WO2011045738A1

WO2011045738A1 - Method for generating information on a surface and/or on the inside of a glass ceramic body and cook top having a glass ceramic plate

Info

Publication number: WO2011045738A1
Application number: PCT/IB2010/054606
Authority: WO
Inventors: Miguel Angel BUÑUEL MAGDALENA; Diego Dionisio Micolau; Francisco Javier Ester Sola; Jose-Ramon Garcia Jimenez; José Ignacio Peña Torre; Fernando Planas Layunta; Daniel Sola Martinez
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2009-10-15
Filing date: 2010-10-12
Publication date: 2011-04-21
Also published as: ES2363360B1; EP2488324A1; ES2363360A1

Abstract

The invention relates to a method for generating information (7 to 17) on a surface (11) of a glass ceramic body (2), said information being generated by the action of a laser beam on the surface (11) and the laser being operated in the Q-switched mode for generating the information (7 to 17). The structuring of the surface (11) by means of the laser beam for generating the information is carried out with a hatch distance of less than or equal to 0.2 mm. The invention also relates to a method for generating information on the inside of a glass body and to a cook top having a glass ceramic plate (2).

Description

Method for generating information on a surface and / or inside of a glass ceramic body, and hob with a glass ceramic plate

The invention relates to a method for generating information on a surface of a glass ceramic body and to a method for generating information in the interior of a glass ceramic body. Furthermore, the invention relates to a hob with a glass ceramic plate, which has information generated by the method. From DE 20 2006 004 064 U1 a laser-printed glass ceramic disc is known. It is possible to produce inscriptions on the surface of the glass ceramic pane and / or ornaments in the interior of the glass ceramic pane by means of laser processing. In this case, a green laser in the wave range of 532 nm can be used. Moreover, it is known from DE 103 04 382 A1 from which different materials the glass-ceramic material can be constructed, wherein these glass-ceramic materials can be photo-patterned and thereby laser beams can be used. In the procedures known from the prior art by means of the laser radiation very specific laser parameter settings are given, which lead to specific results.

Especially with the use of laser light for material processing, the desired results are essentially dependent on the laser itself and the material to be processed. The smallest changes can therefore already lead to no longer useful results. It is therefore essential to develop individual approaches for the individual situation and the desired requirements.

Precisely in the processing of glass ceramics and the application or introduction of information, therefore, very specific requirements must be placed on the quality of the result of this design. For example, in cooking hobs that may have colored glass-ceramic materials, the introduction or application of information is particularly precise and user-friendly, as well as easy to view and easy to train. Especially with different lighting conditions, therefore, this information must be easily and safely detected.

It is an object of the present invention to provide methods by which information in and on a glass ceramic body can be applied in a cost-effective and yet very precise and easy-to-see easily comprehensible under different conditions. In addition, it is an object to provide a cooktop with a glass ceramic plate, which is accordingly user-friendly and easily visible, as well as clearly identifiable information. These objects are achieved by methods having the features of claim 1 or 9. In addition, this task is solved by a hob, which has the features of claim 14.

According to a first aspect of the invention, information is generated on a surface of a glass ceramic body. Information is generated by the action of a laser beam on the surface, whereby the laser is operated to produce the information in Q-switched operation, the so-called "Q-switch operation." In addition, the structuring of the surface with the laser beam is used to form the information This mean pitch is also referred to as "hatch distance" and indicates, for example, the mean distance between two adjacent pits produced by the laser light. Especially with regard to the material specifications of a glass ceramic and the desired configuration of information on the surface of the glass ceramic allows such operation of a laser with such structuring a particularly durable application of information, which can also be displayed extremely precisely beyond. In this way, the most complex information can be generated in detail and thus in a clear and comprehensible manner for the user, even in the most varied light conditions.

For example, the Ceran Suprema or ECO + manufactured by Schott is preferably used as the glass-ceramic material. These are also dark Glass ceramic materials, so that in these the application of information on the surface is preferred.

Preferably, this structuring enables both the formation of individual, precise lines and the areal display of information.

It is preferably provided that a diode-pumped solid-state laser is used as the laser, which in particular has a very high pulse power of a few kilowatts. Preferably, a Nd: YV04 laser is used. In particular, a pulse repetition frequency in the Q-switched mode is set between 20 kHz and 40 kHz, in particular between 25 kHz and 35 kHz. This means that this repetition frequency in combination with the Q-switched very high energy pulse at short time intervals enables the desired contrasts and precise representations of information in the form of complex symbols or even letters and numbers, especially with regard to the precise surface processing of this specific glass-ceramic material allows. Especially in the presentation of information on a glass ceramic plate of a hob so a variety of complex symbols can be generated, which can be understood comprehensible and detailed to the user, and this at a certain distance from a hob in different lighting conditions and different viewing directions easy is possible.

Preferably, a laser beam having a wavelength of 532 nm is produced for the processing of the glass ceramic material, which makes possible, in particular with regard to the material design of the glass ceramic per se, a very precise and also in view of undesired destruction of the material reliable laser beam processing.

Thus, it can be provided that with a fixed specification of the power of the laser beam and a predetermined deflection of the laser beam with which it is moved over the surface, an increase in the pulse repetition frequency is possible, thereby reducing the pulse power and the pulse energy is reduced and increasing the Dot density of the information contour to be generated is generated. Preferably, it is provided that the laser with maximum output power in view of the Beam energy is operated in the generation of I nformation. It can also be provided that the laser is operated at a reduced power, for example> 80%, but <100% of the maximum output power with regard to the beam energy, so that an energy variation is possible during the generation of the given information, if necessary. so that in this context adjustments and individualities in the information generation are possible. Precisely when higher energies are required at specific points of the generated information, this energy can also be ramped up during the generation of information so that the laser beam power can then be adapted to the situation.

It is preferably provided that the laser beam is positioned to the surface in such a way that the beam focus, viewed in the direction of the beam, lies in a value range between +/- 2 mm around the level of the surface of the glass body to be processed. Thus, it can be provided that the focus of the laser beam is formed directly on the surface and thus very concentrated energy is concentrated on a very small point. Due to the variation in the direction of the beam length with regard to the focus positioning to the surface, it is possible in this respect to produce situation-specific changes, so that even very specific areas of information generation can thereby be designed individually. For the material processing of this specific glass-ceramic material, the laser beam is preferably focused in such a way that it has a minimum energy density of 10 kW / cm ² .

In particular, it is provided that the laser beam is moved when generating the information on the surface at a deflection speed between 100 mm / s and 1000 mm / s wi rd. Also, depending on the information to be generated, the deflection rate may be constant throughout the generation of the information. However, it can also be provided an individual speed change, so that here too at specific positions of the information to be generated, the most appropriate deflection speed is generated. Especially with regard to the composite objects of information, it is possible to compare the generating sections of the information in combination with the variable parameter deflection speed, energy density of the beam, focus positioning of the beam relative to the beam Surface and the pulse repetition frequency the most appropriate Processing situation to be generated. This variability during the generation of the information on the surface ensures high flexibility and thus also makes it possible to form very specific information.

Preferably, it can be provided that information areas which are practically filled to a minimum and thus do not require large-area material processing are typical for contours or simple lines. Preferably, it is provided in such information generations or sections of information that initially a maximum deflection speed of the laser beam is specified in the process, and then subsequently the maximum distance is specified with respect to the beam spacing in order to ensure a homogeneous material processing in the area can.

On the other hand, it can be provided that, in planar material processing, in which planar information is to be generated by the laser light, preferably the maximum average structure spacing is initially predetermined, whereby a good contrast is achieved and, moreover, the most homogeneous possible flat representation of the information area is made possible; without recognizing every single line drawn by the laser during material processing. Thereafter, a maximum decay can be made on the basis of the present invention. In this second case, the deflection speed is smaller than in the first case, with the structure distance being greater in the second case than in the first case.

A further aspect of the invention relates to a method for generating information in the interior of a glass ceramic body, in which the information is generated by the action of a laser beam. The laser is operated to produce the information in Q-switched operation, and the structuring of the glass body inside with the information to be generated by the laser beam is carried out with an average pitch of less than or equal to 0.2 mm. Here, too, a specific operation of a laser and, in particular, feature sizes for material processing with the laser are specified in a specific information generation inside the glass body, so that the information generated detected here very precisely and safely for an observer and understandable even in different air conditions can be. Preferably, the pulse repetition frequency in the Q-switched operation when generating information in the interior of the glass body between 50 kHz and 70 kHz, in particular set to 60 kHz. Preferably, the maximum output power of the laser both in the generation of information on the surface of the glass body and in the interior of the glass body between 7 W and 25 W. Especially in the generation of information inside the glass ceramic body, the optimal distance of the focus of the laser beam 1 to 2 mm lower than in the procedure for generating information on the surface of a glass body.

It is particularly preferred that in the generation of information inside the glass body with a Q-switched laser having a wavelength of the laser beam of 532 nm and an output power between 7 W and 25 W maximum, the deflection speed between 100 mm / s and 400th mm / s, in particular between 200 mm / s and 400 mm / s. This is preferably provided for transparent and transparent glass-ceramic materials as well as for dark and essentially for the human eye non-transparent glass-ceramic materials.

In particular, it is provided that the average structure spacing is between 0.1 mm and 0.2 mm.

Furthermore, the invention relates to a hob with a glass ceramic plate which has information on the surface, which are produced by a method according to the invention or an advantageous embodiment thereof according to the first aspect and / or which has information inside, by a method according to the invention or a advantageous embodiment according to the second aspect, are generated.

Embodiments of the present invention will be explained in more detail with reference to a schematic figure. The single FIGURE shows a hob 1, which has a glass ceramic plate 2. On the glass ceramic plate 2 preparation container, such as pots, pans or the like can be placed. The glass ceramic plate 2 has cooking zones 3, 4, 5 and 6. Under the glass ceramic plate 2 3 to 6 radiators are mounted under the identified cooking zones, which can be heated by the cooking zones 3 to 6. The cooking zones 3 to 6 are made for a user by displaying the contours 7, 8, 9 and 10. These contours 7 to 10 thus represent the boundary of the cooking zones 3 to 6. It can be provided that these contours 7 to 10 are produced by means of laser processing of the glass-ceramic material as information. In particular, it is provided that a diode-pumped solid-state laser is used, which operates in Q-switched operation and has a maximum output power between 7 W and 25 W. To generate the contours 7 to 10, which are generated on the surface 1 1 of the glass ceramic plate 2, parameter settings are given, which are a pulse repetition frequency in Q-switched operation between 25 kHz and 35 kHz, in particular 30 kHz. The laser beam is generated with a wavelength of 532 nm, wherein the laser beam is positioned to the surface 1 1, that the beam focus in the direction of the beam and in the embodiment shown directly on the surface 1 1. It may also be provided in other generations of information on the surface 1 1 of the glass-ceramic material, that this beam focus in the direction of the beam viewed in a range of values between +/- 2 mmum the level of the surface 1 1 considered. As a result, structuring specifics can be achieved which improve the viewing and precise representation of the information on the surface 11. In particular, it is provided that the contours 7 to 10 are moreover produced in such a way that the structuring of the surface 11 takes place with the laser beam with an average structure spacing of less than or equal to 0.2 mm.

The laser beam is also focused so that it has an energy density of at least 10 kW / cm ² , wherein the deflection speed is between 200 mm / s and 400 mm / s.

In particular, it is provided that the laser beam is generated in the generation of information on the surface 1 1 and thus the contours 7 to 10 with maximum output power and thus 100%. Depending on which information is generated on the surface 11, different parameter settings of the laser can be made. Thus, in this regard, a high-precision information on the surface that can be reliably and easily recognized in the most diverse lighting conditions can be present even if the pulse repetition frequency at 20 kHz at a maximum output power of the laser beam of 100%, a pitch of 0.06 mm and a deflection speed of 350 mm / s, in which connection a time of about 4.87 seconds is required to produce one square centimeter of machined material. Correspondingly, with the pulse repetition frequency of 40 kHz and an average structure distance of 0.2 mm and a deflection speed of 150 mm / s, a corresponding surface treatment is possible within 6.83 seconds. In a further embodiment, at 100% output power, a pulse repetition frequency of 20 kHz and an average structure spacing of 0.08 mm at the deflection speed of 250 mm / s, a corresponding material surface can be treated or engraved and this can be done in 5.12 seconds. Within a period of 5.67 seconds, this surface processing for information generation on the surface 11 takes place, at 100% output power, the deflection speed at 300 mm / s, the pulse repetition frequency at 20 kHz, and the mean pitch at 0, 06 mm lies.

Furthermore, it can be provided that on the surface 11 further information in the form of the symbols 12, 13, 14 and 15 are generated. These are also generated by a corresponding laser material processing and can be, for example, symbols that represent operating elements or functionalities of the hob 1. In this regard, operation icons may be displayed. In addition, a control panel 16 can be marked accordingly in its contour 17, whereby a corresponding surface treatment with laser radiation is also formed here.

In addition, in addition to or instead of the cooking field 1 in the interior of the glass ceramic plate 2 information 18 and 19, which are also only exemplified as a box. Again, letters and / or numbers and / or symbols may be generated. Preferably, here is also a Q-switched diode-pumped solid-state laser with a maximum output power between 7 W. and 25 W is used for generating information 18 and 19, whereby here too the wavelength of the laser beam is 532 nm. In particular, however, here is the pulse repetition frequency at 60 kHz, the deflection speed between 200 mm / s and 400 mm / s and the average structure spacing is between 0.2 mm and 0.2 mm.

In particular, the glass-ceramic material is Ceran Suprema from Schott. Accordingly, it is also possible to use ECO + as the glass-ceramic material.

Both the number and the shape as well as the position of the information generated by said specific laser beam machining on the surface 11 and inside the glass ceramic plate 2 is merely exemplary. Essential are the specific laser parameters in connection with the processing of the glass ceramic material, so that the information generated can be detected reliably, easily, accurately and precisely as well as for the user in different viewing angles to the glass ceramic plate 2 and in different lighting conditions safely and easily and in this regard even the most complex symbolic representations can be realized. This also against the background of a very small and compact representation on or in the glass ceramic body, often with minimal space requirements for this information presentation, especially for symbols 12 to 15, 16 and 17 and 18 and 19.

LIST OF REFERENCE NUMBERS

1 hob

2 glass ceramic plate 3, 4, 5, 6 cooking zones 7, 8, 9, 10 contours

1 1 surface

12, 13, 14, 15 symbols

16 control panel

17 contour

18, 19 Information

Claims

claims

1 . Method for generating information (7 to 17) on a surface (1 1) of a glass ceramic body (2), in which the information is generated by the action of a laser beam on the surface (1 1), characterized in that the laser is used to generate the Information (7 to 17) is operated in Q-switched operation and the structuring of the surface (1 1) with the laser beam to r generating the information with a mean pitch of less than or equal to 0.2 mm.

2. The method according to claim 1, characterized in that the pulse repetition frequency of the laser pulses in Q-switched operation between 20 kHz and 40 kHz, in particular between 25 kHz and 35 kHz, is set.

3. The method according to claim 1 or 2, characterized in that the laser beam is generated with a wavelength of 532 nm.

4. The method according to any one of the preceding claims, characterized in that a diode-pumped solid-state laser is used as the laser.

5. The method according to any one of the preceding claims, characterized in that the laser beam is positioned to the surface (1 1) that the beam focus in the direction of the beam considered in a range of values between +/- 2 mm to the level of the surface (1 ) of the glass body (2) to be machined.

6. The method according to any one of the preceding claims, characterized in that the laser beam is focused so that it has an energy density of at least 10 kW / cm ² .

7. The method according to any one of the preceding claims, characterized in that the laser beam when generating the information on the surface (1 1) with a deflection speed between 100 mm / s and 1000 mm / s is moved.

8. The method according to any one of the preceding claims, characterized in that the laser beam is operated to generate the information with a power of at least 80% of the maximum power of the laser.

9. A method for generating information (18, 19) in the interior of a glass ceramic body (2), in which the information (18, 19) are generated by the action of a laser beam, characterized in that the laser for generating the information (18, 19 ) is operated in Q-switched operation and the structuring of the glass ceramic body (2) takes place in the interior with the laser beam for generating the information (18, 19) with an average pitch of less than or equal to 0.2 mm.

10. The method according to claim 9, characterized in that the pulse repetition frequency in the Q-switched operation between 50 kHz and 70 kHz, in particular 60 kHz, is set.

11. The method according to claim 9 or 10, characterized in that the laser beam in generating the information (18, 19) in the interior of the

Glass ceramic body (2) with a deflection speed between 100 mm / s and 400 mm / s, in particular between 200mm / s and 400 mm / s, is moved.

12. The method according to any one of the preceding claims, characterized in that the maximum output power of the laser is between 7 W and 25 W.

13. The method according to any one of the preceding claims, characterized in that as information letters and / or numbers and / or symbols are generated.

14. hob with a glass ceramic plate (2) which on the surface (11) information (7 to 17), which are generated by a method according to one of claims 1 to 8 and / or inside information (18, 19) which are produced by a method according to any one of claims 10 to 13.