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|1. (WO2018103695) GENERATION METHOD FOR PROGRAMMABLE ANALOG GRATING WITH EXTENDED DEPTH OF FIELD|
|Applicants:||XI'AN CHISHINE OPTOELECTRONICS TECHNOLOGY CO. LTD.
|Title:||GENERATION METHOD FOR PROGRAMMABLE ANALOG GRATING WITH EXTENDED DEPTH OF FIELD|
Provided is a generation method for a programmable analog grating with an extended depth of field. A laser (2) emits a laser beam (9). After focusing and collimation thereof with a collimating lens (3), a collimated Gaussian laser beam (9) meeting requirements is obtained. The laser beam (9) is reflected by a mirror (4) once, passes through a round diaphragm (8) and is incident on an MEMS galvanometer (5). The beam is reflected by the MEMS galvanometer (5) to the surface of a tested object. The laser (2) is controlled by a sinusoidal current signal generated by a drive board (1) so as to sinusoidally modulate the brightness of the laser beam (9). The MEMS galvanometer (5) is stimulated by a drive signal generated by the drive board (1) to turn two-dimensionally, so as to drive the laser beam (9) to perform scanning, thus generating a grating image (7). A period and a phase of a drive signal of the laser are changed, to obtain grating images (7) with different periods and phases. The grating obtained by the method of the present invention is programmable as a digital grating and has high resolution as a physical grating. The depth of field of the obtained grating is extended ten times or more, and therefore the test range is greatly enlarged.