Abstract: A polishing pad includes a pad body; and a transparent window integrally formed in the pad body. The window is formed of a material which is more susceptible to abrasion than a material of the pad body. The pad body has a plurality of grooves formed in a surface thereof, and the window has no grooves in a surface thereof. A surface of the window is recessed with respect to a surface of the pad. The polishing pad prevents a slurry from settling on the window so as to improve the detection precision of the polishing rate. Furthermore, the polishing pad prevents the window from gradually projecting with respect to the pad body by dressing during polishing so as to substantially eliminate adverse effect on the polishing characteristic.

Abstract: A pneumatically movable device with a safety lock means having a movable member, a pneumatic actuator connected to the movable member and adapted to move the movable member and a direction control valve connected to the actuator. A cylinder for locking is connected between one of the ports of the cylinder and the direction control valve. A spring is disposed in the cylinder for locking. Openings provided at a chamber at a side of the spring are connected to the actuator and the directional control valve respectively through a check valve disposed for preventing the air from flowing into the cylinder for locking. Openings provided at a chamber at a side remote from the spring are connected to on one hand to the actuator through a check valve disposed for preventing the air from flowing into the cylinder for locking and on the other hand to the directional valve through the check valve with a restrictor disposed for preventing the air from flowing into the direction control valve.