JP4753351B2 - Driving device for light emitting display panel and driving method thereof - Google Patents

Description

  The present invention relates to a driving device and a driving method for a light emitting display panel in which a self light emitting element that is driven at a constant voltage is formed at each intersection of a plurality of scanning selection lines and a plurality of data lines.

  Development of a display using a display panel in which self-light emitting elements are arranged in a matrix has been widely promoted. As a self-luminous element used in such a display panel, an organic EL (electroluminescence) element using an organic material for a light-emitting layer has attracted attention. This is also due to the fact that the use of an organic compound that can be expected to have good light-emitting characteristics for the light-emitting layer of the EL element has led to an increase in efficiency and longevity that can withstand practical use.

As a display panel using such organic EL elements, a passive matrix display panel in which EL elements are simply arranged in a matrix (see, for example, Patent Document 1) and an EL element arranged in a matrix are each provided with active TFTs. An active matrix display panel to which elements are added (for example, see Patent Document 2) has been proposed. The latter active matrix type display panel can achieve lower power consumption and less cross-talk between pixels compared to the former passive matrix type display panel. Suitable for high definition display.
JP 2003-288053 A JP 2003-316315 A

  FIG. 1 shows the most basic circuit configuration corresponding to one pixel 11 in a conventional active matrix display device. In FIG. 1, the gate of the control TFT (Tr 1) composed of N channels is connected to the scan line from the scan driver 12, and its source is connected to the data line from the data driver 13. Further, the drain of the control TFT (Tr1) is connected to the gate of the drive TFT (Tr2) constituted by the P channel and to one terminal of the charge holding capacitor C1.

  On the other hand, the source of the driving TFT (Tr2) is connected to the other terminal of the capacitor C1, and is also connected to a power source (VDD) that supplies a driving current to a self-luminous element (for example, EL element) E1. The drain of the driving TFT (Tr2) is connected to the anode of the self-light-emitting element E1, and the cathode of the self-light-emitting element is connected to a reference potential point (earth), for example. A large number of pixels 11 having this configuration are arranged in a matrix, thereby forming a light emitting display panel.

  When the ON control voltage (Select) is supplied to the gate of the control TFT (Tr1) in FIG. 1 via the scanning line, the control TFT (Tr1) is supplied with the data voltage (Vdata) from the data line supplied to the source. A current corresponding to is supplied from the source to the drain. Therefore, the capacitor C1 is charged while the gate of the control TFT (Tr1) is on-voltage, and the voltage is supplied to the gate of the drive TFT (Tr2). Therefore, the light emitting element E1 is driven to emit light by the drain current of the driving TFT (Tr2) based on this.

  When the gate of the control TFT (Tr1) is turned off, the control TFT (Tr1) becomes a so-called cut-off, and the drain of the control TFT (Tr1) is opened, but the drive TFT (Tr2) is a capacitor. The gate voltage is held by the charge accumulated in C1, the driving current is maintained until the next scanning, and the light emission of the self-light emitting element E1 is also maintained.

  As the driving means of the pixel 11 having the configuration shown in FIG. 1, constant current driving or constant voltage driving can be employed. In the case where the former constant current driving is adopted as the driving means of the pixel 11, the Vdata supplied from the data driver 13 is written in the capacitor C1, and the driving is performed based on the value of Vdata written in the capacitor C1. The drain current ID of the TFT for use (Tr2) is controlled.

  On the other hand, when the latter constant voltage driving is employed, Vdata generated from the data driver 13 is written to the capacitor C1 via the control TFT (Tr1), and the Vdata written to the capacitor C1 is driven. Applied to the gate of the TFT (Tr2). At this time, the driving TFT (Tr2) functions as a switch according to Vdata written in the capacitor C1, and the driving current (drain current) ID supplied to the self-light emitting element E1 is supplied from the power supply (VDD). It is controlled by the voltage value.

  By the way, as shown in the graph of FIG. 2, the self-light-emitting element E1 has a change characteristic in which the forward voltage (VF) temporarily decreases significantly in the initial lighting stage (approximately 10 hours in cumulative light emission time). It is known. That is, since the light-emitting element to be turned on differs depending on the light-emitting display pattern, the self-light-emitting element having different forward voltage (VF) in the plane of the light-emitting display panel in the initial stage depending on the cumulative light emission time for each light-emitting element. Elements will be mixed.

  The self-light emitting element has a diode component and a parasitic capacitance in parallel with the diode component, and exhibits a light emission intensity substantially proportional to the forward current of the self-light emitting element in a state equal to or higher than the light emission threshold voltage. In the constant current driving described above, the potential applied to the self-light-emitting element decreases following the primary decrease in the forward voltage (VF), so that the self-light-emitting element has a reduced forward voltage (VF). However, an excessive increase in current does not occur. For this reason, substantially appropriate light emission luminance can be obtained for all the self-light-emitting elements.

  On the other hand, in the constant voltage driving described above, since a constant potential is always applied to all the self-luminous elements even when the forward voltage (VF) is reduced in the initial stage of use, the forward voltage ( In a self-luminous element having a reduced VF), the current increases excessively and the luminance increases as shown in the graph of FIG. 2 (the luminance efficiency with respect to such forward voltage is referred to as VL efficiency). For this reason, in the initial stage until the accumulated light emission time of each self-light-emitting element reaches approximately 10 hours, the display portion by the self-light-emitting element having a long accumulated light-emission time is displayed even if the same luminance data is displayed. Phenomenon that the luminance becomes higher than the display portion by the self-light emitting element having a short accumulated light emission time (in the present invention, this phenomenon is referred to as “reverse image sticking in the initial stage of light emission”. Was called).

  As a specific example, an end user first uses an electronic device equipped with a self-luminous display panel, and among the self-luminous elements forming the display panel, a static pattern in which only some of the self-luminous elements emit light is accumulated. Display for 8 hours. In that case, a self-light-emitting element having an accumulated light emission time of 8 hours and a self-light-emitting element having a time of 0 hours are mixed in the display panel.

  Subsequently, for example, when an intermediate gray solid screen is displayed on the entire screen, as shown by the VF curve in FIG. The forward voltage (VF) applied to the self-luminous element having a cumulative light emission time of 8 hours with respect to the directional voltage (VF) is a remarkably low value. Therefore, in the self-light-emitting element having a cumulative light emission time of 8 hours, the current increases excessively compared to the self-light-emitting element having a cumulative light emission time of 0 hour. As a result, as schematically shown in FIG. 3B, the phenomenon of “reverse burn-in” in which the self-light-emitting element having an accumulated light emission time of 8 hours is displayed brighter than the self-light-emitting element of 0 hour. It has occurred.

  In order to solve the problem of “reverse burn-in”, the forward voltage (VF), which decreases in the initial lighting stage, rises again, and no excessive current flows in the self-luminous element. It is conceivable to perform aging while continuing to drive the display device. However, when aging driving is performed on all products in a factory before shipment, there is a problem that the production efficiency is lowered and the production cost is increased.

  The present invention has been made paying attention to the above-mentioned technical problems, and in a self-luminous element that is driven at a constant voltage, the luminance of the light emission caused by a decrease in the forward voltage (VF) at the initial lighting stage. It is an object of the present invention to provide a driving device and a driving method for a light emitting display panel that can reduce the occurrence of defects.

The light emitting display panel driving apparatus according to the present invention, which has been made to solve the above-described problems, is a self-driving device that is driven at a constant voltage at each intersection of a plurality of scanning selection lines and a plurality of data lines. A light-emitting display panel driving apparatus in which a light-emitting element is formed, comprising: voltage applying means for applying a driving voltage to the self-light-emitting element; and control means for controlling a value of a voltage applied by the voltage applying means. The control means is a period until the cumulative lighting time of the self-light-emitting element reaches a predetermined time, and the lighting until the forward voltage of the self-light-emitting element starts to decrease and rises as the cumulative lighting time elapses. In the initial period, the voltage value applied by the voltage applying unit is variably controlled so as to decrease following the decrease of the forward voltage .

A driving method according to the present invention for solving the above-described problem is that, as described in claim 7, a self-luminous element in which constant voltage driving is performed at each intersection of a plurality of scanning selection lines and a plurality of data lines. A method of driving a light emitting display panel in which a cumulative lighting time of the self light emitting element reaches a predetermined time, and a forward voltage of the self light emitting element is measured as the cumulative lighting time elapses. Accordingly, in the initial period of lighting from the decrease to the increase, the step of variably controlling the voltage value for driving the self-light emitting element to decrease following the decrease in the forward voltage is performed. Have.

  A light emitting display panel driving device and a driving method thereof according to the present invention will be described below based on the embodiments shown in the drawings. In the following description, portions corresponding to the respective portions shown in FIG. 1 already described are denoted by the same reference numerals, and therefore descriptions of individual functions and operations are appropriately omitted.

  FIG. 4 is a block diagram showing a first embodiment of a light emitting display panel driving apparatus according to the present invention. FIG. 5 is a diagram showing a circuit configuration example of one pixel among the pixels 10 arranged in a matrix on the light emitting display panel 40 of FIG. Note that the light-emitting elements of the light emitting display panel driving apparatus according to the present invention are controlled to emit light by constant voltage driving. Therefore, the organic EL element (E1) shown in FIG. 5 emits light when driven at a constant voltage.

  In the driving apparatus 100 shown in FIG. 4, the control circuit 21 (control means) controls the operation of the light emitting display panel 40 including the data driver 24, the scanning driver 25, and the pixels 10 arranged in a matrix. It is made like that. First, the input analog video signal is supplied to the control circuit 21 and the analog / digital (A / D) converter 22. The control circuit 21 generates a clock signal CK for the A / D converter 22, a write signal W for the frame memory 23, and a read signal R based on a horizontal synchronization signal and a vertical synchronization signal in the analog video signal.

  The A / D converter 22 samples the input analog video signal based on the clock signal CK supplied from the control circuit 21, converts it into pixel data corresponding to each pixel, and generates a frame memory. It acts to supply to 23. The frame memory 23 operates to sequentially write each pixel data supplied from the A / D converter 22 to the frame memory 23 in accordance with a write signal W from the control circuit 21.

  When the writing of data for one screen (n rows, m columns) in the self-luminous display panel 40 is completed by such a writing operation, the frame memory 23 uses, for example, 6 pixels per pixel by the read signal R supplied from the control circuit 21. The data is sequentially supplied to the data driver 24 as bit pixel data. The data driver 24 sends a data voltage (Vdata) to each data line (data line) B1 to Bm.

  On the other hand, a timing signal is sent from the control circuit 21 to the scanning driver 25, and based on this, the scanning driver 25 sequentially sends gate-on voltages to the scanning lines (scanning selection lines) A1 to An. Accordingly, the drive pixel data for each row read from the frame memory 23 as described above is addressed for each row by the scan of the scan driver 25, and one screen is displayed.

  Further, as shown in FIG. 4, the driving device 100 includes voltage applying means 27 that applies a voltage to the anode 31, and the operation of the voltage applying means 27 is controlled by the control circuit 21. The voltage applying unit 27 applies a predetermined constant voltage to the anode 31 after a predetermined cumulative drive time (cumulative lighting time of the organic EL element) in the driving device 100, but during the predetermined cumulative drive time. The voltage applied to the anode 31 operates so as to selectively change following the change in the forward voltage. This variable voltage control is performed by the control circuit 21 and its purpose is to reduce malfunctions such as reverse image sticking.

  Note that the predetermined cumulative drive time is the time until the change in the forward voltage (VF) in the EL element E1 starts to increase from the decrease by accumulating the light emission times of the EL elements E1 arranged in the display panel 40. (For example, 10 hours). That is, as shown in the graph of FIG. 2, the variable voltage control is performed in a period until the characteristic tendency in which the current (brightness) increases as the lighting time is accumulated changes to a decreasing tendency.

  Next, a specific voltage variable control method will be described. As shown in FIG. 4, the driving apparatus 100 is provided with a non-volatile memory 33 as a first storage means, and the non-volatile memory 33 includes a first look-up table 33a as shown in FIG. Has been built. The information described in the look-up table 33a is data obtained in advance in consideration of the above-described VL efficiency, and an appropriate drive voltage value for always lighting the EL element with a predetermined luminance is the EL element. It is described corresponding to the cumulative lighting time.

  That is, each drive voltage value described in advance in the lookup table 33a is a value that follows a change in the forward voltage. Therefore, by applying the drive voltage corresponding to each cumulative lighting time described in the lookup table 33a at the corresponding cumulative lighting time, a substantially constant current always flows through the organic EL element E1. Yes. The control circuit 21 can read the drive voltage value with respect to the cumulative lighting time of the EL element from the lookup table 33a.

  The control circuit 21 is connected to an integration timer 34 that integrates the accumulated drive time. Thus, the control circuit 21 grasps the cumulative drive time of the drive device 100, that is, the cumulative lighting time of the EL element. Therefore, the control circuit 21 reads the optimum drive voltage value corresponding to the cumulative lighting time of the EL elements supplied from the integration timer 34 from the lookup table 33a constructed in the nonvolatile memory 33, and the voltage value is voltage application means. 27 is controlled to be applied.

  In the drive device 100 of the light emitting display panel configured as described above, after the electronic device equipped with this device has passed to the end user, the integration timer 34 is activated with the start of use, and during a predetermined cumulative drive time. For example (for 10 hours), the drive voltage is variably controlled in order to maintain a predetermined light emission luminance. When performing variable control of the drive voltage, the value of the voltage applied from the voltage application means 27 to the anode 31 is determined with reference to an appropriate drive voltage value described in the lookup table 33a.

  As described above, according to the first embodiment of the present invention, in the driving device 100 of the light emitting display panel, the predetermined light emission luminance is obtained by referring to the look-up table 33a during the predetermined cumulative driving time. In order to maintain it, the drive voltage is variably controlled. As a result, even when the forward voltage in some organic EL elements decreases in the initial lighting stage of the organic EL element, the drive voltage can be decreased (changed) following the forward voltage, Generation of excessive current in the EL element can be suppressed. That is, by suppressing the generation of an excessive current, there is no EL element in which the luminance is excessively increased in the initial stage of use of the electronic device, so that it is possible to reduce the occurrence of a malfunction such as reverse image sticking.

  Next, a second embodiment of the driving device and driving method of the light emitting display panel according to the present invention will be described. FIG. 7 is a block diagram showing the configuration of the light emitting display panel driving apparatus according to the second embodiment. Note that, since the configuration is partially different from the first embodiment described above, components having the same configuration and function are denoted by the same reference numerals, and detailed description thereof is omitted. In the driving device 100 shown in FIG. 7, as in the first embodiment, the voltage applied from the voltage applying means 27 to the anode 31 is variably controlled until the predetermined cumulative driving time. Is made. However, since the voltage variable control is partially different from the first embodiment, the configuration and method will be described.

  As shown in FIG. 7, the driving apparatus 100 includes a monitor element unit 35, a VF detection unit (forward voltage detection unit) 36 that detects a forward voltage of a monitor element (measurement element) included in the monitor element unit 35, and Is provided. As shown in the configuration of the monitor element unit 35 in FIG. 8, the monitor element unit 35 includes a constant current source 37 and a monitor element (measurement element) E2 made of an organic EL element. In the monitor element unit 35, an operation command is issued from the control circuit 21 as the drive device 100 is driven, and the constant current source 37 supplies a constant current to the monitor element E2, thereby driving the monitor element E2 to light.

  Further, the VF detection means 36 is configured to detect the forward voltage in the monitor element E2 as described above, and is configured to supply information of the detected voltage value to the control circuit 21. The control circuit 21 determines a drive voltage value that follows the forward voltage of the monitor element E2 during the above-described predetermined cumulative drive time, that is, a predetermined cumulative lighting time of the EL element (for example, 10 hours). The drive voltage is controlled to be applied from the voltage application means 27 to the anode 31.

  In the drive device 100 of the light emitting display panel configured as described above, after the electronic device equipped with this device has passed to the end user, the integration timer 34 is activated with the start of use, and during a predetermined cumulative drive time. For example (for 10 hours), the drive voltage is variably controlled in order to maintain a predetermined light emission luminance. When performing variable control of the drive voltage, the value of the voltage applied from the voltage application unit 27 to the anode 31 is determined based on the information on the forward voltage value supplied from the VF detection unit 36. .

  As described above, according to the second embodiment of the present invention, in the drive device 100 for the light emitting display panel, the order in the monitor element E2 supplied from the VF detection means 36 is maintained for a predetermined cumulative drive time. With reference to the information on the direction voltage value, the drive voltage is variably controlled in order to maintain a predetermined light emission luminance. As a result, even when the forward voltage in some organic EL elements decreases in the initial lighting stage of the organic EL element, the drive voltage can be decreased (changed) following the forward voltage, Generation of excessive current in the EL element can be suppressed. In other words, by suppressing the generation of excessive current, there is no EL element whose luminance increases excessively in the initial stage of use of the electronic device, so that occurrence of phenomena such as reverse image sticking can be reduced.

  In the first and second embodiments described above, the display panel 40 has organic EL elements E1 of a single color or two or more colors (R, G, B, etc.) arranged in two colors. When the above elements are arranged, the light emission luminance characteristics differ depending on the light emission color. Therefore, at the initial stage of lighting of the organic EL element, it is desirable to perform variable control of the driving voltage for each color of the organic EL element E1.

  Subsequently, a third embodiment according to the present invention will be described in the case where variable control of the drive voltage in each of the organic EL elements of each color is performed. FIG. 9 is a block diagram showing the configuration of the light emitting display panel driving apparatus according to the third embodiment. In addition, since the configuration is partially different from the first and second embodiments described above, components having the same configuration and function are denoted by the same reference numerals, and detailed description thereof is omitted. In the drive device 100 shown in FIG. 9, as in the first and second embodiments described above, the voltage applied from the voltage application means to the anode line is variably controlled until the predetermined cumulative drive time. Is made. However, since the voltage variable control is partially different from the first and second embodiments, the configuration and method will be described.

  In the third embodiment, for example, the organic EL element E1 uses three colors R, G, and B, and anode lines are provided separately for each color as shown in FIG. That is, voltage application means 27a, 27b, and 27c are provided for the anode lines 31a, 31b, and 31c corresponding to the respective colors, and each is configured to independently apply a voltage. The monitor element unit 35 is provided with a monitor element E2 of an EL element of one color (for example, R), and the VF detection means 36 detects the forward voltage of the R monitor element E2. Yes.

  Further, the driving device 100 includes a nonvolatile memory 38 as a second storage unit, and the nonvolatile memory 38 is a second memory in which the correspondence relationship between the light emission characteristics of R and other colors (G, B) is described. This lookup table 38a is constructed. The control circuit 21 can read the information in the lookup table 38a.

  In the drive device 100 of the light emitting display panel configured as described above, after the electronic device equipped with this device has passed to the end user, the integration timer 34 is activated with the start of use, and during a predetermined cumulative drive time. For example (for 10 hours), the drive voltage is variably controlled in order to maintain a predetermined light emission luminance. When performing variable control of the drive voltage, first, referring to the information of the forward voltage value of the R monitor element E2 supplied from the VF detection means 36, the voltage application means 27a for R uses the anode 31a. The value of the voltage applied to is determined.

  On the other hand, for EL elements of other colors (G, B) other than R, the control circuit 21 refers to the look-up table 38a and determines each drive voltage value. That is, with reference to the drive voltage value applied to the R EL element, the correspondence between the emission characteristics of the R element and the other color (G, B) elements is taken into consideration, and the voltage application means 27b to the anode 31b ( The value of the driving voltage applied to the G EL element) and the value of the driving voltage applied to the anode 31c (B EL element) from the voltage applying means 27c are determined.

  As described above, according to the third embodiment of the present invention, in the driving device 100 of the light emitting display panel, one color (R) supplied from the VF detecting means 36 is supplied for a predetermined cumulative driving time. With reference to the forward voltage value in the monitor element E2, the drive voltage is variably controlled in order to maintain a predetermined light emission luminance. On the other hand, for the other colors (G, B), the respective drive voltages are controlled based on the drive voltage values applied to the look-up table 38a and R elements.

  As a result, even when the forward voltage of some organic EL elements decreases in the initial lighting stage of each color organic EL element, the drive voltage can be decreased (changed) following the forward voltage. The generation of excessive current in the organic EL elements of the respective colors can be suppressed. In other words, by suppressing the generation of excessive current, there is no EL element whose luminance increases excessively in the initial stage of use of the electronic device, so that occurrence of phenomena such as reverse image sticking can be reduced.

It is a figure which shows the most basic circuit structure corresponding to one pixel in the conventional active matrix type display apparatus. It is a graph which shows the change of the brightness | luminance and forward voltage with respect to the accumulation light emission time of an organic EL element. It is the example for demonstrating the phenomenon of reverse image sticking, Comprising: The graph which shows the change of the forward voltage with respect to accumulation light emission time, and the figure which showed the display screen typically. It is the block diagram which showed 1st embodiment of the drive device of the light emission display panel concerning this invention. 5 is a diagram illustrating a circuit configuration example of one pixel among pixels arranged in a matrix on the light emitting display panel of FIG. 4. FIG. FIG. 5 is a diagram schematically illustrating a lookup table constructed in the nonvolatile memory of FIG. 4. It is the block diagram which showed 2nd embodiment of the drive device of the light emission display panel concerning this invention. It is a figure which shows typically the structure of the monitor element part of FIG. It is the block diagram which showed 3rd embodiment of the drive device of the light emission display panel concerning this invention.

Explanation of symbols

10 pixels 21 control circuit (control means)
24 Data Driver 25 Scan Driver 27 Voltage Application Unit 31 Anode 32 Cathode 33 Nonvolatile Memory (First Storage Unit)
33a Lookup table (first lookup table)
34 Integration timer 35 Monitor element part 36 VF detection means (forward voltage detection means)
37 Constant current source 38 Non-volatile memory (second storage means)
38a Look-up table (second look-up table)
40 Light-Emitting Display Panel 100 Drive Device A Scanning Line B Data Line C1 Capacitor E1 Organic EL Element (Self-Lighting Element)
E2 Monitor element (measurement element)
Tr1 control TFT
Tr2 driving TFT

Claims (11)

A light emitting display panel driving device in which a self-light emitting element that is driven at a constant voltage is formed at each intersection of a plurality of scanning selection lines and a plurality of data lines,
Voltage application means for applying a driving voltage to the self-luminous element, and control means for controlling the value of the voltage applied by the voltage application means,
The control means includes
In the period until the cumulative lighting time of the self-light-emitting element reaches a predetermined time, and in the initial lighting period until the forward voltage of the self-light-emitting element starts to decrease and rises as the cumulative lighting time elapses, A drive device for a light-emitting display panel, wherein the voltage value applied by the voltage applying means is variably controlled so as to decrease following the decrease in the forward voltage . Correspondence relationship between a first storage unit that is read-out controlled by the control unit and a driving voltage value that is built in the first storage unit and the self-light-emitting element is lit with a predetermined luminance and a cumulative lighting time With a first lookup table describing
The control means refers to the first look-up table in the predetermined cumulative lighting period, and determines a voltage value applied by the voltage application means corresponding to the cumulative lighting time of the self-luminous element. The drive device of the light emitting display panel according to claim 1. A measuring element, a constant current source for supplying a constant current to the measuring element, and a forward voltage detecting means for detecting a value of a forward voltage in the measuring element,
The said control means determines the voltage value which the said voltage application means applies based on the value of the forward voltage which the said forward voltage detection means detected in the said predetermined | prescribed cumulative lighting period. 1. A drive device for a light-emitting display panel according to 1. The light-emitting display panel is formed by arranging at least two colors of self-luminous elements.
The said control means controls the voltage value which the said voltage application means applies about the self-light-emitting element of each color in the said predetermined | prescribed cumulative lighting period, It is described in any one of Claim 1 thru | or 3 characterized by the above-mentioned. Drive device for light emitting display panel. A single color measuring element provided separately from the light emitting display panel formed by arranging the light emitting elements of at least two colors or more, a constant current source for supplying a driving current to the measuring element, and the measurement A forward voltage detecting means for detecting a value of a forward voltage in the element for use, a second storage means that is controlled to be read out by the control means, and the second storage means. A second look-up table describing the correspondence of the emission characteristics,
The control means includes the voltage applying means for the self-light emitting element of the same color as the measuring element based on the forward voltage value of the measuring element detected by the forward voltage detecting means during the predetermined cumulative lighting period. Determine the voltage value to be applied, and for the other color self-luminous elements, refer to the voltage value applied to the self-luminous element of the same color as the measurement element and the second lookup table, and apply the voltage 2. The driving device for a light emitting display panel according to claim 1, wherein a voltage value applied by the means is determined.   6. The drive device for a light emitting display panel according to claim 1, wherein the self light emitting element is an organic EL element. A driving method of a light emitting display panel in which a self-light emitting element that is driven at a constant voltage at each intersection of a plurality of scanning selection lines and a plurality of data lines is formed
In the period until the cumulative lighting time of the self-light-emitting element reaches a predetermined time, and in the initial lighting period until the forward voltage of the self-light-emitting element starts to decrease and rises as the cumulative lighting time elapses,
A method for driving a light-emitting display panel , comprising: variably controlling a voltage value for driving the self-light-emitting element to decrease following the decrease in the forward voltage . In the step of variably controlling the voltage value for driving the self-light-emitting element during the predetermined cumulative lighting period,
Reading out a first look-up table constructed in a first storage means and describing a correspondence relationship between a driving voltage value and a cumulative lighting time for the self-light-emitting element to light at a predetermined brightness;
8. The method of driving a light emitting display panel according to claim 7, wherein the step of determining a drive voltage value to be applied to the self light emitting element is performed with reference to the first look-up table. In the step of variably controlling the voltage value for driving the self-light-emitting element during the predetermined cumulative lighting period,
A step of detecting a forward voltage value of a measuring element that is provided separately from the self-luminous elements arranged in the light-emitting display panel and is supplied with a constant current from a constant current source;
The method for driving a light-emitting display panel according to claim 7, further comprising: determining a drive voltage value to be applied to the self-light-emitting element based on the detected forward voltage value. The light-emitting display panel is formed by arranging at least two colors of self-luminous elements.
10. The method according to claim 7, wherein a step of variably controlling a voltage value for driving and driving the self-light-emitting element is performed for each color self-light-emitting element during the predetermined cumulative lighting period. Driving method of the light emitting display panel. A single-color measuring element that is provided separately from the light-emitting display panel formed by arranging at least two colors of self-luminous elements in the predetermined cumulative lighting period and is supplied with a constant current from a constant current source Detecting the value of the forward voltage at
Determining a voltage value to be applied to a self-luminous element of the same color as the measuring element based on the detected forward voltage value of the measuring element;
For the self-light emitting elements of other colors, the voltage value applied to the self-light emitting element of the same color as the measuring element and the second storage means are constructed, and the correspondence relationship of the light emission characteristics between the respective color self-light emitting elements is described. The method for driving the light emitting display panel according to claim 7, wherein the step of determining a voltage value to be applied to the self light emitting element is performed with reference to the second lookup table.

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