For example, when the pressure regulator 1180 regulates the pressure inside the chamber 1110 to be the same as or similar to the atmospheric pressure, the gate valve 1110-1 may operate to open the chamber 1110. Thereafter, the pixel circuit substrate D may be charged into the chamber 1110. The pixel circuit substrate D may be charged into the chamber 1110 in various ways. For example, the pixel circuit substrate D may be charged into the chamber 1110 from outside the chamber 1110 by a robot arm or the like outside the chamber 1110. In another embodiment, when the first supporting portion 1120 is formed in a shuttle shape, the supporting portion 1120 with the pixel circuit substrate D thereon may be carried out of the chamber 1110 or into the chamber 1110 by a separate robot arm or the like outside the chamber 1110, and the first supporting portion 1120 is charged into the chamber 1110 from the outside of the chamber 1110.

The first mask assembly 100 may be arranged in the chamber 1110. In another embodiment, the first mask assembly 100 may be charged into the chamber 1110 from the outside of the chamber 1110 in the same manner as the pixel circuit substrate D.