Abstract: Provided include a beam modulation apparatus for modulating an input light field and a projection system containing the apparatus. The input light field has a first light field and a second light field, having a difference of 90° in their polarization states. The apparatus includes a PBS prism, a first LCOS panel and a second LCOS panel. The first and the second LCOS panel are respectively over a side surface of the PBS prism opposing to an optical incident surface and an optical exit surface. Each LCOS panel comprises a plurality of pixels over a reflective surface thereof, with each pixel controllably switched on or off such that a polarity state of a light beam reflected by a portion of the reflective surface corresponding thereto is changed or remains unchanged. This beam modulation apparatus can be applied in a projection system, such as a laser TV projection system.

Abstract: A wheel holder assembly includes a mounting frame fixedly mounted inside one bottom hole of the sole of a shoe, a wheel holder frame turned about a shaft in the mounting frame to hold a wheel between a received (the non-operative) position and an extended (the operative) position, a torsional spring adapted to support the wheel holder frame in the extended position, and a spring-supported, press pin-controlled locking device adapted to lock the wheel holder frame between the received position and the extended position.