CN205279996U - Nanometer displacement biometric sensor and detector based on optics doubling of frequency - Google Patents

Abstract

The utility model provides a nanometer displacement biometric sensor and detector based on optics doubling of frequency, including laser instrument, polarization splitting prism, 14 slides, pyramid prism, planar mirror, inclined to one side vibration -damping sheet, photoelectric detector and base. The utility model discloses a sensor adopts optics doubling of frequency technique, directly carries out 8 segmentations with the optical path difference on optical structure, adopts the combination of polarization splitting prism and 14 slides to reduce loss of light energy simultaneously, has guaranteed interference fringe's intensity, has simple structure, and the precision is high, and measuring range is big, interference killing feature characteristics such as strong to compare and to reduce the error that non rectilinear movement caused to a certain extent in one way light beam system. Based on this sensor, the utility model discloses still provide one kind based on the frequency -doubled nanometer displacement detector of optics.

Description

The nanometer displacement gage probe of a kind of optically-based frequency multiplication and detector

Technical field

This utility model relates to field of precision measurement, relates to a kind of high-precision nanometer displacement metering method.

Background technology

Along with the development of science and technology, people are also more and more higher to the required precision of the technology of measurement. Wherein high-precision nanometer displacement metering device becomes the key technology of various fields progressive development. Conventional displacement measurement device is grating scale and laser interferometry instrument. Grating scale is to measure displacement by the Morse's number of interference fringes recording quiet chi and dynamic chi is mutually shifted producing. But grating scale is easily influenced by temperature, Measurement Resolution depends critically upon the grating constant of grating scale, and measurement is limited in scope. The maximum permission speed of single grating scale detection is often inversely proportional to its Measurement Resolution, therefore there is the contradiction of measuring speed and resolution. And laser interferometry instrument is to utilize laser wavelength in a vacuum as length standard, it is possible to reach nano level Measurement Resolution. Utilize the optical path difference para-position shifting measurement of reference path and optical path, can so that the resolution measured reach several nanometers by optical frequency-doubling layout, simultaneously because the coherence length of laser is relatively big, the scope of measurement to be far longer than the measurement scope of grating scale. Patent [CN200910069745.2] relates to a kind of common-path laser interferometer, it includes laser instrument, polarization spectroscope, reflecting mirror, diffraction grating, polaroid, convex lens and photodetector, sending placement polarization spectroscope on beam direction at laser instrument, it is at 45 �� that the light splitting surface of polarization spectroscope and laser instrument send beam direction; The upper side and lower side on the light splitting surface direction of polarization spectroscope places reflecting mirror and diffraction grating respectively; Being sequentially placed polaroid, convex lens and photodetector on the direction of emergent light, the optical axis direction of these three element is at 45 �� with the light splitting surface of polarization spectroscope, and to send beam direction in 90 �� with laser instrument. Laser doppler technique is combined with laser polarization interference technique, strengthens the capacity of resisting disturbance of light path environment to external world, improve measurement resolution and the precision of laser interferometer, but displacement has only been carried out 4 at optical texture and segmented by it.

Summary of the invention

The purpose of this utility model is in that to provide the nanometer displacement gage probe of a kind of optically-based frequency multiplication, and this sensor adopts optical frequency-doubling technology, directly on optical texture, displacement is carried out 8 segmentations, which thereby enhances precision. Adopt polarization splitting prism and the combination of 1/4 slide simultaneously, decrease optical energy loss. Technical solutions of the utility model are as follows:

A kind of nanometer displacement gage probe of optical frequency-doubling, including polarization splitting prism, 1/4 slide, the first plane mirror, the second plane mirror, first prism of corner cube, the second prism of corner cube, the third angle cone prism, fourth angle cone prism and polaroid, it is characterised in that:

It is parallel between relative the first prism of corner cube and fourth angle cone prisms that described polarization splitting prism is placed in two minute surfaces between two parties, and first, the physical dimension of fourth angle cone prism is identical and reflecting surface is each parallel to polarization splitting prism; Described 1/4 slide is arranged on the positive bottom of polarization splitting prism, 1/4 slide work surface is parallel with polarization splitting prism base, 1/4 slide optical center axle is equidistant to the minute surface of first, fourth angle cone prism, is arranged with symmetrical first plane mirror, the second plane mirror below in parallel; First plane mirror is connected with the second prism of corner cube, and the second plane mirror is connected with the third angle cone prism; Second, third prism of corner cube structure described and equivalently-sized, is fixed on up and down motion parts jointly, and second, third prism of corner cube minute surface is coplanar and all upwards relative with the minute surface of first, second plane mirror respectively; Polaroid is arranged on the top of polarization splitting prism; The minute surface of polaroid, 1/4 slide, second, third prism of corner cube minute surface and first, second plane mirror is parallel to each other;

The one end on described polarization splitting prism top is used for laser light incident, and another is rectified polaroid, for laser emitting portion.

During work, incident laser is divided into orthogonal two-route wire polarized light to export by polarization splitting prism, and a road is transmission light T_p, a road is reflection light R_s;

Described transmission light T_pAfter 1/4 slide, reflex to the first plane mirror then through the second prism of corner cube, then under the reflection of the first plane mirror, by original optical path again through 1/4 slide; Twice through 1/4 slide, light beam polarization direction changes 90 degree and becomes reflection light R1, return polarization splitting prism, polarization splitting prism reflex to the first prism of corner cube; Reflex to polarization splitting prism through the first prism of corner cube, reflex to 1/4 slide through polarization splitting prism, be incident to the third angle cone prism, be then reflected to the second plane mirror; Under the second plane mirror effect, again returning through 1/4 slide by original optical path, light beam polarization direction again changes 90 degree and becomes transmission light T2, transmitted through polarization splitting prism, projects on polaroid;

Described reflection light R_sAfter injecting fourth angle cone prism, it is reflected back toward polarization splitting prism, and then is projected on polaroid by polarization splitting prism, interfere after polarization with described transmission light T2;

The optical path difference of two interference lights is relevant with the moving component upper-lower position installing second, third prism of corner cube, change relative to the distance of polarization splitting prism or 1/4 slide with moving component and change, thus causing interference fringe number change, in conjunction with known optical maser wavelength, namely obtain small change in displacement.

Further, the polaroid of described nanometer displacement gage probe be also arranged above photodetector, it is simple to interference light stripe signal receive.

Further, the polaroid of described nanometer displacement gage probe is linear polarization type, realizes the degree of coherence of two-beam by regulating polarization direction.

Further, this utility model is based on described nanometer displacement gage probe, a kind of nanometer displacement detector is proposed, including nanometer displacement gage probe, difference channel, amplification and rectification circuit, Quadrature Decoder/Counter, A/D change-over circuit and computer that the signal of telecommunication successively connects;

Wherein, the interference light stripe signal of described nanometer displacement gage probe output is converted to, through difference channel, the cosine and sine signal that phase contrast is 90 degree, amplification and rectification circuit is sent on one tunnel, becoming Digital Square-Wave to transport to Quadrature Decoder/Counter and carry out four subdivision and count, this circuit counts more than the move of stripe in 1/4 cycle; Another road, through A/D change-over circuit, is finely divided process by A/D converter to less than the move of stripe in 1/4 cycle; The count value of two paths of signals sends into computer, carries out synchronizing addition and processes, Computer calculates shift value.

The technical scheme that the utility model proposes, have employed polarization splitting prism and the combination of 1/4 slide, it is ensured that the intensity of interference fringe, there is measurement scope big, the features such as capacity of resisting disturbance is strong, and the error that on-rectilinear movement causes can be reduced to a certain extent compared to single channel beam system. Owing to have employed the structure of differential type, directly adopting optical frequency-doubling layout, it is achieved optics 8 segments, improve sensitivity, compact conformation can made simultaneously, reduce the impact of temperature, air and mechanical disturbance, it is ensured that the high-precision requirement of measurement.

Accompanying drawing explanation

The structure chart of the nanometer displacement gage probe of Fig. 1 optical frequency-doubling;

Fig. 2 is based on nanometer micrometric displacement detector structure chart of nanometer displacement gage probe;

In all of the figs, identical accompanying drawing labelling is used for representing identical element or structure, wherein:

1-laser instrument, 2-polarization splitting prism, 3-the first prism of corner cube, 4-base, 5-the first plane mirror, 6-the second prism of corner cube, 7-the third angle cone prism, 8-the second plane mirror, 9-1/4 slide, 10-fourth angle cone prism, 11-polaroid.

Detailed description of the invention

In order to make the purpose of this utility model, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, this utility model is further elaborated. Should be appreciated that specific embodiment described herein is only in order to explain this utility model, be not used to limit this utility model. As long as just can be mutually combined additionally, technical characteristic involved in each embodiment of this utility model disclosed below does not constitute conflict each other.

As Fig. 1 shows, the nanometer displacement gage probe of the optical frequency-doubling that this enforcement provides, including laser instrument 1, polarization splitting prism 2,1/4 slide the 9, first plane mirror the 5, second plane mirror 8, first prism of corner cube the 3, second prism of corner cube 6, the third angle cone prism 7, fourth angle cone prism 10, polaroid 11 and base 4.

Laser instrument Output of laser is divided into orthogonal two-route wire polarized light by polarization splitting prism 2, and a road is transmission light T_p, a road is reflection light R_s;

Transmission light T_pAfter 1/4 slide 9, then the first plane mirror 5 is reflexed to through the second prism of corner cube 6, then under the reflection of the first plane mirror 5, again return through 1/4 slide 9 by original optical path, twice through 1/4 slide 9, light beam polarization direction changes 90 degree and becomes reflection light R1, returns polarization splitting prism 2, polarization splitting prism 2 reflexes to the first prism of corner cube 3; Reflex to polarization splitting prism 2 through the first prism of corner cube 3, reflex to 1/4 slide 9 through polarization splitting prism 2, be incident to the third angle cone prism 7, be then reflected to the second plane mirror 8; Under the second plane mirror 8 effect, again return through 1/4 slide 9 by original optical path, twice through 1/4 slide 9, light beam polarization direction changes 90 degree and becomes transmission light T2, transmitted through polarization splitting prism 2, incides polaroid 11;

Reflection light R_sIncide fourth angle cone prism 10, be reflected onto polarization splitting prism 2, and then be reflected onto polarization splitting prism 2, project polaroid 11;

Transmission light T2 and reflection light R_s, after polaroid 11, interfere generation interference fringe. The polarization direction regulating polaroid can make the contrast of interference fringe best.

The laser instrument 1 that this enforcement adopts is helium neon laser, and wavelength is 632.8nm; Polarization splitting prism 2 is GCC-402033 Single wavelength polarization splitting prism, length of side 25.4mm; Prism of corner cube 3,6,7,10 is GCL-030503 prism of corner cube, and minute surface diameter is �� 25.4mm; Quarter wave plate 9 is GCL-0606241/4 wave plate, and minute surface diameter is �� 25.4mm; Polaroid 11 is GCL-050005 polaroid, and minute surface diameter is �� 12.7mm.

When moving component is subjected to displacement, the optical path difference between measuring beam and reference beam changes and causes interference fringe to change. When optical path difference often changes a wavelength, interference fringe is with regard to light and shade alternate once. By to interference fringe counting, small position title value can be obtained.

This enforcement, tested length L when without segmentation:

L=N ��/8

The periodicity of move of stripe when N is mobile tested length L in formula, �� is optical maser wavelength.

Wherein, the interference light stripe signal of described nanometer displacement gage probe output is converted to, through difference channel, the cosine and sine signal that phase contrast is 90 degree, amplification and rectification circuit is sent on one tunnel, becoming Digital Square-Wave to transport to Quadrature Decoder/Counter and carry out four subdivision and count, this circuit can count more than the move of stripe in 1/4 cycle; Another road, through A/D change-over circuit, is finely divided process by A/D converter AD669 to less than the move of stripe in 1/4 cycle; The count value of two paths of signals sends into computer; Carry out synchronizing addition to process, Computer calculate shift value. In conjunction with the effectiveness of actual interference signal, the angular resolution in signal 1/4th cycle is up to 2 ��. Merge the big counting of four segmentations and the subtotal figure of A/D converter segmentation, its displacement measurement resolution:

$\mathrm{\δ}=\frac{\mathrm{\λ}}{8}\×\frac{1}{4}\×\frac{1}{45}\≈0.44nm$

The composition of described nanometer of micrometric displacement detector is as in figure 2 it is shown, include displacement measurement sensor, photodetector, signal processing circuit and computer. Displacement transducer converts the shift value of detection to optical signalling, the signal of telecommunication is converted by photodetection to after being received, the signal of telecommunication sends into computer disposal after signal processing circuit (including amplifying shaping, sensing segmentation and A/D conversion), thus obtaining shift value.

Those skilled in the art will readily understand; the foregoing is only preferred embodiment of the present utility model; not in order to limit this utility model; all any amendment, equivalent replacement and improvement etc. made within spirit of the present utility model and principle, should be included within protection domain of the present utility model.

Claims (5)

1. the nanometer displacement gage probe of an optically-based frequency multiplication, including polarization splitting prism (2), 1/4 slide (9), the first plane mirror (5), the second plane mirror (8), first prism of corner cube (3), the second prism of corner cube (6), the third angle cone prism (7), fourth angle cone prism (10) and polaroid (11), it is characterised in that:

It is parallel between relative the first prism of corner cube (3) and fourth angle cone prisms (10) that described polarization splitting prism (2) is placed in two minute surfaces between two parties, and first, the physical dimension of fourth angle cone prism is identical and reflecting surface is each parallel to polarization splitting prism (2); Described 1/4 slide (9) is arranged on the positive bottom of polarization splitting prism (2), 1/4 slide work surface is parallel with polarization splitting prism (2) base, 1/4 slide optical center axle is equidistant to the minute surface of first, fourth angle cone prism, is arranged with symmetrical first plane mirror (5), the second plane mirror (8) below in parallel; First plane mirror (5) is connected with the second prism of corner cube (6), and the second plane mirror (8) is connected with the third angle cone prism (7); Second, third prism of corner cube structure described and equivalently-sized, is fixed on up and down motion parts jointly, and second, third prism of corner cube (6,7) minute surface is coplanar and all upwards relative with the minute surface of first, second plane mirror respectively; Polaroid (11) is arranged on the top of polarization splitting prism (2); The minute surface of polaroid (11), 1/4 slide (9), second, third prism of corner cube minute surface and first, second plane mirror is parallel to each other;

The one end on described polarization splitting prism (2) top is used for laser light incident, and another is rectified polaroid (11), for laser emitting portion.

2. the nanometer displacement gage probe of optical frequency-doubling according to claim 1, it is characterised in that:

During work, incident laser is divided into orthogonal two-route wire polarized light to export by polarization splitting prism (2), and a road is transmission light T_p, a road is reflection light R_s;

Described transmission light T_pAfter 1/4 slide (9), the first plane mirror (5) is reflexed to then through the second prism of corner cube (6), then under the reflection of the first plane mirror (5), by original optical path again through 1/4 slide (9); Twice through 1/4 slide (9), light beam polarization direction changes 90 degree and becomes reflection light R1, return polarization splitting prism (2), polarization splitting prism (2) reflex to the first prism of corner cube (3); Polarization splitting prism (2) is reflexed to through the first prism of corner cube (3), 1/4 slide (9) is reflexed to through polarization splitting prism (2), it is incident to the third angle cone prism (7), is then reflected to the second plane mirror (8); Under the second plane mirror (8) acts on, again return through 1/4 slide (9) by original optical path, light beam polarization direction again changes 90 degree and becomes transmission light T2, transmitted through polarization splitting prism (2), projects on polaroid (11);

Described reflection light R_sAfter injecting fourth angle cone prism (10), it is reflected back toward polarization splitting prism (2), and then is projected on polaroid (11) by polarization splitting prism (2), interfere after polarization with described transmission light T2;

The optical path difference of two interference lights is relevant with the moving component upper-lower position installing second, third prism of corner cube (6,7), change relative to the distance of polarization splitting prism (2) or 1/4 slide (9) with moving component and change, thus causing interference fringe number change, in conjunction with known optical maser wavelength, namely obtain small change in displacement.

3. nanometer displacement gage probe according to claim 1 and 2, it is characterised in that described polaroid (11) be also arranged above photodetector (12), it is simple to interference light striped receive.

4. nanometer displacement gage probe according to claim 1, it is characterised in that described polaroid (11) is linear polarization type, realizes the degree of coherence of two-beam by regulating polarization direction.

5. the nanometer displacement detector based on gage probe described in claim 3 or 4, it is characterized in that, also include the signal of telecommunication connects successively nanometer displacement gage probe, difference channel, amplification and rectification circuit, Quadrature Decoder/Counter, A/D change-over circuit and computer;

Wherein, the interference light stripe signal of described nanometer displacement gage probe output is converted to, through difference channel, the cosine and sine signal that phase contrast is 90 degree, amplification and rectification circuit is sent on one tunnel, becoming Digital Square-Wave to transport to Quadrature Decoder/Counter and carry out four subdivision and count, this circuit counts more than the move of stripe in 1/4 cycle; Another road, through A/D change-over circuit, is finely divided process by A/D converter to less than the move of stripe in 1/4 cycle; The count value of two paths of signals sends into computer, carries out synchronizing addition and processes, Computer calculates shift value.