Laser encoder introduces picometer resolution

Fiberoptic laser encoder system sets a new standard for precision with a resolution capability of 40 picometers, sub-nanometer non-linearity, and part-per-billion laser-frequency stability.

Renishaw's new RLE20 fiberoptic laser encoder system sets a new standard for precision and convenience with a resolution capability of 40 picometers, sub-nanometer non-linearity, and part-per-billion laser-frequency stability.

The system brings the advantages of a fiber-optic-launched laser encoder to precision motion system manufacturers and semiconductor equipment OEMs producing wafer inspection, lithography and other yield enhancement tools that must handle smaller feature sizes in a reduced machine footprint.

The RLE20 utilises the same architecture as the established RLE10, with a laser source being connected to a detector head by a 3m fiberoptic cable.

The fiberoptic launch system allows exceptional application convenience, with only two components to be aligned to form a complete axis positioning system.

Installation time and equipment footprint can be significantly reduced.

All Renishaw RLE laser systems provide positional output signals in differential digital RS422 and/or 1 Vpp sine/cosine formats.

Digital output signals provide resolutions of up to 10nm, while analogue signals can be used in conjunction with Renishaw's RGE interpolators or the new RPI20 parallel interface to provide resolutions of 0.39 nanometers and 40 picometers respectively.

To counter refractive index changes due to atmospheric conditions, Renishaw offers the RCU10 compensation system.

Taking readings from the RLE system and environmental data from its sensors, the RCU10 modifies 'raw' position feedback signals before supplying corrected data to the motion controller to maintain accuracy under fluctuating environmental conditions.

(Interferometric measurement is based on the wavelength of laser light.

Changes in air temperature, pressure and humidity affect its refractive index, and hence the wavelength of any laser light traveling through it.

The RCU10 corrects for this.

The increasing range of interferometer solutions from Renishaw now includes multiple laser sources and interferometers for use in linear, X-Y (planar) and differential measurement applications.

This comprehensive range of flexible interferometer solutions is further enhanced by a comprehensive 24-month warranty.

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