DE10234002A1 - Product made from glass or transparent glassy material used in the production of glass containers comprises a surface having a local deformation for a lens - Google Patents

Abstract

Product made from glass or transparent glassy material comprises a surface (100) having a local deformation (102) for a lens. An Independent claim is also included for a process for inspecting a property of a substance in a product made from glass or other transparent glassy material comprising illuminating the product with diffuse light and inspecting the property of the substance with an optical inspection system.

Description

The invention relates to a product made of glass or another transparent, glass-like material and a method for inspecting a property of one in one such a product made of glass.

Various methods for marking or labeling glass are known from the prior art. For example, markings or inscriptions are applied to the glass by means of a self-adhesive, transparent film which bears an inscription. It is also known to mark or describe glass using laser beams:
From the DE 44 07 547 C2 discloses a method for producing a body made of transparent material with a marking on the inside of the body, in which there is a limited spatial area inside the body in which punctiform microcracks are formed by laser radiation. The microcracks have such a diameter that they are visible to the naked eye.

From WO 92/03297 A1 (= DE 41 266 26 C2 ) a method is known for providing a material body made of glass or plastic with a marking arranged below the surface. For this purpose, a beam of high energy density is directed onto the surface of the material body, for which the material is permeable. The beam is focused at a location that is spaced from the surface and is located within the body of material, thereby causing the marking. In this method, the material is ionized inside the glass body to be marked by the laser radiation, so that microcracks also occur.

Another corresponding procedure is known from WO 94/14567, in which an image inside the body is also generated by the formation of local microcracks.

Solid-state lasers (Nd: YAG) with a high energy density of> 10 ⁷ W / cm ² are used in the aforementioned processes known from the prior art. A disadvantage of the aforementioned methods is that only certain glasses react with such laser radiation. Another disadvantage is that the micro-crack structure deteriorates the material properties of the marked glass.

From WO 00/32349 A1 and WO 00/32531 A1 processes for marking glass are known, which also with solid-state lasers (Nd: YAG) work in which the laser parameters are selected so that no break-causing micro cracks arise. A disadvantage of this method, however, is that the generated marking with the naked eye is not recognizable. Another disadvantage is that the focus the laser beam inside the glass body has a sufficiently large glass volume or a minimum wall thickness of e.g. requires at least 1 mm to Crack growth to the surface to avoid.

In order to achieve an interaction or a marking effect despite the extensive transparency of the glass for the wavelengths of solid-state lasers, it is known to apply absorbent layers to the glass. Such a method is known for example from the EP 07 613 77 B1 is known, an Nd: YAG laser with a wavelength of 1.06 μm being used for marking the applied material layer. Furthermore, from the DE 422 428 2 A1 a corresponding method is known in which a metal-doped special glass is marked with an Nd: YAG laser.

From WO 95/05286 A1 a method for the internal marking of a glass body without changing the glass surface is known. For this purpose, a CO2 laser is used, which has an energy density of at least 6 kW / cm ² in focus in order to introduce local stresses below the surface to a depth of approx. 50 μm. A disadvantage of this method is that the markings are not visible to the naked eye.

From the DE 312 1138 C2 a method for decorating glass products is also known, in which a laser beam of such maximum energy is used that glass mass evaporates from the surface layer or causes a change in the optical permeability of the glass.

From the DE 314 5278 C2 Another method for removing material from the glass surface by means of a laser beam is known, in which the laser beam is divided into a plurality of individual beams by a partially absorbing matrix.

Furthermore, from the DE 413 2817 A1 a method is known in which the glass is selectively melted on the surface to be treated by a laser beam. A disadvantage of the material-removing processes mentioned is that suction devices are required in order to remove evaporated glass material. In addition, the material properties are adversely affected.

A particular disadvantage with the method mentioned is the necessary heat treatment of the glass in front while or after laser processing to relax the glass as the Laser processing at temperatures below the transformation temperature takes place.

From the DE 199 26878 A1 a method for engraving glass containers by means of laser beams is known which uses a lacquer which consists of a combination of a glazable base with a pigment which has the property of reacting under the action with the laser beam and changing the color of the combination used ,

Furthermore, WO 99/00215 A1 discloses a method which is based on a combination of the known Surface marking processes and Inner marking of glass based.

From WO 96/10777 A1 is a Process for marking the glass surface using UV laser radiation known, where only a microstructuring, without tools is not recognizable, can be achieved.

From the JP 09 278494 A a method for marking a glass substrate is known. A YLF laser with a wavelength of approx. 262nm is used for marking.

From the JP 10 101379 A Another method for marking glass is known. In this method, pulsating laser beams with a wavelength of 2,300 nm are used, with each point on the glass to be marked being exposed to a laser beam between three and one hundred times.

From the DE 34 25 263 A1 A method for writing information into the volume of transparent materials by means of a laser beam is known, in which the information can be written into different material depths by choosing the focusing of the laser beam.

From the DE 196 46 331 a direct-writing laser method for producing raised structures (reliefs) is known. For local plastic deformation, energy is introduced into the substrate for local, thermally induced expansion by means of a focused laser beam

From the DE 196 46 332 a laser-based method for the production of characters in the interior of a workpiece is known. Here changes are made within a workpiece at a comparatively large depth without damaging the surface.

From the DE 198 23 257 A1 a method for the defined permanent change in the extinction spectrum of metal particle-containing dielectrics by intensive laser pulses is known. The change is caused by the irradiation of intensive laser light into an extinction band caused by excitation of surface plasmons in the metal particles.

Labeled glass jars for example for filling of liquids, such as medication. The drug is typically used in the glass jar Subjected to quality inspection, by optically inspecting a property of the drug. For this purpose, optical inspection systems are known per se from the prior art known, for example, for automatically determining the number of suspended particles per unit volume in the liquid or other properties are suitable. A disadvantage of known glass vessels here that the optical inspection of the property by a on the glass jar Mark falsified becomes possible or not possible at all is.

The invention is therefore the object basically an improved product made of glass or another transparent, to create glassy material. Furthermore, the invention is the Task based on an improved procedure for inspecting a Property of a substance contained in the glass product, to accomplish.

The basis of the invention Tasks are solved with the features of the independent claims. preferred embodiments of the invention are in the dependent claims specified.

According to the invention, a is marked Product made of glass or another transparent, glass-like Material caused by one or more local deformations of the surface of the Product. Due to the local deformation or the local deformations a lens effect is realized in each case.

According to a preferred embodiment of the Invention local deformation has a substantially circular boundary on the surface.

According to a further preferred embodiment In the invention, a local deformation has a substantially oval shape Limitation on the surface.

According to a further preferred embodiment The invention provides information about the focal length of the lens effect the local deformation. A single can be used for coding Focal length of a single local deformation can be used or also different focal lengths of the same local deformation or the focal lengths of various local deformations. You can also the distances of the individual deformations used to encode information become.

According to a further preferred embodiment The invention is a local deformation to implement a spherical or cylindrical lens effect. The diameter or the extent perpendicular to the cylinder axis is maximum 0.5 mm, preferably less than 0.3 mm. The change in the surface profile of the glass perpendicular to the surface is preferably less than 0.1 mm, preferably less than 0.05 mm.

According to a further preferred embodiment According to the invention, the local deformation or deformations are generated the surface during the Production process of the product from glass, for example in a Tube drawing plant. This eliminates the need for separate processing steps after manufacturing the glass for application of markings.

A local deformation of the surface generated so that initially a marking position along a drawing process in a pipe drawing system on the surface selected is, the marking position a glass temperature above the Has transformation temperature of the glass. Then the glass with a laser pulse to apply the local deformation to the surface of the glass.

This enables a clearly visible, but micro-crack-free marking on the glass already during the manufacture of the pipe at high temperatures. The possible Integration of the marking in the production process allows the high temperatures for the application that are present anyway of the method according to the invention to use without these temperatures beyond the transformation temperature of the Glasses are generated in subsequent processing steps would.

A particular advantage of the invention lies in the fact that they are in the continuous production process inserts, without delaying it or otherwise adversely affect.

Another advantage is that the invention is the manufacture of low tension markings on the surface allowed without the creation of micro cracks, so the material properties of the manufactured glass is not adversely affected by the marking become. In a preferred embodiment, the laser beam regulated so that it only reaches its peak power for a short time. The peak power is dependent on the physical Parameters of the glass - for example its coefficient of thermal expansion and thermal conductivity - chosen to the voltage input minimize in the glass.

This purely thermal interaction is sufficient to apply visible markings on the glass surface, since the glass to be marked is above the transformation temperature, and the glass is therefore easier to deform. Correspondingly, too only a relatively low laser power required to attach the markings.

In a preferred embodiment, a pulsed quasi-continuous CO ₂ laser beam is used. By means of different pulse-pause ratios of the CO ₂ laser beam, any desired permanent markings of different patterns - for example dots, lines, or lines - can be generated on the glass surface running past the laser. These patterns are created by the local deformation of the glass surface.

The regulation can advantageously for the Generation of the laser beam can be coupled with measuring devices. This allows the glass to be made according to the errors made with the measuring devices quality assurance be recognized to mark. Provides such a measuring device, for example a glass defect, e.g. B. bubbles or knots firmly, the measuring device can be a corresponding Output signal to the control electronics of the laser. thereupon will on the surface of the material area concerned, a mark is made that later in the further production process either to identify a still necessary after-treatment or to sort out the corresponding Product can serve.

The pulse times and / or the peak powers of the Laser beam can also chosen that way that the markings are not visible to the naked eye, but only under the microscope or using a polarimeter or a wavefront sensor can be detected. The markings can also be machine-readable, for example similar to that Form of a so-called bar code.

With the method according to the invention For example, indelible markings on the Combat glass piracy. Brands, company logos can also be used or other product equipment through the inventive method unverfälschbar on the glass surface apply without affecting the material properties of the glass would adversely affect and with full integration of the application of the marking in the Produkffertigung.

Because the process is contactless works, the corresponding device from the other production process be encapsulated. This has the further advantage of low maintenance and the simple, mobile design of the marking unit.

According to a further preferred embodiment According to the invention, information encoded in the product is read through an optical system, which measures the distances between the individual deformations on the surface and or measures the focal lengths of the local deformations. By decoding this receives measured values then the payload.

Another particular advantage of the Invention is that for marking no application of foreign material is required. The local deformations can also be so create that there are no microcracks in the glass and neither Reduction in strength or the introduction of mechanical stresses he follows. This will also produce chips or chips prevented by the growth of micro cracks.

The marking is therefore preferably carried out without changing the glass structure or the chemical properties of the glass. Depending on the intensity of the marking, it is either visually visible or only in optical inspection systems. Furthermore, the marking can also be removed non-destructively if necessary, for example in a forming process or by fire polishing. A method suitable for removing such a marking is, for example, from DE 41 32 817 known. Here, a part of the surface is subjected to the energy of at least one laser or the like. Energy source for the partial melting of the glass on the surface, successively and selectively.

For example, the markings according to the invention are applied in a pipe drawing process. The manufactured in the tube drawing process Pipes are then processed into glass containers. The markings are read first and then completely or partially removed again during the manufacture of the glass containers.

It is also particularly advantageous the use of a product according to the invention in a method of inspecting a property of one in the product substance, such as a liquid. For this, a Diffuse lighting selected the lens effect of the deformations reduced. With such lighting is done the inspection of the substance in the product with a optical inspection system to check a property of the substance. At this Property can be, for example, the number of suspended particles per unit volume in a liquid or act like that.

Due to the lens effect of the local Deformation becomes the marking of the product depending on the chosen lighting either made particularly visible, especially in the case of parallel incidents Rays of light, or suppressed, if, for example, diffuse light is chosen.

Hereinafter, preferred embodiments the invention with reference to the drawings. Show it:

1 1 shows a schematic representation of a local deformation on the surface of a glass product,

2 a recording of a local deformation generated by the method according to the invention for applying a marking on the surface of the glass,

3 a schematic representation of the shape of the laser pulse to generate a local deformation on the glass surface,

4 1 shows a schematic representation of various local deformations on the glass surface for coding information,

5 1 shows a basic representation of the pulse-pause ratio of the quasi-continuous laser beam, which is used in a pipe drawing system for applying local deformations,

6 a pipe drawing system for applying local deformations to the glass surface,

7 2 shows a flowchart of an embodiment of a method according to the invention for inspecting a property,

8th a mark with circular local deformations, and

9 a single circular deformation.

The 1 shows the surface 100 of a glass product. On the surface 100 there is a local deformation 102 that on the surface 100 an oval border 104 Has.

The oval boundary 104 has the two geometric axes 106 and 108 , The extension 110 the local deformation 102 along the geometric axis 108 is preferably at most 0.5 mm, in particular less than 0.3 mm.

The 1 also shows a sectional view of the surface 100 along the geometric axis 108 , The sectional view shows that the local deformation 102 a lens shape 112 with a certain focal length along the axis 108 having.

Furthermore, the 1 a section along the geometric axis 106 , In this cutting direction there is local deformation 102 a lens shape 114 with a larger focal length.

Preferably the maximum depth 116 the local deformation 102 less than 0.1 mm, preferably less than 0.05 mm. The length of the local deformation 102 along the geometric axis 106 can be chosen arbitrarily.

Due to the lens effect of the local deformation 102 The marking created in this way becomes more or less visible depending on the selected lighting. If the incident light has essentially a parallel beam path, the lens effect becomes the most obvious. However, if diffuse light is used, the lens effect is more or less completely suppressed.

It is also possible to change the focal lengths of the lens shapes 112 and 114 to measure with an optical system. Information is preferably coded by the choice of the focal lengths, which can be obtained again by decoding the measured focal lengths.

The local deformation is preferred 102 to the surface 100 applied by bringing the glass to a temperature above its transformation temperature and then a pulsed laser beam on the surface 100 is judged. By the impact of the laser pulse on the surface 100 results in local deformation 102 ,

This is preferably done in a tube drawing system, the length of the expansion of the local deformation due to the relative speed of the glass strand in the tube drawing system to the laser 102 along the geometric axis 106 is determined when the movement in the tube drawing system is essentially in the direction of the geometric axis 106 given preferred direction. This will be explained in more detail below.

The 2 shows a single marker of the type of local deformation 102 the 1 in an enlarged view. This marking was created on the glass surface by means of a laser pulse.

First, the glass to be marked is brought to a temperature that is above the transformation temperature of the glass. Depending on the type of glass, a temperature of approx. 500 - 600 C ° is required. When the marking process is integrated into the glass production, the corresponding laser marking device is placed at a point on the passing glass strand at which the required marking temperature is greater than the transformation temperature of the glass is present.

Up is the temperature of the glass surface to be marked limited in that with the available standing laser power no longer interacts with the glass in this way there is a marking that is still visible.

The interaction of the incident Laser pulse with the glass surface is purely thermal, without it being a physical or chemical change of the glass material comes. In particular, the ionization of the Glass material and the formation of microcracks or the like essentially prevented.

The in the 2 shown marking has a length of 1.3 mm. The oval shape of the marking is achieved in that the glass to be marked executes a movement relative to the laser source, so that the length of the oval is given by the speed of movement and the length of the laser pulse.

The shows the time course of the corresponding laser pulse 3 , The laser pulse has a rise time of t _on . After the rise time, the laser power reaches its maximum that in the 2 is marked as P _peak . Immediately after reaching the maximum laser power, this falls into the fall time t _from to 0 from.

The maximum power P _peak is preferably selected such that there is no further influence on the surface to be processed and the product apart from a thermal effect. The maximum power P _peak is therefore selected as a function of the physical parameters of the glass to be marked, that is to say as a function of its coefficient of thermal expansion and its thermal conductivity. The chemical characteristics of the glass can also be taken into account.

The rise time t _an is advantageously chosen as the minimum time required to reach the maximum power P _peak . This minimum time is given by the laser used, depending on the device. The choice of laser parameters (pulse width, pulse pause) depends on the type of marking required, for example the line length.

Immediately after the maximum power P _{peak has been reached} , the supply of energy to the laser is interrupted again, so that the output power of the laser pulse falls back to 0 in the then also device-dependent fall time t _ab . When using a CO ₂ laser system, the rise and fall times can each be 50 to 60 μs, which results in a pulse width t _pulse of approx. 100 to 120 μs. However, longer pulse times of e.g. B. t _pulse = 300 μs or longer can be selected.

Through several successive and overlapping Laser pulses can also create a continuous tracer on the surface become. This characteristic strip can be essentially constant Have depth. Alternatively, the depth can be determined by the time sequence the laser pulses are modulated to provide information in the label save. By measuring the depth along the characteristic strip and demodulation the information can then be recovered.

The 4 schematically shows a further embodiment of a glass product according to the invention. This has a surface 400 with local deformations 402 . 404 . 406 and 408 ,

The local deformation 402 has a circular boundary 410 on the surface 400 , The circular boundary 410 has a diameter 412 , The local deformation 404 also has a circular boundary 414 with a diameter 416 , The local deformation 406 has a circular boundary 418 with a diameter 420 , In the embodiment shown, the diameter is 420 essentially identical to the diameter 412 ,

The local deformation 408 corresponds to the local deformation 102 of the embodiment of the 1 , The local deformation 408 has an oval border 424 , according to the oval limit 104 the 1 ,

The local deformations 402 to 408 on the surface 400 are along a preferred direction 426 arranged. This preferred direction 426 is due to the relative movement of the surface 400 given to the laser.

The 4 also shows a section along the preferred direction 426 , As shown in the section, the local depression 402 a lens shape 428 who have favourited Local Deepening 404 a lens shape 430 who have favourited Local Deepening 406 a lens shape 432 and the local deepening 408 a lens shape 434 ,

Through the lens shape 428 becomes a certain focal length of the local depression 402 Are defined. The lens shape 432 is essentially identical to the lens shape 428 so that essentially the same focal length results.

The lens shape 430 on the other hand has a significantly lower curvature and thus a larger focal length. The local deformation 408 has two different focal lengths, namely the lens shape 434 certain focal length and another by the contour of the local deformation 408 lens shape given perpendicular to it (see lens shape 112 the 1 ).

The local deformation 402 is from local deformation 404 by a distance 436 spaced; between the local deformations 404 and 406 there is the distance 438 and between the local deformations 406 and 408 the distance 440 ,

By choosing the appropriate distances 436 . 438 and 440 and the focal lengths of the local deformations 402 to 408 information can be found in the surface 400 in coded or uncoded form deposit.

For the coded storage of the information, this is assigned a certain focal length / distance or focal length combination or only a certain focal length in a suitable coding method. Then the surface is applied 400 with an appropriately controlled, pulsed laser to generate the corresponding local deformations on the surface 400 ,

The 5 shows schematically a representation of the time course of the emitted laser pulses when the surface 400 moving past a laser head at a certain pulling speed. The shape of the laser pulses corresponds in each case to the laser pulse 3 , By varying the pulse widths t _pulse , the different local deformations on the surface can be generated with different boundary contours. In contrast, the duration of the pulse pauses t _{pause determines} the distance between the local deformations generated on the surface. Furthermore, the marking on the surface is determined by the setting of the laser optics.

The 6 shows a system for the continuous production of glass, for example glass tube, in a tube drawing system. Here, for example, the Danner method can be used, which in itself is derived from the US 1,218,598 is known. Furthermore, the VeIlo method and the A-Zug method ( DE-AS 1025 581 ) or another glass-drawing process are used.

The glass material is in the tube drawing machine 1 at a certain speed essentially translationally in the direction of the arrow 2 emotional. The pulling speed is below 6 m / s, preferably about 4 m / s.

The one from the glass material 1 Existing glass tube train passes in the tube drawing system 3 first the measuring devices 3 , The measuring devices 3 are used to examine one or more material properties of the glass material 1 , for example checking for bubbles, knots or other material irregularities, defects or other properties. The measuring devices can advantageously also be arranged approximately at the level of the point labeled 400 ° C. along the glass strand. If the laser marking is to be used for fault marking, then the laser location in the direction of drawing must be selected according to the measuring devices.

If a certain test condition is not met, the measuring devices give 3 a corresponding signal from a line 4 to a control 5 of a laser 6 is transmitted.

The laser 6 exists in addition to the control 5 from a CO2 laser head 7 and a corresponding cooler 8th and a high frequency power supply 9 , The laser head 7 generated with a corresponding control by the control 5 a CO2 laser pulse that has a focusing lens 10 on the glass material 1 is judged.

The focusing optics 10 points at the the glass material 1 facing side one in the 3 Optical rinsing not shown in detail 11 on. The temperature is in the area where the laser beam from the laser head 7 on the glass material 1 strikes approx. 600 ° C in the example under consideration, ie lies above the transformation temperature of the glass material 1 ,

The temperature of the glass material drops in the subsequent sections of the tube drawing system 1 continuously to 400 ° C or to 200 ° C. There is a drawing machine at the rear end of the pipe drawing system 12 that the glass material 1 set in the desired translational movement. Behind the drawing machine 12 the drawn glass material becomes tubes 13 divided, the postprocessing if necessary 14 be subjected.

The laser head 7 is controlled by the 5 of the laser 6 regulated so that the passing glass material 1 of the tube train is subjected to laser pulses which essentially only have a thermal influence on the surface of the glass material 1 perform as above with respect to the 1 and 2 explained. The exact position for making a mark is determined by the focusing optics 10 certainly.

In the considered embodiment of the 3 is the focusing optics 10 at approx. 63.5 mm working distance from the surface of the glass material 1 , Any deviations from the ideal focus due to tube tension fluctuations of, for example, + 1 mm can be neglected due to the depth of field of the radiation.

The optical rinse 11 ensures the rinsing of the focusing lens of the focusing optics 10 with a directed gas flow to protect the focusing lens from glass dust or the like, for example.

For example, the laser parameters of the control 5 are set so that the pulse width tpuls (cf. 2 ) Is 60 μs and the pulse frequency is 10 kHz. The peak power can be approx. 200 W, which corresponds to an average power of approx. 120 W. Due to the drawing speed of approx. 4 m / s, this results in marking by means of lines with a line dimension of approx. 0.25 × 0.1 mm, the lines each being approx. 0.4 mm on the surface of the glass material 1 are spaced.

The markings created in this way are without aids on the end product glass tube 13 as well as on post-processing products, e.g. B. ampoules, visible to the naked eye. No bulges on the outside of the glass surface and no negative stresses or even micro cracks are induced. This can be done, for example, by heat treating the ampoules (cooling furnace) and Verify thermal shocks in which the corresponding products have no differences compared to unmarked products.

Through appropriate training of the focusing optics 10 however, any marking pattern can be created on the glass surface. This can be, for example, decorative patterns, brands, logos, product features or other markings, for example for production monitoring. In particular, markings can also be applied to the pipes, such as calibration marks or other markings for fill levels. It is advantageous for the application of calibration lines if the pipes rotate during production.

The laser optics can also be a beam splitter have simultaneous application of two or more pulses and / or a diffractive optics for generating any pattern.

It is also possible to use the laser 6 and / or the focusing optics 10 to be arranged to be movable relative to the pipe drawing system parallel to the pipe drawing, so that the laser beam is parallel to the glass material over a certain distance 1 in the direction of the arrow 2 can run along, for example, more complex patterns on the surface of the glass material 1 applied. This enables the optics to move along with the drawing speed simultaneously with the pipe pull movement. Alternatively, a scanning device can also be used. After completing the appropriate marking, the laser 6 and / or the focusing optics 10 moved back to the starting position to prepare a new marking step.

Alternatively or additionally, the control 5 from a coding unit 16 driven. For this purpose, information to be encoded is first entered into the input unit 15 entered. At the input unit 15 it can be, for example, a personal computer. Also the coding unit 16 can be realized by the personal computer, that is, an appropriate computer program.

Through the coding unit 16 the information to be encoded is encoded at focal lengths and / or at intervals of successive local deformations. These in turn correspond to a specific sequence of pulse widths t _pulse and pulse pauses t _{pause for} producing corresponding local deformations on the glass surface.

The 7 illustrates an application of a product according to the invention. In step 700, the production of the product takes place in a method according to the invention, for example in a raw drawing system, as with reference to FIG 6 explained above. During the production process, coded information is introduced into the glass product in the form of local deformations. The information can, for example, be product information.

In the step 702 the liquid product is filled into the glass product by the user. The liquid can be a drug, for example.

To check a property of the liquid is in the step 704 diffuse light turned on to suppress the lens effect of local deformations on the surface of the glass product.

In the step 706 the properties of the liquid are checked with an optical inspection system. It is advantageous here that the mode of operation of the optical inspection system is not impaired by the local deformations on the glass surface.

On the other hand, the encoded information in the step 708 read by the user of the glass product. For this purpose, the distances and / or the focal lengths of the local deformations on the surface of the glass product are measured. These measured values are decoded in step 710 and the decoded useful information is output. An appropriately programmed personal computer can be used for decoding and outputting the information.

The 8th shows a surface 800 a glass product with local deformations 802 which are spaced 2.13 mm apart. The local deformations 802 have an essentially circular boundary and therefore each have the effect of a spherical lens.

In the exemplary embodiment considered here, the local deformations are 802 with a CO ₂ laser with an output of 30 watts, 250 K Coherent. The speed of the glass strand in the tube drawing system was 2.47 m / s. The application of the surface 800 with the laser pulses at a temperature of T = 510 ° C.

The 9 shows an enlarged view of a single local deformation 802 , The local deformation 802 has a diameter of approx. 0.4 mm.

01

glass material

02

drawing direction

03

Measuring device

04

management

05

control

06

laser

07

laser head

08

cooler

09

RF power supply

10

focusing optics

11

optics flushing

12

drawing machine

13

Tube

14

postprocessing

15

input unit

16

coding

100

surface

102

local deformation

104

oval limit

106

geometric axis

108

geometric axis

110

expansion

112

lens shape (Focal length)

114

lens shape (longer focal length)

116

depth

400

surface

402

local deformation

404

local deformation

406

local deformation

408

local deformation

410

circular boundary

412

diameter

414

Circular boundary

416

diameter

418

Circular boundary

420

diameter

424

oval limit

426

preferred direction

428

lens shape

430

lens shape

432

lens shape

434

lens shape

436

distance

438

distance

440

distance

800

surface

802

local deformation

Claims (13)

Product made of glass or a transparent, glass-like material with a surface ( 100 ; 400 ; 800 ), the surface being at least one local deformation ( 102 ; 402 . 404 . 406 . 408 ; 802 ) to realize a lens effect. The product of claim 1, wherein the deformation is a substantially circular boundary ( 410 . 414 . 418 ; 802 ) on the surface. The product of claim 1, wherein the deformation is a substantially oval boundary ( 104 ; 424 ) on the surface. The product of claim 1, wherein the deformation is a characteristic strip is formed, and preferably in the depth profile of the characteristic strip information is modulated on. Product according to one of the preceding claims 1 to 4, wherein the deformation is reversible, and preferably removable in a fire polishing step is. Product according to one of the preceding claims 1 to 5, wherein the deformation has at least a first focal length, and information about the Choice of at least the first focal length is coded. The product of claim 6, wherein the deformation is a second focal length has, and about the choice of the first and second focal lengths encodes information is. Product according to one of the preceding claims 1 to 7 with several local Deformations, where the deformations are at a distance, and over the Selection of the distance an information is coded. Product according to one of the preceding claims 1 to 8 with at least one first local deformation, which has first and second focal lengths and with a second local deformation that is a third focal length and which is spaced from the first deformation by a distance is, by choosing the first, second and third focal lengths and information is coded by the choice of the distance. Product according to one of the preceding claims 1 to 9, wherein the lens action essentially that of a spherical one or a cylindrical lens. Product according to one of the preceding claims 1 to 10, wherein an expansion ( 110 ) the deformation perpendicular to a preferred direction ( 106 ; 426 ) is at most 0.5 mm, preferably at most 0.3 mm. Product according to one of the preceding claims 1 to 11, wherein a maximum depth ( 112 ) the deformation is at most 0.1 mm, preferably at most 0.05 mm. Method for inspecting a property of a substance contained in a product made of glass or another transparent, glass-like material, the surface ( 100 ; 400 ; 800 ) the product has at least one local deformation ( 102 ; 402 . 404 . 406 . 408 ; 802 ) for the realization of a lens effect, with the following steps: - Illumination of the product with diffuse light, - Inspection of the property of the substance with an optical inspection system.