US4837061A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tamper-evident structures
Assignee: Rio Tinto Alcan International Ltd
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Filing: 1987-08-10
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Granted: 1989-06-06
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Expires: 2007-08-10
Abstract
Abstract The invention relates to a laminated tamper-evident structure which exhibits an irreversible colour change upon delamination. The structure includes a laminate of at least two layers (10,12) capable of generating a colour by a light interference and absorption phenomenon that requires direct and intimate contact between an adjacent two of the layers. The strength of attachment among the layers of the laminate is such that the laminate can be uniformly and reliably peeled apart at the interface between the adjacent two layers. An overlying flexible strip (14) of transparent or translucent material is adhered to the laminate to facilitate the peeling operation. Upon peeling apart the laminate, the generated colour is irreversibly lost, thus providing evidence that the structure has been tampered with. The structure can be incorporated into a variety of closable articles or products to provide evidence of opening or tampering.
Inventors
- 👤 Paul Smits
- 👤 Aron M. Rosenfeld
- 👤 Howard F. DeFerrari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:29
CPC Classifications
B; B65; B65D; B65D55/00; B65D55/02; B65D55/026; Y; Y10; Y10S; Y10S428/00; Y10S428/914; Y10S428/915; Y10T; Y10T428/00; Y10T428/14; Y10T428/1438; Y10T428/1443; Y10T428/24; Y10T428/24802
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
141 words
A tamper-evident structure which comprises: a laminate capable of generating a substantially non-dichroic colour by a light interference and absorption phenomenon, consisting of a layer of a metal of medium light reflectivity and a layer of a metal oxide, said layer of metal oxide having been formed by anodization in the presence of fluorine ions, at least in areas of the laminate where a colour change is desired; and an overlying flexible strip of transparent or translucent material suitable for facilitating the peeling apart of said laminate, said strip having a strength of attachment to said laminate that is greater than the strength of attachment of said layers in said desired areas; whereby peeling apart of said layers results in loss of said generated colour at least in said desired areas and re-attachment of said layers fails to re-generate said colour.
Claim 2
Dependent Claim
141 words
A tamper-evident structure which comprises: a laminate capable of generating a substantially non-dichroic colour by a light interference and absorption phenomenon, consisting of a layer of a metal of medium light reflectivity and a layer of a metal oxide, said layer of metal oxide having been formed by anodization in the presence of fluorine ions, at least in areas of the laminate where a colour change is desired; and an overlying flexible strip of transparent or translucent material suitable for facilitating the peeling apart of said laminate, said strip having a strength of attachment to said laminate that is greater than the strength of attachment of said layers in said desired areas; whereby peeling apart of said layers results in loss of said generated colour at least in said desired areas and re-attachment of said layers fails to re-generate said colour.
Claim 3
Dependent Claim
37 words
A structure according to claim 1 wherein said metal is selected from the group consisting of Ta, Nb, alloys of Ta and at least one anodizable metal and alloys of Nb and at least one anodizable metal.
Claim 4
Dependent Claim
27 words
A structure according to claim 2 wherein said at least one anodizable metal is a valve metal selected from the group consisting of Ti, Zr and Hf.
Claim 5
Dependent Claim
27 words
A structure according to claim 2 wherein said at least one anodizable metal is a refractory metal selected from the group consisting of W, V and Mo.
Claim 6
Dependent Claim
15 words
A structure according to claim 2 wherein said at least one anodizable metal is aluminum.
Claim 7
Dependent Claim
15 words
A structure according to claim 1 wherein said metal has a surface reflectivity of 40-60%.
Claim 8
Dependent Claim
28 words
A structure according to claim 1 wherein said layer of metal oxide is an oxide of the metal forming said layer of a metal of medium light reflectivity.
Claim 9
Dependent Claim
20 words
A structure according to claim 1 wherein said layer of metal oxide has a maximum thickness of about 1 μ.
Claim 10
Dependent Claim
14 words
A structure according to claim 1 wherein said laminate is supported on a substrate.
Claim 11
Dependent Claim
43 words
A structure according to claim 1 wherein a latent message or pattern is formed in said laminate by providing limited areas where said layers have a strength of attachment greater than the strength of attachment of the overlying flexible strip to the laminate.
Claim 12
Dependent Claim
30 words
A structure according to claim 1 wherein said layer of a metal of medium light reflectivity is a film that has been formed by sputtering the metal onto a substrate.
Claim 13
Dependent Claim
26 words
A structure according to claim 1 wherein said layer of metal oxide has been formed in its entirety by anodization in the presence of fluorine ions.
Claim 14
Dependent Claim
38 words
A structure according to claim 1 wherein said laminate contains a latent pattern formed by said desired areas and remaining areas of said metal oxide layer which adhere more strongly to said metal layer than said desired areas.
Claim 15
Dependent Claim
30 words
A structure according to claim 13 wherein said remaining areas of said metal oxide layer have been formed on said metal layer by anodization in the absence of fluorine ions.
Claim 16
Dependent Claim
20 words
A structure according to claim 13 wherein the latent pattern of desired areas and remaining areas forms a written message.
Claim 17
Dependent Claim
29 words
A structure according to claim 13 wherein the latent pattern enables said flexible strip to be peeled evenly and uniformly away from said laminate with a predetermined peel strength.
Claim 18
Dependent Claim
165 words
A kit of parts capable of forming a tamper-evident structure, said kit comprising: a laminate capable of generating a substantially non-dichroic colour by a light interference and absorption phenomenon, consisting of a layer of a metal of medium light reflectivity and a layer of a metal oxide, said layer of metal oxide having been formed by anodization in the presence of fluorine ions, at least in areas of said laminate where a colour change is desired; and a flexible strip of transparent or translucent material suitable for facilitating the peeling apart of said laminate, said strip being capable of being adhered to said laminate with a strength of attachment that is greater than the strength of attachment of said layers in said desired areas; whereby said flexible strip may be adhered to said laminate and caused to peel apart said laminate resulting in loss of said generated colour, at least in said desired areas, and whereupon re-attachment of said layers fails to re-generate said colour.
Claim 19
Dependent Claim
165 words
A kit of parts capable of forming a tamper-evident structure, said kit comprising: a laminate capable of generating a substantially non-dichroic colour by a light interference and absorption phenomenon, consisting of a layer of a metal of medium light reflectivity and a layer of a metal oxide, said layer of metal oxide having been formed by anodization in the presence of fluorine ions, at least in areas of said laminate where a colour change is desired; and a flexible strip of transparent or translucent material suitable for facilitating the peeling apart of said laminate, said strip being capable of being adhered to said laminate with a strength of attachment that is greater than the strength of attachment of said layers in said desired areas; whereby said flexible strip may be adhered to said laminate and caused to peel apart said laminate resulting in loss of said generated colour, at least in said desired areas, and whereupon re-attachment of said layers fails to re-generate said colour.
Claim 20
Dependent Claim
25 words
A kit according to claim 17 wherein said flexible strip supports a layer of adhesive to enable the strip to be adhered to said laminate.
Claim 21
Dependent Claim
35 words
A kit according to claim 18 wherein said layer of adhesive is covered with an easily peelable layer of backing material to protect the adhesive until the strip is to be adhered to said laminate.
Claim 22
Dependent Claim
194 words
A tamper-evident structure which comprises: a laminate capable of generating a substantially non-dichroic colour by a light interference and adsorption phenomenon, consisting of a layer of a metal of medium light reflectivity, a first layer of a metal oxide, a translucent layer of a metal of medium light reflectivity and a second layer of a metal oxide, said layers being arranged in the stated order and said second layer of metal oxide having been formed by anodization in the presence of fluorine ions, at least in areas of the laminate where a colour change is desired; and an overlying flexible strip of transparent or translucent material suitable for the peeling apart of said laminate, said strip having a strength of attachment to said laminate that is greater than the strength of attachment of said second layer of metal oxide to said translucent metal layer, at least in said desired areas, but less than the strength of attachment between other layers of said laminate; whereby peeling apart of said second metal oxide layer and said translucent metal layer results in loss of said generated colour and re-attachment of said layers fails to regenerate said colours.
Claim 23
Dependent Claim
194 words
A tamper-evident structure which comprises: a laminate capable of generating a substantially non-dichroic colour by a light interference and adsorption phenomenon, consisting of a layer of a metal of medium light reflectivity, a first layer of a metal oxide, a translucent layer of a metal of medium light reflectivity and a second layer of a metal oxide, said layers being arranged in the stated order and said second layer of metal oxide having been formed by anodization in the presence of fluorine ions, at least in areas of the laminate where a colour change is desired; and an overlying flexible strip of transparent or translucent material suitable for the peeling apart of said laminate, said strip having a strength of attachment to said laminate that is greater than the strength of attachment of said second layer of metal oxide to said translucent metal layer, at least in said desired areas, but less than the strength of attachment between other layers of said laminate; whereby peeling apart of said second metal oxide layer and said translucent metal layer results in loss of said generated colour and re-attachment of said layers fails to regenerate said colours.
Claim 24
Dependent Claim
41 words
A structure according to claim 20 wherein said metals of medium light reflectivity are selected from the group consisting of Ta, Nb, alloys of Ta and at least one anodizable metal and alloys of Nb and at least one anodizable metal.
Claim 25
Dependent Claim
20 words
A structure according to claim 20 wherein said translucent layer of metal is one that has been formed by sputtering.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-05 | 1992-12-05 | 1993-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-05 | 1996-12-05 | 1997-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-05 | 2000-12-05 | 2001-06-06 | $7700.00 | Window Closed / Lapsed |