Production method for optical upconversion organic film, optical upconversion organic film production device, and optical upconversion organic film

A production method of an optical upconversion organic film, the method comprising:

• holding a powder precursor containing a triplet sensitizer and an organic luminescent material in a holding space of a precursor holder, the holding space having a predetermined height;
• applying pressure to the powder precursor along a height direction of the holding space;
• and
• performing temperature control, in which given that a direction orthogonal to the height direction is defined as an axial direction, a heating member having a temperature gradient from a high temperature range to a low temperature range along the axial direction is moved in the axial direction relative to the precursor holder, the high temperature range being at or above a melting point of the organic luminescent material, the low temperature range being below a coagulation point of the organic luminescent material.

An optical upconversion organic film producing apparatus configured to produce an optical upconversion organic film, the apparatus comprising:

• a precursor holder having a holding space with a predetermined height, and configured to hold a powder precursor containing a triplet sensitizer and an organic luminescent material in the holding space;
• a pair of clamping sections configured to clamp the precursor holder in a height direction;
• a press section configured to apply pressure so that at least one of the pair of clamping sections is pressed toward the other of the pair of clamping sections;
• and
• a first heating mechanism configured to raise a first temperature of the powder precursor and a second temperature of the powder precursor by heating to be different temperatures from each other to generate a temperature gradient along an axial direction, given that a direction orthogonal to the height direction is defined as the axial direction, an end of the powder precursor close to one side of the axial direction is defined as a first end, an end of the powder precursor close to the other side of the axial direction is defined as a second end, a temperature of the first end is defined as the first temperature, and a temperature of the second end is defined as the second temperature, wherein
• the first heating mechanism is configured to raise the first temperature and the second temperature by heating to or above a melting point of the organic luminescent material, and then to gradually lower the first temperature and the second temperature to below a coagulation point of the organic luminescent material while maintaining a temperature difference between the first temperature and the second temperature.

An optical upconversion organic film producing apparatus configured to produce an optical upconversion organic film, the apparatus comprising:

• a precursor holder having a holding space with a predetermined height, and configured to hold a powder precursor containing a triplet sensitizer and an organic luminescent material in the holding space;
• a pair of guide sections being members configured to sandwich the precursor holder by pressing the precursor holder in a height direction, the pair of guide sections being configured to guide the precursor holder so that the precursor holder is relatively movable along an axial direction, given that a direction orthogonal to the height direction is defined as the axial direction;
• a second heating mechanism configured to heat the pair of guide sections to generate a temperature gradient from a high temperature range to a low temperature range along the axial direction, the high temperature range being at or above a melting point of the organic luminescent material, the low temperature range being below a coagulation point of the organic luminescent material;
• and
• a moving mechanism configured to move the precursor holder in the axial direction relative to the pair of guide sections.

An optical upconversion organic film, comprising:

• a triplet sensitizer;
• and
• an organic luminescent material, wherein
• the organic luminescent material has ultraviolet luminescence, and
• the optical upconversion organic film is a film having crystallinity.