CN108007363A

CN108007363A - reflective laser grating displacement sensor

Info

Publication number: CN108007363A
Application number: CN201711496955.0A
Authority: CN
Inventors: 杜金昌
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-12-31
Filing date: 2017-12-31
Publication date: 2018-05-08

Abstract

Reflective laser grating displacement sensor, 0.3 ° of parallel lines polarized light source is less than using the angle of divergence, and the incident separation with 2 road light of reflection is completed by polarization splitting prism and quarter wave plate；The light source angle of divergence is less than 0.3 °, the depth of parallelism is high, the component spacing that key light grid move in contrast can be made to reach cm magnitudes, polarization splitting prism is with quarter wave plate to incident high with 2 road light separating degree of reflection, mutual crosstalk is small, thus photoelectric sensor output signals distortion is small, and reaches and improve displacement resolution purpose.

Description

Reflective laser grating displacement sensor

Technical field

The present invention relates to a kind of reflecting light displacement transducer.

Background technology

Grating displacement sensor is divided into transmission-type and reflective 2 kinds, and key light is incided in the light that reflective middle light source is sent Reflected on grid, projected secondary grating afterwards, and injected photoelectric sensor, change into electric signal, afterwards by processing of circuit, draw displacement Data；Current most of reflecting light displacement transducers use LED light source, because LED light source spatial coherence row is poor, key light Grid and secondary grating are close, use semiconductor laser empty as light source, laser usually within 0.06mm, in CN200610065842 Between coherence it is more much higher than LED light source, key light grid can bring up to the cm orders of magnitude with secondary grating space, and key light grid are put down with pair grating Row is placed, light source vertical incidence, and by backtracking, light forms light and shade and become by secondary grating, then by mobile main optical grating reflection The reflected light of change, reflected light is again saturating by secondary grating half, eventually arrives at photoelectric sensor, and fraction is reflected, and by key light Grid reflect, the secondary arrival photoelectric sensor of most Zhongdao, and the optical signal of this second reflection is superimposed upon in the optical signal of first reflection, Interference spurious signal is formed, electric signal waveform distortion is caused, reduces sensor displacement resolution ratio.

The content of the invention

Essential structure light path of the present invention is shown in Fig. 1（Such as Fig. 1）, parallel lines polarized light source of the angle of divergence less than 0.3 °（As 1 in Fig. 1）, Polarization splitting prism（As 3 in Fig. 1）, quarter wave plate（As 4 in Fig. 1）, key light grid（As 5 in Fig. 1）, secondary grating（As 6 in Fig. 1）, light Electric transducer（As 8 in Fig. 1）.

The angle of divergence is less than 0.3 ° of parallel lines polarized light source（As 1 in Fig. 1）Usually semiconductor laser adds plus lens Form, parallel lines polarized light source（As 1 in Fig. 1）By polarization splitting prism（As 3 in Fig. 1）, then by quarter wave plate（In Fig. 1 4）After change into circular polarisation polarised light, circular polarisation polarised light passes through key light grid（As 5 in Fig. 1）Backtracking is pressed after reflection, again By quarter wave plate（As 4 in Fig. 1）Afterwards, the linearly polarized light vertical with incident ray polarization state is changed into, again passes by polarization spectro Prism（As 3 in Fig. 1）When reflected, directive pair grating（As 6 in Fig. 1）, transmitted through secondary grating（As 6 in Fig. 1）Light finally penetrate Enter photoelectric sensor（As 8 in Fig. 1）, photoelectric sensor（As 8 in Fig. 1）Displacement variable is changed into electric signal, by mutually powered-down Displacement is drawn after the processing of road.

Compared with CN200610065842, on a small quantity by secondary grating in the present invention（As 6 in Fig. 1）The light of reflection passes through for 2 times again Quarter wave plate（As 4 in Fig. 1）After can return to light source, it will usually by light source absorb with transmit way in scatter fall, be again introduced into photoelectric transfer Sensor（As 8 in Fig. 1）Component it is few, electric signal waveform distortion will not be caused, be conducive to improve sensor displacement resolution ratio.

The present invention equally uses highly parallel light source, key light grid compared with CN200610065842（As 5 in Fig. 1）With Other light path parts can keep larger spacing, reach as high as cm magnitudes, help to improve sensor interference free performance.

Brief description of the drawings

Fig. 1 is reflective laser grating displacement sensor schematic diagram, and 1 is parallel lines polarized light source, and 3 be polarization spectro rib Mirror, 4 be quarter wave plate, and 5 be main grating, and 6 be secondary grating, and 8 be photoelectric sensor.

Fig. 2 is the reflective laser grating displacement sensor schematic diagram for including polaroid, and 1 is parallel lines polarized light source, 2nd, 7 be polaroid, and 3 be polarization splitting prism, and 4 be quarter wave plate, and 5 be main grating, and 6 be secondary grating, and 8 be photoelectric sensor.

Embodiment

The angle of divergence is less than 0.3 ° of parallel lines polarized light source（As 1 in Fig. 1）Usually semiconductor laser adds plus lens Form, can also be that super-radiance light emitting diode adds plus lens to form.

In parallel lines polarized light source（As 1 in Fig. 2）With polarization splitting prism（As 3 in Fig. 2）Between increase polaroid（Such as figure 2 in 2）, the polarization of light degree of light source output can be improved, in secondary grating（As 6 in Fig. 2）With photoelectric sensor（As 8 in Fig. 1）It Between increase polaroid（As 7 in Fig. 2）Interference luminous intensity can be reduced；Polaroid at 2（Such as in Fig. 22,7）Addition can reduce dry Luminous intensity is disturbed, reduces photoelectric sensor（As 8 in Fig. 1）Electric signal distortion is exported, is conducive to improve sensor displacement resolution ratio.

Claims

1. reflective laser grating displacement sensor, is related to a kind of displacement sensor, it is characterised in that essential structure light path includes The angle of divergence is less than 0.3 ° of parallel lines polarized light source, polarization splitting prism, quarter wave plate, key light grid, secondary grating, photoelectric sensor.

2. reflective laser grating displacement sensor as claimed in claim 1, it is characterised in that parallel lines polarized light source and polarization It there are polaroid between Amici prism.

3. reflective laser grating displacement sensor as claimed in claim 1, it is characterised in that secondary grating and photoelectric sensor it Between there are polaroid.