Patent US6520669B1 successfully refreshed from Google Patents.
EP0215672A2
Expired / Lapsed
EP
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Sheet containing directional half-tone images and method for making the same
Assignee: 3M Co
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Filing: 1986-09-16
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Granted: —
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Expires: 2006-09-16
Abstract
Abstract A sheet containing an integrated directional, photographic image. Each sheet may contain one or more such images. Also a method for forming such images in microlens sheetings comprising directing a highly collimated light through an interposed half-tone mask.
Inventors
- 👤 Bruce D. Minnesota Mining And Orensteen
- 👤 Thomas I. Minnesota Mining And Bradshaw
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 15:36
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/126; G02B5/128
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
77 words
A sheet containing an integrated directional, photographic image characterized in that said sheet comprises: (a) a monolayer of closely spaced transparent microlenses, (b) a means for supporting said microlenses in said monolayer, and (c) a set of axial markings of substantially equal size, each marking located at the rear of a microlens at a position such that the set of axial markings is visible throughout a selected conical field of view as an integrated directional, photographic image.
Claim 2
Dependent Claim
77 words
A sheet containing an integrated directional, photographic image characterized in that said sheet comprises: (a) a monolayer of closely spaced transparent microlenses, (b) a means for supporting said microlenses in said monolayer, and (c) a set of axial markings of substantially equal size, each marking located at the rear of a microlens at a position such that the set of axial markings is visible throughout a selected conical field of view as an integrated directional, photographic image.
Claim 3
Dependent Claim
15 words
A sheet as defined in claim l further characterized in that said microlenses are microspheres.
Claim 4
Dependent Claim
15 words
A sheet as defined in claim 2 further characterized in that said microspheres are glass.
Claim 5
Dependent Claim
24 words
A sheet as defined in claim 2 or 3 further characterized in that said microspheres have an index of refraction between l.8 to 2.0.
Claim 6
Dependent Claim
47 words
A sheet as defined in any one of claims l-4 further characterized in that said sheet comprises a spacer layer of transparent material covering at least the back surfaces of said microlenses and wherein said axial markings are located on the back surface of said spacer layer.
Claim 7
Dependent Claim
43 words
A sheet as defined in any one of claims l-4 further characterized in that said sheet comprises a specularly reflective layer in contact with the back surfaces of said microlenses wherein each said axial marking is a structural alteration of an individual microlens.
Claim 8
Dependent Claim
40 words
A sheet as defined in any one of claims l-5 further characterized in that said sheet comprises a transparent material covering the front surfaces of said microlenses, and wherein said microlenses have an index of refraction of an least l.9.
Claim 9
Dependent Claim
41 words
A sheet as defined in any one of claims l-7 further characterized in that said sheet is substantially transparent and is adapted to be adhesively bonded over information areas of a document without appreciably interfering with the legibility of said information.
Claim 10
Dependent Claim
60 words
A sheet as defined in claim 8 further characterized in that said axial markings are disposed to provide an authenticating image which can be viewed only across a cone of about l0 to 20 degrees, and approximately at an angle to the face of said sheet which is appreciably different from the angles at which said document is normally viewed.
Claim 11
Dependent Claim
54 words
l0. A sheet as defined in any one of claims l-9 further characterized in that said sheet comprises a second set of axial markings disposed such that when said sheet is viewed within a second selected conical field of view, said second set of axial markings is visible as an integrated directional, photographic image.
Claim 12
Dependent Claim
53 words
A sheet as defined in claim l0 further characterized in that the conical field of view within which said second set of axial markings is visible as a photographic image does not overlap with the conical field of view within which said first set of axial markings is visible as a photographic image.
Claim 13
Independent Claim
70 words
A method of forming a sheet as defined in any one of claims l-ll characterized in that said method comprises: directing highly collimated light through a half-tone mask at a selected angle of incidence to the face of the sheeting to form an axial marking at the rear of each microlens which said light strikes such that the set of axial markings is visible as an integrated directional, photographic image.
Claim 14
Independent Claim
20 words
A method as defined in claim l2 further characterized in that said highly collimated light is a pulsed laser beam.
Claim 15
Independent Claim
20 words
A method as defined in claim l2 further characterized in that said half-tone mask is specularly reflective where not transparent.
Claim 16
Independent Claim
18 words
A method as defined in claim l2 further characterized in that said half-tone mask contains a negative image.
Claim 17
Independent Claim
21 words
A method as defined in claim l3 further characterized in that said laser beam scans the entire face of said sheeting.
References Cited (Backward Citations)
No citation records indexed.
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