Research On Measuring Guide Straightness Error With Lateral-Modulated Linear Polarized Beam

Guide straightness error can affect the manufacture accuracy of work piece directly. And straightness error measurement is a great important object in industrial measurement.Laser alignment measurement has been paid more and more attention for its easy, lower cost and high accuracy among methods of measuring the guide straightness error. However, with the reference being light intensity, accuracy of traditional alignment measurement is not ideal because the light intensity is easy to be distributed by beam diffraction, light intensity variation and light target's inclination. Polarization state can be considered as a good reference because of its resistant against light intensity and external environment. A measurement with linear polarized light was proposed by our lab. Original modulation for the polarized light is based on magneto-optical modulation which is very complex and expensive to carry out, and the result of that is not ideal. So, a new and simple modulation based on polarization interference is introduced in this paper. And a new method of measuring the guide straightness error with this modulated beam is also introduced correspondingly. Additionally, another new method based on polarization beam splitting is introduced to measure the polarization angle. Advantage of this method is that it can eliminate the effect of light intensity and is easier to carry out.The paper does a deeply analyze in theory for the methods and does a large number of schemes demonstration too. Some experiment parameters such as width of optical slit are made sure through experiment. And an evaluation and error analyze also are finished in the end through experiment. The experiment data shows that the methods are feasible to measure the guide straightness error, and it is worth while to study more deeply.