JPH03175489A - Driving device for el display panel - Google Patents

Abstract

PURPOSE:To prevent the EL display panel and a driving device from breaking by stopping the display driving of the EL display panel when the cycle of a horizontal synchronizing signal becomes short owing to the trouble of equipment. CONSTITUTION:A control part 80 and a discrimination part 90 are provided and the discrimination part 90 decides the horizontal synchronizing signal which is inputted from outside, and a constant-cycle reference signal from the control part 80 and its length. When the cycle of the horizontal synchronizing signal is short, namely, when a voltage is applied before the discharging of charges injected into picture elements ends, the discrimination part 90 sends a stop signal for stopping the display driving of driving parts 30 and 40 to the control part 80 and the display driving of the EL display part 10 is all stopped with the stop signal. Consequently, when excessive charges are injected into the picture elements, the driving display of the EL display panel is stopped and the EL display panel and driving device are prevented from breaking.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an EL display panel device.

(Prior Art) Normally, an EL display panel is driven by line sequential driving in which each line is driven, and the driving period of one line is the same as the period of a horizontal synchronizing signal. Furthermore, in order to cause an EL display panel to emit light, it is necessary to apply a voltage equal to or higher than a light emission threshold to each pixel to inject charge, and to discharge the charge injected into the pixel for the next light emission.

By the way, an EL display panel has the property of a capacitive load, and it takes a certain amount of time for charge injection and discharge, so when driving an EL display panel, the period of the horizontal synchronization signal may cause noise or equipment trouble. If the voltage is shortened for some reason, a voltage is applied to the pixel while the charge injected during the previous drive remains, and as a result, excess charge is injected into the pixel, causing damage to the EL display panel and drive driver. destruction may occur.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned drawbacks of the prior art, and its purpose is to provide a drive device that does not cause destruction of the EL display panel and the drive device.

(Means for Solving the Problems) The present inventors have conducted extensive studies to solve the above problems, and have found that when excessive charges are injected into pixels, E
The present invention has been completed based on the discovery that the EL display panel and the drive device are not destroyed by stopping the display drive of the L display panel. That is, the present invention provides a driving device for an EL display panel having a double insulation structure in which a light emitting layer is sandwiched between insulating layers, which includes a control section and a determination section,
The determination unit determines the length of the horizontal synchronization signal input from the outside and the reference signal with a constant period emitted from the control control unit, and if the period of the horizontal synchronization signal is shorter than the period of the reference signal, the driving device This driving device is characterized in that it sends a stop signal to a control unit to stop display driving.

(Function) The driving device of the present invention has the above configuration, and can be driven when the period of the horizontal synchronizing signal is short, that is, when the voltage is applied before the discharge of the charge injected into the pixel is completed. A stop signal for stopping the display driving of the device is sent from the determining section to the control section, and this stop signal stops all display driving of the EL display panel. As a result, when excessive charge is injected into a pixel, the driving display of the EL display panel is stopped, and the EL display panel and the driving device are not destroyed.

(Example) The present invention will be described below based on the drawings, but the present invention is not limited thereto.

FIG. 1 is a diagram showing an example of the configuration of a driving device for an EL display panel according to the present invention. In the figure, IO is an EL display panel, 20 is a data side driver connected to the data side electrode of the EL display panel, 30 is a scan side driver connected to the scan side electrode of the EL display panel, and 40 is the scan side driver 30. A high voltage switching circuit that provides high voltage pulses; 50 is a high voltage power supply section that generates a high voltage that is applied to the high voltage switching circuit 40;
0 is a change applied to the data side driver 20; 71 is a modulated voltage power supply section that generates voltage; 70 is a data side driver 20 for driving the EL display, a scanning side driver 30, a high voltage switching section 40, and a modulated voltage power supply section. 60 indicates a memory storing control data, 8° indicates a control section, and 90 indicates a discriminating section.

Further, HVV S'S' DATA "CLK" is an interface signal inputted to the control unit 80 from an external power, and indicates a horizontal synchronization signal, a vertical synchronization signal, a video data signal, and a video clock signal, respectively. Figure 2 is the first
Part A of the timing chart of the signal in the drive device shown in the figure is shown. Part A in Fig. 2 is a horizontal synchronization signal with a normal period, and part B is a horizontal synchronization signal with a shorter period than the normal period. Indicates when a signal is given.

As shown in FIG. 1, the discrimination section 90 is manually supplied with a horizontal synchronization signal and a reference signal generated from a clock or the like inside the control section 80 and kept at a LOW level for a predetermined period of time. Further, the LOI/level time of this reference signal is set from the sum of the pulse width of the voltage applied to the EL display and the time required to sufficiently discharge the charges charged in one line. As shown in FIG. 2, the reference signal reaches the 1110H level after maintaining the +OW level for a predetermined period of time, and in a normal section A, the horizontal synchronizing signal falls when the reference signal is at the HICI+level IO. At this time, the determination unit 9
If the stop signal is not output from 0 and the reference signal is not output, it detects the fall of the horizontal synchronization signal and returns to the LOW level, and is subsequently used to determine the length of the horizontal synchronization signal in the next cycle. It will be done.

On the other hand, in part B where the period of the horizontal synchronizing signal is short, the horizontal synchronizing signal falls when the reference signal is at the LOW level, and the determining section 90 detects this falling and outputs a stop signal.

This stop signal is input to the control unit 80, which receives the stop signal and controls the data side driver 20, the scanning side driver 30, the high voltage switching unit 40, the high voltage power supply unit 50, and the modulated voltage power supply unit 6.
0, and this signal stops the display drive of the EL display panel. Note that the determination unit 90
can be constructed using a latch, an AND gate, an inverter, etc. in J-.

(Effects of the Invention) As described above, according to the drive device of the present invention, when the period of the horizontal synchronization signal becomes short due to noise or equipment trouble, the display drive of the EL display panel is stopped. This can prevent damage to the drive device and improve safety.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of a drive device of the present invention. FIG. 2 is a diagram showing part of a timing chart of signals in the drive device obtained in the embodiment of the present invention.

Claims (1)

[Claims] (1) A driving device for an EL display panel having a double insulation structure in which a light-emitting layer is sandwiched between insulating layers, which includes a control section and a discrimination section, and the discrimination section receives a horizontal synchronization signal input from the outside. The control unit determines the length of the constant cycle reference signal issued from the control unit, and sends a stop signal to the control unit to stop the display drive of the drive device if the horizontal synchronization signal cycle is shorter than the reference signal cycle. A driving device characterized by sending.