JP5280291B2 - Organic EL active matrix driving method, driving circuit, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for driving an organic EL active matrix, which always compensates for characteristic variation of an amorphous silicon TFT and an organic EL element, while accurately measuring current-voltage measurement characteristics and interpolating a coefficient for each pixel with high reliability, and to provide a driving circuit and a display device. <P>SOLUTION: A matrix display panel is divided into m&times;n blocks. IV characteristic measurement in S201 is performed for at least three or more points so that &radic;IdV characteristics are approximated by primary expression: &radic;ID=AVg+Bi in one block. Since expected current is no longer obtained by three voltages when time passes, it is necessary to properly change the voltages to Vg1n-Vg3n. In S202, the IdV characteristics measured in S201 is changed to the &radic;IdV characteristics, and a primary expression of the &radic;IdV characteristics is calculated. In S203, a coefficient An and offset Bn of the primary expression are stored in a corrected data storage circuit 25. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an organic EL active matrix driving method, a driving circuit, and a display device, and more specifically, a self-luminous display panel such as an EL display panel (display device) using an organic or inorganic electroluminescence (EL) element. The present invention relates to a (display device) driving method, a driving circuit, and a display device.

  In an active matrix image display device using an organic electroluminescence (EL) material or an inorganic EL material as an electro-optic conversion substance, light emission luminance changes according to a current written to a pixel. The EL display panel is a self-luminous type having a light emitting element in each pixel. The EL display panel has advantages such as higher image visibility, higher light emission efficiency, no backlight, and faster response speed than the liquid crystal display panel.

  FIG. 18 shows an equivalent circuit of one pixel in a conventional active matrix type organic EL display panel. The pixel circuit 10 includes an organic EL element 11 as a light emitting element, a first transistor (Thin Film Transistor) 12, a second transistor (Thin Film Transistor) 13, and a storage capacitor C14.

  The source driver 17 for driving the pixel circuit 10 outputs a video (grayscale signal) indicated by the strength of the voltage and has a similar configuration to the driver circuit for driving the liquid crystal display panel. A voltage signal as a video (gradation) signal is applied from the source driver 17 to the source signal line 15. The applied voltage signal is applied to the pixel circuit 10 and held at C14. A current Id corresponding to the voltage held by the capacitor C14 flows, and the organic EL element 11 emits light with a predetermined luminance.

The gate driver 18 is for the purpose of storing the image (tone) signal on a line-by-line basis, specifically, continue to on the TFT13 of each row in turn.

JP 2006-284716 A JP 2004-101767 A JP 2007-011205 A JP 2001-350442 A Japanese Patent Laying-Open No. 2005-070614

  The organic EL display panel is configured by using low-temperature polysilicon or amorphous TFT. However, when the characteristics of these TFTs vary in the organic EL element, display (brightness) unevenness occurs.

  In particular, in the case of an amorphous TFT, the threshold voltage Vth rises and varies with time with the energization time. At the same time, the voltage of the organic EL element also rises and changes. Due to these fluctuations, the current-voltage characteristic (IV characteristic: in FIG. 19, the current Id is set to √Id for linear expression) is a threshold voltage Vth ( Vthi to Vthn) and the slope coefficient A (Ai to An) are different. When the voltage of the organic EL element fluctuates, since the power supply voltage is constant, the voltage Vds between the drain and the source of the TFT also fluctuates, so that the drive current Id changes. Due to these fluctuations, when the initial gradation voltage Vgi is applied, the current gradually decreases and the emission luminance decreases.

  In order to solve this problem, a method is disclosed in which after changing Vth is read by AD conversion or the like, it is temporarily stored and added to the gradation voltage Vdata to be displayed, and the corrected display voltage Vdisp is given to the pixel circuit 10. (See Patent Document 1). However, this method cannot suppress fluctuations in drive current that accompany voltage fluctuations in the organic EL element.

  Further, there is disclosed a method for correcting the characteristic variation for each pixel, which is similar to the above-described temporal variation of the voltage of Vth and the organic EL element (see Patent Document 2). However, in this method, there is a problem that it is necessary to temporarily stop the display operation and execute the correction operation in order to compensate for the characteristic that is constantly fluctuating, and is not practical.

Transition performed when the power supply voltage measurement is judged to have a transition from ON to OFF, ON powered from off - from such problems, current - for voltage measurement to reduce the effect on the normal display processing, the current There is a method of performing a normal display process when it is determined that it has been performed (see Patent Document 3) and a method of reducing the influence on the normal display process by performing a current value measurement during a blanking period existing in the video signal. (See Patent Document 4).

  Further, by estimating the current value of each pixel from the current value of the first group and the current value of the second group, the current value to be measured is greatly reduced, and the time required for current-voltage measurement is shortened. There is a method of reducing the influence on normal display processing (see Patent Document 5).

However, even if these methods are used, there are problems such as that it takes a very long time for display to start and that the accuracy of current-voltage measurement is insufficient.

  The present invention has been made in view of such problems, and the object of the present invention is to make it possible to always compensate for characteristic fluctuations of the amorphous silicon TFT and the organic EL element, and to measure current-voltage measurement characteristics with high accuracy. Another object of the present invention is to provide an organic EL active matrix driving method, a driving circuit, and a display device capable of performing both pixel interpolation coefficient calculations with high reliability.

In order to solve the above-mentioned problem, the invention described in claim 1 is a method for driving an organic EL active matrix, in a display device having an organic EL element and an amorphous Si-TFT and forming a matrix. Dividing the screen of the display device into m × n (m, n: a positive integer) in units of a block of a predetermined number of pixels, and a first current-voltage characteristic for each of the divided blocks. A first measuring step for measuring in order, and a second measuring step for sequentially measuring a second current-voltage characteristic for each of the divided blocks at a predetermined time interval from the first measuring step. And a gradation voltage signal, which is display data for providing a predetermined gradation current signal based on the first current-voltage characteristic, and the gradation voltage signal based on the second current-voltage characteristic. To provide et predetermined gradation current signal, the first and second current - possess and correcting the gradation voltage signal from the voltage characteristic, a step of correcting, the first and First and second linear expressions representing the relationship between the square root of the current and the voltage are calculated from the second current-voltage characteristics, and the slope coefficient and offset of the first and second linear expressions are used to calculate the first and second linear expressions. A step of correcting the gradation voltage signal, and a slope coefficient of the pixels between the center pixels arranged in the one side, wherein the slope coefficient between the center pixels adjacent to one of the column direction and the row direction and the first difference of the offset are arranged on the one side And the second difference of the slope coefficient and the offset between the central pixel adjacent to the other of the other of the vertical direction and the horizontal direction and the first difference of the proportionally distributed pixels are arranged on the other side. The center pixel and the first difference are proportionally distributed to the slope coefficient and offset of the pixel between the proportionally distributed pixels, and the slope coefficient and offset of the first and second linear equations are corrected for each pixel. And correcting the gradation voltage signal for each pixel using the corrected slope coefficients and offsets of the first and second linear equations .

The invention according to claim 2 is a driving method of an organic EL active matrix, in a display device having an organic EL element and an amorphous Si-TFT and forming a matrix.
Dividing the screen of the display device into m × n (m, n: a positive integer) in units of a block of a predetermined number of pixels, and a first current-voltage characteristic for each of the divided blocks. A first measuring step for measuring in order, and a second measuring step for sequentially measuring a second current-voltage characteristic for each of the divided blocks at a predetermined time interval from the first measuring step. And a gradation voltage signal, which is display data for providing a predetermined gradation current signal based on the first current-voltage characteristic, from the gradation voltage signal based on the second current-voltage characteristic. Correcting the grayscale voltage signal from the first and second current-voltage characteristics so as to provide the grayscale current signal, wherein the correcting step includes the steps of: From the current-voltage characteristics A step of calculating a first and second linear equation representing the relationship between the square root of the voltage, to correct the gradation voltage signal using the first and second primary type inclination coefficient and offset of The block has a region that overlaps with a block adjacent to one or both of the vertical and horizontal directions, and each block is assigned a predetermined weighting factor proportional to the distance from the center. The slope coefficient and offset of the first and second linear expressions for each pixel in the overlapped area, and the slope coefficient and offset of the first and second linear expressions for each block for each pixel of the block. And adding the ratio of the weighting factors assigned to the grayscale voltage signal using the interpolated slope coefficients and offsets of the first and second linear equations. Correcting the signal for each pixel .

According to a third aspect of the present invention, in the method for driving an organic EL active matrix according to the first or second aspect , the measuring step includes controlling the source driver and the gate driver in an integrated manner so that an arbitrary pixel of the display device is obtained. A voltage is simultaneously written to the group, and a current-voltage characteristic for each block is measured.

According to a fourth aspect of the present invention, in the organic EL active matrix driving method according to any one of the first to third aspects of the present invention, the step of measuring is performed for each block after the display device is turned off (black display). Measuring at least three current-voltage characteristics, and the step of correcting includes calculating a slope coefficient and an offset of the linear equation and storing them in a storage device.

According to a fifth aspect of the present invention, in the organic EL active matrix driving method according to any one of the first to fourth aspects, the power supply is turned on or off when the display device does not perform normal display processing. The step of measuring is performed.

According to a sixth aspect of the present invention, in the organic EL active matrix driving method according to any one of the first to fourth aspects, a period during which display is stopped for each screen that is a display cycle of the display device is set to one row or One horizontal time or more is provided, and current-voltage characteristics of one block are measured during the display stop period.

According to a seventh aspect of the present invention, in the method for driving an organic EL active matrix according to any one of the first to fourth aspects, a predetermined period for stopping display is provided for each screen that is a display cycle of the display device. The measurement of the current-voltage characteristic of one block is performed during the display stop period over a plurality of cycles.

The invention according to claim 8 is an organic EL active matrix driving circuit for driving a display device having an organic EL element and an amorphous Si-TFT and forming a matrix, wherein the screen of the display device is a predetermined circuit. A current-voltage measurement circuit that divides a block of a plurality of pixels into m × n (m, n: a positive integer) and measures the current-voltage characteristics of each of the divided blocks in order. A correction data storage circuit for storing the current-voltage characteristics, and a gradation voltage signal which is display data for providing a predetermined gradation current signal based on the first current-voltage characteristics stored in the correction data storage circuit. And applying the predetermined grayscale current signal from the grayscale voltage signal based on a second current-voltage characteristic measured at a predetermined time interval from the first current-voltage characteristic. Serial first and second current - a correction arithmetic unit for correcting the gradation voltage signal from the voltage characteristic, the first and second current - first representing the relationship between the square root and the voltage of the current voltage characteristics The first and second linear equations are calculated, the grayscale voltage signal is corrected using the slope coefficients and offsets of the first and second linear equations, and adjacent to one of the column direction and the row direction. The central pixel adjacent to the other of the vertical direction and the horizontal direction is distributed proportionally to the inclination coefficient and the offset of the pixel between the central pixels arranged in one of the first difference between the central pixel and the inclination coefficient between the central pixels And the slope of the pixel between the center pixel arranged on the other side and the pixel on which the first difference is proportionally distributed, and the second difference of the slope coefficient and offset between the pixels to which the first difference is proportionally distributed Coefficient and A correction calculator that corrects the slope coefficients and offsets of the first and second linear equations for each pixel by proportionally allocating to the offset; and a column of the display device based on the corrected gradation voltage signal A source driver having a DA conversion array for controlling a direction; and a gate driver having an output circuit for controlling a row direction of the display device, wherein the source driver and the gate driver are integrated and controlled. A voltage can be simultaneously written to any of the pixel groups.
The invention according to claim 9 is an organic EL active matrix driving circuit for driving a display device having an organic EL element and an amorphous Si-TFT and forming a matrix, wherein the screen of the display device is a predetermined circuit. A current-voltage measurement circuit that divides a block of a plurality of pixels into m × n (m, n: a positive integer) and measures the current-voltage characteristics of each of the divided blocks in order. A correction data storage circuit for storing the current-voltage characteristics, and a gradation voltage signal which is display data for providing a predetermined gradation current signal based on the first current-voltage characteristics stored in the correction data storage circuit. And applying the predetermined grayscale current signal from the grayscale voltage signal based on a second current-voltage characteristic measured at a predetermined time interval from the first current-voltage characteristic. A correction arithmetic unit that corrects the gradation voltage signal from the first and second current-voltage characteristics, wherein the first and second current-voltage characteristics represent a relationship between the square root of the current and the voltage. The first and second linear equations are calculated, the gradation voltage signal is corrected using the slope coefficients and offsets of the first and second linear equations, and the block is either in the vertical or horizontal direction. Or a block that overlaps with both adjacent blocks, and each block is assigned a predetermined weighting factor that is proportional to the distance from the center to each block, and the first and each of the pixels in the overlapping region of the block The slope coefficient and offset of the second primary expression are added to the ratio of the weight coefficient assigned to each pixel of the block by the slope coefficient and offset of the first and second primary expressions for each block. Together A source driver comprising a correction computing unit and a DA conversion array for controlling the column direction of the display device based on the corrected gradation voltage signal, and controlling the row direction of the display device And a gate driver having an output circuit for controlling the source driver and the gate driver, and simultaneously writing a voltage to an arbitrary pixel group of the display device.

The invention according to claim 10 is an organic EL active matrix display device, comprising a display panel having an organic EL element and an amorphous Si-TFT and forming a matrix, and a predetermined number of screens of the display device. A current-voltage measurement circuit that measures the current-voltage characteristics of each of the divided blocks in order, divided into m × n (m, n: a positive integer) in units of blocks each including the pixels, and the measured current A correction data storage circuit that stores voltage characteristics, and a gradation voltage signal that is display data that provides a predetermined gradation current signal based on the first current-voltage characteristics stored in the correction data storage circuit, The predetermined gradation current signal is applied from the gradation voltage signal based on a second current-voltage characteristic measured at a predetermined time interval from the first current-voltage characteristic. 1 and the second current - a correction arithmetic unit for correcting the gradation voltage signal from the voltage characteristic, the first and second current - first and representing the relationship between the square root and the voltage of the current voltage characteristics A central pixel adjacent to one of the column direction and the row direction is calculated by calculating a second linear expression and correcting the gradation voltage signal using the slope coefficient and offset of the first and second linear expressions. A first difference in slope coefficient and offset between the center pixels arranged in one of the pixels, and the center pixel adjacent to the other in the vertical direction and the horizontal direction, A slope coefficient between pixels proportionally distributed with a first difference and a second slope difference between the central pixel arranged on the other side and a slope coefficient of pixels between pixels proportionally distributed with the first difference; off A correction calculator for correcting the slope coefficients and offsets of the first and second linear equations for each pixel in proportion to the set; and a column of the display device based on the corrected gradation voltage signal A source driver having a DA conversion array for controlling a direction; and a gate driver having an output circuit for controlling a row direction of the display device, wherein the source driver and the gate driver are integrated and controlled. A voltage can be simultaneously written to any of the pixel groups.
The invention according to claim 11 is an organic EL active matrix display device, comprising a display panel having an organic EL element and an amorphous Si-TFT and forming a matrix, and a predetermined number of screens of the display device. A current-voltage measurement circuit that measures the current-voltage characteristics of each of the divided blocks in order, divided into m × n (m, n: a positive integer) in units of blocks each including the pixels, and the measured current A correction data storage circuit that stores voltage characteristics, and a gradation voltage signal that is display data that provides a predetermined gradation current signal based on the first current-voltage characteristics stored in the correction data storage circuit, The predetermined gradation current signal is applied from the gradation voltage signal based on a second current-voltage characteristic measured at a predetermined time interval from the first current-voltage characteristic. A correction calculator for correcting the grayscale voltage signal from the first and second current-voltage characteristics, wherein the first and second current-voltage characteristics indicate a relationship between a square root of current and a voltage. A second linear expression is calculated, the gradation voltage signal is corrected using the slope coefficient and offset of the first and second linear expressions, and the block is either or both of the vertical and horizontal directions. A predetermined weighting factor proportional to the distance from the center is assigned to each pixel, and the first and second pixels for each pixel in the overlapping area of the block are assigned to each block. The slope coefficient and offset of the linear expression are added to the slope coefficient and offset of the first and second linear expressions for each block by the ratio of the weighting factor assigned to each pixel of the block. A source driver including a correction computing unit and a DA conversion array that controls the column direction of the display device based on the corrected gradation voltage signal, and controls the row direction of the display device. A gate driver including an output circuit is provided, and the source driver and the gate driver are integratedly controlled so that a voltage can be simultaneously written to an arbitrary pixel group of the display device.

  According to the present invention, it is possible to always compensate for the characteristic variation of the amorphous silicon TFT and the organic EL element, and both the measurement of the IV characteristic with high accuracy and the interpolation calculation of the coefficient of the pixel unit with high reliability can be achieved. In addition, there is an effect of reducing variation with time in luminance unevenness without impairing performance.

(A) is a drive circuit diagram of the organic EL active matrix concerning Embodiment 1 of the present invention, and (b) is a detailed circuit diagram of an output circuit of a gate driver. It is a figure which shows the operation | movement flow of the organic electroluminescent active matrix drive circuit which concerns on Embodiment 1 of this invention. It is a figure which shows the √IdV characteristic in each block. It is a figure which shows the relationship between a gradation voltage range and a gradation current. It is a figure which shows the timing of each process in the case of performing IV measurement process at the time of power activation. It is a figure which shows the timing of each process in the case of performing an IV measurement process in the display stop period provided for every display period. It is a figure which shows the timing of each process in the case of performing 1 block IV measurement process over the several period of the display stop period provided for every display period. It is an organic EL active matrix drive circuit diagram concerning Embodiment 2 of the present invention. It is a figure which shows the operation | movement flow of the organic electroluminescent active matrix drive circuit which concerns on Example 2 of this invention. (A)-(c) is the drive method of the organic EL active matrix which concerns on Embodiment 2 of this invention, Comprising: The inclination coefficient A and offset B between the center pixels of the block adjacent to the vertical and horizontal direction are interpolated It is a figure which shows a process. (A)-(b) is a figure which shows the division | segmentation method of the block in the drive method of the organic electroluminescent active matrix which concerns on Embodiment 3 of this invention. (A)-(c) is a figure which shows the linear type | formula of (square root) IdV corresponding to each block in the drive method of the organic electroluminescent active matrix which concerns on Embodiment 3 of this invention. (A)-(b) is a figure which shows the example of the weighting to each pixel in a block in the drive method of the organic EL active matrix which concerns on Embodiment 3 of this invention. It is a figure which shows the interpolation method of the area | region where the block overlapped in the drive method of the organic electroluminescent active matrix which concerns on Embodiment 3 of this invention. It is a figure which shows the block which does not overlap in the drive method of the organic electroluminescent active matrix which concerns on Embodiment 3 of this invention. It is a figure which shows the interpolation method in the block which does not overlap in the drive method of the organic EL active matrix which concerns on Embodiment 3 of this invention. It is a figure which shows another operation | movement flow of the drive circuit of the organic EL active matrix which concerns on Example 2, 3 of this invention. It is a figure which shows the equivalent circuit of 1 pixel in the conventional organic EL display panel of an active matrix system. It is a figure which shows the time-dependent change of the current-voltage characteristic of TFT.

  Hereinafter, embodiments of the present invention will be described in detail.

(Embodiment 1)
FIG. 1A shows an organic EL active matrix drive circuit diagram according to Embodiment 1 of the present invention. The source driver 17 includes an IV measuring circuit 22 including a DA conversion array 29, an ammeter 21, an AD converter 23, and a reference data source 24 for applying a gradation voltage to a pixel circuit in the matrix display panel 20 (display device). It comprises a data storage circuit 25, a correction calculator 26, an operation switching circuit 27 and SW28. In the matrix display panel 20, a plurality of pixel circuits 10 shown in FIG.

  FIG. 1B shows a detailed circuit diagram of the output circuit of the gate driver. The gate driver 18 that controls the row direction of the display panel includes an output circuit 41, an all-line selection circuit 42 that turns on all rows simultaneously, and a block selection circuit 43 that turns on a plurality of rows simultaneously. The output circuit 41 normally performs a logical OR operation on the output signal of the shift register 44 that is turned on in order for each row, all line selection signals that turn on all rows simultaneously, and block selection signals that turn on multiple rows simultaneously. And the same number of OR circuits 45.

  FIG. 2 shows an operation flow of the organic EL active matrix driving circuit according to the first embodiment. There are two processing systems here.

  One is a normal display process, which receives display data 30 from the outside, that is, a gradation signal, and converts the data value into a corresponding gradation voltage Vg by a DA converter 29 via a correction data storage circuit 25, and is converted into a matrix. This is a display processing system applied to the display panel 20.

  The other is an IV measurement processing system that measures the IV characteristics in which Vth and the voltage of the organic EL element are varied by the IV measurement circuit 22.

  First, an IV characteristic measurement processing system including S201 to S203 will be described.

  In one IV characteristic measurement, the matrix display panel 20 is divided into m × n blocks, and only one block is targeted. That is, only one target block is turned on, and all remaining blocks are turned off. In FIG. 1, one block at the upper left of the matrix display panel 20 is illustrated as a measurement target. Although it is desirable to increase the number of divisions as much as possible, an appropriate number is selected in consideration of measurement current accuracy and processing time.

  As shown in FIG. 3, the IV characteristic measurement in S201 is performed at least three points so that the √IdV characteristic can be approximated by a linear expression: √Id = AVg + Bi in one block. In this example, voltages Vg1i to Vg3i are given, three currents (Id1 to Id3) at that time are measured by the ammeter 21 and converted into digital values by the AD converter 23. Thereby, the basic IdV characteristic can be known.

As shown in FIG. 3, when the energization time becomes longer, An and Bn stored in the correction data storage circuit 25 are updated at this predetermined time interval.
However, since the expected currents cannot be obtained with the initial three voltages V1i to V3i over time, it is necessary to appropriately change to V1n to V3n. This is easy if the variation in IV characteristics is monitored. Further, the currents Id1 to Id3 shown in FIG. 3 do not need to have specific fixed current values, and can be any arbitrary current value that can approximate the target √IdV characteristic by a linear expression: √Id = AVg + Bi. That's fine.

  In S202, the IdV characteristic measured in S201 is converted to a √IdV characteristic, and a linear expression of the √IdV characteristic is obtained. In step S203, the coefficient An and the offset Bn of the linear expression are stored in the correction data storage circuit 25.

  The IV characteristic measurement process of S201 to S203 is performed for all blocks, and the process proceeds to a normal display processing system.

  As the energization time becomes longer, the linear expression changes from √Id (ti) = AiVg + Bi to √Id (tn) = AnVg + Bi. The coefficient An and the offset Bn in the linear expression thus updated are updated.

  In the display processing system, when the gradation signal Vgi is received in S204, the correction calculator 26 converts it into the corrected gradation signal Vgn using the equation (1) in S205.

Here, the coefficient of √IdV the Ai coefficients early √IdV, An is time, Bi is the threshold voltage Vthn of the initial threshold voltage Vthi, Bn is with time, have shifted be stored in the correction data storage circuit 25 It is a value.

  In step S206, the DA conversion array 29 converts the corrected gradation signal Vgn into a voltage Vgn.

  The IV characteristic measurement and the gradation signal Vg correction processing in S201 to S206 are performed in the same manner for all the blocks of the matrix display panel 20. The control to turn each block on and off is performed by supplying data to the DA converter 26 so that the current flows only to the block selected by the IV measurement circuit 22 using the reference data 24. The actual DA conversion array 26 has a number corresponding to the number of pixels.

  As a result, even if the threshold voltage Vth and the voltage of the organic EL element fluctuate as shown in FIG. 4, the gradation voltage range changes from ti to tn in accordance with the fluctuation, so that the luminance of the organic EL element is adjusted. The gradation current 0 to 100% does not vary. Accordingly, it is possible to eliminate fluctuations in luminance over time.

  Next, a temporal process for measuring the IV characteristic will be described. If it takes time to measure the IV characteristics, the original display function and performance are impaired, so it is necessary to select a time that does not hinder display. The timing for measuring the IV characteristics is determined by the operation switching circuit 27, and the SW 28 is controlled to enable the IV measuring circuit 22 side. Hereinafter, processing of the operation switching circuit 27 will be described.

  FIG. 5 is an example in which the IV characteristic of each block is measured in order, for example, for about 1 second, and the coefficient A and the offset B are obtained at once when the power is turned on. Although not shown, the IV characteristic measurement processing system can be implemented in the same manner before the power is turned off.

  The lower enlarged view of FIG. 5 is a more detailed timing diagram of IV measurement. Processing will be described in order.

  First, prior to IV measurement, the display screen is reset (black display). This reset is a process in which the output of the DA conversion array 29 is 0 V, all the outputs of the output circuit 41 of the gate driver 18 are turned on according to the instruction of the entire face selection circuit 42, and a voltage of 0 V is written to the pixel circuit.

  Next, in order to measure the IV characteristics at the three points, Vg1 to Vg3 are output in order from the position corresponding to each block as the measurement target of the DA conversion array 29. At that time, the gate driver 18 also partially turns on the output circuit 41 in response to an instruction from the block selection circuit 43 so that the voltages Vg1 to Vg3 can be written to the pixel circuit. Thereby, the current with respect to Vg1-Vg3 is measured with the ammeter 21.

  When the IV measurement of one block is completed, the process proceeds to the measurement of the next block, and the above IV characteristic measurement process is repeated until the last block (m, n).

  FIG. 6 shows an example in which the IV characteristic cannot be measured when the power is turned on and when the power is turned off. A display off period (V synchronization) is provided in one frame (screen), and the IV characteristic is obtained using this period. Perform the measurement process.

  The lower enlarged view of FIG. 6 is a more detailed timing diagram of IV measurement. As described above, after the display screen is reset prior to the IV characteristic measurement, Vg1 to Vg3 are sequentially output from the position corresponding to the block to be measured in the DA conversion array 29. At that time, the gate driver 18 also partially turns on the output circuit 41 in response to an instruction from the block selection circuit 43 so that the voltages Vg1 to Vg3 can be written to the pixel circuit. Thereby, the current with respect to Vg1-Vg3 is measured with the ammeter 21. This completes the measurement of IV characteristics for one block.

  Further, when the processing time in this off period is insufficient, there is also a method of measuring the three points of the IV characteristics separately for each point as shown in FIG. In this example, three IV characteristics are sequentially performed from the divided coordinates (1, 1) to the final coordinates (m, n).

  The lower enlarged view of FIG. 7 is a more detailed timing diagram of IV measurement. As described above, after the display screen is reset prior to the IV characteristic measurement, one of the three voltages Vg1 to Vg3 and one voltage Vgn corresponding to the block to be measured in the DA conversion array 29 Output from. At that time, the gate driver 18 also causes the output circuit 41 to be partially turned on in response to an instruction from the block selection circuit 43 so that the voltage Vgn can be written to the pixel circuit. Thereby, the current with respect to Vgn is measured by the ammeter 21. This completes the measurement of IV characteristics for one block.

  In this method, time is required until the IV characteristic measurement of the final (m, n) block is completed. However, since the voltage fluctuation of Vth and the organic EL element does not change greatly immediately, it is a time that does not hinder practical use.

  At this time, the measurement order is controlled by the IV measurement circuit 22 and the operation switching circuit 27 in conjunction with each other.

  As described above, in the first embodiment, it is possible to compensate for voltage fluctuations of Vth and the organic EL without affecting the display time.

(Embodiment 2)
In the first embodiment, an organic EL display panel is divided into a plurality of blocks, IV characteristics are measured for each of the divided blocks, a threshold voltage Vth and a slope coefficient A are obtained for each block, and the obtained threshold voltage Vth and the slope coefficient are obtained. A coefficient for each pixel is obtained by interpolating A.

  However, since the current flowing per pixel of the organic EL display panel is about several μA even at the highest luminance, the current cannot be accurately measured unless the area of one block is increased to some extent. However, increasing the area of one block reduces the number of divisions of the display screen, that is, leads to a decrease in the number of blocks for measuring IV characteristics. This means that the coefficient of the pixel unit is obtained from a small amount of information (number of blocks), and the reliability of the coefficient of the pixel unit obtained in the interpolation calculation is lowered.

  Therefore, in the second embodiment, by performing correction for interpolating the slope coefficient A and the offset B in the VI characteristics of each pixel between adjacent blocks, interpolation with higher accuracy than interpolation performed by each block alone becomes possible.

  FIG. 8 shows an organic EL active matrix drive circuit diagram according to Embodiment 2 of the present invention. The source driver 17 includes a DA conversion array 29, an ammeter 21, an AD converter 23, and a reference data source 24, which provide a gradation voltage to a pixel circuit in the matrix display panel 20 (display device). The correction data storage circuit 25 stores correction data in units, the correction data storage circuit 31 stores correction data in units of pixels, a correction calculator 26, an operation switching circuit 27, and a SW 28. In the matrix display panel 20, a plurality of pixel circuits 10 shown in FIG.

  On the other hand, in order to control the row direction of the matrix display panel 20, the gate driver 18 includes an output circuit 41, an all-line selection circuit 42 that turns on all rows simultaneously, and a block selection circuit 43 that turns on a plurality of rows simultaneously. Has been. As in the first embodiment, the output circuit 41 normally outputs an output signal of the shift register 44 that turns on only one row in order, an all-line selection signal that turns on all rows, and a block selection that turns on multiple rows simultaneously. It is composed of an OR circuit 45 that logically sums signals.

  As described above, the second embodiment differs from the first embodiment in the circuit configuration only in that the pixel correction data storage circuit 31 is provided between the correction data storage circuit 25 and the correction calculator 26 in the source driver 17. is there. The gate driver 18 has the same configuration as that of the first embodiment.

  FIG. 9 shows an operation flow of the organic EL active matrix driving circuit according to the second embodiment. Here, as in the first embodiment, there are two processing systems: a normal display processing system and an IV measurement processing system that measures IV characteristics. In the second embodiment, the display processing system is the same as that in the first embodiment, but the IV measurement processing system is different from the first embodiment.

Here, an IV measurement processing system composed of S 4 01 to S 4 06, which is different from the first embodiment, will be described.

  The IV characteristics are measured by dividing the matrix display panel 20 into m × n blocks and measuring the IV characteristics for only one block. That is, only one target block is turned on, and all remaining blocks are turned off. In FIG. 8, one block at the upper left of the matrix display panel 20 is illustrated as a measurement target. Although it is desirable to increase the number of divisions as much as possible, an appropriate number is selected in consideration of measurement current accuracy and processing time.

IV characteristic measurement of S 4 01 is a linear equation for √IdV properties in one block: performing minimum of three points to be approximated by √Id = AVg + Bi.

  As time passes, the expected current may not be obtained with these three voltages, so it is necessary to appropriately change to Vg1n to Vg3n. The currents Id1 to Id3 may be any three current points that can approximate the target √IdV characteristic to the linear expression: √Id = AVg + Bi.

When the measurement of the IV characteristic of one block is completed, at S 4 03, converted from IdV properties of the treated 1 to √IdV characteristics, determine the linear equation of its characteristics. In S 4 04, the coefficient An and the offset Bn of the linear expression are stored in the correction data storage circuit 25. As the energization time increases, the linear expression changes from √Id (ti) = AiVg + Bi to √Id (tn) = AnVg + Bi. An and Bn stored in the data storage circuit 25 are updated.

When the measurement of one block is completed, the measurement of IV characteristics is moved to the next block in order. If it is determined in S 4 05 that there is a block for which measurement has not been performed, the process proceeds to the next block to execute the processing from S 4 01.

When the IV characteristic measurement is completed for all the blocks and the update of the coefficient A and the offset B is completed, the coefficient An and the offset Bn are generated in S 4 06. Thereafter, they are stored in the correction data storage circuit 31.

  The coefficient and offset generation method for each pixel will be described with reference to FIGS. FIG. 10A illustrates a case where one block is 3 × 3 pixels.

First, the difference between the coefficient A and the offset B between adjacent blocks in the horizontal direction is proportionally distributed according to the position of the pixel, and only for the central pixel of the block based on equations (2) and (3) Interpolate.
A (m, n) + (A (m-1, n) -A (m, n)) * ΔL / Lx (2)
B (m, n) + (B (m−1, n) −B (m, n)) * ΔL / Lx (3)
Here, Lx is the distance between the centers of adjacent blocks in the horizontal direction, and ΔL is the position of the pixel to be interpolated. The center distance is expressed by the number of pixels.

  In FIG. 10B, the interpolated pixel is shown by horizontal hatching.

  Next, also in the vertical direction, all pixels are interpolated by a method in which the difference between the coefficient A and the offset B between adjacent blocks is proportionally distributed according to the position of the pixel. In FIG. 10C, pixels interpolated in the vertical direction are indicated by vertical hatching.

  Through the above processing, the coefficient A and the offset B interpolated for each pixel are stored in the correction data storage circuit 31.

  Thus, the IV characteristic measurement process is shifted to the normal display process at the end.

In S 4 08 of the display processing system, after receiving the gradation voltage signal Vgi in units of pixels, the correction calculator 26 uses the expression (1) to correct the gradation voltage signal Vgn corrected in units of pixels as in the first embodiment. Convert with.

Next, in S 4 09, the DA conversion array 29 converts the corrected gradation signal Vgn into the voltage Vgn.

  As a result, as in the first embodiment, even if Vth and the voltage of the organic EL element fluctuate as shown in FIG. 4, the gradation voltage range changes as ti to tn. The gradation current 0 to 100% to be adjusted does not vary. Accordingly, it is possible to eliminate fluctuations in luminance over time.

  The temporal processing of the IV characteristic measurement of the second embodiment can be performed in the same manner as in the first embodiment, and the processing of the operation switching circuit 27 in the second embodiment is performed in the same manner as in the first embodiment.

  However, as shown in FIG. 6, since the IV characteristic cannot be measured when the power is turned on and off, a display off period (V synchronization) is provided in one frame (screen), and this period is used for IV measurement. Measurement and correction data (coefficient A and offset B) of all blocks cannot be performed at once. Therefore, as shown in FIG. 17, the IV measurement processing flow is to process coefficient A and offset B while confirming the end of IV characteristic measurement in each block in S1702 and the end of correction data in all blocks in S1705, S1703, It is necessary to determine whether to execute S1704 and S1706.

  As a result, it is possible to compensate for Vth and organic EL voltage fluctuations without hindering the display time.

(Embodiment 3)
The third embodiment uses the same organic EL active matrix driving circuit as that of the second embodiment and has a VI measurement processing system different from that of the second embodiment.

  In the first and second embodiments, the organic EL display panel is divided into a plurality of blocks, the IV characteristics are measured for each of the divided blocks, the threshold voltage Vth and the slope coefficient A are obtained for each block, and the obtained threshold voltage Vth and A coefficient for each pixel is obtained by interpolating the slope coefficient A.

  However, since the current flowing per pixel of the organic EL display panel is about several μA even at the highest luminance, the current cannot be accurately measured unless the area of one block is increased to some extent. However, increasing the area of one block reduces the number of divisions of the display screen, that is, leads to a decrease in the number of blocks for measuring IV characteristics. This means that the coefficient of the pixel unit is obtained from a small amount of information (number of blocks), and the reliability of the coefficient of the pixel unit obtained in the interpolation calculation is lowered.

  Therefore, in the third embodiment, when measuring the IV characteristic, the measurement area of the divided block has an area overlapping with an adjacent block. As a result, the pixel unit coefficient can be obtained from information of a plurality of blocks including the corresponding pixel, and the pixel unit coefficient is obtained with higher accuracy from a larger amount of information than when the display screen is simply divided without overlapping. be able to.

A method of generating the slope coefficient A and the offset B in S 4 06 in units of pixels will be described with reference to FIGS.

FIG. 11A illustrates a case where one block is 4 × 4 pixels. Further, as shown in FIG. 11B, adjacent blocks have a region where two pixels overlap each other. FIG. 12A shows block I in the upper left of FIG. 11B, FIG. 12B shows block II adjacent to the right, which overlaps with block I, and FIG. 12C shows block II and two pixels. The overlapping block III on the right is shown. Further, the slope coefficient A and the offset B for each block obtained in S 4 03 and S 4 04 of the VI measurement processing system are as follows: the slope coefficient of block I is AI, the offset is BI, and the slope coefficient of block II is AII, The offset is BII, the slope coefficient of block III is AIII, and the offset is BIII.

  Next, weighting is performed on the slope coefficient A and offset B for each block. As shown in FIG. 13A, each block has 4 × 4 pixels. If so, it can have a maximum of 16 different weighting factors from a to p. Further, FIG. 13 (b) shows an example having a weighting factor proportional to the distance from the center of the block. Here, among 4 × 4 pixels, the weighting factor of the central four pixels is 2, and the weighting factor of the surrounding 12 pixels is shown. 1 is assumed. Interpolation is performed using the slope coefficient A and offset B for each block and the weight coefficient in the block, and the slope coefficient A and offset B are generated in pixel units.

  Next, the interpolation calculation will be described. In the example shown in FIG. 14, only the horizontal direction is described. However, the interpolation calculation similar to the horizontal direction is performed in the vertical direction to generate a tilt coefficient and an offset in units of pixels. I will do it.

In FIG. 14, if the pixel whose coefficient is to be calculated is (i), since the pixel of (i) is included in block I and block II, interpolation is performed using the slope coefficients AI and AII and offsets BI and BII. An operation is performed. At this time, using the weighting coefficient of FIG. 14B, it can be seen that the pixel of (i) is the position of the weighting coefficient 2 of block I and the position of the weighting coefficient 1 of block II. From these relationships, the inclination coefficient A (i) of the pixel of (i) can be obtained by the interpolation calculation formula of the following formula (4).
A (i) = (2 × AI + 1 × AII) / 3 Formula (4)
Similarly, the pixel offset B (i) of (i) can be obtained by the following equation (5).
B (i) = (2 × BI + 1 × BII) / 3 Formula (5)
The reason for dividing by 3 in the above equations (4) and (5) is to return the values of AI, AII, BI, and BII multiplied by the weighting factors of block I and block II to the original values. , The sum of the weighting coefficients (2 + 1 = 3) used in the equations (4) and (5).

Similarly, when the coefficient of the pixel of (ii) is obtained, it can be obtained by the following expressions (6) and (7).
A (ii) = (1 × AI + 2 × AII) / 3 Formula (6)
B (ii) = (1 × BI + 2 × BII) / 3 Formula (7)
Similarly, when obtaining the coefficient of the pixel of (iii), it can be obtained by the following equations (8) and (9).
A (iii) = (2 × AII + 1 × AIII) / 3 Formula (8)
B (iii) = (2 × BII + 1 × BIII) / 3 Formula (9)
Here, a weighting factor proportional to the distance from the center of the block in FIG. 13B is used, but the present invention is not limited to this, and the 16 weighting factors shown in FIG. It doesn't matter. Even in this case, the value to be divided is not changed by using the sum of the weighting coefficients that are multiplied in the interpolation equation.

  As shown in FIG. 15, the four corner areas of the matrix display panel 20 are areas where there are no overlapping blocks in adjacent blocks in both the horizontal and vertical directions. In the case of these regions, the above interpolation calculation is not performed, and the coefficient of the block including the pixel for which the coefficient is obtained is used as it is as the coefficient of the pixel unit.

In the example shown in FIG. 16, only the horizontal direction is described, but the same applies to the vertical direction. In FIG. 16, if the pixel whose coefficient is to be calculated is (i) ′, the block including the pixel of (i) ′ is the block I. Therefore, the slope coefficient AI and the offset BI are used as they are as a coefficient in units of pixels. It can obtain | require by following formula (10) and Formula (11).
A (i) ′ = AI (10)
B (i) ′ = BI (11)
Similarly, when the coefficient of the pixel of (ii) ′ is obtained, it can be obtained by the following equations (12) and (13).
A (ii) ′ = AI (12)
B (ii) ′ = BI Expression (13)
In FIG. 12A, one block on which IV measurement is performed is 4 × 4 pixels. However, the present invention is not limited to this. Similarly, in the area where adjacent blocks overlap in FIG. It is not limited to.

  Through the above processing, the slope coefficient A and the offset B interpolated for each pixel are stored in the correction data storage circuit 31.

  Up to this point, the IV characteristic measurement process is terminated, and the normal display process is started.

In S 4 08 of the display process, after receiving the gradation voltage signal Vgi in pixel units, the correction calculator 26 applies the pixel to the gradation voltage signal Vgn corrected using the expression (1) as in the first and second embodiments. Convert in units.

Next, in S 4 09, the DA conversion array 29 converts the corrected gradation signal Vgn into the voltage Vgn.

  As a result, as in the first and second embodiments, even when Vth and the voltage of the organic EL element fluctuate as shown in FIG. 4, the gradation voltage range changes as ti to tn. The gradation current for adjusting the brightness of 0% to 100% does not vary. Accordingly, it is possible to eliminate fluctuations in luminance over time.

  The temporal processing of the IV characteristic measurement of the third embodiment can be performed in the same manner as in the first and second embodiments, and the processing of the operation switching circuit 27 in the third embodiment is performed in the same manner as in the first and second embodiments. Is called.

  However, as shown in FIG. 6, since the IV characteristic cannot be measured when the power is turned on and off, a display off period (V synchronization) is provided in one frame (screen), and this period is used for IV measurement. Measurement and correction data (coefficient A and offset B) of all blocks cannot be performed at once. Therefore, as shown in FIG. 17, the IV measurement processing flow is to process coefficient A and offset B while confirming the end of IV characteristic measurement in each block in S1702 and the end of correction data in all blocks in S1705, S1703, It is necessary to determine whether to execute S1704 and S1706.

  As a result, it is possible to compensate for Vth and organic EL voltage fluctuations without hindering the display time.

10 pixel circuit 11 organic EL
12 TFT
13 TFT
DESCRIPTION OF SYMBOLS 14 Capacitor 15 Source signal line 16 Gate signal line 17 Source driver 18 Gate driver 19 Power supply 20 Matrix display panel 21 Ammeter 22 IV (current-voltage) measuring circuit 23 AD converter 24 Reference power supply 25 Correction data storage circuit 26 Correction calculator 27 Operation Switching Circuit 28 Switch 29 DA Conversion Array 30 Display Data 41 Output Circuit 42 All Line Selection Circuit 43 Block Selection Circuit 44 Shift Register 45 OR Circuit

Claims (11)

In a display device having an organic EL element and an amorphous Si-TFT and forming a matrix,
Dividing the screen of the display device into m × n (m, n: positive integer) in units of blocks each including a predetermined number of pixels;
A first measuring step of sequentially measuring a first current-voltage characteristic for each of the divided blocks;
A second measuring step of sequentially measuring a second current-voltage characteristic for each of the divided blocks at a predetermined time interval from the first measuring step;
A gradation voltage signal, which is display data that provides a predetermined gradation current signal based on the first current-voltage characteristic, is converted from the gradation voltage signal based on the second current-voltage characteristic. Correcting the grayscale voltage signal from the first and second current-voltage characteristics to provide a regulated current signal;
I have a,
The correcting step includes
First and second linear expressions representing the relationship between the square root of the current and the voltage are calculated from the first and second current-voltage characteristics, and the slope coefficient and offset of the first and second linear expressions are calculated. Correcting the gradation voltage signal using
A first difference between a slope coefficient and an offset between central pixels adjacent to one of the column direction and the row direction is proportionally distributed to the slope coefficient and offset of the pixels between the center pixels arranged in the one direction, and the vertical direction and The center pixel adjacent to the other in the horizontal direction and the second difference in the slope coefficient and the offset between the pixels to which the first difference is proportionally distributed are the center pixel and the first difference arranged in the other In proportion to the slope coefficient and offset of the pixel between the proportionally distributed pixels to correct the slope coefficient and offset of the first and second linear equations for each pixel;
Correcting the gradation voltage signal for each pixel using the corrected slope coefficients and offsets of the first and second linear equations;
A method for driving an organic EL active matrix comprising : In a display device having an organic EL element and an amorphous Si-TFT and forming a matrix,
Dividing the screen of the display device into m × n (m, n: positive integer) in units of blocks each including a predetermined number of pixels;
A first measuring step of sequentially measuring a first current-voltage characteristic for each of the divided blocks;
A second measuring step of sequentially measuring a second current-voltage characteristic for each of the divided blocks at a predetermined time interval from the first measuring step;
A gradation voltage signal, which is display data that provides a predetermined gradation current signal based on the first current-voltage characteristic, is converted from the gradation voltage signal based on the second current-voltage characteristic. Correcting the grayscale voltage signal from the first and second current-voltage characteristics to provide a regulated current signal;
Have
The correcting step includes
First and second linear expressions representing the relationship between the square root of the current and the voltage are calculated from the first and second current-voltage characteristics, and the slope coefficient and offset of the first and second linear expressions are calculated. and correcting the gradation voltage signal with,
The block has a region that overlaps with a block adjacent to one or both of the vertical and horizontal directions, and a predetermined weight coefficient proportional to the distance from the center is assigned to each pixel, and the block overlaps. The slope coefficients and offsets of the first and second linear expressions for each pixel in the region are determined, and the slope coefficients and offsets of the first and second linear expressions for each block are determined for each pixel of the block. A step of adding together the proportion of assigned weighting factors;
Correcting the grayscale voltage signal for each pixel using the interpolated slope coefficients and offsets of the first and second linear equations;
A method for driving an organic EL active matrix comprising : The measuring step includes the step of measuring the current-voltage characteristics of each block by simultaneously controlling the source driver and the gate driver to simultaneously write a voltage to an arbitrary pixel group of the display device. The driving method of the organic EL active matrix according to claim 1 or 2 . The step of measuring includes a step of measuring three or more current-voltage characteristics for each block after the display device is turned off (black display).
Step method of driving the organic EL active matrix according to any one of claims 1 to 3, characterized in that it comprises a step of storing in the storage device calculated by the tilt coefficient and offset of the linear equation for the correction . The driving method of the organic EL active matrix according to any one of claims 1 to 4 which comprises carrying out the step of the measuring when the display device power-on or cut-off is a period not performed ordinary display processing . The display stop period for each screen that is the display cycle of the display device is provided for one row or one horizontal time or more, and the current-voltage characteristics of one block are measured during the display stop period. Item 5. A method for driving an organic EL active matrix according to any one of Items 1 to 4 . Claim 1, characterized in that the display stop period over a plurality of cycles of measurement of the voltage characteristics - the display is provided a predetermined time period to stop the display cycle become one screen to display each of the device, the current of one block 5. The driving method of an organic EL active matrix according to any one of 1 to 4 . An organic EL active matrix driving circuit for driving a display device having an organic EL element and an amorphous Si-TFT and forming a matrix,
The screen of the display device is divided into m × n (m, n: positive integer) in units of a block made up of a predetermined number of pixels, and current-voltage characteristics for each of the divided blocks are measured in order. A voltage measurement circuit;
A correction data storage circuit for storing the measured current-voltage characteristics;
A grayscale voltage signal, which is display data for providing a predetermined grayscale current signal based on the first current-voltage characteristic stored in the correction data storage circuit, is determined from the first current-voltage characteristic at a predetermined time interval. The gradation voltage is determined from the first and second current-voltage characteristics so as to give the predetermined gradation current signal from the gradation voltage signal based on the second current-voltage characteristics measured at the same time. A correction arithmetic unit for correcting a signal, calculating first and second linear expressions representing a relationship between a square root of a current and a voltage from the first and second current-voltage characteristics; The gradation voltage signal is corrected using the slope coefficient and the offset of the second linear expression, and the first difference between the slope coefficient and the offset between the central pixels adjacent in one of the column direction and the row direction is the one Between the central pixels arranged in Proportionally distributed to the prime slope coefficient and offset, and the second difference between the slope coefficient and offset between the center pixel adjacent to the other of the other in the vertical direction and the horizontal direction and the first difference is proportionally distributed The central pixel arranged on the other side and the first difference are proportionally distributed to the inclination coefficient and offset of the pixels between the proportionally distributed pixels, and the inclination coefficients of the first and second linear expressions for each pixel And a correction calculator for correcting the offset ,
A source driver comprising: a DA converter array for controlling the column direction of the display device based on the corrected gradation voltage signal; and a gate driver comprising an output circuit for controlling the row direction of the display device, A drive circuit for an organic EL active matrix, wherein the source driver and the gate driver can be integratedly controlled so that a voltage can be simultaneously written to an arbitrary pixel group of the display device. An organic EL active matrix driving circuit for driving a display device having an organic EL element and an amorphous Si-TFT and forming a matrix,
  The screen of the display device is divided into m × n (m, n: positive integer) in units of a block made up of a predetermined number of pixels, and current-voltage characteristics for each of the divided blocks are measured in order. A voltage measurement circuit;
  A correction data storage circuit for storing the measured current-voltage characteristics;
  A grayscale voltage signal, which is display data for providing a predetermined grayscale current signal based on the first current-voltage characteristic stored in the correction data storage circuit, is determined from the first current-voltage characteristic at a predetermined time interval. The gradation voltage is determined from the first and second current-voltage characteristics so as to give the predetermined gradation current signal from the gradation voltage signal based on the second current-voltage characteristics measured at the same time. A correction arithmetic unit for correcting a signal, calculating first and second linear expressions representing a relationship between a square root of a current and a voltage from the first and second current-voltage characteristics; The gradation voltage signal is corrected using the slope coefficient and the offset of the second linear expression, and the block has a region that overlaps with a block adjacent to one or both of the vertical and horizontal directions, and the block includes Is from the center to each pixel A predetermined weight coefficient proportional to the separation is assigned, and the slope coefficient and offset of the first and second linear expressions for each pixel in the overlapping region of the block are set as the first and second slope coefficients and the second for each block. A correction calculator, which is obtained by adding the slope coefficient and the offset of the linear expression of each of them by the ratio of the weight coefficient assigned to each pixel of the block;
  A DA conversion array for controlling the column direction of the display device based on the corrected gradation voltage signal;
  A source driver with, and
  Gate driver having an output circuit for controlling the row direction of the display device
An organic EL active matrix drive circuit, wherein the source driver and the gate driver are integratedly controlled, and a voltage can be simultaneously written to an arbitrary pixel group of the display device. A display panel that has an organic EL element and an amorphous Si-TFT and forms a matrix,
The screen of the display device is divided into m × n (m, n: positive integer) in units of a block made up of a predetermined number of pixels, and current-voltage characteristics for each of the divided blocks are measured in order. A voltage measurement circuit;
A correction data storage circuit for storing the measured current-voltage characteristics;
A grayscale voltage signal, which is display data for providing a predetermined grayscale current signal based on the first current-voltage characteristic stored in the correction data storage circuit, is determined from the first current-voltage characteristic at a predetermined time interval. The gradation voltage is determined from the first and second current-voltage characteristics so as to give the predetermined gradation current signal from the gradation voltage signal based on the second current-voltage characteristics measured at the same time. A correction arithmetic unit for correcting a signal, calculating first and second linear expressions representing a relationship between a square root of a current and a voltage from the first and second current-voltage characteristics; The gradation voltage signal is corrected using the slope coefficient and the offset of the second linear expression, and the first difference between the slope coefficient and the offset between the central pixels adjacent in one of the column direction and the row direction is the one Between the central pixels arranged in Proportionally distributed to the prime slope coefficient and offset, and the second difference between the slope coefficient and offset between the center pixel adjacent to the other of the other in the vertical direction and the horizontal direction and the first difference is proportionally distributed The central pixel arranged on the other side and the first difference are proportionally distributed to the inclination coefficient and offset of the pixels between the proportionally distributed pixels, and the inclination coefficients of the first and second linear expressions for each pixel And a correction calculator for correcting the offset ,
A source driver comprising: a DA converter array for controlling the column direction of the display device based on the corrected gradation voltage signal; and a gate driver comprising an output circuit for controlling the row direction of the display device, An organic EL active matrix display device, wherein the source driver and the gate driver are integrated and controlled to simultaneously write a voltage to an arbitrary pixel group of the display device. A display panel that has an organic EL element and an amorphous Si-TFT and forms a matrix,
  The screen of the display device is divided into m × n (m, n: positive integer) in units of a block made up of a predetermined number of pixels, and current-voltage characteristics for each of the divided blocks are measured in order. A voltage measurement circuit;
  A correction data storage circuit for storing the measured current-voltage characteristics;
  A grayscale voltage signal, which is display data for providing a predetermined grayscale current signal based on the first current-voltage characteristic stored in the correction data storage circuit, is determined from the first current-voltage characteristic at a predetermined time interval. The gradation voltage is determined from the first and second current-voltage characteristics so as to give the predetermined gradation current signal from the gradation voltage signal based on the second current-voltage characteristics measured at the same time. A correction arithmetic unit for correcting a signal, calculating first and second linear expressions representing a relationship between a square root of a current and a voltage from the first and second current-voltage characteristics; The gradation voltage signal is corrected using the slope coefficient and the offset of the second linear expression, and the block has a region that overlaps with a block adjacent to one or both of the vertical and horizontal directions, and the block includes Is from the center to each pixel A predetermined weight coefficient proportional to the separation is assigned, and the slope coefficient and offset of the first and second linear expressions for each pixel in the overlapping region of the block are set as the first and second slope coefficients and the second for each block. A correction calculator, which is obtained by adding the slope coefficient and the offset of the linear expression of each of them by the ratio of the weight coefficient assigned to each pixel of the block;
  A DA conversion array for controlling the column direction of the display device based on the corrected gradation voltage signal;
  A source driver with, and
  Gate driver having an output circuit for controlling the row direction of the display device
An organic EL active matrix display device, wherein the source driver and the gate driver are integratedly controlled and a voltage can be simultaneously written to an arbitrary pixel group of the display device.

Images