JPH0322877Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a current collecting band formed on a transparent electrode of an organic EL element or the like.

Conventional technology Organic EL panels, which are used for static displays such as characters and figures, and backlights for liquid crystal display panels, are made by sandwiching an organic EL element between transparent resin outer films in a sandwich-like manner and sealing it. Common. This organic EL panel
A typical EL element has a basic structure in which a reflective insulating layer, a light emitting layer, and a transparent electrode layer are laminated on a sheet-like back electrode.A specific example of the structure and manufacturing method is shown in Figure 3. This will be explained below with reference to FIGS.

The organic EL device 1 shown in FIGS. 3 and 4 consists of a first sheet A in which a reflective insulating layer 3 and a light emitting layer 4 are laminated on one side of a back electrode 2 made of Al foil, and a transparent insulating sheet 5 made of resin. A transparent electrode 6 of ITO is formed on one side of the
A second sheet B, in which a current collecting band 7 is formed by partially applying Ag paste to the periphery of the transparent electrode 6, is stacked and thermocompression bonded with the light emitting layer 4 and the transparent electrode 6 facing each other. When both sheets A and B are stacked, an external lead 8 is led out from a part of the current collecting band 7, and another external lead is led out from a part of the outer surface of the back electrode 2. 9 is derived. The reflective insulating layer 3 is made by dispersing powder of a highly reflective material (barium titanate, etc.) in a highly conductive organic material (cyanoethyl cellulose, etc.), and the light emitting layer 4 is made of the same organic material as described above. It is made by dispersing phosphor powder. In addition, the current collecting band 7
The current collecting band 7 is formed by dispersing Ag powder in a polymer paste adhesive, and the current collecting band 7 is formed for the following reason.

That is, the electrical resistance of the ITO transparent electrode 6 decreases as it becomes thicker, but on the other hand, as the thickness increases,
Since the transmittance of light generated in the light emitting layer 4 becomes worse,
It cannot be made too thick, and the electrical resistance is generally high. Therefore, if the power feeding point from the lead 8 of the transparent electrode 6 is limited to one point in a small area, the potential on the transparent electrode 6 when the EL element emits light is: The further away from the feeding point, the lower the intensity, and the greater the angle of inclination of the luminance distribution on the light emitting surface of the EL element. Therefore, by applying a low-resistance Ag paste along the periphery of the transparent electrode 6 to form a current collecting band 7, and expanding the power supply part from the lead 8 to the transparent electrode 6 from a point to a line, the transparent electrode 6 The potential distribution at the EL element is made more uniform, and the luminance distribution on the light emitting surface of the EL element is made more uniform.

Such an EL element 1, as shown in FIG.
Prepare a long first sheet A and a second sheet B in which a large number of EL elements are lined up in a row, and
Leads 8, 8... are temporarily fixed to current collecting bands 7, 7... formed at regular intervals with temporary fixing tape (not shown), and both sheets A and B are overlapped with their widths aligned. Heat and press through a laminator (not shown),
It is manufactured by cutting the integrated elongated EL element matrix 10 from the location indicated by the dashed line arrow in FIG.
Although not shown, the leads 9 are attached in advance to the back electrode 2 of the first sheet A with temporary tape or the like, or the leads 9 are attached after both the sheets A and B are cut. In addition, the cutting of each EL element of the above-mentioned integrated sheets A and B is carried out in the second
The current collecting band 7 is visually observed from above the sheet B, or detected by an optical sensor in an automatic machine, and the current collecting band 7 is
This is done by cutting with a cutter at a very small distance (approximately 2 mm).

Problems to be Solved by the Invention By the way, the current collecting band 7 visible through the transparent insulating sheet 5 and transparent electrode 6 of the second sheet B is silvery white, the color of Ag paste, and serves as the base of this current collecting band 7. At present, the light emitting layer 4 has a light color such as yellow-green, orange-yellow, or pink, and the color contrast between the light emitting layer 4 and the current collecting band 7 is poor. Therefore, when cutting the EL element base 10, which is made by overlapping and integrating the long first sheet A and the second sheet B, with the current collecting band 7 as a reference, the current collecting band 7 is visually inspected or cut by an optical sensor. It is difficult to clearly identify the current collecting band 7, and cutting errors often occur when cutting at a point that is too far away from or too close to the current collecting band 7, which reduces the yield of EL device manufacturing. It became one of the factors that made it worse. Furthermore, for each EL element 1 after cutting the EL element matrix 10,
The shape etc. of the current collecting band 7 are inspected visually or via an optical sensor, but inspection errors may occur from time to time due to the poor contrast between the current collecting band 7 and the light emitting layer 4. Ta.

Means for Solving the Problems The present invention has been made in view of the above problems, and solves the above problems with a current collecting band for transparent electrodes made of Ag paste colored in a dark color such as black. It was designed to do so.

Effect By making the current collecting band a dark color, when the underlying layer of the current collecting band is light colored such as a phosphor emitting layer, the contrast between the current collecting band and the underlying layer is improved, and the current collecting band Identification by visual inspection or optical sensor becomes easier and more accurate.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a plan view of an organic EL element 11,
Components that are the same as those in FIG. 3 are given the same reference numerals, and explanations thereof will be omitted. The only difference is the current collecting band 12 according to the present invention partially formed on the periphery of the transparent electrode 6 of the second sheet B', and this current collecting band 12 is dark colored.
For example, it is colored black.

Specifically, the current collecting band 12 is formed by applying Ag paste mixed with carbon powder, black dye, etc. onto the transparent electrode 6. In addition, when carbon powder is mixed into Ag paste to obtain black Ag paste, it is necessary to mix a large amount of carbon powder to obtain a sufficient black color. In the paste, a large proportion of Ag powder is separated from carbon powder, and as a result, the resistance value of the current collecting band 12 may increase. On the other hand, when a black dye is mixed into Ag paste, a sufficient amount of black Ag paste can be obtained with a small amount of black dye, and the resistance value of the current collecting band 12 can be reduced. It is preferable to form the current collecting band 12 with the following steps.

The EL element 11 having the black current collector band 12 is manufactured in the same manner as conventionally. That is, as in the conventional method, a long first sheet A and a second sheet B' are produced, and these two sheets A and B' are overlaid and integrated to form a long EL element as shown in FIG. Mother body 1
0' is obtained, and this is cut for each EL element using the current collecting band 12 as a reference. At the time of cutting, the current collecting band 12 is identified visually or optically. Since the current collecting band 12 is black, the contrast with the light-colored light emitting layer 4 of the base layer is clear, and the current collecting band 12 is visually or optically identified. Sensor identification can be easily and accurately performed, and therefore, cutting errors in the EL element matrix 10' are greatly reduced, making it possible to manufacture EL elements with a high yield.

Note that the color of the current collecting band is not limited to black, but may be any dark color that provides good contrast with the underlying layer.

Furthermore, the present invention is effectively applied not only to a current collecting band for a transparent electrode of an organic EL element, but also to a current collecting band formed on a transparent electrode of a touch panel installed in the front of a CRT display device.

Effects of the invention According to the invention, the current collection band of the transparent electrode can be easily and accurately identified visually or by an optical sensor, improving the manufacturing yield of organic EL panels, touch panels, etc. that have this type of current collection band. , especially organic EL
It is effective in manufacturing elements.

[Brief explanation of the drawing]

FIG. 1 is a plan view including a partially cut-out portion of an organic EL element having a current collecting band for a transparent electrode according to the present invention;
Figure 2 shows the EL in the manufacturing process of the EL element shown in Figure 1.
FIG. 3 is a partial plan view including a partially cut-out portion of the element matrix. Fig. 3 is a plan view including a partially cut-out portion of an organic EL element having a conventional current collecting band, Fig. 4 is an enlarged cross-sectional view taken along line X-X in Fig. 3, and Fig. 5 is of
FIG. 3 is a partial plan view including a partially cut-out portion of the EL element matrix in the manufacturing process of the EL element. 6... Transparent electrode, 12... Current collection band.

Claims (1)

[Scope of utility model registration request] 1. A current collecting band for a transparent electrode, the current collecting band being partially formed on the periphery of a sheet-like transparent electrode, the current collecting band being made of a darkly colored Ag paste.