Abstract: A portable projector screen assembly includes a roller, two cylinders slidably connected to two ends of the roller respectively, a collapsible member connected to the roller, and a screen. The collapsible member includes a plurality of interconnected pieces. Two free ends of the collapsible member are fixed to free ends of the cylinders respectively. The screen includes a plurality of fixing portions, and the fixing portions are respectively connected to joints of each two pieces of the collapsible member.

Abstract: A projector screen includes one or more markers that are configured to be usable by projection processing circuitry in order to calculate a user perceived distortion in an image to be projected on the projector screen.

Abstract: A magnet rotor includes a drive arm with a rotary shaft and a hollow cylindrical-shaped permanent magnet bonded by a light curable resin. The drive arm is composed of a light transmitting resin, and the permanent magnet is an anisotropic magnet with an axis of easy magnetization. During fabrication, the light curable resin is applied to the rotary shaft, and a hollow portion of the magnet is fitted to the rotary shaft. While holding the magnet in a position where a direction of the axis of easy magnetization corresponds to a magnetic field direction, the drive arm is irradiated with light to cure the resin and bond the drive arm and the permanent magnet.