CN106959293A - The system and method for defect on reflective surface is detected by vision system - Google Patents

Abstract

The present invention relates to a kind of use knife edge technology come system and method that the reflective planar defect on reflective surface is detected and is imaged, wherein, camera aperture or external device (ED), which are provided in light path, forms physics knife edge structure, the physics knife edge structure advantageously covers the reflection light from the illuminated reflective surface with predetermined slope value, and make it that the light deflected with different slopes reaches vision system camera sensor.The wide majority reflected from the flat on surface is stopped by knife edge.During the wide majority reflected from the ramp portion of defect is reflected to entrance hole diameter.Illumination beam it is angled relative to the optical axis of camera with the surface that provides and be examined into proper angle incidence angle.The surface can with it is static or relative to camera move.

Description

The system and method for defect on reflective surface is detected by vision system

The cross reference of related application

This application claims the rights and interests of following application documents：It is entitled " by vision system in what is submitted on November 13rd, 2015 System and method (the SYSTEM AND METHOD FOR DETECTING DEFECTS ON A of defect on system detection reflective surface SPECULAR SURFACE WITH A VISION SYSTEM) ", the Serial No. No.62/255,360 interim Shen in the pending U.S. Please；The title submitted on December 31st, 2015 " detects the system and method (SYSTEM of defect on reflective surface by vision system AND METHOD FOR DETECTING DEFECTS ON A SPECULAR SURFACE WITH A VISION SYSTEM) ", Serial No. No.62/274,094 U.S. Provisional Application；And submitted on October 5, in 2016 it is entitled " system and method (the SYSTEM AND METHOD FOR DETECTING of defect on reflective surface are detected by vision system DEFECTS ON A SPECULAR SURFACE WITH A VISION SYSTEM) ", Serial No. No.62/404,431 U.S. Provisional Application, the teaching of above-mentioned application is expressly incorporated herein by reference.

Technical field

The present invention relates to the NI Vision Builder for Automated Inspection on the surface for checking object, and more particularly, to for checking The vision system of reflective surface.

Background technology

NI Vision Builder for Automated Inspection, also referred to herein " vision system ", for performing various tasks in a manufacturing environment.It is logical Often, vision system is made up of one or more cameras with imaging sensor (or " imager "), the imaging sensor The gray scale or coloured image of scene are gathered, the scene includes object to be produced.The image of object can be analyzed with to User provides data/information and associated production technology.Data produced by image are generally by can be with special one Or more vision system in vision system processor, or all-purpose computer is (for example, PC, laptop computer, panel computer Or smart mobile phone) in instantiation one or more software applications in a part analyzed and handled.Vision Some type of task performed by system can include, to object and static or movement surface (means of transport), such as transmitting Surface on machine or mobile station is checked.

For vision system, the object of reflective mirror polish is carried out surface inspection have confirmed it is challenging.It is logical Often, the reflection from surface can because enter a large amount of reflected lights of camera cause defect and surface blemish (for example, pitting/trench and/ Or projection/hill) colour fading that seems (washed out), the defect and surface blemish this represent table of the zonule relative to surrounding There is small difference in the gradient in face.A kind of method of surface defect for trying to find out on reflective surface is by using dark field light According to, wherein, the illumination light being projected on object is not collected at object lens.This is used to make the arbitrary surfaces defect of scattering light It is highlighted.However, this technology in following environment for being installed and being limited using existing, i.e. including object and photomoduel Between relative movement environment.

The content of the invention

Come instant invention overcomes the shortcoming of prior art there is provided a kind of use knife edge technology to the reflective surface on reflective surface The system and method that defect is detected and is imaged, wherein, camera aperture or external device (ED) are provided in formation in light path Knife edge structure is managed, the physics knife edge structure advantageously covers the reflection from the illuminated reflective surface with predetermined slope value Light, and make it that the light deflected with different slopes reaches vision system camera sensor.In one embodiment, illuminate Device is by optically focused in order to which the big region in the region on the surface being examined from the ratio of luminaire comes out and converges to the region on surface On.Light by (reflective surface) otherwise region is reflected and continues to converge on the spot near the entrance hole diameter of camera, or phase The spot on aperture diaphragm (for example, adjustable aperture) on the inside of machine.At any position, reflected from the flat on surface Wide most stopped by knife edge or aperture diaphragm.On the contrary, the wide majority reflected from the ramp portion of defect is reflected Into entrance hole diameter.Illumination beam it is angled relative to the optical axis of camera with the surface that provides and be examined into proper angle Incidence angle.Schematically, luminaire can include linear polarizer, and polarised light is sent to the table of object by the linear polarizer Face.Object can be multilayer, and can include such as polarization layer.Polarization light reflects from surface and enters camera sensing The cross-polarization piece that device/camera optics go out.Schematically, surface can be static and can be by 2D sensor arrays Gathered, or surface is moved relative to camera, the camera can be defined with the linescan cameras of line scan sensor.

Be used in one exemplary embodiment to the system of the defect imaging on the reflective surface of object there is provided a kind of and Method.Surface is imaged by vision system camera, and the vision system camera has imaging sensor and optics and limited Optical axis is determined.Illuminate device assembly, its with the not parallel predetermined angle of the optical axis by the light beam projecting of construction to the surface.Knife Edge element is associated with optics, and the knife edge element changeably stops a part for the maximum field of view of optics.Knife edge member Part and predetermined angular be each arranged to so that：The light for being transmitted into sensor from optics generally penetrates the defect on surface The slope hill and trench or waveform and ripple of feature, and reflected light around the defect characteristic of slope hindered by knife edge element Gear.Schematically, knife edge element includes the variable aperture in optical element, and predetermined angular becomes with the surface from flat surfaces The slope of shape is associated.In embodiment, sensor is 2D sensors and object is static relative to camera.Alternately, pass Sensor limits linescan cameras device and object and moved relative to camera, and light fixture is by illuminating line.Project to surface It is upper to use row illuminating line so that checking moving parts by 2D sensors and checking more much bigger than the region that single image is covered Part.In embodiment, in addition to visible light, luminaire generally defines infrared or near infrared wavelength region, and Object can limit the layer including ARC and/or polarization layer, in this case, and luminaire can be polarized and light Learning device includes polarizing filter.By non-limiting example mode, object can be AMOLED display screens, and polarization layer is 1/4 λ delayers and polarizing filter are defined to orthogonal polarizing filters.Luminaire can be included for the inclined of polarization illumination light Shake piece, and optics includes polarizing filter.Light source can be defined to convergent pencil of rays, and the convergent pencil of rays is attached towards knife edge structure Near a little restrains.The external structure that knife edge structure can be defined to be located in the light path before optics (is located at optics device Between part and object).Schematically, ray cast is placed through the beam splitting on the optical axis of vision system camera by illumination device assembly Device so that：The off-axis illumination for coming from illumination device assembly is projected to body surface with optical axis coincidence.In another embodiment In, illumination device assembly defines each by ray cast to each beam splitter, Mei Gefen in multiple light sources, multiple light sources Beam device is located on the optical axis of vision system camera so that：The off-axis illumination for coming from illumination device assembly is projected by each beam splitter To the body surface with the optical axis coincidence.

Schematically, knife edge element can be defined to the barrier structure in the optics on optical axis.The blocking junction Structure is arranged in the mask member adjacent with before optics.The barrier structure can be configured to optionally for The associated scattered light of feature is strengthened or suppressed.Barrier structure can be limited to be extended through optics along prolonging direction Line, and can have it is relevant with the size of the focus illumination spot on optics, along the width for crossing prolonging direction Degree.Direction of elongate can be limited by the orientation of feature.Mask member includes impermeable around on each opposite side of line Area pellucida domain, has linear aperture between zone of opacity online.Barrier structure includes disk, and the center of disk is approximately at light On axle and with the diameter relevant with the size of one or more of feature.Loop configuration can surround disk, and can be with Limit the annular aperture between disk and the inner circumferential of annular region.Annular region can be configured to suppress scattered light.Schematically, Mask member defines one of at least following part：Buckle type or screw-on lens cover, the top before optics Applique, and the changeable mode photoelectricity mechanism on optics.In embodiment, device can include be configured to Optics combines the first polarizer and is configured to illuminating the second polarizer that device assembly is combined.

Brief description of the drawings

Following explanation is done to the present invention with reference to accompanying drawing, wherein：

Fig. 1 is the diagram of the exemplary vision system with the camera for including 2D pel arrays, and the camera, which is used to gather, to be had The image of defective exemplary stationary body surface, the exemplary vision system includes luminaire and the control of diaphragm, the aperture The areal deformation defect characteristic being configured on the reflective surface to stationary object surface is controlled to parse；

Fig. 2 is the diagram of the exemplary vision system with the camera for including row scanning (1D) pel array, and the camera is used Image in the defective exemplary mobile object surface of collection tool, the exemplary vision system includes luminaire and aperture control System, the areal deformation defect characteristic that the control of diaphragm is configured on the reflective surface to mobile object surface is parsed；

Fig. 3 is the diagram of the application for the knife-edge effect that areal deformation defect characteristic is parsed according to Fig. 1 or Fig. 2 device；

Fig. 4 is the diagram of the vision system arrangement in Fig. 2, and the vision system is arranged to being configurable to include exemplary polarization The multilayer of layer, form are scanned for the exemplary objects of AMOLED display screens, wherein, object includes being located at above-mentioned layer extremely Hill and trench defect characteristic in few one layer；

Fig. 5 is the side view of vision system arrangement in Fig. 4 and exemplary scanned object, and it illustrates the light of illumination light Road and the light on hill defect characteristic reflected gathered；

Fig. 6 is the side view of vision system arrangement in Fig. 4 and exemplary scanned object, and it illustrates the light of illumination light Road and the light on trench defect characteristic reflected gathered；

Fig. 7 be according to the vision system of exemplary embodiment arrange side view, it illustrates with camera and optics The use of associated knife edge structure；

Fig. 8 is the side view according to the vision system of another embodiment arrangement and exemplary scanned object, and it shows Multiple light sources and associated knife edge component；

Fig. 9 and Figure 10 are the diagrams of the vision system of the description operation according to Fig. 1, and the vision system includes providing and camera Optical axis coincidence off-axis illumination light beam splitter, the beam splitter has used a luminaire, and camera has used two illuminations Device；

Figure 11 represents the image on the exemplary objects surface with visual defects feature, and these visual defects features are used It is shown according to the vision system of the embodiments herein in the form of echo around surface；

Figure 12 is the ripple on the reflective surface according to the use off-axis illumination and knife edge device of embodiment to determine object The flow chart of process；

Figure 13 to Figure 15 be respectively illustrate the combination of smooth surface characteristics and corrugated surface feature, corrugated surface feature, And the exemplary histograms of the image intensity of the response of smooth surface characteristics；

Figure 16 is exemplary with the row of scanning of a surface, luminaire and imaging sensor for irradiating according to embodiment Optical devices；

Figure 17 is the perspective view of Figure 16 diagram；

Figure 18 is illustrated according to the exemplary vision system camera and luminaire of illustrative examples, wherein, use and covered The knife edge element of modular form, the knife edge element include positioned at camera optical module before or within fixation or changeable filter member Part；

Figure 19 is the exemplary camera for combination Figure 18 to limit the exemplary nontransparent Central Line in linear aperture The front view of mask；

Figure 20 is the front view for limiting the mask of the exemplary disk element of the centre positioned at optical module；

Figure 21 to 25 is the front view of exemplary nontransparent disc elements and outer annular element respectively, nontransparent disc elements and Outer annular element is separated by annular aperture therebetween, and each element defines predetermined diameter；

Figure 26 is the exemplary objects (example of vision system camera with mask in Figure 18 and illuminator device imaging Such as, touch screen surface) image, it illustrates the corrugated surface details in the exemplary objects；

Figure 27 is Figure 18 vision camera system and illuminator device imaging, exemplary objects in Figure 26 figure Picture, which further illustrates details in touch screen surface (for example, sensor array)；And

Figure 28 is Figure 18 vision camera system and illuminator device imaging, exemplary objects in Figure 26 figure Picture, it illustrates the details of the high precision of the sensor array in Figure 27.

Embodiment

Fig. 1 is the diagram according to the exemplary vision system of illustrative examples arrangement 100, wherein, scene includes relative In the reflective object 110 of the static setting of static vision system camera 120.In this embodiment, vision system camera 120 includes two (2D) imaging sensor S is tieed up, in (such as) rectangular arrangement, two-dimensional image sensor S includes N × M pel arrays.Camera includes Optical package OC, optical package OC can include any acceptable lens subassembly (for example, with c-type objective holder, F types The lens of objective holder or M12 type pedestals).In this embodiment, lens include manually or automatically pore size control --- for example, variable Aperture, wherein, suitable aperture setting 124 can be input to manually or automatically aperture control by user or other outside effectors In system (as described further below).Sensor S and optical package OC collectively define optical axis OA, and the optical axis leads to Often perpendicular to the broad sense surface plane of object 110.Arrangement 100 include luminaire 130, the luminaire 130 by light (for example, By optics OI) collimated light beam 132 projected on surface 110.In one embodiment, light beam 132 is adjusted to very big Part maintains on object and avoids extending to remaining scene.Light beam 132 is positioned in wide with the reflective surface of object 110 Adopted plane angulation A.The angle and plane normal N and out of plumb (being usually acute angle).Normal N is typically parallel to camera optical axis OA.

As shown, the surface of object 110 includes defect characteristic 140, and the defect characteristic 140 can be limited downwards The trench (also referred to as " cheating ") gradually opened or the hill (also referred to as " projection ") raised up, it can use arrangement described below Effectively it is imaged with technology.In one exemplary embodiment, the picture number of the scene being illuminated and object 110 is come from Vision system processor 150 is transferred into according to 140.Processor 150 can directly be integrated into one or more phase units In part, or it can be located at as depicted on separate computing device 160, the stand-alone computer device 160 has suitable User interface (for example, mouse 162, keyboard 164) and display function (screen and/or touch-screen 166).Computing device 160 can With including server, PC, laptop computer, smart mobile phone or special processor, with the other kinds of of relational storage Processor, network equipment, data storage etc., this should be clear for a person skilled in the art.

Vision system processing (device) 150 can include various functions software processor and module.These process/modules can be with Including the controller on control camera/sensor and the various parameters of luminaire 130 (by Lighting control information 170) 152.Vision system processing (device) 150 also includes various vision aids 152, such as, property detector (for example, edge detector, Corner detector, blur tool (blob tools) etc.).These instruments are used under illumination and optical condition described below Analyze the surface characteristics and (such as) positioning defect characteristic 140 of image.Vision system processor also includes Defect Search device/look into Module 156 is looked for, the Defect Search device/searching modul 156 positions and recognized the defect on surface using various instruments 154.Can To be quantified to defect and be sent suitable information 172 to processing procedure (for example, part is refused and warning process) 174。

As described further below, in various embodiments, camera 120 can include the polarization (in light path) Optical filter P.Another optical filter PI can be arranged on luminaire light beam being delivered on surface.

With reference to Fig. 2, show vision system arrangement 200, wherein, the exemplary objects 200 with reflective surface directed along Moving direction (arrow M) passes through image scene.Schematically, by destination 212 come mobile object, movement transport Instrument 212 can include mobile station or conveyer.In this embodiment, camera 220 includes sensor S1 and optics OC1. Schematically, in this embodiment, sensor S1 be arranged to 1D pel arrays (or 2D arrays, wherein, one-row pixels are located Reason), so as to be defined to linescan cameras.In one embodiment, camera is operable to that a line of 2D pel arrays can be read Or more row.In such a device, Time-Domain Technique clear to those skilled in the art has been used to carry out the pixel of future voluntarily Information is attached in single image.It therefore, it can mechanically be scanned object, simultaneously continuously read imager to be formed The progressively scan image of part.Therefore, the dimension of camera can be more much greater than the high-contrast area of imaging system or detector. In alternative embodiments, it should be noted that when part remains stationary, imaging/illuminator can also be scanned into a list Member therefore, row scanning would generally it is pair relative with Fig. 1 stationary apparatus, with the region offer high-contrast without linear dimension, its In, high-contrast is concentrated on one point or on a region.However, it has been desirable in certain applications, mobile object device and stationary object device There is advantage.

As described above, optics OC1 is included in the control of diaphragm 224.The illuminated device 230 of scene shines Bright, the line 232 of light is schematically projected to the surface of scene and object 210 by luminaire 230.It is worth noting that, line according to Following manner extends：Parallel to the bearing of trend of sensor pixel array, and it is orthogonal with moving direction M.Camera sensor S1 Be typically normal to/broad sense the surface plane of normal direction object with optics OC1 optical axis OA1, and light the " fan projected Shape (fan) " is oriented to surface plane normal N 1 into non-perpendicular (acute angle) angle A1.Camera is by view data 240 with a series of The form of scan line is sent to visual pattern processor 250.The processor is according to the side similar to above-mentioned processor 150 (Fig. 1) Formula works.In this embodiment, delivery means also send mobile message (for example, being clicked on encoder or impulse form) 242 To processor 250.The information is used for (for example, based on predetermined physical that move along direction M, associated with each pulse Mobile increment) relative to each scan line of physical coordinates spatial registration of object.This enables processor 250 according to a series of The 2D images of 1D pixel column constructed objects.Processor 250 can be that appropriate processing unit is (not shown, but be analogous to above Device 160) a part.Processor 250 also provides Lighting control 270 and based on imager and Lighting control 252, vision The operation of system tool 254 and Defect Search device 256 delivers the appropriate defect information relevant with body surface.These operation classes It is similar to the operation that above-mentioned processor 150 (Fig. 1) is carried out.Camera optics can include polarizer P1, and luminaire 230 Polarizer can equally be included, the function of polarizer will hereinafter be described.

In one embodiment, luminaire can be defined as LED drives, optical fiber lighting device or arbitrarily other are acceptable Luminaire.In any one device, light may be provided in visible ray, infrared light or near infrared light, and other wavelength lights.Should It is noted that in various embodiments, can be realized by both mobile object, mobile camera or mobile object and camera Relative movement between object and camera.Movement can be linear or arc.

II. optical relation

Two kinds of exemplary means 100 and 200 have been described, its be used for gather have comprising surface blemish (such as, hole and Hill defect) reflective surface object image, now will be related to various example surfaces to system in further detail The operation of the system of connection is described.Following description is related to both devices.Such as exemplary (schematic) device in Fig. 3 Shown in 300, pass through example surface 310 of the light source irradiation comprising hill 312 and trench 314 being orientated at on-right angle.Illumination Device 320, which is defined, generally (represent) region of the hot spot (spot) illuminated in large surface 310 (by width by width IS than region IA is represented).The hot spot or surface illuminated is region to be checked, and it can include hill and trench.The base of light 322 illuminated Suitable focusing optics (it can be traditional optics) in luminaire 320 is converged on hot spot, Yi Jisuo The light 324 of reflection is still focused on hot spot 326, either the aperture light near the entrance hole diameter of camera or on the inside of camera On door screen.At any position, the light from surface emitting is mainly by knife edge structure 330 and/or aperture diaphragm (for example, variable lens Aperture) blocked.Relative tilt between camera optical axis 342 based on illumination beam and relative to each other and surface 310, from The light (light 344) of the ramp portion reflection of hill and trench defect is largely transmitted through knife edge structure 330, and enters The entrance hole diameter of optics 340 is to reach sensor 350.Light on the relative slope of each defect is fully from ingate Footpath/optics 340 reflects and/or into knife edge structure 330 (360).

The region of produced image 370 on surface 310 has the form of echo, wherein, the hill 372 of imaging It is that bright (based on from the incident ray 344 towards slope), second half is dark (based on coming from and Slope Facies pair for half Shut out the light 360)；And the trench half of imaging dark (based on shutting out the light 360) and second half is bright (based on coming from face To the light 344 on slope).System can be half dark and which is partly to become clear to open hill and trench resolution based on which, As shown, left-half is bright represents hill, and right half part becomes clear and represents trench.Area around hill and trench Domain is dark relative to the sloped region reflected or brightness less strong region.The shadow brought when slope is towards camera optical axis Ringing result can enable reflected light to focus on the slope, and the deviation (the first deviation) on slope can be produced on lacking The high-contrast change of sunken intensity, and the combination of the inclination and occlusion effect due to knife edge will to come from around defect The light in region can effectively decay.

For a person skilled in the art, it should be apparent that, the installation of device 300 is needed illumination light suitably Shu Chaoxiang slopes and relative to slopes, and make camera towards surface.Or the setting of knife edge-by setting outside tie Structure or mobile adjustable diaphragm are configured --- it be used to strengthen the ideal of the defect in image field required for being used to obtain Light block rank.

III. further application

Above-mentioned vision system arrangement may operate on various objects and surface.Fig. 4 shows row scanning sighting device 400, wherein, row scanning vision system camera 220 (described by Fig. 2) is to movement (mobile M) object 420, the mobile object 420 Passed through from the lower section of row luminaire 230 described above.In one exemplary embodiment, luminaire 230 can include linear Polarizer PI 1 and camera optics OC1 can include orthogonal polarizing filters P1.For example, object can be defined to it is reflective Face, layering surface, such as AMOLED display screens.The example includes the reflection coating provided on glass or sapphire top layer 424 422.It covers polarizer and/or other optical filters and coating 426, and the coating 426 is located at active display layer 428.The master Dynamic layer 428 includes being located at the exemplary hill defect 430 of the top of active layers 428 and positioned at the recessed of the lower section of active layers 428 Paddy defect 440.

Referring again to Fig. 5 and Fig. 6, it illustrates the luminaire light beam being located at relative to camera optical axis OA1 at inclined AP1 510, exemplary (active) AMOLED layers 428 can limit traditional polarization rotating layer, such as, 1/4 λ delayers.Therefore, pass through The illuminating bundle 510 of polarization is sent, device 400 can utilize the inherent attribute of object.Upper surface generally passes through Fresnel reflection To reflect some illumination lights 510.Blocked by the edge of camera optics OC1 entrance hole diameter the wide part.It is remaining The light that the aperture can be entered is blocked by the cross-polarization piece P1 at entrance hole diameter, and cross-polarization piece P1 is oriented to and illuminated Bias slice PI 1 is into 90 degree.The illumination light for penetrating top layer 422,424 passes through 1/4 λ delayers, is reflect off active layers 428, then Second passes through 1/4 λ delayers, so as to be converted into circular polarization from linear bias, after first pass is completed, in being to revert to line Property biasing, be then rotated by 90 ° for second time.The light beam 520 reflected out enters camera optics from surface through polarizer P1 OC1 entrance hole diameter.In this way, the layer including defect (trench in hill and Fig. 6 in Fig. 5) is only reached Light can just be received by imaging sensor, then receive the light of (filtering) by knife fate solution to recognize inclined defect characteristic.

Because the surface of object has different film layer and coating (for example, ARC 422), therefore, preferably It is to provide with infrared or near infrared wavelength region/wavelength period illuminating bundle 510.Reflective surface (for example, AMOLED display screens etc.) On big multicoat and film be used for the light for filtering visible spectrum.Therefore, this is overcome using infrared or near-infrared luminaire The filter effect that a little coatings or film layer are brought due to transmitted illumination light with longer wavelength.It should be noted that Can with combining camera optics during OC1 the knife edge structure KE1 with any acceptable arrangement is set.In one embodiment, its It can be located between lens and polarizer.In certain embodiments, as described below, knife edge can be with polarizer collection Into.

With reference to Fig. 7, in practice it is contemplated that knife edge structure can be applied into camera and optics in a various modes On optical path.The shown basic knife edge structure 710 with blade 712 and bracket 714 is installed in vision system camera Before 730 lens optics 720.Knife edge structure is blinded by a whole aperture AC part, so that when luminaire 750 The inclined illuminating bundle that the knife edge structure can be with luminaire 750 when surface 760 is left in the inclined transmitting of illuminating bundle 740 740 interactions.

Fig. 8 shows another embodiment of device 800, wherein, a pair of light fixtures 810 and 812 are respectively by the He of light beam 820 822 project in the reflective planar defect comprising surface 830.Each light beam 820,822 relative to optics 852 optical axis and regard Feel that the sensor 854 of system camera 850 is tilted along different orientation (being respectively angle 840 and 842).Therefore, light can occur Different reflections (the hill slope opposite with the possibility of trench).A pair of corresponding knife edge structures 860,862 are located at optical inlet Before with respectively shelter reflection light beam 820 and 822.Alternately, the adjustable of optics (lens) component 852 can be passed through Section (double-head arrow 870) aperture 872 provides knife edge to be directed to two light beams.It should be noted that other (two or more) luminaires Surface can be irradiated according to other angles of inclination, and suitable knife edge structure can be used.

Generally, the regulation of lens aperture can be completed in various manners.The situation of regulation ring is provided with mirror body Under, user can rotate suitable high contrast of the regulation ring until obtaining defect while the display of exemplary objects is observed Untill spending image.When lens and/or photomoduel include electromechanical (or other) driving aperture, the process can automatically be held OK.Vision system processor can enable to the defect in acquired image to provide highest contrast by determining which kind of is set Degree difference is set to optimize aperture.

With reference now to Fig. 9 and Figure 10, show has the He of vision system camera optics 910 of 2D pel arrays respectively 912 exemplary vision system 900 and 1000, the vision system camera optics 910 and 912 with 2D pel arrays is used for The 2D images of exemplary stationary object 920 of the collection with reflective surface, including a luminaire 930 (Fig. 9) or multiple (two) Luminaire 1030 and 1032 (Figure 10), both be provided which off-axis illumination with illuminate above described, object 920 reflective surface on Or the hill and trench defect of lower section.The aperture diaphragm associated with optics 912 provides above-mentioned knife edge (generally by element KE2 is represented).Luminaire 930,1030 and 1032 can be LED illuminator (exemplary off-axis LED940 and light as shown Learn device 942), fibre bundle luminaire or other any acceptable headlighting devices.The beam splitter 950,1050 of conventional design Each optical axis 960 and 1060 is disposed parallel to 1052, and luminaire is projected relative to axle 960 and 1060 with an angle of 90 degrees Light beam, it is defined to plate, cube, prism or incident beam can be arbitrarily divided into other of two or more light beams Equipment, these light beams can be with or without identical optical power, and can be orientated or not be orientated an angle of 90 degrees. In this way, the optical axis coincidence with imager is become off axis.This make it that design is compacter, and potentially causes illumination Device can be integrated with camera optics.When having used in Fig. 9 luminaire 930, carried using from opposite side The more uniform image of the defect on surface can be generated for two luminaires 1030,1032 (Figure 10) of illumination.It should be noted that , beam splitter can include a variety of polarizing filters and other light regulating members, including, lens etc..For example, camera can be wrapped Include the polarizer P2 combined with optics 912.Luminaire 930,1030 can be included in the corresponding polarizer PI2 in light path, And luminaire 1032 includes the corresponding polarizer PI3 along device light path.According to as described above (referring to Fig. 5), Polarizer is arranged and worked.

IV. result

Figure 11 shows that the figure according to the embodiments herein as the display image 1100 produced by vision system is represented.Should The surface of object is described in detail in image, identified multiple surface (or sublist face) defects 1110 in the surface of object, 1120th, 1130,1140,1150 and 1160.These exemplary deficiencies are trench (1110,1120,1130 and 1140) or hill (1150 and 1160), its bright half and dark half are oriented in different directions, and it is hill quilt that this, which is depended on, Illuminate or trench is illuminated.Have however, the result due to irradiating run-off the straight, each hill and each trench are all shown The bright half of equidirectional and dark half, and it is unrelated with its size/shape.The processing of other vision systems can be used and lacked Fall into relevant image determine that these defects are indicated whether may not receivable size.

V. the detection and assessment of wavy surface feature

The systems and methods are determined for having fluctuating, waveform or wavy surface feature shape on reflective object Flaw/defect of formula.For example, flat screens can limit (continuous to a certain extent) waveform (wavy) rather than hill Or the region of scrobicula.Although some are wavy be it is acceptable, should be it is contemplated that according to the region of waveform or size These excessive features of (amplitude) can exceed acceptable thresholds, so that it is defective to cause object to look like.

Figure 12 is described in detail by process 1200, wherein, the wavy of reflective surface is determined and assessed.Ripple exists In the step 1210 of process 1200, picture system uses off-axis illumination and knife edge structure as being above generally described to gather can The image on the wavy reflective object surface of energy.Suitable lens can be used to be acquired the image of whole object, or It can be acquired according to row scan mode (being hereafter further described below).Illumination and knife edge device cause most of light Project on surface to be reflect off from imaging sensor optics, or enter knife edge structure, the one of the light reflected It is based partially on wavy or waveform slope and enters imaging sensor.This causes light wave line (for example, line) by dark area institute Surround.The such ripple of some row for looking like bright line is defined in acquired image.

In one exemplary embodiment, various image processing process can be carried out to acquired image data --- it is all Such as, Gaussian smoothing process.

In the step 1220 of process 1200, the whole image intensity map of the pixel in acquired image can be united Meter analysis --- for example, the histogram of pixel (gray scale) intensity and dot frequency in image.With reference to Figure 13, show simultaneously and have There is the histogram of the image of smooth and wavy surface feature.Generally, smooth region shows the intensive intensity point at high-frequency Cloth.On the contrary, wavy region shows the wide-scale distribution (histogram regions 1310 and 1320) of the intensity at low frequency.Cause This, wavy region can be represented by the relatively wide histogram in Figure 14, and smooth region can be by relatively narrow histogram 1500 represent.It should be noted that this is one kind in statistical methods ,-it is usually directed to what some pixel intensity values occurred Degree --- to analyze the smooth region of acquired image and the wavy region of acquired image.

Referring again to the process 1200 in Figure 12, (step is assessed in the distribution to the intensity level in such as histogram 1230).The assessment can include histogram analysis, wherein, for example the grey level distribution to pixel value is calculated, and is generated Histogram buttock line (tail).Then, whether process 1200 is located at the acceptable model of average value for example, by calculating histogram buttock line Interior (steps in decision-making 1250) is enclosed to determine whether there is waveform or other defect.If there is ripple/defect (for example, histogram Buttock line is located at outside average value ranges), then process 1200 is branched off into step 1260.Gone beyond the scope for example, having for each The histogrammic image of buttock line can be limited to a threshold value.The threshold value can be defined by the user or automatically determine.Then, Size and position to all defect in threshold binary image are measured.If the survey of any defect (or aggregation of defect) The result more than desired indicator (it can be defined by the user or automatically configure) is measured, then the indicant body surface of process 1200 The position of specified defect and/or this kind of defect on face.The process can also take other behaviors, such as, and part is refused or sent out Go out caution signal (step 1270).On the contrary, if histogram afterbody does not indicate ripple and/or defect, object is considered as It is acceptable and generally without substantive defect.Such case can be instructed to and/or not take any action (step 1280)。

The said process for assessing the waved surface feature on reflective object can be performed according to row scanning process (1200).Figure 16 and 17 respectively illustrates device 1600 and device 1700, wherein, with exemplary wavy surface feature 1720 The object 1610 of (Figure 17) passes through imaging sensor LS's directed along known (for example, via encoder) mobile (double-head arrow M) Visual field (line 1630).Note, as needed, the mobile MO of scanning is along one of relative direction or along relative direction two Person.Imaging sensor LS is located in camera LSC, and is configured to line scan sensor, and the line scan sensor has a line Pixel is so as to collect the image launched from body surface.Swept by the row in housing LIH in the region of viewing field of camera 1630 The off-axis illumination that the source LI of retouching is provided is illuminated.The light source (LI) can be any acceptable electro-optical device --- for example, one Row LED.The light is focused on by the cylindrical lens 1650 of conventional design and shape, its provide have desired width W1 and The illumination region (crossing moving direction MO through body surface) of indefinite length.Note, in one exemplary embodiment, illumination Line width W1 can be several millimeters or smaller --- but can be with narrower or wider, this depends on the resolution ratio of scanning.Pass through light The corresponding length of source LI and cylindrical lens 1650 determines the length.Cylindrical lens is configured to be spaced one with light source LI Lens mount 1640 is closed, the closing lens mount 1640 provides desired Jiao between the surface 1610 of light source LI and object Away from.In one exemplary embodiment, cylindrical lens 1650 can be defined as semicylinder, the semicylinder and lens mount Be separated between 1649 certain distance and by the line focus on the surface.The off-axis projection of shown light causes the light being launched Most of (planes projected or sector described in Figure 17) of line 1652 is launched (line 1654) to imaging sensor device Outside part (for example, lens aperture) LA, and/or any outside knife edge structure.As shown, it is received by slope The light 1656 that surface is launched is received by linescan cameras LSC.In one exemplary embodiment, positioned at closing lens mount Another cylindrical lens 1660 of 1670 end is by received light focusing to camera optics (knife edge structure LA) In line scan sensor LS.It should be apparent to those skilled in the art that the various camera lights in addition to described cylindrical lens Learn device.As illustrated in FIG. 16, polarizer PI4 can be arranged on light source LI (in the difference along light path At position) light path in.Similarly, polarizer P3 can be arranged in light path received, sensor LS.These elements All it is set, but for the sake of clarity, these contents is not shown in the description of Figure 17 device 1700.

Although it should be noted that having used cylindrical lens shape, various horizontal strokes can be used in alternative device Cross sectional shape --- for example, parabola.Similarly, in addition to lens, mirror can carry out focus illumination light instead of lens.Favorably Ground, lighting device ensures that whole surface continues highly to illuminate and each scanned line completely represents the local oblique of surface Slope.The device can advantageously cause the surface of arbitrary dimension to be imaged and be carried out for pit, hill and ripple Analysis.For example, can be by providing sufficiently long row light fixture and one or more rows scanning phase through body surface Machine carrys out the screen to panel computer or laptop computer, or bigger flat panel TV is analyzed.Each camera can be to whole A part for body object is imaged and provides the independent or stitched together assessment on surface.

It should also be noted that can take explicitly into account, in alternative embodiments, such as luminaire and phenanthrene can be used Alunite ear lens or other Optical devices combine the bigger regional imaging come to object.

VI. line, disk and circular optical mask

Figure 18 shows the diagram of the illustrative examples of broad sense vision system arrangement 1800, broad sense vision system arrangement Including optical module 18030, and the vision system camera component 1810 with imaging sensor 1820.Sensor 1820 is with above-mentioned Generally described mode interconnects (as shown) to vision system processor, and sensor 1820 is gathered Image carry out suitable vision system task.Optical module 1830 can be any acceptable variable or fixed focal length and/ Or variable or constant aperture lens unit, or lens unit combination, for example, traditional M12 type pedestals, F types objective holder or C Type objective holder lens.

According to an illustrative examples, 1832 can be fixed or removable before the optics/lens subassembly 1830 Dynamic mask assembly 1840 is covered.Mask assembly 1840 can screw type or loop tape, or can be via lens group Support (not shown) before part 1830 is mounted.Mask assembly 1840 can also be applied as adhesive applique or directly painting Overlay on before lens subassembly (or other) surface.In the case where screwing means for attachment, mask assembly 1840 can be similar to it The mode of his traditional optical filter operates to combine various lens devices to use, and can be adapted to be thread through tradition thoroughly The end of mirror filtering bench.

Alternatively, mask assembly 1840 can be as needed manually or automatically (for example, via helix tube, servo system System, stepper etc.) come out or enter from the light path of lens.Mask assembly can also limit (such as) as photoelectricity mechanism, the light Motor structure can come impermeable in the fully transparent and part with desired size and dimension via optional control circuit 1850 Change between bright.By non-limiting way, mask assembly 1840 can include window (generally circular), and the window includes The configurable window of LCD shutter or other forms.

Device 1800 includes luminaire 1860 described above, and the luminaire 1860 is oriented to relative to surface 1870 whole plane is into on-right angle (as shown) projection ray.In this example, surface 1870 define along The ripple at least one direction, the ripple includes a series of hills 1872 and the groove 1874 between hill.It is angled Light hits these hills and groove, and scattered by these hills and groove, and light is partly into camera opticses component 1830. Mask assembly 1840 defines knife edge element according to its various forms, and the knife edge element causes most scattering optical attenuations, and only Only by the light orientation sensor 1820 with specific limited angular range.In this embodiment, the mask for covering/coating by Dotted line 1880 represents that it includes center coverage 1882 and external coverage areas 1884, center coverage 1882 and outside There is hatch bore diameter, the transmitting light 1890 from surface 1870 passes through the hatch bore diameter between overlay area 1884.Various In embodiment, polarizer PI5 is combined with luminaire 1860, and corresponding polarizer P4 can be arranged to and optics/lens group Part is combined.According to (for example, Fig. 5), being arranged and work to polarizer as upper described as generally noted above.

Figure 19 shows the more detailed example according to the vision system of illustrative examples arrangement 1900.The embodiment bag Include similar to the beam splitter and polarizer device shown in above-mentioned Fig. 9 with description.Specifically, device 1900 includes photomoduel 1910 and lens/optics 1920.According to the embodiments herein, lens/optics 1920 includes mask assembly 1930. It is the polarizer P5 worked according to above-mentioned principle before mask assembly 1940, beam splitter 1950 is set, from examined The reflected light of object 1960 is transmitted to camera 1910 by the beam splitter 1950.Light fixture 1970 is set.Light fixture 1970 include light source 1972 and collector lens 1974.Polarizer PI6 is provided with before collector lens.It should be noted that Polarizer P5 can include the mask pattern positioned at its surface, and the component can be configured to be attached to before lens 1920 The screw-on or buckle type annex in face.

According to an illustrative examples, there is provided another vision system arrangement 2000.The device 2000 includes camera Component 2010 and lens/optics 2020.According to the embodiments herein, lens/optics 2020 includes mask assembly 2030.It is the polarizer P6 worked according to above-mentioned principle before mask assembly 2040, beam splitter 2050 is set, from quilt The reflected light of the object 2060 of inspection is transmitted to camera 2010 by the beam splitter 1950.In this embodiment, beam splitter Collector lens 2070 is provided between 2050 and object 2060.The concentrator and the binding operation of light fixture 2080, light fixture 2080 include light source 2082, condenser lens 2084 and polarizer PI7.It should be noted that can be according to for this area skill Known optical principle clear to art personnel formulates the size of condenser lens 2084, collector lens 2070 and other optical components And these optical components are configured.

The center coverage and external coverage areas of above-mentioned various mask assemblies can limit various geometries, size And relation.Suitable mask can be selected by experience or trial-and-error method, to realize to examined given surface most Good image.This is described in further detail in Figure 21 into Figure 27, these diagram covering there is provided all kinds/size Mould pattern.

With reference to Figure 21, during a form of mask 2100 of generation knife edge is defined in transparent linear aperture 2120 Entreat impermeable open-wire line 2110.The perimeter 2130 of the remaining mask around transparent aperture 2120 is also opaque.Line 2110th, 2120 be oriented to be substantially parallel to surface feature ripple (if any) direction of elongate, and this shape The mask of formula is maximally effective under this kind of situation.More generally, as needed, elongated direction by rotation by (for example, covered Mould) select to strengthen or suppress surface characteristics.By non-limiting example and in order to more fully understand the function of device, aperture Width WLA be variable, for example, for diameter D0 for for 50-55 millimeter of lens, WLA between 5 millimeters and 10 millimeters it Between, and central impermeable open-wire line WL is between 1 millimeter to 5 millimeters.Generally, the width WL of line being dimensioned to and coming from The width of the focal beam spot of luminaire matches.It should be noted that assuming that each following mask set (Figure 22 to 27) has Similar lens diameter D0.For the lens of larger or smaller diameter, overall dimension can proportionally change.

Figure 22 shows the mask 2200 of central opaque, circular (stop) disk 2210 including a diameter of DD.The disk Desired knife edge element is provided for device.Generally, the size of disk is selected to and treated surface characteristics that is enhanced or suppressing The size of (for example, defect) matches.It should be noted that edge (broken circle of the example mask device 2200 to lens 2230) without any outside zone of opacity, and all it is transparent.The basic knife edge element makes it possible in hill and groove Given angle in the range of receive light, these hills and groove can be oriented on the surface at various orientations.

Figure 23 shows central opaque (stop) disk 2310 with diameter DD1 (being about 9 millimeters), and with internal diameter DA (being about 14 millimeters) annular opacity perimeter 2330.Difference between disk diameter DD1 and perimeter 2330 Transparent ring-like window 2320 is generated, the light reflected from surface can be passed through from the transparent ring-like window 2320.It should be noted that , the diameter of center resister disk defines the degree of light attenuation in the way of knife edge element, and in order to strengthen definition, ring The diameter of shape perimeter defines the confocal effect of optical system.

Mask configures 2400,2500,2600 and 2700 one is described in corresponding Figure 24, Figure 25, Figure 26 and Figure 27 Other a little examples, its central barrier disc and outer annular regions define annular aperture therebetween.Pass through non-limiting example Mode, the disk diameter DD2 of mask 2400 is about 5 to 6 millimeters, and outer annular regions internal diameter DA1 is about 8 to 9 millimeters. The disk diameter DD3 of mask 2500 is about 3 to 4 millimeters, and outer annular regions internal diameter DA2 is about 5 to 6 millimeters.Mask 2600 disk diameter DD4 is about 3 to 4 millimeters, and outer annular regions internal diameter DA3 is about 8 to 9 millimeters.Mask 2700 Disk diameter DD5 be about 5 to 6 millimeters, and outer annular regions internal diameter DA4 is about 10 to 12 millimeters.These dimensions are only Only it is the example of the wide scope of possible dimension, it can be adjusted for the respective following feature on examined surface, all Such as, angle, illumination intensity and/or the wavelength of vision system arrangement.

As described by general above, can by using various technologies (for example, printing, photoetching, using with print Transparent membrane of brush or moulded pattern, etc.) coating with appropriate pattern is applied to class glass of color filter surface to construct Mask.It will be clear for those skilled in the art that various technologies can be used to apply fixed mask pattern to camera Optics.Similarly, as described above, mask, which can be limited, includes the active component on such as pixelation surface. Or what is separated with vision system processor is that the controller of a part for vision system processor optionally handles work Each pixel of property mask is to generate the mask pattern for having desired shape and size.It should be noted that controller can be with It is adapted to by various configurations, until user or automatic vision systematic procedure (for example, based on contrast) determine that optimal pattern is set Put.The shape of pattern can be similar to the shape described by Figure 21 to 27, or can have more complicated shape with preferably It is consistent with unique surface characteristics and/or wave pattern.

It should be noted that in certain embodiments, can use and be interconnected with one or more vision system processors Multiple cameras.Each camera can have from identical or different angle acquisition different sizes and/or the mask of configuration (for example, Various sizes of barrier disc) body surface image, and surface multiple images can be analyzed with ensure have difference The corrugation patterns of size, shape and/or orientation are suitably imaged.Similarly, it is variable (by optics in mask Different masks are above placed, otherwise the pattern by changing mask) in the case of, multiple images can be acquired and be divided Analysis.

With reference to Figure 28 image 2800, the tradition for the hand-held device being imaged according to above-described embodiment using mask is shown Touch-screen.In the images, either visually observe, or regarded by multiple tradition without characteristic surface with relatively flat Feel system is arranged, can clearly identify external waviness.In Figure 29, image 2900 also show be not ordinarily visible thin Section, in this example, sensor matrices/array 2910 of touch-screen.Further shown by the example images in Figure 30 The level of detail realized using mask described herein and imaging technique, wherein, in the region of touch-screen closely Each wire 3010 in the array 2910 in Figure 29 can be clearly identified in figure.

VII. conclusion

It should be understood that said system and method provide a kind of effective technology to be used to recognize multiple layerings and do not divide Include the slope defect and waveform/uniformity defect of hill and trench defect on layer reflective surface.By the photograph for taking suitable wavelength Mingguang City and filter plate (for example, various polarizers), system and method can be effectively to the surfaces with various coatings and layering Imaging., it may be desirable to which schematic knife edge device can be distinguished according to defect in which side causes what is reflected from hill or trench Light either become clear relative to background otherwise dark defect the gradient (first derivative).The size of defect may be oblique with defect Slope is directly proportional.Less defect can have the less gradient, and it can make it that the less illuminating ray from background is deflected.Light source Small spatial dimension make it that it a small amount of focus on is occurring after examined surface emitting so that it is in no stop defect light In the case of can more easily stop background.However, the light source more extended can reduce the inclined negative effect in random test surface, This can run into production environment, to reduce defect contrast as cost.Therefore, knife edge is by reducing by stopping background light Background increase contrast.In addition, schematically using slope, shape and Polarization Detection cause most of bias light by from The aperture reflective of camera and filter, and the light from slope defect is focused in the camera with high-contrast.In addition, exemplary Device generally makes it possible to the reflective surface applied to wide variety of sizes by using linescan cameras and focus illumination line.Also embody Herein provide a mask, including a blade member and other elements (such as confocal element) it is highly refined there is provided one

The illustrative examples to the present invention are described in detail above.In the spirit and model without departing from the present invention In the case of enclosing, various modifications and addition can be carried out.As needed, the feature of each embodiment in each above-mentioned embodiment It can be combined with the feature of described other embodiment, in order to provide the multifarious feature group associated with new embodiment Close.Although in addition, described above is multiple independent embodiments of the device and method of the present invention, described content is only Only it is the schematic description of the application of the principle of the present invention.For example, term as used herein " process " and/or " processor " should Taking basic function and part widely including various electronic hardware and/or software (alternately, can be referred to as " module " Or " element ").In addition, described process or processor can be combined with other processes and/or processor, or it is divided into Subprocess or sub-processor.According to the embodiments herein, such subprocess and/or sub-processor can be combined differently. Similarly, it should be clearly that consideration, any function, process and/or processor herein can use electronic hardware, by having The software being made up of the non-volatile computer-readable medium of programmed instruction, or the combination of hardware and software are realized.In addition, Used various orientations and arrangement term, such as " vertical ", " level ", " on ", " under ", " bottom ", " top ", " side " is " preceding Face ", " below ", " left side ", " the right " etc., are used only as relative to fixed left side space, owner, the action direction of gravity, phase To agreement rather than absolute direction/arrangement.In addition, term " generally " or " about " are special relative to measure across subjects or measurement Levy to use, it refers to the amount in normal operation range for reaching expected result, and still, it is included due to being System the deviation allowed in intrinsic inaccuracy and error and cause some change.Therefore, this description should only be made To be exemplary, and and non-limiting the scope of the present invention.

Claims (26)

1. a kind of system for being imaged to the defect on the reflective surface of object, the system includes：

Vision system camera, the vision system camera has imaging sensor and optics and limits an optical axis, and this is regarded Feel that system camera is directed to be imaged the surface；

Device assembly is illuminated, the illumination device assembly is with the predetermined angle not parallel with the optical axis by the light beam projecting constructed to institute State surface；And

Knife edge element, the knife edge element is associated with the optics, and the knife edge element changeably covers described A part for the maximum field of view of optics, wherein, the knife edge element and the predetermined angle be each arranged to so that：By institute Optics is stated to be reflected, generally penetrate ramped shaped hill and trench on the surface into the light of the sensor, And the reflection light around the ramped shaped hill is by the knife edge element covers.

2. system according to claim 1, wherein, the knife edge element includes the variable aperture in the optics.

3. system according to claim 1, wherein, the predetermined angle is related to the gradient of the hill and the trench Connection.

4. system according to claim 1, wherein, the sensor is 2D sensors, and the object is relative to institute State camera static.

5. system according to claim 1, wherein, the arrangement of the sensor definition linescan cameras, and the thing Body phase is moved for the camera.

6. system according to claim 5, wherein, the illumination device assembly projects to illuminating line on the surface.

7. system according to claim 6, wherein, illumination is generally limited to IR or near-ir wavelengths scope.

8. system according to claim 7, wherein, the object defines the layer including ARC.

9. system according to claim 8, wherein, the layer includes polarization layer, and the illumination is polarized and the light Learning device includes polarizing filter.

10. system according to claim 9, wherein, the object is AMOLED display screens, and the polarization layer is 1/ 4 λ delayers, and the polarizing filter are defined to orthogonal polarizing filters.

11. system according to claim 6, wherein, the luminaire includes the polarizer for polarization illumination, Yi Jisuo Stating optics includes polarizing filter.

12. system according to claim 1, wherein, the light source defines aggregation light beam, the aggregation light beam direction A little restraining near the knife edge structure.

13. system according to claim 1, wherein, the knife edge structure qualification external structure, the external structure position In light path before the optics.

14. system according to claim 1, wherein, ray cast is placed through the vision by the illumination device assembly Beam splitter on the optical axis of system camera so that the off-axis illumination for coming from the illumination device assembly is projected to by the beam splitter With the body surface of the optical axis coincidence.

15. system according to claim 1, wherein, the illumination device assembly defines multiple light sources, wherein each shine Ray cast to each beam splitter, each beam splitter are located on the optical axis of the vision system camera by bright source so that：Come from The off-axis illumination of the illumination device assembly is projected to the body surface with the optical axis coincidence by the beam splitter.

16. system according to claim 5, wherein, imaging len is defined as row imaging len, and, the illumination Device assembly is projected on the surface, is then focused into as a focal line, and it is saturating that the focal line falls on the imaging after reflection The outside of the entrance hole diameter of mirror.

17. system according to claim 16, wherein, the illumination device assembly includes cylindrical lens, for focusing on out State focal line.

18. system according to claim 1, wherein, feature is defined as the ripple on the region on the surface, and institute Stating system also includes analysis and evaluation process, and the analysis and evaluation process are determined in described image sensor acquired image Pixel intensity value must be distributed and by it is described distribution be compared with threshold value.

19. system according to claim 18, wherein, by least one of the image pixel intensities respective frequencies in described image Histogram limits the distribution.

20. system according to claim 1, wherein, the knife edge element is defined in the optics, positioned at described Barrier structure on optical axis, the barrier structure, which is located at, is configured to the mask member adjacent with before the optics On, the barrier structure is configured to be strengthened or suppressed optionally for the scattered light associated with the feature.

21. system according to claim 20, wherein, the barrier structure defines a line, and the line passes through the optics Device extend along prolonging direction and with it is relevant with the size of the focus illumination hot spot on the optics, along horizontal stroke The width on the direction of the prolonging direction is worn, and, wherein, the prolonging direction is limited by the orientation of the feature.

22. system according to claim 21, wherein, the mask member is included on each opposite side of the line Surrounding's zone of opacity, between the line and the zone of opacity have linear aperture.

23. system according to claim 20, wherein, the barrier structure includes disk, and the center of the disk is about On the optical axis and with the diameter relevant with the size of one or more of the feature.

24. system according to claim 23, also including annular region, the annular region be located at around the disk and The annular aperture between the annular region and the disk is defined, the annular region is configured to suppress scattered light.

25. system according to claim 20, wherein, the mask member defines one of at least following part：Hasp Formula or screw-on lens cover, the applique of top before the optics and on the optics Changeable mode photoelectricity mechanism.

26. system according to claim 20, also including be configured to be combined with the optics the first polarizer with And be configured to illuminate the second polarizer that device assembly is combined with described.