KR20120107505A - Method and apparatus for applying a perforation in an initially flat laminated substrate wherein the substrate is flat after irradiation and a possible posttreatment - Google Patents

Abstract

The present invention relates to a method and apparatus for perforating flat laminated substrates, such as cards having a thickness of at least 0.2 mm, by irradiating the substrate with a laser. If such a card is punched by a laser, it is often warped, leading to handling problems in subsequent processing steps. The present invention may relate to a substrate forming part of a booklet such as a passport. According to the invention, the substrate is flattened after irradiation and possible post treatment. According to the first embodiment, the characteristics of the laser irradiation process are selected so that the substrate becomes flat after irradiation. According to the second embodiment, the substrate is flattened after laser irradiation, for example by heating the substrate.

Description

Method and apparatus for applying a perforation in an initially flat laminated substrate where the substrate is flat after irradiation and a possible posttreatment}

The present invention relates to a method and apparatus for irradiating a substrate with a laser to pierce an initially flat laminated substrate having a thickness of at least 0.2 mm.

In the past few years, the use of lasers to personalize identification documents such as passports and driver's licenses has increased. Such personalization may relate to the application of a personalized number identification document or to applying a hole pattern representing a passport picture of a bearer to make counterfeiting of these documents more difficult. This improves the safety and reliability of these documents. EP-A-0 936 975 is provided with documents and devices provided with such features and methods for personalizing these documents.

Often the holes can be drilled in a card of laminated material having a thickness of at least 0.2 mm. These cards are also provided with other personalized features such as the holder's name, address, date and place of birth and passport photo. Such a card may form a personalized document on itself, but it may also form part of a large document, such as a passport booklet, in which the personalized card includes several pages of one of the pages. It is noted that such stacked cards can be counterfeit and tampered by adding personalized features to the card in the form of holes. If a hole is punched into a card by a laser, the cards are often bent, leading to handling problems in the next processing steps of the card. In addition, the warped and deformed card is not considered to be a high quality product, causing a conflict with the very nature of the identification documents.

It is an object of the present invention to provide a method and apparatus for avoiding these problems.

This object is achieved by means of irradiating a substrate with a laser to pierce an initially flat laminated substrate having a thickness of at least 0.2 mm, which is achieved by a substrate puncture method in which the substrate is flattened after irradiation and possible post treatment.

A corresponding apparatus for punching an initially flat laminated substrate having a thickness of at least 0.2 mm includes an irradiation support member for supporting the substrate during irradiation, a laser unit for irradiating the substrate to puncture the substrate, and The device is adapted to carry a flat perforated substrate.

Often the substrate forms part of a booklet. In such a situation, the remaining pages of the booklet are preferably folded so that the substrate is accessible from at least one side.

Thus, the apparatus is adapted to perforate the substrate forming a portion of the booklet, the apparatus comprising holding means for holding the remaining pages of the booklet in a folded state when the substrate is above the substrate carrier such that the substrate is accessible from at least one side ( holding means).

A first possibility to reach this purpose is by the application of a laser irradiation process and the corresponding device in which the characteristics of the laser are selected so that the substrate is flattened after irradiation.

The same embodiment therefore provides a device of the kind mentioned above in which the laser has a wavelength of substantially 9.3 μm when in polycarbonate.

More specific embodiments provide the feature that the wavelength of the laser is substantially 9.3 μm when the substrate is polycarbonate.

An alternative possibility is to use a method in which the substrate is flattened after irradiation with a laser.

According to a preferred embodiment, the substrate is flattened by heating the substrate.

Embodiments also provide an apparatus comprising at least one heated temperature control plate movable between a non-operational position and a heating position adapted to be in contact with a substrate on a heating support member.

The substrate is preferably heated by contacting at least one side of the substrate with the heated temperature control body, but it may also be possible for the substrate to be heated by contacting both sides of the substrate with the heated temperature control body.

Thus, the same embodiment includes at least one heated temperature control plate movable between a non-operational position and a heating position such that the heating station is adapted to contact the substrate over the heating support member, or alternatively the heating station is in the non-operational position. And two heating temperature control plates each movable between an operating position where the substrate on the heating support member is fixed between both plates.

As an alternative to heating by heated plates, it is possible for the substrate to be heated by IR radiation.

This leads to the heating station comprising an IR-source adapted to irradiate the substrate on the heating support.

The heating is not excluded from occurring above the same position as the irradiation with the laser, and in order to increase the throughput, the substrate is preferably transferred between the irradiation with the laser and the heating.

Another preferred embodiment provides the feature that the heating member comprises two flat temperature control plates that are movable between a non-operational position and a heating position in which the substrate is fixed between both plates.

Another preferred embodiment is such that the conveying means conveys the substrate from the support to the heated position, wherein the retaining means does not fold the pages of the booklet over the substrate when the substrate is in the heated position such that the substrate is accessible to the heating plates from both sides. Provide features that are intended to be maintained.

The invention will next be described with the aid of the accompanying drawings.
1 is a cross-sectional view of a laser drilling apparatus according to the prior art.
2 is an elevational view of the laser drilling apparatus shown in FIG. 1 to which a heating device according to the invention is added.
3 is a side view of the apparatus shown in FIG. 2;
4 is a sectional view of the device shown in FIGS. 2 and 3;

The device shown in FIG. 1 shows a longitudinal support 1 in which documents 2 to be provided with laser drilling are conveyed in the longitudinal direction of the support 1. In order to drive these documents 2, a pair of drive belts 3 are provided on the longitudinal support 1. These drive belts 3 are each wound around two pulleys 4, at least one of which can be driven by an electric motor not shown in the figures. By driving the belts 3, the documents 2 are driven along the longitudinal support. The apparatus also includes a laser unit 5 represented by a rectangle. It will be apparent to those skilled in the art that the laser unit 5 comprises means for deflection and control of the laser source and the laser beam 6 exiting from the laser source 5. The apparatus also comprises a control unit, which is not shown in the figures, but which is adapted to control the movement of the belts 3, hence the document 2 and the laser unit 5.

The devices so far belong to the prior art. Therefore, a problem arises in which the document 2 is no longer completely flat after being perforated by a laser. In other words, it may be forced into a flat shape, but it may include internal stresses that cause the document 2 to return to its jaw shape if the document 2 does not yield to external forces. These stresses are generated by the thermal energy supplied by the laser to the document during the drilling by the laser.

According to the first embodiment, the characteristics and control of the laser are modified such that the transfer of heat to the document is minimized so that only the energy necessary to perform the actual perforation is transferred to the document. This can be done using a laser having a wavelength that is optimally absorbed by the material to be treated. For example, when using a polycarbonate substrate, a wavelength of 9.3 μm is absorbed better than a more common wavelength of 10.6 μm. As a result, the 9.3 μm wavelength does not bend the substrate, while the 10.6 μm wavelength bends.

In addition, the document may be a single card, such as a driving license, but it may also be formed by a card that is part of a booklet such as a passport. In such cases, the conveying means and belts comprising the longitudinal support must be adapted for the transport of the document in booklet form. In particular, pages of the booklet other than the card will be folded to allow the laser to reach the card for punching, so that the conveying means must be adapted to transport such documents.

Another solution to the warped card problem is to heat the card to release the stress on the card. Therefore, the second embodiment of the present invention includes a heating member for heating the card to remove stresses generated by the local application of heat of the puncture laser.

A corresponding embodiment is shown in FIG. 2. Here, the support 1 appears to consist of three support rails 1a, 1b, 1c into which the document 2 can be conveyed. Here, the outer rails are approximately L-shaped to allow proper guidance of the document 2. The document 2 also consists of an actual document 2a provided with a personalized perforation and folded pages 2b to allow the card 2a to be reached by the laser beam 6. Three belts 3a, 3b, 3c are also located above the rails 2 for transporting documents in the longitudinal direction of the support. The position of the belts 3a, 3b, 3c in the width of the support here is chosen such that the card 2a is accessible to the laser beam 6. After the laser drilling has taken place, the folded document 2 is further transported along the support 1 in its longitudinal direction. Although it is possible to stop the document during laser drilling, it is also possible to carry out laser processing during the movement of the document 2.

Following laser drilling, the document is moved to a heating member comprising two heating plates 10, of which only the upper heating plate 10a of the heating plates can be seen in FIG. 2. In FIG. 3 both heating plates 10a and 10b can be seen together with the document 2 located between the two heating plates 10a and 10b.

As can be seen in FIG. 4, the lower heating plate 10b is fixed relative to the support 1, while the upper heating plate 10a is pivotally connected to the support 1. This pivotable connection allows two heating plates to allow intimate contact between the document and the heating plates 10a, 10b and its non-active position where the upper heating plate 10a is capable of moving the document 2. Allows turning between enclosed working heating positions between the fields 10a and 10b. As mentioned above, the laser perforated document 2 is conveyed to a position between the two heating plates when the heating plate 10a is in its upper non-operational position. When the document reaches this position, the upper heating plate 10a is moved to its lower position and the document is clamped between the heating plates 10a and 10b. The heating plates are kept constant at a certain adjustable temperature controlled by a control loop consisting of a temperature sensor, heating element and control electronics. Heating and subsequent cooling of the document 2 leads to the release of the internal mechanical stresses in the material of the document 2, as a result of which it takes back its flat shape. After heating of the document, the upper heating plate is raised to its upper, non-operational position and the document 2 is further transported for further processing. During this further transfer it cools down.

It is noted that the heating takes place by contact between the heating bodies 10 and the document 2. It is conceivable that the same effect can be achieved by other heat transfer means. However, an advantage of the method of using contact heat is that it coincides with the pressing of the document 2 into a flat shape requiring the application of heat, and as a result flattening of the document is promoted.

Claims (19)

A method of puncturing an initially flat laminated substrate having at least 0.2 mm thickness by irradiating the substrate with a laser, wherein the substrate is flattened after irradiation and possible posttreatment. The method of claim 1,
Wherein the method is applied to a substrate forming a portion of the booklet and the remaining pages of the booklet are folded so that the substrate is accessible from at least one side. The method according to claim 1 or 2,
Characteristics of the laser irradiation process are selected such that the substrate is flattened after the irradiation. The method of claim 3, wherein
Wherein the wavelength of the laser is substantially 9.3 μm when the substrate is polycarbonate. The method according to claim 1 or 2,
And the substrate is flattened after the irradiation with a laser. The method of claim 5, wherein
And the substrate is flattened by heating the substrate. The method according to claim 6,
And the substrate is heated by contacting at least one of the substrates with a heated temperature controlled body. The method of claim 7, wherein
And the substrate is heated by contacting both sides of the substrate with a heated temperature control body. The method according to claim 6,
And the substrate is heated by IR radiation. 9. The method according to any one of claims 6 to 8,
And the substrate is transferred between the irradiation with a laser and the heating. An apparatus for drilling an initially flat laminated substrate having a thickness of at least 0.2 mm, comprising an irradiation support member for supporting the substrate during irradiation, and a laser unit for irradiating the substrate to puncture the substrate. To
And the device is adapted to carry a flat perforated substrate. The method of claim 11,
The apparatus is adapted to perforate a substrate forming a portion of the booklet, the apparatus retaining means for retaining the remaining pages of the booklet in a folded state when the substrate is over a substrate carrier such that the substrate is accessible from at least one side. substrate holding device, characterized in that it comprises a holding means. 13. The method according to claim 11 or 12,
Wherein the laser has a wavelength of substantially 9.3 μm when the substrate is polycarbonate. 13. The method according to claim 11 or 12,
The apparatus comprises a heating station adapted to heat the substrate after the substrate has been irradiated while the substrate is supported by the heating support means and for transferring the substrate from the irradiation support member to the heating support member. Substrate perforation device, characterized in that it comprises transport means. 15. The method of claim 14,
And the heating station comprises at least one heated temperature control plate movable between a non-operational position and a heating position adapted to contact the substrate on the heating support member. The method of claim 15,
And the heating station comprises two heating temperature control plates, each movable between an inoperative position and an operating position in which the substrate above the heating support member is fixed between both plates. 15. The method of claim 14,
And the heating station comprises an IR-source adapted to irradiate the substrate on the heating support. The method according to any one of claims 14 to 17, wherein
And the holding means is adapted to hold the pages of the booklet so as not to be folded over the substrate when the substrate is on the heating support such that the substrate is accessible to the heating means. The method of claim 18, wherein the method is dependent on claim 16.
And the holding means is adapted to hold the pages of the booklet so that they are not folded over the substrate when the substrate is on the heating support such that the substrate is accessible from both sides thereof.

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