A Linear Displacement Measuring System Based on Alternating Light Field

Abstract

The invention discloses a linear displacement measurement system based on an alternating light field. The system comprises a light emitting element, a fixed scale substrate, a movable scale substrate,a photoelectric detector and an electronic signal processing circuit, wherein a row of fixed scale illuminating surfaces are arranged on the fixed scale substrate, the light emitting element comprises an alternating light source, the alternating light source is driven by an alternating excitation signal to form a single alternating light field, four rows of movable scale illuminating surfaces arranged on the movable scale substrate are completely covered by the single alternating light field in a direction perpendicular to the alternating light source, the photoelectric detector comprises four photoelectric detection heads, and the four photoelectric detection heads can receive all luminous flux of the four rows of movable scale illuminating surfaces independently at the same time. The light emitting element, the photoelectric detector and the movable scale substrate can move together relative to the fixed scale substrate, four photoelectric current signals output by the four photoelectric detection heads are input to the electronic signal processing circuit, and after processing is conducted, a linear displacement value of the movable scale substrate relative to the fixed scale substrate is obtained. By means of the linear displacement measurement system based on the alternating light field, precise linear displacement measurement can be achieved, meanwhile, the measurement system size is reduced, and integration is more facilitated.

Description

technical field [0001] The invention relates to a linear displacement measurement system, in particular to a linear displacement measurement system based on an alternating light field. Background technique [0002] In the field of precision displacement measurement, the grating is restricted by advanced manufacturing technology, light wavelength and optical diffraction limit, and it is difficult to further improve the measurement accuracy. The time grating is a displacement sensor that uses clock pulses as the reference for displacement measurement. Patent CN104655023A discloses a single-row time grating linear displacement sensor based on the construction of a moving light field. It adopts a single-row half-sine transmission through four light sources The signal formed on the surface is synthesized into two standing wave signals, and then a traveling wave signal is synthesized by an adding circuit to realize the measurement of linear displacement. This time grating linear ...

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Problems solved by technology

This time grating linear displacement sensor has the following problems: (1) The amplitude, phase, scattering angle and uniformity of the four-way alternating light source signals are uncontrollable, which makes it difficult to obtain high-quality traveling waves, thereby restricting the measurement accuracy; ( 2) All four light sources need to be collimated, which makes the overall volume of the sensor probe large, which is not conducive to integration and high cost; (3) a single row of half-sine light-transmitting surface is used, the luminous flux is small, and there is insufficient compensation for inclination errors, and the installation High standard

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