JPH0481316B2 - - Google Patents

Description

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

[Conventional technology]

In general, thin film EL elements are formed by sputtering with the lead-out part of the front electrode 2 formed on the insulating substrate 1 hidden by the substrate holder 3, as shown in FIG. , thin film 4 such as an insulating layer or a light emitting layer by vapor deposition etc.
are successively formed, and the front electrode 2 is drawn out from the portion exposed from the thin film 4 to the end of the insulating substrate 1, as shown in FIG. In the figure, 5 is a second insulating layer, 6 is a light emitting layer, 7 is a first insulating layer, 8 is a back electrode, 9 is a bonding wire, 10 is an evaporation source, and 2A is a front electrode extension part (for example, JP-A-59-27497 (Figure 1), JP-A-59-5594
(Figures 2 and 4), Japanese Unexamined Patent Publication No. 1983-91595, etc.).

[Problem that the invention seeks to solve]

However, when attempting to increase the area by connecting multiple XY matrix type chip-shaped EL elements 11 formed in this way as shown in FIG. It is difficult to connect the chips of an XY matrix EL element, where the line spacing is, for example, several mm or less, in such a way that the pitch between the electrodes is maintained equal to other chips even when connecting the chips. .

[Means for solving problems]

In order to solve these problems, the present invention connects the front electrodes of the EL elements to each other between extraction electrodes that are formed on the same surface as the back electrode and connected to the front electrode via a through hole. It is something that

[Effect]

There is no need to provide a connecting portion between the front electrodes at each element end.

〔Example〕

FIG. 1a is a sectional view showing one embodiment of the present invention, and FIG. 1b is a plan view thereof (FIG. 1a is a sectional view taken along the line a-a in FIG. 1b).

Next, the manufacturing method will be explained using FIGS. 2 and 3. First, in the same process as before, a striped transparent front electrode 2 made of ITO, SnO ₂ , etc., and Al ₂
First insulating layer 5 made of O ₃ , Si ₃ N ₄ , etc., ZnS:
A light emitting layer 6 made of Mn, ZnS:TbF ₂ or the like and a second insulating layer 7 made of the same material as the first insulating layer are sequentially formed using a film forming technique such as electron beam (EB) evaporation or sputtering. .

Next, conventionally, a back electrode is formed, but in this embodiment, prior to that, a through hole 12 is formed on the front electrode 2 at the end of the chip, except for the light emitting dots, using a dry etching method. form (Figure 2). In this case, a hole reaching the interface between the front electrode 2 and the first insulating layer 5 can be formed by using a reactive ion etching method, a sputter etching method, or a combination of both.

Next, a thin Al film for electrodes is formed on the entire surface including the inside of the through-hole 12 by a sputtering method, and a bonding pad 13 for leading out the front electrode is formed on the back electrode 8 perpendicular to the front electrode 2 and on the through-hole 12 by photolithography. are formed simultaneously. The intersection between the front electrode 2 and the back electrode 8 (the shaded area in FIG. 1b) becomes a light emitting dot.
Finally, the end of this chip-shaped thin film EL element is arranged so that the distance d from the center of the end electrode is less than 1/2 of the electrode pitch P on the chip, as shown by the broken line in Figure 2. Cut along the plane (Figure 3).

With this structure, the front electrode 2
By using the bonding pad 13, the electrode can be drawn out on the same surface as the back electrode 8, and the electrode exposed part (drawing part) at the card edge part, which was necessary in the past, is no longer necessary. By preparing a wide area in advance for forming a thin film such as, and later cutting it to a predetermined size,
An EL element with uniform characteristics up to the edges can be obtained.
In other words, when forming a thin film using the method described above, the film inevitably becomes thinner at the edges.
There is a problem that the electric field strength applied to the light emitting layer becomes non-uniform, resulting in uneven brightness and pixel defects due to dielectric breakdown. Uniform characteristics can be obtained. Also, as mentioned above, d
By setting ≦P, the chips can be arranged and connected to each other so that the spacing between the electrodes is equal to the electrode pitch on the chip even when the chips are connected to each other.

Next, such a chip-shaped EL element 21 is
A large number of light emitting dots are arranged and fixed in rows and columns on a common transparent substrate 22, and the electrodes are connected to each other by bonding wires 9. However, in this case, if wire bonding is performed on the light emitting dots, the electrodes may be damaged due to bonding mistakes, etc. Since this may lead to the occurrence of chipping, all connections are made at areas other than the light emitting dots, that is, at non-intersecting areas between the front electrode 2 and the back electrode 8. In addition, since the area of the above-mentioned non-intersecting portion of the edge portion is less than 1/2 of the area other than the edge portion, the connection is generally made while avoiding the edge portion, but as shown in Figure 1b, When interconnecting four chips around point A, in order to avoid the vertical bonding wires and the horizontal bonding wires from crossing and contacting each other, connect only one direction at the center. Make the connection at the edge. This corresponds to the connection by the bonding wire 9A in FIG.

Although an example using a thin film EL element having a structure in which the light emitting layer is sandwiched between the first and second insulating layers has been described above, the present invention is not limited to this. It can be applied to all cases using an EL element with a structure in which an electrode and a back electrode are crossed.

〔Effect of the invention〕

As explained above, according to the present invention, the front electrodes of the EL elements are connected to each other between the extraction electrodes formed on the same surface as the back electrodes and connected to the front electrodes through the through holes. By doing this, the electrode spacing between the EL elements can be
It is now possible to arrange and connect the electrodes so that they are equal to the electrode pitch on the EL element, and it is also possible to cut off the ends of each element and use only the uniform part.
It becomes possible to realize a large-area, high-resolution XY matrix EL display panel using the piecing method.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, FIG. 1a is a sectional view thereof, FIG. 1b is a plan view, FIGS. 2 and 3 are sectional views in the middle of manufacturing, and FIG. 4 6 to 6 are cross-sectional views showing conventional examples. DESCRIPTION OF SYMBOLS 1... Insulating substrate, 2... Front electrode, 6... Light emitting layer, 8... Back electrode, 9... Bonding wire, 12... Through hole, 13... Bonding pad for leading out front electrode, 21... EL element,
22...Transparent substrate.

Claims (1)

[Claims] 1. A front electrode formed on a transparent insulating substrate;
A plurality of EL elements each having a back electrode facing a front electrode through an EL light emitting layer are arranged on the same transparent substrate with the front electrode side facing the transparent substrate, and a wire is connected between the corresponding electrodes of the EL elements. In an EL display panel that is connected by bonding, the front electrodes between the EL elements are connected between the extraction electrodes formed on the same surface as the back electrode and connected to the front electrode via a through hole, and the back electrode An EL display panel characterized in that mutual connections are made between parts of the back electrode that do not intersect with the front electrode. 2. The EL display according to claim 1, characterized in that the bonding wires connecting between the front electrodes and the bonding wires connecting between the back electrodes are arranged so as not to intersect with each other three-dimensionally. panel.