DE102006059320A1 - Defects e.g. streaks, detecting method for e.g. DVD, involves differentiating dust particles deposited on solid e.g. plastic body, from fluorescent defects due to their shape and/or size and/or color of emitted fluorescent light - Google Patents

Abstract

The method involves subjecting a solid (124) e.g. plastic body or plastic foil, to light from a light source (106) e.g. blue LED, and detecting the fluorescent light produced by the action of the light of the light source on the solid. The fluorescent light is subsequently analyzed by image processing, and dust particles (136, 138) deposited on the solid are differentiated from the fluorescent defects (130, 132, 134) due to their shape and/or size and/or the color of the emitted fluorescent light. An independent claim is also included for a device for detecting defects in a transparent solid.

Description

The The invention relates to a method for detecting defects in a solid and a device for implementation of the procedure.

transparent Solid, such as transparent plastics, are everyday objects and come in many different forms and uses. To exist z. As optical data storage such as CDs, DVDs, etc. largely made of plastics, as a carrier material be used in the optical data storage and for the Reading light used are transparent. In the automotive industry also innumerable Used plastics. As an example, here is the disguise of Motor vehicle headlights, which is visible to the outside, called become. Such panels are for the generated in the headlight Light transparent.

Defects, especially macroscopic defects in the solids cause that the solids in certain circumstances not for anymore their original intended use can be used. For example, it influences a macroscopic error in the fairing of a motor vehicle headlight the appearance of the entire vehicle disadvantageous if this accordingly is great. Furthermore, the light generated by the headlight can be at the defects be scattered, leading to a possibly significant reduction the functionality of the vehicle leads. In usually manufacturers of these panels are interested in Such coverings do not even extradite to the car manufacturer and therefore these mistakes already during to detect the production and the corresponding panels as To screen rejects. As mentioned above, defects in the substrate lead CDs, DVDs, etc. errors in reading the stored Dates. Manufacturers of CDs, DVDs etc. are therefore interested in Plastic body with flaws not even to use for the production of CDs.

task The invention therefore provides an improved method for detection indicate defects in transparent solids. Object of the invention it is also an improved device for the detection of defects in the solids specify.

The The objects underlying the invention are with the features solved the independent claims. embodiments of the invention are in the dependent Claims specified.

According to the invention is a Method for detecting defects in a transparent solid specified. According to the procedure the impingement of the solid with light from a first light source. Furthermore, the detection takes place when applying the solid fluorescent light generated by the light. In a further process step the image processing of the fluorescence light takes place. It will be on the solid deposited dust particles due to their shape and / or size and / or the color of the emitted fluorescent light from the fluorescent A distinction made between flaws.

fluorescent Defects in the solid can be according to the invention thereby detects that the solid state is acted upon by light of the first light source and that the fluorescent light emitted by the individual fluorescent defects is detected. Furthermore, fluoresce on the surface of the solid deposited dust particles when exposed to light, the by the image processing due to another form and / or Size and / or another color of the emitted fluorescent light from the defects can be separated. Regarding the color, the fluorescent light of the dust particles in terms of hue, color intensity and / or color saturation be distinguished from the fluorescent defects.

By the separation of the dust particles from the defects can be the method according to the invention also outside a clean room, so for example in a production hall, be performed. This allows the application of the method z. B. in a production line, where then Solid, the for example, very large fluorescent defects or especially many fluorescent defects have to be singled out as a scrap.

According to one embodiment of the invention, the fluorescent defects in the solid and the fluorescent dust particles are localized on the solid. Furthermore, the number of fluorescent defects and dust particles is determined. In addition, a determination is made of the size and / or shape of each fluorescent defects and / or each Staubteilchens. By determining the size or shape of each fluorescent defect, it is very easy to separate the dust particles from the fluorescent defects. The dust particles are usually very elongated and fuzzy formed, whereas fluorescent defects, as will be explained in more detail below, are spherical. By localizing the individual defects in the solid, it is also possible to compare the distribution of defects between different solids and possibly then possible causes to find the defects in the solid during the production of solids.

To an embodiment the invention, the fluorescent light after filtering with a first Filter and without the first filter being used, after filtering detected with a second filter. The first filter has a high transmissivity for the Fluorescent light emitted by the defects and a small amount transmissivity for the fluorescent light emitted by the dust particles. The opposite the second filter has a low transmissivity for that of fluorescence emitted by the flaws and high transmittivity for that of the dust particles emitted fluorescent light. This embodiment has the advantage that the dust particles from the flaws very be simply detected by means of a first filter, the only high permeability has for the fluorescent light emitted by the defects and a low permeability for the fluorescent light emitted by the dust particles, the dust particles can be easily separated from the flaws, as far as the dust particles fluorescence light in another wavelength range as the flaws emit. This has the further advantage of that from the image processing only the dust particles by form and / or size and / or Color must be separated from the defects, the fluorescent light in the wavelength range emit in which the first filter has a high transmissivity.

To an embodiment According to the invention, the first light source emits light in the blue wavelength range and / or in the ultraviolet wavelength range. As the first light source For example, a mercury vapor lamp or a blue laser or a blue LED is used.

To an embodiment According to the invention, the first light source is light in the wavelength range emitted between 450 nm and 10 nm.

According to one embodiment of the invention, according to the method, the exposure of the solid to light from a second light source and the detection of the light transmitted through the solid when exposed to the light from the second light source and the light reflected from the solid. Subsequently, an image processing of the transmitted and detected light, whereby non-fluorescent defects are detected in the solid state. A method for detecting defects due to the detection of the transmitted light or the intensity distribution of the transmitted light and corresponding detection of the light reflected by the solid or the intensity distribution of the reflected light are in the DE 101 44 909 A1 and the DE 10 2004 054 102 A1 whose disclosure content is hereby included in the description. After that, defects in a solid, in particular in a plastic body such as a CD or DVD, can be detected by a spatially resolved measurement of the intensity of the reflected and transmitted light. Thus, optical, macroscopic errors with dimensions up to a few millimeters, such as streaks and specks, as well as opaque light-scattering defects, such as glass fiber inclusions or air pockets, can be detected. By using a combination of the method described above for the detection of fluorescent defects and the method described in this embodiment, therefore, fluorescent defects as well as non-fluorescent defects in the solid can be found in a particularly simple manner.

To an embodiment the invention, the image processing, the position, size, number and / or form any non-fluorescent defect detected in the solid state. By detecting the position of non-fluorescent defects can be determined by comparing the detected positions for the fluorescent Defects, for example, are examined for an association between the fluorescent and the non-fluorescent defects consists. This may possibly a better understanding for the Production process of the solid be won. This understanding can then be used to improve the production process and the number of fluorescent and / or non-fluorescent defects in the solid state minimize.

To an embodiment the invention is in the solid state to a plastic body or a plastic film.

According to one embodiment of the invention, the fluorescent defects are gel bodies in the plastic body. Furthermore, the non-fluorescent defects are streaks, specks, glass fibers or air pockets in the plastic body. Gel bodies are defects in the plastic body, which are usually already in the plastic granules from which the plastic body is made available. On an industrial scale plastic bodies are typically produced by injection molding of plastic granules. The gel bodies present in the granules can lead to flow defects in the finished injection-molded part, that is to say in the plastic body, which are also referred to as streaks. Streaks are particularly undesirable in plastic bodies because these streaks are elongated, relatively large defects. Specks are spherical, macroscopic optical defects caused by burning of the plastic, e.g. B. during the granulate-Her position, arise. Therefore, specks are already present in the plastic granules. Glass fibers and air bubbles are usually caused by the injection molding process in plastic bodies, but are much less relevant than those mentioned above.

To an embodiment becomes the solid with the light of the first light source and with the light of the second Light source applied in regions or in rows. After this embodiment becomes the solid not lit as a whole, but with the light of the first Light source or with the light of the second light source partially scanned. This has the advantage that significantly less powerful light sources can be used because smaller areas of the solid be lit up. An entire picture of the solid or the fluorescent defects can then be determined by means of image processing create.

To an embodiment The invention further takes the removal of a sample from a Kunststoffgranulatcharge. The plastic granulate batch is plastic granules which are in a process and therefore using the same process parameters has been produced. From the sample, a solid is produced, in particular in an injection molding process. Furthermore, the determination of the fluorescent and / or non-fluorescent Defects and based on the determined fluorescent and / or non-fluorescent defects, whether the solid body at least a predetermined quality criterion Fulfills. The plastic granulate batch is only released if the solid body meets at least one quality criterion.

According to the invention a quality control the Kunststoffgranulatcharge by the production of a plastic body the sample taken from the granules. The granules are only released if it has been determined from the defects in the plastic body, whether the plastic body the predetermined quality criterion Fulfills. The plastic body thus serves as a candidate, which is produced on a trial basis from the granules. Is that granules z. For example the preparation of CD substrates provided so are the test specimen the for CD substrates required quality criteria created. Only if the examinee these quality criteria Fulfills, It is assumed that the granules are suitable for this Produce CD substrates. Accordingly, another predetermined quality criterion to the examinee created when from the corresponding granule batch motor vehicle headlight covers should be produced, as in this case more generous criteria to the quality can be made. It is crucial that defects that are already in the plastic granules are present, on the one hand, the quality of the plastic granules manufactured plastic body can reduce and on the other hand also be the cause of further defects in the plastic body can. As mentioned above, are gel bodies and specks already present in the plastic granules. especially the gel body to lead to flow disturbances, which are caused by the fact that a gel body during casting of the Plastic body in the injection molding process a certain distance in the direction of flow is pulled. The flow disturbances, which are also known as streaks, therefore always have one gel body up and are elongated in the direction of the flow direction oriented.

The Process has the advantage that by producing one Plastic body, which serves as a test specimen, the quality of for the production of the plastic body used granules for defects is checked. Already can before the delivery of the granules to a customer or before use of granules for the production of plastic bodies in mass production be determined whether the granules for the intended plastic body as Raw material at all suitable is. Unsuitable granules do not even begin to be produced of plastic bodies used or delivered to the customer. That causes the committee on unusable plastic bodies is reduced, which leads to a reduction in production costs. moreover Customer complaints will be less frequent as only high quality Granules are shipped, which of course leads to an image improvement the granulate manufacturer opposite leads to his customer.

According to one embodiment of the invention, the solid body is produced in an injection molding machine and is disc-shaped or plate-shaped. The production of the plastic body in an injection molding machine has the advantage that it produces a transparent plastic body in the same manner as usually also plastic bodies are produced on an industrial scale. Thus, a test specimen is produced, which has similar production-related defects due to the same manufacturing method as in mass production. A plastic body produced in this way is therefore particularly well suited for deciding on the basis of whether the granulate used for the production meets the specified quality criterion. In this case, the plastic body is plate-shaped or disc-shaped. On the one hand, a plate-shaped or disc-shaped plastic body can be produced in an injection molding machine in a particularly simple manner and, on the other hand, plate-shaped or disc-shaped plastic bodies can be examined particularly well by means of optical test methods. Furthermore arise in the The main point of failure in plastic bodies by the casting process in the injection molding machine, in particular by the contact with the forming tool surface of the injection mold. The geometry of the shaping tool surface is secondary. The use of plastic plates as a particular embodiment of an injection mold geometry for determining whether a granulate meets a predetermined quality criterion is therefore completely sufficient. The plastic body is produced by means of a film gate system after previous screw plasticization of the granules in the injection molding machine. The screw plasticization of the granules is carried out with flow-cut injection molding screws. The injection-molding screw and injection-molding cylinders have deposit-resistant surface coatings and / or consist of alloys containing high chromium. As a particular embodiment, the injection molding machine is equipped with on-line process data acquisition. Process data acquisition ensures that melt and mold temperatures are within a suitable temperature range for the material. Furthermore, thermal decomposition and / or crosslinking processes which can cause defects are avoided. Other relevant process parameters that are controlled by the process data acquisition include the cycle time, any possible cavitation counteracting pressures, as well as the injection rate of the liquid sample into the tool. The cycle time determines the residence time of the plastic in the machine. The injection rate is critical to the shear rate that occurs and thus the resulting shear stress of the melt. The sprue is centered eccentrically on a straight cold channel with film gate. The sprue is advantageously carried out centrally eccentrically to avoid flow deflections and the material deposits thereby required in the field of flow deflections. Advantageously, after the production and the stamping of the sprue, the plastic body passes through a cooling section, which leads to a homogeneous cooling of the test specimen. After the mold has cooled, it is removed by a suitable gripper system without touching the surface of the plate. A preferred embodiment of a gripper system is a lateral gripper that only contacts the plate edges.

To an embodiment The invention is at least one surface side of the solid with deionizing air blown before the solid with Light of the first or second light source is applied. By the deionizing air will be the at least one surface side electrically discharged. Dust particles are from the surface side away. In addition, the attraction of the now discharged surface side reduced to dust particles. That has the advantage of being far less Dust particles on the surface are present when the plastic body by means of the above-described optical test method checked for defects.

To an embodiment The invention becomes a surface of the plastic body subjected to light, wherein a projection surface of the fluorescent and / or the non-fluorescent defects is determined, the quality criterion a maximum projection area specified and wherein a release of the plastic granulate batch only takes place when the projection surface the fluorescent and / or the non-fluorescent defects smaller than the maximum projection area. Through the image processing can the total area, the the fluorescent and / or non-fluorescent defects in terms of the projection surface of the entire plastic body takes to be determined. The quality criterion can now be a maximum allowed projection surface with respect to the total projection area of the plastic body. The advantage of this is that only the total projection area of the fluorescent and / or non-fluorescent defects, not but the projection screens the individual defects to determine whether the plastic body the quality criterion Fulfills, is used. The integral projection surface of the defects is included much easier to determine than z. B. the projection screen everyone single flaw.

To an embodiment According to the invention, the quality criterion specifies a minimum distance between two defects or a maximum allowable size of each of the detected defects or a maximum number of defects.

To an embodiment the invention, the plastic granulate is in one of several quality classes categorized, being for every quality class at least one quality criterion is predetermined and whereby the Granulatcharge for the highest quality class of several quality classes is released for the solid the corresponding quality criterion still fulfilled.

For example, a quality class may relate to granules for the production of CD or DVD substrates. On the plastic body, which is made from the granule sample, very high quality requirements would be made. If the plastic body does not meet the specified quality criterion, then the corresponding granule batch is not released for the production of CD or DVD substrates. However, the plastic body can meet the quality criteria, the z. B. ge to a motor vehicle headlight cover be presented. In that case, the substrate would then be released for this use. The categorization of the granule batch therefore has the advantage that the granules to be tested can be divided into several quality classes and then delivered to a customer who sets the quality requirements of the quality of the granules in terms of quality.

In In another aspect, the invention relates to a device for Detection of defects in a transparent solid with Means for impinging the solid with light from a first Light source and means for detecting the upon exposure of the solid fluorescent light generated by the light. The device also has Means for image processing the fluorescent light, wherein on the solid deposited dust particles due to their shape and / or size and / or the color of the emitted fluorescent light from the fluorescent Defects are distinguished.

in the Other preferred embodiments the invention with reference to the drawings explained in more detail. It demonstrate:

1 a block diagram of a device for detecting defects in a solid,

2 a flow chart showing essential steps of the method according to the invention,

3 FIG. 2 schematically the arrangement of the second light source and the means for detecting the light transmitted or reflected by the solid, FIG.

4 a block diagram of a device for the quality control of a granule batch,

5 a flowchart that represents the process for determining whether a plastic granulate batch meets a predetermined quality criterion, and

6 a table, in the type, size and shape of defects in a plastic body are specified in more detail.

1 shows a block diagram of a device 100 for the detection of defects in a transparent solid. The device 100 has an optical test unit 102 and a computer system 104 on. The optical test unit 102 has a first light source 106 and a camera 108 , Furthermore, the optical test unit 102 a lens 110 and a filter 112 on. The computer system 104 has a microprocessor 114 , a store 116 , a camera interface 118 and a screen 120 on.

The camera 108 is about a connection 122 to the camera interface 118 connected, so that from the camera 108 captured images on the computer system 104 are transferable.

A solid 124 is used to inspect for defects in the optical inspection unit 102 brought in. That from the first light source 106 generated light is transmitted through the lens 110 to one area 126 of the solid 124 displayed. The wavelength of the first light source 106 generated light is chosen so that fluorescent defects, such as the defects 130 . 132 . 134 so that they are excitable so that they glow with the emission of fluorescent light. For example, it may be in the solid state 124 to trade a plastic body. At the defects 130 . 132 and 134 they can then be gel bodies that glow in the green wavelength range when excited by UV light or blue light. For the investigation of plastic bodies on fluorescent defects can therefore z. As a mercury vapor lamp or a blue laser as the first light source 106 be used.

The camera 108 may be in relation to the first light source 106 behind the solid 128 are as in 1 shown. The filter 112 then has a high transparency for the emitted fluorescent light from that in the first area 126 illuminated defect 132 is emitted. Further, the filter faces 112 a low transparency for that of the first light source 106 generated light. This can be an illustration of the defect 132 from the camera 108 essentially without interference from that from the first light source 106 emitted light can be recorded.

The solid 124 is along the y-axis (see coordinate system 128 ) displaceable. The light source camera system consisting of the first light source 106 , the lens 110 , the filter 112 and the camera 108 , can be in the x-axis (see coordinate system 128 ) Move so that the area 126 over the entire solid 124 migrates and also the fluorescent light from the defects 130 and 134 can be included.

Furthermore, dust particles such as dust particles fluoresce 136 and 138 on the solid 124 are attached. The fluorescent dust particles can also be removed from the camera 108 be recorded. Here is the filter 112 designed so that the fluorescent light of the dust particles can pass through this.

That from the camera 108 in that area 126 captured image can be over the connection 122 and the interface 118 fed to the computer become. The microprocessor 114 Run a computer program product 140 for image processing. The computer program product 140 is permanently on the memory 116 stored and is before its execution in the microprocessor 114 been loaded.

The computer program product 140 put that of the over the solid 124 wandering area 126 made pictures to a picture 142 of the solid 124 together, that on the screen 120 will be shown.

Furthermore, the computer program product leads 140 an image processing on the image 142 by. This can be the dust particles 136 and 138 from the defects 130 . 132 and 134 due to their shape differ. Is it, for example, the solid state 126 around a plastic body and at the fluorescent defects 130 . 132 . 134 around gel body, so these are typically spherical. Consequently, these imperfections appear in the image 142 as circles, since the camera is the projection of the solid 124 in the xy plane. Dust particles, like the dust particles 136 and 138 , on the other hand, are rather fuzzy in shape and also larger in size than the imperfections.

The dust particles 136 and 138 usually also fluoresce with a different color than the flaws 130 . 132 and 134 , Fluorescent light of the dust particles may differ, for example, in hue and / or in the color intensity and / or in the color saturation of fluorescent light of the defects.

Therefore, dust particles and fluorescent defects can also be detected due to the different color of the fluorescent light emitted by them. For example, the camera can do this 108 be formed so that it can be made with colored images, the color resolution is sufficient to detect the color difference between defects and dust particles.

2 shows a flowchart that represents steps of the method according to the invention for the detection of defects in a solid. In step 200 the application of the solid takes place with light from a first light source. In step 202 is then detected when exposed to the solid with the light of the first light source of defects in the solid and / or dust particles that are attached to the solid, emitted fluorescent light. In step 204 the image processing of the fluorescent light takes place, whereby dust particles attached to the solid body are distinguished from the fluorescent defects due to their shape and / or size and / or the color of the emitted fluorescent light.

3 schematically shows the arrangement of a second light source 144 and from other cameras 146 . 148 and 150 for the detection of non-fluorescent defects in the optical test unit 102 , The solid is for that of the light source 144 emitted light transparent.

With the light source 144 becomes a second area 152 of the solid 124 illuminated. The light source camera system consisting of the light source 144 and the cameras 146 . 148 and 150 is also along the x-axis (see 128 ) displaceable. The plastic body is slidable along the y-axis so that the area 152 over the entire solid 124 migrates and this can therefore be completely scanned.

With the camera 146 it becomes solid 124 reflected light detected, whereas with the cameras 148 and 150 the transmitted through the solid and from the defects in the plastic body 124 scattered light is detected. The camera 148 is in the bright field 144 the light source 144 and the camera 150 is in the dark field of the light source 144 , By using the spatially resolved detection signals of the cameras 146 and 150 and maybe the camera 148 let yourself, as in DE 10 2004 054 102 A1 described in detail, non-fluorescent defects in the plastic body, in particular determine their location, shape and size.

4 shows a block diagram of a device 400 for the control of the quality of a batch of granules. The device 400 has an injection molding machine 402 , a punch 404 and a cooling section 406 on. The device 400 for quality control also has funds 408 for generating deionizing air. Furthermore, the device 400 from 1 respectively. 4 known optical test unit 102 and that out 1 known computer system 104 on.

A granule batch undergoing quality control becomes a sample 416 taken and the injection molding machine 402 fed to the sample 416 a plastic body (KSK) 422 manufacture. The injection molding machine 402 has a sprue system 410 and online process data acquisition (PDE) 412 on. With process data acquisition 412 Ensures that melt and mold temperatures are within a suitable temperature range for the material and additional defects in the sample resulting from thermal decomposition or crosslinking processes 416 by means of the injection molding machine 402 avoid plastic body to be produced to become. Other relevant process parameters include the cycle time which determines the residence time of the plastic in the machine and the possible counteracting of blowholes, which are also determined by process data acquisition 412 be ensured. Furthermore, the process data acquisition regulates 412 the injection rate of the molten sample 416 into a mold cavity of the injection molding machine via the sprue system 410 , The sprue is centrally eccentrically • via a straight cold runner to avoid flow deflections and the resulting material deposits in the area of the flow deflections. The tool cavity is formed by at least two mold halves, by means of which the plastic body with wall thicknesses between 0.5 to 10 mm, preferably 1 to 4 mm and with a flow length of 50 to 700 mm, preferably 100 to 300 mm is produced.

The plastic body 422 gets out of the injection molding machine 402 For example, with a handling device, taken without the surface of the plastic body 422 is damaged. By means of the punch 404 becomes the sprue from the plastic body 422 separated. Following this, the plastic body passes through 422 the cooling section 406 ,

Before the plastic body 422 the optical test unit 102 is supplied, at least one surface side of the plastic body 422 blown with deionizing air. For this purpose, the means 408 a blower for generating deionizing air 414 on. The surface to be blown on the plastic body 422 gets on the blower 414 passing by removing dust particles from the surface and discharging the surface. By discharging the surface, new dust particles become much smaller than before from the plastic body 422 dressed.

Following this, the plastic body 422 the optical test unit 102 fed. When loading the plastic body 422 with the light from the first light source 106 fluoresce defects in the plastic body, as far as available and as far as they can fluoresce. In the case of the fluorescent defects in the plastic body 422 these are, in particular, gel bodies which as a rule are already present in the granules. The gel bodies occur as defects in the plastic body. However, they can also cause elongated flow disturbances, the so-called streaks. Streaks always run approximately directly (+/- 15 °) in the flow direction of the sprue in the injection molding machine 402 , Streaks arise when a gel body is pulled during the casting of the plastic body over a certain distance in the flow direction. Therefore, streaks always have a gel body. Furthermore, dust particles fluoresce upon exposure to the light from the first light source 106 , However, the number of dust particles should be minimized due to the use of deionizing air. This ensures that all defects in the plastic body are detected, because it is almost certain that no defects are covered by a dust particle.

The camera 108 serves to receive an image of the plastic body 116 with fluorescent defects and with fluorescent dust particles. The camera signal is transmitted to the computer system via the camera interface (not shown here) 104 fed.

The computer program product 140 has an image processing component 420 on. With the image processing component 420 may be the fluorescent defects and dust particles in the plastic body 422 or in the camera 108 obtained image of the plastic body detected and distinguished from each other. Furthermore, with the image processing component 420 the size and shape of each fluorescent defect can be determined. Furthermore, the image processing component allows 420 the determination of the number of fluorescent defects in the plastic body 422 ,

In the computer program product 140 is also a quality criterion 418 implemented. The computer program product 140 determined by means of the image processing component 420 found fluorescent defects, whether the plastic body 422 the given quality criterion 418 Fulfills. The quality criterion 418 can z. B. require that no fluorescent flaw may be present in the plastic body with a size over 100 microns ² . In the event that by means of the image processing component 420 a defect is detected which is greater than 100 microns ² , there is no release of the granule batch. This can be done by making the computer program product 140 over the screen 120 (see. 1 ) a corresponding message to the operator of the device 400 outputs. In the event that no defect greater than 100 microns ^{2 is} found, the release of the granule batch, z. B. by the computer program product 140 sends a message to the operating personnel.

Furthermore, the non-fluorescent defects in the plastic body 422 , such as streaks, specks and glass fibers are detected. For this purpose, the optical test unit 102 , as in 3 described, nor the second light source 144 and the cameras 146 . 148 and 150 on. The second light source 144 emits light in the visible wavelength range and the intensity of the reflected light transmitted or transmitted light is spatially resolved by the cameras 146 . 148 respectively. 150 detected. From the intensity distribution of the reflected or transmitted light can then, as in DE 10 2004 054 102 A1 or DE 101 44 909 A1 described size, location and shape of each detected non-fluorescent flaw are determined. The information obtained in this way can then be matched with one or more quality criteria defined with respect to the non-fluorescent imperfections, which determines the release of the granule batch.

5 shows a flowchart illustrating steps of the method according to the invention. In step 500 the removal of a sample from a granule batch takes place. In step 502 a transparent plastic body is made from the sample. In step 504 the transparent plastic body is examined for fluorescent defects and possibly also for non-fluorescent defects. In step 506 is determined based on the defects, whether the plastic body meets a predetermined quality criterion. If this is the case, proceed to step 508 the release of the granule batch, z. As for use for the production of plastic bodies that must meet the above quality criterion. If in step 506 it is determined that the plastic body does not meet the quality criterion, takes place in step 510 a classification of granule quality as insufficient for the quality criterion and accordingly the granule batch is not released.

6 shows a table in which defects occurring in the plastic body are classified. The streaks are, as already mentioned, flow disturbances, which are caused by the fact that a gel body during the casting of the plastic body in the injection molded body is pulled over a certain distance in the flow direction. The streaks always have a gel body and are oriented longitudinally in the direction of flow. The width of the streaks varies between 10 and 200 microns. The length of the streaks in the flow direction is usually between 0.2 and up to 10 mm.

Gel bodies are inclusions of gel material which has different optical properties than the plastic body and which fluoresce upon irradiation with UV light or with light in the blue wavelength range. The size of the gel body is about 200 to 300 microns ² . The cross-sectional area of the gel bodies is oval-shaped.

dip are spherical, macroscopic optical defects caused by burning of the plastic, z. B. in the production of granules arise. Specks have one Diameter between 5 and 300 μm.

Glass fibers and air bubbles can also occur in plastic bodies, but are much less relevant than the aforementioned. Glass fibers have a size between 10 and 300 microns ² and are cylindrical. Air bubbles are oval-shaped and have a cross-sectional area of 20 to 500 microns ² .

100

contraption

102

optical test unit

104

computer system

106

first light source

108

camera

110

lens

112

filter

114

microprocessor

116

Storage

118

Camera Interface

120

screen

122

connection

124

solid

126

Area

128

coordinate system

130

void

132

void

134

void

136

dust particles

138

dust particles

140

A computer program product

142

image

144

second light source

146

camera

148

camera

150

camera

152

second Area

400

contraption for quality control

402

Molding Machine

404

punch

406

cooling section

408

medium for generating deionizing air

410

Gate system

412

Process data acquisition

414

fan

416

sample

418

quality criterion

420

Image processing component

422

Plastic body

Claims (29)

Method for detecting defects in a transparent solid ( 124 ) comprising the steps of: - applying light from a first light source to the solid ( 106 ); - Detection of the fluorescent light generated upon exposure of the solid to the light; - Image processing of the fluorescent light, wherein attached to the solid dust particles ( 136 . 138 ) due to their shape and / or size and / or the color of the emitted fluorescent light from the fluorescent defects ( 130 . 132 . 134 ). The method of claim 1, wherein the fluorescent Defects in the solid state and the fluorescent dust particles located on the solid be, the size and / or Shape and / or color of each fluorescent defect and / or each Dust particle is determined. The method of claim 1 or 2, wherein the fluorescent light after filtering with a first filter and without the first one Filter is used, after filtering is detected with a second filter, wherein the first filter has a high transmissivity for that emitted by the defects Fluorescent light and a low transmissivity for that of the dust particles having emitted fluorescent light, wherein the second filter a low transmissivity for that of fluorescence emitted by the flaws and high transmittivity for that of Having the dust particles emitted fluorescent light. Method according to one of the preceding claims, wherein the number of fluorescent defects and / or the dust particles is determined. Method according to one of the preceding claims, wherein the first light source ( 106 ) Generates light in the blue wavelength range and / or in the ultraviolet wavelength range (UV light). Method according to one of the preceding claims, further comprising the steps of: - impinging the solid with light from a second light source ( 144 ); - Detecting the light when exposed to the light of the second light source through the solid and the light reflected from the solid state light; - Image processing of the transmitted and detected light, whereby non-fluorescent defects are detected in the solid state. The method of claim 6, wherein the image processing the position and / or size and / or Form of each non-fluorescent defect detected in the solid state is detected, with the number of fluorescent defects detected becomes. Method according to one of the preceding claims, wherein it is the solid state around a plastic body or a plastic film. The method of claim 8, wherein the fluorescent defects around gel body in the plastic body is. The method of claim 8, wherein the non-fluorescent defects around streaks, specks, glass fibers or air pockets in the plastic body is. Method according to one of the preceding claims, wherein the solid state with the light of the first light source or with the light of the second light source regionally applied or line by line. Method according to one of the preceding claims, further comprising the steps of: - taking a sample ( 416 ) from a Kunststoffgranulatcharge; Preparation of the solid ( 422 ) from the sample; Determination on the basis of the fluorescent and / or non-fluorescent defects, whether the solid has at least one predetermined quality criterion ( 418 ) Fulfills; - Release the Kunststoffgranulatcharge if the solid meets the at least one quality criterion. The method of claim 12, wherein the solid state is in an injection molding machine ( 402 ) Is produced and wherein the solid disk-shaped or plate-shaped. The method of claim 12 or 13, wherein at least a surface side of the solid with deionizing air is blown before the solid with Light of the first or second light source is applied. The method of claim 12, 13 or 14, wherein the at least one quality criterion a minimum distance between two defects, a maximum size of each the detected defects or a maximum number of defects specified. A method according to any one of claims 12 to 15, wherein a projection surface of the detected fluorescent and / or non-fluorescent defects being, being the quality criterion a maximum projection area specified, with a release of the plastic granulate batch only takes place when the projection surface the fluorescent and / or the non-fluorescent defects smaller than the maximum projection area. The method of any one of preceding claims 12 to 16, further comprising the step of categorizing the plastic granule batch into one of several quality classes, wherein for each quality At least one quality criterion is predetermined and the granule batch is released for the highest quality class of the several quality classes for which the solid still fulfills the corresponding quality criterion. Device for detecting defects in a transparent solid, comprising: - means for applying light to a solid from a first light source ( 106 ); - means for detecting the fluorescence light generated upon exposure of the solid to the light; - means for image processing of the fluorescent light, wherein attached to the solid dust particles ( 136 . 138 ) due to their shape and / or size and / or the color of the emitted fluorescent light from the fluorescent defects ( 130 . 132 . 134 ). The device of claim 18, further comprising: - funds for the localization of fluorescent defects in the solid state and the fluorescent dust particles on the solid; - funds for the determination of Size and / or Shape and / or the color of the fluorescent defects and / or the dust particles; - funds to determine the number of fluorescent defects. Apparatus according to claim 18 or 19, further comprising a first and second filter, wherein the fluorescent light after Filtering with the first filter and without the first filter is used, after filtering with the second filter detectable is, wherein the first filter has a high transmissivity for that of fluorescence emitted by the flaws and a low transmissivity to that of having the dust particles emitted fluorescent light, wherein the second filter a low transmissivity for the emitted from the defects Fluorescent light and high transmittivity for that of the dust particles having emitted fluorescent light. Device according to one of the preceding claims 18 to 20, wherein the first light source for generating light in the blue Wavelength range and / or in the ultraviolet wavelength range (UV light) is trained. Device according to one of the preceding claims 18 to 21, further with: - funds for impinging the solid with light from a second light source; - Means for detecting the upon exposure to the light of the second light source through the solid transmitted light and the light reflected from the solid; - funds for image processing of the transmitted and detected light, whereby non-fluorescent defects are detected in the solid state. Apparatus according to claim 22, wherein the image processing the position and / or size and / or Form of any non-fluorescent defect detectable in the solid state is and where the number of non-fluorescent defects is detectable. The device of claim 23, wherein the solid comprises Plastic body is, with the non-fluorescent defects around Streaks, specks, glass fibers or air bubbles in the plastic body is and wherein the fluorescent defects are gel bodies. Device according to one of the preceding claims 18 to 24, where the solid with the light of the first light source and with the light of the second Light source region by area or line by line can be acted upon. Device according to one of the preceding claims 18 to 25, further comprising: - funds for the production of the solid from a sample, the sample being taken from a plastic granulate has been; - funds for determination based on the fluorescent and / or non-fluorescent Defects, whether the solid state meets at least one predetermined quality criterion; - funds to release the plastic granulate batch, if the solid body at least one quality criterion Fulfills. Apparatus according to claim 26, further comprising an injection molding machine, being the solid can be produced in the injection molding machine. Apparatus according to claim 26 or 27, further comprising Means for blowing at least one surface side of the solid with deionizing air. Device according to one of the preceding claims 26 to 28, further comprising means for categorizing the plastic granule batch in one of several quality classes, being for every quality class at least one quality criterion is predetermined and whereby the Granulatcharge for the highest quality class of several quality classes is released for the solid the corresponding quality criterion still fulfilled.