The LS 1 and LS 10 laser pick-ups are particularly suited for noncontact surface texture measurements of testpieces with plane or curved surfaces made of sensitive materials (e.g. surfaces of fluids, glass, rubber, coal, varnish, wax coatings, special paper types, plastics, and soft metals) or elastic materials such as thin foils.
The LS 1 and LS 10 laser pick-ups are skidless pick-ups to be used in stylus instruments featuring a datum plane. They have a measuring range of ± 250 µm (± .00984 in) which can optionally be enlarged to ± 300 µm (± .0118 in).
The LS 1 pick-up features a measuring distance of 1 mm (.0394 in) between the testpiece surface and the outlet of the laser beam. Due to its larger measuring distance of 10 mm (.394 in), the LS 10 pick-up is set up easily. It is also particularly suited for measuring recessed surfaces.
The pick-up is mounted to the PRK or PGK 120 drive units.

Measuring principle

The LS 1 and LS 10 laser pick-ups work on the principle of dynamic focussing:
The infrared light of a laser diode is brought into a parallel beam and then guided to the objective. The objective focusses the beam in such a way that 1 mm (.0394 in; with LS 1) or 10 mm (.394 in; with LS 10), respectively, below the outlet, it forms a measuring spot (focus) with a diameter of approx. 2 µm (80 µin) on the testpiece surface.
The light reflected by the surface is assessed by the objective and directed to a focus detector. The focus detector converts the optical signal into an electrical one which contains information on the distance from the optical system to the testpiece surface. A linear motor moves the objective so that the laser beam is always correctly focussed on the testpiece surface.
As with mechanical pick-ups, the position of the objective is converted into an electrical signal via an inductive position transducer, this signal then being processed by the Perthometer.