CN208902043U

CN208902043U - Reflective laser grating displacement sensor

Info

Publication number: CN208902043U
Application number: CN201721916928.XU
Authority: CN
Inventors: 杜金昌
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-12-31
Filing date: 2017-12-31
Publication date: 2019-05-24
Anticipated expiration: 2027-12-31

Abstract

Reflective laser grating displacement sensor, the parallel lines polarized light source using the angle of divergence less than 0.3 ° complete the incident separation with 2 road light of reflection 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 can be made to move in contrast reaches cm magnitude, polarization splitting prism and quarter wave plate are 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 utility model relates to a kind of reflecting light displacement transducers.

Background technique

Grating displacement sensor is divided into transmission-type and reflective 2 kinds, is incident on key light in the light that reflective middle light source issues It is reflected on grid, projected secondary grating afterwards, injected photoelectric sensor, be converted to electric signal, later by processing of circuit, obtain 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 are close with secondary grating, use semiconductor laser as light source usually within 0.06mm, in CN200610065842, and laser is empty Between coherence it is more much higher than LED light source, the cm order of magnitude can be improved in key light grid and secondary grating spacing, and key light grid and secondary grating are flat Row is placed, light source vertical incidence, and by backtracking, light passes through secondary grating, using mobile main optical grating reflection, is formed light and shade and is become The reflected light of change, it is saturating that reflected light passes through secondary grating half again, eventually arrives at photoelectric sensor, fraction is reflected, and by key light The optical signal of grid reflection, the secondary arrival photoelectric sensor of most Zhongdao, this second reflection is superimposed upon in the optical signal of first reflection, Interference spurious signal is formed, causes electric signal waveform to be distorted, reduces sensor displacement resolution ratio.

Utility model content

The utility model essential structure optical path is shown in Fig. 1 (such as Fig. 1) that polarization splitting prism (as shown in figure 1 3) position is in parallel lines Between polarized light source (as shown in figure 1 1) and quarter wave plate (as shown in figure 1 4), quarter wave plate (as shown in figure 1 4) and key light grid (as shown in figure 1 5) Adjacent, photoelectric sensor (as shown in figure 1 8) exists in polarization splitting prism (as shown in figure 1 3) side, secondary grating (as shown in figure 1 6) position Photoelectric sensor (as shown in figure 1 8) is between polarization splitting prism (as shown in figure 1 3)；Parallel lines polarized light source (as shown in figure 1 1) issues Parallel linearly polarized light pass through polarization splitting prism (as shown in figure 1 3), using being converted to entelechy after quarter wave plate (as shown in figure 1 4) Change polarised light, directive key light grid (as shown in figure 1 5), circular polarisation polarised light is returned by key light grid (as shown in figure 1 5) reflection road Hou Anyuan It returns, it is secondary after quarter wave plate (as shown in figure 1 4), it is converted to the linearly polarized light vertical with incident ray polarization state, secondary process It is reflected, is projected by polarization splitting prism (as shown in figure 1 3) side, directive secondary grating inside polarization splitting prism (as shown in figure 1 3) (as shown in figure 1 6), the light transmitted through secondary grating (as shown in figure 1 6) finally inject photoelectric sensor (as shown in figure 1 8), photoelectric sensor The light and shade optical signal that (as shown in figure 1 8) generate when key light grid (as shown in figure 1 5) and secondary grating (as shown in figure 1 6) relative displacement are changed It is converted to electric signal, obtains displacement after being handled by interlock circuit.

Parallel lines polarized light source (as shown in figure 1 1) requires the angle of divergence less than 0.3 °, and usually semiconductor laser adds convergence saturating Mirror is constituted.

Compared with CN200610065842, on a small quantity by light 2 times again of secondary grating (as shown in figure 1 6) reflection in the utility model Light source can be returned to after quarter wave plate (as shown in figure 1 4), it will usually which scattering is fallen on the way with transmission by light source absorption, is again introduced into light The component of electric transducer (as shown in figure 1 8) is few, not will cause electric signal waveform distortion, is conducive to improve sensor displacement resolution Rate.

The utility model is compared with CN200610065842, and the same light source parallel using height, key light grid are (as shown in figure 1 5) larger spacing can be kept with other light path parts, reaches as high as cm magnitude, helps to improve sensor interference free performance.

Detailed description of the invention

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, 2,7 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.

Specific embodiment

Parallel lines polarized light source (as shown in figure 1 1) of the angle of divergence less than 0.3 ° is usually that semiconductor laser adds plus lens It constitutes, can also be that super-radiance light emitting diode adds plus lens to constitute.

Increase polaroid between parallel lines polarized light source (1 in such as Fig. 2) and polarization splitting prism (3 in such as Fig. 2) (as schemed In 2 2), the polarization of light degree that light source output can be improved, secondary grating (6 in such as Fig. 2) and photoelectric sensor (as shown in figure 1 8) it Between increase polaroid (7 in such as Fig. 2) interference luminous intensity can be reduced；Polaroid (2,7 in such as Fig. 2) addition can reduce dry at 2 Luminous intensity is disturbed, photoelectric sensor (as shown in figure 1 8) output electric signal distortion is reduced, is conducive to improve sensor displacement resolution ratio.

Claims

1. reflective laser grating displacement sensor is related to a kind of displacement sensor, which is characterized in that polarization splitting prism position Between parallel lines polarized light source and quarter wave plate, quarter wave plate is adjacent with key light grid, and photoelectric sensor is in polarization splitting prism side Face, secondary grating position is in photoelectric sensor between polarization splitting prism；The parallel linearly polarized light that parallel lines polarized light source issues By polarization splitting prism, using circular polarisation polarised light, directive key light grid is converted to after quarter wave plate, circular polarisation polarised light is passed through It crosses by backtracking after main optical grating reflection, it is secondary after quarter wave plate, it is converted to the linear polarization vertical with incident ray polarization state Light, it is secondary by being reflected inside polarization splitting prism, it is projected by polarization splitting prism side, directive secondary grating, transmitted through pair The light of grating finally injects photoelectric sensor.

2. reflective laser grating displacement sensor as described in claim 1, which is characterized in that parallel lines polarized light source and polarization There are polaroids between Amici prism.

3. reflective laser grating displacement sensor as described in claim 1, which is characterized in that secondary grating and photoelectric sensor it Between there are polaroids.