Method and device for detecting product defects in glass panes

Abstract

The invention relates to a method for inspecting glass panes (1), in which a glass pane (1) is provided and examined for the presence of particles (3) which are embedded in the glass and have a diameter of less than 10 μm, wherein - the glass pane (1) is irradiated by means of an X-ray source (5) which has has a source spot (7) with a lateral dimension in at least one direction of at most 10 μm, - the X-ray radiation transmitted through the glass pane (1) is collected on a detector screen (9) and an image (11) of the intensity of the X-ray radiation transmitted through the glass pane (1) is generated from the X-ray intensity signals of the detector screen (9), - the glass pane (1) and the source spot (7) are moved relative to each other such that, by means of the measuring process, a region of the glass pane (1) is detected which is overall larger than a section (13) detected on the detector screen (9), and - a particle which is embedded in the glass of the glass pane (1) and has a higher density than the glass is detected as an intensity fluctuation in the image (11).

Description

[0001] SCHOTT AG 1 16.09.2025

[0002] P06232 WO

[0003] Method and device for detecting product defects in glass panes

[0004] Description

[0005] Field and background of the invention

[0006] The invention relates generally to glass manufacturing. In particular, the invention relates to quality control of thin glass using radiation.

[0007] The high temperatures during glass melting and processing can lead to corrosion of the melting tank and the associated piping and forming systems. This is particularly true for fully or partially electrically heated melting tanks, where the glass is heated directly—that is, where current from electrodes immersed in the glass is passed directly through the molten glass. In these cases, corrosion, current spikes, and other processes can cause the detachment of platinum, as well as other components, from the walls of the glass contact materials. These components accumulate in the glass and cause defects. For example, detachment of wall material can occur in piping systems made of platinum components, such as pipes, refining tubes / chambers, stirring crucibles, and drawing tanks and their nozzles. Such glass defects can be especially critical in flexible thin glass, leading to immediate or premature breakage under bending stress.This is the case, for example, when using thin glass for folding displays, where the glass is bent, particularly in so-called folding zones. Platinum particles also pose problems here; however, these particles are sometimes only a few micrometers in size and therefore difficult to detect with the human eye or automatically. Distinguishing them clearly from dust particles on the glass surface is particularly challenging and complicates optically based evaluation methods using light from the visible spectrum. This presents an additional problem, especially with ultrathin glass or in the near-surface area of ​​thicker glass, as the small thickness makes it difficult to optically differentiate between surface contaminants and glass defects within the volume. SCHOTT AG 2 16.09.2025.

[0008] P06232 WO

[0009] In mass production, glass panes with detected defects are, in the simplest case, sorted out. However, due to the aforementioned imperfect differentiation from, for example, dust particles, this can lead to an excessively high reject rate in the worst-case scenario. Alternatively, panes must be inspected and selected in a time-consuming and labor-intensive process, which can be very time-consuming and labor-intensive. An automated, high-throughput analysis process, ideally integrated into the production line, would therefore be highly desirable. Furthermore, the thinness of the material and its resulting flexibility pose additional challenges for ultrathin glass. This often pushes optical measurement methods with a shallow depth of field to their limits, as the material tends to wrinkle and is sometimes difficult to lay flat and without gradients (a few micrometers per mm) on a measuring table.Accordingly, optical measuring systems that depend on a stable focus position are subject to measurement errors, or the measuring process becomes more complicated due to complex focus tracking.

[0010] Another problem is that platinum particles or other material deposits in the glass can be concealed by overlying dust particles or other contaminants and therefore cannot be detected from above. Optimal inspection using existing methods is therefore currently only conceivable in a cleanroom and with extensive cleaning of the glass.

[0011] Object of the invention

[0012] The invention is therefore based on the objective of providing a detection method for inclusions, in particular heavy metal particles, in ultrathin glass that is as independent as possible of interfering factors such as focus position, dust or other particle load on the glass surface and that allows for fast and reliable defect detection and classification. The method should also be suitable for the detection of both surface defects and so-called "bulk" defects, i.e., inclusions. The measurement resolution should be suitable not only for larger particles of, for example, 50 pm, but also for microparticles with sizes of < 10 pm or even < 1 pm. This objective is achieved by the subject matter of the independent claims. Advantageous embodiments of the invention are specified in the dependent claims. SCHOTT AG 3 16.09.2025

[0013] P06232 WO

[0014] Summary of the invention

[0015] Accordingly, the invention provides a method for inspecting glass panes, in which a glass pane, preferably with a thickness of up to 10 millimeters, preferably a thin glass pane, in particular a thin glass pane with a thickness of at most 400 pm, is provided and examined for the presence of particles embedded in the glass with a lateral dimension of less than 50 pm, preferably less than 10 pm, wherein

[0016] - the glass plate is illuminated with an X-ray source which has a source spot with a diameter of no more than 10 pm, and

[0017] - the X-ray radiation transmitted through the glass pane is captured on a detector screen and an image of the signal, or the intensity of the X-ray radiation transmitted through the glass pane, is generated from the X-ray intensity signals of the detector screen, whereby

[0018] - the glass pane and the source spot are moved relative to each other, so that the measurement captures an area of ​​the glass pane which is larger overall than a section captured on the detector screen, and wherein

[0019] - a particle embedded in the glass of the glass pane with a higher density than that of the glass is detected as an intensity fluctuation or change in intensity in the image.

[0020] The image of the X-ray inspection, or rather the intensity of the transmitted X-ray radiation, is not necessarily to be understood literally as an image viewable on a display, but more generally as a data set with an assignment of intensity values ​​to two-dimensional spatial coordinates, i.e., as a two-dimensional data set. Furthermore, the source spot may not have a perfectly circular shape. For example, the source spot could be more or less elliptical. In such a case, the mean diameter is to be understood as the diameter. For an elliptical source spot, the average of the length and width dimensions can be used as the diameter. The intensity distribution of the source spot may also have a non-sharp edge. For the diameter, the diameter at half the maximum intensity, or the full width at half maximum (FWHM), is used. SCHOTT AG 4 16.09.2025

[0021] P06232 WO

[0022] A device for X-ray inspection of glass panes according to this disclosure comprises accordingly

[0023] - an X-ray source which has a source spot with a diameter of at most 10 pm,

[0024] - a detector screen spaced away from the X-ray source, as well as

[0025] - a device for storing or guiding a glass pane such that the glass pane can be arranged between the source spot of the X-ray source and the detector screen, and that the distance of the source spot of the X-ray source to the glass pane is less than the distance of the glass pane to the detector screen, so that

[0026] - the X-ray radiation transmitted through the glass pane can be captured on the detector screen in order to generate an image of the X-ray transmission of the glass pane, or of the intensity of the transmitted X-ray radiation, from the X-ray intensity signals of the detector screen, and wherein the image of the intensity is preferably magnified on the detector screen compared to the section of the glass pane captured by the detector screen, and

[0027] - a particle embedded in the glass of the glass pane with a higher density than the glass can be detected as an intensity fluctuation in the image or on the detector screen, and wherein the device further

[0028] - includes a device for moving the glass disk relative to the X-ray source, so that the measurement captures an area of ​​the glass disk which is larger overall than a section captured on the detector screen.

[0029] The method and apparatus enable the detection of small particles in glass panes with thicknesses of up to 10 mm and more. As mentioned, the method is particularly suitable for thin and very thin glass. Preferably, the glass thickness is at most 10 mm, and more preferably, for a thin glass pane, at most 400 pm. The inspection of thin glass panes with thicknesses of at most 100 pm is another preferred embodiment of the invention. In thin glass, the X-ray absorption in the glass is low, and therefore the contrast of the X-ray signal from embedded particles, especially particles containing heavy metals such as platinum particles, is correspondingly greater. SCHOTT AG 5 16.09.2025

[0030] P06232 WO

[0031] Compared to optical methods, X-ray examination has proven to be significantly more sensitive in distinguishing heavy metal particles from surface contaminants such as dust deposits. This is primarily due to the very high depth of field of the X-ray array, resulting in imaging that is largely independent of position, and the very high contrast due to the strong X-ray absorption of heavy metals, particularly platinum particles. Additionally, the particles can also exhibit X-ray diffraction or scattering effects due to their embedding in the glass. Diffraction can be caused by interface effects and material variations. The detection of such platinum particles constitutes the main application of the method and the apparatus according to this disclosure.According to a preferred embodiment, the method therefore comprises the detection of platinum-containing particles embedded in the glass, in particular metallic platinum particles or platinum-containing particles. The method and the device enable reliable high-throughput measurement, even with increasing format sizes, and are thus correspondingly scalable. Furthermore, the device and the method achievable with it can be easily integrated into automated operation, including online or inline operation, such as in ongoing glass ribbon production. Handling and / or follow-up inspection by human operators can be reduced to a minimum. In addition, automatic classification of the detected defects is possible. Since platinum is one of the densest materials, corresponding particles can be very well visualized solely by their X-ray absorption.Furthermore, other particles, such as dust particles or other organic and / or inorganic deposits on the glass, are more or less invisible in the X-ray image, since the density of dust is usually lower than that of the glass pane. This results in a very good signal-to-noise ratio, which significantly simplifies automated evaluation and classification using image analysis software. Other contaminants, such as zirconium oxide, tin, molybdenum, or rhodium, can also be detected. However, the density difference between these particles and the glass is not as high as that of platinum.

[0032] Due to the small size of the swelling spot, the detection of small glass defects is also facilitated, especially when these, as with platinum particles, pose a significant risk. SCHOTT AG 6 16.09.2025

[0033] P06232 WO exhibits modified X-ray absorption. Detection of such small defects in the micrometer range or below is further improved when the distance of the X-ray source spot to the glass plate is less than the distance of the glass plate to the detector screen, so that the image on the detector screen is magnified compared to the area of ​​the glass plate captured by the detector screen.In a device suitable for carrying out the method, it is therefore preferably provided that the glass pane can be arranged between the source spot of the X-ray source and the detector screen using the device for storing or guiding a thin glass pane in such a way that the distance of the source spot of the X-ray source to the glass pane is less than the distance of the glass pane to the detector screen, so that the image of the X-ray absorption on the detector screen is magnified compared to the section of the glass pane detected by the detector screen.

[0034] Suitable X-ray sources capable of generating a source spot diameter of 10 pm or less are supplied, for example, by Hamamatsu Photonics. X-ray sources designated L9181-02, L9421-02, L10101, L10101, L10321, or L12161-07 achieve a source spot diameter of 5 pm at an X-ray power of 4 W. The LI 0711-03 X-ray source can even achieve a source spot size of 0.25 pm. The beam angle of these sources is at least 39°, which allows for illumination of a large detector screen even at close proximity to the source. With the LI 0711-03 X-ray source, which produces a source spot size in the nanometer range, the beam angle is even 140°. Another so-called nanofocus X-ray source, which has a source spot size with a diameter below 1 pm, is the NanoTube N3 from Excillum AB, Sweden.This source achieves a resolution of 150 nm with a minimum distance of 150 pm between the source spot and the object and an X-ray power of 3.6 W. The listed sources can be mounted in any orientation to create a horizontal, vertical, or angled fluoroscopy path consisting of the source, glass, and detector.

[0035] The invention is explained in more detail below with reference to the drawings. In the drawings, identical reference numerals denote identical or corresponding elements. SCHOTT AG 7 16.09.2025

[0036] P06232 WO

[0037] Brief description of the characters

[0038] Fig. 1 shows a schematic device for X-ray inspection.

[0039] Fig. 2 shows a velocity-time diagram of the motion of a device for moving a glass disk relative to the X-ray source.

[0040] Fig. 3 shows measurement sections on the glass plate with a movement path to position the glass plate 1 relative to the X-ray source.

[0041] Fig. 4 shows a schematic representation of a thin glass manufacturing plant.

[0042] Fig. 5 shows a device for X-ray inspection with continuous movement.

[0043] Fig. 6 shows a device for X-ray inspection with multiple detector screens.

[0044] Fig. 7 shows a variant of the embodiment shown in Fig. 6.

[0045] Fig. 8 shows a thin-glass ribbon with several cascaded X-ray sources.

[0046] Fig. 9 shows a glass pane 1 and diagrams of its location-dependent

[0047] Ab stood in relation to the X-ray source and the magnification.

[0048] Fig. 10 schematically shows an image captured with a detector screen.

[0049] Detailed description

[0050] Figure 1 schematically shows a device 2 for the X-ray inspection of glass panes 1. The device 2 comprises an X-ray source 5, a detector screen 9, and a device 20 for supporting or guiding a glass pane 1. This device 20 can also be configured as a device 21 for moving the glass pane 1 relative to the X-ray source 5. The X-ray source 5 generates X-rays emanating from a small source spot 7. The glass pane 1 is arranged such that the X-rays enter the pane 1 through one of its side surfaces 12 and exit at the opposite side surface 10, as illustrated by two exemplary X-ray beams 15 in Figure 1.

[0051] If a particle 3 is located in the glass of the glass pane 1, which has a higher X-ray absorption than the glass itself, the shadow cast by the particle 3 on the detector screen 9 results in an intensity minimum. Such a particle 3 SCHOTT AG 8 16.09.2025

[0052] P06232 WO therefore appears as a dark spot in the image. As shown below, the pattern in the X-ray signal image can also be more complex, for example, if diffraction or scattering effects are present.

[0053] The method can also detect very small particles below 10 pm, or even those with a smallest lateral dimension below 1 pm, provided the image is magnified. For this purpose, the distance 18 from the source spot 7 to the glass plate 1 is smaller than the distance 19 from the glass plate 1 to the detector screen 9. Without being limited to specific embodiments, a preferred embodiment of the method and the device 2 provides that the distance 19 between the glass plate 1 and the detector screen 9 is at least 10 times, and preferably at least 30 times, greater than the distance 18 between the source spot 7 and the glass plate 1. For illustrative purposes, the distance to the center of the glass plate 1 is shown in Fig. 1. However, this is irrelevant in practice if the glass plate 1 is significantly thinner than the distances 18 and 19 to the source spot and the detector screen 9.Preferably the glass pane 1 has a thickness of less than 400 pm, in particular less than 300 pm, more preferably at most 100 pm.

[0054] According to an alternative or additional embodiment, the glass pane 1 is arranged, in particular by means of the device 20 for storage or guidance, between the X-ray source 5 and the detector screen 9 such that the distance of the glass pane 1 to the source spot 7 of the X-ray source 5 is in a range of about 1 to 10 millimeters and / or the distance of the glass pane 1 to the detector screen is in a range of about 10 centimeters to 100 centimeters.

[0055] The distances between the glass pane 1 and the source spot 7 and the detector screen 9 determine, among other things, the field of view detected by the detector screen 9, or rather the section of the pane that is detected. According to a further embodiment, the distances 18, 19 between the glass pane 1 and the source spot 7 and the detector screen 9, as well as the size of the detector screen 9, are selected such that a section 13 detected by the detector screen 9 on a glass pane 1 has a size of less than 10 x 10 mm. Regardless of the lateral dimensions of such sections, according to yet another embodiment, the distances 18, 19 between the glass pane 1 and the source spot 7 and the detector screen are... SCHOTT AG 9 16.09.2025

[0056] P06232 WO

[0057] 9, and the size of the detector screen 9 is chosen such that a section 13 detected by the detector screen 9 on a glass pane 1 covers an area in the range of 1 mm 2 up to 100 mm 2Depending on the desired magnification and size of the detector screen, the cutout 13 can also be larger. According to another embodiment, the detector screen 9 and the distances are selected such that a cutout with a dimension in at least one direction of up to 150 mm, preferably a cutout with dimensions of up to 150 x 150 mm, is detected by the detector screen 9.

[0058] The detector screen 9 can be square, rectangular, or oblong, configured as a one-dimensional line sensor. The side dimensions of the detector screen are preferably between 100 mm and 1000 mm. In one embodiment, the detector screen 9 has a size of 500 x 500 mm and a resolution on the order of 5000 x 5000 pixels. At a distance 18 of 10 mm and a distance 19 of 500 mm, the shadowing diameters on the detector screen 9 are as follows, according to the intercept theorem:

[0059] 10 pm particle diameter ~ 500 pm shadowing diameter ~ 4 pixels,

[0060] 5 pm particle diameter ~ 250 pm shadowing diameter ~ 2 pixels,

[0061] 1 pm particle diameter ~50 pm shadowing diameter ~1 pixel.

[0062] It is also possible to position several individual sensors next to each other to form a larger detector screen 9 and to measure a larger area.

[0063] The detector screen 9 can also be designed as a one-dimensional line sensor, in which case it comprises only one or a few pixels in the direction of movement of the glass disk and can have, for example, 5000 pixels perpendicular to the direction of movement of the glass disk. This embodiment of the detector screen is particularly suitable in conjunction with continuous relative movement of the glass disk to the source spot and a continuous X-ray source, and has the advantage that the detector complexity can be significantly reduced and even higher resolutions are possible in the lateral direction. On the other hand, a higher intensity X-ray source may be required.

[0064] In order for the image of particle 3 to be sharply focused and, in particular, for a core shadow to be retained even at greater distances to the detector screen, and for particle 3 to remain visible, it is generally particularly advantageous if SCHOTT AG 10 16.09.2025

[0065] P06232 WO

[0066] X-ray source 5 is designed such that the source spot 7 has an extent, in particular a diameter, of less than 1 pm.

[0067] With high spatial resolution and high magnification, the captured section of the glass pane 1 is, as mentioned, small, especially small compared to the dimensions of the glass pane 1, or rather its side surfaces 10, 12. However, the inspection should ideally not only be a sample, but cover a relevant part or even the entire glass pane 1.

[0068] It is generally provided that the glass disk 1 and the source spot 7 are moved relative to each other together with the detector screen 9, so that by measuring, or rather a multitude of measurements at individual sections, an area of ​​the glass disk 1 is captured which is larger overall than a section 13 captured on the detector screen 9. For this purpose, a device 21 for moving the glass disk 1 relative to the X-ray source 5 is provided. In an embodiment, which is also realized in the example of Fig. 1, the device 20 for supporting or guiding a glass disk 1 is simultaneously designed as the device 21 for moving the glass disk 1 relative to the X-ray source 5. For example, the device 21 can transport the glass disk 1 with rollers or by means of a conveyor belt. Conversely, the thin glass can also be fixed and the source spot 7 and detector 9 moved simultaneously relative to the glass.

[0069] The detector screen 9 can include an analog-to-digital conversion interface 90, or such an interface can be connected to the detector screen 9. Alternatively, single-photon-counting detector screens can be used, which directly perform a digital count of photons per pixel. Digital data acquisition enables any further processing in computer systems. In addition to storing the raw images, direct segmentation of defect sections and classification into defect types is possible. A computing unit 91 can generally be provided for further processing and evaluation of the image data. Since heavy metal particles, such as platinum particles in particular, cause a very characteristic local and sharply defined darkening in the X-ray image, reliable automated detection and classification can be carried out easily and with high accuracy using a suitably configured computing unit 91.The image analysis in the computer unit 9 requires SCHOTT AG 11 16.09.2025.

[0070] P06232 WO In the simplest case, only strong contrast fluctuations can be detected, and compared to the analysis of inspection results with visible light, it is uncomplicated because the classification and delimitation of dust and other contaminants is not necessary. Without being limited to the exemplary embodiments, a further development of the method and the device 2 therefore provides a computing unit 91 which examines the image data for local contrast changes. If such a local contrast change, in particular a local darkening, is present, the computing unit 91 can detect the presence of a particle 3. The computing unit 91 can then issue a corresponding message or signal indicating that a particle 3 has been found. With full automation, a sorting device could remove the glass pane 1 containing the particle 3 upon receiving such a signal.Otherwise, such an error message can also be used to examine the relevant glass pane 1 more closely.

[0071] Furthermore, such a signal and the corresponding positional information of the detected defect can be used to plan the post-processing of the glass pane 1. For example, the cutting of the glass pane 1 can be planned in such a way that the defect is either avoided or, if the glass pane 1 is cut into smaller tiles, the affected tile is rejected. According to a further development of the method, the glass pane 1 is cut in such a way that at least a portion of a predetermined size is obtained, and the cutting lines are positioned so that a detected particle is not contained in the portion of the predetermined size or is not located in a defined zone of the portion.

[0072] For further classification, the data can also be synchronized and compared with that of other sensors, such as optical sensors.

[0073] Due to the limitation of the image field and depending on the format size of the glass plate, the glass plate 1 can be scanned in several individual images or tiles. To achieve a sufficient exposure time, the relative movement of the glass plate 1 with respect to the X-ray source 5 can be intermittent. Fig. 2 shows an exemplary velocity-time diagram of the device 21. As shown, the glass plate 1 is moved relative to the X-ray source 5 alternately in movement-time intervals 23 and stopped in measurement-time intervals 24. Within the measurement-time intervals 24, an X-ray image can then be acquired at SCHOTT AG 12 16.09.2025

[0074] P06232 WO is recorded on a stationary glass plate 1 relative to the X-ray source 5. The movement can be along a line, so that a strip with the width of the illuminated sections is inspected. The movement can also be more general, in several directions, for example in the form of a meander, so that a wider strip is illuminated overall. Fig. 3 shows sections 13 on the glass plate with a movement path 27 along which the glass plate 1 can be positioned relative to the X-ray source 5. The movement path 27 is meandering, and in this example the glass plate 1 is scanned in rows with a width of three sections 13 minus overlap areas 26.Without limiting oneself to specific examples, one embodiment provides that sections 13 of the glass pane 1 are imaged step by step or scanned onto the detector screen 9, with the sections 13 on the glass pane 1 overlapping.

[0075] Of course, other movement patterns are also conceivable. In general, without being limited to the examples shown, one embodiment provides that the glass plate 1 and the source spot 7 are moved relative to each other such that movement time intervals 23, in which the glass plate 1 and the X-ray source 5 move relative to each other, alternate with measurement time intervals 24, in which the glass plate 1 and the X-ray source 5 are at rest relative to each other. Intermittent measurement is only one possibility. By synchronizing the detector readout, in particular the detector rows, with the movement of the glass plate 1, measurement during the movement of the glass plate is also possible. This is very advantageous for increasing the speed of the process.

[0076] The stepwise scanning can be performed with arbitrarily wide overlap areas 26 of the image sections, or sections 13, in order to avoid overlooking any defects in a possible gray zone outside the image field. According to one embodiment, in a further development, sections 13 of the glass pane 1 are progressively, or scanned, onto the detector screen 9 such that the sections 13 on the glass pane 1 overlap, and the overlap areas 26 have a width in the range of 1% to 10% of the width of the sections 13. SCHOTT AG 13 16.09.2025

[0077] P06232 WO

[0078] An overlap of more than 50% of the width of the cutouts is also possible to detect measurement errors. With an overlap of more than 50%, areas of the glass pane 1 can be measured twice, but with different areas, by the detector screen 9. An overlap of more than 75% even allows for triple validation of defects. This reduces the influence of pixel errors or measurement noise. According to a further embodiment, it is therefore provided that cutouts 13 of the glass pane 1 are projected onto the detector screen 9 step by step, or scanned, such that the cutouts 13 on the glass pane 1 overlap and the overlap areas 26 have a width of at least 50%, preferably at least 75%, of the width of the cutouts 13.

[0079] A rapid large-format / full-frame inspection of a glass pane 1 can be performed with an arrangement as shown in Fig. 1 and a scanning method as shown, for example, in Fig. 3. This is achieved by positioning the source spot 7 to within a few millimeters of the glass pane 1 and placing the detector screen 9 further away, for example, a few decimeters. This allows the X-ray conjugate to achieve high resolutions of less than 1 pm per pixel. By precisely matching the X-ray source 5 and the detector screen 9 to the glass and the defects, a very short exposure time of a few milliseconds per image can be realized. This enables scanning of the samples at very high speeds. Despite the small field of view of a few square millimeters, throughputs of a few minutes per square decimeter can thus be achieved.In general, without being limited to specific examples, a further development specifically provides that an image of a section 13 of the glass plate 1 is captured with the detector screen 9 with an exposure time of less than 200 milliseconds, preferably less than 50 milliseconds. On the other hand, the exposure time should not be too short, especially for the detection of small defects, in order to achieve a sufficiently good signal-to-noise ratio. For this purpose, multiple integration of images of the same area is also possible. According to a further development, the exposure time per image, the size of the sections 13 of the glass plate 1 projected onto the detector screen 9, and the movement of the glass plate 1 relative to the X-ray source 5 are determined as follows: SCHOTT AG 14 16.09.2025.

[0080] P06232 WO selected that the inspection is carried out at a speed of at least 10 square centimeters per minute.

[0081] The exposure time can also be longer, for example, if high sensitivity is required for the detection of small or low-contrast defects. Depending on the glass thickness or scanning speed, the exposure time can generally range from a few milliseconds to several seconds.

[0082] In principle, scanning can be performed stepwise, as described above, or continuously. For continuous movement, the image evaluation can be synchronized with the movement. According to a further development, this involves synchronizing the line-by-line readout of the detector screen, for example, using a line sensor, with the movement. If the line readout speed is twice as high as the movement speed, then, analogous to the previous explanation regarding overlap, multiple images of a defect can be captured at different detector positions. This can help avoid noise. Generally, continuous movement of the glass plate 1 can be advantageous because the process can then be integrated into an online or inline process in which a continuous thin-glass ribbon is produced.Such a continuous process can, in particular, be a drawing process, such as a down-draw process or an overflow fusion process. Accordingly, one aspect of this disclosure also provides for a glass sheet manufacturing plant, in particular a thin glass manufacturing plant, which comprises a hot-forming device for drawing a glass sheet 1 in the form of a continuous glass ribbon, in particular a thin glass ribbon, especially with a thickness of at most 400 pm, preferably at most 300 pm, as well as a device 2 for X-ray inspection of the glass ribbon.

[0083] Fig. 4 schematically shows such a glass sheet production plant 16. The glass sheet production plant 16 comprises a hot forming device 17, with which the glass strip 100 is typically drawn vertically, preferably vertically downwards, from a molten glass or a heated or softened glass preform. For this purpose, driven drawing rollers 31 can be provided, which exert a tensile force on the thin glass strip 100. Preferably, the glass strip 100 is drawn, for example via a deflection roller 30, in a horizontal direction. SCHOTT AG 15 16.09.2025

[0084] P06232 WO is deflected. The glass ribbon 100 is guided and transported by means of a transport device, which may, for example, include rollers 30 or conveyor belts. A cutting device 33 may be provided to divide the glass ribbon 100 into individual glass sheets 101. It is also possible to coil the glass ribbon 100. For inspection, the glass ribbon 100 is passed through a device 2 for X-ray inspection and examined for glass defects, in particular heavy metal inclusions, such as platinum particles, by means of this device 2. The movement of the glass sheet 1 relative to the source spot 7 is preferably effected by the feed of the glass ribbon 100 in the thin-glass production plant 16. Therefore, feed devices of the plant 16, such as the rollers 32 and / or the drawing rollers 31 in the example, can also form a device 21 for moving the glass sheet 1 relative to the X-ray source 5 of the device 2.Contrary to what is shown, the X-ray inspection device 2 can also examine the glass strip 100 before it is deflected into the horizontal position, i.e., during the vertical guidance of the strip after hot forming. Testing in the bending area during the deflection from the vertical to the horizontal orientation is also possible. Simultaneously, the test can also be performed on an artificially induced sag between two conveyor belts or shafts via guide systems positioned out of plane.

[0085] Furthermore, this embodiment is not limited to performing the inspection during a relative movement of the glass ribbon 100 to the X-ray source 5. For example, an oscillating movement of the X-ray inspection device 2 is possible, adapted to the movement of the glass ribbon 1, such that during part of a movement period, the X-ray source 5 moves together with the glass ribbon 100 and is therefore at rest relative to the glass ribbon 100. According to yet another embodiment, in which the relative movement between the glass ribbon 1 and the X-ray source does not need to be interrupted, the movement of the glass ribbon 1 relative to the X-ray source is continuous, with images being captured at regular time intervals by the detector screen (9). Several images are then summed with an offset corresponding to the direction of movement and the distance traveled, corresponding to the time intervals between successive captures.Images will be displayed in a sequence. SCHOTT AG 16 16.09.2025.

[0086] P06232 WO, images are acquired while the glass plate 1 is moving. The images can be summed with an offset along the direction of movement adapted to the speed of the relative movement. This offset ensures that the individual images are correctly aligned. In this way, images with a high signal-to-noise ratio can be generated, in which even small defects can be identified. According to one embodiment, which can also be implemented with a continuously or pulsed X-ray source, as in the example of Fig. 4, it is generally provided that the movement of the glass plate 1 relative to the X-ray source 5 is continuous, and images are acquired at regular time intervals with the detector screen 9. Several images are then summed with an offset corresponding to the direction of movement and the distance traveled, corresponding to the time intervals.In this embodiment as well, sections 13 of the glass plate 1 are progressively imaged onto the detector screen 9, with the sections 13 on the glass plate 1 overlapping. Generally, regardless of whether a pulsed or continuous X-ray source is used, the noise of the measurements can be significantly reduced by acquiring multiple images per measurement position with fixed and slightly offset measurement positions, since the defect signal becomes traceable and can thus be better distinguished from the measurement noise and pixel defects on the detector.

[0087] A laser-plasma X-ray source can also be used as a pulsed X-ray source 5. Precise laser excitation allows for the generation of very pure X-rays with a very short pulse duration, enabling excellent imaging.

[0088] Pulsed X-ray sources offer particularly great potential for achieving large / full-format inspection. The extremely short pulses allow for the generation of image sequences or videos with a high frame rate. The pulsed X-ray radiation can also be focused or controlled and expanded to achieve particularly high resolution. According to a further development of the embodiment with a preferably high-frequency pulsed X-ray source 5, the pulse frequency can be coupled with the exposure time or the scanning of the detector screen. This allows for very defined and high-resolution imaging. SCHOTT AG 17 16.09.2025

[0089] P06232 WO

[0090] Record image sequences at a high frequency.

[0091] Another principle for implementing X-ray inspection with continuous relative movement of the glass disk 1 and the X-ray source 5 is shown in the device 2 according to Fig. 5. Several rollers are symbolically provided as a device 20 for supporting or guiding the glass disk 1. These are configured to continuously convey the glass disk 1 in a direction of movement 35. The detector screen 9 is designed in a strip shape. The X-ray source 5 can be configured, as shown, to emit X-rays 15, which, through collimation, form a fan beam oriented so that, after transmission through the glass disk 1, it falls onto the detector screen 9. If intensity values ​​are continuously recorded by the detector screen 9 during the continuous movement of the glass disk 1, these values ​​can be assembled as image lines to form a two-dimensional image of the X-ray absorption.The image lines form strip-shaped sections 13 of the glass pane 1. This embodiment is generally based on the fact that, during the fluoroscopy of the glass pane 1, it is continuously moved relative to the X-ray source 5, whereby strip-shaped sections 13 of the glass pane 1 are continuously captured by the detector screen, which together form a two-dimensional image of an area that, in the direction of movement 35 of the glass pane 1, has a greater extent than the width of a strip-shaped section 13. The area 36 resulting from the arrangement in Fig. 5 is characterized as a hatched stripe on the glass pane 1.

[0092] Unlike in this example, the beam and the detector screen 9 do not need to be strip-shaped. The method can also be carried out in the same way with a matrix-shaped detector screen 9 and an X-ray source 5 illuminating this screen accordingly. In this case, the image lines of the detector screen 9 can even capture strip-shaped areas of the glass plate 1 multiple times, since these areas are imaged onto the different image lines one after the other. In this embodiment, the X-ray source can be operated continuously or in pulses. SCHOTT AG 18 16.09.2025

[0093] P06232 WO

[0094] An arrangement like the one shown in Fig. 5 can also be designed to rotate, with the X-ray source rotating around the glass disk 1 together with the detector screen, thus illuminating the glass disk 1 from different angles. Such an arrangement is similar to a computed tomography scanner. However, to enable rotation around an axis of rotation near or within the glass disk 1, correspondingly large distances to the glass disk 1 are generally required. This results in lower or no magnification and therefore lower spatial resolution. Nevertheless, such a rotatable arrangement can be advantageous, particularly as an additional detector device, for quickly inspecting glass disks 1 for defects.

[0095] One advantage of inspecting thin glass is the low scattering of X-rays due to its thinness. From a radiation protection perspective, X-ray inspection of thin glass ribbons is therefore relatively unproblematic, as only low intensities are required, resulting in very low scattered radiation that can be easily shielded. This allows for simple and effective radiation protection, particularly in online or inline inspections as shown in Fig. 4, but also in the other embodiments described here. Examples of such protection include undercuts, open lead tunnels, or similar devices used in airport baggage screening.

[0096] Even if the glass plates are very thin, it can be useful to determine not only the lateral position of a defect on a glass plate 1, but also its position in the direction of the X-ray beam from the X-ray source 5 or in a direction perpendicular to the side surfaces of the glass plate 1. In one embodiment, this can be achieved by repeatedly illuminating the glass plate 1, or positions on this glass plate 1, with X-rays at different angles to the side surfaces 10, 12. A defect present in the glass plate 1, such as a particle 3, is thus imaged and detected multiple times by X-rays illuminating the glass plate 1 at different angles to the side surfaces 10, 12. This can be done simultaneously, for example with several X-ray sources, and / or sequentially.Given known angles of the X-rays, the position of the defect in the direction perpendicular to the side surfaces 10, 12 can then be calculated from the images of the defect determined in the multiple measurements. (SCHOTT AG 19 16.09.2025)

[0097] P06232 WO

[0098] If glass pane 1 is generally free of defects, especially particles, then the vertical position would be less relevant if such a pane would be rejected anyway if a defect were present. However, it would still be possible to differentiate between a defect located within the volume of the pane and a particle lying on or adhering to a side surface 10, 12, whereby the latter particle might not necessarily lead to the rejection of the pane if the particle can be removed. One possible method for removing surface-adherent particles is etching the glass surface, a technique commonly used in thin glass production to thin the glass.

[0099] Fig. 6 shows a device 2 for X-ray inspection with several detector screens 9, 93. The glass pane 1 is illuminated by several X-ray sources 5, 50, and their X-rays 15 are directed onto detector screens 9, 93, which are arranged at different angles to the side surfaces 10, 12 of the glass pane 1. Therefore, several detector screens 9, 93 are arranged in the imaging space, viewing the glass pane 1 from different angles. This reduces the influence of measurement noise and allows particle signals to be verified at different angles. From the positions of the images of the defects, and in particular of particles 3, on the different detector screens 9, 93, the position of the defect or particle 3 in the direction perpendicular to the side surfaces 10, 12 can then be calculated.

[0100] In the example, separate X-ray sources 5, 50 with source spots 7, 70 are provided. However, it is also conceivable to provide a single X-ray source 5 with a single source spot 7. Without limiting itself to the illustrated example, a further development of a device 2 for the X-ray inspection of glass panes 1 is therefore provided, which has at least two detector screens 9, 93 positioned at different angles to the side surfaces 10, 12 of a glass pane 1 that can be arranged in the device 2. According to an embodiment also realized in the illustrated example, the detector screen or one of the detector screens 93 can be arranged obliquely to the side surfaces 10, 12 of the glass pane 1, wherein the source spot 70 of an X-ray source 50 is arranged relative to the detector screen 93 such that an X-ray beam 15, originating from the source spot 70 and incident perpendicularly on the detector screen 93, passes obliquely through the glass pane 1. [Image of a SCHOTT AG 20 16.09.2025]

[0101] P06232 WO individual defect on both detector screens is then automatically possible with the relative shift.

[0102] As explained above, it can be useful to determine the position of a defect within a glass pane 1 in the direction of the beam. The additional effort can also be particularly advantageous when several panes are inspected simultaneously. Specifically, throughput can be further increased by measuring several glass panes stacked on top of each other. According to one embodiment, this can be done in glass separator stacks, such as those found in storage or shipping boxes, to avoid additional handling of the individual panes. Paper is particularly suitable as an intermediate layer. Other suitable materials include plastics such as PET, BOPET, especially as films, or separating agents such as glass dust.The detectability of platinum particles remains intact even in a stack of, for example, 10 to 100 discs (with interlayers) with a total stack thickness of 1 cm or more; only the contrast decreases slightly, which can be compensated for with adjusted settings such as a longer exposure time. Instead of a longer exposure time, a single image can generally be taken multiple times, and the individual images can be summed or averaged to improve the contrast. Simultaneously, diffraction effects can lead to a particle signal independent of thickness.In such a measurement, the general presence of heavy metal particles, particularly platinum particles, in a stack (generally, not every disc contains a particle) can be determined. By switching to X-ray tomography, i.e., by scanning the stack laterally or at any angle, the relative position of a particle 3 within the stack can be determined, and any individual discs can then be inspected or measured. This even allows for a complete measurement of the production process. It is even conceivable that an entire shipping carton, including the outer packaging, could be tested for platinum particles using X-ray measurement. For this purpose, the packaging material can be optimized for high resolution and high contrast. This option enables further simplified and contactless handling. SCHOTT AG 21 16.09.2025.

[0103] P06232 WO

[0104] Fig. 7 shows a variant of the embodiment shown in Fig. 6.

[0105] Several glass panes 1 are stacked here with interleaving layers 40 to form a stack 38. Instead of inspecting a single glass pane 1, the entire stack 38 containing the multiple glass panes 1 can be inspected using the device 2. The interleaving layers 40 can be, for example, paper or plastic films made of PE, PET, BOPET, etc. By obliquely illuminating the stack with the X-ray source 50, not only can a defect, such as a particle 3, be detected, but its height within the stack 38 can also be measured, allowing the particle 3 to be assigned to a specific glass pane 1 within the stack 38. In the example shown, the measurement would reveal, for instance, that the bottommost glass pane 1 contains a particle 3. The method can also be performed, as shown, on a stack 38 packed in a container 42, such as a cardboard box.In some cases, immediate identification of the defective glass pane 1 may not be necessary. This could be the case, for example, if particles 3 are only very rarely present. In this case, an inspection can also be carried out with a less complex device 2, as shown in Fig. 1. Therefore, regardless of whether an X-ray inspection is performed with an arrangement of multiple detector screens 9, 93 and / or multiple X-ray sources 5, 50, one embodiment provides that a stack 38 with at least two superimposed glass panes 1 is provided and X-rayed. In this way, the superimposed glass panes 1 in the stack 38 are inspected together, or simultaneously. The intermediate layers 40 are advantageous for this embodiment, but not essential.

[0106] According to a further advantageous embodiment, blanks of one or more glass panes 1 can also be X-rayed in a stack with an X-ray source 5 such that the blanks are laminated with a film or between two films. This is particularly relevant when final products or intermediate products very close to the final product, such as a folding display, are to be analyzed. These glass panes can then be laminated in films to protect their surfaces. As described above and explained in more detail below, such films only slightly reduce the contrast, so that several laminated glass products can be X-rayed stacked without any problems. This allows SCHOTT AG 22 16.09.2025

[0107] P06232 WO

[0108] Throughput can be significantly increased, making high-resolution X-ray sources 5 and detector screens 9 economically viable.

[0109] According to a further advantageous embodiment, sections of one or more glass panes 1 in a stack can also be X-rayed with an X-ray source 5, wherein the sections in the stack are bonded with a removable adhesive. In the display glass manufacturing process, the display glass panes are typically temporarily bonded together in a stack using a removable adhesive. Within this stack, the display glass panes can be milled to a predetermined size using a CNC milling machine, and a circumferential edge can be produced for each display glass pane in the stack in a subsequent etching process. Therefore, the X-ray irradiation according to the invention can be performed particularly advantageously on the stack itself, where the glass sections are already stacked.According to a further advantageous embodiment, blanks of one or more glass sheets 1 can also be X-rayed in such a way in a stack with an X-ray source 5, wherein the blanks are joined to form a stack via an adhesive.

[0110] As described above and explained in more detail below, such intermediate layers only slightly reduce the contrast, so that several stacked glass products can easily be X-rayed. This can considerably increase the throughput, making even high-resolution X-ray sources 5 and detector screens 9 economical.

[0111] As mentioned, high magnification is advantageous for detecting small particles 3 with high resolution. This is preferably achieved by using correspondingly different distances 18, 19 between the glass disk 1 and the source spot 7 and the detector screen 9. Consequently, the sections 13 of the glass disk 1 that are detected on the detector screen 9 are also correspondingly small. As described, for example, with reference to Fig. 3, larger areas of the disk can be inspected by scanning or continuous scanning.

[0112] However, a thicker stack of glass panes 1 reduces the absorption contrast left by a heavy metallic particle, especially a platinum particle 3, in the X-ray image. This is because the path through the glass and any intermediate layers, such as sheets of paper, also leads to a SCHOTT AG 23 16.09.2025

[0113] P06232 WO

[0114] Absorption of X-rays occurs. In an example, consider a stack of ten glass plates 1, each 30 pm thick and with a density of 2.5 g / cm³. 3 and also ten layers of paper with a thickness of 540 pm and a density of 0.8 g / cm³ 3 A platinum particle with a diameter of 10 pm produces a maximum contrast of 16%. A platinum particle with a diameter of just one micrometer in this stack still causes a detectable contrast of 2%. Besides pure absorption, diffraction effects can also lead to the generation of contrast patterns. With a single glass plate 30 pm thick, the contrast is correspondingly higher. A particle with a diameter of 1 pm already produces a contrast of 25%. With a particle with a diameter of 10 pm, the contrast is even 253%.

[0115] Alternatively or additionally, it is also possible in principle to cascade the measurements, or to parallelize and thus accelerate the inspection using multiple sources and / or detector screens. By positioning several offset X-ray sources and detector screens along a longer passage, rapid inspection can be ensured, which can even cover the entire inspection area. Fig. 8 shows, as an example, a thin-glass ribbon 100 with several cascaded X-ray sources. Several X-ray sources and detector screens 9 are arranged one behind the other in the direction of movement 35 of the glass disk 1, as specifically in this case the thin-glass ribbon 100, and offset transversely or perpendicularly to the direction of movement 35.The movement of the glass pane 1 relative to the source spots 7 of the X-ray sources 5 results in strip-shaped inspection areas 28 extending along the direction of movement 35 from the sections 13 captured by the detector screens 9. Two adjacent inspection areas 28 are shown in Fig. 8. As in the example of Fig. 3, adjacent inspection areas 28 can have overlapping areas 26, which then also have the shape of strips. In one example, 10 arrangements of X-ray source 5 and detector screen 9 with an image area of ​​up to 150 mm width each, for example 100 mm width, or 20 such arrangements with an image area of ​​50 mm width each are used for the inspection of a glass pane 1, in particular a glass ribbon 100 with a width of 800 mm. These can have an overlap area with a width of 20% of the SCHOTT AG 24 16.09.2025.

[0116] P06232 WO

[0117] The width of the cutouts 13, or the strip-shaped inspection areas 28, is determined by the specific characteristics of the device. It is apparent to those skilled in the art that numerous arrangements of X-ray sources 5 and associated detector screens 9 are possible. Therefore, without limiting the example shown, a further development of the method and the device generally provides that the X-ray inspection device 2 comprises several X-ray sources 5 and detector screens 9 arranged such that, when the glass pane 1 is moved along a direction of movement 35 relative to the X-ray sources 5, the detector screens 9 detect different inspection areas 28. As explained, these inspection areas 28 can be, in particular, strip-shaped and / or overlap with other inspection areas 28. In any case, the inspection areas 28 together constitute a larger or overarching inspection area on the glass pane 1.

[0118] In cascaded X-ray systems, the radiation from the X-ray sources 5 should not cause exposure of adjacent detectors. Direct radiation can be shielded by suitable shielding 29, such as metal sheets. Scattered radiation can be filtered by anti-scatter grids in front of the detector screens 9. Generally, the X-ray wavelength can also be selected using filters.

[0119] An alternative or additional way to increase throughput is to adjust the spatial resolution to the requirements. In some cases, certain areas of the thin glass are more critical with regard to glass defects than other areas. In such a case, the measurement speed could be increased in the less critical areas at the expense of lower spatial resolution. Conversely, a particularly critical area can be examined with high resolution. An example of such a case is glass sheets 1 that have an area where bending or bending stress occurs during use, while adjacent areas are less mechanically stressed. This is the case, for example, with a glass sheet 1 that is used as the display glass of a flexible, foldable, or hinged display.The use of a glass pane 1 as the display glass of a foldable display, which can be tested or manufactured using the method and apparatus 2 or a thin glass manufacturing plant 16 according to this disclosure, is a preferred application of SCHOTT AG 25 16.09.2025.

[0120] P06232 WO

[0121] Method and apparatus 2. While minute platinum particles in the glass do not cause optical disturbances in themselves, they can, on the other hand, reduce the strength in mechanically stressed areas and thus increase the probability of breakage. Therefore, it is advantageous to examine such an area with a higher resolution than adjacent, less mechanically stressed areas. To achieve this, the magnification can be adjusted. For this purpose, the distances 18, 19 of the glass plate 1 to the source spot 7 and to the detector screen 9, as shown in Fig. 1, can be changed. It is sufficient to adjust one of these distances to change the size of the area 13 captured by the detector screen 9 and thus also the resolution. To change one or both distances 18, 19, a distance adjustment device 45 can be provided. In the example shown, the device 45 is connected to the X-ray source 5 so that the distance 18 of the glass plate 1 to the source spot 7 is adjustable.Other configurations are also possible. For example, the arrangement of X-ray source 5 and detector screen 9 can be moved relative to the glass plate 1, or conversely, the glass plate can be moved relative to the X-ray source 5 and detector screen 9, so that both distances 18, 19 change in opposite directions. Without limiting this to specific examples, a further development of the device 2 provides a device 45 for changing the position of at least one of the distances 18, 19 of the glass plate 1 to the source spot 7 of the X-ray source 5 and the detector screen 9, wherein the device 45 for changing the position is configured to change at least one of the distances 18, 19 during the inspection of the glass plate 1 in order to inspect different areas of the glass plate 1 with different resolutions.The method that can be carried out with this further development of the device 2 is accordingly based on the fact that during the inspection of the glass pane 1 at least one of the distances 18, 19 of the glass pane 1 to source spot 7 and detector screen 9 and thus the size of the section 13 of the glass pane 1 detected by the detector screen 9 is changed, so that different areas of the glass pane 1 are detected with different spatial resolution.

[0122] Fig. 9 illustrates this in part (a) with a glass pane 1 with a central, mechanically stressed, strip-shaped area 47 and two adjacent, less stressed areas 48. The mechanically stressed area 47 can, in particular, be the bending or folding area of ​​a hinged SCHOTT AG 26 16.09.2025

[0123] P06232 WO

[0124] These are displays. To ensure that no platinum particles, however small, are present, this area 47 is inspected with a higher magnification V. Sub-image (b) shows the distance d, which is set according to the spatial coordinate, corresponding to the distance 18 from source spot 7 to the glass plate 1. Sub-image (c) shows a diagram of the position-dependent progression of the magnification V. The distance d is therefore reduced in area 47, so that the magnification increases. The relative movement between glass plate 1 and source spot 7 and the number of measurements can also be adjusted to the correspondingly reduced size of the section 13. If necessary, an inspection of the less contaminated areas 48 could be omitted entirely. Regardless of whether these areas 48 are inspected or not, the examination time can be significantly reduced if only area 47 is examined at high resolution.Examples of raw glass formats for display glass for foldable displays currently include the following formats (i) - (iii):.

[0125] Format (i): 570 x 370 mm, Format (ii): 650 x 550 mm, Format (iii): 750 x 650 mm.

[0126] The display glass cut from these raw glass formats can, for example, have the following formats (iv) - (vi):

[0127] Format (iv): 88 x 73 mm Format (v): 150 x 80 mm Format (vi): 153 x 73 mm

[0128] From one of the above-mentioned raw glass formats (i) - (iii) approximately 10 to 50 display glass pieces can be cut.

[0129] The mechanically stressed, strip-shaped area 47, in which the display glass cut from these raw glass sheets is bent to fold the display together, then has a size of 100 to 300 cm² for the three raw glass formats (i) - (iii) used in display manufacturing. 2 , corresponding to approximately

[0130] 4 to 6% of the total surface area of ​​the raw glass.

[0131] The investigation duration can be reduced in proportion to the area shares during a local inspection of area 47. SCHOTT AG 27 16.09.2025

[0132] P06232 WO

[0133] The lower limit of detectability of platinum particles in thin glass is limited only by the size of the source spot 7 and the magnification achieved by the selected distances 18, 19. Platinum particles with a diameter of at least 0.5 pm, or even from a size of 0.2 pm, should be detectable, as demonstrated by the above considerations regarding contrast in the X-ray image. Since platinum particles can have very different shapes, and there can be very large differences between the longest dimension and the perpendicular directions, as is the case, for example, with so-called platinum needles, the size of a platinum particle is understood to be its smallest diameter, or, in the case of elongated particles, its smallest lateral dimension.This results in a glass sheet 1 that can be produced by a method, a device 2 or a thin-glass manufacturing plant 16 according to this disclosure, which has a thickness of preferably at most 10 mm, in particular a thickness of at most 400 pm, more preferably at least 10 pm, such as preferably a thickness in the range of 10 pm to 300 pm, wherein the glass sheet 1 has a density of less than 5 g / cm. 3 , preferably less than 3 g / cm² 3 and an area of ​​at least 50 cm 2 has, wherein the glass pane 1 has at least in a strip-shaped area 47 with an area of ​​at least 2 cm 2and preferably the entire glass plate 1 is free of platinum particles larger than 0.5 pm, preferably larger than 0.2 pm. The low density facilitates the detection of even small platinum particles due to the large difference in X-ray absorption and the resulting correspondingly higher contrast. The strip-shaped region 47 is preferably located, as in the examples above, between adjacent regions 48, or extends at a distance from two opposite edges of the glass plate 1.

[0134] In a preferred embodiment, the glass pane 1 comprises the following components in wt%: SCHOTT AG 28 16.09.2025

[0135] P06232 WO

[0136] Fig. 10 schematically shows a traced image 10 of the transmitted X-ray signal, recorded with a detector screen 9. The image 10 was taken from a glass plate 1 with a thickness of 32 pm. The image resolution is approximately 1 pm per pixel at a distance of approximately 40 cm between the glass plate 1 and the detector screen. The image was acquired with an exposure time of 200 ps, ​​an acceleration voltage of 40 kV, and a current of 40 pA. In image 10, a platinum particle 3 is shown as the intensity minimum. Around the particle is a bright area 4, indicating an increased radiation intensity. This can be attributed to a lower glass density in the immediate vicinity of the particle, a lensing effect due to surface glass warping caused by the particle, or diffraction effects, such as at the immediate interface between the particle 3 and the glass volume, or to deflecting scattering effects.The presence of such a bright halo or area 4 further simplifies particle detection. In some cases, such an effect may even enable the detection of particles 3 whose diameter or lateral dimension is smaller than the diameter of the source spot 7. Optical microscopy revealed a particle 3 diameter of 6.4 micrometers. It should be noted that, due to the shallow depth of field in optical microscopy, such a particle 3 is very difficult to locate. In contrast, the X-ray method according to this disclosure has a high depth of field, so that a particle 3 is reliably detected in the image field.

[0137] As described, the method according to this disclosure is particularly suitable for the detection of platinum particles, although other heavy metals can also be detected. A high difference in density between the glass and the particle size is advantageous in this regard. The glass of the embodiment shown in Fig. 10 has a density of approximately 2.5 g / cm³. 3 , while metallic platinum has a density of approximately 21.5 g / cm³ 3 Particle 3 is therefore approximately 8.6 times denser than the glass. Other metals that can form particles during glass production also exhibit a sufficiently high density. SCHOTT AG 29 16.09.2025

[0138] P06232 WO

[0139] Density difference is observed. Such metals include, in particular, zirconium with a density of 6.5 g / cm³. 3 , tin with a density of 7.3 g / cm³ 3 , Molybdenum with a density of 10.3 g / cm³ 3 and rhodium with a density of 12.4 g / cm³ 3Zircon, being the lightest of these metals, is still 2.6 times denser than the glass. Therefore, without limiting itself to specific examples, a further development of the method provides for the identification of particles whose density is at least 2.5 times higher than the density of the glass in glass pane 1.

[0140] SCHOTT AG 30 16.09.2025

[0141] P06232 WO

[0142] List of reference symbols SCOTDAY 31 16.09.2025

[0143] P06232 WO

Claims

SCHOTT AG 32 16.09.2025 P06232 WO Patent claims 1. Method for inspecting glass panes (1), in which a glass pane (1) is provided and examined for the presence of particles (3) embedded in the glass with a diameter of less than 50 pm, preferably less than 10 pm, wherein - the glass pane (1) is illuminated with an X-ray source (5) which has a source spot (7) with a diameter of at most 10 pm, and - the X-ray radiation transmitted through the glass pane (1) is captured on a detector screen (9) and an image (11) of the intensity of the X-ray radiation transmitted through the glass pane (1) is generated from the X-ray intensity signals of the detector screen (9), wherein - the glass pane (1) and the source spot (7) are moved relative to each other, so that the measurement covers an area of ​​the glass pane (1) which is larger overall than a section (13) captured on the detector screen (9), and wherein - a particle embedded in the glass of the glass pane (1) with a higher density than the density of the glass is detected as an intensity fluctuation in the image (11).

2. Method according to the preceding claim, wherein the distance (18) of the source spot (7) of the X-ray source (5) to the glass plate (1) is less than the distance (19) of the glass plate (1) to the detector screen (9), so that the image (11) on the detector screen (9) is magnified compared to the section of the glass plate (1) detected by the detector screen (9).

3. Method according to one of the preceding claims, characterized in that a glass pane (1) with a glass thickness of at most 10 mm, preferably at most 400 pm, in particular at most 100 pm, is examined. SCHOTT AG 33 16.09.2025 P06232 WO 4. Method according to one of the preceding claims, characterized by at least one of the following features: - Platinum-containing particles (3) embedded in the glass of the glass pane (1) are detected, -Particles (3) are identified whose density is at least 2.5 times higher than the density of the glass of the glass pane (1).

5. Method according to one of the preceding claims, characterized in that the glass plate (1) and the source spot (7) are moved relative to each other such that movement time intervals (23), in which the glass plate (1) and the X-ray source (5) move relative to each other, and measurement time intervals (24), in which the glass plate (1) and the X-ray source (5) are at rest relative to each other, alternate.

6. Method according to one of the preceding claims, in which stepwise sections (13) of the glass plate (1) are imaged on the detector screen (9), wherein the sections (13) on the glass plate (1) overlap.

7. Method according to one of the preceding claims, characterized in that the X-ray source (5) is operated continuously or in pulsed mode.

8. Method according to any one of the preceding claims 1 to 4, wherein the movement of the glass disk (1) relative to the X-ray source (5) is continuous, wherein images are taken with the detector screen (9) at regular time intervals, wherein several images are added together with an offset according to the direction of movement and the distance traveled according to the time intervals, and wherein the X-ray source (5) is operated continuously or pulsed.

9. Method according to one of the preceding claims, characterized in that during the fluoroscopy of the glass pane (1) it is continuously moved relative to the X-ray source (5), continuously producing strip-shaped images SCHOTT AG 34 16.09.2025 P06232 WO Sections (13) of the glass pane (1) are detected by the detector screen (9), which together form a two-dimensional image of an area which, in the direction of movement (35) of the glass pane (1), has a greater extent than the width of a strip-shaped section (13).

10. Method according to one of the preceding claims, characterized by at least one of the following features: - the glass pane (1) is repeatedly X-rayed at different angles to its side surfaces (10, 12), - a stack (38) with at least two stacked glass discs (1) is provided and X-rayed with an X-ray source (5).

11. Method according to one of the preceding claims, in which, during the inspection of the glass pane (1), at least one of the distances (18, 19) of the glass pane (1) to the source spot (7) and to the detector screen (9) is changed, and thus the size of the section (13) of the glass pane (1) detected by the detector screen (9) is changed, so that different areas of the glass pane (1) are detected with different spatial resolution.

12. Method according to one of the preceding claims, characterized by at least one of the following features: - the image data are examined for local contrast changes using a computing device (91), wherein the computing device (91) detects the presence of a particle (3) when such a local contrast change is present, and wherein the computing device (91) outputs a message or signal indicating that a particle (3) has been found, - the glass pane (1) is cut so that at least a part of predetermined size is obtained, and the cutting lines are placed so that a detected particle (3) is not contained in the part of predetermined size or is not located in a defined zone of the part. SCHOTT AG 35 16.09.2025 P06232 WO 13. Device for X-ray inspection of glass panes (1), in particular for carrying out a method according to one of the preceding claims, comprising - an X-ray source (5) which has a source spot (7) with a diameter of at most 10 pm, and - a detector screen (9) spaced apart from the X-ray source (5), as well as - a device (20) for storing or guiding a glass pane such that the glass pane (1) can be arranged between the source spot (7) of the X-ray source (5) and the detector screen (9), so that - the X-ray radiation transmitted through the glass pane (1) can be captured on the detector screen (9) in order to generate an image of the intensity of the X-ray radiation transmitted through the glass pane (1) from the X-ray intensity signals of the detector screen (9), and - a particle (3) embedded in the glass of the glass pane (1) with a higher density than that of the glass can be detected as an intensity fluctuation in the image, and wherein the device (2) further - a device (21) for moving the glass disk (1) relative to the X-ray source (5) comprises such that the measurement covers an area of ​​the glass disk (1) which is larger overall than a section covered on the detector screen (9).

14. Device (2) according to the preceding claim, characterized in that the glass pane (1) can be arranged between the source spot (7) of the X-ray source (5) and the detector screen (9) using the device (20) for storing or guiding a glass pane such that the distance (18) of the source spot (7) of the X-ray source (5) to the glass pane (1) is less than the distance (19) of the glass pane (1) to the detector screen, so that the image (11) of the X-ray absorption on the detector screen (9) is magnified compared to the section (13) of the glass pane (1) detected by the detector screen (9).

15. Device (2) according to one of the two preceding claims, characterized by at least one of the following features: SCHOTT AG 36 16.09.2025 P06232 WO - the distance (19) between glass plate (1) and detector screen (9) is at least a factor of 10 greater than the distance (18) between source spot (7) and glass plate (1), - the X-ray source (5) is designed such that the source spot (7) has an extent of less than 1 pm, - By means of the device (20) for storing or guiding the glass pane (1), the glass pane (1) can be arranged between the X-ray source (5) and the detector screen (9) such that the distance of the glass pane (1) to the source spot (7) of the X-ray source (5) is in a range of 1 to 10 millimeters and the distance of the glass pane (1) to the detector screen (9) is in a range of 10 centimeters to 100 centimeters - the distances (18, 19) between the glass pane (1) to the source spot (7) and to the detector screen (9), as well as the size of the detector screen (9), are selected such that a section (13) detected by the detector screen (9) on a glass pane (1) has a size of up to 150 mm in at least one direction, preferably up to 150 x 150 mm, preferably smaller than 10 x 10 mm, or an area in the range of 1 mm 2 up to 100 mm 2 has.

16. Device (2) according to one of the preceding claims, characterized by at least one of the following features: - the device (2) has at least two detector screens (9, 93) which are positioned at different angles to the side surfaces (10, 12) of a glass pane (1) which can be arranged in the device (2), - the detector screen (93) is arranged at an angle to the side surfaces (10, 12) of the glass pane (1), wherein the source spot (70) of an X-ray source (50) is arranged opposite the detector screen (93) such that an X-ray beam (15) emanating from the source spot (70) and striking the detector screen (93) perpendicularly passes obliquely through the glass pane (1).

17. Device (2) according to one of the preceding claims, characterized by several X-ray sources (5) and detector screens (9) arranged such that the detector screens (9) are moved along the glass plate (1) SCHOTT AG 37 16.09.2025 P06232 WO detect different inspection areas (38) in a direction of movement (35) relative to the X-ray sources (5).

18. Device (2) according to one of the preceding claims, characterized by a device (45) for changing the position of at least one of the distances (18, 19) of the glass plate (1) to the source spot (7) of the X-ray source (5) and the detector screen (9), wherein the device (45) for changing the position is configured to change at least one of the distances (18, 19) during the inspection of the glass plate (1) in order to inspect different areas of the glass plate (1) with different resolution.

19. Glass sheet manufacturing plant (16) with a hot forming device (17) for drawing a glass sheet (1) in the form of a continuous glass ribbon (100), and a device (2) according to one of the preceding claims for X-ray inspection of the glass ribbon (100).

20. Use of a glass sheet (1) producible by a method, apparatus (2) or glass ribbon manufacturing plant (16) as the display glass of a foldable display.

21. Glass sheet (1), producible by a method, a device (2) or a thin-glass manufacturing plant (16) according to any one of the preceding claims, having a thickness of 10 pm to 300 pm, wherein the glass sheet (1) has a density of less than 5 g / cm³ 3 , preferably less than 3 g / cm² 3 and an area of ​​at least 50 cm 2 has, wherein the glass pane (1) has at least in a strip-shaped area (47) with an area of ​​at least 2 cm 2 and preferably the entire glass pane (1) is free of platinum particles with a size greater than 0.5 pm, preferably greater than 0.2 pm.

22. Glass pane (1) according to the preceding claim, comprising the following components in wt%: SCOTDAY 38 16.09.2025 P06232 WO

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