GB2407798A

GB2407798A - Production of two sided microdots

Info

Publication number: GB2407798A
Application number: GB0418274A
Authority: GB
Inventors: Michael Moizer
Original assignee: MICRO TAG TECHNOLOGIES Ltd
Current assignee: MICRO TAG TECHNOLOGIES Ltd
Priority date: 2003-11-05
Filing date: 2004-08-16
Publication date: 2005-05-11
Anticipated expiration: 2024-08-16
Also published as: GB0325872D0; GB2407798B; GB0418274D0

Abstract

Film 10 is etched to form characters in both sides of the film. The film 10 may be of a material which reacts to light to cause local burning, such as a polycarbonate foil. The film 10 may be etched by steerable beam lasers 14,15 on opposite sides of it. The same characters may be formed on both sides. Once the characters are formed, the separator 18 cuts or punches the microdots from the rest of the film 10. They are bottled with resin or adhesive using bottling system 21. The characters may be viewed by cameras 16,17.

Description

Production of Microdots The present invention relates to the production of

microdots. It also relates to a microdot when produced by such a method.

Microdots are very small bodies, usually circular and in the form of a thin film, on which text or other information is marked. The dots are then stuck to objects such as computers and other household and office goods, so that the object can be identified by reading the information on the microdot if the object if lost or stolen. This enables the object to be returned to its proper owner.

Existing microdots are formed by printing the information onto a surface of suitable translucent film using ink-based techniques. However, such microdots have disadvantages. Firstly, the fact that the information is printed on only one side of the film means that the information will usually not be readable unless the microdot is the right way up on the object. Secondly the ink tends to degrade on exposure to the adhesive used to attach the dots, so that when attaching the microdot to an object the ink may be smudged making the microdot unreadable. Fading of the ink due to exposure to light may occur after the microdot has been applied to the object. Reading the dots on shiny surfaces can be difficult because of light scattered by the surface behind the dot.

At its most general, and in a first aspect, the present invention proposes that microdots are formed in which the information is recorded on both sides of the film forming the dot, and the formation of the information is carried out by an etching process.

Preferably, the etching is carried out using light (e.g. from a suitable laser or lasers), and the etching is such as to cause a visible or otherwise optically readable change in the appearance of the film. The information to be recorded may thus be produced by moving a corresponding light beam or beams, preferably laser, over the film.

According to a second aspect of the invention it is proposed that microdots are recorded on both sides of the film forming the dot, and the formation of the information is carried out by a process which causes local burning of the material of the film. Again, the local burning may be achieved by light, e.g. laser beams.

According to a third aspect of the invention there is provided a method of forming microdots, comprising recording information both sides of a film of material, the recording of the information being carried out by a process causing a physical or chemical change in the film, and cutting the film to separate the microdots, wherein the information is recorded simultaneously on both sides of the film.

The film from which the microdots are produced may be supplied in continuous form, with the part of that continuous film which is to form microdots then being punched or otherwise removed from the rest of the film.

The recording of the information is typically carried out before the removal of the microdots from the rest of the film. This makes the handling of the microdots easier during the recording of the information, since they are at that time still part of the film. It is desirable to have an arrangement for checking that the information has been recorded in the correct position, before the microdots are removed from the rest of the film.

It is also desirable for the film to be accurately guided and indexed during the recordal of the information and the removal of the microdots from the rest of the film.

Preferably, there are recording beam sources e.g. lasers on each side of the film, to enable the information to be recorded on both sides of the microdot simultaneously.

After they have been punched from the rest of the film, the microdots may be put in a bottle or other container, containing suitable resin or other adhesive to enable them to be attached to objects. They may be prepared so that they can be applied as an aerosol type spray. For convenience, each microdot in such a container may have the same information, with the information of microdots in different containers being different. Information in the container may be identified by e.g. a label on the container itself.

Although the invention has been described above in terms of the method of manufacture of the microdots, the present invention also relates to a microdot when produced by such a method, and apparatus for making the microdots.

The size and shape of the microdots is not critical to the present invention, but typically the microdots are circular with a diameter of e. g. from 0.7 - 1.5 mm.

An embodiment of the present invention will now be described in detail, by way of example, with a reference lO to the accompanying drawing, in which the sole figure shows a method of producing microdots according to the present invention.

Referring to the figure, a film 10 from which the microdot will be produced is drawn from a reel 11. The film is opaque. It may be e.g. a polycarbonate foil having a thickness of 100 Em and being 50 mm wide. The foil passes between two indexing mechanisms 12,13 which cause the film 10 to be conveyed between the mechanisms 12,13 in a series of steps which are accurately indexed so that the position of the film is determined precisely at all times. A suitable mechanism is by a series of punched indexing holes down the film edge, engaged by a hitch drive. Suitable guides (not shown) are provided to ensure that the film 10 between the mechanisms 12,13 is suitably supported.

Two lasers 14,15 are provided on each side of the film 10 downstream of the first index mechanism 12. The lasers 14,15 each generate a beam of light incident on the film 10, the beams being steerable so that they follow a suitable path on the film. The film 10 is etched by the laser light to generate e.g. a dark mark.

The etching results in a local burning of the material. s

Thus, as the beams are steered on the film, alphanumeric or other characters or codes may be recorded on the film.

The lasers and the film material are selected and adjusted so that the film can be marked on both sides while maintaining structural integrity. Depending on the materials this may involve precautions such as the use of "crossless" character fonts, which avoid the laser passing twice over the same piece of film when forming a character. Preferably the laser is a YAG laser such as a Rofin Sinar Powerline Laser. The locations of the lasers 14,15 above and below the film should be aligned accurately relative to each other and the film, to ensure that the beam from each laser 14,15 is accurately focused on the film, and that the positions of recordal of the characters on each side of the film are precisely aligned. In order to ensure that the characters have been recorded properly, cameras 16,17 may be provided above and below the film 10, downstream of the lasers 14,15 to enable the characters which have been recorded on the film to be viewed.

The characters are recorded in a small area on the film, which will correspond to one microdot. Multiple such recordals may be provided across the film, to enable multiple microdots to be produced on the film during each step of the film between the index mechanisms 12,13.

The film then passes through a separator 18 which separates the microdots from the rest of the film. This may be achieved by e.g. punching the microdots from the film, although it may also be possible to use laser cutting of the film. Film from which the microdots have been removed is then waste material 19, although a further camera 20 may be provided to inspect that waste material to ensure that the microdots have been removed correctly, i.e. there is no remaining information recorded on the waste material.

Alignment of the laser-recorded information with the mechanical or laser punch is important. We use the laser to make a periodic indexing mark on the film strip, e.g. one mark per 50 dots, this mark then being detected at the punch device and used to assure alignment.

The microdots that have been separated by the separator pass to a bottling system 21. In that system, a batch of microdots are put into a suitable bottle or other container, and the bottle at least partially filled with resin from a suitable dispenser 22. A label may be applied to the bottle by a suitable printer 23 e.g. to identify the characters that are on the microdots in that bottle. It is convenient if all the microdots in a given bottle have the same characters thereon. This can be achieved by operating the system shown in the figure in a batch manner, which a batch of microdots are produced with the same characters, and all which go into a common bottle at the bottling system 21 and then the pattern of movement of the beams of the lasers 14,15 is changed to write different characters on the next batch of microdots. The batch may be e.g. of the order of 500 microdots. Each microdot is then a 1.25 mm diameter circle of foil material, carrying e.g. 23 characters on each side thereof. t

Claims

Claims 1. A method of forming microdots, comprising: recording information

both sides of a film of material, the recording of the information being carried out by an etching process; and cutting the film to separate the microdots.
2. A method according to claim 1 wherein the information is recorded using light, and the film is of a material which reacts to light to cause local burning of the material of the film.
3. A method of forming microdots, comprising: recording information both sides of a film of material, the recording of the information being carried out by a process which causes local burning of the film; and cutting the film to separate the microdots.
4. A method according to any one of claims 1 to 3, wherein the microdots are cut by punching from the film.
5. A method according to any one of the preceding claims, wherein the information is recorded simultaneously on both sides of the film.
6. A method according to any one of the preceding claims, wherein the information recorded is the same as both sides of the film.
7. A method according to any one of the preceding claims wherein the cut microdots are put in a container, which container also contains adhesive.
8. An apparatus for forming microdots comprising: means for transporting a film of material along a transport paths means for recording information both sides of a film of material, the recording of the information being carried out by an etching process; and means for cutting the film to separate the microdots.
9. An apparatus for forming microdots comprising: means for transporting a film of material along a transport path; means for recording information both sides of a film of material, the recording of the information being carried out by a process which causes local burning of the film; and means for cutting the film to separate the microdots.
10. An apparatus according to claim 8 or 9, wherein the means for recording information comprises a laser on each side of the transport path.
11. An apparatus according to any one of claims 8 to 10 further including at least one camera, downstream of said means for recording information, for monitoring on the information recorded.
12. An apparatus according to any one of claims 8 to 11, further including means for causing the microdots to be received in a container.

S
13. An apparatus according to claim 12, having means for at least partially filling the container with adhesive.
14. A method of forming microdots substantially as any one herein described with reference to the accompanying drawing.
15. An apparatus for forming microdots substantially as herein described with reference to and as illustrated in the accompanying drawing.
16. A microdot formed by the method of any one of claims 1 to 7 or 14.