JP3915851B2 - Method for marking using a laser beam and method for marking identification information on a glass substrate in the manufacturing process of a display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for marking using a laser beam, and a method for marking identification information on a glass substrate in a manufacturing process of a display panel (for example, a plasma display panel), and more particularly to a marking object. The present invention relates to a method that enables marking using a laser beam without damaging an object.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, various types of identification information required for process management and the like are attached to a glass substrate (hereinafter simply referred to as a glass substrate) conveyed to a manufacturing process of a liquid crystal display panel. For example, as disclosed in JP-A-5-309552, as a means for attaching identification information, a method of attaching an identification label such as a barcode label (hereinafter referred to as a first method), a glass substrate side A method of making a small notch representing identification information at the edge and giving the identification information to the notch (hereinafter referred to as the second method), or a method of directly recording the identification information by laser processing on the glass substrate (hereinafter referred to as the second method) The third method) is known.
[0003]
However, in the first method described above, it is difficult to attach the barcode label depending on the manufacturing process. In the second method, the edge on the glass substrate side has low flatness, and it is difficult to read with a reading device or visually. In addition, dust is generated during recording, so a high cleanliness is required. It is difficult to use in the manufacturing process. Furthermore, in the third method, it is difficult to record clear information, and in addition, since the glass surface is scratched, if there is a heat treatment in the subsequent process, the scratch grows easily and breaks easily. Become.
[0004]
On the other hand, as a method for marking without damaging a transparent member such as glass, a marking method using a laser described in, for example, Japanese Patent Application Laid-Open No. 60-224588 is known. In this marking method, a glass plate as a marking object is stacked on a metal plate (or metal foil) as a coloring material, and this two-layered body is irradiated with a YAG laser beam from behind the glass plate as a marking object. However, the metal plate (or metal foil) that is the coloring material is heated by the laser beam that has passed through the marking object, and the metal evaporated or sublimated by the so-called laser sputtering principle is rebounded and adhered to the glass surface that is the marking object. The marking of a desired shape is performed.
[0005]
[Problems to be solved by the invention]
However, the conventional marking method using a laser beam has the following problems.
[0006]
First, since marking is performed by laser sputtering while irradiating a metal plate (or metal foil) that is a coloring material with a laser beam that has passed through the marking object itself, (1) the laser beam is not transmitted or It cannot be applied to marking objects that are difficult to transmit and are translucent or opaque to the laser beam. (2) Even if it is transparent to the laser beam, the marking object is too thick or distorted. Marking objects such as plasma display panels that have a SiO2 coating on the surface to prevent fluorescent lamp failure make it difficult to make fine markings due to the refraction of the laser beam and the resulting focus shift. Unsuitable for marking 2D barcodes that are on the way (3) Laser Bee However, it is not applicable to marking objects that are difficult to irradiate with a laser beam from behind the marking surface, such as when marking on the side of a CRT panel. There is a problem.
[0007]
Second, as a laser sputtering mechanism, the metal vapor that rises by heating and sublimation instantaneously by irradiating the metal plate as the coloring material is attached to the marking surface located in the direction opposite to the traveling direction of the laser beam. (1) Heating sublimation by laser beam irradiation because it adopts a structure that reminiscently (in other words, a structure reminiscent of the splash of water on the ceiling when a stone is dropped into a puddle on the floor) As a result, the rising metal vapor has a tendency to diffuse. As a result, no matter how narrow the laser beam diameter is, the line width to be marked is limited and is not suitable for fine marking. 2) The metal vapor that rises after being heated and sublimated by laser beam irradiation tends to be oxidized by the time it reaches the marking target surface. Because the elephants surface to adhere a significant amount of soot in addition to the marked line, that subsequent steps to wipe unwanted soot is essential, there are problems like.
[0008]
The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to relax restrictions on the thickness and material of the marking object and to use a laser beam without damaging the surface. It is to do fine marking.
[0009]
[Means for Solving the Problems]
The first invention of this application provides a transfer plate providing step for providing a transfer plate formed by depositing a colored film on one surface of a substrate having a property transparent to a laser beam;
A transfer plate superimposing step of superimposing the provided transfer plate so that the colored coating faces a desired position of a surface to be marked;
The superposed transfer plate is moved from behind with a laser beam while appropriately controlling the size of the fine gap between the transfer plate and the marking object so that there is a gap containing air. The colored coating on the transfer plate is transferred in a desired marking shape onto the surface to be marked by heating the colored coating with a laser beam that passes through the substrate while irradiating in accordance with the desired marking shape. A film transfer step,
A transfer plate removing step of removing the transfer plate from the surface to be marked;
A method for marking using a laser beam.
[0010]
The first invention is composed of four steps including a transfer plate providing step, a transfer plate overlaying step, a film transfer step, and a transfer plate removing step.
[0011]
In the transfer plate providing step, “a substrate having a property transparent to the laser beam” mainly defines the correlation between the wavelength of the laser beam and the material of the substrate. As is well known, when YAG laser light having a wavelength of 1.06 μm is used as the laser beam, glass having a property of transmitting YAG laser light can be used as the material of the substrate. In this case, the glass is not melted by the YAG laser beam. Thus, the material of the substrate can be appropriately selected according to the wavelength of the laser beam used, and is not necessarily limited to glass. However, heat resistance to such an extent that the colored coating described later is not melted during heating is required.
[0012]
Further, the “colored film” applied to one side of the substrate is heated by the laser beam irradiated through the above-mentioned substrate, is instantly evaporated or sublimated, and is transferred to the marking target surface by the principle of sputtering. Is. The selection of the material includes (1) a temperature characteristic that is heated by laser beam irradiation and instantly evaporates or sublimates, (2) has a necessary marking color, and (3) is uniform with respect to the substrate. It will be determined in consideration of the ability to form a thick film, (4) heat resistance to the processing temperature of the marking object, (5) availability at a relatively low cost, and the like.
[0013]
As the marking object, for example, assuming a glass substrate of a plasma display panel (PDP) or a plow tube for various monitors, and assuming a YAG laser beam as a laser beam and a glass plate as a substrate, a colored film As the material, for example, any one of (1) chromium, (2) tantalum, (3) an alloy of nickel and copper, etc. could be selectively employed. That is, with these materials, a film having a uniform thickness can be formed on the surface of the glass plate by vacuum deposition or sputtering, and at the same time, it is evaporated or sublimated by irradiation with a YAG laser beam, and sputtering is performed. In principle, clear marking can be performed on the glass surface, which is the marking target surface, and in addition, it can withstand the heat treatment temperature applied to the marking target object (because the melting point is higher than glass), and relatively Can be provided at low cost. Incidentally, the glass substrate of the PDP is charged and heated at least five times in a heating furnace of 500 degrees Celsius or higher in the subsequent manufacturing process following the marking. This is for a so-called rib forming process, a phosphor fixing process, and the like. Similarly, various types of monitor pipes are subjected to heat treatment one or more times in the subsequent manufacturing process following the marking. This is because the glass constituting the prawn tube is relatively thick so that the distortion needs to be removed. And if it is a colored film of the material of the above (1)-(3), there will be no possibility of a fusion | melting or dropping out also in those heat processing.
[0014]
Furthermore, the “colored film” does not necessarily have a single layer structure. For example, if it is a colored film having a two-layer structure in which a black first layer (lower layer) made of chromium oxide and a metal second layer (upper layer) made of chromium are sequentially stacked on a glass plate constituting the substrate, The presence of the chromium oxide layer (lower layer) suppresses the reflection of the chromium layer (upper layer) and at the same time increases the absorption efficiency of the laser beam, thereby enabling clear marking with a low light intensity laser beam. That is, the important point in the present invention is that a colored coating is applied to one side of a substrate having a property transparent to the laser beam, while the colored coating is applied by a substrate transmission laser by irradiating the colored coating from behind. In terms of evaporation or sublimation, as long as it is evaporated or sublimated, the colored film may have a single-layer structure or a two-layer structure.
[0015]
Next, in the transfer plate superposition step, “superimpose so that the colored coating faces each other” means that the surface of the colored coating and the surface to be marked face each other. Means. Of course, the meaning of “overlapping” here is, of course, an overlapping state in consideration of the normal surface accuracy of the coating surface and the surface to be marked, and air that does not have a 1 μm gap between them is also included. It does not mean that there is no complete close contact. That is, according to the sputtering principle of the present invention that performs marking by irradiating a colored material with a laser beam, evaporating or sublimating the material, and attaching the scattered material to the marking target surface, the colored film and the marking target The presence of a gap of at least about 1 μm between the surfaces will be essential. Taking the glass substrate of the previous PDP as an example, although the cleaning process has already been performed at the time of delivery, the surface accuracy is actually about 40 μm, no matter how flat the surface of the colored film is. When they are superposed, there should be a sufficient gap for sputtering between them.
[0016]
Further, in the film transfer step, “while irradiating with a laser beam corresponding to a desired marking shape” means that both a so-called one-stroke scanning and a raster scanning are included. Yes. Which one of the one-stroke writing method and the raster scanning method should be adopted may be selected according to the relationship with the laser beam intensity. In general, when the laser beam intensity is not so high, a one-stroke writing method that can concentrate the beam energy will be preferable. As is well known to those skilled in the art, in this one-stroke writing method, the wobbling method that fills the specified area while waving the beam like a circle while gradually shifting the center is slightly shifted in pitch. There is a filling method in which a prescribed region is filled with a large number of parallel lines.
[0017]
According to the first invention, if the surface to be marked is a relatively heat-resistant flat surface such as glass or ceramics, clear marking is performed without damaging the surface. Can do. Therefore, since dust is not generated during marking, it can be easily adopted in manufacturing processes that require high cleanliness, and the surface to be marked will not be scratched. There is no loss. Furthermore, with laser beam irradiation, it is possible to immediately perform line drawing processing along any marking shape with a high degree of freedom, so it is possible to quickly perform marking corresponding to any identification information. It becomes.
[0018]
In addition, since the colored film formed on the transfer plate is heated by a laser beam irradiated from behind, and this is instantly evaporated or sublimated, and transferred onto the marking target surface, (( 1) Needless to say, the present invention can be applied to a transparent marking object having a large thickness or distortion, or a marking object having a SiO 2 coating for preventing fluorescent lamp failure on a surface such as a recent plasma display panel. ) Applicable to marking objects that do not transmit or hardly transmit the laser beam and are translucent or opaque to the laser beam; (3) Behind the marking surface, for example, when marking on the side of a CRT panel. Can be applied to marking objects that are difficult to irradiate with a laser beam, and (4) By integer, that can control the quality of the marking, and has a conventional special effects not found in the laser marking method and the like.
[0019]
In addition, the evaporated or sublimated colored film component travels straight without being diffused while being pressed by the light pressure of the laser beam, and collides and adheres to the marking object surface placed in front of the laser beam traveling direction. (1) Fine and clear marking can be easily formed by narrowing the diameter of the laser beam. (2) Oxidation is difficult even when a metal such as chromium is used as a colored coating. Therefore, there is an extraordinary effect that is not found in conventional laser marking, such as the fact that there is little trouble in wiping.
[0020]
Here, the material of the substrate may be a material that is not melted by laser beam irradiation, and the material of the colored film may be a material that absorbs the laser beam that has passed through the substrate and is instantly evaporated or sublimated. . The material of the substrate and the colored coating constituting the transfer plate can be defined as follows. As described above, when glass is used as the substrate and a YAG laser is used as the laser beam, Cr can be used as the material of the colored film. When sputtering is used as a film forming technique, materials that can be applied to glass or plastic include Au, Pd, Ag, Cu, Cr, Al, Ta, Ni—Cr, TIN, TIC, ITO, and SiO 2. , Si3N4, Nb-Ti, Mo, Mo-Si, Co-Cr, Co-P, and the like. Therefore, among these candidate substances, the conditions (1) to (5) ((1) having temperature characteristics that are heated by laser beam irradiation to evaporate or sublimate instantaneously, and (2) necessary marking colors. (3) A film having a uniform thickness can be formed on the substrate, (4) It has heat resistance to the processing temperature of the marking object, (5) It can be provided at a relatively low cost, ) Can be selected as the material for the colored coating.
[0021]
According to a second invention of this application, in the first invention, the colored film is a material having a melting point higher than that of glass, and the marking object is a glass substrate or a cathode ray tube in a display panel manufacturing process. .
[0022]
The third invention of this application is characterized in that, in the first invention, the colored film is any one of Ag, Au, Cu, Cr, Al, Ta, Ni—Cr, and Mo.
[0023]
According to a fourth invention of this application, in the first invention, the colored film has a two-layer structure in which a lower layer and an upper layer are sequentially stacked on the substrate, and at the same time, the reflection of the upper layer is suppressed by the presence of the lower layer. The laser beam absorption efficiency is increased.
[0024]
Furthermore, here, the film transfer step may be performed while pressing the transfer plate against the surface to be marked and appropriately controlling the size of the fine gap formed between the two. As described above, since the marking method of the present invention uses the sputtering principle, it is necessary to have some gap between the colored coating and the marking target surface. According to the present inventors' diligent research, for example, when the YAG laser is used in combination with a glass substrate with a chromium coating and a PDP glass substrate, the size of the gap is required to be about 1 μm to 30 μm. Preferably, about 1 to 5 μm is considered optimal. On the other hand, the surface accuracy of the PDP glass substrate to be marked delivered from the glass manufacturer is about 40 μm, and the gap between the two may be too large just by placing the transfer plate on the PDP glass substrate. confirmed.
[0025]
Thus, the transfer plate is pressed against the surface to be marked, and the size of the fine gap formed between them is appropriately narrowed to improve the marking quality. In the pressing example performed by the present inventors, 20-30 gf / cm ² The transfer plate was pressed against the PDP glass substrate with a moderate pressure. By carrying out like this, a more reliable transfer can be performed by pressing the colored film applied to the transfer plate against the surface to be marked.
[0026]
Further, in the present application, when marking information on a glass substrate, a marking substrate is provided in the middle of a conveyance line in which a glass substrate used for a display panel is accommodated in a predetermined cassette and conveyed,
The marking processing station is provided with a cassette loader unit, an identification information recording unit, an identification information reading unit, and a cassette unloader unit,
In the cassette loader section, after taking the cassette from the upstream conveyance path, the glass substrate accommodated in the cassette loader section is taken out and sent to the identification information recording section, and an empty cassette is sent to the cassette unloader section. Done,
In the identification information recording unit, the identification information received from the identification information input communication port is recorded on the glass substrate sent from the cassette loader unit. Processing to send to the reading unit is performed,
The identification information reading unit reads the identification information recorded on the glass substrate sent from the identification information recording unit, and only when the glass substrate is determined to be normally recorded, the glass substrate Processing to send to the cassette unloader part is performed,
In the cassette unloader unit, the glass substrate sent from the identification information reading unit is again accommodated in an empty cassette sent from the cassette loader unit, and a process of sending it out to the downstream conveyance path is performed.
Furthermore, the recording of the identification information in the identification information recording unit,
A transfer plate providing step for providing a transfer plate formed by depositing a colored film on one side of a substrate having a property transparent to a laser beam;
A transfer plate overlaying step of overlaying the provided transfer plate so that the colored coating faces the desired position of the glass substrate to be marked;
By irradiating the transfer plate superimposed on the glass substrate from behind with a laser beam corresponding to the marking shape representing the identification information, by heating the colored film with a laser beam transmitted through the substrate, A film transfer step for transferring a colored film on the transfer plate onto a glass substrate to be marked in a desired marking shape;
A transfer plate removing step of removing the transfer plate from the glass substrate;
You may make it perform in the procedure which consists of.
[0027]
By adopting such a configuration, in the manufacturing process of display panels such as plasma display panels and liquid crystal display panels, clear and unique markings can be quickly made on individual glass substrates to be transported without scratching. It can be carried out.
[0028]
Here, the material of the substrate constituting the transfer plate is glass having a property transparent to YAG laser light, and the material of the colored film absorbs YAG laser light transmitted through the glass and instantly It may be a substance such as chromium which is evaporated or sublimated and whose melting point is higher than that of the substrate glass.
[0029]
By adopting such a configuration, it is particularly suitable for marking identification information on a glass substrate in a plasma display manufacturing process. As described above, the glass substrate for the plasma display uses a considerably thick glass plate (for example, 2.8 mm thick), and also has a silica coat (SiO2) for preventing fluorescent lamp failure on the surface thereof. In many cases, a coating) is applied. For this reason, in the method of transmitting a laser beam through the marking object itself as described in JP-A-60-224588, it is difficult to perform fine marking due to the influence of the refraction of the laser beam. Moreover, since this type of glass substrate is placed in a baking furnace at 500 degrees Celsius or more at least five times following the marking step, if it is damaged during marking, it grows upon heating, Glass may break. In contrast, the use of a YAG laser beam as the laser beam, and the use of glass and refractory materials such as chromium as the material of the substrate and the colored film constituting the transfer plate, damage the surface of the PDP glass substrate. Clear and heat-resistant markings (for example, one-dimensional or two-dimensional barcodes) can be applied without marking, and there is no risk of glass breaking during heat treatment, and the marks do not disappear during heat treatment. In addition, the mark does not disappear even in the etching and peeling process immersed in an acid / alkali solution, and the like has special effects.
[0030]
Furthermore, in the present invention, the film transfer step may be performed while pressing the transfer plate against a target glass substrate and appropriately controlling the size of the fine gap formed between the two.
[0031]
By adopting such a configuration, a more reliable transfer can be performed by pressing the colored film applied to the transfer plate against the surface to be marked.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0033]
As described above, in the marking method using the laser beam of the present invention, the transfer plate is formed by depositing a colored film on one side of a substrate having a property transparent to the laser beam. A transfer plate providing step for providing the transfer plate, a transfer plate superposing step for superposing the provided transfer plate so that the colored coating faces a desired position on the surface to be marked, and the superimposed transfer plate The colored coating on the transfer plate is desired on the surface to be marked by heating the colored coating with a laser beam that passes through the substrate while irradiating with a laser beam corresponding to the desired marking shape from behind. A coating film transfer step for transferring the marking plate with a marking shape, and a transfer plate removing step for removing the transfer plate from the surface to be marked. It is.
[0034]
Such a method for marking using a laser beam is used for various purposes. In this case, the method is used for marking identification information on a glass substrate in a manufacturing process of a display panel, particularly a plasma display panel. Explain the case.
[0035]
As is well known, in the manufacturing process of this type of plasma display panel, the glass substrate is accommodated in a predetermined cassette and transported. A marking processing station is provided in the middle of the transport line. The marking station thus provided is shown schematically in FIG.
[0036]
As shown in the figure, the marking processing station 1 is provided with a cassette loader section 2, an identification information recording section 3, an identification information reading section 4, and a cassette unloader section 5.
[0037]
In the cassette loader unit 2, after the cassette 6 is taken in from the upstream conveyor (upstream conveying path), the glass substrate 7 accommodated in the cassette loader 2 is taken out and sent to the identification information recording unit 3. Is sent out to the cassette unloader section 5.
[0038]
In the identification information recording unit 3, the identification information received from the identification information input communication port 8 is recorded on the glass substrate 7 sent from the cassette loader unit 2, and then the recording of the identification information is completed. Is sent out to the identification information reading unit 4.
[0039]
The identification information reading unit 4 reads the identification information recorded on the glass substrate 7 sent from the identification information recording unit 3 by using an identification information reader 9 such as a barcode reader, and is recorded normally. Only when it is determined that the glass substrate 7 is, the process of feeding the glass substrate 7 to the cassette unloader unit 5 is performed.
[0040]
In the cassette unloader unit 5, the glass substrate 7 sent from the identification information reading unit 4 is accommodated again in the empty cassette 6 sent from the cassette loader unit 2, and is then transported to the downstream conveyor (downstream transport path). The process to send to is performed.
[0041]
In FIG. 1, 17 is an operation panel for controlling the equipment of the entire station, and 18 is a supply port for the transfer plate 13.
[0042]
Next, the identification information recording process in the identification information recording unit 3 which is the main part of the present invention will be described in detail with reference to FIG. 2 and FIG.
[0043]
In this identification information recording step, first, as shown in FIG. 2A and FIG. 3A, a 0.7 mm thick glass plate (for example, a substrate having a property transparent to a YAG laser beam) , Soda lime glass) 11 is prepared, and a chromium film 12 which is a heat-resistant colored film (melting point 1600 degrees Celsius) is deposited on one surface thereof to a uniform thickness of about 180 nm by vacuum deposition or sputtering technique. The transfer plate 13 is provided. 2 and 3, the transfer plate 13 has a chrome coating 12 applied to the lower surface thereof.
[0044]
In addition, as the glass plate 11 which comprises the transfer plate 13, the glass plate (for example, soda-lime glass, an alkali free glass, anti-strain glass etc.) of a normal material can be used. Further, the thickness of the glass plate 11 constituting the transfer plate 13 is preferably thin in consideration of the influence of refraction of the laser beam, etc., but if it is too thin, it is divided by the heat when the chromium film 12 evaporates or sublimates. Since there exists a possibility, it is thought that the range of about 0.5 mm-2.0 mm is preferable. Further, the thickness of the chromium coating 12 may be appropriately set according to the marking quality, but it is considered that the range of 100 nm to 200 nm is preferable in practical use.
[0045]
Next, the transfer plate 13 thus provided is placed on a desired position of a PDP glass substrate (for example, 2.8 mm thick) 7 to be marked so as to face the chrome coating 12. To do. At this time, as necessary, the transfer plate 13 may be pressed onto the PDP glass substrate 7 with an appropriate pressure P as shown in FIG.
[0046]
That is, as described above, since the marking method of the present invention uses the sputtering principle, there must be a certain gap between the colored coating and the marking target surface. According to the present inventors' diligent research, for example, when the YAG laser is used in combination with a glass substrate with a chromium coating and a PDP glass substrate, the size of the gap is required to be about 1 μm to 30 μm. Preferably, about 1 to 5 μm was found to be optimal. On the other hand, the surface accuracy of the PDP glass substrate to be marked delivered from the glass maker is actually about 40 μm at the time of delivery, and simply placing the transfer plate 13 on the PDP glass substrate 7 It was confirmed that the gap between them was too large.
[0047]
Therefore, in this embodiment, the transfer plate 13 is pressed against the PDP glass surface to be marked, and the size of the fine gap formed between the two is appropriately narrowed to improve the marking quality. In the pressing example performed by the present inventors, 20-30 gf / cm ² The transfer plate was pressed against the PDP glass substrate with a moderate pressure.
[0048]
Next, as shown in FIG. 2A and FIG. 3A, a YAG laser beam (wavelength: about 1.06 μm) is transmitted through the lens system 10a using the YAG laser marker device 10 disposed above the transfer plate 13. 14 is emitted, and the transfer plate 13 superimposed on the PDP glass substrate 7 is formed into a marking shape representing the identification information with a laser beam 14 from behind (that is, from the exposed surface side of the glass without the chromium coating 12). The chromium film 12 is heated by the laser beam 14 transmitted through the glass plate 11 while correspondingly irradiating, and this is instantly evaporated or sublimated, so that the chromium film on the transfer plate 13 is formed on the principle of laser sputtering. 12 is transferred to the surface of the PDP glass substrate 7 to be marked in a desired marking shape.
[0049]
Here, as is well known (see, for example, Japanese Patent Application Laid-Open No. 6-8634), the laser marker device 10 is capable of oscillating a thinly focused laser beam 14 in an arbitrary locus. The beam irradiation trajectory is arbitrarily controlled by the given identification information.
[0050]
As the irradiation locus of the laser beam 14, a so-called one-stroke writing method and a raster scanning method can be considered. Which one of the one-stroke writing method and the raster scanning method should be adopted may be selected according to the relationship with the laser beam intensity. In general, when the laser beam intensity is not so high, a one-stroke writing method that can concentrate the beam energy will be preferable. As is well known to those skilled in the art, in this one-stroke writing method, a wobbling method in which a prescribed area is filled while a beam is swung in a circle while gradually shifting the center (see FIG. 4A). ) And a filling method (see FIGS. 4B and 4C) in which a predetermined region is filled with a large number of parallel lines while slightly shifting the pitch. In general, the method shown in FIG. 4A is used for bold drawing, the method shown in FIG. 4B is used for bar drawing, and the method shown in FIG. 4C is used for normal character drawing. On the other hand, when the raster scan method is adopted, a number of parallel scans are performed while shifting the laser beam 14 in the width direction along the longitudinal direction of the transfer plate 13 while appropriately blinking the laser beam 14. Form a trajectory. As a result, on the upper surface side of the PDP glass substrate 7 in the drawing, the chromium film 12 instantly evaporated or sublimated by the irradiation of the laser beam 14 is transferred as it is by the principle of laser sputtering.
[0051]
Next, as shown in FIG. 2B, when the transfer plate 13 superimposed on the PDP glass substrate 7 is lifted and removed, the transfer chrome coating 12 a remains at a predetermined position on the PDP glass substrate 7. It is. If the desired marking shape is a bar code mark 16 as shown in FIG. 3B, a transfer chrome coating 12a is drawn on the upper surface side of the glass substrate 7 from which the transfer plate 13 has been removed. The bar code mark 16 is left.
[0052]
In the identification information storing step described above, the laser beam 14 emitted from the YAG laser marker device 10 is directed to draw an appropriate trajectory, and the transfer plate 13 superimposed on the PDP glass substrate 7 is irradiated from behind. As a result, the chromium film 12 is instantly evaporated or sublimated and transferred onto the glass substrate 7, so that the surface of the PDP glass substrate 7 is damaged while using the laser beam 14. The clear marking on the surface can be performed quickly. Therefore, according to this method, since dust is not generated during the marking operation, the marking operation can be performed without any trouble in the manufacturing process of the plasma display panel that requires a high degree of cleanliness. Therefore, there is no risk that the PDP glass substrate will be cracked during the heat treatment associated with the phosphor fixing process and the rib manufacturing process.
[0053]
Furthermore, since directivity control of the laser beam 14 using the laser marker device 10 has a very high degree of freedom by a known mechanism, any identification information received during the manufacturing process is immediately marked on the surface of the PDP glass substrate 7. It is possible to improve the degree of freedom of process management.
[0054]
In addition, since the marking formed on the surface of the glass substrate 7 is made of the transfer chromium film 12a, the transfer chromium film 12a may be peeled off even if the PDP glass substrate 7 is shifted to the chemical treatment or heat treatment process. There is no drop off, and there is no restriction on its use as in the case of using a conventional bar code label, and the transfer chromium film 12a has a visual reading recognition rate on the surface of the glass substrate 7. It is very high and has effects such as being suitable not only for machine reading but also for reading by the human eye.
[0055]
In the above embodiment, the plasma display panel is taken as an example of the display panel and the glass substrate is marked. However, the same applies to other display panels having a glass substrate such as a liquid crystal display panel. . Further, although a glass plate is used as a substrate transparent to the laser beam, other high heat resistant plastics may be used. Further, the material of the colored coating is not limited to chromium, but other tantalum, copper-nickel alloy, or the like can be used. Further, in the above embodiment, the present invention has been described in the case of marking on glass. However, any other plane having relatively heat resistance and flatness, such as a ceramic plate or a metal plate. Can be selected as a marking target.
[0056]
【The invention's effect】
As is clear from the above description, according to the present invention, if the surface to be marked is a flat surface having relatively heat resistance such as glass or ceramics, it is clear without scratching the surface. Marking can be performed. Therefore, since dust is not generated during marking, it can be easily adopted in manufacturing processes that require high cleanliness, and the surface to be marked will not be scratched. There is no loss. Furthermore, with laser beam irradiation, it is possible to immediately perform line drawing processing along any marking shape with a high degree of freedom, so it is possible to quickly perform marking corresponding to any identification information. It becomes.
[0057]
In addition, since the colored film formed on the transfer plate is heated by a laser beam irradiated from behind, and this is instantly evaporated or sublimated, and transferred onto the marking target surface, (( 1) Needless to say, the present invention can be applied to a transparent marking object having a large thickness or distortion, or a marking object having a SiO 2 coating for preventing fluorescent lamp failure on a surface such as a recent plasma display panel. ) It can be applied to marking objects that are not or hardly transmit the laser beam and are translucent or opaque to the laser beam. (3) From behind the marking surface, for example, when marking on the surface of a cathode ray tube. Applicable to marking objects that are difficult to irradiate with a laser beam. (4) Adjust the thickness of the colored coating. It makes it capable of controlling the quality of the marking, and has a conventional special effects not found in the laser marking method and the like.
[0058]
In addition, the evaporated or sublimated colored film component travels straight without being diffused while being pressed by the light pressure of the laser beam, and collides and adheres to the marking object surface placed in front of the laser beam traveling direction. (1) Fine and clear marking can be easily formed by narrowing the diameter of the laser beam. (2) Oxidation is difficult even when a metal such as chromium is used as a colored coating. Therefore, there is an extraordinary effect that is not found in conventional laser marking, such as the fact that there is little trouble in wiping.
[0059]
This point is further illustrated and described. A conventional laser marking method described in JP-A-60-224588 is shown in FIG. 5A, and the laser marking method of the present invention is shown in FIG. 5B. In these figures, the gap between the marking target surface and the transfer material surface is enlarged or exaggerated. As is apparent from these drawings, in the conventional laser marking method, as shown in FIG. 5A, as a laser sputtering mechanism, the metal plate 19 serving as a coloring material is irradiated with the laser beam 20. In this configuration, the metal vapor 21 that is heated and sublimated instantaneously and adheres to the surface 22a of the marking object 22 located in the direction opposite to the traveling direction of the laser beam (in other words, the stone is put in the puddle on the floor surface. (1) The metal vapor that rises by heating and sublimation by laser beam irradiation has a tendency to diffuse, as a result. No matter how narrow the laser beam diameter is, the line width marked by it is limited, and it is not suitable for fine marking. (2) The metal vapor that rises by heating and sublimation by the beam irradiation has a tendency to be oxidized before reaching the marking target surface, and a considerable amount of soot adheres to the marking target surface in addition to the marked lines. There are problems such as the necessity of a post-process for wiping off the soot.
[0060]
On the other hand, in the laser marking method of the present invention, as shown in FIG. 5B, the vapor 21 that is the colored film component 23 evaporated or sublimated is pressed against the light pressure of the laser beam 20. In this case, the laser beam goes straight without diffusing so as to collide and adhere to the surface 22a of the marking object 22 placed in front of the laser beam traveling direction. (1) By narrowing down the diameter of the laser beam, it is fine and clear. Conventional lasers that can easily form markings, and (2) that they are not easily oxidized even when a metal such as chromium is used as a colored coating, that there are few wrinkles and no wiping work is required. It has a special effect not found in marking. Reference numeral 24 denotes a glass plate constituting the transfer plate.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a layout of a marking processing station for marking identification information in a manufacturing process of a plasma display panel.
FIG. 2 is a schematic process diagram for explaining an identification information recording process in an identification information recording unit.
FIG. 3 is an explanatory diagram showing a relationship between a film transfer step and a transferred marking shape.
FIG. 4 is a diagram showing an example (so-called one-stroke writing method) of an irradiation locus of a laser beam at the time of marking.
FIG. 5 is an enlarged view of a conventional laser marking method described in Japanese Patent Application Laid-Open No. 60-224588 and the laser marking method of the present invention in an enlarged or exaggerated manner at a gap portion between a marking target surface and a transfer material surface. It is.
[Explanation of symbols]
1 Marking station
2 Cassette loader section
3 Identification information recording part
4 Identification information reader
5 Cassette unloader section
6 cassettes
7 PDP glass substrate
8 Communication port for input of identification information
9 Identification information reading
10 Laser marker device
11 Glass plate
12 Chrome film
12a Transfer chrome film
13 Transfer plate
14 Laser beam
15 Transport roller
16 Bar code mark
17 Operation panel
18 Transfer plate supply port
19 Metal plate that is a coloring material
20 Laser beam
21 Steam of coloring material
22 Marking object
22a Surface of marking object
23 Colored film as coloring material
24 Glass plate constituting the transfer plate

Claims (4)

A transfer plate providing step for providing a transfer plate formed by depositing a colored film on one side of a substrate having a property transparent to a laser beam;
A transfer plate superimposing step of superimposing the provided transfer plate so that the colored coating faces a desired position of a surface to be marked;
The superposed transfer plate is moved from behind with a laser beam while appropriately controlling the size of the fine gap between the transfer plate and the marking object so that there is a gap containing air. The colored film on the transfer plate is transferred in a desired marking shape onto the surface to be marked by heating the colored film with a laser beam that passes through the substrate while irradiating in accordance with the desired marking shape. A film transfer step,
A transfer plate removing step of removing the transfer plate from the surface to be marked;
A method for marking using a laser beam. The colored film is a material having a melting point higher than that of glass,
The method for marking using a laser beam according to claim 1, wherein the object to be marked is a glass substrate or a cathode ray tube in a display panel manufacturing process . The method for marking using a laser beam according to claim 1, wherein the colored coating is one of Ag, Au, Cu, Cr, Al, Ta, Ni-Cr, and Mo. The colored film has a two-layer structure in which a lower layer and an upper layer are sequentially stacked on the substrate, and the reflection of the upper layer is suppressed by the presence of the lower layer, and at the same time, the absorption efficiency of the laser beam is increased. A method for marking using the laser beam described in 1.

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