JP2002366099A - Driving device of capacitive light emitting display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption of a driving device of a light emitting display panel. SOLUTION: A light emitting display panel 1 is composed of organic EL display elements OEL. In a non-scanning state, reverse bias voltages are applied to the elements OEL by a reverse bias voltage generating circuit 5 to prevent cross talk light emission. Moreover, a return voltage from an anode line driving circuit 2 is superimposed onto the circuit 5 side through parasitic capacitors Cp in the elements OEL and the reverse bias voltages are shifted up. In a DC-DC converter 6 that supplies a driving voltage to the circuit 2, the driving voltage to be supplied to the circuit 2 is controlled by utilizing the voltage information being shifted up. Thus, an output voltage which is nearly capable of securing a regulated current characteristic of constant current circuits I1 to In arranged for the circuit 2 is outputted from the converter 6 and the power consumption is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a technique for driving a capacitive light emitting element such as an (electroluminescence) element to emit light, and more particularly to a technique for driving a display panel formed by arranging organic EL elements in a capacitive light emitting display panel capable of reducing power loss. It relates to a driving device.

[0002]

2. Description of the Related Art An organic EL display has been attracting attention as a display which can replace a liquid crystal display with low power consumption, high display quality, and be thin. This is because, by using an organic compound that can be expected to have good light-emitting characteristics in the light-emitting layer of an EL element used in an EL display, high efficiency and long service life that can withstand practical use have been advanced. is there.

An organic EL device can be electrically represented by an equivalent circuit as shown in FIG. That is, the organic EL
The element can be replaced with a configuration including a diode component E and a parasitic capacitance component Cp coupled in parallel with the diode component, and the organic EL element is considered to be a capacitive light emitting element. 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 an electrode as a displacement current and is accumulated. Subsequently, when the voltage exceeds a certain voltage (light emission threshold = Vth) unique to the element, a current starts to flow from the electrode (the anode side of the diode component E) to the organic layer constituting the light emitting layer, and light is emitted at an intensity proportional to this current. Then you can think.

FIG. 5 shows the static light emission characteristics of such an organic EL device. According to this, as shown in FIG. 5A, when the driving voltage (V) is equal to or higher than the light emission threshold voltage (Vth), the current (I) rapidly flows to emit light. In other words, if the applied drive voltage is equal to or lower than the light emission threshold voltage, almost no drive current flows to the EL element after charging the parasitic capacitance, and the EL element does not emit light. Then, in a light emission enabling region where the drive voltage (V) is equal to or higher than the light emission threshold voltage, as shown in FIG. I have. Therefore, as shown in FIG. 5 (c), the luminance characteristics of the EL element in a light emitting area where the threshold voltage is higher than the threshold voltage, the light emitting luminance (L) increases as the voltage (V) applied thereto increases. It has the property of increasing.

On the other hand, the above-mentioned organic EL device also has a characteristic that the physical properties of the device change over a long period of use and the resistance value of the device itself increases. For this reason, organic EL
In the element, as shown in FIG. 5A, the VI characteristic changes in the direction indicated by the arrow (the characteristic indicated by the broken line) with the elapse of the actual use time, and thus the luminance characteristic also deteriorates.

Further, it is also known that the luminance characteristics of the organic EL element vary depending on the temperature, as shown by a broken line in FIG. 5C. In other words, the EL element has a characteristic that, in a light-emission-possible region in which the light-emitting threshold voltage is higher than the above-described light-emitting threshold voltage, as the value of the voltage (V) applied thereto increases, the light-emitting luminance (L) increases. The light emission threshold voltage becomes smaller. Therefore, the EL
The element is capable of emitting light with a lower applied voltage as the temperature rises, and has a temperature dependence of luminance such that the element is bright at a high temperature and dark at a low temperature even when the same applied voltage at which the element can emit light is applied.

As a method of driving a display panel constituted by arranging a plurality of organic EL elements, a simple matrix driving method is applicable. FIG. 6 shows an example of a simple matrix display panel and its driving device. There are two methods of driving the organic EL element in this simple matrix drive system, namely, a cathode line scan / anode line drive and an anode line scan / a cathode line drive. The configuration shown in FIG. 4 shows a form of a drive. That is, the anode lines A1 to An as n drive lines are vertically arranged, and the cathode lines B as m scan lines are
1 to Bm are arranged in the horizontal direction, and an organic EL element OEL indicated by a diode symbol mark is arranged at each intersecting portion (a total of n × m places) to constitute the display panel 1.

Each of the EL elements constituting the pixel is arranged in a lattice pattern, and has one end corresponding to the intersection between the anode lines A1 to An extending along the vertical direction and the cathode lines B1 to Bm extending along the horizontal direction (as described above). The anode terminal of the diode component E of the equivalent circuit is connected to the anode line, and the other end (the cathode terminal of the diode component E of the equivalent circuit described above) is connected to the cathode line. The anode line is connected to the anode line drive circuit 2 and the cathode line is connected to and driven by the cathode line scanning circuit 3.

The cathode line scanning circuit 3 includes scanning switches SY1 to SYm corresponding to the respective cathode scanning lines B1 to Bm. The reverse bias voltage from the reverse bias voltage generating circuit 5 for preventing crosstalk emission is provided. Either (VM) or the ground potential as a reference potential point acts to connect to the corresponding cathode scan line. The anode line drive circuit 2 has a constant current circuit I as a constant current source for supplying a drive current to each EL element through each anode line.
1 to In and drive switches SX1 to SXn are provided.

The drive switches SX1 to SXn operate to connect either the current from the constant current circuits I1 to In or the ground potential to the corresponding anode line. Therefore, the drive switches SX1 to SX
By connecting Xn to the constant current circuit side, the current from the constant current circuits I1 to In acts to be supplied to the individual EL elements arranged corresponding to the cathode scanning lines.

It is also possible to use a drive source such as a constant voltage circuit in place of the above constant current circuit. However, while the current / luminance characteristics of the EL element are stable against temperature changes, In general, a constant current circuit is used as a drive source as shown in the figure because the luminance characteristics are unstable with respect to temperature changes and the element is prevented from deteriorating due to overcurrent. It is common.

A control bus is connected to the anode line drive circuit 2 and the cathode line scan circuit 3 from a light emission control circuit (not shown). The scan switches SY1 to SYm and the drive switches are controlled based on an image signal to be displayed. SX1 to SXn are operated. Thus, the constant current circuit is connected to a desired anode line while setting the cathode scanning line to the reference potential at a predetermined cycle based on the image signal. Thereby, each of the light emitting elements selectively emits light, and an image based on the image signal is reproduced on the display panel 1.

Each of the constant current circuits I1 to In in the anode line drive circuit 2 has a DC output (drive voltage = VCOM) provided from a booster circuit 6 by a DC-DC converter.
) Is supplied. In addition, the booster circuit 6 using the DC-DC converter described below
Although a DC output is generated by WM control (variable control of pulse width), PFM control (variable control of pulse synchronization) can also be used.

This DC-DC converter is configured such that the PWM wave output from the switching regulator circuit 11 turns on the npn transistor Q1 as a switching element at a predetermined duty cycle. That is, the power energy from the DC voltage source 12 is accumulated in the inductor L1 by the on operation of the transistor Q1, and the power
The power energy stored in the inductor is stored in the capacitor C1 via the diode D1. Then, by repeating the on / off operation of the transistor Q1, the boosted DC output can be obtained as the terminal voltage of the capacitor C1.

The DC output voltage is connected to resistors R1 and R2.
Is divided by the switching regulator circuit 11
Is supplied to the error amplifier 14 by the operational amplifier at
This error amplifier 14 compares the voltage with the reference voltage Vref. This comparison output (error output) is supplied to the PWM circuit 15, and by controlling the duty of the signal wave provided from the oscillator 16, feedback control is performed so that the output voltage is maintained at a predetermined constant voltage. Therefore, the output voltage Vout obtained by the DC-DC converter 6 can be expressed as follows.

[0016]

(Equation 1)

On the other hand, the reverse bias voltage generating circuit 5 used for preventing the crosstalk light emission is constituted by a voltage dividing circuit for dividing the output voltage Vout. That is, this voltage dividing circuit includes resistors R3 and R4 and an npn transistor Q2 functioning as an emitter follower. Therefore, if the base-emitter voltage of the transistor Q2 is expressed as Vbe, the reverse bias voltage VM obtained by this voltage dividing circuit is obtained.
Can be shown as follows:

[0018]

(Equation 2)

[0019]

In the driving apparatus for a light emitting display panel having the above-described structure, the output voltage supplied from the DC-DC converter 6 applied to each of the constant current circuits I1 to In in the anode line drive circuit 2. Is
The above-described switching regulator using, for example, a PWM method is controlled so that the output voltage (constant voltage) is always substantially constant. In this case, the output voltage provided from the DC-DC converter 6 is set high considering the following factors so that the constant current characteristics of the constant current circuit in the anode line drive circuit 2 can be sufficiently secured. I have to do it.

That is, the elements include, for example, a constant tolerance of each circuit component constituting the above-described switching regulator, a variation in a voltage drop amount in each constant current circuit, and a maximum luminance level of each organic EL element. FIG. 5 shows the voltage drop due to the panel wiring resistance.
5A, the forward voltage rise due to the temporal change of the EL element, and the forward voltage fluctuation due to the temperature dependence of the EL element described based on FIG. Minute). In the conventional light emitting display panel driving device, the constant current characteristics of the constant current circuits I1 to In can be sufficiently secured even when these components act synergistically. The output voltage provided from the DC-DC converter 6 is set higher.

However, as described above, DC-DC
When the output voltage provided by the converter is set higher, an excessive power loss often accompanies, for example, when this is adopted in a portable terminal or the like,
This not only promotes battery consumption but also results in heat generation due to power loss. That is, when the output voltage is set higher, the voltage drop in each of the constant current circuits I1 to In in the anode line drive circuit 2 increases, and the power loss increases in proportion thereto.
Therefore, the heat generated thereby applies stress to the organic EL element and the peripheral circuit components, and causes a problem such as shortening the life of the EL element.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a capacitive light emitting display panel capable of effectively suppressing the above-described power loss and reducing the degree of adverse effects due to heat generation. It is an object to provide a driving device.

[0023]

To achieve the above object, a driving apparatus for a light emitting display panel according to the present invention comprises: a plurality of drive lines and a plurality of scan lines which intersect each other; A driving device for a light-emitting display panel comprising a plurality of drive lines and a capacitive light-emitting element connected between each of the scanning lines at a plurality of intersection positions of the scanning lines, wherein one of the scanning lines is set to a reference potential. In the state where the light emitting element is driven to emit light, the light emitting drive voltage applied to the drive line is changed corresponding to the voltage value generated on the scanning line via the parasitic capacitance of the light emitting element in the non-scanning state. It has features.

In this case, preferably, a constant current source is arranged in each of the drive lines, and a constant current is supplied to each light emitting element in a scanning state via the constant current source. The drive voltage supplied to the constant current source arranged in each of the drive lines is configured to change in accordance with a voltage value generated in the scan line via the parasitic capacitance of the light emitting element in the non-scan state.

In a preferred embodiment,
In a state where one of the scanning lines is set to the reference potential and the light emitting element is driven to emit light, a reverse bias voltage is applied to the light emitting element in a non-scanning state via a scanning line, and the reverse bias is applied. The driving voltage supplied to the constant current source is changed according to the voltage value superimposed on the voltage.

In this case, preferably, the reverse bias voltage generating circuit for generating the reverse bias voltage includes a Zener diode, and is configured to obtain the reverse bias voltage based on the Zener voltage generated by the Zener diode.

On the other hand, in an embodiment of the driving device according to the present invention, there is provided a peak hold circuit for holding a peak of the voltage value generated on a scanning line via a parasitic capacitance of a light emitting element in a non-scanning state, In some cases, the driving voltage supplied to the constant current source is changed based on a peak voltage value held by a peak hold circuit.

In a preferred embodiment of the driving device according to the present invention, the driving voltage supplied to the constant current source is supplied from a DC-DC boosting circuit, and the DC-DC A feedback circuit is configured in which the drive voltage obtained from the booster circuit is controlled according to the voltage value. Each of the above-described configurations can be suitably used for a driving device of a light-emitting display panel using organic electroluminescence as a light-emitting element.

According to the driving apparatus of the light emitting display panel having the above-described configuration, the voltage value generated on the scanning line via the parasitic capacitance of the light emitting element in the non-scanning state is used. Acts to change the power. That is, a reverse bias voltage is normally applied to the scanning line corresponding to the light emitting element in the non-scanning state in order to prevent crosstalk light emission. The generation circuit that generates the reverse bias voltage is configured to output the reverse bias voltage via the voltage buffer circuit, and the voltage buffer circuit has an output impedance. Therefore, a voltage value corresponding to a forward voltage of each light emitting element is substantially superimposed on the reverse bias voltage via the parasitic capacitance, and the reverse bias voltage is shifted up.

On the other hand, a configuration in which each of the light emitting elements is driven to light through a constant current circuit arranged in each drive line is preferably used. The driving voltage applied to the constant current circuit is such that a reverse bias voltage is shifted. It is controlled so as to increase in accordance with the voltage value to be increased. As a result, it is possible to eliminate the necessity of setting the drive voltage applied to the constant current circuit to a higher constant voltage by taking useless margins accumulated according to each element as in the above-described conventional drive device. .

Therefore, it is possible to control the voltage drop in the constant current circuit for driving each light-emitting element to be minimized, thereby effectively reducing the power loss generated in the constant current circuit. Can be suppressed.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a driving apparatus for a light emitting display panel according to the present invention will be described below with reference to the drawings. FIG. 1 shows the basic configuration. In FIG. 1, portions corresponding to the respective components of FIG. 6 already described are denoted by the same reference numerals, and therefore, detailed description thereof will be omitted. In the configuration shown in FIG. 1, the reverse bias voltage generating circuit 5 includes a constant current circuit 18 driven by a driving voltage generated by the DC-DC converter 6, and a zener diode ZD1 driven by the constant current circuit. It is composed of The Zener voltage generated in the Zener diode ZD1 is supplied to the non-scanning cathode scanning line via the voltage buffer circuit 19.

Each organic EL element O constituting the display panel 1
The EL has the parasitic capacitance Cp as described above. Therefore, the reverse bias voltage from the reverse bias voltage generating circuit 5 is charged to the parasitic capacitance Cp of each EL element at the beginning. On the other hand, a constant current is supplied to each EL element from each of the constant current circuits I1 to In in the anode line drive circuit 2. When the forward voltage of each EL element exceeds the set reverse bias voltage,
A current flows toward the cathode scanning line via the parasitic capacitance Cp.

Incidentally, the above-described voltage buffer circuit 19
Has an output impedance as indicated by the reference symbol R6. Therefore, the current flowing toward the cathode scanning line side through each parasitic capacitance Cp causes the output of the voltage buffer circuit 19 via the output impedance R6. At the end, a voltage peak value for shifting up the reverse bias voltage is generated. Voltage peak value for shifting up the reverse bias voltage (hereinafter, also referred to as return voltage)
Corresponds substantially to the forward voltage of the EL element.

In the embodiment shown in FIG.
Between the resistors R1 and R2 in the DC converter 6, p
An np transistor Q3 is inserted, and the base of the transistor is connected to an output terminal of the voltage buffer circuit 19 via an output impedance R6.
Therefore, a shift-up voltage in which a return voltage is superimposed on the reverse bias voltage is applied to the base of the transistor Q3. The transistor Q3 functions as a current buffer, and the transistor Q3
Is approximately equal to the collector current.

Therefore, the voltage between the emitter and the base of the transistor Q3 (=
0.65 V) is superimposed and applied to the resistor R2 side, so that the output voltage of the DC-DC converter 6 rises in accordance with the shifted voltage. The output voltage of the DC-DC converter 6 is fed back through a switching regulator circuit 11 using PWM, and therefore, the resistors R2 and R1
And the parameter of the reference voltage Vref, D
The output voltage of C-DC converter 6 is determined.

FIG. 2 illustrates a specific example of a constant current circuit constituting the reverse bias voltage generation circuit 5 in the configuration of the drive circuit shown in FIG. This constant current circuit
It is composed of transistors Q4 and Q5 and resistors R8 to R11. That is, the emitter of the transistor Q4 is connected to the output voltage line of the DC-DC converter 6, and its collector is connected to the reference potential point via the resistor R11. The base of the transistor Q5 is connected to the collector of the transistor Q4, and the emitter is connected to the output voltage line of the converter 6 via the resistor R8. Further, the collector is connected to the Zener diode ZD1 to form a constant current output terminal. On the other hand, resistors R9 and R10 are connected between the emitter and base of the transistor Q5.
Is connected to the base of the transistor Q4.

In the above-described circuit configuration, it is desirable that the current amplification factor hfe of each of the transistors Q4 and Q5 be set so as to satisfy the relationship of R9 = R10 = R8 × 10 under the condition of 80 or more. In addition, Zener diode ZD1
Is the zener voltage of Vzd, and the base of each transistor
Assuming that the emitter-to-emitter voltage is 0.65 V, the resistor R11
Is R11 ≦ (Vzd−1.5 × 0.65) / [0.65 / (R9 + R1
0)].
When the above conditions are set, each transistor Q4, Q5
, The voltage between the emitter and the base is 0.
Since the voltage is locked at 65V, the voltage drop at the resistor R8 can be reduced to about 0.3V. The emitter-collector saturation voltage of the transistor Q5 is 0.1 V
It is about. Therefore, in the circuit configuration described above, a constant current circuit can be configured with a minimum saturation voltage of about 0.4V.

Here, the emitter potential Ve of the emitter follower transistor Q6 forming the voltage buffer circuit is
Although it can be expressed as Ve = Vzd−0.65, a return voltage that substantially shifts up the reverse bias voltage described above is added, and when this voltage value is Vβ,
The emitter potential Ve of the transistor Q6 can be expressed as follows.

[0040]

(Equation 3)

The peak value of Ve at this time is substantially equal to the forward lighting voltage of each organic EL element. And FIG.
The output voltage Vout1 obtained from the DC-DC converter 6 having the circuit configuration shown in FIG.

[0042]

(Equation 4)

In the embodiment shown in FIG. 2,
A resistor R15 is inserted in the feedback system of the DC-DC converter 6, so that an unstable operation that can occur in the converter 6 via the feedback system can be suppressed.

As is clear from the above description, the voltage value Vβ for shifting up the reverse bias voltage is always added to the output voltage Vout1 obtained from the DC-DC converter 6 having the circuit configuration shown in FIG. Output in the state of The voltage value Vβ corresponds to the forward lighting voltage of the EL element as described above, and acts so that the output voltage Vout1 obtained from the DC-DC converter 6 changes according to the forward voltage of the EL element. . Therefore, as in the conventional driving device shown in FIG. 6, it is possible to eliminate the necessity of setting a higher output voltage of the DC-DC converter 6 by adding a useless margin accumulated according to each element. .

In other words, it is possible to control the voltage drop in the constant current circuits I1 to In for driving each light emitting element to a minimum, thereby effectively suppressing the power loss generated in the constant current circuits. be able to. Also,
Output voltage Vout1 obtained from DC-DC converter 6
Can follow the increase in the forward voltage of the EL element due to, for example, a change with time, and can also follow the change in the forward voltage due to the temperature dependency of the EL element.

In the embodiment shown in FIGS. 1 and 2, the reverse bias voltage generation circuit 5 is a DC-DC
The constant current circuit is driven by the output voltage obtained from the converter 6, and a reverse bias voltage is generated based on the Zener voltage by the Zener diode.
By using the constant current circuit in this way, DC-D
The variation of the output voltage obtained from the C converter 6 can be blocked, and a stable reverse bias voltage can be provided.

That is, the reverse bias voltage generation circuit 5
For simplicity, it is conceivable to use resistance dividing means. However, in the above-described embodiment, when the resistance dividing means is employed as the reverse bias voltage generation circuit 5, when the reverse bias voltage is shifted up through each parasitic capacitance Cp, the converter 6 responds accordingly.
Is also shifted up, so that the reverse bias voltage obtained by the resistance dividing means also acts to shift up. That is, a positive feedback loop is formed via the reverse bias voltage generation circuit, and the DC-DC converter 6
A phenomenon occurs in which the obtained output voltage always sticks to a high voltage.

For the above reasons, in the embodiment shown in FIGS. 1 and 2 in which the drive voltage output from converter 6 operates so as to fluctuate based on the upshift of the reverse bias voltage, the reverse bias is applied. It is desirable that the voltage generation circuit 5 employs a constant current circuit.

Next, FIG. 3 shows another embodiment of the driving device according to the present invention. In FIG. 3, portions corresponding to the components already described are denoted by the same reference numerals, and therefore, detailed description thereof will be omitted. The configuration shown in FIG. 3 is characterized in that a peak hold circuit for holding a peak value of a return voltage for shifting up a reverse bias voltage is provided. The peak value held by the peak hold circuit is D
The transistor Q3 constituting the C-DC converter 6
It is configured to be supplied to a base.

That is, the npn transistor Q7 is connected to the emitter of the voltage buffer transistor Q6 in the reverse bias voltage generation circuit 5 by forming a peak hold circuit.
The base is connected. The collector of the transistor Q7 is connected to the output line of the DC-DC converter 6, and the emitter of the transistor Q7 is connected to a reference potential point via a resistor R17. And
A capacitor C3 for peak hold is connected between the emitter and a reference potential point, and a terminal voltage of the capacitor C3 is supplied to a base of the transistor Q3 constituting the DC-DC converter 6. ing.

In the above configuration, actually, the resistor R12 shown as the output impedance of the voltage buffer in the reverse bias voltage generating circuit 5 and the resistor R12 shown as the impedance in the cathode scanning path.
There are thirteen. Also, although not shown in FIG.
A reset switch for periodically discharging the electric charge of the capacitor C3 constituting the peak hold circuit is provided. The cathode line scanning circuit 3 discharges the electric charge of the capacitor C3 as needed at the moment when the cathode scanning is switched. Be composed.

According to the above configuration, the peak value of the return voltage for shifting up the reverse bias voltage is determined by the capacitor C3.
Is charged and held. This hold voltage (peak voltage) is supplied to the base of the transistor Q3 which functions as a current buffer. Therefore, the output voltage Vout2 obtained from the DC-DC converter 6 having the circuit configuration shown in FIG. 3 can be expressed as follows.

[0053]

(Equation 5)

That is, the DC in the configuration shown in FIG.
The output voltage Vout2 obtained from the DC converter 6 is output-controlled with a voltage drop of 0.65 V as compared with the output voltage Vout1 (Equation 4) in the configuration shown in FIG. This is due to a drop due to the base-emitter voltage Vbe in the transistor Q7 constituting the peak hold circuit.

As shown in FIG. 3, when the voltage value shifted up by the return voltage is peak-held by the peak hold circuit, the capacity formed on the display panel 1 is small, and the time of one scan is reduced. Even if it ’s long,
A stable voltage can be supplied to the base of the transistor Q3. Then, the DC-DC converter can output an optimized output voltage to the extent that the constant current characteristics of the constant current circuits I1 to In arranged in the anode line drive circuit 2 can always be ensured. This can contribute to reducing the loss.

In each of the above-described embodiments, the DC-DC converter constitutes a switching regulator based on a PWM (pulse width modulation) system in any case, but adopts a PFM (pulse frequency modulation) system. Alternatively, for example, a drive voltage generating means using a transformer coupling may be employed.

[0057]

As apparent from the above description, according to the light emitting display panel driving apparatus of the present invention, the voltage value generated on the scanning line via the parasitic capacitance of the light emitting element in the non-scanning state corresponds to: Since the configuration is such that the light emission drive power given to the drive line is changed, for example, a voltage drop in a constant current circuit arranged in the anode line drive circuit can be reduced as much as possible, and therefore, power loss can be reduced. it can.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing an embodiment of a driving device for a capacitive light emitting display panel according to the present invention.

FIG. 2 is a connection diagram showing a specific configuration of a reverse bias voltage generation circuit in the driving device shown in FIG.

FIG. 3 is a connection diagram showing another embodiment of the driving device according to the present invention.

FIG. 4 is a diagram showing an equivalent circuit of the organic EL element.

FIG. 5 is a characteristic diagram showing various characteristics of the organic EL element.

FIG. 6 is a connection diagram showing an example of a conventional driving device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light emitting display panel 2 anode line drive circuit 3 cathode line scanning circuit 4 light emission control circuit 5 reverse bias voltage generation circuit 6 DC-DC converter (boost circuit) 11 switching regulator circuit 12 DC voltage source 14 error amplifier 15 PWM circuit 16 oscillator A1- An Anode (drive) line B1 to Bm Cathode (scan) line D1 Diode I1 to In Constant current circuit (constant current source) L1 Inductor OEL Organic EL element Q1 to Q7 Transistor R1 to R17 Resistance SX1 to SXn Drive switch SY1 to SYn Scan Switch Vref Reference voltage ZD1 Zener diode

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Okuyama 4- 3146-7, Yawatawara, Yonezawa-shi, Yamagata Prefecture Inside Yonezawa Plant, Tohoku Pioneer Co., Ltd. 7 Yonezawa Plant, Tohoku Pioneer Co., Ltd. (72) Gen Suzuki 4-146, Yawatahara, Yonezawa City, Yamagata Prefecture 7 F-term (reference) in Yonezawa Plant, Tohoku Pioneer Co., Ltd. 3K007 AB02 AB05 AB11 BA06 DA01 DB03 EB00 GA01 GA04 5C080 AA06 BB05 DD26 EE25 FF12 JJ02 JJ05

Claims (7)

[Claims] 1. A capacitive light emitting element connected between each drive line and each scan line at a plurality of drive lines and a plurality of scan lines intersecting each other and at a plurality of intersections between the drive lines and the scan lines. A driving device for a light-emitting display panel, comprising: setting one of the scanning lines to a reference potential to drive the light-emitting element to emit light; A driving apparatus for a capacitive light emitting display panel, wherein a light emission drive voltage applied to the drive line is changed according to a generated voltage value. 2. A constant current source is disposed on each of the drive lines, and a constant current is supplied to each light emitting element in a scanning state via the constant current source. 2. The device according to claim 1, wherein the driving voltage supplied to the constant current source arranged on the line changes according to a voltage value generated on the scanning line via a parasitic capacitance of the light emitting element in the non-scanning state. Drive device for capacitive light emitting display panel. 3. A configuration in which a reverse bias voltage is applied to a light emitting element in a non-scanning state via a scanning line in a state where one of the scanning lines is set to a reference potential and the light emitting element is driven to emit light. 3. The driving device for a capacitive light emitting display panel according to claim 2, wherein the driving voltage supplied to the constant current source is changed according to the voltage value superimposed on the reverse bias voltage. 4. The device according to claim 3, wherein the reverse bias voltage generating circuit for generating the reverse bias voltage includes a Zener diode, and is configured to obtain the reverse bias voltage based on the Zener voltage generated by the Zener diode. Drive device for capacitive light emitting display panel. 5. A peak hold circuit for holding a peak of the voltage value generated on a scanning line via a parasitic capacitance of a light emitting element in a non-scan state, and based on a peak voltage value held by the peak hold circuit. 4. The driving device for a capacitive light emitting display panel according to claim 2, wherein the driving voltage supplied to the constant current source is changed. 6. A driving voltage supplied to the constant current source,
The drive voltage supplied from the DC-DC booster circuit and obtained from the DC-DC booster circuit is:
4. The driving device for a capacitive light emitting display panel according to claim 2, wherein a feedback circuit controlled according to the voltage value is configured. 7. The driving device for a light emitting display panel according to claim 1, wherein the light emitting element is an organic electroluminescence.