JPS6319072B2 - - Google Patents

Description

Detailed Description of the Invention <Technical Field> The present invention reduces the influence of electrode resistance when aging thin-film EL panels in which the electrodes have a matrix structure by applying an AC voltage, and improves the aging of thin-film EL panels in which the electrodes have a matrix structure. This invention relates to an aging method that facilitates aging.

<Prior art> As shown in FIG. 5, a thin film EL panel with a double insulating film structure includes a group of band-shaped transparent electrodes 2 made of ITO or the like arranged in parallel on a glass substrate 1, and a layer of Si ₃ N ₄ etc. The dielectric material layer 3 is made of ZnS doped with an activator such as Mn.
An EL light-emitting layer 4 and a dielectric material layer 5 such as Si ₃ N ₄ are formed in this order by vacuum evaporation, sputtering, etc. to form a three-layer structure, and further on the dielectric material layer 5 are layers perpendicular to the transparent electrode 2. This structure is provided with a band-shaped back electrode group 6 extending in the direction shown in FIG.

In terms of an equivalent circuit, it is a capacitive element, and by applying a predetermined alternating voltage to a desired transparent electrode and a back electrode, a minute area sandwiched at the intersection of both electrodes emits light, producing characters, symbols, etc. It constitutes one picture element for displaying a pattern, etc.

Thin-film EL panels based on the above structure are manufactured by applying alternating current voltage to the transparent electrode group and the back electrode for a certain period of time after the thin film is fabricated, in order to stabilize changes in luminance over time and to remove defective elements due to initial failure. It is necessary to perform aging while applying power between groups.
At the time of aging, in order to simultaneously process the display pixels and to simplify the drive circuit, the electrodes drawn out in one direction are combined into one common electrode, as shown in Figure 6, and the electrodes drawn out in one direction are combined into one common electrode, and the electrodes drawn out in one direction are combined into one common electrode. The common electrodes are combined into one set of common electrodes. An alternating current voltage panel is applied to this set of common electrodes as shown in FIG. 6, and all intersection points are caused to emit light simultaneously to perform aging processing. The equivalent circuit of the EL panel in this case is shown in Figure 7. C is the capacitance of the light-emitting picture element, and R is the resistance of the transparent electrode.

When the display capacitance is small, the time constant C・R is small with respect to the applied pulse width, so a predetermined waveform is applied to every pixel. However, as the display capacitance becomes large, the time constant C・R is If it becomes larger than the width,
The waveform is no longer applied in the portion of the transparent electrode away from the terminal portion (FIG. 8). Since the pulse width cannot be made larger than necessary due to the relationship with other characteristics, a large display capacity panel has the problem that all picture elements cannot be aged uniformly.

<Purpose of the Invention> The present invention has been made in view of the above-mentioned problems, and is intended to reduce the influence of electrode resistance when aging a thin film EL panel having a large display capacity or one having a resistance electrode of 10Ω/□ or more. The present invention provides a method for uniformly aging the entire surface.

<Structure of the Invention> A method for aging a thin film EL panel according to the present invention comprises:
A thin-film EL panel consists of a matrix electrode consisting of two sets of strip-shaped electrodes made of a transparent conductive film such as ITO and an Al metal film, and an EL light-emitting layer placed on a substrate with a dielectric layer interposed between them. In the aging treatment method, all the electrode parts made of transparent conductive films such as ITO are short-circuited, and the same signal is applied.
The electrode portion made of the metal film such as Al is divided into a plurality of parts and short-circuited, and different signals are applied to each part.

<Example> Hereinafter, the present invention will be explained based on Examples.

First Example The first example is the back electrode side (low resistance electrode side).
A group of electrodes drawn out to one side (referred to as group X _A ),
To the electrode group (referred to as group X _B ) drawn out to the other side,
Apply phase-shifted waveforms. This reduces the number of picture elements that emit light at the same time by half, halving the current flowing through the transparent electrode, and reducing the influence of electrode resistance.

A drive connection diagram in this embodiment is shown in FIG. 1. All transparent electrodes yi are connected to a common electrode Y. Al is the electrode xi, the odd line is the common electrode x _A
, the even lines are connected to X _B.

When the pulses shown in Fig. 1 and 2 are applied to each of these common electrodes, the light emission timing of the picture elements on the odd-numbered lines of the Al electrode and the picture elements on the even-numbered lines are shifted, so the instantaneous current flowing through each transparent electrode yi is approximately halved. do.

An equivalent circuit resulting from this drive is shown in FIG.

Therefore, with this driving method, it is possible to perform aging processing with less influence of electrode resistance, even for panels with a display capacity that is double the number of lines on the Al electrode side than conventional panels.

Second Example The second example is the back electrode side (low resistance electrode side).
Waveforms of opposite polarity are applied to the electrode group drawn out to one side (X _A group) and the electrode group drawn out to the other side (X _B group). As a result, the picture elements between adjacent metal electrodes are simultaneously pulled to opposite polarities, so that almost no current flows through the transparent electrodes, and therefore there is almost no influence of resistance.

It is the same wiring diagram as the first embodiment, but the common electrode has a third
Apply the pulse shown in the figure.

According to this driving method, the light emission timing is simultaneous across the entire surface, but the polarity of the applied voltage is reversed between the picture elements on the odd-numbered lines and the picture elements on the even-numbered lines of the Al electrode.
The light emitting current flows on the Al electrode, but only partially flows on the transparent electrode, and the current at the terminal of the transparent electrode becomes almost zero.

An equivalent circuit resulting from this drive is shown in FIG. In the figure, r≈R/n (n: number of picture elements).

Therefore, with this driving method, the influence of the electrode resistance of the transparent electrode is almost eliminated, so there is no restriction on the display capacity during aging.

<Effects of the Invention> As is clear from the above explanation, according to the aging method of the present invention, processing with little or almost no drive distribution or waveform distortion due to the influence of electrode resistance can be achieved in aging of large display capacity panels. This improves aging efficiency. In the future, thin-film EL panels will aim for larger display capacities, and in that case they will be an effective aging method.

[Brief explanation of the drawing]

FIG. 1 is an electrode connection diagram of the aging method according to the present invention, FIG. 1 is a drive waveform diagram of the first embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of the first embodiment.
FIG. 3 is a drive waveform diagram of a second embodiment of the present invention, FIG. 4 is an equivalent circuit diagram of the second embodiment, and FIG. 5 is a structure of a thin film EL panel having a dot matrix electrode structure. FIG. 6 is a perspective view, FIG. 6 is an electrode connection diagram during conventional aging drive, FIG. 7 is an equivalent circuit diagram during conventional aging drive, and FIG. 8 is a diagram showing the rounding of the drive waveform on the transparent electrode. Explanation of symbols: 1: glass substrate, 2: front transparent electrode, 3: dielectric material layer, 4: EL light emitting layer, 5: dielectric material layer, 6: back metal electrode.

Claims (1)

[Claims] 1. A plurality of wires arranged in mutually orthogonal directions,
A thin film EL panel consisting of a matrix electrode consisting of two sets of strip-shaped electrodes made of a transparent conductive film such as ITO and a metal film such as Al, and an EL light emitting layer placed on a substrate with a dielectric layer interposed between them. In the aging treatment method, all the electrode parts made of the transparent conductive film such as ITO are short-circuited and the same signal is applied, and the electrode part made of the metal film such as Al is divided into multiple parts and short-circuited,
A method for aging thin-film EL panels characterized by applying different signals to each.