JPS60244992A - Aging of display panel - 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 Technical Field of the Invention The present invention relates to a method for aging display panels such as EL (electronic luminescence) panels, and more particularly to an aging method that can uniformly age large EL panels.

Background of the Technology EL panels are of the matrix type having capacitive display cells and electrodes having a resistive component. In this type of display panel, before it is assembled into a unit and manufactured into a product, a so-called aging process is performed to apply a sliding voltage over the entire surface of the panel for about 100 to 200 hours to emit light in order to stabilize its characteristics.

Prior Art and Problems When performing this aging, conventionally, driving voltage pulses were applied to the entire surface of the EL panel at the same time.

However, with this method, as the EL panel becomes larger, the EL
Due to the transparent electrode resistance value R of the panel and the panel cell placement C, the cell voltage waveform becomes duller as the distance from the driver increases, and a uniform voltage value is not applied to the entire panel. As a result, the cell voltage of cells far from the driver becomes lower than that of cells close to the driver, resulting in uniform aging ′tJ.
1 will no longer be held. This becomes more noticeable as the panel becomes larger. Next, this will be explained in detail with reference to FIGS. 1 to 4.

In Figure 1 (2), 1 is an EL panel, 2 is an X-side driver, and 3 is a Y-side driver. 4 is an X-side transparent electrode formed on the EL panel 1 (actually (2 is a plurality of (It has a matrix shape with the Y-side metal electrode, which will be described later.)
Similarly, 5 is the Y-side metal electrode furthest from the X-side driver 2 formed on the KL panel 1. The transparent electrode 4 has a resistance value R.

The metal electrode 5 has a resistance value of zero. In the conventional method described above, from the X side driver 2 to all the X side transparent electrodes.

Since aging is performed by applying driving pulses having the waveform shown in FIG. 2 to all the Y-side metal electrodes from the Y-side driver 5, the RC of the entire surface of the panel becomes a load.

As a result, as the area of the panel increases, this RC time constant increases, and at the farthest point cell seen from the X side driver 6,
The roundness of the cell voltage waveform shown in FIG. 6 1 becomes larger as shown by the dotted line. Therefore, uniform aging cannot be achieved over the entire surface of the panel. Note that if aging is performed with a waveform having a wide pulse width, there will be a large destruction mark when the EL cell is destroyed, so it is desirable to perform aging with a pulse having a narrow width. FIG. 4 (α) shows the equivalent circuit for one line seen from the X-side driver, and FIG. 4 (bl shows the equivalent circuit seen from the Y-side driver for one line furthest from the X-side driver. The relationship R=nr holds between the values r and R. The above-described rounding of the cell voltage waveform is clearly seen in this figure.

OBJECTS OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and it is an object of the present invention to provide an aging method that can uniformly age a large EL panel.

Structure of the Invention In the present invention, the display screen is divided into a plurality of regions by dividing the electrode group of the display panel in the same direction into a plurality of groups, and alternating driving voltage pulses are applied to each region in a time-sharing manner. The above objective is achieved by performing aging while preventing the application of drive voltage pulses to non-selected areas of the respective areas.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to FIGS. 5 to 9.

The present invention does not apply driving voltage pulses to the entire display panel at the same time, but divides the display panel into multiple regions and carefully combines the voltage waveforms in each region. This makes it possible to reduce the rounding of the voltage waveform caused by aging, and to achieve uniform aging over the entire panel. Next, the details of the embodiment will be fully explained.

FIG. 5 shows the aging circuit configuration. In this example, the electrodes in the Y direction are divided into 4 groups (generally multiple groups); the display screen 11 is divided into 4 areas (as indicated by dotted lines).
It is divided into two parts. 12 is the X side driver, 13+, 13
2 + 13s, 134 is the Y side driver of each area, R
1-R4, C, to C4 are the resistance value and capacitance value for one line in each region. During aging, as shown in the waveform diagram in Figure 6, a driving voltage pulse (indicated by Alternating drive voltage pulses are time-divisionally applied to each region (Y, ,
Y, , Y, , Y.

), in this case, for example, X-Y.

When selecting, the unselected area (X-Y2), (X-Ys
), (X - Y4) are no-load as seen from the X-side driver (substantially no driving voltage pulse is applied). A single shaded pulse is applied as shown. Similarly, a cancel pulse is applied to the non-selected area so that the area becomes unloaded when viewed from the X-side driver. FIG. 7 shows the cell voltage waveform when driving voltage pulses are applied to each region in this manner. The effect of the cancel pulse is clear from this figure.

Next, the RC time constants when aging is performed using the method of the present invention and when aging is performed using the conventional method will be compared.

In the case of the method of the present invention, the equivalent circuit of the X-Yl cell seen from the X side driver is as shown in Figure 8 (α) → Figure 9 (α). The equivalent circuit is as shown in FIGS. 8(b) to 9(b). The RC time constant τ in this case is TP1R,C.

becomes.

Similarly, the Rc time constant "2"(A't 182
) ・RC time constant of C2X-Y3 τps=(R, +R
q+Rs) -C3X-Y4 (1) RC time constant TP,
=(R, +R, +R, +R4> -C4.

10,000, the RC time constant τP in the conventional method is τp=(R1+
You+R3+R, )・(C, +C, +C, -+-C,).

・°・τPI, τ't +τ'3 +τp, <TP In this way, in the case of the present invention, the time constant seen from the driver is smaller than in the conventional case, so it is possible to reduce the rounding of the cell voltage waveform. This allows for more uniform aging.

Effects of the Invention As described above, according to the present invention, it is possible to uniformly age a large EL panel.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of conventional aging procedures, Figure 2 is a drive voltage pulse waveform diagram of the same driver, Figure 6 is a cell voltage waveform diagram of the same, and Figure 4 (α) and (A) are drivers of the same side. 5 to 9 show an example of the aging method for a display panel according to the present invention, and FIG. 5 is an aging circuit configuration diagram, and FIG. is a drive voltage pulse waveform diagram, Figure 7 is a cell voltage waveform diagram, and Figure 8 is a diagram of a cell voltage waveform.
Figure (LL), (b) and 's9 figure (α) l (j
) is an equivalent circuit diagram of an X-Y cell viewed from each side driver. In the figure, 11 is the display screen, 12 is the X side driver, 16I,
13z t 13g + 134 is a Y-side driver for each divided area. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] In an aging method for a matrix display panel consisting of capacitive display cells and electrodes having a resistive component, electrodes in the same direction are divided into multiple groups, the display screen is divided into multiple regions, and each Area C: Aging of a display panel characterized by applying alternating drive voltage pulses in a time-division manner, and performing aging in a manner such that driving voltage pulses are not applied to non-selected areas of each area. Method.