CN204536217U - A kind of surface blemish optical detection apparatus - Google Patents
A kind of surface blemish optical detection apparatus Download PDFInfo
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- CN204536217U CN204536217U CN201520220023.3U CN201520220023U CN204536217U CN 204536217 U CN204536217 U CN 204536217U CN 201520220023 U CN201520220023 U CN 201520220023U CN 204536217 U CN204536217 U CN 204536217U
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Abstract
The utility model discloses a kind of surface blemish optical detection apparatus, and described pick-up unit comprises: laser instrument, polarizer, beam expanding lens, the first polarization spectroscope, shearing prism, scan mirror, telecentric scan lens, integrating sphere optical collector, the first photodetector, wave plate, the second polarization spectroscope, the second photodetector; Described laser instrument, polarizer, beam expanding lens set gradually; Described shearing prism is arranged between the first polarization spectroscope and scan mirror; That shears prism is arranged so that incident light is divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle; Described wave plate is arranged between the first polarization spectroscope and the second polarization spectroscope, and the second polarization spectroscope is connected with the second photodetector.The surface blemish optical detection apparatus that the utility model proposes, can improve accuracy of detection and the efficiency of surface blemish.
Description
Technical field
The utility model belongs to technical field of optical detection, relates to a kind of optical detection apparatus, particularly relates to a kind of surface blemish optical detection apparatus.
Background technology
The general Wo Shi prism adopting a particular design at present, and utilize polarisation of light characteristic to realize shear interference.Wo Shi prism has two blocks of birefringece crystals to combine.The faying face of two pieces of crystal is the inclined-planes having certain angle, and the crystallographic axis of two pieces of crystal is mutually vertical.
The laser beam of a branch of linear polarization, after a Wo Shi prism, divide into the light of two bundle polarized orthogonals, o light and e light, and the formation of Wo Shi prism makes o light and e light behind an inclined-plane of prism, due to the difference of refractive index from two different angle outgoing.Now, the joint of two-beam is in the inside of prism.In some applications, the joint of two-beam must some specific position outside prism, now, needs to do some to Wo Shi prism and changes, as two Wo Shi prism.
Two Wo Shi prism is similar by two pieces, but two pieces of Wo Shi prisms that bevel angle is slightly different, add a half-wavelength wave plate (the crystallographic axis angle of wave plate becomes miter angle with the crystallographic axis angle of Wo Shi prism) by centre and form, the size of the angle of the two-beam of such formation is determined by the angle of two pieces of Wo Shi prisms, and second joint can in the outside of prism.
A branch of polarized light can be divided into the light of two bundle polarized orthogonals by above two kinds of prisms, but the angle between the two bundle polarized lights formed is fixing.Fig. 1 is a kind of spectroscopical schematic diagram of shear interference of variable-angle.
The defects detection existing multiple method at present of smooth surface, the optical detecting method that relatively conventional is based on Machine Vision, the feature of this method can detect simultaneously and determine the parameter such as kind, size of defect, but shortcoming is that resolution and detection speed are slower, the usual determination and analysis time at tens seconds to a few minutes, this speed cannot meet the needs of on-line checkingi, reach the crystal face completed a slice is such within 10 seconds to detect, even if adopt hardware and software technology faster, the requirement to detection speed also cannot be reached in a short time.Examine tested smooth surface, find that most of measured surface is the defect that do not have to detect, even if having, its quantity is also little, and nondistinctive detection must be carried out to whole surface based on the detection method of Machine Vision, and thus, no matter measured surface whether defectiveness, detection time is all the same, and the most of the time is used in carry out image acquisition and process to flawless surface.
The smooth surface that laser scanning and scattering detection technique can be 75mm to a diameter in a short period of time detects and determines that (generally can detect the minimum dimension of defect is 1 micron for the particular location of defect, as less flaw size need be detected, detection time can corresponding increase), and rough handling is carried out to defect image, determine point defect or line defect (as cut etc.), the defect map obtained can be transferred to next stage or another detection head on the same stage on equipment carries out quantitative test.
Laser surface scattering has been realized for a long time to the hypersensitivity that the microdefect of smooth surface detects, as early stage optical surface analysis technology (the Optical SurfaceAnalyzer for measuring magnetic store harddisk surface microdefect, OSA) just in the production run of magnetic store hard disk, [list of references 1: " Methodof Inspecting Magnetic Disc and Apparatus Therefor and Process forProducing the Magnetic Disc " is used, US Patent:6, 078, 385, Jun.20, 2000], a equipment for the detection of LED substrate surface of KLA-Tencor company of the current U.S. is also based on this technology, but because traditional design incides on measured surface by after beam of laser line focus in the mode of wide-angle, light beam is confined to the size of hot spot with the interaction zone on surface, general within several millimeter, by mechanically moving the detection that measured surface has come whole surface, although this instrument can carry out determination and analysis to the microdefect of smooth surface, but measuring speed is slower, be not suitable for on-line checkingi.
In view of this, nowadays in the urgent need to designing a kind of new surface blemish optical detection mode, to overcome the above-mentioned defect of existing detection mode.
Utility model content
Technical problem to be solved in the utility model is: provide a kind of surface blemish optical detection apparatus, can improve accuracy of detection and the efficiency of surface blemish.
For solving the problems of the technologies described above, the utility model adopts following technical scheme:
A kind of surface blemish optical detection apparatus, described pick-up unit comprises: laser instrument, polarizer, beam expanding lens, the first adjustment mirror, the second adjustment mirror, the first polarization spectroscope, shearing prism, scan mirror, telecentric scan lens, integrating sphere optical collector, the first photodetector, wave plate, the second polarization spectroscope, the second photodetector;
Described laser instrument, polarizer, beam expanding lens set gradually; Laser beam sends from laser instrument, after polarizer, enters beam expanding lens, as the light source of laser light scattering scanner uni shear interference;
Described first adjustment mirror, the second adjustment mirror are arranged between beam expanding lens and the first polarization spectroscope, and light beam enters the first polarization spectroscope by the first adjustment mirror, the second adjustment mirror after adjusting after beam expanding lens; In the face that light beam polarization direction now and the first polarization spectroscope plane of incidence normal and reflecting surface normal form;
Described shearing prism is arranged between the first polarization spectroscope and scan mirror; Nearly all incident light will be incided by this first polarization spectroscope to be sheared on prism; That shears prism is arranged so that incident light is divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle;
Described telecentric scan lens is arranged between scan mirror and integrating sphere optical collector; Incident beam along a direction rapid scanning, after telecentric scan lens, is formed two at measured surface and converges luminous point, and streak the straight line that a length is L=f2 θ by telecentric scan lens; Here, f is the focal length of telecentric scan lens, and θ is the sweep limit of scan mirror; Two-beam forms two hot spots converged at measured surface, the centre distance of two hot spots is determined by the focal length of telecentric scan lens and the angle of two-beam;
There is a circular or rectangular opening bottom of described integrating sphere optical collector, the diameter of opening or length are slightly larger than the length scanned, the top of integrating sphere optical collector is a thin-and-long opening, at the inside cavities of integrating sphere optical collector, a highly sensitive spot detector is installed, i.e. the first photodetector;
The scattered light signal detection system of above-mentioned integrating sphere optical collector and the first photodetector composition can collect by the light signal of surface imperfection diffuse scattering on ground, for not having defective surface, incident light with surface interaction after, mainly will leave surface with reflected version and Transmissive versions, for opaque tested surface, the main form with reflection is left surface, and the design of integrating sphere make with reflected light form leave surface light substantially do not detected by photodetector, the light left after surface imperfection diffuse scattering is only had just to be detected by photodetector, thus effectively can detect surface imperfection,
Light beam through surface reflection will return by former road, if without any defect in the irradiation area of two hot spots, then two-beam is after surface reflection, the polarization direction light beam consistent with original incident light is synthesized again through shear interference prism, this light beam will enter into laser beam expanding system again along original optical path, almost light does not enter into shear interference detection system, and the photodetector system thus in shear interference light path does not have signal; If being had tiny flaw by the irradiation area of two hot spots, then owing to having certain spacing between two hot spots, when after two-beam synthesis, interference each other can make the position of synthesizing subwave front in light beam change mutually, thus no longer consistent with the polarization direction of original incident light by its polarization direction after shear interference prism, after polarizing prism, some light is entered into the detection system of shear interference through wave plate, the second polarization spectroscope and arrived by the second photoelectric detector of system successively; Because surface ripples, stain, water spots all can to by their light output optical path differences, thus cause the phase change of light beam, and do not have defective surface will not produce such optical path difference, thus this surface imperfection will produce obvious speck under the background of a details in a play not acted out on stage, but told through dialogues.
A kind of surface blemish optical detection apparatus, described pick-up unit comprises: laser instrument, polarizer, the first polarization spectroscope, shearing prism, scan mirror, telecentric scan lens, integrating sphere optical collector, the first photodetector, wave plate, the second polarization spectroscope, the second photodetector;
Described laser instrument, polarizer set gradually; Laser beam sends from laser instrument, after polarizer, as the light source of laser light scattering scanner uni shear interference;
Described shearing prism is arranged between the first polarization spectroscope and scan mirror; Nearly all incident light will be incided by this first polarization spectroscope to be sheared on prism; That shears prism is arranged so that incident light is divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle;
Described wave plate is arranged between the first polarization spectroscope and the second polarization spectroscope, and the second polarization spectroscope is connected with the second photodetector.
As a kind of preferred version of the present utility model, described telecentric scan lens is arranged between scan mirror and integrating sphere optical collector; Incident beam along a direction rapid scanning, after telecentric scan lens, is formed two at measured surface and converges luminous point, and streak the straight line that a length is L=f2 θ by scan mirror; Here, f is the focal length of telecentric scan lens, and θ is the sweep limit of scan mirror; Two-beam forms two hot spots converged at measured surface, the centre distance of two hot spots is determined by the focal length of telecentric scan lens and the angle of two-beam.
As a kind of preferred version of the present utility model, there is a circular or rectangular opening bottom of described integrating sphere optical collector, the diameter of opening or length are slightly larger than the length scanned, the top of integrating sphere optical collector is a thin-and-long opening, at the inside cavities of integrating sphere optical collector, a highly sensitive spot detector is installed, i.e. the first photodetector.
As a kind of preferred version of the present utility model, the scattered light signal detection technique of above-mentioned integrating sphere and photodetector composition collects by the light signal of surface imperfection diffuse scattering effectively, for not having defective surface, incident light with surface interaction after, mainly will leave surface with reflected version and Transmissive versions, for opaque tested surface, the main form with reflection is left surface, and the design of integrating sphere make with reflected light form leave surface light substantially do not detected by photodetector, the light left after surface imperfection diffuse scattering is only had just to be detected by photodetector, thus effectively can detect surface imperfection.
As a kind of preferred version of the present utility model, light beam through surface reflection will return by former road, if without any defect in the irradiation area of two hot spots, then two-beam is after surface reflection, the polarization direction light beam consistent with original incident light is synthesized again through shear interference prism, this light beam will enter into laser beam expanding system again along original optical path, and almost light does not enter into shear interference detection system, and the photodetector system thus in shear interference light path does not have signal;
If being had tiny flaw by the irradiation area of two hot spots, then owing to having certain spacing between two hot spots, when after two-beam synthesis, interference each other can make the position of synthesizing subwave front in light beam change mutually, thus no longer consistent with the polarization direction of original incident light by its polarization direction after shear interference prism, after polarizing prism, some light is entered into the detection system of shear interference through wave plate, the second polarization spectroscope and arrived by the second photoelectric detector of system successively;
Because surface ripples, stain, water spots all can to by their light output optical path differences, thus cause the phase change of light beam, and do not have defective surface will not produce such optical path difference, thus this surface imperfection will produce obvious speck under the background of a details in a play not acted out on stage, but told through dialogues.
As a kind of preferred version of the present utility model, described pick-up unit also comprises the first adjustment mirror, the second adjustment mirror, beam expanding lens; Described first adjustment mirror, the second adjustment mirror are arranged between beam expanding lens and the first polarization spectroscope, and light beam enters the first polarization spectroscope by the first adjustment mirror, the second adjustment mirror after adjusting after beam expanding lens; Light beam polarization direction is now in the face that plane of incidence normal and the reflecting surface normal of the first polarization spectroscope form.
The beneficial effects of the utility model are: the surface blemish optical detection apparatus that the utility model proposes, and can improve accuracy of detection and the efficiency of surface blemish.
Accompanying drawing explanation
Fig. 1 is a kind of spectroscopical schematic diagram of shear interference of variable-angle.
Fig. 2 is the index path of the utility model optical detection apparatus.
Fig. 3 is the structural representation of integrating sphere and photodetector.
Fig. 4 is shear interference prism and index path thereof.
Fig. 5 is the control flow chart of the utility model surface blemish optical detection apparatus.
Embodiment
Preferred embodiment of the present utility model is described in detail below in conjunction with accompanying drawing.
Embodiment one
The utility model is introduced this smooth surface microdefect detector and is adopted telecentric scan lens to carry out the scanning of a direction effects on surface, by moving tested surface in another direction vertical with laser scanning direction, has carried out the scanning to whole tested surface.Current design proposal can carry out continuous sweep to smooth surface, limits by scan mirror deflection angle and telecentric scan lens in the sweep length of laser scanning direction, is not then limiting with its vertical direction.Can effectively detect surface scratch, defect, demoulding etc., replace current manual detection.After adding laser shear interference, also can effectively detect surface ripples, stain, water spots etc.
Refer to Fig. 2, the utility model discloses a kind of surface blemish optical detection apparatus, described pick-up unit comprises: laser instrument 1, polarizer 2, beam expanding lens 3, first adjustment mirror 4, second adjusts mirror 5, first polarization spectroscope 6, shears prism 7, scan mirror 8, telecentric scan lens 9, integrating sphere optical collector 10, first photodetector 11, wave plate 12, second polarization spectroscope 13, second photodetector 14 (if only collimate, then adjust mirror 4, second without the need to beam expanding lens 3, first and adjust mirror 5).
Described laser instrument 1, polarizer 2, beam expanding lens 3 set gradually; Laser beam sends from laser instrument 1, after polarizer 2, enters beam expanding lens 3, as the light source of laser light scattering scanner uni shear interference.
Described first adjustment mirror 4, second adjusts mirror 5 and is arranged between beam expanding lens 3 and the first polarization spectroscope 6, and light beam is adjusted after mirror 5 adjusts by the first adjustment mirror 4, second and enters the first polarization spectroscope 6 after beam expanding lens 3; Light beam polarization direction is now in the face that plane of incidence normal and the reflecting surface normal of the first polarization spectroscope 6 form.
Described shearing prism 7 is arranged between the first polarization spectroscope 6 and scan mirror 8; Nearly all incident light will be incided by this first polarization spectroscope 6 to be sheared on prism 7; Shearing the placement of prism 7 makes incident light be divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle.
Described telecentric scan lens 9 is arranged between scan mirror 8 and integrating sphere optical collector 10; Incident beam along a direction rapid scanning, after telecentric scan lens, is formed two at measured surface and converges luminous point, and streak the straight line that a length is L=f2 θ by scan mirror; Here, f is the focal length of telecentric scan lens, and θ is the sweep limit of scan mirror; Two-beam forms two hot spots converged at measured surface 20, the centre distance of two hot spots is determined by the focal length of telecentric scan lens and the angle of two-beam.
Refer to Fig. 3, there is a circular or rectangular opening 101 bottom of described integrating sphere optical collector 10, the diameter of opening or length are slightly larger than the length scanned, the top of integrating sphere optical collector 10 is a thin-and-long opening 120, at the inside cavities of integrating sphere optical collector 10, a highly sensitive spot detector is installed, i.e. the first photodetector 11.
The scattered light signal detection system of above-mentioned integrating sphere optical collector 10 and the first photodetector 11 composition can collect by the light signal of surface imperfection diffuse scattering on ground, for not having defective surface, incident light with surface interaction after, mainly will leave surface with reflected version and Transmissive versions, for opaque tested surface, the main form with reflection is left surface, and the design of integrating sphere make with reflected light form leave surface light substantially do not detected by photodetector, the light left after surface imperfection diffuse scattering is only had just to be detected by photodetector, thus effectively can detect surface imperfection.
Light beam through surface reflection will return by former road, if without any defect in the irradiation area of two hot spots, then two-beam is after surface reflection, the polarization direction light beam consistent with original incident light is synthesized again through shear interference prism, this light beam will enter into laser beam expanding system again along original optical path, almost light does not enter into by shearing prism 7, first polariscope 6,1/2 wave plate 12, and second polariscope 13 form shear interference detection system, the photodetector system 14 thus in shear interference light path does not have signal; If being had tiny flaw by the irradiation area of two hot spots, then owing to having certain spacing between two hot spots, when after two-beam synthesis, interference each other can make the position of synthesizing subwave front in light beam change mutually, thus no longer consistent with the polarization direction of original incident light by its polarization direction after shear interference prism, after polarizing prism, some light is entered into the detection system 14 of shear interference through wave plate, the second polarization spectroscope and arrived by the second photoelectric detector of system successively; Because surface ripples, stain, water spots all can to by their light output optical path differences, thus cause the phase change of light beam, and do not have defective surface will not produce such optical path difference, thus this surface imperfection will produce obvious speck under the background of a details in a play not acted out on stage, but told through dialogues.
The utility model also discloses a kind of detection method of above-mentioned surface blemish optical detection apparatus, and described detection method comprises the steps:
[step S1] laser beam sends from laser instrument, after polarizer, enters beam expanding lens, as the light source of laser light scattering scanner uni shear interference;
[step S2] light beam enters the first polarization spectroscope by the first adjustment mirror, the second adjustment mirror after adjusting after beam expanding lens; Light beam polarization direction is now in the face that plane of incidence normal and the reflecting surface normal of the first polarization spectroscope form;
[step S3] nearly all incident light will be incided by this first polarization spectroscope to be sheared on prism; That shears prism is arranged so that incident light is divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle;
Incident beam along a direction rapid scanning, after telecentric scan lens, is formed two at measured surface and converges luminous point, and streak the straight line that a length is L=f2 θ by [step S4] scan mirror; Here, f is the focal length of telecentric scan lens, and θ is the sweep limit of scan mirror; Two-beam forms two hot spots converged at measured surface, the centre distance of two hot spots is determined by the focal length of telecentric scan lens and the angle of two-beam;
The scattered light signal detection system of [step S4] integrating sphere optical collector and the first photodetector composition can collect by the light signal of surface imperfection diffuse scattering on ground, for not having defective surface, incident light with surface interaction after, mainly will leave surface with reflected version and Transmissive versions, for opaque tested surface, the main form with reflection is left surface, and the design of integrating sphere make with reflected light form leave surface light substantially do not detected by photodetector, the light left after surface imperfection diffuse scattering is only had just to be detected by photodetector, thus effectively can detect surface imperfection,
[step S5] will return by former road through the light beam of surface reflection, if without any defect in the irradiation area of two hot spots, then two-beam is after surface reflection, the polarization direction light beam consistent with original incident light is synthesized again through shear interference prism, this light beam will enter into laser beam expanding system again along original optical path, almost light does not enter into shear interference detection system, and the photodetector system thus in shear interference light path does not have signal; If being had tiny flaw by the irradiation area of two hot spots, then owing to having certain spacing between two hot spots, when after two-beam synthesis, interference each other can make the position of synthesizing subwave front in light beam change mutually, thus no longer consistent with the polarization direction of original incident light by its polarization direction after shear interference prism, after polarizing prism, some light is entered into the detection system of shear interference through wave plate, the second polarization spectroscope and arrived by the second photoelectric detector of system successively; Because surface ripples, stain, water spots all can to by their light output optical path differences, thus cause the phase change of light beam, and do not have defective surface will not produce such optical path difference, thus this surface imperfection will produce obvious speck under the background of a details in a play not acted out on stage, but told through dialogues.
Embodiment two
In the present embodiment, the laser beam in Fig. 2 sends from laser instrument, after polarizer, enters a parallel beam expand device, as the light source of laser light scattering scanner uni shear interference.After beam expander, light beam enters a polarization spectroscope by after two pieces of reflector alignments, and light beam polarization direction is now in the face that plane of incidence normal and the reflecting surface normal of the first polarization spectroscope form.Nearly all incident light will be incided on a shear interference prism by this polarization spectroscope.The prism of shear interference is placed and is made incident light be divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle (describe in detail and shear component prism see relevant below).
Incident beam along a direction rapid scanning, after telecentric scan lens, is formed two at measured surface and converges luminous point, and streak the straight line that a length is L=f2 θ by scan mirror.Here, f is the focal length of telecentric scan lens, and θ is the sweep limit of scan mirror.Two-beam forms two hot spots converged at measured surface, the centre distance of two hot spots is determined by the focal length of telecentric scan lens and the angle of two-beam.
The integrating sphere of a particular design is have employed in the utility model, there are a circle or rectangular opening (also can be other shapes) in the bottom of this integrating sphere, the diameter of opening or length are slightly larger than the length scanned, the top of integrating sphere optical collector is a thin-and-long opening, at the inside cavities of integrating sphere optical collector, a highly sensitive spot detector is installed; See Fig. 3.
The scattered light signal detection technique of above-mentioned integrating sphere and photodetector composition can collect by the light signal of surface imperfection diffuse scattering effectively, for not having defective surface, incident light with surface interaction after, mainly will leave surface with reflected version and Transmissive versions (measured surface for transparent or semitransparent), for opaque tested surface, the main form with reflection is left surface, and the design of integrating sphere make with reflected light form leave surface light substantially do not detected by photodetector, the light left after surface imperfection diffuse scattering is only had just to be detected by photodetector, thus effectively can detect surface imperfection.
Light beam through surface reflection will return by former road, if without any defect in the irradiation area of two hot spots, then two-beam is after surface reflection, the polarization direction light beam consistent with original incident light is synthesized again through shear interference prism, this light beam will enter into laser beam expanding system again along original optical path, almost light does not enter into shear interference detection system, and the photodetector system thus in shear interference light path does not have signal.If being had tiny flaw by the irradiation area of two hot spots, then owing to having certain spacing between two hot spots, when after two-beam synthesis, interference each other can make the position of synthesizing subwave front in light beam change mutually, thus no longer consistent with the polarization direction of original incident light by its polarization direction after shear interference prism, after polarizing prism, some light entered into the detection system of shear interference and received by the photodetector of system.Because surface ripples, stain, water spots etc. all can to by their light output optical path differences, thus cause the phase change of light beam, and do not have defective surface will not produce such optical path difference, thus this surface imperfection will produce obvious speck under the background of a details in a play not acted out on stage, but told through dialogues, so shear interference is very sensitive to this surface imperfection.The core component of shear interference system is a shear interference prism, and the schematic diagram of this prism is as Fig. 4.
By two bundle same light paths during the effect of the shear interference prism in Fig. 4, but the light of polarized orthogonal is separated, two-beam is made to make a very little angle q from this shear interference prism outgoing, and this two-beam is formed outward at shear interference prism cross, this joint can be made like this to overlap with the back focal plane of follow-up scanning mirror, as shown in Figure 4.
Refer to Fig. 5, synchronous signal acquisition process is as follows: this device has two photodetectors, a photodetector is arranged on integrating sphere, be responsible for the light signal that collection surface scattering produces, another is in shear interference light path, is responsible for collection surface ripple, stain, the isoparametric shear interference signal of water spots.Two signals are respectively by the analog input end inputting a data acquisition card after respective pre-amplification circuit.For obtaining the scan image of a plane, while vibration mirror scanning, this direction, by the motion of one, work with laser line scanning vertical direction, is defined as Y by measured object.Whole scanning process is as follows: system controlling software control Y translation, control vibration mirror scanning simultaneously, at galvanometer from reference position starts scanning, system controlling software is by DAQ card, start the signals collecting of two passages, and by the signal that collects stored in an impact damper of system, and insert a beginning label in the beginning of sweep signal data.After galvanometer completes single pass, in scan-data, insert an end mark, at the same time, Y platform moves with uniform velocity along Y-direction, and the speed of motion is decided by the requirement of scanning accuracy in the Y direction.After scan mirror completes single pass, scan mirror is returned to reference position by control system, starts to scan next time.Repeat this program and can complete two-dimensional scan to a plane.
Embodiment three
A kind of surface blemish optical detection apparatus, described pick-up unit comprises: laser instrument, polarizer, beam expanding lens, the first polarization spectroscope, shearing prism, scan mirror, telecentric scan lens, integrating sphere optical collector, the first photodetector, wave plate, the second polarization spectroscope, the second photodetector.
Described laser instrument, polarizer, beam expanding lens set gradually; Laser beam sends from laser instrument, after polarizer, enters beam expanding lens, as the light source of laser light scattering scanner uni shear interference.Described shearing prism is arranged between the first polarization spectroscope and scan mirror; Nearly all incident light will be incided by this first polarization spectroscope to be sheared on prism; That shears prism is arranged so that incident light is divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle.Described wave plate is arranged between the first polarization spectroscope and the second polarization spectroscope, and the second polarization spectroscope is connected with the second photodetector.
As everyone knows, realize interfering, the light beam that two bundles must be had to be concerned with wholly or in part carries out superposition production capacity and occurs, a branch of in two-beam return light path after reference surface reflects, the so-called reference light of this road light; Another bundle also return light path after the reflection of tested surface, the so-called measurement light of this bundle light.This measures light after the reflection of tested surface, and its wave front carries the topographical information of measured surface due to the reflection of tested surface, and reference light also carries the information of reference surface surface topography after the reflection of reference surface.Usually, the surface topography information of reference surface is known, and like this, when reference light and measurement light are superimposed, the interference fringe of formation just carries the surface topography information of reference surface and tested surface simultaneously.Because the surface topography information of reference surface is known, by process, the topographical information of measured surface can be parsed, thus reach the object of effects on surface topography measurement.
This interferometric measuring means is effective for measurement stationary face, for the situation that measured surface is movement, the movement due to surface inevitably can change the light path of optical path, thus changes result of interference, thus, this device is not suitable for measuring translational surface.The way addressed this problem is shear interference.
In shear interference, two restraint reference light each other, and they are almost overlapping on measured surface, and only have the transversal displacement of very little (relative to a spot diameter), this displacement is commonly referred to shear distance.When two-beam is overlapping on the detector, due to the position of two-beam on measured surface closely, thus after superposition, phasic difference in two-beam wave front is very little, and this phasic difference can make it the difference of generation one 180 degree by the position phase of the prism of change generation shear interference, make the interference after superposing disappear mutually everywhere.If measured surface has a very little deformation, then when two-beam after superposition, due to shear displacemant, has the phasic difference between part surface deformation and reference light to eliminate in picture plane, thus the interference fringe that generation one is bright in picture plane.
In sum, the surface blemish optical detection apparatus that the utility model proposes and method, can improve accuracy of detection and the efficiency of surface blemish.
The utility model have employed the integrating sphere of a particular design as scattered signal collector, the design of this integrating sphere can make incident beam return along former road, and makes from telecentric scan lens outgoing and light that is vertical and measured surface does linear sweep in a direction.
This pick-up unit can add a shear interference system, while scattering scanning, realizes shear interference scanning.
The utility model adopts scan mirror to carry out rapid scanning in a direction, and meanwhile, synchro control Y mobile platform has carried out the scanning to a two dimensional surface.
In addition, the utility model adopts synchro control to realize to the scanning of a plane with to by the laser light scattering of every bit generation in plane and the synchronous acquisition of shear interference signal, to obtain complete laser light scattering and the shear interference image of a tested plane.
Here description of the present utility model and application is illustrative, not wants by scope restriction of the present utility model in the above-described embodiments.Distortion and the change of embodiment disclosed are here possible, are known for the replacement of embodiment those those of ordinary skill in the art and the various parts of equivalence.Those skilled in the art are noted that when not departing from spirit of the present utility model or essential characteristic, the utility model can in other forms, structure, layout, ratio, and to realize with other assembly, material and parts.When not departing from the utility model scope and spirit, can other distortion be carried out here to disclosed embodiment and change.
Claims (5)
1. a surface blemish optical detection apparatus, it is characterized in that, described pick-up unit comprises: laser instrument, polarizer, beam expanding lens, the first adjustment mirror, the second adjustment mirror, the first polarization spectroscope, shearing prism, scan mirror, telecentric scan lens, integrating sphere optical collector, the first photodetector, wave plate, the second polarization spectroscope, the second photodetector;
Described laser instrument, polarizer, beam expanding lens set gradually; Laser beam sends from laser instrument, after polarizer, enters beam expanding lens, as the light source of laser light scattering scanner uni shear interference;
Described first adjustment mirror, the second adjustment mirror are arranged between beam expanding lens and the first polarization spectroscope, and light beam enters the first polarization spectroscope by the first adjustment mirror, the second adjustment mirror after adjusting after beam expanding lens; Light beam polarization direction is now in the face formed with the first polarization spectroscope plane of incidence normal and reflecting surface normal;
Described shearing prism is arranged between the first polarization spectroscope and scan mirror; Nearly all incident light will be incided by this first polarization spectroscope to be sheared on prism; That shears prism is arranged so that incident light is divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle;
Described telecentric scan lens is arranged between scan mirror and integrating sphere optical collector; Incident beam along a direction rapid scanning, after telecentric scan lens, is formed two at measured surface and converges luminous point, and streak the straight line that a length is L=f2 θ by telecentric scan lens; Here, f is the focal length of telecentric scan lens, and θ is the sweep limit of scanning galvanometer; Two-beam forms two hot spots converged at measured surface, the centre distance of two hot spots is determined by the focal length of telecentric scan lens and the angle of two-beam;
There is a circular or rectangular opening bottom of described integrating sphere optical collector, the diameter of opening or length are slightly larger than the length scanned, the top of integrating sphere optical collector is a thin-and-long opening, at the inside cavities of integrating sphere optical collector, a highly sensitive spot detector is installed, i.e. the first photodetector;
The scattered light signal detection system of above-mentioned integrating sphere optical collector and the first photodetector composition can collect by the light signal of surface imperfection diffuse scattering on ground, for not having defective surface, incident light with surface interaction after, mainly will leave surface with reflected version and Transmissive versions, for opaque tested surface, the main form with reflection is left surface, and the design of integrating sphere makes the light leaving surface with reflected light form substantially do not detected by photodetector, the light left after surface imperfection diffuse scattering is only had just to be detected by photodetector.
2. a surface blemish optical detection apparatus, it is characterized in that, described pick-up unit comprises: laser instrument, polarizer, the first polarization spectroscope, shearing prism, scan mirror, telecentric scan lens, optical collector, the first photodetector, wave plate, the second polarization spectroscope;
Described laser instrument, polarizer set gradually; Laser beam sends from laser instrument, after polarizer, as the light source of laser light scattering scanner uni shear interference;
Described shearing prism is arranged between the first polarization spectroscope and scan mirror; Nearly all incident light will be incided by this first polarization spectroscope to be sheared on prism; That shears prism is arranged so that incident light is divided into the equal by force and part of polarized orthogonal of two-beam, and has between two-beam on the back focal plane of telecentric scan lens, to form a very little angle;
Described wave plate is arranged between the first polarization spectroscope and the second polarization spectroscope, and the second polarization spectroscope is connected with the second photodetector.
3. high-sensitivity surface slight flaws optical detection apparatus according to claim 2, is characterized in that:
Described telecentric scan lens is arranged between scan mirror and integrating sphere optical collector; Incident beam along a direction rapid scanning, after telecentric scan lens, is formed two at measured surface and converges luminous point, and streak the straight line that a length is L=f2 θ by telecentric scan lens; Here, f is the focal length of telecentric scan lens, and θ is the scan angle scope of scan mirror; Two-beam forms two hot spots converged at measured surface, the centre distance of two hot spots is determined by the focal length of telecentric scan lens and the angle of two-beam.
4. high-sensitivity surface slight flaws optical detection apparatus according to claim 2, is characterized in that:
There is a circular or rectangular opening bottom of described integrating sphere optical collector, the diameter of opening or length are slightly larger than the length scanned, the top of integrating sphere optical collector is a thin-and-long opening, at the inside cavities of integrating sphere optical collector, a highly sensitive spot detector is installed, i.e. the first photodetector.
5. high-sensitivity surface slight flaws optical detection apparatus according to claim 2, is characterized in that:
Described pick-up unit also comprises the first adjustment mirror, the second adjustment mirror, beam expanding lens; Described first adjustment mirror, the second adjustment mirror are arranged between beam expanding lens and the first polarization spectroscope, and light beam enters the first polarization spectroscope by the first adjustment mirror, the second adjustment mirror after adjusting after beam expanding lens; Light beam polarization direction is now in the face that plane of incidence normal and the reflecting surface normal of the first polarization spectroscope form.
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| CN201520220023.3U CN204536217U (en) | 2015-04-13 | 2015-04-13 | A kind of surface blemish optical detection apparatus |
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| CN201520220023.3U CN204536217U (en) | 2015-04-13 | 2015-04-13 | A kind of surface blemish optical detection apparatus |
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| CN105572138A (en) * | 2016-02-24 | 2016-05-11 | 唐山英莱科技有限公司 | High-light-reflection butt weld detecting method and device based on polarization detection |
| CN105911072A (en) * | 2016-06-08 | 2016-08-31 | 浙江工业大学 | Optical rapid detection device for minor flaws on surfaces of spheres |
| CN106153626A (en) * | 2015-04-13 | 2016-11-23 | 无锡迈福光学科技有限公司 | A kind of surface blemish optical detection apparatus and detection method thereof |
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| CN110220919A (en) * | 2019-06-19 | 2019-09-10 | 华中科技大学 | A kind of multichannel scattering light collecting device for surface defects detection |
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| CN106153626A (en) * | 2015-04-13 | 2016-11-23 | 无锡迈福光学科技有限公司 | A kind of surface blemish optical detection apparatus and detection method thereof |
| CN106153626B (en) * | 2015-04-13 | 2019-02-22 | 无锡迈福光学科技有限公司 | A kind of surface blemish optical detection apparatus and its detection method |
| CN105572138A (en) * | 2016-02-24 | 2016-05-11 | 唐山英莱科技有限公司 | High-light-reflection butt weld detecting method and device based on polarization detection |
| CN105911072A (en) * | 2016-06-08 | 2016-08-31 | 浙江工业大学 | Optical rapid detection device for minor flaws on surfaces of spheres |
| CN105911072B (en) * | 2016-06-08 | 2018-09-07 | 浙江工业大学 | A kind of optics device for fast detecting of spherome surface slight flaws |
| CN108072613A (en) * | 2016-11-11 | 2018-05-25 | 台湾积体电路制造股份有限公司 | Optical detection apparatus and its detection method |
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| CN110220919A (en) * | 2019-06-19 | 2019-09-10 | 华中科技大学 | A kind of multichannel scattering light collecting device for surface defects detection |
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