Temperature control system-based evaporation temperature control method for OLED (Organic Light Emitting Diode) organic layer

Abstract

The invention discloses a temperature control system-based evaporation temperature control method for an OLED (Organic Light Emitting Diode) organic layer. The evaporation temperature control method comprises a preheating process and an evaporation process, wherein the preheating process is divided into three temperature-rise processes with temperature gradients; the evaporation process comprises a step of controlling the temperature of an evaporation source by controlling the power of an evaporation power supply on the basis of an actually-measured deposition rate curve. According to the temperature control system-based evaporation temperature control method for the OLED organic layer, the stabilization time of the temperature of the evaporation source and the deposition rate is shortened, the use ratios of the organic materials of the evaporation source are improved, meanwhile, the degradation, the degeneration and the like of the organic materials caused when the temperature rise is too fast or the risen temperature is too high are avoided, and the production cost is lowered; by utilizing a characteristic that the evaporation rate is changed by 20-30% when the evaporation temperature is changed by 1%, the accuracy of the temperature control is improved, the stability of evaporation temperature is maintained, and the uniformity of evaporated films is improved.

Description

technical field [0001] The invention belongs to the technical field of organic electroluminescence display, and in particular relates to a method for controlling the evaporation temperature of an OLED organic layer based on a temperature control system. Background technique [0002] The OLED display device forms the carrier transport layer and the organic light emitting layer in the device by evaporating an organic light emitting material into a film. The preparation method of organic thin film layer, known has vacuum vapor deposition method, is divided into three basic processes: the deposition process of heating evaporation process, transportation process and substrate surface, wherein the main factor of heating evaporation stage is the material Saturation vapor pressure, saturated vapor pressure is related to temperature, it increases as temperature rises and decreases as temperature falls. According to the kinetic theory of gas molecules, the rate of change of depositio...

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Problems solved by technology

Nevertheless, the temperature control of OLED organic layer evaporation process still has the following problems: (1) organic materials are easy to decompose and denature at high temperature, and excessive temperature fluctuations in the heating sublimation process will lead to the danger of material denaturation; (2) evaporation temperature and deposition Too long rate stabilization time leads to low utilization of expensive organic materials and increased production costs; (3) The temperature accuracy is not controlled well, and the deposition rate is unstable, resulting in poor film uniformity and low doping ratio of guest materials are difficult to control, Affect device light emission

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