JPH0660982A - Correction of defect in thin film electroluminescence panel - Google Patents

Abstract

PURPOSE:To correct XY bridges in a short time with high probability even if it is a thin film EL panel having large display capacity. CONSTITUTION:One ends of respective back plate groups formed by dividing a back plate 6A into N pieces are short-circuited by short-circuit patterns XA1,...XAN. One ends of respective back plate groups formed by dividing a back plate 6B into N pieces are short-circuited by short-circuit patterns XB1,...XBN. One ends of transparent electrodes 2 are short-circuited by short- circuit patterns Y, Y'. When XY bridges are corrected, voltage pulses are impressed between the short-circuit patterns XA1, XB1 and the short-circuit patterns Y, Y' ... between the short circuit patterns XAN, XBN and the short-circuit patterns Y, Y' while switching them in order to/from each other. In this way, display capacity of a thin film EL panel being driven is set always in I/N of the total display capacity, and the display capacity of the thin film EL panel being driven at one time is reduced, and a sufficient electric current is flowed to respective XY bridge places, so that the XY bridges can be corrected in a short time at a high correction rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect repairing method for a thin film electroluminescence (hereinafter abbreviated as EL) panel used for a display such as office automation equipment.

[0002]

2. Description of the Related Art A thin film EL panel having a double insulating film structure is shown in FIG.
It has a structure as shown in. That is, a large number of strip-shaped transparent electrodes 2 made of tin-doped indium oxide (hereinafter abbreviated as ITO) or the like are provided in parallel on the glass substrate 1. Further thereon, a first insulating film 3 made of a dielectric material such as Si ₃ N ₄ (silicon nitride), an EL light emitting layer 4 made of ZnS (zinc sulfide) doped with an activator such as Mn (manganese), Si The second insulating film 5 made of a dielectric material such as ₃ N _{4 is} sequentially formed by a vacuum vapor deposition method, a sputtering method or the like to have a three-layer structure. Further, a strip-shaped back electrode 6 made of a metal such as Al (aluminum) is formed on the dielectric material 5 in a direction orthogonal to the transparent electrode group 2.
Are provided in parallel.

The thin film EL panel having the double insulating film structure is a capacitive element in terms of an equivalent circuit, and by applying a predetermined alternating voltage to the desired transparent electrode 2 and the back electrode 6, both electrodes 2 are formed. The portion of the EL light emitting layer 4 having a small area sandwiched between the intersecting regions (picture elements) of 6 and 6 emits light to display characters, symbols or patterns.

In the thin film EL panel as described above, the transparent electrode 2 and the back electrode 6 are short-circuited within the picture element depending on manufacturing conditions.
(Hereinafter, referred to as XY bridge). this,
The causes of the XY bridge are as follows.

It is assumed that after the transparent electrode 2 is formed, foreign matter is attached to it, and then the first insulating film 3, the EL light emitting layer 4 and the second insulating film 5 are further formed thereon, and then the foreign matter is peeled off. . Then, there is nothing on the transparent electrode 2 at the location where the foreign matter has peeled off. And
If the back electrode 6 is formed on the back electrode 6, the transparent electrode 2 and the back electrode 6 where the foreign matter is peeled off are short-circuited.

A first insulating film 3, E is formed on the transparent electrode 2.
When the L light emitting layer 4 and the second insulating film 5 are formed, the first insulating film 3 is peeled off together with the films formed thereon due to insufficient adhesion between the transparent electrode 2 and the first insulating film 3. Then, when the back electrode 6 is further formed thereon, the transparent electrode 2 and the back electrode 6 where the respective films are peeled off are short-circuited.

A first insulating film 3, E is formed on the transparent electrode 2.
After the L light emitting layer 4 and the second insulating film 5 are formed, the first insulating film 3 is scraped off together with the films formed thereon by scratching the film surface due to a mishandling. Then, when the back electrode 6 is further formed on the back electrode 6, the transparent electrode 2 and the back electrode 6 where the respective films are scraped off are short-circuited.

Particularly, as the thin-film EL panel becomes larger (larger display capacity) and the area becomes wider, the number of defective portions also increases.

XY in the thin film EL panel as described above
In order to open the bridge portion, it is effective to raise the temperature of the short circuit portion. Then, as a method of raising the temperature of the XY bridge portion, there are a method of passing an electric current, a method of directly heating with a laser beam, and the like.

The following methods are available as methods for electrically correcting defects by passing a current through the XY bridge. (1) As shown in FIG. 3, the transparent electrode 2 and the back electrode 6 are all short-circuited. Then, by alternately and repeatedly applying a positive voltage pulse and a negative voltage pulse between the electrode Y having the transparent electrode 2 short-circuited and the electrode X having the back electrode 6 short-circuited, the EL light emitting layer 4 in all the picture elements. Light is emitted (see FIG. 5A for the applied waveform).

(2) As shown in FIG. 4, every other back electrode group 6 is selected and divided into a back electrode group 6A and a back electrode group 6B, and the back electrode group 6A and the back electrode group 6B are respectively combined. Short circuit. Moreover, all of the transparent electrode groups 2 are short-circuited. _A positive voltage pulse and a negative voltage are applied between the electrode X _A short-circuiting the back electrode group 6A and the electrode Y short-circuiting the transparent electrode group 2 and between the electrode X _B short-circuiting the back electrode group 6B and the electrode Y. And the voltage pulse of are repeatedly applied with a phase shift, and the EL light emitting layers 4 in the picture elements between the transparent electrode 2 and the back electrode 6A and between the transparent electrode 2 and the back electrode 6B are alternately made to emit light (applied waveform Refer to Fig. 5 (b)).

(3) The transparent electrode group 2 and the back electrode group 6 are short-circuited as shown in FIG. 4, as in the case of (2).
Then, after applying a positive voltage pulse between the electrode X _A and the electrode Y and between the electrode X _B and the electrode Y, the electrode is continuously adjusted so that the voltage of the electrode X _A with respect to the electrode X _B becomes positive. _A positive voltage pulse is applied between X _A and the electrode Y and between the electrode X _B and the electrode Y to cause the EL light emitting layer 4 in the pixel between the transparent electrode 2 and the back electrode 6A to emit light. Next, similarly, the pixel between the transparent electrode 2 and the back electrode 6B is made to emit light. Further, between the electrode X _A and the electrode Y and the electrode X _B
By applying a negative voltage pulse between the transparent electrode 2 and the electrode Y, a pixel between the transparent electrode 2 and the back electrode 6A and a pixel between the transparent electrode 2 and the back electrode 6B are obtained in the same manner as described above. Light up. Repeat the above operation continuously
(See Figure 5 (c) for applied waveforms).

(4) As in the case of (2), the transparent electrode group 2 and the back electrode group 6 are short-circuited as shown in FIG.
Then, after applying a voltage pulse to the electrode X _A so that the voltage of the electrode X _A with respect to the electrode X _B becomes positive, the voltages of the electrode X _A and the electrode X _B with respect to the electrode Y are inverted into positive and negative, and Electrode X _A and electrode Y are arranged so that EL light emitting layer 4 does not emit light.
And a voltage pulse is applied between the electrodes X _B and Y (first frame). Next, after applying a voltage pulse to the electrode X _B so that the voltage of the electrode X _B with respect to the electrode X _A becomes positive, the voltages of the electrode X _A and the electrode X _B with respect to the electrode Y are inverted to negative and positive. Moreover, voltage pulses are applied between the electrodes X _A and Y and between the electrodes X _B and Y so that the EL light emitting layer 4 does not emit light (second frame). Thereafter, the first frame and the second frame are alternately repeated.
(See Figure 5 (d) for applied waveforms).

[0014]

However, the above conventional XY bridge correction method has the following problems. In the method (4) in the method of electrically correcting a defect by passing a current through the XY bridge portions of (1) to (4), the electrode X _A and the electrode X _A are also formed after the EL light emitting layer 4 of the pixel is made to emit light. Since positive and negative voltage pulses are applied to X _B to such an extent that the EL light emitting layer 4 does not emit light, current always flows through the transparent electrode 2 having the XY bridge to heat the vicinity of the XY bridge. Therefore, the method of (4) is (1)
The short-circuited portion can be corrected with a higher probability than the methods (3) to (3).

However, in the case of a large-sized large-capacity thin-film EL panel, it is difficult to pass a sufficient current through the short-circuit portion due to the large display capacity, and the correction rate becomes low. In addition, if an infinitely large current is applied when the XY bridge is corrected, normal picture elements will also be destroyed.

On the other hand, in the case of the method of directly heating the XY bridge portion by the laser beam to open the XY bridge, the short-circuited portion can be corrected with high probability. However,
There is a problem that it is difficult to adopt as an XY bridge correction method for a thin film EL panel because it takes a long working time and the cost of the laser device is high.

Therefore, an object of the present invention is to provide a defect repairing method for a thin film EL panel capable of repairing an XY bridge in a short time with a high probability even in a thin film EL panel having a large display capacity.

[0018]

To achieve the above object, according to the present invention, each of a plurality of parallel transparent electrodes forming a thin film EL panel is arranged in parallel to the transparent electrodes at right angles. When a short circuit occurs between the transparent electrode and the back electrode in any of the picture elements formed in the intersecting region of each of the back electrodes, a voltage is applied between the shorted transparent electrode and the back electrode. In the defect correction method for a thin film EL panel in which both the short-circuited electrodes are opened, at least one of the transparent electrode group or the back electrode group is divided into a plurality of blocks, and a voltage is applied between the short-circuited transparent electrode and the back electrode. When a voltage is applied between the transparent electrode group and the back electrode group for applying, in the case of applying a voltage to the divided transparent electrode group or the back electrode group, each of the divided block units It is characterized by sequentially applying.

[0019]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. As described above, the XY bridge portion in the thin film EL panel has a slight resistance due to the oxidation of the metal surface or the residual foreign matter. Therefore, if a sufficient current is passed between the transparent electrode and the back electrode at the XY bridge, heat is generated, and this portion opens and can be corrected.

However, when the thin film EL panel becomes large and the display capacity becomes large, even if a voltage pulse is applied between the transparent electrode and the back electrode, the current flowing to the XY bridge portion is limited because of the large display capacity. I am not able to pass enough current.

Therefore, in the present invention, the area of the thin film EL panel driven at the time of XY bridge correction is adjusted to
Sufficient current is allowed to flow in an appropriate range at the XY bridge.

FIG. 1 is an explanatory diagram of electrode short circuit in the defect correcting method of the thin film EL panel of this embodiment. The thin film EL panel in this embodiment has the same structure as the thin film EL panel shown in FIG. Therefore, the following description is based on FIG.
The explanation will be given using the numbers of the respective parts in.

In this embodiment, the XY bridge correction is carried out as follows. At the time of manufacturing the thin film EL panel, the back electrodes 6 formed by alternately projecting outwardly from opposite sides of the first and second insulating films 3 and 5 are divided into an arbitrary number "N". The rear electrodes 6A protruding from one side of the first and second insulating films 3 and 5 are divided into N rear electrode groups, and the protruding ends of the respective rear electrode groups are short-circuited patterns XA ₁ and XA. _2, ..., to short-circuit in the XA _N. Similarly, the projecting end of each back electrode group formed by dividing the back electrode 6B projecting from the other side of the first and second insulating films 3 and 5 into N back electrode groups is short-circuited with a short pattern XB. _1, XB _2, ..., to short-circuit in the XB _N.

Also, when manufacturing the thin film EL panel,
The transparent electrode 2 formed so as to project from one of the opposite sides of the insulating films 3 and 5 is short-circuited by the short-circuit pattern Y.
Further, the transparent electrode 2 formed so as to project from the other side of the first and second insulating films 3 and 5 is short-circuited by the short-circuit pattern Y ′.

In other words, in the present embodiment, the back electrode 6A or the back electrode 6B is not short-circuited by a single short-circuit pattern, but is divided into an arbitrary number and short-circuited to correct the XY bridge. Thin film E driven to
The capacity of the L panel is adjusted.

When the voltage pulse is applied to the back electrode 6A and the back electrode 6B, which are short-circuited by dividing into an arbitrary number "N" as described above, for example, the following is performed. That is, the short-circuit pattern XA ₁ , XB ₁ → short-circuit pattern X
A _2, XB ₂ → ... → short pattern XA _N, a switch for switching the applying path of the voltage pulses in the order of XB _N. Then, by sequentially switching this switch, the voltage pulse is changed into the short-circuit patterns XA ₁ and XB ₁ and the short-circuit pattern Y,
Y 'between the → short-circuit pattern XA _2, XB ₂ and the short-circuit pattern Y, Y' between the → ... → short-circuit pattern XA _N, XB _N and the short-circuit pattern Y, sequentially switching between the Y '.

In this way, by driving the thin film EL panel and correcting the XY bridge, the capacity of the driven thin film EL panel is always 1 / of the total display capacity.
It can be N. As a result, even a large-sized thin film EL panel having a large display capacity has a small display capacity driven at one time, and a sufficient current can be supplied to each XY bridge portion. Therefore, the XY bridge can be corrected in a short time at a high correction rate.

In the above embodiment, as described above, since the short circuit pattern is used when short-circuiting the back electrodes 6A and 6B, workability and certainty at the time of connection with the current-carrying jig can be improved. it can. That is, when the short-circuit pattern is not used, it is necessary to provide an energizing jig capable of accurately aligning each back electrode 6 at the same time. It happens.

In the above embodiment, the back electrode 6 is divided into an arbitrary number, but the transparent electrode 2 may be divided. Furthermore, by dividing both the back electrode 6 and the transparent electrode 2, the capacitance of the thin film EL panel can be adjusted more finely, and the correction rate of XY bridge correction can be dramatically increased.

[0030]

As is apparent from the above, according to the defect repairing method for a thin film EL panel of the present invention, at least one of the transparent electrode group or the back electrode group is divided into a plurality of blocks,
In applying a voltage between the transparent electrode group and the back electrode group to apply a voltage between the transparent electrode and the back electrode short-circuited in the picture element, the divided transparent electrode group or back electrode group When a voltage is applied to, the voltage is applied to each of the divided blocks sequentially,
When the XY bridge is corrected, the thin film EL panel is driven in the block unit.

In this way, even in a thin-film EL panel having a large display capacity, it is possible to reduce the display capacity driven at one time and allow a sufficient current to flow through the XY bridge.
Therefore, according to the present invention, a thin film EL having a large display capacity is provided.
Even with a panel, the XY bridge can be corrected with a high probability in a short time.

[Brief description of drawings]

FIG. 1 is an explanatory view of an electrode short circuit in a defect repairing method for a thin film EL panel according to the present invention.

FIG. 2 is a partially cutaway perspective view of a thin film EL panel.

FIG. 3 is an explanatory diagram of electrode short circuit in a conventional example.

FIG. 4 is an explanatory diagram of electrode short-circuiting in the conventional example, which is different from FIG.

FIG. 5 is a diagram showing an example of a voltage pulse waveform applied to the electrodes short-circuited as shown in FIGS. 4 and 5.

[Explanation of symbols]

1 ... Glass substrate, 2 ... Transparent electrode, 3
... 1st insulating film, 4 ... EL light emitting layer, 5
... second insulating layer, 6, 6A, 6B ... back _{electrode, XA 1 ~XA N, XB 1} ~XB N, Y, Y '... short pattern.

Claims (1)

[Claims] 1. A thin film electroluminescence panel is formed in an intersection region between each of a plurality of transparent electrodes arranged in parallel and each of a plurality of back electrodes arranged in parallel to and orthogonal to the transparent electrodes. When the transparent electrode and the back electrode are short-circuited in any of the selected picture elements, a voltage is applied between the short-circuited transparent electrode and the back electrode to open both the short-circuited electrodes. luminescence·
In a panel defect repairing method, at least one of a transparent electrode group or a back electrode group is divided into a plurality of blocks, and the transparent electrode group and the back electrode are arranged to apply a voltage between the short-circuited transparent electrode and the back electrode. When a voltage is applied to the divided transparent electrode group or the back electrode group when a voltage is applied to the group, the thin film electroluminescence is characterized in that the voltage is sequentially applied to each of the divided block units. -Panel defect repair method.