Patent ID: 11860057
Assignee: CHANGCHUN INSTITUTE OF OPTICS, FINE MECHANICS AND PHYSICS, CHINESE ACADEMY OF SCIENCES
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 13:
14. The heterodyne one-dimensional grating measuring method according to claim 13, wherein the step S2 comprises the following steps:
S201: vertically reflecting the first polarized light and the second polarized light to the surface of the one-dimensional measuring grating through a reflecting mirror of the reading head, then generating the +1-order diffracted light and the −1-order diffracted light;
S202: refracting the +1-order diffracted light and the −1-order diffracted light through a refracting lens of the reading head, so that the +1-order diffracted light and the −1-order diffracted light are parallel to each other and are vertically incident to a polarized beam splitting prism of the reading head;
S203: respectively reflecting the first polarized light component of the +1-order diffracted light and the first polarized light component of the −1-order diffracted light to a first quarter wave plate of the reading head through the polarized beam splitting prism; and respectively transmitting the second polarized light component of the +1-order diffracted light and the second polarized light component of the −1-order diffracted light to a second quarter wave plate of the reading head through the polarized beam splitting prism;
S204: respectively converting the first polarized light component of the +1-order diffracted light and the first polarized light component of the −1-order diffracted light into left-handed polarized light, then incidenting the left-handed polarized light to a reflecting prism of the reading head; performing secondary reflection on the first polarized light component of the +1-order diffracted light and the first polarized light component of the −1-order diffracted light through the reflecting prism, so that the first polarized light component of the +1-order diffracted light and the first polarized light component of the −1-order diffracted light become a second P polarized light after passing through the first quarter wave plate, then incidenting the second P polarized light to the polarized beam splitting prism; respectively converting the second polarized light component of the +1-order diffracted light and the second polarized light component of the −1-order diffracted light into right-handed polarized light through the second quarter plate, then incidenting the right-handed polarized light to a compensating mirror of the reading head; reflecting the second polarized light component of the +1-order diffracted light and the second polarized light component of the −1-order diffracted light through the compensating mirror, so that the second polarized light component of the +1-order diffracted light and the second polarized light component of the −1-order diffracted light become a second S polarized light after passing through the second quarter wave plate, then incidenting the second S polarized light to the polarized beam splitting prism;
S205: transmitting the first polarized light component of the +1-order diffracted light and the first polarized light component of the −1-order diffracted light to the photoelectric receiving module through the polarized beam splitting prism after the first polarized light component of the +1-order diffracted light and the first polarized light component of the −1-order diffracted light become the second P polarized light, and reflecting the second polarized light component of the +1-order diffracted light and the second polarized light component of the −1-order diffracted light to the photoelectric receiving module through the polarized beam splitting prism after the second polarized light component of the +1-order diffracted light and the second polarized light component of the −1-order diffracted light become the second S polarized light.