JP2006243304A - Driving device and driving method for luminescent display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving device and a driving method for a luminescent display panel which can reduce shadowing caused by a lighting rate of a light emitting element and a condition of dimmer setting, to such a level that there is no problem on practical use. <P>SOLUTION: An analog video signal is supplied to a driving control circuit 11 and an A/D conversion circuit 12 and is converted to image data corresponding to individual pixels by the A/D conversion circuit 12 and is written in an image memory 13. A lighting rate of the light emitting element is obtained on the basis of the image data written in the image memory 13, and period control data for controlling a period t1 of each scan line is read out from a lookup table 14 on the basis of the lighting rate and dimmer setting data. The period t1 from a timing of application of a reverse bias voltage to a non-scan line to a timing of supply of a constant current as a light emission driving current to a lighting line is controlled by the period control data, and as a result, the occurrence of shadowing is suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a driving apparatus and a driving method that can be suitably employed for a passive matrix light emitting display panel using a capacitive light emitting element, and more particularly to a shadow generated due to a change in the lighting rate of the light emitting element. The present invention relates to a driving device and a driving method for a light-emitting display panel that can reduce the degree of occurrence of inging (lateral crosstalk) to a level that causes no problem in practice.

  With the widespread use of mobile phones and portable information terminals (PDAs), there is an increasing demand for display panels that have a high-definition image display function and that can be thin and achieve low power consumption. Liquid crystal display panels have been adopted in many products as display panels that satisfy these requirements. On the other hand, in recent years, organic EL (electroluminescence) elements that take advantage of the characteristic of being self-luminous elements have been put into practical use, and this is drawing attention as a next-generation display panel that replaces a conventional liquid crystal display panel. 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 device has led to higher efficiency and longer life that can withstand practical use.

  The above-mentioned organic EL element is basically formed by sequentially laminating a transparent electrode (anode) made of, for example, ITO, a light emitting functional layer, and a metal electrode (cathode) made of an aluminum alloy on a transparent substrate such as glass. It is configured. The light-emitting functional layer is a single light-emitting layer made of an organic compound, or a two-layer structure composed of an organic hole transport layer and a light-emitting layer, or a three-layer structure consisting of an organic hole transport layer, a light-emitting layer, and an organic electron transport layer, Further, there may be a multilayer structure in which a hole injection layer is inserted between the transparent electrode and the hole transport layer, and an electron injection layer is inserted between the metal electrode and the electron transport layer. Then, the light generated in the light emitting functional layer is led out through the transparent electrode and the transparent substrate.

  The above-described organic EL element can be replaced with a configuration of a light emitting element having an electrically diode characteristic and a parasitic capacitance component coupled in parallel to the light emitting element. The organic EL element is a capacitive light emitting element. I can say that. In the organic EL element, when a light emission driving voltage is applied, first, a charge corresponding to the electric capacity of the element flows into the electrode as a displacement current and is accumulated. Subsequently, when a certain voltage specific to the element (light emission threshold voltage = Vth) is exceeded, a current starts to flow from one electrode (the anode side of the diode component) toward the light emitting functional layer, and light is emitted with an intensity proportional to the current. Then you can think.

  On the other hand, the current / brightness characteristics of organic EL elements are stable with respect to temperature changes, while the voltage / brightness characteristics are highly dependent on temperature changes, and the organic EL elements have received overcurrent. In general, constant current driving is performed for reasons such as severe deterioration and shortening the light emission life. As a display panel using such an organic EL element, a passive drive display panel in which elements are arranged in a matrix has already been put into practical use.

  FIG. 1 shows an example of a conventional passive matrix display panel and its driving circuit, which shows a form of cathode line scanning / anode line drive. That is, m data lines (hereinafter also referred to as anode lines) A1 to Am are arranged in the vertical direction, and n scanning lines (hereinafter also referred to as cathode lines) K1 to Kn are in the horizontal direction. Organic EL elements E11 to Emn shown as a parallel combination of diode and capacitor symbol marks are arranged in each crossed portion (total m × n locations) to constitute the display panel 1.

  Each EL element E11 to Emn constituting the pixel has one end (in the equivalent diode of the EL element) corresponding to each intersection position of the anode lines A1 to Am along the vertical direction and the cathode lines K1 to Kn along the horizontal direction. The anode terminal is connected to the anode line, and the other end (the cathode terminal in the equivalent diode of the EL element) is connected to the cathode line. Further, each anode line A1 to Am is connected to an anode line drive circuit 2 as a data driver, and each cathode line K1 to Kn is connected to and driven by a cathode line scanning circuit 3 as a scanning driver.

  The anode line drive circuit 2 includes constant current sources I1 to Im that operate using a drive voltage from a drive voltage source VH, and drive switches Sa1 to Sam, and the drive switches Sa1 to Sam include the above-described drive switches Sa1 to Sam. By being connected to the constant current sources I1 to Im, the currents from the constant current sources I1 to Im are used as light emission drive currents for the individual EL elements E11 to Emn arranged corresponding to the scanned cathode lines. Acts as supplied.

  In addition, the drive switches Sa1 to Sam have a non-light emitting potential (a ground potential GND which is a circuit reference potential in the form shown in FIG. 1) with respect to the individual EL elements E11 to Emn arranged corresponding to the cathode lines. It is configured so that it can be supplied.

  On the other hand, the cathode line scanning circuit 3 is provided with scanning switches Sk1 to Skn corresponding to the cathode lines K1 to Kn, and functions as a non-scanning selection potential and is mainly used to prevent crosstalk light emission. Either the reverse bias voltage from the source VM or the scanning selection potential (the ground potential GND in the embodiment shown in FIG. 1) can be supplied to the corresponding cathode line.

  A control signal is supplied to the anode line drive circuit 2 and the cathode line scanning circuit 3 from a light emission control circuit 4 including a CPU via a control bus, and the scanning is performed based on a video signal to be displayed. Switching operation of the switches Sk1 to Skn and the drive switches Sa1 to Sam is performed. Thus, the constant current sources I1 to Im are connected to the desired anode line while setting the cathode line to the ground potential at a predetermined cycle based on the video signal, and the EL elements E11 to Emn are selectively emitted. As a result, an image based on the video signal is displayed on the display panel 1.

  In the state shown in FIG. 1, the first cathode line K1 is set to the ground potential to be in a scanning state. At this time, each of the cathode lines K2 to Kn in the non-scanning state is supplied with the above-described reverse bias voltage source VM. A reverse bias voltage is applied. Here, when the forward voltage of the EL element in the scanning light emission state is Vf, each potential is set such that [(forward voltage Vf) − (reverse bias voltage VM)] <(light emission threshold voltage Vth). Therefore, each EL element connected to the intersection of the driven anode line and the cathode line not selected for scanning acts to prevent crosstalk light emission.

  FIG. 2 shows a light emission driving operation of the EL element including a reset period in which the amount of charge charged in the parasitic capacitance of each EL element is zero. In the description in this specification, the terms of lighting and light emission are mixed, but these have no particular meaning and are used as the same meaning. FIG. 2A shows a scanning synchronization signal. In this example, a reset period and a constant current driving period are set in synchronization with the scanning synchronization signal.

  2B and 2C show potentials applied to the lighting line and the non-lighting line in the anode line connected to the data driver (anode line drive circuit) 2 in each period. 2D and 2E show potentials applied to the scanning lines and non-scanning lines in the cathode lines connected to the scanning driver (cathode line scanning circuit) 3 in each period.

  In the reset period shown in FIG. 2, the drive switches Sa1 to Sam included in the data driver 2 are shown in FIG. 2B with respect to the anode line (lighting line) corresponding to the EL element to be driven for light emission. As shown, the ground potential GND is controlled to be supplied. In addition, the anode potential (non-lighting line) corresponding to the EL element that is not subject to light emission driving is controlled so as to supply the ground potential GND as shown in FIG.

  On the other hand, the scan driver 3 in the reset period uses the scan switches Sk1 to Skn provided therein to scan a cathode line (scan line) to be scanned and a cathode line (non-scan line) to be unscanned as shown in FIG. As shown in (D) and (E), the ground potential GND is controlled to be supplied. As a result, the anodes and the cathode electrodes of the organic EL elements E11 to Emn arranged on the display panel 1 are connected to the ground potential GND, which is a reset potential, respectively. A reset operation (GND-GND reset) to be zeroed is executed.

  Further, in the constant current driving period, which is a period during which the EL element can emit light, the anode lines (lighting lines) corresponding to the EL elements to be caused to emit light by the drive switches Sa1 to Sam are as shown in FIG. A constant current (CC) is supplied from the constant current sources I1 to Im. Further, as shown in FIG. 2C, the ground potential GND is set to the anode line (non-lighting line) corresponding to the EL element that is not subject to light emission.

  On the other hand, the cathode driver 3 in the constant current driving period has a scanning selection potential as shown in FIG. 2 (D) for the cathode lines (scanning lines) to be scanned by the scanning switches Sk1 to Skn provided therein. As shown in FIG. 2E, the reverse bias voltage VM, which is a non-scanning selection potential, is applied to the cathode potential (non-scanning line) set to the ground potential GND and excluded from scanning. .

  As a result, a lighting drive current is selectively supplied from the constant current sources I1 to Im to the EL elements that are connected to the scanning line and are to be lit, and turned on, and a reverse bias is applied to the non-scanned cathode line. By applying the voltage VM, each EL element connected to the intersection of the anode line to be lit and the cathode line that has not been selected for scanning is prevented from emitting crosstalk light.

Then, according to the gradation based on the light emission drive data from the light emission control circuit 4, a constant current (CC) supply period (light emission) as a light emission drive current applied to the EL elements to be controlled for light emission from the constant current sources I1 to Im. Period) is controlled. FIG. 2F shows an example of a voltage waveform in a cathode line (non-scanning line) that is not to be scanned. Passive drive display devices that are driven to emit light by the above-described operation are disclosed in Patent Document 1 and Patent Document 2 shown below.
JP 2002-366099 A JP 2005-003837 A

  By the way, in the passive drive type display device having the above-described configuration, depending on the lighting rate of the EL element, so-called shadowing (in which the emission luminance varies among the EL elements corresponding to the respective scanning lines having different lighting rates) It is known that lateral crosstalk) occurs. 3 and 4 illustrate the situation in which the above-described shadowing occurs.

  3A and 3B show a voltage application state to the EL element in the reset period and a voltage application state to the EL element in the constant current driving period according to the timing chart shown in FIG. In FIG. 3, the case where the lighting rate PN of the EL element is 100% is illustrated. FIG. 3 shows the state of potential supply to the EL elements corresponding to the first, second, and m-th anode lines and the first, second, and n-th cathode lines for the sake of space.

  In the reset period, as shown in FIG. 3A, all of the scan switches Sk1 to Skn and the drive switches Sa1 to Sam select the ground potential GND. As a result, the anodes and the cathode electrodes of the organic EL elements E11 to Emn arranged on the display panel 1 are connected to the ground potential GND which is a reset potential, respectively, and the charge in the parasitic capacitance of each EL element becomes zero. To be reset.

  On the other hand, in the constant current driving period, as shown in FIG. 3B, for example, the first scanning line K1 to be scanned and lit is set to the ground potential GND via the scanning switch Sk1, and the other scanning lines are scanned. The reverse bias voltage VM is applied via the switches Sk2 to Skn. At this time, all the drive switches Sa1 to Sam are connected to the constant current sources I1 to Im (lighting rate PN is 100%).

  According to the state shown in FIG. 3B, the lighting drive currents from the constant current sources I1 to Im are supplied to the EL elements connected to the first scanning line K1. At this time, the current flowing into the parasitic capacitance of the EL element not scanned from the reverse bias potential VM transiently flows into the anode side of the EL element to be lit through each anode line, and the current flows to the parasitic capacitance of the EL element to be lit. Charging is done rapidly. As a result, the light emission rise of the EL element to be lit is performed relatively quickly.

  Next, FIG. 4 shows an operation example when the lighting rate of the EL element is lowered. Note that the operation in the reset period at this time is the same as the example shown in FIG. The example shown in FIG. 4 shows an operation example in a constant current driving period in which the EL element corresponding to the mth anode line is lit. Also in this example, the first scanning line K1 to be scanned and lit is set to the ground potential GND via the scanning switch Sk1, and the reverse bias voltage VM is applied to the other scanning lines via the scanning switches Sk2 to Skn. The

  Here, the ground potential GND is applied to the anode and cathode terminals of the EL elements that are connected to the first scanning line K1 and are not to be lit, and the parasitic capacitance is maintained in a discharged state. The Therefore, it takes time to charge the non-scanned EL element from the reverse bias voltage VM to the cathode side, and the potential of the scan line is slowly increased as shown in FIG.

  Therefore, the flow of electric charge (the amount of sneak current) through the data line from the EL element that has not been scanned to the EL element that is the target of scanning lighting remains small. Therefore, in the above-described lighting driving operation in the above-described configuration, the upper right EL element shown in FIG. 4 in a state where the lighting rate is low is compared with the upper right EL element shown in FIG. 3B when the lighting rate is high. Shadowing that emits light with low brightness occurs.

  FIG. 5 schematically shows an example of shadowing generated by the above-described action. In the display pattern shown in FIG. 5, the “A” portion with double hatching indicates a region where the EL element is not lit, and the “B” portion and “C” portion indicate that the EL element is lit. Shows the area. As shown by “A” in FIG. 5, when the ratio of non-lighting elements is large for each scanning line (when the lighting rate is small), the region indicated by “B” is indicated by “C” due to the above-described action. “Dark lateral crosstalk” occurs in which light is emitted darker than the area.

  The above-described shadowing may be affected by the potential drop due to the resistance value on the scanning line side depending on factors such as the display pattern of the display panel and the time constant, and depending on the panel size. The portion indicated by “C” may generate “bright horizontal crosstalk” that emits light brighter than the portion indicated by “C”.

  Furthermore, it is known that the above-described shadowing becomes more pronounced as the setting of the dimmer value in the dimmer display for controlling the overall brightness of the display panel is lower. This is because, as the dimmer value is set lower, the light emission time of the EL element in one scanning period is shorter or the value of the drive current is smaller, so that the EL that is scanned through the parasitic capacitance of the EL element that is not scanned. This is because the contribution of charge flowing through the data line of the element is considered to be relatively high.

  The present invention solves the shadowing problem that occurs particularly when the lighting rate of each scanning line of the EL element is low as described above, and the shadowing problem that occurs more prominently as the setting of the dimmer value by the dimmer control is lower. The object of the present invention is to provide a driving device and a driving method for a light-emitting display panel, which can be reduced to a level that is not problematic in practical use.

  A preferred basic form of the drive device according to the present invention made to solve the above-described problems is, as described in claim 1, a plurality of scanning lines and a plurality of data lines intersecting each other, and each of the scanning lines and each of the scanning lines. A driving device for driving a passive matrix display panel having a light emitting element connected between each scanning line and each data line at the intersection of the data lines, A scan driver that applies a scan selection potential to a scan line to be scanned and a non-scan selection potential to a scan line that is not a scan target, and a data line that is a light emission drive target among the data lines A light driver that applies a non-light emission potential to a data line that is not a light emission driving target and a light emitting element connected to each of the scanning lines before light emission control is to be performed. A lighting rate acquisition means for obtaining a ratio PN of light emitting elements, and a light emission driving current is applied to a data line to be light emission driven after a non-scanning selection potential is applied to the scanning line not to be scanned. The period until application is configured to be controlled based on the ratio PN obtained by the lighting rate acquisition means.

  According to a preferred basic aspect of the driving method of the present invention made to solve the above-described problems, a plurality of scanning lines and a plurality of data lines intersecting each other, and each of the scanning lines as described in claim 7 And a driving method for driving the passive matrix display panel including a light emitting element connected between each scanning line and each data line at the intersection of each data line, A ratio PN of the light emitting elements to be controlled for light emission, a step of applying a non-scanning selection potential to the scanning line that is not to be scanned, and the non-scanning selection potential. The period from the application to the application of the light emission drive current to the data line that is the object of light emission drive is controlled based on the ratio PN, and the light emitting element that is the object of light emission drive is controlled. Characterized in that it executes the step of supplying a light emission drive current Te.

  Hereinafter, a drive device for a light-emitting display panel according to the present invention will be described based on the embodiments shown in the drawings. As described above, the drive device for a display panel according to the present invention applies to scanning lines that are not to be scanned. The basic concept is to variably control the period from the application of the non-scanning selection potential to the application of the light emission drive current to the data line to be light emission driven.

  That is, by executing the above-described control, the amount of current that flows from the reverse bias voltage source VM as the non-scanning selection potential into the EL element that is the lighting target (the above-described sneak current amount) is controlled, and as a result, the lighting target. The light emission luminance of the EL element can be controlled for each scanning line. This can prevent the occurrence of shadowing as described above.

  The driving device according to the present invention basically employs the same circuit configuration as that already described with reference to FIG. 1, and, as shown in FIG. 2, the reset period (described above) is synchronized with the scanning synchronization signal. GND-GND reset) and a constant current drive period are set. In the embodiments described below, parts that perform the same functions as the components shown in the respective drawings already described are denoted by the same reference numerals.

  FIG. 6 is a timing chart for explaining the lighting drive control executed in the drive device according to the present invention. FIGS. 6 (A) to (F) correspond to FIGS. 2 (A) to (F), respectively. To do. In the driving device according to the present invention, particularly as shown in FIG. 6B, in the constant current driving period after the reset period, as the light emission driving current supplied to the lighting line at least according to the lighting rate PN of the EL element. The application timing of the constant current CC is controlled so as to be controlled.

  That is, in the constant current driving period after the reset period, the reverse bias voltage VM as the non-scanning selection potential is applied to the non-scanning line as shown in FIG. After a period of t1 from the application timing of the non-scanning selection potential, the constant current CC as the light emission drive current is supplied to the lighting line as shown in FIG. 6B.

  FIG. 7 illustrates a state in the course of the period t1 with reference to the drawing corresponding to FIG. In this state, since all the lighting lines are set to the ground potential GND, the reverse bias voltage that flows into the anode line through the parasitic lines of the cathode lines K2 to Kn that are brought into the non-scanning state and the respective EL elements connected thereto. All currents from the VM flow to the ground GND side, which is a reference potential point, via the drive switches Sa1 to Sam.

  Therefore, when the period of t1 is set long (when the start timing of the light emission period in the constant current driving period is delayed), the scanning lighting target is connected via the parasitic capacitance of the EL element to be brought into the non-scanning state and the data line. The amount of current from the reverse bias voltage VM that wraps around the anode electrode side of the EL element becomes smaller. Therefore, the light emission luminance of the EL element to be scanned and turned on becomes small.

  When the period of t1 is set short (when the start timing of the light emission period in the constant current driving period is early), the scanning lighting target is connected via the parasitic capacitance of the EL element to be brought into the non-scanning state and the data line. The amount of current from the reverse bias voltage VM that wraps around the anode electrode side of the EL element becomes larger. Therefore, the light emission luminance of the EL element to be scanned and turned on increases.

  In short, when the period of t1 is short, the light emission luminance of the EL element that is the target of scanning lighting increases, and when the period of t1 is long, the light emission luminance of the EL element that is the target of scanning lighting decreases. Therefore, by using the above-described action to operate so as to control the period of t1 for each scanning line, the luminance variation of the EL element to be controlled for light emission generated for each scanning line depending on the lighting rate, that is, this. It is possible to suppress the shadowing caused by the above.

  8 suppresses the occurrence of shadowing by variably controlling the t1 according to a more detailed configuration corresponding to the light emission control circuit 4 and the lighting rate of the EL element, compared to the configuration shown in FIG. One form for implementing this invention provided with the structure which was made is shown. An analog video signal is supplied to the light emission control circuit 4 shown in FIG. That is, the analog video signal is supplied to the drive control circuit 11 and the analog / digital (A / D) conversion circuit 12 that constitute the light emission control circuit 4.

  The drive control circuit 11 generates a clock signal CK for the A / D conversion circuit 12 and a write signal W and a read signal R for the image memory 13 based on the horizontal synchronization signal and the vertical synchronization signal in the analog video signal. Further, the drive control circuit 11 outputs switching signals for the drive switches Sa1 to Sam in the data driver 2 shown in FIG. 8 based on the horizontal synchronization signal and the vertical synchronization signal, and scan switches Sk1 to Skn in the scan driver 3. The switching signal is output.

  The A / D conversion circuit 12 samples the input analog signal based on the clock signal supplied from the drive control circuit 11, converts it into image data corresponding to each pixel, and supplies it to the image memory 13. Acts like The image memory 13 operates so as to sequentially write the pixel data supplied from the A / D conversion circuit 12 to the image memory 13 in accordance with the write signal W from the drive control circuit 11.

  A frame memory is used as the image memory 13, and data for one screen (m columns, n rows) in the display panel 1 is written by the above-described writing operation. When the writing of data for one screen is completed, the memory 13 reads an image for every one row (one scan) from the first row to the nth row of the scanning lines by the read signal R supplied from the drive control circuit 11. Data is read out. The drive control circuit 11 operates so as to obtain the ratio (EL element lighting rate) PN of the EL elements to be controlled for light emission from the image data for each row. In other words, the drive control circuit 11 functions as an EL element lighting rate acquisition unit.

  Further, the drive control circuit 11 is configured to be supplied with dimmer control data from the dimmer setting means 15 so that the display panel 1 is displayed in the D (D = 1 to d) stage. It is configured. The dimmer setting means 15 may manually set the dimmer value, and a mobile device or the like may be configured to automatically set the dimmer value in response to external light.

  The drive control circuit 11, as one form, looks up the luminance correction data for each scanning line based on the lighting rate PN corresponding to each scanning line, in other words, the period control data corresponding to the period t1 described above. 14 and based on the period control data obtained from the lookup table 14, the switching operation of the drive switches Sa1 to Sam shown in FIG. 8 is controlled. The above-described operation is sequentially executed from the first row to the n-th row (N = 1 to n) of the scanning line in synchronization with the scanning of the scanning driver 3.

  Further, as another mode, the drive control circuit 11 scans the scanning line based on the lighting rate PN corresponding to each scanning line and the dimmer control data (D = 1 to d) set at this time. The brightness correction data for each time, that is, the period control data corresponding to the above-described period t1 is obtained from the lookup table 14, and based on the period control data obtained from the lookup table 14, the drive switches Sa1 to Sam shown in FIG. Controls the switching operation. The lookup table 14 used in this case is constructed in a map form (two-dimensional) from which the above-described period control data can be extracted from the lighting rate of the EL element and the dimmer control data.

  FIG. 9 illustrates an example in which the occurrence of shadowing is suppressed by the configuration shown in FIG. 8. The upper screen display shows a state in which shadowing is occurring, and the lower screen display is a shadowing occurrence. The state which suppressed generation | occurrence | production is shown typically. The upper screen display in FIG. 9 is the same as the example shown in FIG. 5 described above, and the “A” portion with double hatching indicates the area where the EL element is not lit, and “B” The “part” and the “C” part indicate regions where the EL elements are turned on. The above screen display example shows a state in which “dark horizontal crosstalk” occurs in which the area indicated by “B” emits darker than the area indicated by “C” even though the light emission driving data is the same. ing.

  In the case where “dark horizontal crosstalk” occurs as in the upper screen display in FIG. 9, “C” is set so that the luminance in the “C” region matches the luminance in the “B” region. By controlling the brightness of the region to be slightly lowered, the occurrence of shadowing can be substantially suppressed. This is achieved by controlling the period of t1 shown in FIG. 6B to be longer in the scanning of the “C” region, and in FIG. 6B in the scanning of the “B” region. By controlling so that the period of t1 shown is shortened, the occurrence of shadowing due to the “dark lateral crosstalk” can be suppressed.

  According to the lighting driving operation with the above-described configuration, the period control data is read from the table for each scanning line based on the lighting rate PN for each scanning line corresponding to one screen, and thereby the period is set for each scanning line. It is made to control t1. Thereby, as shown in the lower screen display in FIG. 9, the occurrence of shadowing can be effectively suppressed.

  When the period control data read from the table for each scanning line is based on the lighting rate PN for each scanning line corresponding to one screen and the dimmer control data set at this time, the EL element In addition to correcting the shadowing due to the lighting rate, it is possible to effectively suppress the occurrence of shadowing particularly at the time of low dimmer.

  In the case of executing time gradation in the configuration shown in FIG. 8, the period (light emission period) for applying the light emission drive current to the EL elements to be lit and displayed is determined based on the light emission drive data corresponding to each pixel. Is done. Accordingly, as described above, in correspondence with the control of the light emission start timing (the period t1) based on the period control data, the end timing of the light emission period is similarly extended to the period t1, as shown in FIG. 6B. It is necessary to execute.

  FIG. 10 illustrates another example in which the occurrence of shadowing is suppressed by the configuration shown in FIG. 8. The upper screen display shows a state where shadowing is occurring, and the lower screen display is a shadow. The state which suppressed generation | occurrence | production of ing is shown typically. In the example shown in FIG. 10, the lighting rate of the EL element is further reduced as compared with the example shown in FIG. 9, and the area indicated by “B” emits lighter than the area indicated by “C” even though the light emission driving data is the same. A state in which “bright horizontal crosstalk” occurs is schematically shown.

  In the above-described shadowing occurrence state, the brightness of the “C” area is controlled to be slightly increased so that the brightness of the “C” area shown in FIG. 10 matches the brightness of the “B” area. By doing so, the occurrence of shadowing can be substantially suppressed. For this, in the scanning of the “C” region, the period of t1 shown in FIG. 6B is controlled to be shorter, and in the scanning of the “B” region, FIG. 6B is used. By controlling the period of t1 to be longer, the occurrence of shadowing due to the “bright horizontal crosstalk” can be suppressed.

  According to the lighting driving operation with the above-described configuration, the period control data is read from the table for each scanning line based on the lighting rate PN for each scanning line corresponding to one screen, and thereby the period is set for each scanning line. It is made to control t1. Thereby, as shown in the lower screen display in FIG. 10, the occurrence of shadowing can be effectively suppressed.

  As in the example already described, the period control data read from the table for each scanning line is based on the lighting rate PN for each scanning line corresponding to one screen and the dimmer control data set at this time. In this case, in addition to the correction of the shadowing due to the lighting rate of the EL element, it is possible to effectively suppress the occurrence of the shadowing especially at the time of low dimmer.

  In the embodiment described above, an example in which an organic EL element is used as a light emitting element arranged in a display panel is shown. However, the same applies to the case where another element having a capacitance is used as the light emitting element. The effect of this can be obtained. In the embodiment described above, the non-scanning selection potential data is read from the lookup table based on the lighting rate of the EL element and the dimmer control data. You may be comprised so that it may obtain | require by.

It is a circuit block diagram which showed an example of the conventional passive matrix type | mold display panel and its drive circuit. 3 is a timing chart for explaining a lighting drive operation in the display panel shown in FIG. 1. It is a circuit block diagram explaining operation | movement when the lighting rate of the light emitting element according to the timing chart shown in FIG. 2 is high. FIG. 3 is a circuit configuration diagram illustrating an operation when a lighting rate of a light emitting element is low according to the timing chart shown in FIG. 2. It is the schematic diagram which showed the example which shadowing generate | occur | produces. It is a timing chart explaining the lighting drive operation | movement of the display panel concerning this invention. FIG. 7 is a circuit configuration diagram for explaining a part of the driving operation shown in FIG. 6. It is a circuit block diagram which showed the basic composition in the drive device concerning this invention. It is a schematic diagram explaining the correction example of the shadowing made by the structure shown in FIG. It is a schematic diagram explaining the other correction example of the shadowing made by the structure shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emission display panel 2 Data driver 3 Scan driver 4 Light emission control circuit 11 Drive control circuit (lighting rate acquisition means)
12 A / D conversion circuit 13 Image memory 14 Look-up table 15 Dimmer setting means A1 to Am Data line (anode line)
E11 to Emn Light emitting element (organic EL element)
I1 to Im lighting drive power supply (constant current source)
K1 to Kn Scan lines (cathode lines)
Sa1-Sam Drive switch Sk1-Skn Scan switch VH Drive voltage source VM Reverse bias voltage source (non-scanning selection power supply)

Claims (8)

Passive matrix type comprising a plurality of scanning lines and a plurality of data lines intersecting each other, and light emitting elements respectively connected between the scanning lines and the data lines at the intersections of the scanning lines and the data lines A driving device for driving a display panel to emit light,
A scanning driver that applies a scanning selection potential to a scanning line that is a scanning target among the scanning lines, and a non-scanning selection potential to a scanning line that is not a scanning target;
A data driver that applies a light emission drive current to a data line that is a light emission drive target among the data lines, and a non-light emission potential to a data line that is not a light emission drive target;
A lighting rate acquisition means for obtaining a ratio PN of the light emitting elements to be controlled for light emission among the light emitting elements connected to the scanning lines,
A period from when a non-scanning selection potential is applied to a scanning line that is not a scanning target to when a light emission driving current is applied to a data line that is a light emission driving target is obtained by the lighting rate acquisition unit. A drive device for a light-emitting display panel, which is configured to be controlled based on a ratio PN. Passive matrix type comprising a plurality of scanning lines and a plurality of data lines intersecting each other, and light emitting elements respectively connected between the scanning lines and the data lines at the intersections of the scanning lines and the data lines A driving device for driving a display panel to emit light,
A scanning driver that applies a scanning selection potential to a scanning line that is a scanning target among the scanning lines, and a non-scanning selection potential to a scanning line that is not a scanning target;
A data driver that applies a light emission drive current to a data line that is a light emission drive target among the data lines, and a non-light emission potential to a data line that is not a light emission drive target;
A lighting rate acquisition means for obtaining a ratio PN of the light emitting elements to be controlled for light emission among the light emitting elements connected to the scanning lines,
A dimmer control means for displaying the display panel in a D (D = 1 to d) stage.
A period from when a non-scanning selection potential is applied to a scanning line that is not a scanning target to when a light emission driving current is applied to a data line that is a light emission driving target is obtained by the lighting rate acquisition unit. A drive device for a light-emitting display panel, which is configured to be controlled based on a ratio PN and a dimmer control stage D in the dimmer control means.   One scanning period of the display panel includes a reset period in which both ends of all the light emitting elements are connected to a reset potential, and a light emitting period in which a light emission driving current is supplied to the light emitting elements to be controlled to emit light. 3. A drive device for a light emitting display panel according to claim 1 or 2, wherein:   Corresponding to the control of the period from when the non-scanning selection potential is applied to the scanning line that is not the scanning target to when the light emission driving current is applied to the data line that is the light emission driving target, 4. The drive device for a light emitting display panel according to claim 3, wherein the end timing is controlled.   5. The driving device of a light emitting display panel according to claim 1, wherein the scanning selection potential and the reset potential are the same potential.   6. The light-emitting display panel according to claim 1, wherein the light-emitting element is an organic EL light-emitting element having an organic light-emitting functional layer composed of one or more layers between opposing electrodes. Drive device. Passive matrix type comprising a plurality of scanning lines and a plurality of data lines intersecting each other, and light emitting elements respectively connected between the scanning lines and the data lines at the intersections of the scanning lines and the data lines A driving method for driving a display panel to emit light,
A step of obtaining a ratio PN of the light emitting elements to be controlled for light emission among the light emitting elements connected to the scanning lines;
Applying a non-scanning selection potential to the scanning lines that are not to be scanned;
The period from the application of the non-scanning selection potential to the application of the light emission drive current to the data line to be light emission driven is controlled based on the ratio PN, and the light emission element to be the light emission drive target is controlled Supplying a light emission driving current,
A method for driving a light-emitting display panel, comprising: Passive matrix type comprising a plurality of scanning lines and a plurality of data lines intersecting each other, and light emitting elements respectively connected between the scanning lines and the data lines at the intersections of the scanning lines and the data lines A driving method for driving a display panel to emit light,
A step of obtaining a ratio PN of the light emitting elements to be controlled for light emission among the light emitting elements connected to each scanning line, and data for dimmer control for performing dimmer display on the display panel in a D (D = 1 to d) stage. When,
Applying a non-scanning selection potential to the scanning lines that are not to be scanned;
A period from the application of the non-scanning selection potential to the application of the light emission drive current to the data line to be light emission driven is controlled based on the ratio PN and the data of the dimmer control, and the light emission drive target Supplying a light emission driving current to the light emitting element,
A method for driving a light-emitting display panel, comprising:

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