Optical heating apparatus

An optical heating apparatus comprising:

• a chamber that a workpiece is accommodated;
• an LED circuit board having a first main surface on which a plurality of light-emitting diodes (LEDs) that irradiate light onto the workpiece accommodated in the chamber are mounted;
• a first through hole that communicates between the first main surface and a second main surface of the LED circuit board, the second main surface being on a side opposite to the first main surface, the first through hole having a center located within 20% of a maximum diagonal distance of the first main surface from a center of gravity of the first main surface when viewed in a direction orthogonal to the first main surface of the LED circuit board;
• a heatsink provided on a side of the second main surface of the LED circuit board;
• a first fixing screw that is inserted through the first through hole of the LED circuit board and screwed into a screw hole, provided corresponding to the first through hole, to fix the LED circuit board and the heatsink;
• and
• a plurality of second fixing screws that are inserted through each of a plurality of second through holes of the LED circuit board and screwed into each of the plurality of second through holes, provided corresponding to each of the plurality of second through holes, to fix the LED circuit board and the heatsink,
• wherein on any concentric circle centered on the first fixing screw, there are two or fewer second fixing screws among the plurality of second fixing screws.