| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable of forming a protective film with a relatively small thickness variation on an organic EL element.SOLUTION: A protective film forming method comprises the steps of: transferring a long belt-like base material 9 provided with a plurality of organic electroluminescent elements to a firm forming area in which an evaporation device 5 is arranged; and forming a protective film on a surface of an organic electroluminescent element by discharging a protective film forming material from the evaporation device 5. In the film forming area, a mask 6 with an opening 8 is arranged between the surface of the organic electroluminescent element and the evaporation device 5. The first opening end surface 81 of the mask has a continuous or gradual inclined surface 81a, and a second opening end surface 82 on the opposite side has a continuous or gradual inclined surface 82a. The inclined surface 81a of the first opening end surface and the inclined surface 82a of the second opening end surface incline so as to approach with each other toward the base material side. Each of inclination angles to the mask surfaces of the inclined surfaces is individually 10 to 40 degrees.SELECTED DRAWING: Figure 10 |
