CN201421325Y - Optical path collimation sighting device of laser interferometer - Google Patents
Optical path collimation sighting device of laser interferometer Download PDFInfo
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- CN201421325Y CN201421325Y CN2009201724113U CN200920172411U CN201421325Y CN 201421325 Y CN201421325 Y CN 201421325Y CN 2009201724113 U CN2009201724113 U CN 2009201724113U CN 200920172411 U CN200920172411 U CN 200920172411U CN 201421325 Y CN201421325 Y CN 201421325Y
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- laser
- quadrant
- laser interferometer
- quadrants
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Abstract
An optical path collimation sighting device of a laser interferometer is characterized in that a four-quadrant detector is fixedly arranged on the reflecting surface of a target lens, the four-quadrant detector are four photodiodes which have the same performances, utilize 'O'-point as the original point of a coordinate according to the mode of a rectangular co-ordinate, and are arrayed into fourquadrants, the photosensitive surface of each photodiode orientates to a laser, the photodiodes in the four quadrants are respectively used as a light intensity detector of each quadrant, an arithmetic circuit is arranged, and a laser light spot horizontal displacement signal X value and a laser light spot vertical displacement signal Y value are respectively output from the arithmetic circuit. The optical path collimation sighting device of the laser interferometer can quantitatively, quickly and accurately achieve the adjustment of an interference optical path, thereby lowering the influenceof cosine error to a measuring system.
Description
Technical field
The utility model relates to the laser interferometer measurement light path alignment sighting device, is used for precision measurement and precise measurement technique field.When adopting laser interferometer to carry out linear measure longimetry, be used for realizing rapidly and accurately the collimation aiming of laser interferometer measurement light path and target mirror moving direction.
Background technology
Along with developing by leaps and bounds of modernized national defense construction, commercial production and science and technology, people propose more and more higher requirement to the precision and the measuring speed of displacement measurement and location and demarcation.Laser interferometer measurement precision height can reach the nanoscale measuring accuracy, the resolution height, and measuring speed is fast, and range is big, extensively is used in precision or the ultra precise measurement.But, in the linear measure longimetry of laser interferometer is used, for the linear measure longimetry precision with laser interferometer is complementary, realize the nanometer scale measuring accuracy, must make the measurement light path of laser interferometer and the direction of motion of measurand, the target mirror direction of motion that is laser interferometer is consistent as far as possible, just collimates, otherwise can produce the cosine error of can not ignore.
Laser interferometer commonly used at present, no matter be single frequency laser interferometer or two-frequency laser interferometer, precision all reaches nanoscale, the 5529A two-frequency laser interferometer of HP for example, its precision can reach 1.7ppm when linear measurement, promptly in 1 meter measurement range, its measuring accuracy is 1.7 μ m.; when interferometer measurement direction and target mirror moving direction have certain angular deviation; as: 10 ' deviation can make measurement result and actual value differ 4.2 μ m; be that cosine error reaches 4.2 μ m; this error amount is far longer than the measuring accuracy of interferometer itself, this shows that the laser interferometer measurement direction is very big because of not aiming at the measuring error that causes with target mirror moving direction.In order to reduce this cosine error, before measurement, need regulate measuring light path, make interferometer measurement direction and target mirror moving direction point-blank, reduce cosine error, the measuring accuracy of measuring accuracy and laser interferometer is complementary.To be the attemperator beat hot spot on the target mirror by the visual inspection laser instrument to way at present commonly used, whether take place up and down with the motion of target mirror or about skew, judge thus direction that the target mirror moves whether with the direction of interferometer measurement point-blank, and on this basis light path is adjusted.But this method can only be judged the deviation between the both direction qualitatively, and the observer also can only infer the adjustment direction of target mirror and general setting range, and can not accurately determine.In practical operation, because the least displacement that human eye can be differentiated has only 0.1mm, make the artificial precision of adjusting often not reach actual requirement, in actual measurement, especially telemeasurement, very trickle angular deviation all can produce very big influence to measurement result.Table 1 is depicted as the influence of the angular deviation θ of the direction of measurement of laser interferometer and target mirror moving direction to measurement result.
Table 1
The utility model content
The utility model is for avoiding above-mentioned existing in prior technology weak point, a kind of light path alignment sighting device for laser interferometer is provided, fixing batsh production on a periodic basis and realize the adjustment of optical interference circuit quickly and accurately, thus reduce the influence of cosine error to measuring system.
The utility model technical solution problem adopts following technical scheme:
The design feature of the utility model light path alignment sighting device for laser interferometer is to fixedly install 4 quadrant detector on the reflecting surface of target mirror, described 4 quadrant detector is the mode of the identical photodiode of four performances according to rectangular coordinate, with " O " point is true origin, be arranged in first quartile, second quadrant, third quadrant and four-quadrant, the photosurface of each photodiode is towards laser instrument; With the photodiode in described four quadrants is respectively as the light intensity detector of each quadrant, respectively with the corresponding output of each photodiode all quadrants light intensity current signal I
1, I
2, I
3, I
4The electrical signal conversion circuit is set, described all quadrants light intensity current signal after the electrical signal conversion circuit with all quadrants voltage signal U
1, U
2, U
3, U
4Corresponding output; Computing circuit is set, and exporting laser facula horizontal shift signal X in described computing circuit respectively is (U
1+ U
4)-(U
2+ U
3) and laser facula perpendicular displacement signal Y be (U
1+ U
2)-(U
3+ U
4).
The method of sight of the utility model light path alignment sighting device for laser interferometer is to carry out as follows:
Step 1: before the collimation aiming of carrying out optical interference circuit, the target mirror is fixed on the initial position, adjust laser positions, make the initial laser hot spot horizontal shift signal X1 and the initial laser hot spot perpendicular displacement signal Y1 that export by arithmetical unit be zero, thus the laser instrument output light path is aimed on the position of described origin " O ";
Step 2: by target mirror moving direction the target mirror is moved, move back laser facula horizontal shift signal X2 by arithmetical unit output target mirror, the target mirror moves back laser facula perpendicular displacement signal Y2;
Step 3: if X2 and Y2 are zero, the direction of measurement that then is judged as laser interferometer is consistent with the direction that the target mirror moves; If X2 and Y2 are non-vanishing, then obtain angular deviation between the laser interferometer measurement direction of required adjustment and the direction that the target mirror moves according to X2 and Y2.
When the direction that moves when laser interferometer measurement direction and target mirror was consistent, moving of target mirror can not make the hot spot that is radiated on the 4 quadrant detector take place up and down or the skew of left and right directions, so the light intensity current signal I of 4 quadrant detector output
1, I
2, I
3, I
4Remain unchanged, laser facula horizontal shift signal X and laser facula perpendicular displacement signal Y after handling through arithmetical unit also remain zero.
When the direction that moves when laser interferometer measurement direction and target mirror had angular deviation, along with moving of target mirror, the hot spot that is radiated on the 4 quadrant detector was offset, the light intensity current signal I that this moment, 4 quadrant detector was exported
1, I
2, I
3, I
4Also can change accordingly, obtain laser facula horizontal shift signal X and laser facula perpendicular displacement signal Y respectively by arithmetical unit, again through follow-up Filtering Processing and analog to digital conversion, finally can directly read the angular deviation of the direction that laser interferometer measurement direction and target mirror move by computing machine.
Compared with the prior art, the utility model beneficial effect is embodied in:
1, utilize the utility model light path alignment sighting device for laser interferometer and method of sight can read the bias direction and the size of laser interferometer measurement direction and target mirror moving direction rapidly and accurately, thereby the adjustment that the handled easily person carries out pitching and deflects laser instrument realizes the collimation aiming of laser interferometer measurement light path and target mirror moving direction.
2, the utility model employing 4 quadrant detector replacement human eye comes the offset information of detection laser hot spot, has improved the resolution of detection system greatly; Effectively avoided simultaneously human eye Direct observation laser, eliminated laser power and cross by force the injury that may cause human eye.
Description of drawings
Fig. 1 is the utility model 4 quadrant detector structural representation; Wherein, Fig. 1 a is laser facula and detector center misalignment view; Fig. 1 b is laser facula and detector centrally aligned view.
Number in the figure: 1 for first quartile detector, 2 is that second quadrant detector, 3 is the third quadrant detector, and 4 is that 4 quadrant detector, 5 is a laser facula.
Fig. 2 is the utility model circuit theory diagrams.
Below by embodiment, the utility model is described in further detail in conjunction with the accompanying drawings:
Embodiment
Referring to Fig. 1, the light path alignment sighting device for laser interferometer structure in the present embodiment is set to:
On the reflecting surface of target mirror, fixedly install 4 quadrant detector, be first quartile detector 1, second quadrant detector 2, third quadrant detector 3 and 4 quadrant detector 4: 4 quadrant detector is the mode of the identical photodiode of four performances according to rectangular coordinate, with " O " point is true origin, be arranged in the the 1st, the 2nd, the 3rd and the 4 four quadrant, the photosurface of each photodiode is towards laser instrument; With the photodiode in four quadrants is respectively as the light intensity detector of each quadrant, respectively with the corresponding output of each photodiode all quadrants light intensity current signal I
1, I
2, I
3, I
4The electrical signal conversion circuit is set, all quadrants light intensity current signal after the electrical signal conversion circuit with all quadrants voltage signal U
1, U
2, U
3, U
4Corresponding output; Computing circuit is set, and exporting laser facula horizontal shift signal X in computing circuit respectively is (U
1+ U
4)-(U
2+ U
3) and laser facula perpendicular displacement signal Y be (U
1+ U
2)-(U
3+ U
4), this signal X and Y just can directly obtain the offset information of laser interferometer measurement direction and target mirror moving direction after follow-up filtering and analog to digital conversion by Computer Processing.
The method of sight of light path alignment sighting device for laser interferometer is to carry out as follows in the present embodiment:
Step 1: before the collimation aiming of carrying out optical interference circuit, with the target mirror fixedly on the initial position, adjust laser positions, make the initial laser hot spot horizontal shift signal X1 and the initial laser hot spot perpendicular displacement signal Y1 that export by arithmetical unit be zero, thus the laser instrument output light path is aimed on the position of described origin " O "; At this moment, the light intensity current signal equal and opposite in direction of 4 quadrant detector output.
Step 2: by target mirror moving direction the target mirror is moved, move back laser facula horizontal shift signal X2 by arithmetical unit output target mirror, the target mirror moves back laser facula perpendicular displacement signal Y2;
Step 3: if X2 and Y2 are zero, the direction of measurement that then is judged as laser interferometer is consistent with the direction that the target mirror moves; If X2 and Y2 are non-vanishing, then obtain angular deviation between the laser interferometer measurement direction of required adjustment and the direction that the target mirror moves according to X2 and Y2.
Shown in Figure 1, laser beam shines on the photosurface of 4 quadrant detector after passing through optical system, forms the hot spot that certain size is arranged, and makes the photodiode of four quadrants distinguish the output intensity electric current I
1, I
2, I
3, I
4If the position of this spot center in the horizontal direction with vertical direction on side-play amount be respectively Δ x and Δ y, as shown in Figure 1a; When the system optical axis alignment coordinates initial point " O " at laser instrument place, the center of circular light spot overlaps with the four-quadrant center, i.e. Δ x=0, and Δ y=0 is shown in Fig. 1 b.At this moment, four quadrants are subjected to the facula area of photograph identical, the light intensity electric current I of output
1, I
2, I
3, I
4Equal and opposite in direction.Because light intensity electric current I
1, I
2, I
3, I
4Amplitude is less, need be converted to voltage U through operational amplifier
1, U
2, U
3, U
4Utilize voltage U
x, U
yRepresent the offset information of spot center horizontal direction and vertical direction, see formula (1) and formula (2)
U
x＝U
1+U
4-(U
2+U
3)(1)
U
y＝U
1+U
2-(U
3+U
4)(2)
U in the formula
1, U
2, U
3, U
4Photo-signal I for four-quadrant output
1, I
2, I
3, I
4The voltage signal that is converted to through operational amplifier.In order to eliminate laser instrument self variable power to U
x, U
yInfluence, usually, divided by U
Sum, wherein
U
sum＝U
1+U
2+U
3+U
4(3)
U in the formula
SumBe four quadrants output photocurrents change into magnitude of voltage and.
With U
xAnd U
yDivided by U
SumAfter, spot center horizontal direction and vertical offset information Δ x after laser instrument self variable power that the is eliminated influence, the equivalent signal of Δ y is used ε respectively
xAnd ε
yFormula (4) and formula (5) are seen in expression, are four-quadrant plus-minus derivation algorithm,
ε in the formula
xDisplacement signal for horizontal direction; ε
yDisplacement signal for vertical direction.Thus can corresponding glossing up up and down or the distance of move left and right, and the angular deviation of concrete measurement range inner laser interferometer measurement direction and target mirror moving direction.
The HP5529A two-frequency laser interferometer is used in experiment at present embodiment, its spot diameter is 6mm, and signal is ± 10V that the amplitude of noise is 10mV through the amplitude after the processing of circuit, the minimum resolution of system can reach 1.2 μ m, and the resolution of comparing human eye has improved 80 times.
According to circuit shown in Figure 2, as long as the spectral response range of 4 quadrant detector is complementary with the wavelength of laser instrument, just can obtain stable output, and with the big or small also onrelevant of laser facula.
Claims (1)
1, light path alignment sighting device for laser interferometer, it is characterized in that on the reflecting surface of target mirror, fixedly installing 4 quadrant detector, described 4 quadrant detector is the mode of the identical photodiode of four performances according to rectangular coordinate, with " O " point is true origin, be arranged in first quartile, second quadrant, third quadrant and four-quadrant, the photosurface of each photodiode is towards laser instrument; With the photodiode in described four quadrants is respectively as the light intensity detector of each quadrant, respectively with the corresponding output of each photodiode all quadrants light intensity current signal I
1, I
2, I
3, I
4The electrical signal conversion circuit is set, described all quadrants light intensity current signal after the electrical signal conversion circuit with all quadrants voltage signal U
1, U
2, U
3, U
4Corresponding output; Computing circuit is set, and exporting laser facula horizontal shift signal X in described computing circuit respectively is (U
1+ U
4)-(U
2+ U
3) and laser facula perpendicular displacement signal Y be (U
1+ U
2)-(U
3+ U
4).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201724113U CN201421325Y (en) | 2009-06-03 | 2009-06-03 | Optical path collimation sighting device of laser interferometer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201724113U CN201421325Y (en) | 2009-06-03 | 2009-06-03 | Optical path collimation sighting device of laser interferometer |
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|---|---|
| CN201421325Y true CN201421325Y (en) | 2010-03-10 |
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|---|---|---|---|
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| Country | Link |
|---|---|
| CN (1) | CN201421325Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102866138A (en) * | 2012-09-13 | 2013-01-09 | 北京瑞利分析仪器有限公司 | Four-quadrant detector-based auxiliary system and method for atomic fluorescence hollow cathode lamp |
| CN109974592A (en) * | 2019-03-28 | 2019-07-05 | 南京工程学院 | A kind of part size detection device and its detection method |
-
2009
- 2009-06-03 CN CN2009201724113U patent/CN201421325Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102866138A (en) * | 2012-09-13 | 2013-01-09 | 北京瑞利分析仪器有限公司 | Four-quadrant detector-based auxiliary system and method for atomic fluorescence hollow cathode lamp |
| CN109974592A (en) * | 2019-03-28 | 2019-07-05 | 南京工程学院 | A kind of part size detection device and its detection method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100310 Termination date: 20120603 |