The invention discloses a light projection device used for the three-dimensional measurement of an object surface. Laser generated by a laser generates polarized light through an optical expansion unit, a mirror and a first polarizing piece. The polarized light is projected to front and back surfaces of a first sensitive optical flat plate, and forms two light paths through the sensitive optical flat plate. The first light path forms vertical polarized light through a second polarizing piece, and the vertical polarized light is projected onto a second sensitive optical flat plate through a first optical wedge pair. The second light path forms vertical polarized light through a third polarizing piece, and the vertical polarized light is projected onto the second sensitive optical flat plate through a second optical wedge pair. Two light paths form combined beam through the second sensitive optical flat plate, and the combined beam is enlarged sequentially through a 1/4 wave piece, an adjustable polarizing piece and a projection objective, and is projected onto the measured object surface. According to the invention, a polarization technology and a phase shift stripe technology are combined; the three-dimensional topography of the surface of various objects of different structures is measured by a machine/off-machine; and the light projection device has strong abilities of vibration resistance and noise dynamic, and especially has strong robustness for the surface measurement of molds with complex structures.

Light projection device used for three-dimensional measurement of object surface

The invention relates to the field of optical measurement, in particular to a wavefront extraction algorithm and a shearing interferometer of using the same. The wavefront extraction algorithm comprises the steps of dividing a phase difference of an x coordinate into a first odd-order item and a first even-order item; calculating the even-order item and odd-order item of a wavefront of the x coordinate separately; and finally calculating the sum of the even-order item, the odd-order item and the wavefront of a y axis. The wavefront can be obtained and the extraction process is effectively simplified. The corresponding shearing interferometer adjusts a phase shift of a to-be-measured beam only through a beam splitting cube, so that extraction of the wavefront of an ultrafast beam is achieved, the structure of the interferometer is simplified and wavefront extraction of a laser beam is simpler.

Wavefront extraction algorithm and shearing interferometer of using same

The utility model provides a polarization phase shift double-cut interference wave surface measuring apparatus, comprising a first pressure-sensitive parallel plate, a left and below wedge-shaped optical plate, a left and upper wedge-shaped optical plate, a right and below wedge-shaped optical plate, a right and upper wedge-shaped plate, a second pressure-sensitive parallel plate, a polarization phase shifter, an imaging lens and an image sensor which are arranged along the direction of advance of the light beam in sequence; wherein, an output terminal of the image sensor is connected with a computer. The utility model not only has all the characteristics of the double-cut interference surface measuring apparatus, but also has the advantages that the sensitivity is high, any symmetrical wave surface can be accurately measured, the intact wave surface outline can be given and so on.

Polarized phase shift double shearing interference wave surface measuring apparatus

The swing mechanism includes mirror base, bracing frame. The bracing frame is composed of a support rack, left and right swing frames setup with same structure at two side of the support rack. The left swing frame includes two pillars, up sheet support, and low sheet support. Through two pillars, outer sides of the up and low sheet supports are connected to each other fixedly. Through up and low two bearings, the side near to the support rack connected to middle upright post. Being matched to outline size of mirror base, hole of mirror base is made in middle of the up and low sheet supports. Elastic fastening parts are setup on the up sheet support, and low sheet support. Hole of mirror base is in use for mirror base to be placed. Banking screw is setup on left and right swing frames. The invention is suitable to setting up dual optical flat in large aperture. Position control is carried out in direction perpendicular to swing plane. Features are: simple structure and compact.

Double optic flat plate swing mechanism

The disclosed collimator is composed of primary mirror, beam-splitter mirror, and secondary mirror. Both primary mirror and secondary mirror possess positive focal power. The primary mirror possesses long focal length. Being located in front of the back focus of the primary mirror, the beam-splitter mirror is placed in 45 degrees with the optical axis of the primary mirror. Being setup at reflected light path of the beam-splitter mirror, the secondary mirror is located in front of the focus at reflected light path formed by the primary mirror. The primary mirror and the beam-splitter mirror is an aberration-eliminated combination. Being applicable to ground detection and verification device of laser communication terminal, the invention meets requirement of big viewing field for capturing, tracking and detecting purposes, as well as meets requirement of long focal length for tracking and aiming purposes in high precision. Features are: simple structure and easy of operation.

Jianfeng Sun

Papers

Polarized phase shift double shearing interference wave surface measuring apparatus

Double optic flat plate swing mechanism

Bifocus parallel collimator