JPS6093486A - Matrix type el display driving system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] A. Field of Industrial Application This invention is a matrix type EL for displaying characters, figures, etc.
(Electroluminescence) Used to drive display devices.

Problems to be Solved by the Prior Art and the Invention A common driving method for matrix type EL display devices is a line sequential driving method. In this method, selection is made by precharging the EL nacelle formed at the intersection of each electrode of the scanning side electrode group (hereinafter referred to as a scanning line) and each electrode of the data side electrode group (hereinafter referred to as a data line) arranged in a matrix. The method of emitting light,
There is a method of sequentially lowering the scanning lines to Ov and selectively applying a voltage required for light emission to the data lines according to this timing, but in all of these methods, the EL nacelle selective light emission is performed at a constant brightness. Therefore, matrix type EL display is CRT
Although it has the advantage of being thinner than a cathode ray tube (CRT), the lack of EL nacelle brightness modulation makes the display monotonous and its range of use is limited, making it difficult to put it to practical use as a display device to replace CRTs. .

In addition, as a brightness modulation means for the F and L cells of a matrix type EL display, actual brightness modulation is performed using a transformer for the EL nacelle light emitting time, and in a precharge type line sequential drive system, the EL nacelle is precharged. It has been proposed to perform brightness modulation by modulating the amount of discharged charges. However, this type of brightness modulation means is technically difficult and
It takes time for the L nacelle to emit light at high brightness, and a period of EL nacelle discharge drive is required, which deteriorates the frame frequency of the EL display drive, making it difficult to put it into practical use.

C1 Means for Solving the Problems The present invention aims at brightness modulation of an EL display that does not have the above problems, and the voltage required for light emission is sequentially applied to the scanning lines among the scanning lines and data lines arranged in a matrix. A line sequential driving method is provided in which a selected voltage in the range from Ov to a non-light emitting maximum voltage is applied to a data line selected according to the applied timing to cause an EL nacelle to selectively emit light. According to this method, BL selectively emits light by selecting the voltage applied to the data line.
The light emission brightness of the cell can be arbitrarily selected, making it easy to put the brightness modulation of an EL display into practical use.

2. Embodiment In the circuit shown in FIG. 1, A is a scanning side electrode group consisting of a plurality of scanning lines a1 to ai. B is a data side electrode group consisting of a plurality of data lines b1 to brX. The scanning lines a1 to a and the data lines b1 to bl''L are arranged in a matrix, and m x n EL cells cll to Ca are formed at each intersection. ssl to ss are connected to each scanning line a1 to a2. This switching element includes EL cells CIl~CM,
A D1-Dm to which the required light emission voltage VEL (approximately 200 V) is applied is a diode connected between each scanning line al to a, and one refreshing switching element SWI, and the switching element or is each scanning line a
1 to a2 are set to zero voltage and fresh voltage (approximately -140V)
Switch all at once to one of the following. SDI to SDn are push-pull type drive circuits connected to each data line b1 to b, for example, and outputting an output voltage according to an input voltage, each of which has one NPN type first transistor Trl and 11 PNP transistors. The second transistor Tr2 has a common base and its emitters are connected.
E (approximately 60V) is applied, and the second transistor Tr2,
The collectors of Tr2, - are grounded. E1 to En are input terminals Fl to Fn of each drive circuit 5t)1 to SDn.
This is a voltage variable drive control circuit that selects and outputs a voltage within the range of zero voltage to the maximum non-emission voltage.
This is an operational amplifier that selects and outputs a voltage within the range of .

Figure 2 shows the relationship between the applied voltage Vx and the luminance Bx of each EL nacelle ll to CI, □.Here, the applied voltage at the maximum luminance is 200V, and the applied voltage when the luminance reaches O is 200V.
Driving an EL display using the above circuit will be explained assuming that V-60V=140V.

First, the switching elements 5SI-8Sva are turned on sequentially from above to sequentially apply 200V to each scanning line a1 to ar. Now, 200V is applied to the topmost scanning line a1,
Considering the case where one EL cell cll is selectively caused to emit light, in this case, the input terminal F of the selected drive circuit SDI
Voltage V between θ and 30-odd V in operational amplifier El corresponding to 1
'x, and a voltage of 60V is applied to each of the other data lines b2-b. Then, one EL cell all emits light with a brightness B'x according to the applied voltage V'x (EL cells c12 to C of b)
, remains non-emitting.

EL cells cll to C+r in one scan uAa 1
When the selective light emitting operation of L is completed, the switching element SWI
to ground the scanning line al and connect each EL nacelle ll to c1. ．．
After discharging, 200V is applied to the next scanning line a2, and each EL nacelle 21 to C2 in the scanning line a2 is
Selective light emission of rw is performed. Thereafter, 200V is sequentially applied to each scanning line a3 to aa, and when all scanning is completed, the switching element 51111 is switched to -140■, and all scanning lines a1 to
Set aFv1- to -140V, and all data lines b1~
bl, all BL cells c11 to CK1 by applying 60V to
．． 200 V is applied and this is refreshed. During this refresh, the EL cell cllxc- that emitted light first emits light again with the same brightness.

The drive circuits 501 to SDn are operational amplifiers El.
If a variable output voltage in the range of 0 to 60 V is used for =En, this output can be directly input to the data lines b1 to bt''t-, so it is not necessarily necessary.

As described in detail, according to the present invention, EL nacelle brightness variation can be achieved simply by variable control of the input voltage of the data line, making it easy to put an EL display with a brightness modulation function into practical use. As a result, the scope of use of the EL display device as a thin display device replacing the CRT can be expanded. Furthermore, since the drive method does not perform precharging, high-speed drive with a large frame frequency is possible, and power consumption can be kept low.

[Brief explanation of the drawing]

FIG. 1 is a specific circuit diagram for implementing the driving method of the present invention, and FIG. 2 is a diagram showing the relationship between applied voltage and brightness in an EL nacelle of an EL display. A--Scanning side electrode group, a1 to a B--One scanning side electrode,
B--Data side electrode group, b l -b Vl----
Data side electrode, C11~C,,;-EL-fr/
L/, VEt, - required voltage for light emission.

Claims (1)

[Claims] (1) The required voltage for light emission is sequentially applied to the EL nacelle at the intersection of the scanning side electrode group and the data side electrode group arranged in a matrix, and to each electrode of the scanning side electrode group, and the data side electrode group is selected according to this timing. A matrix type EL display driving method characterized by selectively applying a voltage within a range from zero voltage to a maximum non-emission voltage to an electrode to selectively emit light with a brightness corresponding to the applied voltage.