Summary of the invention
The present invention considers above-mentioned situation just, its purpose is to provide a kind of edge sensor of the above-mentioned object edge of the light quantity distribution pattern detection position that Fresnel diffraction produced from object edge, especially can reliable detection goes out the edge sensor of defectives such as the breach that produces such as this transparent or semitransparent object of liquid-crystalline glasses or cracking.
Simultaneously, its purpose of the present invention is, provides a kind of and can use above-mentioned edge sensor, detects the flaw detection apparatus of rejected regions such as the breach that produces such as this transparent or semitransparent object of liquid-crystalline glasses or cracking accurately.
In order to achieve the above object, edge sensor of the present invention comprises: a plurality of photosensitive units are arranged the linear sensor that forms with predetermined distance; With the light source of monochromatic collimated beam towards this linear sensor projection; And the output of described linear sensor analyzed the operational part that comes its ad-hoc location of object (edge) to the light path that is arranged in described monochromatic collimated beam to detect, it is characterized in that,
Described operational part for example constitutes from the free space side output search of described linear sensor is analyzed light quantity distribution pattern on the described linear sensor, especially comprises:
(A) primary importance detection means, to drop to the light quantity with free space be that the position of the first light quantity threshold value determined of benchmark is obtained as first detection position of described object to light quantity when it will be to the light quantity distribution pattern that the edge produced of transparent or semitransparent object be searched for towards the other end from the one end;
(B) second place detection means, it will be that the position of the second light quantity threshold value determined of benchmark is obtained as second detection position of described object from increasing to light quantity with described free space after the detected first detection position light quantity further descends.
In addition, can set respectively for the described first and second light quantity threshold values, also can be used as identical value provides.
Flaw detection apparatus of the present invention is characterized in that, constitutes the edge sensor with above-mentioned formation, comprising:
(a) scanning means, it makes the described linear sensor in the described edge sensor move along the edge of described transparent or semitransparent object, or make transparent or semitransparent object with described edge sensor in the direction that intersects of linear sensor on move; And
(b) defects detection means, its scanning with described linear sensor or described object monitors detected respectively first detection position of described first and second position detection means in the described edge sensor and the variation of second detection position, and carries out regulation such as give a warning and handle when the variable quantity of first or second detection position surpasses pre-set threshold.
Another flaw detection apparatus of the present invention is characterized in that, constitutes the edge sensor with above-mentioned formation, comprising:
(c) shading width detection means, it is obtained detected respectively first detection position of described first and second position detection means in the described edge sensor and the difference of second detection position as the shading width;
(a) scanning means, it makes the described linear sensor in the described edge sensor move along the edge of described transparent or semitransparent object, or make transparent or semitransparent object with described edge sensor in the direction that intersects of linear sensor on move; And
(d) defects detection means, its shading width of described shading width detection means being obtained with the scanning of described linear sensor or described object monitor, and give a warning when this shading width surpasses pre-set threshold.
In addition, also constituting described transparent or semitransparent object is glass plate, and described defects detection means detect the breach of above-mentioned glass plate edge or cracking or even recess (making the big breach of edge line distortion) and send and show the warning that has defective.
(invention effect)
Adopt the edge sensor of above-mentioned formation, detecting its light quantity from the light quantity distribution pattern that the edge produced of object, to drop to light quantity with free space be first detection position (for example marginal position) of the position (position of bigger variation takes place light quantity) of the first light quantity threshold value determined of benchmark as described object, and above-mentioned object is transparent or semitransparent, therefore the big variation portion of the light quantity that object side produced being compared with first detection position that detects as mentioned above is that second detection position of the second definite light quantity threshold value of benchmark detects as increasing to light quantity with free space after further descending from the above-mentioned first detection position light quantity, so can judge whether the edge of above-mentioned object exists defective according to the relation of above-mentioned two detection positions.
Specifically, under the situation of defectives such as the marginal existence breach of object, cracking, the transmittance effect of transparent or semitransparent interior of articles changes because of these defectives, its light quantity distribution pattern is just different with the light quantity distribution pattern that normal edge produced that does not have defective, thereby can be easy to judge according to above-mentioned two detection positions the variation of this light quantity distribution pattern.Therefore, can be easy to judge according to the relation of above-mentioned two detection positions whether object edge exists defective.
And adopt flaw detection apparatus of the present invention, above-mentioned linear sensor in the edge sensor is moved along the edge of above-mentioned transparent or semitransparent object, or make transparent or semitransparent object with above-mentioned edge sensor in the direction that intersects of linear sensor on move and obtain above-mentioned first and second detection positions respectively, obtain the trend of the above-mentioned detection position that detects, thereby can detect breach or cracking defect from the variation of above-mentioned two detection positions, and the detection location information (scanning position information) that can be easy to the above-mentioned detection position when detecting defective is determined this defective position.
So, can be conceived to the variation of the light quantity distribution pattern at its edge of transparent or semitransparent object, simple and easy and detect defectives such as the breach of marginal existence of above-mentioned object or cracking effectively, thereby its practical advantage is bigger.
Embodiment
Illustrate with reference to the accompanying drawings an embodiment of the present invention edge sensor, use the defect detecting device of this edge sensor.
Fig. 1 detectsedge sensor 10 such as the ad-hoc location (for example marginal position) of transparent or semitransparent object A such as liquid-crystalline glasses, monitors that the output of above-mentionededge sensor 10 detects the cardinal principle pie graph that flawless defect detecting device is arranged among the above-mentioned object A when utilizing the position probing object position of 10 couples of above-mentioned object A of this edge sensor to scan.
Thisedge sensor 10 comprises following formation:optical head 13, and it separates with predetermined distance a plurality of photosensitive units, and predetermined distance is relative to be disposed by line spreadlinear sensor 11 that forms and thelight source 12 that monochromatic collimated beam is throwed towards thislinear sensor 11; Andarithmetical unit 14, the ad-hoc location (for example marginal position) of the object A that puts in the light path that detects above-mentioned monochromatic collimated beam is analyzed in its output to above-mentionedlinear sensor 11.
In addition, the basic structure of optical head 13 (formation) is disclosed as No. 3858994 communique of above-mentioned patent and 2007-No. 64733 communiques of TOHKEMY etc., is well-known.In addition, the scanning at the position probing object position of 10 couples of above-mentioned object A of above-mentioned edge sensor is to be undertaken by above-mentioned linear sensor 11 (optical head 13) in the above-mentionededge sensor 10 is moved along the edge of above-mentioned transparent or semitransparent object A.Perhaps make on the contrary above-mentioned transparent or semitransparent object A with above-mentionededge sensor 10 in the direction that intersects oflinear sensor 11, the direction that particularly intersects with the orientation of a plurality of photosensitive units on move and carry out this scanning.
And above-mentionedarithmetical unit 14 is realized by for example CPU, has thefunction 15,16 that light quantity distribution pattern on the above-mentionedlinear sensor 11 that the edge of above-mentioned object A is produced according to the output of thislinear sensor 11 is analyzed the ad-hoc location of calculating above-mentioned object A (for example comprise marginal position in interior first and second detection positions of explanation after a while).Here, in general above-mentioned light quantity distribution pattern is the pattern of the Fresnel diffraction of above-mentioned monochromatic collimated beam generation.
In addition, when above-mentioned arithmetical unit 1 constitutes its sensitive volume at the free space that is not covered by above-mentioned object A basically of above-mentionedlinear sensor 11 is normalized to " 1 ", its sensitive volume of rising edge part of above-mentioned light quantity distribution pattern is detected for the detection position (marginal position) as above-mentioned object A, the position of " 0.25 ".In other words, to constitute on the light quantity distribution pattern of above-mentioned Fresnel diffraction its light quantity be that the position of the definite regulation light quantity threshold value " 0.25 " of benchmark is detected as the ad-hoc location (marginal position) of object A for the light quantity " 1 " with the free space place to above-mentionedarithmetical unit 14.
Among the present invention, object A as detected object is transparent or semitransparent, therefore be conceived to such situation, be above-mentionedlinear sensor 11 output as shown in Figure 2, not only do not have the sensitive volume of the free space that object A exists more, and the residing part of above-mentioned object A is because the monochromatic collimated beam of this object of transmission A arrivelinear sensor 11 thereby its sensitive volume is also more.And object A is under the situation of occulter, and the marginal portion sensitive volume does not have great decline, but object A is under the transparent or semitransparent situation, only because of the influence of Fresnel diffraction causes its sensitive volume to a certain degree reduction is arranged in the marginal portion of object A.And under the situation of defectives such as the marginal existence breach of above-mentioned object A or cracking, can be subjected to the influence of diffraction at random, refraction or even diffuse reflection etc. of the above-mentioned monochromatic collimated beam of this defect part.In this case, the situation that produces Fresnel diffraction with the edge (knife edge) of linearity is compared, and above-mentioned sensitive volume descends (falling (Luo ち Write む)) width at position enlarges.
Specifically, as Fig. 3 (a)~Fig. 3 (d) shown in respectively to detect transparent substance be the detection position of liquid-crystalline glasses withoptical head 13 timelinear sensor 11 output such, whether the distribution patterns of its sensitive volume exists defective to produce difference with the edge of above-mentioned liquid-crystalline glasses.Fig. 3 (a) is the photosensitive profile pattern that does not have the marginal portion of defective existence, Fig. 3 (b) is the photosensitive profile pattern of marginal portion when having small breach, Fig. 3 (c) is the distribution patterns of marginal portion when having cracking, and the distribution patterns during Fig. 3 (d) to be the marginal portion exist recess that breach causes.
Sensitive volume distribution patterns shown in Fig. 3 (a)~Fig. 3 (d) difference is visible like that, compare with the situation that the edge of object A does not have defective to exist, exist the light quantity of the situation lower limb part of defectives such as breach or cracking to fall increase, and the width that light quantity is fallen enlarge.No matter but the detected light quantity falling position of free space side has zero defect all almost not change.And its falling position of the detected light quantity of object side has bigger variation with defect kind, its degree, and it falls mode (light quantity change pattern) various variations also take place.The detection position exists under the situation of defective, allows the wide sensitive volume that causes position its object A side of even transmission that bigger inequality is arranged originally.
Therefore,edge sensor 10 of the present invention constitutes has primary importance detection means 15 and second place detection means 16, when the free space side of the never above-mentioned object A of output of 15 pairs of above-mentionedlinear sensors 11 of primary importance detection means begins to search for, the Fresnel diffraction that produces with the edge of above-mentioned object A according to light quantity and the part that sharply descends is obtained the first detection position α of above-mentioned object A, and the position that second place detection means 16 will increase after will further descending from the first detection position α sensitive volume that this primary importance detection means 15 is obtained is again obtained as the second detection position β of above-mentioned object A.
In addition, in the present embodiment, sensitive volume for example be that is to say that from the position that the normalization light quantity " 1.0 " of free space side drops to " 0.825 " position that drops to the predefined first and second light quantity threshold values detects respectively as the above-mentioned first and second detection position α, β.Here, be identical value " 0.825 " for the first and second light quantity threshold settings, but also can be set at the value that differs from one another.And, in the present embodiment, particularly by beginning the output of above-mentionedlinear sensor 11 is searched for from the free space side, no matter thereby the whether irregular variation of the sensitive volume that produces because of defective of object A side, can detect reliably respectively determine with the corresponding sensitive volume in detection position (marginal position) of object A fall the part required first and second detection position α, β.Begin to search for good but constitute to the output of above-mentionedlinear sensor 11 from object A side.And when carrying out sensitive volume normalization, can measure the light quantity of free space under the state that object A is not set in advance stores, and when detecting, carry out normalization according to this value, perhaps handle the sensitive volume less zone that descends good as free space according to testing result.
Use by the information of the detection position (the first and second detection position α, β) ofsuch edge sensor 10 detected object A to come the flaw detection apparatus that above-mentioned object A carries out defect inspection is comprised the scanning means (scanning mechanism) 21 that move the detected object position of 13 couples of object A of above-mentioned optical head detection position along the edge of this object A.These scanning means 21 can be have make object A along its edge the parallel object supporting mechanism (not shown) that moves this function, also can be make on the contrary above-mentionedoptical head 13 along the edge of above-mentioned object A parallel mobile optical head travel mechanism (not shown).That is to say, scanning means 21 can be make object A with direction thatlinear sensor 11 intersects on parallel moving, also can be make on the contrarylinear sensor 11 along the edge of object A parallel moving.
Except such scanning means 21, above-mentioned flaw detection apparatus also comprises defects detection means (tendency judgement means) 22, these defects detection means 22 are handled by the detection of carrying out above-mentioned arithmetical unit (CPU) 14 couples of above-mentioned first and second detection position α, β with the scanning at above-mentioned position probing object position one by one, and monitor the edge of inspected object A that defectives such as non-notch or cracking are arranged to the variation of its output (the first and second detection position α, β).In the present embodiment, the above-mentionededge sensor 10 detected first and second detection position α, β information once are stored in the storer 23, the change pattern (variation tendency) of first and second detection positions are read in the above-mentioned defects detection means 22 be used for defect inspection then.
And in the above-mentioned defects detection means (tendency judgement means) 22, when for example amplitude of variation of the above-mentioned first detection position α or the second detection position β has surpassed predefined permission amplitude, it is judged to be " defectiveness ".There is the position in defect inspection position (scanning position) detection of above-mentioned object A in the time of will being judged to be " defectiveness " simultaneously for defective.At the permission amplitude of the amplitude of variation of the first detection position α or the second detection position β, can set according to the rectilinearity degree that object A edge is required.
Above-mentioned defects detection means (tendency judgement means) 22 also can detect the difference of for example above-mentioned first detection position α and the above-mentioned second detection position β width (shading width) that falls as the light quantity in the above-mentioned light quantity distribution pattern, and the variation of above-mentioned detection position α, β poor (light quantity fall width) monitors when scanning above-mentioned object A edge.And when surpassing predefined permissible value, it is judged to be " defectiveness " when the difference of detection position (light quantity fall width).In this case, there is the position in defect inspection position (scanning position) detection of the above-mentioned object A in the time of also will being judged to be " defectiveness " for defective.Permissible value at the difference of above-mentioned detection position (light quantity fall width) can be set according to the rectilinearity degree that object A edge is required.
Like this, this flaw detection apparatus constitutes and utilizes above-mentionededge sensor 10 that the detection position of transparent or semitransparent object A is detected respectively as the above-mentioned first and second detection position α, β, makes this position probing object position monitor the situation of change (variation tendency) of the above-mentioned first and second detection position α, β when this edge moves.Thereby, when adopting this device to work as to detect the variation of the first and second detection position α, β to surpass predefined permissible value, or the difference of first detection position α and the second detection position β is detected. as defectives such as object A marginal existence breach or cracking when having surpassed the permission amplitude reliably.Simultaneously, adopt this device to which position at object A edge to exist defectives such as breach or cracking to detect.
It is the situation of change of the example first and second detection position α, β when carrying out rim detection that Fig. 4 (a) illustrates with liquid-crystalline glasses jaggy.In this example, for the first detection position α, almost can't see variation, but, then see bigger variation at the width range that is equivalent to barbed portion for the second detection position β.It is the situation of change of the example first and second detection position α, β when carrying out rim detection that Fig. 4 (b) then illustrates with the liquid-crystalline glasses that cracking is arranged.And in this example, for the first detection position α, also almost can't see variation, but for the second detection position β, then see bigger variation at the width range of the part that is equivalent to ftracture.
And Fig. 4 (c) illustrates is that liquid-crystalline glasses with the jagged recess that causes is the situation of change of the example first and second detection position α, β when carrying out rim detection.In this example, for the first detection position α, can see variation slightly at the recess position, but, then see bigger variation at the width range that is equivalent to the recess position for the second detection position β.Fig. 5 (a)~Fig. 5 (c) is corresponding with Fig. 4 (a)~Fig. 4 (c) respectively, is the situation of change that transverse axis illustrates the first and second detection position α, β with the amount of movement ofedge sensor 10 or translucent body A.Edge detection results is shown so also can be seen and the identical trend of situation of change shown in above-mentioned Fig. 4 (a)~Fig. 4 (c).
Therefore, as mentioned above according to flaw detection apparatus of the present invention, wherein adopt the present invention except the first detection position α that common edge sensor detected, also to detect theedge sensor 10 of the second detection position β, and the above-mentioned first and second detection position α during to scanning object A edge, the situation of change of β monitor, just can reliable detection go out tiny flaws such as breach that the edge of object A such as liquid-crystalline glasses produces and cracking.But also can detect the position at above-mentioned defective place, therefore have great practical advantages aspect the quality management of for example liquid-crystalline glasses.
And, wish to constitute detecting the execution compulsory exercise corresponding under the situation of defective with it.Compulsory exercise can be meant for example sends warning or this action command of alarm, perhaps constitutes the removal device that object A is removed in the middle of the operation as substandard products is set in addition, and takes certain means instruction this to be carried out this content of this removals processing.Thus, can be easy to tackle the product that has defective.
But in a single day the edge of object A exists defectives such as breach or cracking, just as with reference to Fig. 3 (a)~Fig. 3 (d) is illustrated, also can change at object A side sensitive volume.So, do not having dirt on the transparent or semitransparent object A and can guarantee under the stable situation of the light quantity of this object A part (interior of articles), for example also can obtain the light quantity distribution shown in Fig. 3 (a) of the inner side of normal object A in advance, will compare with above-mentioned light quantity distribution as the light quantity distribution of the inner side of the object A that checks object and carry out defect inspection.Light quantity distribution as its private side of object A of checking object is tried to achieve shown in Fig. 3 (b)~Fig. 3 (d) respectively, when different, also it can be judged to be defectives such as having breach or cracking with the light quantity distribution of the normal object A shown in Fig. 3 (a).The method of this method and the variation of above-mentioned judgement second detection position is used in the lump, just can further be detected the tiny flaw at object A edge.
The present invention is not limited to above-mentioned embodiment.For instance, be not specific for above-mentioned " 0.825 " to the first and second light quantity threshold values on the basis that detects the first and second detection position α, β, but according to detect the edge when not having the detection position of transparent or semitransparent object A of defective the light quantity of marginal portion fall degree and set and get final product.In addition, for the detection width oflinear sensor 11, determine to get final product according tolinear sensor 11 and object A distance (operating distance) between the two etc.In addition, the present invention can carry out various distortion and implements in the scope that does not break away from its essence.