CN101074868A - Method and apparatus for inspection automatically focusing non-spherical surface - Google Patents
Method and apparatus for inspection automatically focusing non-spherical surface Download PDFInfo
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- CN101074868A CN101074868A CN 200710009115 CN200710009115A CN101074868A CN 101074868 A CN101074868 A CN 101074868A CN 200710009115 CN200710009115 CN 200710009115 CN 200710009115 A CN200710009115 A CN 200710009115A CN 101074868 A CN101074868 A CN 101074868A
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Abstract
An automatic-focusing method of aspheric surface detection includes using focal point of eye lens as original point of coordinate to confirm coordinate of output optical axis on laser and eye lens to optical axis of objective lens, calculating out position A and position B of light spot on photoelectric detector, calculating out distance D of reflection point relatively to focal point of eye lens after focusing head is translated, carrying out rough and fine regulation and fetching total displacement of grating rule to finalize measurement after focusing is succeeded. The device used for realizing said method is also disclosed.
Description
Technical field
The present invention relates to a kind of detection of non-spherical element, the contactless automatic focusing of employing that especially relates to a kind of closed-loop control detects the method and the device thereof on aspherical optical element surface.
Background technology
Aspherical optical element obtains more and more widely application at civil areas such as military domain such as national defence aviation and electronics and IT products, and detection technique is to improve the main bottleneck of product manufacturing accuracy always.
(Qiao Yujing such as Qiao Yujing, Lv Ning. aspheric surface and non-spherical measuring technology, Harbin University of Commerce's journal, 2005,21 (3): 357-361) introduced existing several aspheric surface detection method, but these methods precision and simple and easy to do on can't satisfy the aspheric detection requirement of high precision.
(beam Cuipings such as beam Cuiping, Li Qingan, Qiao Yanfeng, Zhu Wei. the method for brief analysis optical system automatic focusing, electric light and control, 2006,13 (6): 93-96) having reported that a kind of technology of auto is an Autofocus Technology, is the new technique that a kind of precision is higher, be widely used in aspects such as computer vision and imaging.
Summary of the invention
The objective of the invention is defective at present aspheric surface detection method existence, for breaking through the bottleneck that the high precision aspheric surface detects, provide a kind of simple in structure, practical, and can not damage the detected element surface, can detect the aspheric surface of various different transparencies, accuracy of detection can reach nano level non-spherical surface and detect automatic focusing method and device thereof.
Non-spherical surface of the present invention detects automatic focusing mechanism and is provided with focusing head, I/V amplifier, single-chip microcomputer, light-coupled isolation device, servoamplifier, servomotor, grating chi and computing machine.Wherein the focusing head is provided with laser instrument, catoptron, eyepiece, object lens, photodetector and cylindrical shell; Catoptron, eyepiece, object lens and photodetector are set in turn in the cylindrical shell, and laser instrument is located at cylinder inboard wall, and the optical axis coincidence of object lens, eyepiece is defined as common optical axis, and the geometric center of photodetector is on common optical axis; The output optical axis of laser instrument is vertical with common optical axis, and catoptron is positioned on the laser instrument output optical axis, and the optical axis of mirror reflects light is parallel with common optical axis.Cylindrical shell and grating chi connect as one.The output termination I/V amplifier input terminal of photodetector, the output terminal of I/V amplifier connects the I/O analog quantity input port of single-chip microcomputer, the port of single-chip microcomputer output square wave connects the light-coupled isolation device, light-coupled isolation device output terminal connects the input end of servoamplifier, the output servo motor termination of servoamplifier, servo motor shaft is connected as a single entity by the cylindrical shell of leading screw and focusing head.The communication module of single-chip microcomputer connects serial ports of computers by RS232.Measured workpiece is located on the focus of eyepiece.
Non-spherical surface of the present invention detects automatic focusing method and may further comprise the steps:
1) focus with eyepiece is decided to be true origin, and laser instrument output optical axis direction is a directions X, and the common optical axis direction from the eyepiece to object lens is the Z direction, and the Y direction is determined according to Cartesian coordinates.
2) measured workpiece is arranged on the eyepiece focus.
3) single-chip microcomputer record I/O mouth analog input amount V0 calculates the position P0 of hot spot on photodetector.
4) focusing head translation one slight distance L1 on measuring route direction default on the XY plane, single-chip microcomputer record I/O mouth analog input amount V1, calculate the position P1 of hot spot on photodetector, according to P0 and P1, single-chip microcomputer calculates the reflection spot of workpiece after the focusing translation with respect to the distance D of eyepiece focus.
5) coarse adjustment focusing, single-chip microcomputer output control square wave, drive motor makes the focusing head along Z direction displacement D.
6) single-chip microcomputer detects I/O mouth analog quantity input value, calculate hot spot on photodetector position P2 and with P0 relatively, if identical or deviation within the specification error scope, is then focused successfully automatically; If deviation is outside the specification error scope, then single-chip microcomputer output square wave carries out fine focus, single-chip microcomputer detects I/O analog input value once more after the accurate adjustment, calculate the position P3 of hot spot on photodetector, and with P0 relatively, if deviation outside the specification error scope, then repeats smart focusing step, until focusing successfully.
7) after focusing successfully, read the total displacement of grating chi, and send computing machine to.
8) according to default measuring route repeating step 4～7, until the non-spherical surface that measures whole measured workpiece.
9), go out the non-spherical surface curve of measured workpiece by computer fitting according to measuring route and optical grating ruler measurement value.
The value of L1 is relevant with measuring accuracy, and L1 is more little, and the dot matrix that records is close more, measures accurately more, and the actual value of L1 can generally be chosen as 0.0001～1mm according to the accuracy selection of equipment.
Compare with existing aspheric surface detection method, the present invention has following outstanding advantage:
1. non-contact detection can not damaged measured piece.
2. measuring accuracy height.Because of adopting pattern displacement measuring technique and Closed loop Control, can obtain nano level surperficial accuracy of detection.
3. simple to operate.As long as the tested relatively aspheric surface single pass of focusing mechanism can be obtained non-spherical surface face shape.Measuring process realizes automatically, need not the tested aspheric surface of manual adjustment.
4. cost is low.It is simple and reliable to form the required device of this system.
This shows, utilize the present invention to detect the high precision aspheric surface, can effectively solve the problem that the conventional sense method exists, have very big researching value and feasibility.
Description of drawings
Fig. 1 is the automatic focusing method and the device synoptic diagram of the embodiment of the invention.
Fig. 2 is the focusing header structure synoptic diagram of the embodiment of the invention.
Fig. 3 is the synoptic diagram of the I/V amplifier of the embodiment of the invention.
Embodiment
Following examples will the present invention is further illustrated in conjunction with the accompanying drawings.
Referring to Fig. 1 and 2, the non-spherical surface of the embodiment of the invention detects automatic focusing mechanism and is provided with focusing 2, I/V amplifier 3, single-chip microcomputer 4, light-coupled isolation device 5, servoamplifier 6, servomotor 7, grating chi 8 and computing machine 9.Focusing 2 is provided with cylindrical shell 11, laser instrument 12, catoptron 13, eyepiece 14, object lens 15 and photodetector 16, and cylindrical shell 11 and grating chi 8 connect and be one, and are connected by the output shaft of leading screw with servomotor 7.
When the aspheric surface measured workpiece 1 on being located at work stage 10 places the focus of eyepiece 14 of focusing head, photodetector 16 output currents of focusing head, handle the analog quantity input I/O pin that enters single-chip microcomputer 4 by I/V amplifier 3, single-chip microcomputer 4 is calculated the position P of laser facula on the photodetector 16 and is preserved.
When focusing head during according to the detection path offset distance L 1 set, the point of reflector laser changes on the measured workpiece 1, reflection spot is not positioned at the focus of eyepiece 14, laser direction after the reflection changes, the laser beam that enters object lens 15 changes, the corresponding change of facula position on the photodetector 16 changes four road output currents of photodetector 16, and the analog signals that enters single-chip microcomputer 4 also changes.According to the calculating of the twice measured value side-play amount D of measured workpiece 1 offset eyepiece 14 focuses more as can be known.Single-chip microcomputer 4 sends corresponding square-wave signal according to side-play amount D, enters servoamplifier 6 after isolating through light-coupled isolation device 5, drives servomotor 7, and focusing 2 is slightly focused along Z direction move distance D.After thick focusing is finished, detect the analog input amount of single-chip microcomputer 4 again, calculate facula position and with position P relatively, if bias free or deviation then focus successfully, read the focusing displacement on the focusing Z direction that grating chi 8 records within preset range; If deviation is arranged, then carry out the essence focusing according to deviation output square wave drive servomotor 7, essence detects the analog input amount of single-chip microcomputer 4 again to defocused, if deviation is arranged, then repeats smart focusing step, until focusing successfully, reads the total displacement of grating chi 8.Focusing displacement on the Z direction that grating chi 8 is measured sends computing machine 9 to.Computing machine 9 is according to the tested non-spherical surface curve of the measured value match of measuring route and grating chi 8.For the ease of debug system, single-chip microcomputer 4 also can be received the serial ports of computing machine 9 by MAX232, shows detected state in real time.
In Fig. 2, the focusing head is provided with cylindrical shell 11, laser instrument 12, catoptron 13, eyepiece 14, object lens 15 and photodetector 16, and cylindrical shell 11 and grating chi 8 connect and be one, and are connected by the output shaft of leading screw with motor 7.The optical axis coincidence of eyepiece 14 and object lens 15 is defined as common optical axis, and the geometric center of photodetector 16 is also on common optical axis.The laser that laser instrument 12 sends is parallel to common optical axis through the light beam behind the catoptron 13 17 and incides on the eyepiece 14, converges at measured workpiece 1 surface; After measured workpiece 1 surface reflection, light beam incides eyepiece 14 again, and outgoing beam 18 also is parallel to optical axis; Outgoing beam 18 converges on the photodetector 16 through object lens 15.When measured workpiece 1 is positioned at different positions and angle, the different electric current of photodetector 16 outputs.Light beam 17 and 18 constitutes eccentric pencil, and the size influence focusing precision of offset s (being the distance between light beam 17 and 18) should be adjusted to the best according to actual measurement.
Referring to Fig. 3, the leading-out terminal of focusing 2 is the four tunnel little electric currents and the electrode common port of photodetector, the electrode common end grounding, and the processing mode of four road photocurrents is identical, and Fig. 3 is the wiring of the I/V amplifier 3 of wherein one road photocurrent.With reference to connection be: A1 selects precision amplifier LF411 for use, and little current conversion is a magnitude of voltage, connects amplifier μ A741 again, makes magnitude of voltage be converted to the discernible voltage of I/O pin of single-chip microcomputer 4.Wherein capacitor C 1 is 100P, and resistance R 1, R2, R3 and R4 adopt suitable resistance value according to the output photocurrent of PSD, and R4 can be designed to variohm, and JP is a wire jumper, and optional energising resistance R3 or R4 adapt to the photocurrent output of different range, and GND is a ground connection; If R3 is connected into circuit, the input/output relation of this circuit is:
Claims (3)
1. non-spherical surface detects automatic focusing mechanism, it is characterized in that being provided with focusing head, I/V amplifier, single-chip microcomputer, light-coupled isolation device, servoamplifier, servomotor, grating chi and computing machine; The focusing head is provided with laser instrument, catoptron, eyepiece, object lens, photodetector and cylindrical shell; Catoptron, eyepiece, object lens and photodetector are set in turn in the cylindrical shell, laser instrument is located at cylinder inboard wall, the common optical axis of object lens, eyepiece overlaps, the geometric center of photodetector is on common optical axis, the output optical axis of laser instrument is vertical with common optical axis, catoptron is positioned on the laser instrument output optical axis, and the optical axis of mirror reflects light is parallel with common optical axis; Cylindrical shell and grating chi connect as one, the output termination I/V amplifier input terminal of photodetector, the output terminal of I/V amplifier connects the I/O analog quantity input port of single-chip microcomputer, the port of single-chip microcomputer output square wave connects the light-coupled isolation device, light-coupled isolation device output terminal connects the input end of servoamplifier, the output servo motor termination of servoamplifier, servo motor shaft is connected as a single entity by the cylindrical shell of leading screw and focusing head; The communication module of single-chip microcomputer connects serial ports of computers by RS232.
2. non-spherical surface detects automatic focusing method, it is characterized in that may further comprise the steps:
1) focus with eyepiece is decided to be true origin, and laser instrument output optical axis direction is a directions X, and the common optical axis direction from the eyepiece to object lens is the Z direction, and the Y direction is determined according to Cartesian coordinates;
2) measured workpiece is arranged on the eyepiece focus;
3) single-chip microcomputer record I/O mouth analog input amount V0 calculates the position P0 of hot spot on photodetector;
4) focusing head translation distance L1 on measuring route direction default on the XY plane, single-chip microcomputer record I/O mouth analog input amount V1, calculate the position P1 of hot spot on photodetector, according to P0 and P1, single-chip microcomputer calculates the reflection spot of workpiece after the focusing translation with respect to the distance D of eyepiece focus;
5) coarse adjustment focusing, single-chip microcomputer output control square wave, drive motor makes the focusing head along Z direction displacement D;
6) single-chip microcomputer detects I/O mouth analog quantity input value, calculate hot spot on photodetector position P2 and with P0 relatively, if identical or deviation within the specification error scope, is then focused successfully automatically; If deviation is outside the specification error scope, then single-chip microcomputer output square wave carries out fine focus, single-chip microcomputer detects I/O analog input value once more after the accurate adjustment, calculate the position P3 of hot spot on photodetector, and with P0 relatively, if deviation outside the specification error scope, then repeats smart focusing step, until focusing successfully;
7) after focusing successfully, read the total displacement of grating chi, and send computing machine to;
8) according to default measuring route repeating step 4～7, until the non-spherical surface that measures whole measured workpiece;
9), go out the non-spherical surface curve of measured workpiece by computer fitting according to measuring route and optical grating ruler measurement value.
3. non-spherical surface as claimed in claim 2 detects automatic focusing method, it is characterized in that described L1 is 0.0001～1mm.
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| CNB2007100091157A CN100501316C (en) | 2007-06-18 | 2007-06-18 | Method and apparatus for automatically focusing of non-spherical surface inspection |
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| CNB2007100091157A CN100501316C (en) | 2007-06-18 | 2007-06-18 | Method and apparatus for automatically focusing of non-spherical surface inspection |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101655356B (en) * | 2009-09-08 | 2010-12-01 | 厦门大学 | Graduation device for detecting surface shape of aspheric optical element |
| CN102183214A (en) * | 2011-03-03 | 2011-09-14 | 中国科学院光电技术研究所 | Method for optically detecting large-aperture aspherical mirror structure |
| CN103212823A (en) * | 2012-01-19 | 2013-07-24 | 昆山思拓机器有限公司 | Focus seeking method for photoelectric focus seeking device |
| CN103217098A (en) * | 2012-01-19 | 2013-07-24 | 昆山思拓机器有限公司 | Focus finding method for multi-spectral photoelectrical focus finding device |
| CN106334872A (en) * | 2016-08-30 | 2017-01-18 | 淮阴工学院 | Automatic focusing and real-time fine adjustment method for laser end surface texture machine |
| CN109141825A (en) * | 2018-09-13 | 2019-01-04 | 西华大学 | Subwavelength optics image device focal length measuring equipment and its measurement method |
| CN112799263A (en) * | 2020-12-31 | 2021-05-14 | 苏州科韵激光科技有限公司 | Laser-based objective lens focusing method and system |
| CN112834170A (en) * | 2021-01-07 | 2021-05-25 | 高安天孚光电技术有限公司 | Long-focus non-contact test jumper device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6002483A (en) * | 1998-03-16 | 1999-12-14 | National Research Council Of Canada | Non-contact interference optical system for measuring the length of a moving surface with a large N.A. collector optical system |
| US6312373B1 (en) * | 1998-09-22 | 2001-11-06 | Nikon Corporation | Method of manufacturing an optical system |
| CN100419378C (en) * | 2005-06-23 | 2008-09-17 | 麦克奥迪实业集团有限公司 | Apparatus and method for testing aspherical surface shape error of optical lens |
| CN100437026C (en) * | 2006-07-20 | 2008-11-26 | 厦门大学 | Body surface three-dimensional topographic information measuring device |
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- 2007-06-18 CN CNB2007100091157A patent/CN100501316C/en not_active Expired - Fee Related
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101655356B (en) * | 2009-09-08 | 2010-12-01 | 厦门大学 | Graduation device for detecting surface shape of aspheric optical element |
| CN102183214A (en) * | 2011-03-03 | 2011-09-14 | 中国科学院光电技术研究所 | Method for optically detecting large-aperture aspherical mirror structure |
| CN102183214B (en) * | 2011-03-03 | 2014-03-26 | 中国科学院光电技术研究所 | Method for optically detecting large-aperture aspherical mirror structure |
| CN103217098B (en) * | 2012-01-19 | 2017-05-03 | 昆山思拓机器有限公司 | Focus finding method for multi-spectral photoelectrical focus finding device |
| CN103212823A (en) * | 2012-01-19 | 2013-07-24 | 昆山思拓机器有限公司 | Focus seeking method for photoelectric focus seeking device |
| CN103217098A (en) * | 2012-01-19 | 2013-07-24 | 昆山思拓机器有限公司 | Focus finding method for multi-spectral photoelectrical focus finding device |
| CN103212823B (en) * | 2012-01-19 | 2016-08-31 | 昆山思拓机器有限公司 | The focus searching method of Photoelectric Jiao's device |
| CN106334872A (en) * | 2016-08-30 | 2017-01-18 | 淮阴工学院 | Automatic focusing and real-time fine adjustment method for laser end surface texture machine |
| CN106334872B (en) * | 2016-08-30 | 2017-12-01 | 淮阴工学院 | The auto-focusing and real-time method for trimming of laser edge texture machine |
| CN109141825A (en) * | 2018-09-13 | 2019-01-04 | 西华大学 | Subwavelength optics image device focal length measuring equipment and its measurement method |
| CN112799263A (en) * | 2020-12-31 | 2021-05-14 | 苏州科韵激光科技有限公司 | Laser-based objective lens focusing method and system |
| CN112834170A (en) * | 2021-01-07 | 2021-05-25 | 高安天孚光电技术有限公司 | Long-focus non-contact test jumper device |
| CN112834170B (en) * | 2021-01-07 | 2022-12-30 | 高安天孚光电技术有限公司 | Long-focus non-contact test jumper device |
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