Abstract: A plurality of laser positioning units are used to position an X-Y stage. In each laser positioning unit, a mirror constantly reflects laser beam to an optical position sensor, where the mirror is integrally mounted on a rotation unit which is integrally mounted on X-Y stage, where the laser diode is mounted on another rotation unit. Each rotation unit includes a fine rotation stage and a coarse rotation stage. When moving the X-Y stage, fine stages constantly rotate mirror or/and laser to reflect the laser beam onto the optical position sensor, the amount of rotations and geometry of position of laser and mirror gives precisely the position of moving stage. The fine stages and coarse stages in different laser positioning units work alternatively to position the stage, and the fine stages are calibrated if coarse stages moves.

Abstract: Two or more laser positioning systems are used to position a moving object. The system includes a laser, mirror or photodiodes sensor on three different rotation units. The unit includes two fine rotation and two coarse rotation stages. By rotating fine stages, the laser on the first rotation unit constantly emits laser beam to a mirror on the second rotation unit which is rigidly mounted on the moving object, the mirror constantly reflects laser beam onto a photodiodes sensor on the third rotation unit. The amount of rotations of fine stages and the geometry among laser, mirror and sensor gives precisely the position of the moving object. After fine rotation stages nearly reach their rotation limit, they return to their starting positions by rotating the coarse rotation stages. The fine stages in different laser positioning systems work alternatively to position a moving object in high precision.

Abstract: Four laser positioning units are used to position and control an X-Y stage which is movable in X and Y directions. For each laser positioning unit, a mirror constantly reflects laser beam to an optical position sensor, where the mirror is integrally mounted on a rotation unit which is integrally mounted on the one side of platform of X-Y stage, where the laser diode is mounted on another rotation unit which is stationary, the optical position sensor is also stationary. Each rotation unit includes a fine rotation stage and a coarse rotation stage, the fine rotation stage has very high resolution but short rotation range, and the coarse rotation stage has a large rotation range but low resolution. When moving the X-Y stage, four fine stages constantly rotate mirror or/and laser to reflect the laser beam onto the optical position sensor, the amount of rotations and geometry of position of laser and mirror gives precisely the position of moving stage.

Abstract: A dental flossing device comprises a handle, two holder elements, a hook, a slider, and a spring. A strand of floss with several tied knots on two open ends generates closed loop of floss. A closed loop of floss is positioned in slots of two holder elements. A reciprocal moving slider connects to a hook, the hook pull the floss against a pressed spring in the handle. When depress the slider, the floss is pulled tightly by the stressed spring. The tightly stretched floss can clean the teeth.

Abstract: A manual hand-held device for shredding partial area of a paper comprising a handler, a punch holder, a punch support, and a punch under which distributes an array of die bars or multi side edged blades is disclosed. The pivoted handler actuates the punch moving vertically by hand force. Paper sheet is fed into the space between holder and the punch support. Selected area of a paper can be shredded into pieces of small dots or strips.