A document storage apparatus for safely storing photographs or other documents includes a first transparent sheet and a second sheet attached to the first transparent sheet along a water or air tight seal. The OFDMA system solves a problem that the system performance is deteriorated in uplink communications because subscriber stations have different carrier frequency offsets. Conveniently, the deflector arrays are either liquid crystal phase arrays or reflective MEMS arrays. The elastic structure has an annular member, and the annular member absorbs vibrations and torque fluctuations in the perimeter direction and in the radial direction transmitted from a rotation driving source such as a motor.