WO2008120248A1

WO2008120248A1 - Device to transport support elements for electronic circuits, in particular photovoltaic cells, along a working line

Info

Publication number: WO2008120248A1
Application number: PCT/IT2007/000238
Authority: WO
Inventors: Andrea Baccini
Original assignee: Baccini SRL
Current assignee: Applied Materials Italia SRL
Priority date: 2007-03-30
Filing date: 2007-03-30
Publication date: 2008-10-09
Anticipated expiration: 2009-09-30
Also published as: TW200845270A

Abstract

Transport device (10) to transport support elements (11) in order to make photovoltaic cells or other electronic circuits, comprising a conveyor belt having a supporting surface on which the support elements (11) are positioned. The conveyor belt comprises at least a film (13) made of flexible plastic material and having a surface (15) covered, at least partly, with an adhesive material, and which defines the supporting surface. The adhesive material prevents the movement of the support elements (H) with respect to the film (13).

Description

"DEVICE TO TRANSPORT SUPPORT ELEMENTS FOR ELECTRONIC CIRCUITS, IN PARTICULAR PHOTOVOLTAIC CELLS, ALONG A WORKING

LINE"

* * * * * FIELD OF THE INVENTION

The present invention concerns a device to transport one or more support elements, for example silicon-based, known as wafers, in order to make photovoltaic cells, multi-layer printed circuits or more generally any electronic circuit, between different operating positions or work stations in a working or production line.

BACKGROUND OF THE INVENTION

It is known that photovoltaic cells, printed circuits or more generally electronic circuits substantially consist of a silicon support element, or wafer, on which a plurality of conductive tracks or other metalized or metalization elements are deposited.

Normally in methods to produce electronic circuits the silicon support element is moved by means of a transport device from a storage unit to at least a serigraphic printing station, where the conductive tracks are deposited. In other known solutions, the transport device moves the support element between other operating or working stations, for example for finishing the edges of the support, for completing the tracks, drying them or other operations.

A requirement present in such production methods is to guarantee a repeatable and extremely precise positioning, even in the range of thousandths of a millimeter, of the silicon support element with respect to the operating stations, in particular the serigraphic printing station.

To guarantee this, different techniques are known to move and position the support elements, which provide to use complex and costly transport devices.

In particular, it is known to use a conveyor belt made of fabric or rubber, provided with through holes or made with holed meshes, below which a suction unit is provided which creates a depression that keeps the support elements in contact with the belt, thus preventing it from moving with respect thereto.

Known transport means not only have the disadvantage of being costly and requiring the suction unit, but also they tend to get dirty easily, and so tend to transport the dirt onto the support element to be transported.

To prevent this, known belts have to be cleaned or replaced frequently.

Other known devices provide to use rather sophisticated and complex mechanisms, which use robotized units and sucker members to transport the support elements, or complex alignment and adjustment members that use preliminary optical detection apparatuses that identify the position, and members to correct the position of the support elements.

In any case, known solutions are extremely costly, both with regard to their production, considering the complexity of the components, and also with regard to their programming and operating management, since they require specific interventions to program and install dedicated electric and/or pneumatic plants.

Furthermore, known transport devices have the disadvantage that they require long maintenance times, with a consequent increase in management costs . Purpose of the present invention is to achieve a device to transport silicon-based support elements which not only guarantees that the positioning of the support elements is maintained with absolute precision, during their displacement from one operating station to the other, but is also simple and economical to make and which at the same time does not entail high management and maintenance costs.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages .

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claim, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purpose, a transport device according to the present invention is able to transport silicon-based support elements between several operating positions or work stations, and provides to use at least a conveyor belt made using at least a film of plastic material, having at least a supporting surface on which the support elements are able to be positioned. According to a characteristic feature of the present invention, on the supporting surface of the film there is an at least partly adhesive material, able to prevent the support elements from moving with respect to the film.

The film of plastic material, which by its nature is flexible, is disposed in association with said work stations, and is able to be moved in order to transport the support elements between one work station and the other.

The film of plastic material advantageously consists of a product already on the market, and currently used for other purposes, such as for example films for wrapping food or other products. The thickness of the film, and hence its resistance to traction and/or breakage, is chosen according to the specific applications and size of the conveyor belt to be made .

In this way, simple by providing to use a film of plastic material covered externally with an adhesive material, the correct and univocal positioning of the support element through the different operating positions is guaranteed, without needing to provide complex suction and/or robotized members or devices .

With the present invention it is therefore possible to reduce the costs of producing transport devices with respect to those of transport devices in the state of the art.

Moreover, the film of plastic material on which the at least partly adhesive material is present is easily and quickly replaceable, for example if its adhesive characteristics should fail, or if the supporting surface should get dirty, thus determining a reduction in the times and costs of maintenance interventions .

Another advantage of the present invention is the easy operating management of the transport device, which substantially does not require any specialized intervention or the installation of dedicated plants and/or specific programs for the functioning thereof .

In one form of embodiment of the present invention, the film of plastic material is supported from below by a support means, which defines a substantial planarity of its supporting surface.

According to another form of embodiment, the film of plastic material on which the at least partly adhesive material is present is disposed above, or to cover, a traditional conveyor belt disposed annularly between two drive pulleys.

BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a three-dimensional view of a segment of the transport device according to the present invention;

- fig. 2 is a schematic and lateral view of the transport device in fig. 1;

- fig. 3 is a schematic and lateral view of a first variant of the transport device in fig. 1;

- fig. 4 shows an enlarged section of the transport device in fig. 3;

- fig. 5 is a schematic view of a second variant of the transport device in fig. 1; - fig. 6 is a schematic view of a third variant of the transport device in fig. 1. DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT

With reference to the attached drawings, a transport device 10 according to the present invention is able to transport a plurality of support elements or wafers 11, silicon based, through an operating station, in this case a serigraphic printing station 12, in order to deposit on the surface of the wafers 11 a plurality of conductive tracks, in order to achieve for example a photovoltaic cell, a multi-layer printed circuit or other electronic circuits.

The transport device 10 according to the invention comprises a film 13 made of flexible plastic material and having a supporting surface 15 on which the wafers 11 are positioned in order to be transported through the serigraphic printing station 12.

In this case, the flexible plastic material that forms the film 13 is polyester, for example of the type known commercially as Domopack®. According to a first variant, the flexible plastic material is vinyl.

According to another variant, the flexible plastic material is mylar®. According to another variant, the flexible plastic material is kevlar®.

According to another variant, the flexible plastic material is PBO, for example zylon®.

In particular, on the supporting surface 15 of the film 13 there is an adhesive material having an adhesion force such as to prevent each wafer 11 from moving with respect to the film 13, once it is positioned on the supporting surface 15 of the latter and during its transportation through the serigraphic printing station 12. In the same way, the adhesive material present on the supporting surface 15 is such as to allow the wafer 11 to be easily removed downstream of . the serigraphic printing station 12.

An example of the adhesive material is that present on the transparent films normally used for the preservation of food in the house.

In the form of embodiment shown in figs. 1 and 2, the film 13 is wound between two reels 14, which not only cause it to advance along a determinate direction but also keep it under tension for a rectilinear segment 20, provided in correspondence with the serigraphic printing station 12.

In this embodiment, each new wafer 11 is positioned on a new portion of film 13, so as not to find any residual dirt, and hence guarantee an optimum positioning with absolute precision. In the variant form of embodiment shown in figs. 3 and 4, the film 13 is disposed next to the external surface of an annular belt 16, which is traditionally tensed and moved by means of two respective pulleys 17. In this case, under the rectilinear segment 20 of the annular belt 16, here too provided in correspondence with the serigraphic printing station 12, a supporting plane 19 is disposed that allows to define a substantial planarity of said rectilinear segment 20 of the annular belt 16 and consequently the film 13 disposed on said segment 20. In this way, the planar positioning of the wafers 11 on the film 13 is guaranteed, at least in correspondence with the serigraphic printing station 12. In this embodiment, after a predefined number of operating cycles, the film 13 is removed, and replaced by a new film 13 simply by winding the latter onto the annular belt 16.

In the variant form of embodiment shown in fig. 5, the film 13 is wound between two respective reels 21, disposed at the side of the annular belt, 16 and able to feed the film 13, in order to keep it disposed along the rectilinear segment 20 of the annular belt 16. Advantageously, the reels 21 feed the film 13 at a speed substantially corresponding, or in any case coordinated, with the speed of movement of the annular belt 16.

As shown in the variant form of embodiment in fig. 6, a single film 13 is provided, wound around the annular belt 16, and a gluer member 22 associated with a non-operative segment of the film 13, and able to deposit the adhesive material cyclically on the supporting surface of the film 13.

It is clear that modifications and/or additions of parts may be made to the transport device 10 as described heretofore, without departing from the field and scope of the present invention.

For example, it comes within the field of the present invention to provide that the film 13 is supported directly by the supporting plane 19 and moved by the pulleys 17, without the intercession of the annular belt 16.

It also comes within the field of the present invention to provide that the transport device 10 is associated with more than one operating station, for example an edging station, a completion station, a drying station and others. In this embodiment, the transport device 10 according to the present invention allows to feed the wafer 11 between one and the other of the operating stations, guaranteeing that the relative positioning of the wafer 11 is maintained.

It is also clear that, although the present invention has been described with reference to specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of device to transport support elements in order to make photovoltaic cells or other electronic circuits, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

1. Transport device to transport support elements (11) in order to make photovoltaic cells or other electronic circuits, comprising at least a conveyor belt having a supporting surface on which said support elements (11) are able to be positioned, characterized in that said conveyor belt comprises at least a film (13) made of flexible plastic material and having a surface (15) covered, at least partly, with an adhesive material, and which defines said supporting surface, said adhesive material preventing the movement of said support elements (11) with respect to said film ( 13) .

2. Device as in claim 1, characterized in that said flexible plastic material of said film (13) is polyester.

3. Device as in claim 1, characterized in that said flexible plastic material of said film (13) is vinyl.

4. Device as in claim 1, characterized in that said flexible plastic material of said film (13) is mylar®.

5. Device as in claim 1, characterized in that said flexible plastic material of said film (13) is kevlar®.

6. Device as in claim 1, characterized in that said flexible plastic material of said film (13) is PBO, e.g. zylon®.

7. Device as in any claim hereinbefore, characterized in that said film (13) is wound between two reels (14).

8. Device as in any claim hereinbefore, characterized in that said film (13) is disposed on a rectilinear segment (20) of an annular belt (16), which is moved by means of respective pulleys (17).

9. Device as in claim 8, characterized in that said film (13) is wound around said annular belt (16).

10. Device as in claim 9, characterized in that said film (13) is fed onto said annular belt (16) by means of two respective ^"reels (21).

11. Device as in any claim hereinbefore, characterized in that under said film (13) a supporting plane (19) is provided, which allows to define a substantially plane segment, so as to guarantee the positioning planarity of said support elements (11) on said surface (15) of said film (13).

12. Device as in any claim hereinbefore, characterized in that it also comprises a gluer member (22) associated with a non-operating segment of said film (13), and able to deposit said at least partly adhesive material cyclically on said surface (15) of said film (13).