an organic light emitting diode

Abstract

The application discloses an organic light-emitting diode with a non-pixelated anti-short circuit design structure, including a light-emitting layer, an electron transport layer and a hole transport layer respectively located on both sides of the light-emitting layer; A composite electrode structure is provided on one side of the layer, or a single electrode / composite electrode structure or a composite electrode structure / single electrode is provided on the side of the electron transport layer and the hole transport layer away from the light-emitting layer; The electrode structure sequentially includes a single electrode, a semiconductor material layer and an extended high conductivity layer from outside to inside; the single electrode is the first electrode or the second electrode. The extended high-conductivity layer in the design scheme of this application will fail after a short circuit, and a reverse bias structure will appear to block the passage of the short-circuit failure current and achieve the purpose of short-circuit protection, thus improving the reliability of the screen and improving the organic light emission. lifetime of the diode.

Description

technical field [0001] The present disclosure generally relates to the field of lighting devices, and in particular designs an organic light-emitting diode without short-circuit protection of a metal grid. Background technique [0002] In the manufacturing process of organic light-emitting diode (OLED) screens, there are inevitably defects such as dust particles, burrs, pinholes, cracks, etc., and the distance between the anode and the cathode of the OLED screen is usually very small (about tens to hundreds nano). Therefore, in this state, the anode and cathode may be in direct contact causing defects (called short-circuit points), or the organic layer between the anode and cathode may become thinner than other locations. When the OLED device is operating, the current tends to pass through such defect points rather than from other locations. This causes heat to accumulate at such defect points. This leads to damage to the quality and reliability of the entire OLED device....

AI Technical Summary

Problems solved by technology

[0007] When a defect occurs, this anti-short-circuit resistance can avoid the occurrence of a short-circuit (because the resistor is connected in series with the short-circuited device), so there are two important factors that must be considered in this type of anti-short-circuit system, (1) the pixels of the screen ( That is, n in the above formula cell ) should be enough; (2) anti-short circuit resistance (that is, R in the above formula cell-spl ) should be as large as possible; if the above two necessary conditions cannot be met, the anti-short-circuit effect will not be obvious, and high heat will be generated at the short-circuit point due to high current (P=I 2 R; P=power, I=current, R=resistance), and then reduce its reliability; the experiment shows that the above-mentioned anti-short circuit system is suitable for the power supply of "constant voltage", that is, the current can have a large range of changes, but most The power supply device cannot be reached, and the OLED lighting screen body is mainly based on a "constant current" power supply. The above-mentioned short-circuit protection mechanism causes a large amount of failure current due to the short-circuit point (that is, the current passing through the short-circuit point (effectively supplying the normal OLED device current) + failure current at the short circuit point = total output current of the constant power supply)) resulting in a decline in the photoelectric performance of the screen

Among them, the resistance of the loop protection device is large enough to match the equivalent resistance of the light-emitting pixels, and the circuit protection design in the form of series resistance can be achieved, but the value of the equivalent resistance of the light-emitting pixels is usually tens of thousands to hundreds of thousands of ohms after calculation. Level, the resistance of the circuit protection device is usually far less than this order of magnitude, so a high proportion of short-circuit current will pass through the short-circuit point, causing the overall light efficiency of the screen to change accordingly

[0008] Due to the large effective light-emitting area of ​​the lighting screen, in order to avoid the failure of the overall screen due to a small short-circuit defect, "pixelation" has become a common method, such as the many solutions mentioned above; pixelated OLED screen It shows a significant short-circuit protection effect, but at the same time pixelation causes many performance losses, such as: (1) The proportion of effective light-emitting area decreases, resulting in a higher brightness within a limited light-emitting area to achieve the expected level, which will affect OLED. Screen life; (2) After long-term use of the OLED screen, the local light-emitting area of ​​the light-emitting edge may shrink. Let’s say that a screen with an area of ​​100*100 is cut into 100 pixels of 10*10, and its side length ratio is estimated to be about 40*100 / 400=40 times), this phenomenon will also cause a significant shortening of the service life of the OLED screen

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