Heating device for evaporation of OLED material

A heating device for evaporation of an organic light-emitting diode (OLED) material, comprising a crucible for receiving and containing therein an OLED material, the crucible comprising a body section and a top cover section connected to the body section, the top cover section having a top having a center in which a gas release hole is formed, and further comprising a lower heating coil that surrounds outside an outer circumference of the body section, an upper heating coil that surrounds outside an outer circumference of the top cover section, a lower thermally conductive temperature homogenizing sleeve arranged between the body section and the lower heating coil, an upper thermally conductive temperature homogenizing sleeve arranged between the top cover section and the upper heating coil, and a thermal insulation ring arranged between the upper and lower thermally conductive temperature homogenizing sleeves, the upper and lower heating coils being each connected to a power supply for individually controlling a heating temperature of each of the top cover section and the body section;

• wherein the lower thermally conductive temperature homogenizing sleeve is fixed to a platform;
• wherein the lower thermally conductive temperature homogenizing sleeve has a bottom on which a projection is formed and the platform comprises a recess formed therein to correspond to the projection so that the projection is receivable and retained in the recess, a thermal insulation pad being arranged between the projection and the recess so as to fix the lower thermally conductive temperature homogenizing sleeve to the platform;
• wherein the lower thermally conductive temperature homogenizing sleeve has a top in which a lower annular groove is formed and the upper thermally conductive temperature homogenizing sleeve has a bottom in which an upper annular groove is formed, the thermal insulation ring being fit in both the upper and lower annular grooves to separate the upper and lower thermally conductive temperature homogenizing sleeves from each other;
• wherein the lower thermally conductive temperature homogenizing sleeve has an inside diameter greater than an outside diameter of the body section of the crucible with a difference therebetween not greater than 10 mm;
• and the upper thermally conductive temperature homogenizing sleeve has an inside diameter greater than an outside diameter of the top cover section of the crucible with a difference therebetween not greater than 10 mm;
• wherein the upper thermally conductive temperature homogenizing sleeve has a height greater than a height of the top cover section of the crucible with a difference therebetween not greater than 10 mm;
• wherein the upper and lower heating coils have heating temperature ranges between room temperature and 1300° C. with control precision of temperature being less than 5° C.;
• wherein the upper and lower thermally conductive temperature homogenizing sleeves are made of a material of stainless steel;
• and
• wherein the thermal insulation ring is made of a material of ceramics and the thermal insulation pad is made of a material of ceramics.