Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/382—Contact thermal transfer or sublimation processes
  • B41M5/38207—Contact thermal transfer or sublimation processes characterised by aspects not provided for in groups B41M5/385 - B41M5/395
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
  • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
  • B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
  • B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
  • B32B17/10807—Making laminated safety glass or glazing; Apparatus therefor
  • B32B17/1099—After-treatment of the layered product, e.g. cooling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/24—Ablative recording, e.g. by burning marks; Spark recording
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/001—General methods for coating; Devices therefor
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
  • C03C23/0005—Other surface treatment of glass not in the form of fibres or filaments by irradiation
  • C03C23/0025—Other surface treatment of glass not in the form of fibres or filaments by irradiation by a laser beam
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/382—Contact thermal transfer or sublimation processes

Definitions

• the object of this invention is a method and a device for making visually observable markings onto the surface of glass or other transparent material by using a laser beam.
• transparency implies that the material does not essentially absorb light energy on the wavelength of the laser beam mentioned.
• Markings are currently made by, e.g., sand blasting, silk screen printing, transfer marking methods, or the like.
• the main problem of the methods used has been a difficulty in making individualized glass markings, e.g., serial numbers or changing bar codes in industrial production line applications.
• the advantages of laser marking can be considered reliability, stability, convertability and flexibility.
• the applicability of an Nd/Yag type laser for marking glass has generally been considered weak or nearly nonexistent because light is not absorbed by glass at this wavelength.
• the Nd/Yag type laser generally refers to a laser in which the laser beam is generated in an artificially grown crystal, i.e., in a laser rod.
• the wavelength of the Nd/Yag laser is 1064 nm. This wavelength causes the effect of the beam passing through the glass.
• Laser marking can be effected either by using a masking technique in which the laser beam does not move and the desired figure is cut or etched on a cover plate, i.e., a mask, or by using oscillating mirrors.
• the oscillating mirrors refer to refracting mirrors which are a part of the beam deflection unit of the marking laser and which are moved to deflect the laser beam so that it follows the shapes of the desired marking pattern.
• the mirrors are controlled by servo motors or galvanometers with the aid of a computer. By using the oscillating mirrors, fairly high speeds of movement of the beam, such as 1500 mm/s, can be achieved.
• Laser marking is a frequently used method which has not been applied in glass marking previously, but transparent objects have generally been marked by using traditional means. These methods provide a fairly low marking cycle time. However, there are many production processes which require fast and individualized markings on transparent objects for subsequent identification of the product. There are no laser marking applications for such processes. Furthermore, many marking methods require that the marking is made in a low-pressure chamber.
• a laser beam directed through a transparent object and a metal vehicle placed in the vicinity of the surface to be marked has been used, according to EP patent EP 2738, to form coatings or conductive patterns, such as strip conductors, on the surfaces of isolating bodies.
• the patent deals with a slightly different problem than the present invention as it does not endeavour to achieve a visual distinguishability of a pattern. Copper, brass, chrome, and aluminium are mentioned as vehicles. The patent also assumes that the transparent material is homogenous.
• the object of the present invention is a method and a device for making individual and visually distinguished markings on transparent mediums quickly and advantageously in industrial production line applications. Another object is that the method can be applied for marking laminated glass structures without damaging any parts of the structure.
• the method according to the invention is characterized in that the laser beam is conducted through the medium to be marked and focused on the vehicle on the opposite side, such as a colourant body, a metal sheet, or similar film so that a reaction is generated in the vehicle, comprising heating, melting and evaporation, and which causes the creation of a pattern on the surface of the vehicle, a pattern which can be distinguished very well when examined visually.
• the marking is essentially effected at normal pressure.
• the invention is also related to a device for implementing the method.
• the device according to the invention is characterized in that means are provided on the opposite side of the medium to be marked, with respect to the laser beam, for bringing the vehicle, such as a colourant body, metal sheet or corresponding film to the vicinity of the surface to be marked, the equipment focusing the laser beam against the vehicle.
• the device is further characterized in that the part of the equipment where the marking is effected is essentially at normal pressure.
• the black framing part of a windscreen serves as a vehicle and the laser beam is used to make the markings by removing the vehicle.
• An essential difference of the present invention as compared with EP 2738 is a realization according to which the amount of the vehicle does not have to be so large that it would constitute an actual coating when making visual markings. In this case the consumption of vehicle is minimum and the whole procedure can be carried out considerably faster than the coating according to EP 2738.
• the method and device according to the invention has thus been optimized in the manner described below so that the pattern created on the surface of the material to be marked can be distinguished in the best possible way when examined visually, and that the laser beam does not damage the possible intermediate layers of the structure to be marked.
• the power of the laser beam is preferably 2 and it is preferably moved at a speed of 2 mm/s.
• the power of the laser beam is preferably 50 and the speed of movement 250 mm/s.
• the figure illustrates a diagram of the method according to the invention.
• Reference number 3 is used to mark a laser head, and laser beam 2 coming from the laser head is focused on vehicle 1.
• Laser beam 2 travels through layers of glass 5 and a laminated layer 4.
• Vehicle 1 should be placed about 0.1 mm from the lower surface of the glass in order for the mixing of the vehicle and the glass to be effected in the best possible way.
• the ambient conditions are normal air, pressure, and temperature.
• the forming of plasma in the vehicle and the adhesion of the marking on the glass surface can also be improved by surrounding the operating range by a gas atmosphere instead of air, such as argon which improves the reaction.
• the power density of the laminate must be the lowest possible because otherwise the laminate bubbles and breaks the glass or at least weakens its strength.
• the power density of the laminate is influenced by the power and the optical geometry of the laser beam, i.e., the original diameter of the laser beam and the focal distance of the optics used for focusing.
• the power density is highest near the focal point of the beam which is situated on the surface of the vehicle, according to the method.
• the focal point i.e., the focus, cannot be removed away from the laminate, i.e., below the surface of the vehicle because then the power density in the vehicle, correspondingly, is too low for making the marking.
• Vehicle 1 must be a kind of mixture the factors of which influencing the markability include, e.g., the melting point, the boiling point, heat transmission, density, etc.
• suitable vehicles include, e.g., the colouring agent used for silk screen printing dyeing of windscreen surfaces, brass, stainless steel, and zinc aluminium alloys.
• the markability can be influenced in a positive way.
• a mixture with a fairly high melting point provides good stability and a mixture with a fairly low melting point provides a good difference in contrast.
• the mechanical and chemical stabilities of the marking are important regarding the applicability of the method, so that it is not possible to later alter or remove the marking intentionally or unintentionally.
• the mechanical stability is preferably tested by rubbing the marking with different mediums.
• the chemical stability is tested by exposing the marking to corrosive and solvent substances.
• Example 1 The best marking result on a glass surface is achieved by using, as the vehicle, a silk screen printing colour which is used by windscreen manufacturers for dyeing the edges of windscreens. Examples are shown in the following for applying the method in different vehicles.
• Example 1 The best marking result on a glass surface is achieved by using, as the vehicle, a silk screen printing colour which is used by windscreen manufacturers for dyeing the edges of windscreens. Examples are shown in the following for applying the method in different vehicles. Example 1
• Pigment CuO 40% , Fe 2 0 3 10% , Cr 2 0 3 30% , CoO 20%
• the laminate does not bubble.
• the darkness of the marking is good.
• the marking is sharp.
• the mechanical and chemical stabilities are good.
• the limits of the performance values (speed and current) are defined by the fact that the power density of the laser beam at the laminate may not be high enough to damage the laminate.
• Example 5 Marking of a windscreen with lead as the vehicle.
• This invention can be applied to make markings on glass by using the Nd/Yag type of laser, with the aid of a vehicle, through the glass on the lower surface thereof.
• Individualized markings of windscreens for example, such as the production and inspection markings related to the manufacture, as well as the body numbers or license numbers of cars intended for the identification the cars, can be made through the layers of glass and laminate on the lower surface (in the inside) of the windscreen and other glass.
• individual markings are typically limited by one marking head (galvohead) in the area of less than 350 mm x 350 mm.
• the usage possibilities of the method and device described above are not limited to the marking of windscreens, although this embodiment is used as an example to illustrate the application of the invention.
• the method and the device can be applied in all cases where individual markings should be done on transparent bodies in relatively small areas.
• the special glass needed in the chemical industry and biotechniques are major areas of application. The above-mentioned matters are also true for individual pieces manufactured on production lines.

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• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Surface Treatment Of Glass (AREA)
• Laser Beam Processing (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8540375

Family Applications (1)

Country Status (6)

Cited By (10)

Families Citing this family (9)

Citations (5)

Family Cites Families (12)

• 1994
  • 1994-03-24 FI FI941367A patent/FI103396B/fi active
• 1995
  • 1995-03-23 WO PCT/FI1995/000153 patent/WO1995025639A1/en active IP Right Grant
  • 1995-03-23 EP EP95913179A patent/EP0796174B1/en not_active Expired - Lifetime
  • 1995-03-23 DE DE69523774T patent/DE69523774D1/de not_active Expired - Lifetime
  • 1995-03-23 US US08/716,265 patent/US6442974B1/en not_active Expired - Fee Related
  • 1995-03-23 AU AU20742/95A patent/AU2074295A/en not_active Abandoned

Patent Citations (5)

Non-Patent Citations (1)

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