drive current corresponding to the reference value RF4 flows through the pixels in the fourth row, and this continues. After that, as shown in the upper part of FIG. 9, when the data writing period D2 of the scanning signal of the third row starts (time t13), as shown in the middle part of FIG. 9, a value corresponding to the luminance of the pixel of the image signal DT3 is written into the pixels of the third row, and as shown in the lower part of FIG. 9, the light emitting elements of the pixels of the third row emit light with a luminance corresponding to the value DT3 corresponding to the luminance of the pixel of the image signal. Continue. That is, the driving current corresponding to the value DT3 corresponding to the luminance of the pixel of the image signal flows through the pixels in the third row, and this continues. Thereafter, as shown in the upper part of FIG. 9, when the data writing period D2 of the scanning signal of the fourth row starts (time t15), as shown in the middle part of FIG. 9, a value corresponding to the luminance of the pixel of the image signal DT4 is written in the pixels of the fourth row, and as shown in the lower part of FIG. 9, the light emitting elements of the pixels of the fourth row emit light at a luminance corresponding to the value DT4 corresponding to the luminance of the pixel of the image signal. Continue. That is, the driving current corresponding to the value DT4 corresponding to the luminance of the pixel of the image signal flows through the pixels in the second row, and this continues. Thereafter, the same operation is repeated up to the n-th row in one frame period.

  As a result, in the pixel matrix 10, the period from the start of the reference value writing period D1 of the second row scanning signal to the start of the data writing period D2 of the first row scanning signal (period from time t3 to time t5). The driving current corresponding to the reference value flows in the pixels in these two rows, and the driving current corresponding to the luminance of the pixel of the image signal flows in the pixels in the other rows. When the data writing period D2 of the scanning signal of the first row starts (time t5), the driving current corresponding to the reference value flows in the pixels of the second row, and the pixels of the image signal pass to the pixels of the other rows. A drive current corresponding to the luminance of the current flows. Then, when the data writing period D2 of the scanning signal of the second row starts (time t7), a driving current corresponding to the luminance of the pixel of the image signal flows in all the pixels. Then, when the reference value writing period D1 of the scanning signal of the third row starts, the same operation as described above is repeated in the next row group.

  Therefore, in the pixel matrix 10, the period from the start of the reference value writing period D1 of the second row scanning signal to the start of the data writing period D2 of the second row scanning signal (period from time t3 to time t7). In only the pixels in the first row of the row group, the value of the drive current flowing through these pixels changes from the value corresponding to the reference value to the value corresponding to the luminance of the pixel of the image signal. In the period from the start of the reference value writing period D1 of the second row scanning signal to the start of the reference value writing period D1 of the third row scanning signal (period from time t3 to time t9), In only the row group, that is, the pixels in the first row and the second row, the value of the drive current flowing through them changes from a value corresponding to the reference value to a value corresponding to the luminance of the pixel of the image signal.

  That is, when this is generalized, in the pixel matrix 10, the second row (here, the second row) of the certain row group after the start of the reference value writing period D1 of the scanning signal of the last row of the certain row group. In the period until the data writing period D2 of the scanning signal starts, only in the pixels of the first row of the row group, the value of the drive current flowing through these pixels is changed from the value corresponding to the reference value to the pixel of the image signal. It changes to a value corresponding to the brightness. In the period from the start of the reference value writing period D1 of the scanning signal of the last row of a certain row group to the start of the reference value writing period D1 of the scanning signal of the first row of the next row group, In only the pixels in all rows constituting a row group, the value of the drive current flowing through these pixels changes from the value corresponding to the reference value to the value corresponding to the luminance of the pixel of the image signal.

  Therefore, in the present embodiment, a certain row group after the reference value writing period D1 of the scanning signal of the last row (for example, second row) of the row group having the first current value acquisition timing (for example, TS1) starts. Is set so as to be positioned in a period (time t3 to time t5) until the reference value writing period D1 of the scanning signal of the first row (for example, the first row) starts, and the second current value acquisition timing (for example, TS2) is set. The reference value writing period D1 of the scanning signal of the first row (for example, the third row) of the next row group after the scanning signal data writing period D2 of the last row (for example, the second row) of a certain row group is started. It is set so as to be located in a period (time t7 to time t9) until the start. Thereby, it is possible to appropriately detect the difference between the drive current corresponding to the luminance of the pixel of the image signal and the drive current corresponding to the reference value in the pixels of all rows constituting the row group.

  By the way, in this embodiment, the difference between the current value acquired at the second current value acquisition timing and the current value acquired at the first current value acquisition timing is the drive in the pixels of all the rows constituting one row group. Since it represents the total value of the current change, it is necessary to divide these into the drive current changes in the pixels in each row. Therefore, in the present embodiment, the correction value calculation unit 153 performs the following calculation.

  Here, a case of a group of rows composed of the first row and the second row is illustrated. The reference value is a black value (luminance 0).

  A value (gate voltage) corresponding to the luminance of the pixel of the image signal of the data signal written to the pixel P1y in the first row (y represents an arbitrary column order) is represented by Vg1, and at this time, the pixel P1y is actually applied to the pixel P1y. Is represented by Id1, and the value corresponding to the luminance of the pixel of the image signal of the data signal written to the pixel P2y in the second row is represented by Vg2, and at this time, the pixel P2y A drive current that actually flows (not measurable alone) is represented by Id2, and the sum of Id1 and Id2 is represented by I. This current I is the difference between the current value acquired at the second current value acquisition timing and the current value acquired at the first current value acquisition timing, and is calculated by the correction value calculation unit 153 by the method described in the first embodiment. It is what is done.

  Further, the carrier mobility μ and the threshold voltage Vt, which are parameters of the driving transistor 321 of the pixel Pn1 at that time, are represented by μ1 and Vt1, respectively, and the carrier mobility μ and the threshold which are parameters of the driving transistor 321 of the pixel Pn2 at that time. The voltage Vt is represented by μ2 and Vt2, respectively. Further, it is assumed that these parameters have not changed significantly and the gate voltage-drain current characteristics of the drive transistors 321 of these pixels have not deteriorated significantly.

Then, when Vg1 and Vg2 are written in the pixel Pn1 in the first row and the pixel Pn2 in the second row, respectively, the driving currents assumed to flow in the pixel Pn1 in the first row and the pixel Pn2 in the second row, respectively. Are represented by Id1 ′ and Id2 ′, respectively.
Id1 ′ = (W / 2L) μ1Cox (Vgs1-Vt1) ^ 2
Id2 ′ = (W / 2L) μ2Cox (Vgs2-Vt2) ^ 2
It becomes.

Therefore, the difference between the assumed drive current and the drive current that actually flows (Id1-Id1 ') ^ 2+ (Id2-Id2') ^ 2
Id1 and Id2 can be calculated from I calculated by the correction value calculation unit 153 by distributing I to Id1 and Id2 so that is minimized. Here, the difference between the assumed drive current and the drive current that actually flows is due to changes in Vt and μ.

  Although the case where the reference value is a black value has been described above, the current I which is the sum of Id1 and Id2 is the current value acquired at the second current value acquisition timing and the first current value acquisition timing. Since it is a difference from the acquired current value, Id1 and Id2 can be calculated in exactly the same manner as described above even when the reference value has a predetermined luminance (gradation). Even when one row group includes three or more rows, Id1 and Id2 can be calculated in the same manner as described above.

  In the above description, the reference value writing period D1 is changed in the order of rows in the scanning signal group corresponding to one row group. However, the reference value writing period D1 is changed in the scanning signal group corresponding to one row group. You may set so that it may become simultaneous.

  As exemplified above, in the present invention, it is not always necessary to detect the difference in driving current for each pixel in one row, and the difference in driving current may be detected for each pixel in a plurality of rows.

(Embodiment 5)
FIG. 10 is a timing chart showing the acquisition timing of the current value used for correcting the data signal in the image display apparatus according to Embodiment 5 of the present invention.

  A waveform diagram of the vertical synchronizing signal is shown at the top of FIG. In the waveform diagram of the vertical synchronization signal, the vertical axis represents the signal level. The period (time t1 to time t4, time t11 to time t14...) During which the vertical synchronizing signal is at the LOW level is a vertical blanking period. In the vertical blanking period, the scanning signals of all the rows are included. There is no data writing period D1. That is, in the vertical blanking period, the data signal having a value corresponding to the luminance of the pixel of the image signal is not written in all the pixels of the pixel matrix 10. Further, one frame period is from the start of one vertical blanking period to the start of the next vertical blanking period.

  In the present embodiment, the values (DT1, DT2,...) Corresponding to the luminance of the pixels of the image signal in the data signal are the same as those in the conventional image display device for the pixels in the first to nth rows. Are sequentially written in the order of the rows. On the other hand, the reference values (RF1, RF2,...) In the data signal are written in the vertical blanking period. This reference value is written with a delay of one frame period in the order of the row groups for each scanning signal group corresponding to a row group consisting of a plurality of adjacent rows (here, two rows). In the scanning signal group corresponding to one row group, the reference value writing period D1 is set to be simultaneous.

  Then, the first current value acquisition timing corresponding to the pixel in the first row of a certain row group is located in the period from the start of the reference value writing period D1 to the start of the data writing period D2 in the scanning signal of the first row. The second current value acquisition timing corresponding to the pixel of the first row is set from the start of the data writing period D2 in the scanning signal of the first row to the start of the data writing period D2 of the next row of the certain row group. It is set to be located in the period. Taking the first row and the second row as an example, the first current value acquisition timing TS1 corresponding to the pixel in the first row of the row group consisting of the first row and the second row is the reference in the scanning signal of the first row. The second current value acquisition timing TS2 corresponding to the pixels in the first row is set to be positioned in a period (a period from time T2 to time t6) from the start of the value writing period D1 to the start of the data writing period D2. It is set to be located in a period (time t6 to time 8) from the start of the data write period D2 to the start of the second line data write period D2 in the row scanning signal. As a result, during the period from the first current value acquisition timing TS1 to the second current value acquisition timing TS2, in the pixel matrix 10, only the drive current of the pixels in the first row (first row) of a certain row group is the reference. The current value corresponding to the value changes from the current value corresponding to the luminance of the pixel of the image signal. Therefore, the difference between the drive current corresponding to the luminance of the pixel of the image signal and the drive current corresponding to the reference value can be detected for the pixels in the first row (first row) of a row group.

  In addition, the first current value acquisition timing corresponding to the pixel in the next row in the row group is set to be the same as the second current value acquisition timing corresponding to the pixel in the first row described above. That is, the second current value acquisition timing corresponding to the pixel in the first row also serves as the first current value acquisition timing corresponding to the pixel in the next row. Then, the second current value acquisition timing corresponding to the pixel of the next row is the data in the scanning signal of the first row of the next row group of the row group from the start of the data writing period D2 in the scanning signal of the next row. It is set so as to be located in the period until the start of the writing period D2. Taking the first to third rows as an example, the first current value acquisition timing corresponding to the pixels of the second row in the row group consisting of the first row and the second row corresponds to the pixels of the first row. It is set to be the same as the second current value acquisition timing. That is, the second current value acquisition timing TS2 corresponding to the pixels in the first row also serves as the first current value acquisition timing corresponding to the pixels in the second row. Then, the second current value acquisition timing TS3 corresponding to the pixels in the second row is scanned in the third row of the row group including the third row and the fourth row from the start of the data writing period D2 in the scanning signal of the second row. The signal is set so as to be positioned in a period (time t8 to t10) until the start of the data writing period D2. Thereby, during the period from the first current value acquisition timing TS2 to the second current value acquisition timing TS3, in the pixel matrix 10, only the drive current of the pixel in the next row (second row) of a certain row group is the reference. The current value corresponding to the value changes from the current value corresponding to the luminance of the pixel of the image signal. Therefore, the difference between the drive current corresponding to the luminance of the pixel of the image signal and the drive current corresponding to the reference value can be detected for the pixel in the next row (second row) of a row group.

  As described above, in this embodiment, the reference value is written in the vertical blanking period, and the reference value is written in the scanning signal group corresponding to the row group over a plurality of frame periods. Except for this, it is almost the same as the first embodiment.

  Therefore, even with such a configuration, the same effect as in the first embodiment can be obtained. Further, with such a configuration, a so-called data writing period can be made longer than that in the fourth embodiment.

  In the above description, one row group is composed of two rows, but one row group may be composed of one row (that is, every one row) or three or more rows.

(Summary of Embodiments 1 to 5)
In the first to fifth embodiments described above, examples of the configuration relating to the characteristic correction of the drive active element (driving transistor 321), which characterizes the present invention, have been described individually. The requirements for the configuration relating to the correction of the element characteristics will be described. Hereinafter, as described in the fourth embodiment, in order to simplify the description, the concept of the row group is used instead of the concept of the scanning line group.

  This requirement includes a requirement to write a value corresponding to the luminance of the pixel of the image signal and a reference value (hereinafter referred to as a write requirement), and a requirement for obtaining a total current of driving currents of light emitting elements for each line (here, a column) ( Hereinafter, it is broadly divided into “current acquisition requirements”.

  The write requirement includes the following three requirements.

  a. The value corresponding to the luminance of the pixel of the image signal is written to the pixels belonging to all the rows in accordance with a certain order (hereinafter referred to as the data writing order) in a row unit so that the data writing period does not overlap between the rows. It is.

  This requirement is also a requirement required in the conventional image display apparatus. Otherwise, in each column, a value corresponding to the luminance of the pixel of the image signal cannot be written to the intended pixel.

  b. The reference value is written before the value corresponding to the luminance of the pixel of the image signal in each row group.

  c. The reference value is written according to the data writing order for each group of one or more rows that are adjacent (adjacent) in the data writing order. The reference value writing period may overlap between rows belonging to the same row group, but does not overlap between rows belonging to different row groups.

  By satisfying the requirements of b and c, in the pixel matrix, the driving current of the light emitting element changes from the value corresponding to the reference value to the value corresponding to the luminance of the pixel of the image signal only in the pixels belonging to the rows of each row group. In a pixel belonging to a row in a row group other than the row group, a period during which the drive current of the light emitting element having a value corresponding to the luminance of the pixel of the image signal flows (and does not change) (hereinafter referred to as a drive current difference detectable period) ) Always exists.

  The current acquisition requirements are as follows.

  d. The sum of the drive currents of the light emitting elements in a column in the period from the start of the reference value writing period of the last row in the data writing order of a row group to the start of the data writing period of the first row in the data writing order of the row group From the start of the data write period of the first row in the data write order of the row group to the reference value write period of the first row in the data write order of the next row group in the data write order of the row group A difference from the total current value of the drive currents of the light emitting elements in the column in the period is calculated.

  Thereby, at least the difference between the drive current corresponding to the value corresponding to the luminance of the pixel of the image signal and the drive current corresponding to the reference value is calculated for each pixel in all rows of each row group. This difference is distributed using, for example, a value corresponding to the luminance of the pixel of the image signal in the pixel of each row constituting the row group, thereby corresponding to the luminance of the pixel of the image signal in the pixel of each row constituting the row group. The difference between the drive current corresponding to the value to be driven and the drive current corresponding to the reference value can be calculated.

  As described above, the present invention is configured to satisfy the above write requirement and current acquisition requirement, so that the drive current corresponding to the value corresponding to the luminance of the pixel of the image signal in the pixel of each row and the drive corresponding to the reference value. The difference with the current can be calculated, and accordingly, the luminance unevenness caused by the non-uniformity of the characteristics of the drive active element can be corrected based on the calculated difference.

  In the first to fifth embodiments, the value corresponding to the luminance of the pixel of the image signal is written according to the order of the rows (descending order). However, the present invention is not limited to this. You may make it write in an even-numbered line after.

(Embodiment 6)
FIG. 11 is a block diagram showing an electrical configuration of an image display apparatus according to Embodiment 6 of the present invention.

  As shown in FIG. 11, in the present embodiment, the image display device 170 includes two current extraction power sources, a first current extraction power source 704 and a second current extraction power source 705. The output terminal of the first current extraction power supply 704 is connected to the first common current extraction line 23-0A through the current measuring element 703, and the second common current extraction line 23-0B is connected to the output terminal of the second current extraction power supply 705. It is connected. The first current extraction power supply 704 and the second current extraction power supply 705 output the same potential to the first common current extraction line 23-0A and the second current extraction line 23-0B, respectively. Then, the switch circuit 700 selectively connects the m current lead lines 23-1 to 23-m to the first common current lead line 23-0A and the second common current lead line 23-0B, respectively. This selective connection is performed under the control of the control unit 151. A current measuring element 703 is connected to the downstream end of the first common current lead line 23-0A. This current measuring element 703 is configured in the same manner as the current measuring elements 24-1 to 24-m of the first embodiment. The current value measured by the current measuring element 703 is sent to the correction value calculation unit 153, and the correction value calculation unit 153 sends the current value to the predetermined area of the correction value memory 160 in the current lead lines 23-1 to 23-m (or pixels). The data are stored in correspondence with the columns of the matrix 10. The current values corresponding to the respective current lead lines 23-1 to 23-m are stored so as to be sequentially updated with new current values.

  The switch circuit 700 controls the m current lead lines 23-1 to 23-m and one current lead line among the m current lead lines 23-1 to 23-m under the control of the control unit 151. The first common current lead line 23-0A and the remaining current lead lines are connected to the second common current lead line 23-0B so that the first common current lead lines 23-0A and Connected to the first common current lead line 23-0A.

  Thereby, the current values of the m current lead lines 23-1 to 23 -m are sequentially and independently measured by the current measuring element 703 and stored in the correction value memory 160 via the correction value calculation unit 153. . The correction value calculation unit 153 reads the current value temporarily stored in the correction value memory 160 and calculates the correction value (μ, Vt) of the gate voltage-drain current characteristic of the driving transistor 321 described in the first embodiment. . The other points are the same as in the first embodiment.

  Note that a reference value data signal is not written to a pixel connected to a current lead line that is not measured (not connected to the first common current lead line 23-0A by the switch circuit 700). Also good.

  According to the present embodiment configured as described above, the number of current measuring elements can be reduced to one.

(Embodiment 7)
FIG. 12 is a block diagram showing an electrical configuration of an image display apparatus according to Embodiment 7 of the present invention. The present embodiment shows a modification of the arrangement position of the current measuring element. The basic configuration of the present embodiment is the same as that of the first embodiment, but the following points are different.

  As shown in FIG. 12, in the present embodiment, m current measuring elements 24-1 to 24-m are provided in m current supply lines 22-1 to 22-m, respectively. In addition, the current leader line is not formed, and instead, the light emitting elements 323 (see FIG. 2) of all the pixels P11 to Pnm are formed so as to share one common cathode 50. The common cathode 50 is connected to a current extraction power source 130 (see FIG. 1) (not shown).

  The other points are the same as in the first embodiment.

  With such a configuration, the current leader line can be omitted, so that the configuration of the image display device can be simplified.

  The image display apparatus and the driving method thereof according to the present invention is a current-driven type capable of correcting the luminance unevenness caused by the non-uniformity of the characteristics of the driving active element by measuring the driving current of the light emitting element selected during the image display. It is useful as an image display device using a light emitting element and a driving method thereof.

1 is a block diagram showing an electrical configuration of an image display apparatus according to Embodiment 1 of the present invention. FIG. 2 is a circuit diagram illustrating a configuration of a pixel circuit of the image display device in FIG. 1. It is a circuit diagram which shows the structure of the current measurement element of the image display apparatus of FIG. It is a timing chart which shows the acquisition timing of the electric current value used for correction | amendment of a data signal. It is a graph which shows the gate voltage-drain current characteristic of a driving transistor. It is a circuit diagram which shows the structure of the modification in the switch transistor and driving transistor of a pixel. It is a timing chart which shows the acquisition timing of the electric current value used for correction | amendment of the data signal in the image display apparatus which concerns on Embodiment 2 of this invention. It is a timing chart which shows the acquisition timing of the electric current value used for correction | amendment of the data signal in the image display apparatus which concerns on Embodiment 3 of this invention. It is a timing chart which shows the acquisition timing of the electric current value used for correction | amendment of the data signal in the image display apparatus which concerns on Embodiment 4 of this invention. It is a timing chart which shows the acquisition timing of the electric current value used for correction | amendment of the data signal in the image display apparatus which concerns on Embodiment 5 of this invention. It is a block diagram which shows the electric constitution of the image display apparatus which concerns on Embodiment 6 of this invention. It is a block diagram which shows the electric constitution of the image display apparatus which concerns on Embodiment 7 of this invention.

Explanation of symbols

10 pixel matrix 20-1 to 20-n scanning line 21-1 to 21-m data line 22-0 common current supply line 22-1 to 22-m current supply line 23-0 common current lead line 23-0A first Common current lead line 23-0B Second common current lead line 23-1 to 23-m Current lead line 24-1 to 24-m, 703 Current measuring element 30 Controller 40 Voltage sensor 41 A / D converter 50 Common cathode DESCRIPTION OF SYMBOLS 100 Scan line drive circuit 110 Data line drive circuit 120 Current supply power supply 130 Current extraction power supply 140 Current memory 150 Calculation part 151 Control part 152 Write part 153 Correction value calculation part 160 Correction value memory 170 Image display apparatus 300 Pixel circuit 320, 330 Switching Transistor 321, 331 Driving transistor 322 Capacitor 323 Light emitting element 24, a drive current path 700 switch circuit 701 latches 702 shift register 704 first current extraction power supply 705 second current extraction power supply D1 reference value writing period D2 data write period P11~Pnm pixel R resistor T0, T1, T2 predetermined period

Claims (14)

A pixel matrix in which a plurality of pixels are arranged on the matrix;
A plurality of scanning lines provided corresponding to one of the rows and columns of the pixel matrix (hereinafter referred to as one line);
A plurality of data lines provided corresponding to the other of the rows and columns of the pixel matrix (hereinafter referred to as the other line), a drive current path provided in the pixel and through which a drive current flows;
A light emitting element that is provided on the drive current path and emits light at a luminance corresponding to the drive current;
A drive active element that is provided on the drive current path and controls the drive current according to a value of a data signal;
Each of the pixels is connected to the scanning line corresponding to the pixel, and the transmission path of the data signal (hereinafter referred to as data) to the driving active element in response to the input and stop of the selection signal from the scanning line. A switching element that opens and closes the signal transmission path);
A scanning line driving circuit that sequentially outputs the selection signal to the plurality of scanning lines over a data writing period;
A data line driving circuit for outputting a corresponding data signal to each of the plurality of data lines in accordance with the sequential output of the selection signal to the plurality of scanning lines by the scanning line driving circuit;
Provided corresponding to the other line of the pixel matrix, the drive current flows into the drive current paths of all the pixels belonging to each other line, or flows out from the drive current paths of all the pixels belonging to each other line. A plurality of current lines through which drive current flows;
A current measuring element for measuring the current of each current line;
A current memory for storing a current value of each of the current lines measured by the current measuring element;
Correction value calculating means for calculating a correction value of the value of the data signal using a current value stored in the current memory;
A correction value memory for storing the correction value calculated by the correction value calculating means;
A writing means for converting an image signal input from the outside into the data signal corresponding to the plurality of scanning lines using a correction value stored in the correction value memory, and outputting the data signal to the data line driving circuit; With
The scanning line driving circuit is further configured to sequentially output the selection signal over a reference value writing period before the data writing period for each scanning line group including one or more scanning lines. ,
The writing unit is configured to generate the data signal having a reference value and a value corresponding to a luminance of a pixel of the input image signal and output the data signal to the data line driving circuit.
The data line driving circuit corresponds to each of the plurality of data lines in accordance with the output of the selection signal over the reference value writing period and the data writing period to the plurality of scanning lines by the scanning line driving circuit. It is configured to output a data signal having a value corresponding to the reference value and luminance of a pixel of the image signal,
The correction value calculating means outputs the selection signal corresponding to the reference value writing period in the last scanning line of the certain scanning line group for each data line, in the first scanning line of the certain scanning line group. The current value stored in the current memory of the corresponding current line in the period until the selection signal corresponding to the data writing period is output, and the data writing period in the first scanning line of the certain scanning line group The corresponding current line in the period from when the selection signal to be output to when the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the certain scanning line group. An image display device configured to calculate a difference from a current value stored in a current memory and calculate the correction value based on the calculated difference.   The image display apparatus according to claim 1, wherein the number of scanning lines constituting the scanning line group is one.   The image display apparatus according to claim 1, wherein the number of scanning lines constituting the scanning line group is two. The correction value calculation means outputs, for each data line, a selection signal corresponding to the data writing period after a selection signal corresponding to the reference value writing period is output on the last scanning line of the certain scanning line group. A current value stored in the current memory of the corresponding current line in a period until a predetermined time and a selection signal corresponding to the data write period in the last scanning line of the certain scanning line group after the output of the selection signal The difference between the current value stored in the current memory of the corresponding current line in the period until the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the line group To calculate
By distributing the difference using the value corresponding to the luminance of the pixel of the image signal in the pixel of the row corresponding to each scanning line constituting the scanning line group, each scanning line constituting the scanning line group is distributed to each scanning line constituting the scanning line group. 2. The image according to claim 1, configured to calculate a difference between a driving current corresponding to a value corresponding to a luminance of a pixel of the image signal in a corresponding row of pixels and a driving current corresponding to the reference value. Display device.   The image display apparatus according to claim 1, wherein the scanning line driving circuit is configured to output the selection signal so that the reference value writing period is positioned in a vertical blanking period of a vertical synchronization signal.   The scanning line driving circuit is configured to output the selection signal over the reference value writing period so as to be delayed by one or more frame periods in order for each scanning line group. The image display device described.   One current measuring element and a switch circuit for sequentially and selectively connecting the plurality of current lines to the current measuring element, and the current memory stores a current value measured by the current measuring element in each current line. The image display device according to claim 1, wherein the image display device is configured to store the information in correspondence with each other. A pixel matrix in which a plurality of pixels are arranged on the matrix;
A plurality of scanning lines provided corresponding to one of the rows and columns of the pixel matrix (hereinafter referred to as one line);
A plurality of data lines provided corresponding to the other of the rows and columns of the pixel matrix (hereinafter referred to as the other line), a drive current path provided in the pixel and through which a drive current flows;
A light emitting element that is provided on the drive current path and emits light at a luminance corresponding to the drive current;
A drive active element that is provided on the drive current path and controls the drive current according to a value of a data signal;
Each of the pixels is connected to the scanning line corresponding to the pixel, and the transmission path of the data signal (hereinafter referred to as data) to the driving active element in response to the input and stop of the selection signal from the scanning line. A switching element that opens and closes the signal transmission path);
A scanning line driving circuit that sequentially outputs the selection signal to the plurality of scanning lines over a data writing period;
A data line driving circuit for outputting a corresponding data signal to each of the plurality of data lines in accordance with the sequential output of the selection signal to the plurality of scanning lines by the scanning line driving circuit;
Provided corresponding to the other line of the pixel matrix, the drive current flows into the drive current paths of all the pixels belonging to each other line, or flows out from the drive current paths of all the pixels belonging to each other line. A plurality of current lines through which drive current flows;
A current measuring element for measuring the current of each current line;
A current memory for storing a current value of each of the current lines measured by the current measuring element;
Correction value calculating means for calculating a correction value of the value of the data signal using a current value stored in the current memory;
A correction value memory for storing the correction value calculated by the correction value calculating means;
A writing means for converting an image signal input from the outside into the data signal corresponding to the plurality of scanning lines using a correction value stored in the correction value memory, and outputting the data signal to the data line driving circuit; A method for driving an image display device comprising:
The scanning line driving circuit further outputs the selection signal over a reference value writing period prior to the data writing period for each scanning line group including one or more scanning lines.
The writing unit generates the data signal having a reference value and a value corresponding to a luminance of a pixel of the input image signal, and outputs the data signal to the data line driving circuit.
The data line driving circuit corresponds to each of the plurality of data lines in accordance with the output of the selection signal over the reference value writing period and the data writing period to the plurality of scanning lines by the scanning line driving circuit. Outputting a data signal having a value corresponding to a luminance of the pixel of the reference value and the image signal;
The correction value calculating means outputs the selection signal corresponding to the reference value writing period in the last scanning line of the certain scanning line group for each data line, in the first scanning line of the certain scanning line group. The current value stored in the current memory of the corresponding current line in the period until the selection signal corresponding to the data writing period is output, and the data writing period in the first scanning line of the certain scanning line group The corresponding current line in the period from when the selection signal to be output to when the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the certain scanning line group. A method for driving an image display device, wherein a difference from a current value stored in a current memory is calculated, and the correction value is calculated based on the calculated difference.   The method for driving an image display device according to claim 8, wherein the number of scanning lines constituting the scanning line group is one.   The method for driving an image display device according to claim 8, wherein the number of scanning lines constituting the scanning line group is two. The correction value calculating means outputs, for each data line, the first scanning line of the certain scanning line group after the selection signal corresponding to the reference value writing period is output in the last scanning line of the certain scanning line group. The current value stored in the current memory of the corresponding current line in the period until the selection signal corresponding to the data writing period is output, and the data writing period in the last scanning line of the certain scanning line group The corresponding current line in the period from when the selection signal to be output to when the selection signal corresponding to the reference value writing period is output in the first scanning line of the next scanning line group of the certain scanning line group. Calculate the difference from the current value stored in the current memory,
By distributing the difference using the value corresponding to the luminance of the pixel of the image signal in the pixel of the row corresponding to each scanning line constituting the scanning line group, each scanning line constituting the scanning line group is distributed to each scanning line constituting the scanning line group. 9. The driving method for an image display device according to claim 8, wherein a difference between a driving current corresponding to a value corresponding to a luminance of a pixel of the image signal in a pixel in a corresponding row and a driving current corresponding to the reference value is calculated. .   The method of driving an image display device according to claim 8, wherein the scanning line driving circuit outputs the selection signal so that the reference value writing period is positioned in a vertical blanking period of a vertical synchronization signal.   9. The image display device according to claim 8, wherein the scanning line driving circuit outputs the selection signal over the reference value writing period so as to be delayed by one or more frame periods in order for each scanning line group. Driving method.   One current measuring element and a switch circuit for sequentially and selectively connecting the plurality of current lines to the current measuring element, and the current memory stores a current value measured by the current measuring element in each current line. The image display device driving method according to claim 8, wherein the image display device is stored in correspondence with the image data.

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