Abstract: Disclosed are polycyclic aromatic compounds that can be employed in various organic layers of organic electroluminescent devices. Also disclosed are organic electroluminescent devices including the polycyclic aromatic compounds. The organic electroluminescent devices are highly efficient and long lasting and have greatly improved luminous efficiency.

Abstract: An optical imaging system includes a plurality of lenses disposed along an optical axis from an object side of the optical imaging system toward an imaging plane of the optical imaging system. The lenses are separated from each other by respective air gaps along the optical axis between the lenses. The lenses include a first lens closest to the object side of the optical imaging system. The conditional expressions 1.5 mm<Gmax, TL<12.0 mm, and 0.15<R1/f are satisfied, where Gmax is a maximum air gap along the optical axis among all of the air gaps, TL is a length of the optical imaging system along the optical axis from an object-side surface of the first lens to the imaging plane, R1 is a radius of curvature of the object-side surface of the first lens, and f is a focal length of the optical imaging system.

Abstract: A tape film lamination apparatus may include a housing, a substrate holder disposed in the housing and positioned to receive a substrate, a film holder disposed on the housing and positioned to support a tape film, and an air removal unit connected to a portion of the housing below the film holder to remove and/or exhaust air from the housing resulting to attach the tape film to the substrate.

Abstract: A tape film lamination apparatus may include a housing, a substrate holder disposed in the housing and positioned to receive a substrate, a film holder disposed on the housing and positioned to support a tape film, and an air removal unit connected to a portion of the housing below the film holder to remove and/or exhaust air from the housing resulting to attach the tape film to the substrate.