Abstract: A light tunnel for use in an optical projection system, comprising: a plurality of reflecting plates, each said reflecting plate being disposed between and connected to the other two said reflecting plates, so that a light passage with a hollow structure is defined by said plurality of reflecting plates. At least one of said reflecting plates has a first surface in an inclined structure, said reflecting plate having said first surface is disposed between and obliquely connected to the other two said reflecting plates for forming said light passage having a non-rectangular cross section, and said first surface of said reflecting plate is abutted against an adjoined reflecting plate to form a junction with no gap between said first surface of said reflecting plate and said adjoined reflecting plate.

Abstract: A clamp is provided. The clamp comprises a frame and a movable structure. The movable structure is detachably connected with the frame to define a receiving space for receiving at least one substrate. After sliding along a surface of the frame to a suitable position, the movable structure is adapted to be fastened together with the frame to fix the at least one substrate in the receiving space.

Abstract: A light tunnel for use in an optical projection system, comprising: a plurality of reflecting plates, each said reflecting plate being disposed between and connected to the other two said reflecting plates, so that a light passage with a hollow structure is defined by said plurality of reflecting plates. At least one of said reflecting plates has a first surface in an inclined structure, said reflecting plate having said first surface is disposed between and obliquely connected to the other two said reflecting plates for forming said light passage having a non-rectangular cross section, and said first surface of said reflecting plate is abutted against an adjoined reflecting plate to form a junction with no gap between said first surface of said reflecting plate and said adjoined reflecting plate.

Abstract: A burglarproof device comprises a carrier, two conductors and an electric shock unit. The carrier is equipped with locators for hanging the carrier. The carrier and the locators are insulators. The electric shock unit comprises a high voltage generator, a power supplier and an initiator. The high voltage generator is supplied with power from the power supplier to boost voltages. The initiator is triggered by a switch. With the device, arc light and electric shock sound are uniformly generated between the two conductors while conducting electricity.

Abstract: A clamp is provided. The clamp comprises a frame and a movable structure. The movable structure is detachably connected with the frame to define a receiving space for receiving at least one substrate. After sliding along a surface of the frame to a suitable position, the movable structure is adapted to be fastened together with the frame to fix the at least one substrate in the receiving space.